Plastic Molding Company: Introduction to Molding Process

Nov 23, 2020

 Plastic Molding Company: Everything About Molding Process 

All plastic materials demand a molding process, whether a small or a large Plastic Molding Company needs to ensure high-quality molding. In addition, there is the ever-increasing use of plastics from automobiles to synthetic human body parts.

The molding process involves shaping raw liquid plastic, pellets, sheets, or powder into different simple and complex shapes using rigid frames known as mold or matrix.

Moreover, the pellets are loaded into the hopper, a part of the mold where they are heated until they are in a soft, molten, or semi-liquid state.

You May Also Read: Plastic Injection Molding Factory: Modern Vs Conventional Molding

Moreover, within the heating cylinder, a screw mixes the molten material and pushes it to the cylinder's end. The screw controls the speed and pressure of molted material.

Also, the material is allowed then to cool down and set; then the mold is opened or removed the plastic products are ejected automatically out of the machine. Also, the control of thermal processes is vital in the production of high-value plastic products.

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Plastic Molding Company: Techniques of Molding Processes

There are several methods used to prepare plastic. Below is an overview of the process!

Injection Molding process

It is used to make custom, intricate, plastic parts in various large scale production by injecting plastic material under high pressure into the mold. In addition, the thermostat heats the product faster, cheaper, and form a better product. The mold is allowed to cool, and a plastic part is released when the mold is opened.

Moreover, the sizeable sized machine produces significant parts like dashboards or bumpers, and small machines produce specific parts such as switches, surgical devices, or plastic bottle caps. Products have good dimensional accuracy.

Injection Molding

There are many types of injection molding.

The Rubber Injection Molding.

The rubber is directly vulcanized from the barrel to mold. It happens in intermittent operations, but the molding cycle is short.

Plastic Injection Molding

Molten plastics are used in molds obtained by the cooling process. A particular injection molding machine is used to make plastics.

Mold Injection Molding

In this case, two silicone rubber materials combine into a mixture and produce final parts in one day, such as seals, connectors, cables, medical devices, kitchen devices, and infant products.

The final shape of the product requires no other finishing processes. It is possible to create many details using the Injection molding process. 


Plastic sheets and temperature is used in a mold. There is a variety of thermoforming plastics in colors, thickness, and finishes.

Also, different types of molds are used to create3D products: disposable cups, plates, lids, trays, fridge liner, and auto parts. Tooling cost is low, medium production rate. Thermoplastics can be recycled again and again.

Over molding

In this method, two materials combine to form one object or one part.

There are two types of material used in over-molding. One part is known as a substrate, and the other is over-molding material. Substrate materials are plastic, metal, glass, etc.

Over molding material include rubber and thermoplastics. It eliminates complicated processes and reduces the manufacturing cost, and gives the product a firm grip, specific features. 

  • Casting

A liquid is poured into a specifically designed mold cavity allowed to cool and solidify. The hardened part is known as casting. Thus mold is removed from the casting. Heavy machines and beds, and ships are cast into the required size. Dip molding coating process

It is another plastic manufacturing process where a heated metallic structure in a PVC tank is called plastisol. The plastic is separated from the mold part upon cooling medical.

In addition, Plastic covering makes a protective layer as a finishing and smart look. The plastic coating is done around the mold by the cooling process.

Rotational Molding/Rotomodling Process

The rotational molding process was used in 1950 to make the dolls' heads, and in 1960, s rotational molding allows to make large and hollow parts. So, in-mold liquid or powder resin is kept and rotated in an oven, so even wall plastic is created. There is no wastage of material during this process.

Moreover, this method number of products are made like large hollow simple shape containers, car parts, recycling bin, and slides. Tool costs are less as compared to the other methods of molding like injection and blow molds. 

Blow molding process

In this method, machines heat the plastic and inject air like a balloon to make delicate hollow parts of various sizes that shape the mold's walls. Then it is cooled, and when it is hardened, it is ejected from the mold. Bottles, cans, drums, and tanks are produced by using blow molding processes.

Furthermore, it is cheaper, faster, and economical than the injection molding method but more costly than rotational molding. It has a low production rate.

Plastic Molding Company offers Compression Molding

Heated mold melts the plastic or metals to press to make a specific, unique shape and durability. Also, it is cost-effective and efficient. Cooling and removing the extra parts is done as the final steps.

Final parts are strong and durable and are used in different applications. It is used in automotive parts, fiberglass thermosetting resin, household appliances, hood spoilers, and smaller auto parts.

Extrusion Molding

It is a unique process; a die is used in this method, not a mold. A long, uniform, hollow, solid tubular shape with complex with constant cross-section shape is produced as an end product.

So, when the extrusion cools, it is removed from the machine. PVC piping, tubes, straw, dependable rods, wire, cables, strips window frames, hoses, plastic gutters, and straws are included.

Thus, the cost of extrusion molding is low, but the production rate is high because of the simplicity of die and machine.

Spin trimming

The machine trims around the domes or neck of bottles made by blow molding at a higher and efficient speed. There is no leakage from the bottles.

Vacuum molding

Plastic sheets are heated on to a single surface. Original silicone made a mold by a vacuum. This process takes a few days to become a functional prototype. In addition, Plastic sheets are prepared with high-quality fine details. This process is costly for a number of parts.

Compression molding

Preheated material is used in the mold cavity. Moreover, the mold is closed with a plug and then compressed the material. It is used to make flat or curved parts. There is little waste, and it cost low.

You May Also Read: Why Automation of Plastic Molding is Important?

Take Away on Plastic Molding Company

In short, the engineers help you to understand the type of design and product suitable for your needs through the best manufacturing process. 

If you are looking for more information, contact us today. We, SZ-Changhong, are the leading molding company. Therefore, we promise premium quality injection molding, molding designing, and several other services. 

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