Electric fan manufacturing involves the use of various machines and equipment to produce the components and assemble the final product.

For plastic electric fans manufacturing machine are mostly includes many plastic injection molding machines, part taking out robot, material auto-feeder, hopper dryer, water chiller, air compressor and other support equipment. Electric fans have many parts are made by plastic injection molding machines. Like electric motor cover, blades, blades protection guard, support pols, fan bas, electric control box are mostly produced by an injection molding machine.

Injection Molding Machine:
Injection molding machines are used to produce plastic components of electric fans, such as fan bodies, grilles, or control panels. The machines melt plastic pellets and inject the molten plastic into molds, which then cool and solidify to form the desired plastic parts.

Here are some other machines used in electric fan manufacturing:

Punching Machine:
A punching machine is used to create precise holes, slots, or shapes on metal sheets or components that form the structure of the fan. It uses hydraulic or mechanical force to punch through the material.

Stamping Machine:
A stamping machine is used to cut or shape metal sheets into specific fan components, such as fan blades or motor housings. It applies pressure to the metal sheets using dies and molds to form the desired shapes.

Motor Winding Machine:
Motor winding machines are used to wind copper or aluminum wires around the motor’s stator to create the electromagnetic coils. These coils are essential for generating the magnetic field that powers the motor.

Balancing Machine:
A balancing machine is used to ensure that the fan blades are evenly balanced to minimize vibrations and noise during operation. The machine measures the imbalance and provides corrective weights to achieve balance.

Welding Machine:
Welding machines are used to join metal components together, such as connecting fan guards or mounting brackets. Various welding techniques, such as spot welding or arc welding, can be employed depending on the specific requirements.

Assembly Line Equipment:
Electric fan assembly lines consist of various equipment, such as conveyors, workstations, and fixtures, to facilitate the efficient assembly of fan components. These machines aid in the sequential assembly of parts, attachment of wiring, installation of motors, and final quality checks.

Testing and Quality Control Equipment:
Electric fan manufacturing involves testing and quality control processes to ensure that the fans meet the required standards. This can include equipment such as noise measurement devices, airflow meters, temperature sensors, and electrical testing equipment to verify performance, safety, and functionality.

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Plastic materials have become an integral part of our daily lives, and we use a variety of plastic products every day. As an engineer in the plastics industry, understanding the plastics melting temperature, injection molding temperature, drying temperature and drying time of raw materials will help a lot in improving production efficiency, product quality and higher resource utilization.

What is the melting point or melting point temperature of plastic?

The melting point of plastic is the temperature at which a solid plastic material changes from a solid state to a molten state. At this temperature, the intermolecular forces holding the plastic polymer chains together weaken, allowing them to move more freely. That is, softening the plastic to a temperature where it flows better and is more conducive to injection molding. This melting temperature is not an exact temperature point, it is usually a larger or smaller temperature range, which is the heating temperature on the injection molding machine.

What is the plastic mold temperature?

The mold temperature in injection molding refers to the temperature of the cavity surface during injection molding. In-mold design and molding engineering condition setting must not only maintain the appropriate temperature, but also make it evenly distributed.

Uneven temperature distribution in the mold will cause uneven shrinkage and internal stress, making the molding opening prone to deformation and warping. The mold temperature in injection molding affects the molding cycle and molding quality. In actual operation, start from the lowest suitable mold temperature for injection molding of the material used, and then make appropriate adjustments according to the quality situation.

Plastic Melting Temperature and Injection Molding Temperature Chart

There are dozen types of plastic materials they are sure have different chemical structures and mechanical properties, and of cause the have deverse temperature ranges or melting points, and manufacturing processing temperature.

In below plastic rocessing chart, you will find most seen plastics` melt point temperature range, mold templerature range, material dry temperature, raw materail baking hour easy. And you can click the plastics short name to learn more details for the plastic charter and their injection molding processing conditions.
Table of Plastic Material Melting Point, Injection Molding Temperature, Baking Temperature and Drying Hours

Plastic Injection Molding Processing Conditions

ABS Injection Molding Processing Conditions

PP Injection Molding Processing Conditions

PU Injection Molding Processing Conditions

HDPE Injection Molding Processing Conditions

LDPE Injection Molding Processing Conditions

ACETAL Injection Molding Processing Conditions

PVC Injection Molding Processing Conditions

PET Injection Molding Processing Conditions

PMMA Injection Molding Processing Conditions

PS Injection Molding Processing Conditions

As we know, most of injection molding machine have 3 main parts: Machine`s Frame, Injection Unit & Clamping Unit. The machine`s controlling system connect these injection molding machine parts together to an injection machine. But fewer people knows how many components of injection molding machine have. As a prefessional injection molding machine manufacturer, today we would like to talk this topic and help more people to understand plastic injection machines better.

Frankly speaking, there are hundreds to more than a thousand components are assembled in an injection moulding machine. The number is not a solid word depends on the manufacturer, tonnage size and functions of plastic injection machine. There are dozens to hundreds parts difference for some different injection plastic machine.

Let`s make a sample with our Guanxin machinery`s different models. Our 160 ton small injection molding machine have about 500 kinds parts (more than 1300 pcs parts) on BOM list, but there are 700 kinds parts ( more than 1500 pcs parts) for our 1000 ton injection molding machine. And it`s with our standard configurations only, there are more if have some other part for different regions and countries used. We may need to add voltage stabilizer for Africa used, and voltage regulating transformer for some other countries not in 380V power. And that will cause many auxiliary coms is installed together.

Injection Molding Machine Parts and Functions

Below we will try to explain more about injection molding machine parts and their functions. We slide it into few main parts of injection machine for easies understand: The clamping unit, injection unit, electronic unit, hydraulic system, protecttion guard parts. These parts are named by there fuctions on an plastic injection molding machine. And it`s most known by people worldwide.

The clamping unit`s function is to hold the plastic mold and offer the clamping force for mold holding pressure when the molten plastic injected into the mold.

The injection unit`s function is used to melt the granule plastic and mixed with colorant and inject it to the plastic injection molding mold. The electronic unit is the control system of injection plastic machine, you can think it as the brain of the machine and offer the interface to human.

The hydraulic system turns the power from electric motor to mechanism movings, it`s the power supply chain on an plastic molding machine.

The protection guard is used to protect the machine from damage and keep human in safe for the machines movement and accidants.

Injection Molding Srcew and Barrel Parts and Functions

The parts of injection molding screw are screw body, screw rocket head, chuck ring and stop ring. The crew rocket head, chuck ring and stop ring are called as injection molding screw tip or 3 small parts by most of plastic molding machine manufacturers.

There are many parts for the barrel as well: injection molding barrel, barrel bracket, fasten bolts and nozzle head.

Injection Molding Machine Parts Name

We found some friends are searching the plastic injection molding machine parts or even for all the parts names. I think thats meaning less to list all the names as there are hundreds names. And it may be an eldless list due to there are lost of funcions are added onto the plastic molding machines. And there are many types of injection molding machines and the parts will be big different.

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What Is Liquid Silicone Injection Molding Process

Liquid Silicone Injection Molding Process is a manufacturing process which running liquid silicone rubber. It is different molding process comparing to the traditional plastic injection molding process. As their raw material is solid as granule, sheet, powdery. So liquid silicone rubber injection molding process will be absolutely different. LSR injection molding process will mainly need a silicone injection molding machine, liquid silicone metering and dosing machine, liquid silicone injection molding mold, and a traditional water-cooling chiller as well to keep the liquid silicone rubber cool and prevent it became cured before injected in the silicone molding mold.

Liquid Silicone Injection Molding Process

Liquid silicone rubber molding process is a rubber injection molding process but have other difference as well. Liquid silicone molding process need a liquid silicone metering and mixing equipment to control two-part component material combined in a ratio 1:1. And then supply to the silicone injection machine`s screw and barrel unit to remix and make the material is fully mixed even. Then the screw accurately injected it to a liquid silicone mold cavity. Then the silicone mold we be heated to a certain temperature to cured the liquid silica to a final solid product.

Please refer to below picture to help you understand the silicone rubber making process:

How to Understand Liquid Silicone Rubber Injection Molding Process

Below we will try to explain the liquid silicone rubber injection molding process step by step.

1st. The silicone material is supplied by 2 different component A & B is the same quantity with buckets (10KG) or drums (100KG). We put the drums on the platform like plunger and fixed it well. The plunger will inject the liquid silicone to the metering and dosing machine`s metering pump. And then the liquid silicone metering pump will pump these two-part silicone component to the mixing joint in 1:1 ratio. For some colored products it will need a colorant feeding unit to feed the color pigment to this joint as well. After all the liquid silica is join here then it will be feed to a static mixer to make it mixed even.

2nd. The first grade mixed silicone material will be supplied to the silicone injection mold machine injection screw and barrel. This liquid silicone material we be remixed again here. Just to ensure it`s fully combined even. The silicone injection moulding machine screw and barrel must keep cooled with the cooled water supplied by a water chiller. Here is one of difference between liquid silicone molding process and other plastic manufacturing processes.

3rd. The mixed liquid silicone is wait for injection when it goes to the head of the silicone machine crew. The injection nozzle is different also, as it is a auto shut-off pin valve nozzle. Just to avoid the liquid silicone getting leak when the nozzle do not keep touching the liquid silicone injection mold. Here have one of different injection molding process as well. The nozzle will left the silica injection mold after injection and pressure hold finish. Because the nozzle must keep cooled to prevent the liquid silica in it. But the silicone injection mold is heated to cured the liquid silicone in the molding mold.

4th. The cooled silicone is injected to the silicone mold. And then the liquid silicone molding mold will be heated and then the liquid silicone will be cured and convert to solid silicone products.

5th. The silicone injection molding mold will be open after the silicone product is injection molded finished. And then the silicone injection molding parts will be ejected by ejector or by auto air-blow ejected or token off with robot arm or human by hand. As liquid silicone injection molding parts is mostly elastic parts, liquid silicone rubber manufacturing process can produce lots of parts that could not produced by normal plastic manufacturing processes. Like products that have small mouth but bigger empty body.

What is the difference between LSR injection molding process and plastic injection molding?

After you learn above explanation of LSR injection molding process, you can easily find below difference between liquid silicone molding process and traditional plastic injection molding process.

Dedicated designed liquid silicone injection nozzle with auto shut-off function and water cooling system

1. The raw materials are in different format. Liquid silicone rubber injection manufacturing process is running liquid material. While normal plastic injection molding process runs solid plastics.

2. Liquid silicone injection moulding process is a process about chemical reaction process. LSR injection molding process needs two-parts compounds combined together and take chemical reaction under the chemical action of platinum catalyst. Silicone rubber molding process is a process that makes liquid silicone material to solid silicone products. Normal plastic injection molding process is solid material to solid products.

3. Liquid silicone injection molding requires components A and B are combined in a 1:1 ratio. Then normal plastic injection molding has no such requirement. Their raw material have a rang ratio for mixing.

4. Liquid silicone rubber manufacturing process need a dedicated silicone metering and dosing machine rather than a traditional material auto-feeder. The silicone metering and dosing equipment is precise and much more expensive than a plastic feeder.

5. Liquid silicone rubber molding process requires keeping raw material cooled before it`s injected to the mold. While plastic injection molding process is keeping raw material heated and melted.

6. Liquid silicone rubber injection molding process need special auto shut-off nozzle to prevent raw material getting leak.
7. Liquid silicone molding process is cold runner to hot runner process. While plastic injection molding process is hot runner to cold runner process.

Click below link to learning more about our optimized silicone injection molding machine and system:

Click Picture To Check Our LSR Molding Machine and Material Feeding System

Contact Us for LSR Silicone Injection Molding Machine Price

Food-grade liquid silicone rubber is a kind of addition-type two-component silica gel, divided into component A and component B. Component A is silica gel, and component B contains platinum catalyst. The entire addition-type two-component liquid silica gel is composed of platinum catalyst, 107 base gum, white carbon black and hydrogen-containing silicone oil. Among them, platinum catalyst is a very important component element. Only with the blessing of platinum catalyst can the two components AB be well solidified and formed.

What is sludge? Sludge is an indispensable auxiliary material in the application and production of silicone molds. Commonly used sludge materials mainly include the following types. One is 60% industrial clay (talcum powder), 30% flexible binder (grease or butter), and 10% solid binder (paraffin or petroleum jelly). The second type is wax 9% to 10%, sulfur 50% to 55%, ash 9% to 10%, grease (butter) 20% to 25%, and a little resin and pigment. The third type is construction sludge, which consists of clay and tung oil.

Sludge is mainly used for handicrafts, hardware, plastic mold making, and student sculptures. It can be recycled and will not deteriorate after being stored for a long time. It is characterized by being sensitive to temperature and can be softened and shaped at low temperatures. The sculptures of handicrafts and other models are extremely malleable.

So can the additive food-grade environmentally friendly silicone come into contact with the sludge? It depends on whether the components of the sludge contain heavy metals and other toxic impurities, that is, whether the sludge can pass food environmental certification. If the sludge contains heavy metals and toxic impurities, once the addition-type silicone comes into contact with the sludge, the contact surface between the food-grade liquid silicone rubber and the sludge will not solidify. The reason is that the platinum in the addition-type food-grade liquid silicone

The gold catalyst is a very active component with extremely strong chemical sensitivity. Once the platinum catalyst comes into contact with toxic substances in the sludge, it will cause the platinum catalyst in the silica gel to fail, thus directly affecting the solidification and molding of the addition food-grade liquid silica gel. .

Advantages of food-grade silicone materials

In many industries, the importance of material selection makes the difference in product quality and performance. Speaking of food-grade silicone material, it has occupied many fields and is widely used in many industries. But many people don’t know what are the advantages of food-grade silica gel compared with other silica gel products? Today Hongtu will analyze the advantages of food-grade silica gel for you.

One of the most important auxiliary materials for food-grade liquid silicone rubber raw materials is silica raw materials, which must first be guaranteed in terms of quality. Many silicone rubber product manufacturers require corresponding test reports before selecting and purchasing raw materials, and whether they will receive corresponding requirements. Silica is one of the most important materials in solid silicone, and its quality determines the performance of the material. Its heat resistance, temperature resistance, tensile strength, etc. are better than ordinary silica, so it is a high-performance material in high-temperature vulcanized silicone rubber and can meet the requirements of food grade, high transparency, and high stretchability.

Fumed silica gel is the heated food grade silica gel product of choice. It plays a major role in silica gel raw materials, because the silicon chain is fine and flexible, the product has high purity, improved hand feel, improved tensile life, and the normal service life is more than twice that of the ordinary precipitation method. Many food-grade silicone products in the market can meet FDA, ROHS and other test certifications and are environmentally friendly and non-toxic.

In the processing process of food-grade liquid silicone rubber product manufacturers, gas phase silicone has certain advantages in the processing and production process. It has strong plasticity and can be mixed more carefully during the rubber refining process. Adding toner and vulcanizing agent can make other The excipients melt more easily and keep the color bright to improve viscosity and fluidity.

Among the raw materials for silicone rubber products, fumed silica is an indispensable reinforcing material in silicone rubber. Due to its unique properties, it has gradually occupied many fields and is widely used in medical, daily necessities, cosmetics, skin care products and other industries.

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How to identify food grade silica gel

1. Distinguish from the smell of silicone products

Ordinary silicone smells pungent and has a strong smell. Food-grade silicone is non-toxic and odorless. It has no smell and is an environmentally friendly silicone.

2. Judging from the high temperature resistance of silicone products

Food-grade silicone’s high temperature resistance is generally 250 degrees, and its short-term high temperature resistance can reach about 350 degrees. However, ordinary silicone can only reach a maximum of about 150 degrees.

3. Judging from the stretch degree of silicone

Let’s take a silicone sheet of the same hardness as an example. Take a silicone sheet and stretch it with your hands, and pull it hard with both hands. If it turns white when you pull it and you can smell a pungent smell, it means it is ordinary silicone. On the contrary It is food-grade silicone that does not turn white when pulled and has good stretchability. Sometimes it won’t turn white when pulled. Because the manufacturer produces by-products during the vulcanization process, there will be a light smell. However, it is also food-grade silicone, which will not affect the product quality, and this smell can be eliminated by itself. of.

From the above food-grade silica gel identification methods, we can know that food-grade silica gel generally passes FDA food-grade certification, is non-toxic and tasteless, and has the characteristics of high temperature resistance, high tensile strength, and tear resistance.

Food-grade liquid silicone rubber has a wide range of application fields: it is generally used in the medical industry, electronics industry, baby products, aerospace and aviation industry, automobile industry and some daily necessities, etc. Some common products such as silicone baby pacifiers and silicone tableware are widely used

Food-grade silicone in silicone molds: can be used for automobile parts, military material parts, aerospace material molds, resin handicraft molds, car tire molds, yacht molds, chocolate molds, cake molds, etc.

food-grade liquid silicone rubber in terms of silicone products: can be used to make silicone prostheses, silicone chest patches, silicone masks, silicone dolls, silicone gaskets, adult products, simulated food, simulated dishes, medical-grade products, etc.

Food grade silicone maintenance tips

1. After each use of the silicone mold, you should clean it with hot water (diluted edible detergent) or put it in the dishwasher. Do not use abrasive detergents or foam to clean it. Make sure that the silicone gel is used and stored after each use. It’s all dry before.

2. When baking, the silicone molds should be placed flat on the baking sheet separately. Never dry bake the mold, such as a 6-piece mold. If you only need 3 molds, the other 3 molds must also be filled with water. Otherwise, the mold will be damaged and the service life of the mold will be reduced. In order to ensure that the finished product can achieve a good baking effect, you can lightly spray a small amount of anti-stick baking pan oil on the silicone surface of the mold before baking.

3. When baking is completed, please remove the entire baking tray from the oven and place the baked product on a cooling rack until it cools completely.

4. Silica gel can only be used in ovens, ovens, and microwave ovens. It is strictly prohibited to use gas, open flames, or electricity, or use it directly above the heating plate or below the barbecue.

5. Please do not use knives or other sharp objects on silicone products, and avoid heavy pressure and pulling.

6. Due to static electricity, silicone molds are prone to dust. If not used for a long time, they should be placed in a carton away from direct sunlight.

7. Please do not rinse the silicone mold with cold water immediately after it comes out of the oven to extend its service life.

Things to use when using food silicone raw materials:

1. When using, food-grade silicone raw materials must be fully exposed to the air. The larger the contact area, the faster the curing. On the contrary, the curing will be slower or even non-curing. The thicker the adhesive layer, the longer the vulcanization time. The greater the humidity and the higher the temperature in the same environment, the faster the curing speed of the adhesive layer. The opposite is true.

2. This food-grade silicone raw material product is a non-dangerous chemical and can be stored and transported as non-dangerous goods. When used, it does not cause poison or pollution to the human body and the environment, so there is no need to take too many preventive measures.

3. Products should be kept dry and protected from sunlight and rain during storage and transportation. The effective storage period is 12 months. If it exceeds the storage period, it can still be used after passing the inspection. After using the product, the hose should be tightly capped immediately and can be kept for reuse.

4. First clean the components to be glued to remove oil stains on the surface, then squeeze out the product from the silicone raw material hose and apply it on the surface of the components. When the glue comes into contact with the moisture in the air, it begins to flow from the surface. and gradually solidifies into an elastomer.

What is the mark of food grade silicone?

Generally, food-grade liquid silicone has relevant certificates such as RoSH, SGS, Reach, and MSDS to confirm its safety.

How to identify the quality of food grade silica gel

First of all, look at the appearance. The food-grade silicone liquid made of new and good materials is transparent and bright, and the colloid is also very delicate. The phenomenon shown is that the liquid silicone gel has very good fluidity and is very smooth. The color of liquid silica gel produced from waste rubber cracked materials is yellow and opaque, and the silicone oil layer in the glue is not evenly separated. Poor liquid silicone has obvious lumps and impurities when stirred, and its fluidity is poor.

The second is the smell. Really good food-grade silicone has no smell, is environmentally friendly, non-toxic and tasteless. The liquid silicone produced from cracked materials uses inferior silicone oil and base rubber. This poor material has a certain smell and cannot be completely environmentally friendly, non-toxic and tasteless.

The last step is to look at the effect after curing. After the liquid silicone made from imported raw materials is cured, the surface is very dry and there is no oil or stickiness. After the silicone made from ordinary cracked silicone is cured, especially zero-degree liquid silicone is particularly prone to leakage. Oily and sticky.

Analysis of the reasons why food-grade silicone materials do not solidify

One characteristic of addition-type food-grade silica gel is that when it comes into contact with non-environmentally friendly materials such as sulfur, tin, lead amine, etc., it will be poisoned and will not solidify. The liquid silica gel will form into lumps or solidify. The back surface becomes sticky or cannot be cured at all, resulting in production waste. Therefore, contact with sulfur-containing lead-tinamine substances must be avoided during production, including mixing equipment, containers, etc.

The second reason for non-curing: The AB component must be fully stirred evenly. If not stirred evenly, the glue will not solidify, or the curing will be incomplete, similar to sticky hands.

The third reason: AB component is not added according to the proportion. If component A or component B is added more or less, it will also cause incomplete curing of silicone. Regarding the incomplete curing of addition-type food-grade liquid silicone, The common ones are mainly the above points, and there are many more that you still need to explore slowly by yourself during production.

What are the testing standards for food-grade silica gel?

In terms of performance testing of food-grade silicone addition liquid silicone, it is mainly judged based on the following parameters, including hardness, viscosity, tear strength, tensile strength and elongation. The hardness of food-grade liquid silicone ranges from Shore A0 to 60 degrees, with units every 5 degrees in between. The viscosity of addition-type food-grade silicone is generally below 10,000 cps. As the hardness of the silicone becomes higher, its viscosity will also increase.

Other properties such as tear resistance also change with the change of hardness parameters. The general rule is that the higher the hardness, the worse the performance of silica gel will be; anyway, the lower the hardness, the worse the performance of silica gel will be. The hardness is in the range of 20-30 degrees, and the performance strength of addition-type silicone is the most suitable.

In terms of environmental performance testing of additive food-grade liquid silicone rubber, there are many standards and different methods. First of all, you need to check whether the additive food-grade silicone has a pungent smell. If there is a pungent smell, it is industrial-grade liquid silicone. Secondly, look at the ratio of silica gel. The ratio of addition-type silica gel is mostly 1:1 or 10:1, while the ratio of industrial-grade silica gel is mostly 100:2. The last step is to check whether the addition-type silica gel is prone to poisoning reactions. The main reason is that food-grade silica gel comes into contact with toxic and harmful elements such as heavy metals, which will cause the addition-type liquid silica gel to be poisoned and not solidify.

How to reduce bubbles in food-grade liquid silicone without a vacuum machine?

When food-grade liquid silicone is mixed and stirred, air is mixed into the liquid silicone during the mixing process due to the contact between the liquid silicone and the air, thereby forming bubbles. Too many bubbles will make the molded silicone mold look ugly, and the molded product will also have many pores. Under normal circumstances, we will use a vacuum machine to remove air bubbles, but in the absence of a vacuum machine, how to remove air bubbles from food-grade liquid silicone without a vacuum machine?

If there are only a few bubbles on the surface, it is because the bubbles brought in when the silica gel and curing agent are mixed are not completely eliminated, so when we stir, we need to stir clockwise along the wall of the container. When pouring, we can The liquid silicone flows slowly downward in a filamentous shape, so that the bubbles can be eliminated while pouring the glue. After filling, the bubbles on the surface can be popped with a toothpick.

Food-grade silicone can withstand high temperatures. When encountering a large number of bubbles, we can use a slightly higher temperature to bake the curing agent of the liquid silicone to eliminate impurities, reduce the bubbles, and then use a hair dryer or air gun to blow away the bubbles; of course Also pay attention to whether the mold is for food, such as chocolate molds. You can use an air gun to blow away surface bubbles.

We can also extend the curing time by controlling the ratio of silica gel to curing agent and buy time for the bubbles to naturally discharge. For example, the weight ratio of food-grade silica gel to catalyst is 1:1. We can slightly reduce the catalyst and the two components. The cross-linking reaction is quick-frozen, so that the bubbles in the liquid food-grade silica gel will be slowly discharged upward to reduce the bubbles; you can also negotiate with the food-grade liquid silica gel manufacturer during the ordering process to adjust the operating time to control the elimination of bubbles.

The above-mentioned methods of using toothpicks or sharp air to pop bubbles, or using a hair dryer or air gun to disperse bubbles can only eliminate a little of the bubbles on the surface of food-grade silicone, but it does not ensure that the entire silicone product is bubble-free. If you want to remove the bubbles cleanly, you must use vacuum to remove the bubbles.

Can liquid silicone be disinfected with water? How long is appropriate for disinfection?

Silicone itself is very stable. If it has passed the food grade, it will not change easily. However, you should pay attention to the use environment and try not to use high temperatures above 250 degrees for baking. Food-grade silicone materials have a variety of unique properties. In addition to In addition to high temperature resistance, it can also fully adapt to low temperature environments and climate. In terms of stability, the main components of silicone material are silica, silicone resin and white carbon black. In addition to the catalyst added by the silicone product manufacturer (sulfide agent) will not conflict with any substance, and the catalyst smell can be removed through secondary fluidization and high-temperature baking.

Liquid silicone is an extremely easy-to-clean material and does not require the use of chemicals such as detergent. Furthermore, silicone has good waterproof properties. In addition to pure silicone products, many are made of multi-material metal-plastic composite materials, so it is recommended that the boiling and disinfection time be between 5-15 minutes is more suitable. In addition to boiling in boiling water, the silicone products produced by regular mold silicone manufacturers can also be used in the microwave oven, which is very convenient. However, you must also be careful not to buy fake and shoddy products, otherwise it will be very dangerous. May cause harm to the body.

Generally speaking, regular liquid silicone rubber products can be boiled in boiling water, which can disinfect and sterilize without producing any toxic substances. Food-grade silicone is often formed using liquid silicone after solidification, and its high temperature resistance range is – Between 60℃-230℃, therefore, it can be suitable for direct disinfection by boiling in water.

Application trends of food-grade liquid silicone rubber

According to the report published by Virtue Market Research in 2022, the Global Food Grade Silicone Rubber Market was valued at $976.9 million, and is projected to reach a market size of $1389.25 million by 2030. Over the forecast period of 2023-2030, market is projected to grow at a CAGR of 5.5% .

The global food grade silicone rubber market size was USD 670.78 Million in 2022 and is expected to register a revenue CAGR of 6% over the forecast period, reaching $1.13 billion by 2032.

Food-grade liquid silicone products use the LSR injection molding process (also called liquid silicone injection molding). The two-component or multi-component liquid silicone mixed fluid is pressurized and injected into the heated mold through an injection molding feeder. After curing and molding, it is Production can be completed. Compared with other production processes, the liquid silicone injection molding process has good automation and no waste of raw materials. The injection molded rubber can be fully automated and does not require too much human participation. It can also control manufacturing costs and raw materials.

Food-grade liquid silicone rubber products are also very economical and practical in daily life. Liquid silicone has good tear and wear resistance, and can also be anti-fall and shock-proof. It can be a good substitute for our commonly used fragile items. In addition, liquid silicone products are also soft and skin-friendly, and can well come into contact with human skin without causing adverse reactions. Liquid silicone products also have excellent chemical inertness and can be exposed to a variety of foods and substances without causing changes and material reaction.

According to statistics, the procurement and application volume of liquid silicone in 2018 reached more than 1.6 million tons. The penetration rate of liquid silicone application in various industries will reach more than 40% in 2021. Food-grade liquid silicone will usher in explosive growth in various industries. The food-grade liquid silicone molding process mainly covers consumer electronics such as mobile phones, smart wearables, handheld terminals, connectors, automobiles, medical fields, etc., especially the field of smart terminals will be a new generation of 3-proof process innovation.

Food-grade silicone products are widely used in mechanical products such as coffee pots, water heaters, bread machines, disinfection cabinets, water dispensers, kettles, irons, rice cookers, fryers, pulp machines, and burning appliances. Machinery, electrical appliances, electrical and other industries. Such as: protective covers for water dispensers, coffee pots, beauty salon equipment and lighting products; as well as food replicas, chocolate molds, candy molds, infant comfort toys, food cake molds, various food mats, baby bibs, silicone ice Grids, silicone pacifiers, etc.

Features of food-grade liquid silicone rubberproducts:

High temperature resistance: applicable temperature range -40 to 230 degrees Celsius, can be used in microwave ovens and ovens.

Easy to clean: Silicone products produced from liquid silicone can be cleaned by rinsing with water after use, and can also be cleaned in the dishwasher.

Long life: The chemical properties of silicone materials are very stable, and the products produced have a longer life than other materials.

Soft and comfortable: Thanks to the softness of silicone material, cake mold products are comfortable to touch, relatively flexible, and do not deform.

Various colors: Different beautiful colors can be blended according to customer needs.

Environmentally friendly and non-toxic: No toxic or harmful substances are produced from raw materials entering the factory to finished product shipments.

Insulating properties: Silicone rubber has a high resistivity and its resistance remains stable over a wide temperature range and frequency range. At the same time, silica gel has good resistance to high-voltage corona discharge and arc discharge, such as high-voltage insulators, TV high-voltage caps, electrical components, etc.

Low temperature resistance: The critical point of ordinary rubber’s operating temperature is -20 degrees to -30 degrees. However, silicone rubber still has good elasticity at -60 degrees to -70 degrees. Some specially formulated silicone rubbers can also withstand higher temperatures. Low temperature, such as low temperature sealing rings, etc.

Conductivity: When conductive fillers (such as carbon black) are added, silicone rubber has good conductive properties, such as keyboard conductive contact points, electric heating element components, antistatic components, high-voltage cable shielding, medical therapy conductive film, etc.

Weather resistance: Ordinary rubber degrades rapidly under the action of ozone generated by corona discharge, while silicone rubber is not affected by ozone, and its physical properties only change slightly when exposed to ultraviolet rays and other climate conditions for a long time, such as those used outdoors. Sealing materials, etc.

Thermal conductivity: When certain thermal conductive fillers are added, silicone rubber has good thermal conductivity, such as heat sinks, thermal seals, copy machines, fax machine thermal rollers, etc.

What are the common problems in using food-grade silicone products?

1. Food-grade liquid silicone rubber tableware

Silicone tableware is easy to use, non-toxic and odorless, and does not release harmful substances. More importantly, it can withstand high-temperature boiling without deformation or wear. However, there are also problems that need to be paid attention to when using silicone tableware:

Foods containing high amounts of acid or grease cannot be served with silicone tableware, because silica gel will react chemically with acid and grease, causing the silica gel to decompose and affecting food safety. Therefore, silicone tableware is best used only to hold harmless foods such as rice and noodles.

When using silicone tableware, be careful to avoid small particles of food, such as rice grains, minced meat, animal bones, etc., because these things will scratch small cracks on the surface of the silicone and affect the performance and safety of the silicone.

Food-grade liquid silicone rubber tableware cannot be heated in the oven or microwave, otherwise it will deform and melt due to excessive temperature.

Food-grade liquid silicone rubber tableware should be cleaned regularly, preferably with warm water and neutral detergent. Scratching tools such as brushes should not be used to prevent the silicone surface from being scratched and affecting safety.

2. Food-grade liquid silicone rubber baking pan

Silicone bakeware is a common product among silicone products. It is not only suitable for baking cakes, bread and other baked goods, but is also widely used in microwave ovens, steam ovens, etc.

Before baking, a layer of cooking oil must be applied to the surface of the silicone baking pan to ensure smooth demoulding of cakes, bread and other foods. But be careful not to apply too much oil, otherwise it will affect the quality and taste of the food.

The griddle can be heated in the oven, but the maximum temperature must not exceed 450℉ and it cannot be used over an open flame or on the grill. In addition, the baking pan should not be exposed to the sun to avoid losing its high temperature resistance, weather resistance and other properties due to excessive exposure.

When heating the silicone baking pan in the microwave, you must check the baking pan for damage and cracks and replace it as soon as possible if necessary. In addition, the time in the microwave oven should not be too long, try to control it within 3 minutes.

3. Food-grade liquid silicone rubber injection mold

Food-grade liquid silicone injection molds are mainly used to make candies, chocolates, cakes and other foods. Because silica gel has good flexibility and is non-toxic and tasteless, it is very popular in the food manufacturing industry. However, there are some issues that need attention during use:

Before using the silicone mold, be sure to clean it with clean water, and then apply a thin layer of oil on the surface to prevent the food from sticking inside. But be careful not to apply too much, so as not to affect the taste of the food.

During use, be careful not to scratch the surface of the mold. If there are scratches on the surface, it will easily absorb stains and make it difficult to clean. Therefore, when using silicone molds, you should use kitchen utensils such as stainless steel shovels that will not scratch the surface of the mold.

Silicone molds cannot be exposed to open flames and high-temperature environments, and they must not be exposed to sunlight to avoid losing elasticity, cracking, and becoming sticky due to high-temperature burning and excessive exposure.

4. food-grade liquid silicone rubber coasters

Food-grade liquid silicone coasters are a kind of tableware used to place cups, water cups, glasses, etc., which not only protect the tabletop, but also prevent the cups from sliding and making them less likely to fall over. However, there are also issues that need to be paid attention to when using silicone coasters:

Food-grade liquid silicone rubber coasters can be cleaned with mild detergent and warm water, and can be temporarily placed on the cleaning table to dry after use. But be careful not to wash it in the dishwasher or use bleach, so as not to affect the quality and life of the silicone.

When using food-grade liquid silicone coasters, avoid dropping the cup heavily on the mat, as this will shorten the service life of the silicone. It is also not advisable to let leaking water from the cup spill onto the silicone coaster to avoid gelatinization and damage to the silicone.

Food-grade liquid silicone rubber coasters should be stored in a cool place in the kitchen to avoid prolonged exposure to sunlight. At the same time, be careful not to stack them during storage to avoid leaving obvious marks and affecting the quality.

The performance requirements of human body-specific silicone raw materials are higher than those of general mold silicone raw materials or pad printing glues. It needs to be specially prepared, so the output is relatively small; the most important thing is that there is less demand from customers.

What is the performance of human-like silicone materials? How long is the service life?

Human body silicone rubber manufacturer’s imitation human body silicone is a kind of addition type silicone rubbes. It is a low viscosity 1:1 series A and B two-component silicone. The overall hardness is relatively low, about 0 to 15 degrees. If the hardness is too high, it will broken away from the category of human-like silicone. It is used to make artificial human masks, headgear, artificial human models, and adult products. The mixing viscosity is around 1000-3000cps. The operation method is manual, which is similar to the operation method of silicone for ordinary molds.

As for its service life, it can be divided into storage life in liquid form and service life of the finished product after curing.

Human body-like silicone is specially produced through a special process. It has special properties of high temperature resistance, aging resistance, acid and alkali resistance. The uncured two-component body-simulating silicone A and B will never solidify without mixing, and will always remain in a liquid state. Just as time goes by, the water inside the liquid silicone gradually evaporates, and the remaining silicone components will precipitate, and the overall viscosity of the silicone will become thicker. At this time, you only need to add some silicone oil and stir quickly, and it will become very thin. Can be operated multiple times for long-term storage. Generally, additive liquid silicone and human-like silicone need to be kept in a cool place away from direct sunlight. Generally, the longest shelf life is about 12 months.

The liquid form human-like silicone materials service life is about one year. Then how long is the shelf life of cured silicone products?

In fact, cured silicone products can be left without any change for 5-10 years under normal use and proper maintenance. Although it can withstand high temperatures, the biggest fear is using it at high temperatures. If the cured human-like silicone is baked at high temperature for a long time, the color will turn yellow, the hardness will become hard, and the performance will deteriorate. The molecular structure inside the silicone will be destroyed, the performance will decrease, and the use value may be very short.

Precautions:
Liquid human body silicone should be stored in a sealed manner, and the mixed human body silicone should be used up at one time within the specified time to avoid waste caused by solidification of the rubber;

* Avoid contact between rubber and materials containing nitrogen (N), phosphorus (P), sulfur (S), tin (Sn), lead (Pb), mercury (Hg), alcohols, water, etc., such as organotin compounds and organic compounds containing Tin silicone rubber sulfur, sulfide, sulfur-containing rubber, ammonia compounds and ammonia-containing materials cannot come into contact with containers or molds that have been adjusted for condensation rubber. Otherwise, the surface of the addition liquid silicone rubber will become sticky, Incomplete curing or even no curing.

* When operating, it must be distinguished from containers that have been used in condensation silica gel. Use unused room temperature silica gel tools to operate this silica gel to avoid non-curing or sticky surface, signs of incomplete curing or even non-curing. At the same time, avoid Such as contact with sludge, various types of clay, putty, and solder.

What are the applications of human body-like silicone raw materials?

1. Physical dolls, needless to say, they are called human silicone because they are made of physical dolls.

2. Suture practice modules are used for medical practice. The effect is definitely the closer to human skin, the better. They must be environmentally friendly, so human body silicone can be used to make suture practice modules.

3. The aircraft cup has basically the same requirements as the physical doll, so it can be made of human body silicone.

4. Silicone breast prostheses are definitely needed for environmental protection, softness, and close to human touch. Human silicone is the most suitable.

5. The robot skin must have strong tear resistance and a certain degree of self-healing properties. Human body silicone is very suitable.

6. Silicone film and television masks have very good simulation effects and are environmentally friendly. They can be made from human body silicone.

7. Human prosthetics are just like physical dolls…

8. Artificial dildo. In fact, the hardness needs to be adjusted when using human silicone to make an artificial dildo. Everyone knows the reason, but the hardness of human silicone can be adjusted. So it fits.

9. Toy balls for venting are environmentally friendly and safer because they are often in contact with hands. They can be made of human body silicone.

10. Other products with similar requirements can be made of human body silicone.

Human body silicone has a wide range of applications, and the physical dolls produced are becoming more and more recognized by the public. The emergence of intelligent robots will create greater demand for human body silicone.

As one of the leaders of professional injection molding machine manufacturers in China, Guanxin has a lot of production design experience in the special plastic injection moulding industry. The most important optimization design in special plastic injection molding equipment is the special customized design and production of injection molding screws and barrels and their related kits. Below we mainly introduce the knowledge about injection molding screw and barrel.

Universal injection molding screws and barrels
We all know that the plastics industry has a variety of plastic raw materials with different performance characteristics. Some of them have the same performance characteristics, some have little difference, and some have very big differences. There are thermoplastic and thermoset plastics, and there are strict and loose temperature controls, etc. Therefore, the injection molding screws has a universal plastic screw and barrel and many special injection molding screw types(link LSR silicone injection molding screw type, PET preform injection molding screw, PVC/PPR pipe fittings injection molding screw type, etc ). When selecting the plastic injection molding machine, we must choose the appropriate injection screw and barrel according to the plastic material to be processed, so that we can produce excellent plastic products with high precision and consistency.

Parts and Components of Injection Molding Screws and Barrel

There only a fewe parts and pomponents of injection molding screws and barrel only, but the injection molding screw is very imporntant to an plastic injection machine. The injection molding screw is comprised of four main components: injection moulding screw body, screw rocket head, chuck ring and stop ring. And the screw barrel includes injection molding barrel, barrel bracket, fasten bolts and nozzle head.

Designs and Functions of Injection Molding Screws

1. The overall surface of the three small parts of the screw head must be smooth. Except for the assembly part, there must be no right-angled or acute corners in any place that can be seen from the front. They should be smoothly transitioned. The size of the smooth R depends on the situation, because right-angled and acute corners The dead corners are prone to cracking, not to mention the accumulation of materials, which makes the flow of raw materials not smooth enough. After being used for a long time, it is easy to have black spots and yellowing. The three small parts are the parts most likely to produce yellowing. Many PC, PMMA and other products are used for yellowing. Three small pieces were abnormal and turned yellow.

2. The design of the two end faces of the apron is also particularly important. Nowadays, many injection molding machine manufacturers design the joint surface of the apron and the meson to be flat and have no slope. This has two disadvantages. First, there is plane contact and no slope contact. If the surface is large, the service life will be much shorter than that of the inclined surface. Secondly, the joint between the meson and the screw head without the inclined surface will become a dead angle. If the raw material stays for a long time, there will be black spots and yellowing. This slope is the most 30 degrees is better, 15 degrees is not big enough and it is easy for material to accumulate. 45 degrees has a large contact surface and is not easy to accumulate materials, but it is easy to push through the rubber ring when injecting glue.

3. The left and right movable clearance of the apron should be moderate. Depending on the raw materials produced, the movable clearance should be large or small. The instability of the glue injection point of many large-scale thin-walled products is due to the large left and right movable clearance of the apron. .There are also many PMMA and PC raw materials that make a rattling sound during production because the left and right movement gaps of the rubber rings are too small, resulting in unsmooth discharging.

4. The surface of the threaded part of the screw head does not need to be as hard as other parts. Too high hardness can easily cause the thread to pop off and reduce the thread strength. It should be protected by nitrogen barrier before heat treatment. Or the thread should be processed after nitriding. The threaded part should be withdrawn. It is best for the groove to be an R shape of an arc, rather than being cut directly with a right-angled turning tool. That way the stress is better, as many screw heads break at this location.

Some important knowledge about injection molding screws

The injection screw seems to be a very simple injection machine accessory, but it has to complete many different functions at the same time.

1. Conveying or feeding solid or liquid plastics;
2. Compressing, melting and pressurizing melts;
3. Mixing, melt refinement, and pressure and temperature stabilization.

The injection screw is divided into three different parts or areas, each of which performs different functions, It includes three main injection molding screw zones as shown in the figure below.

1. Feeding part of plastic raw materials
2. The melted, plasticized and pressurized part of the plastic
3. Plastic injection metering part

Feeding section of plastic raw materials

The beginning of the feeding section of plastic raw materials is used to load unmelted plastic introduced into plastic pellets or plastic hoppers. When the injection screw rotates, the plastic continuously enters the groove before the screw thread and advances toward the nozzle by following the screw thread.

As the resin advances further along the feed section, densification (compaction) occurs as the particles or granules are pressed more closely together. The motion of a solid is always enhanced by either increasing the friction between the plastic and the inner surface of the barrel or reducing the friction between the plastic and the screw surface. In other words, if it sticks to the barrel and slides on the screw, the feeding effect is good.

Impact of plastic raw materials

The form of material entering the feed hopper or feeding section has a very important impact on whether the processing can be fed. For example, powdered and fluffy regrinds generally cause difficulties in the conveying and processing of plastic raw materials than pellets, cubes and heavier regrinds. That’s why we ask our customers questions about raw material production: Are virgin plastic pellets or recycled plastic in powder or flake form used in daily production? Or is it a mix of new materials and recycled plastics? What is the proportion of new and old materials? Because we have to choose injection screws of different designs according to the materials used.

The melt plasticizing and pressurizing section of the injection screw

The melt plasticizing or compression section of the injection screw is a section of the screw where the depth of the screw’s threads loading the plastic gradually transitions from the deep feed section to the shallower plastic metering section. Because of the many different functions that are performed during this length, the design of the transition is critical to the performance of the screw.

The main functions to be completed by the melting, plasticizing and pressurizing part of the injection screw include the following three important performances:
(1) Melting,
(2) Compaction and elimination of voids
(3) Pressure accumulation.

Melting: Although melting occurs in the feed and metering sections, most of it occurs in the transition section. As the pitch and channel depth of the injection screw threads decrease, the solid plastic will slowly be compressed and rub against the heated injection barrel. This provides efficient frictional heating and melting of the plastic raw material as well as some additional but less efficient conductive heating. By compacting and eliminating voids in the transition section, the polymer changes from compacted particles with air gaps in between to molten polymer without air bubbles.

Plastic injection screw metering section

The metering part has a very important impact on the injection accuracy of plastics. The word “metering” comes from the concept of a constant thread groove depth part, which measures a smooth and precise amount of plastic to ensure precise control of the plastic injection volume. This has a key impact on the precision and intelligent production of plastic products today. .

The metering part of the plastic injection screw should complete the first or more of the following functions:

1. Metered uniform plastic delivery volume, pressure and melt temperature.
2. Melting of some stubborn particles
3. Melt refinement
4. Molten plastic is inside the injection barrel and maintains constant melting pressure

Injection molding screw`s shear rate or L/D length to diameter ratio

Most of the energy in the compressed portion of a plastic material is obtained through shear. The plastic is sheared between two relatively moving surfaces. These shearing activities are usually performed in the inner wall of the injection barrel and the threaded grooves of the screw.

The actual shear rate at any single point along the screw can be calculated using the following formula.

“S=DN/19.1*h”

where S = shear rate (reciprocal seconds)
D = screw diameter (inches)
N = screw speed (rpm)
h = Thread groove depth (inches)

The relationship between screw desing and plasticizing quality

The main factors affecting plasticizing quality: L/D slenderness ratio, compression ratio, back pressure, screw speed, and electric heating temperature setting.

L/D ratio = screw working length/screw diameter. If the L/D ratio is large, it is easy to eat the ingredients evenly, but it is easy to overdo it. For plastics with better thermal stability, a longer screw can be used to improve mixing properties without worrying about scorching and yellowing; for plastics with poor thermal stability, a shorter screw can be used or the screw end has no screw tips auxiliary.

L/D slenderness ratio designs for different plastics:

Thermoset: 14～16
Rigid PVC, high viscosity PU, etc. Thermal sensitivity: 17～18
General plastic: 18～22
High temperature stability plastics such as PC, PPS, PC+ABS: 22～24

L/D slenderness ratio effections for color mixing ability:

12~16 It is advisable to shape the rubber particles with good color to avoid color difference.

16~18 The color masterbatch is mixed, dyed and molded in the material tube with uniform quality and small color difference.

20-24 The colorants are mixed and dyed in the material tube, and the dispersion is uniform, which has a better protective effect on the physical properties of the finished product.

Compression ratio: Compression ratio = feeding tooth depth/metering tooth depth. Consider the compressibility of the material, the degree of feeding, backflow, the density of the product, heat transfer and exhaust.

Appropriate compression ratio can increase the density of plastic, make the molecules more tightly bonded, help reduce the inhalation of air, reduce the temperature rise caused by pressure, and affect the difference in output. Improper compression Than will destroy the physical properties of plastic.

The higher the compression ratio, the higher the temperature rise generated during the plasticization process of the plastic in the material tube, resulting in better mixing uniformity for the gelling plastic, and the relative discharge volume is greatly reduced. High compression ratio is not suitable for fusible plastics, plastics with low melting viscosity and poor thermal stability.

The small screw has a shallow groove depth and absorbs heat quickly, which is enough to soften the plastic during the compression section. The friction heat energy between the screw and the material tube wall is low, and it is suitable for medium to high-speed rotation to increase the plasticizing capacity.

Large screws are difficult to rotate quickly to avoid uneven plasticization and excessive frictional heat. For plastics with high heat sensitivity, if the injection screw rotates too fast, the plastic will be easily decomposed.

Usually, screws of various sizes have a certain speed range, generally 40 to 250 rpm.

Pressure-holding section of plastic injection screw
The pressure at which a plastic injection screw pumps through a mold or fills an accumulator depends largely on the configuration of the metering section. The longer and shallower the metering section of a plastic injection screw, the greater its ability to maintain a constant output or maintain the pressure developed at the end of the transition section.

How to pick up the right injection molding screw according to the plastic characteristics

Please feel free to contact us if any questions about injection molding machines` screw and barrel:
[contact-form-7]

Liquid silicone rubber offers numerous advantages for injection molding applications. Its unique performance and versatility make it the first choice in various industries. In this article, we’ll explore the key benefits of using liquid mold silicone rubber, gaining insight into its superior properties and their impact on the injection molding process.

High precision and detail reproduction:

Liquid mold silicone rubber is great for achieving high precision and replicating intricate details. It ensures accurate reproduction of very complex geometries, textures and fine features, making it ideal for molded products requiring exceptional detail reproduction.

Flexibility and Elasticity:

Liquid silicone rubber has excellent flexibility and elasticity, and it is easy to release from the mold without damage. It can effortlessly release molded parts, even those with complex shapes and undercuts, enabling highly automated and intelligent manufacturing production.

Heat and chemical resistance:

Liquid mold silicone rubber has excellent resistance to the high temperatures and chemicals encountered during injection molding. This feature ensures that the mold maintains integrity, dimensional stability and service life, enabling long-term and stable automated production with high consistency and reliability.

Long mold life:

Compared with other mold materials, silicone molds for liquid silicone rubber mold manufacturing have a longer service life. These durable dies withstand multiple production cycles without significant wear or degradation, reducing the need for frequent die changes.

Versatility:

Liquid mold silicone rubber is compatible with a variety of materials used in injection molding, including thermoplastics, thermosets and rubber. Liquid silicone rubber can be overmolded with a variety of other plastics. This versatility allows plastic product manufacturers to use a single silicone mold to produce a variety of products, optimizing production efficiency and significantly reducing mold costs.

Create molds easily:

The user-friendly nature of liquid mold silicone rubber simplifies mold creation. It can be poured or injected into mold cavities, ensuring full coverage and capturing intricate details. The fast curing process enables rapid tooling, reducing overall production time.

Reduce post-molding operations:

The excellent surface finish achieved with liquid mold silicone rubber typically does not require extensive post-molding operations such as polishing or finishing. This simplifies the production process, reduces labor requirements, and increases overall efficiency.

Compatibility with various molding technologies:

Liquid mold silicone rubber is compatible with different injection molding techniques including compression molding, transfer molding and overmolding. This compatibility enables plastic product manufacturers to select the most appropriate manufacturing technology approach for their specific applications, thereby optimizing production efficiency and product quality.

By leveraging the advantages of liquid silicone rubber in injection molding, manufacturers of various plastic products can achieve automated and intelligent manufacturing with high precision, quality and cost-effectiveness. Its superior performance makes it ideal for industries such as automotive, electronics, medical and consumer goods, delivering superior results and driving innovation.

Introduction:

Section 1: The Working Principles of Liquid Silicone Injection Molding Machines

Plastic Preparation:
To initiate the molding process, granular or powdered plastic is introduced into the silicone rubber molding machine’s barrel. The plastic is then melted through a combination of screw rotation and external barrel heating.

Mold Alignment and Injection:
The liquid silicone injection molding machine advances the mold and injection seat, ensuring proper alignment of the nozzle with the mold gate.

Silicone Injection molding:
Pressure oil is introduced into the injection cylinder, propelling the screw forward. As a result, the molten material is injected into the low-temperature closed mold at high pressure and velocity. This stage involves maintaining pressure for a designated period (known as holding pressure) to facilitate cooling and solidification. The purpose of maintaining pressure is to prevent material backflow, supplement the mold cavity, and ensure optimal density and dimensional accuracy. Silicone molds typically have no specific usage limit, as their lifespan depends on usage frequency and potential damage. By employing appropriate utilization and maintenance practices, the longevity of silicone molds can be significantly increased.

Section 2: Understanding Liquid Mold Silicone Rubber

Section 3: Molded Silicone Molding

Section 4: Silicone Extrusion Molding

Conclusion:

Screw slippage is one of most seen injection molding errors for an plastic injection molding manufacturer. So knowing what are the screw slippage reasons and treatment of injection molding machines is very important for every plastic injection moulding engineer and factory or workshop manager.

When the injection screw is difficult to press the material at the feeding port, or the length of the barrel cannot form enough adhesion to convey the material, then the screw will slip. In the stage of screw pre-molding, when the screw rotates in the barrel to convey the material along the direction of the screw and retreats to accumulate the material for the next injection, the screw will also slip. If the screw starts to slip during the pre-molding phase, the axial movement of the screw will stop while the screw continues to rotate. Usually the slippage of the screw will cause the material to degrade before injection molding, and there will be product quality problems such as short shots and extended processing cycle.

Therefore, the reasons for screw slippage are summarized, including: too high back pressure, overheating or overcooling in the second half of the barrel, wear of the barrel or screw, too shallow groove in the feeding section of the screw, improper design of the hopper, lack of material or blockage in the hopper, The resin is wet, the lubricant content in the resin is too high, the particle size of the material is too fine, and the resin used is not cut in a good shape or recycled.

1. Influence of injection molding process parameters

Low temperature in the back section of the barrel is usually the main reason for the slippage of the injection molding screw.

The barrel of the plastic injection molding machine is divided into three sections. At the rear of the feeding section, the material forms a thin layer of molten polymer during heating and compression. The molten film layer is attached to the barrel. Without this thin layer, the pellets are difficult to convey forward. The material in the feeding section must be heated to a critical temperature in order to produce the critical molten film layer. Often, however, the residence time of the material in the barrel is too short for the polymer to reach this temperature. The occurrence of this situation may be due to the small scale of the equipment and the corresponding configuration of smaller barrels and screws. Too short a residence time can lead to insufficient melting or mixing of the polymer, which can cause the screw to slip or stall.

2 simple solutions are proposed for this problem:

a). Add a small amount of material from the end of the barrel for cleaning, and check the melting temperature. If the residence time is short, the melt temperature will be lower than the barrel temperature set point.
b). Observe the molded product. If there are marble spots, black spots or light stripes, it means that the material has not been well mixed in the barrel.

And, according to the usage situation, another solution to the screw slippage is analyzed, and the temperature of the feeding section is gradually increased until the screw rotation and retreat are coordinated. Sometimes it is necessary to increase the barrel temperature above the recommended set point to achieve this range. Setting too high a back pressure can also cause the screw to stall or slip. Increasing the back pressure setting also increases the energy going into the material. If the back pressure is set too high, then the screw may not be able to generate enough pressure to convey the melt forward to overcome the back pressure of the back pressure, and the screw will rotate at a certain position without going back, which will do more to the melt The work and significantly increase the melt temperature, thereby adversely affecting product quality and cycle time. The back pressure applied to the melt can be adjusted by the control valve on the injection barrel.

2. The impact of equipment

If the cause of screw slippage is due to processing equipment rather than process parameters, then screw and barrel wear is likely to be the problem.

As in the feed section, the resin adheres to the barrel wall as it melts in the screw compression section. When the screw rotates, the material leaves the barrel wall after being sheared and conveyed forward. If there are wear areas on the screw and barrel, the screw will not be able to move material forward effectively. If wear is suspected, the screw and barrel should be inspected and the clearance between the two checked. If the fit gap between the screw and the barrel exceeds the standard value, replacement or repair work should be started.

The design parameters of the screw, especially the compression ratio (the depth of the feeding section to the depth of the homogenizing section) play a crucial role in the uniformity of plasticization. A feed section that is too shallow (resulting in a lower compression ratio) will reduce production and cause screw slippage due to underfeeding. Suppliers of various resins generally have recommended optimal compression ratios for injection molding materials. Failure of the non-return ring (one-way valve) can also cause the screw to slip. When the screw is rotating and plasticizing the material, the non-return ring should be in the front (open) position, contacting the retaining ring seat. If the non-return ring is in the rearward (closed) position, or in a position between forward and rearward, the molten polymer will resist passing through the gap between the non-return ring and the ring seat. If you suspect that there is a problem with the non-return ring, it should be replaced immediately.

Note: Because of the different plastic raw materials, the compression ratio is different.

The resin feed hopper can also be the cause of slippage in many injection molding screws. Proper hopper design is key to ensuring consistent material delivery, but is often overlooked. Generally speaking, new pellets of uniform size work well in square hoppers (sudden narrowing at the bottom) with abrupt compression zones. However, this is not the case when regenerative feed is added. The shape and size of the re-grinded pellets are very inconsistent, which will affect the uniformity of the feed. Feed incoherence means that the screw cannot maintain uniform delivery pressure on the melt, resulting in slippage. To solve this problem, and to resolve the size difference between regrind and virgin pellets, try using a round hopper involving a gentle compression zone with a gentle gradient at the bottom.

3. Material uniformity

As mentioned above, the shape and size of the material particles will affect the consistency of the feed. Poor pellet shape can cause poor screw processability, output fluctuations, and screw slippage. The pellets with uniform shape can be packed together more closely in the feeding section of the screw. The closer the pellets are packed together in the screw, the more time the material has to melt and move forward in the screw. Poorly shaped pellets will have more free volume (lower bulk density or more vacuum space between pellets) and feed difficulties, causing screw slippage. Raising the temperature of the rear section of the barrel can make the material start to melt faster, and the melt flow can obtain greater compressibility.

When processing hygroscopic materials such as nylon, moisture can also cause the screw to slip. Improper material drying will significantly reduce the viscosity of the material in the barrel and generate water vapor, making it difficult for the screw to convey the material forward. The moisture content of the pellets should be measured with a hygrometer at the bottom of the drying hopper and compared to the readings recommended by the material supplier.

Above are the screw slippage reasons and treatment for your reference. Please feel free to contact us if you still have and questions or need any help on this topic.

Pipe fitting molds fall under three categories: extrusion, die casting, and forging. Extrusion molds, made from metals, plastics, and composites, are typically used to create smaller pipe fittings such as elbows, tees, and reducers. Die casting molds, made from metals, generate larger pipe fittings like flanges and couplings. Forging molds, also made from metals, create the most common type of pipe fitting.

Each type of mold has its own set of benefits and drawbacks. Extrusion molds are the most affordable and versatile option. Die casting molds are the most durable and can withstand high temperatures and pressures. Forging molds are the most accurate and produce fittings with the lowest level of defects.

The various varieties of pipe fitting molds are designed to perform different jobs. HDPE pipe fitting molds are made to extrude HDPE pipes, while PVC pipe fitting molds produce PVC pipes. P trap molds create a P trap for the drainage system. Some molds are specifically designed to forge fittings, such as elbow fitting molds, tee fitting molds, and reducer fitting molds.

In conclusion, understanding the different types of pipe fitting molds is crucial in selecting the right mold for your project. With the right mold, you can ensure the accuracy, durability, and affordability of your pipe fittings.

PVC Pipe Moulds: A Comprehensive Guide

When it comes to pipe fitting moulds, ABS pipe fitting moulds are a significant type that is widely used in water supply systems. These moulds are designed to join two pipes of different diameters and wall thicknesses, and they feature a specific type of flange known as an ABS flange. This flange connects the pipe to a fixture, such as a toilet or a faucet.

Compared to thread fitting moulds, pipe fitting moulds offer several advantages. They do not require any extra tools for fixing the pipes, and there is no limitation on thread size. This makes them easy to use with any size of pipes, and they are also easier to operate and handle.

Choosing the right pipe fitting mould is crucial for ensuring that your pipe fittings meet all your needs and are of the highest quality. With advancements in technology, pipe fitting moulds are now being designed to perform multiple functions, providing you with a wide range of options to choose from.

Pipe fitting moulds find applications in various industries, including construction, automotive, aerospace, medical, marine, and agricultural. In construction, they are used to create water pipes, drainage pipes, and other piping systems. In the automotive industry, they are used to create fuel lines, brake lines, and cooling systems. In aerospace, they are used to create air conditioning lines, hydraulic lines, and more.

In addition to the industries mentioned above, pipe fitting moulds are also used in many other industries. For instance, the medical industry uses them to create medical tubing, while the marine industry uses them to produce fuel lines and water lines. The agricultural industry uses them to design irrigation systems.

In conclusion, ABS pipe fitting moulds are an essential component in water supply systems, and they offer several advantages over thread fitting moulds. Choosing the right pipe fitting mould is crucial for ensuring that your pipe fittings meet all your needs and are of the highest quality.

When considering the purchase of a pipe fitting mould, it is important to focus on the key factors that will ensure a high-quality end product. One of the most significant considerations is the material from which the mould is made. The mould must be constructed from a durable material that can withstand high temperatures and pressures. Metals, such as steel and aluminum, are the most commonly used materials for pipe fitting moulds.

Steel is preferred due to its solid and durable nature, making it an ideal choice for industrial applications. It can withstand high temperatures and pressures, ensuring a long-lasting and reliable mould. Aluminum is also a popular material for pipe fitting moulds, as it is lightweight and corrosion-resistant. This makes it an excellent choice for applications requiring a high level of accuracy, such as aerospace and automotive applications.

The cavity of the mould is also a crucial factor to consider. The cavity is the space inside the mould where the metal is poured. It must be designed in a way that produces a high-quality pipe fitting. Factors such as the type of metal used, the size and shape of the fitting, and the type of forging or extrusion process used must be taken into account when creating the cavity.

When selecting a manufacturer for your pipe fitting mould, it is essential to choose a reputable and reliable company. While there are many manufacturers in the market, not all are created equal. It is crucial to conduct thorough research and choose a manufacturer with a proven track record of producing high-quality moulds. By doing so, you can ensure that your end product will meet your expectations and requirements.

SPECIAL PROMOTION

The total projection area is determined by adding up the projected areas of the cavities and runners in relation to the parting surface. As such, this value is subject to variation based on the number of items being molded and the layout of the runners. It is important to keep these factors in mind when calculating the total projection area.

Below is the guide for how to calculate the projected area for injection molding. This process is crucial for ensuring that the mold can be properly created and that the final product meets the necessary specifications or help you to pick the right injection molding machines for the mold in production.

Step 1: Determine the parting line of the mold.

This is the separation line between the two halves of the mold and is typically the highest point of the part. It is also where the part is ejected from the mold.

Step 2: Identify the areas that will create undercuts.

Undercuts are areas of the part that create a recess or projection that would prevent the part from being ejected from the mold. Undercuts need to be addressed during the design phase to ensure the mold can be properly created.

Step 3: Calculate the total area of the part.
Measure the length and width of the part and multiply them to get the total area. If the part has any holes or cutouts, subtract the area of those features from the total area.

Step 4: Calculate the projected area of the part.
The projected area is the area of the part that is visible from the direction that the mold will be filled. To calculate the projected area, measure the height of the part and multiply it by the total area of the part.

Step 5: Account for any draft angles.
Draft angles are angles built into the part to aid in its ejection from the mold. The projected area calculation assumes that the part is perfectly vertical, so if there are any draft angles, they need to be accounted for by multiplying the projected area by the cosine of the draft angle.

Step 6: Calculate the projected area of the mold.
The projected area of the mold is calculated by multiplying the projected area of the part by a mold factor, which is typically between 1.5 and 3.

Step 7: Calculate the clamp force required.
The clamp force required to hold the mold closed during injection is proportional to the projected area of the mold. The formula for calculating clamp force is:

Clamp force = projected area of the mold x injection pressure / number of cavities

Where injection pressure is the pressure required to fill the mold and number of cavities is the number of parts that will be produced in each cycle.

Hopper alwalys called barrel.Like screw, it is an important part in plasticizing injection device of IMM.

The barrel is on the periphery of the screw, containing the screw, and the screw rotates in the barrel. The working environment of the barrel is the same as that of the screw. They both work in the environment of high temperature, high pressure, corrosion and greater friction.

Function of hoppers :

The hopper and screw constitute the extrusion system. The barrel is also working under high pressure, high temperature, severe wear and certain corrosion conditions. In the extrusion process, the cylinder also has the function of transferring heat to or from the material.

• The structure of hoppers

Integral barrel

It is processed on an integral blank. This kind of structure can not only ensure high manufacturing assembly accuracy, but also simplify the assembly work, convenient heating and cooling system setting and assembly and disassembly. So, this kind of cylinder requires higher processing and manufacturing conditions.

Combination barrel

It means that a barrel is composed of several barrel segments. In a certain sense, the use of composite drum is conducive to local materials and processing, is beneficial to small and medium-sized factories. But in fact, the processing precision of composite barrel is high.

plastic injection molding machine

In 1980, France produced the world’s largest screw injection molding machine, with an injection capacity of 170kg. From the 1980s to recent years, the development of injection molding machine is mainly concentrated in several aspects: namely, the application of precision automatic control system and various auxiliary equipment in automatic molding; Precision machinery and high performance hydraulic system; Various special injection molding machine development and computer aided design of complex shape parts plastic flow analysis to determine the best injection conditions; Application of various energy saving technologies in injection molding machine.

Working principle of injection molding machine

Injection molding machine referred to as injection molding machine, injection molding is the use of plastic thermophysical properties, the material from the hopper into the barrel, the barrel outside by heating ring heating, so that the material melt, in the barrel is equipped with external power motor drive rotation of the screw, the material in the double action of the screw shear gradually plasticized, melting and homogenizing, when the screw rotation, Material in the groove friction force and shear force under the action of the molten material pushed to the head of the screw, at the same time, the screw in the material reaction backward, so that the head of the screw to form a storage space, complete the plasticization process, and then the screw in the injection cylinder piston reasoning under the action of high speed, high pressure, the storage room of the molten material through the nozzle into the mold cavity, After the molten material in the cavity is kept under pressure, cooled and solidified, the mold is opened under the action of the mold closing mechanism, and the finished product is ejected from the mold and dropped through the ejecting device.

Composition structure of injection molding machine

Injection molding machine according to the injection molding process requirements is a mechanical and electrical integration of a strong machine, mainly composed of injection parts, closing parts, frame, hydraulic system, heating system, control system, feeding device and so on.

plastic injection molding machine

At present, the common injection molding device has single cylinder type and double cylinder type.

Plasticized parts have two kinds: plunger type and screw type. In the process of continuous rotation of the screw, the plastic realizes the change of physical state, and is finally injected into the mold cavity in a molten state. Therefore, the plasticized component is the core component to achieve uniform plasticizing and quantitative injection.

To provide customers with plastic products development, mold design, product manufacturing and injection molding, its products are widely used in every field of life today, such as household appliances, instruments, wires and cables, building equipment, communications electronics, automotive industry, aerospace, daily hardware and so on.

The overall production process of plastic products is: raw material selection – raw material coloring and matching – design casting mold – machine decomposition injection molding – printing – assembly detection of finished products – packaging factory.

Plastic products are made by injection molding or blow molding, so every time you design a sample, you have to open a new mold, and the mold is generally tens of thousands to hundreds of thousands of dollars, so in addition to the raw material price of plastic products, the cost of the mold is also very large. There may be many parts to make a finished product, and each part needs a separate mold. For example, the trash can is divided into: the barrel body — the lid, the liner, the handle several parts.

Generally speaking, the plastic factory refers to the processing of plastic products with plastic raw materials, semi-finished products and finished products, such as MP3 shell, telephone shell, mobile phone shell, computer monitor shell and other plastic accessories. And finished products such as plastic cups, plastic washbasins, plastic buckets, and other daily necessities. Its essence is called plastic processing plant.

Why we need to set mold protection to prevent damage? Beside the injection molding machine itself, the second most expensive piece of equipment we use on a daily basis is the mold. If the molds are damaged, you are not only responsible for the cost of maintenance, but also for downtime and labor costs.If done correctly, the mold can rest on something as thin as a business card. Here are three key components for setting up mold protection on injection molding machines:

1. Starting position of mold protection

When do you reach the point in the mold where you might break when the mold is closed? In the figure above, this point is when the mold touches the guide pin. This is where we want to start mold protection; close the die until there is a small gap between the protrusion of the half die and the other half and there is a risk of damage. Then look at the mold location on the controller to see where you want mold protection to start.

2. Position of die protection end

You need to stop protecting the mold if the mold fully closed. This is called the clamping position or die contact position on the machine. Clamp the die in manual die setting mode until there is no gap between the half dies. For the figure above, the mold position is 0.05 inches. So,we must set the jig position on the machine slightly higher than the actual position to protect it.

3. Speed and pressure of mold preservation

And we need to set suitable speed and pressure for the machine,which is allowed to reach during die protection. In general, we are concerned to slow down the holding of the die during this period and set the pressure low enough so that if something gets in the way of the half die, the die will stop the jig motion and emit a jig alarm.

Don’t forget closing pressure is the most important aspect of die protection Settings!

Following these simple steps, you will help protect valuable mold asset.

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1. The forming parts refer to the parts related to the forming cavity of the moving and fixing parts.
2. The pouring system is to melt the plastic
3. Guide part in the injection mold, the guide part is used to guide the dynamic and fixed mold of the mold, so that the mold can be accurately matched when the mold is closed.
4. Push out mechanism refers to the device that pushes out the plastic parts from the mold after parting.
5. In order to meet the requirements of injection process on mold temperature, the temperature regulating system is needed to adjust the temperature of the mold. General thermoplastic injection mold is mainly designed mold cooling system.
6 exhaust system is in order to form the plastic itself volatile gas out of the mold, often in the parting surface open exhaust groove. For small plastic parts of the mold, can directly use parting surface or push rod and mold clearance exhaust.
7. Supporting parts are parts used to install and hold or support the forming parts and the aforementioned parts of the mechanism.
8. Lateral parting and core pulling mechanism is when some plastic parts have lateral concave and convex shape of the hole or boss, must first put the side concave and convex shape of the flap module or the side of the core from the plastic parts off or out.
The passage through which the basic structure of the plastic injection mold passes from the injector nozzle into the mold cavity, as shown in Figure 1-1, includes the main flow channel, diverter channel, gate and cold hole.

(1) Forming part. That is, the cavity part of plastic products formed directly after mold assembly, including punch, concave die, core, rod or insert.

(2) Mold guide part. It is a part set up to align the center shaft correctly when moving and fixing the die, including the guide post, the pilot hole cover, or the inclined conical piece.

(3) Product launching part. The molding injection product is pushed out from the molding cavity, including the ejector rod, the fixing plate, the pushing plate, the pad, etc.

(4) core extraction part. When injection molding plastic products with pits or side holes are demoulded, core mechanism components for pits and side holes forming, such as inclined guide posts, sliding blocks, bending, etc., should be extracted first.

(5) Specific heating and cooling parts of the mold. It refers to the control system suitable for the temperature of injection molding process of plastic products, such as resistance heating plate, rod and electrical control element; Circulating cooling water pipes are used for cooling parts.

 

(6) The specific supporting part of the mold. Refers to dynamic, fixed die plate, positioning ring, lifting ring, various fastening screws and other auxiliary parts, to ensure that the mold can work correctly.

(7) Pouring melt channel. It refers to the channel that can introduce the melt injected by the nozzle into the mold cavity, which can be usually divided into the main channel, the shunt channel, the bushing (gate) and the cold groove.

(8) Exhaust hole. It refers to the air discharge part in the mold cavity. General small products do not need special exhaust holes, the air in the cavity can be discharged from the gap of the accessories; For molds of large injection products, vent holes must be set up.

Mobile phone shell is usually made of PC(polycarbonate) or PC+ABS material molding, due to the relatively poor liquidity of PC, so the process is usually filled with high mold temperature, high material temperature; The gate used is usually the point gate, and graded injection molding should be used when filling, to find the gate position and the V-P(injection – pressure maintaining) switching position, which will be of great help to solve the gate mark and underinjection fly-side and other anomalies.

The following is the main molding conditions of mobile phone products, introducing the melt temperature, mold temperature, injection speed, back pressure and other molding parameters setting points for attention.

Melting temperature and mold temperature

The optimal setting of molding temperature is related to many factors, such as injection molding machine size, screw configuration, mold and molding product design and molding cycle time. In general, to allow gradual melting of the plastic, lower temperatures are set at the back of the tube/feed area and higher temperatures at the front of the tube. However, if the screw is not designed properly or the L/D value is too small, the reverse temperature setting can also be used.

In terms of mold temperature, high temperature molds provide a better surface appearance, less residual stress, and are easier to fill for thinner or longer forms. And low die temperature can shorten the forming cycle.

Rotation speed of screw

40 to 70rpm is recommended, but it depends on the design of the machine and screw.

In order to fill the mold as quickly as possible, the injection pressure should be as high as possible, usually about 850 to 1,400kg/cm2 and up to 2,400kg/cm2.

Back pressure

Generally, the lower the better, but for uniform feed, it is recommended to use 3 to 14kg/cm2. Injection molding speed, rate of fire and gate design has a great relationship, the use of direct gate or edge gate, in order to prevent sunbeam phenomenon and wave flow mark phenomenon, the application of slower rate of fire. In addition, if the thickness of the finished product is more than 5MM, slow shooting helps to avoid bubbles or dents. Generally speaking, the principle of rate of fire is fast for thin and slow for thick.

Elimination of common defects

a. Air mark: reduce the flow rate of the melt overgate and increase the mold temperature.

b. Undernote: Improve injection pressure, speed, material temperature, mold temperature, improve the amount of glue.

c. Flying edge: reduce the plastic filling pressure, control the V-P switching point to prevent over-filling, improve the clamping force, and check the mold fit.

d. Deformation: Control mold temperature to prevent uneven shrinkage deformation caused by mold temperature difference, through pressure maintenance adjustment.

e. Weld mark: improve mold temperature, material temperature, control the flow of each section to prevent trapped gas, improve the flow front temperature, increase exhaust.

Secondary processing   

The post-processing of mobile phone shell usually includes spraying, color spraying, printing, sandwich printing, electroplating, vacuum evaporation, hot pressing nut, annealing, ultrasonic welding and so on.

By spraying, electroplating and other post-processing methods, the appearance of plastics can be improved, and the friction resistance of plastic surface can be improved. Hot pressing ultrasonic welding and other post-processing methods can add some inserts for easy assembly; Annealing treatment can eliminate the internal stress of products and improve the performance of products.

The number 1 represents PET, or polyethylene terephthalate

Mineral water bottles, carbonated drink bottles are made of this material. Dong Jinshi pointed out that hot water can not be recycled in beverage bottles. This material is heat-resistant to 70℃, which is only suitable for warm or frozen drinks. When loaded with high temperature liquid or heated, it is easy to deform and dissolve harmful substances to human body. Scientists found that after 10 months of use, the plastic could release carcinogens and become toxic to humans. So when you’re done, throw it away. Don’t use it as a water cup, or use it as a storage container for anything else. (The girl in the United Arab Emirates got cancer because she used the same mineral water bottle for 16 months, resulting in the release of carcinogen DEHP.)

The number 2 stands for HDPE, high density polyethylene

Plastic containers for cleaning supplies and bath products. At present, plastic bags used in supermarkets and shopping malls are mostly made of this material, which can withstand 110℃ high temperature. Plastic bags marked with food can be used to contain food. Plastic containers containing cleaning supplies and bath products can be reused after careful cleaning, but these containers are usually not easy to clean, residual original cleaning supplies, become a hotbed of bacteria, cleaning is not thorough, it is best not to recycle.

The number 3 represents PVC, or polyvinyl chloride

Common raincoat, building materials, plastic film, plastic box, etc. Good plasticity, cheap price. But can only withstand 81℃ high temperature. According to reports, this material of plastic products are easy to produce toxic and harmful substances from two aspects, one is the production process is not fully polymerized single molecule vinyl chloride, the second is harmful in plasticizer. These two substances in the encounter of high temperature and grease is easy to precipitate, poison with food into the human body, easy to cause cancer. Currently, containers of this material are used less often to package food. If in use, do not allow it to get hot.

The number 4 stands for LDPE, low density polyethylene

Plastic wrap, plastic film and so on are this material. Heat resistance is not strong, usually, qualified PE wrap in the temperature of more than 110℃ will appear hot melt phenomenon, will leave some plastic preparations that the human body can not decompose. In addition, wrap the food in plastic wrap and heat it. The fat in the food is easy to dissolve the harmful substances in the plastic wrap. Therefore, the food into the microwave oven, the first to remove the wrapping film.

The number 6 stands for PS, polystyrene

This is the material used to make instant noodles in bowls and foam fast food boxes. Heat-resistant and cold-resistant, but not in the microwave to avoid the release of chemicals due to excessive temperature. And can not be used to contain strong acids (such as orange juice), strong alkalinity.

PVC products with a plastic injection molding

PC is a material that is widely used, especially in the manufacture of baby bottles, space cups and so on. In recent years, baby bottles have become controversial because they contain BPA. Experts point out that, in theory, as long as in the process of making PC, bisphenol A 100% converted into plastic structure, it means that the product is completely free of bisphenol A, let alone release. However, if A small amount of BPA is not converted into the plastic structure of PC, it may be released into food or drink. The higher the temperature of the residual bisphenol A in PC, the more and faster the release rate. Therefore, hot water should not be served in PC water bottles. If the container has any fall or damage, it is recommended to stop using, because plastic products if there is a fine surface pit, easy to hide bacteria. Avoid repeated use of aging plastic appliances.