8 Different Types Of Plastic Molding Services And Their Use

When it comes to manufacturing plastic products, you need the right type of molding service to get the job done. There are various services available, each with its benefits and drawbacks. 

This blog post will discuss five types of plastic molding services and their use in product manufacturing.

Plastic Molding Services 1: Blow Molding

Blow Molding

Define

Blow molding is a molding method for making hollow plastic products. Using gas pressure to blow rubber blank closed in the mold cavity into hollow products is a secondary molding technology. It uses air pressure to shape molten plastic into the desired shape.

Process

The plastic resin is heated to a molten state, then injected into a mold cavity. Compressed air expands the plastic and shapes it in the desired form. Finally, the product is cooled and removed from its mold for a final inspection.

Applications

This method is most effective when producing hollow objects such as bottles and containers. It’s also more cost-effective than other molding processes since fewer materials are needed to complete the job. Blow-molded products are typically lightweight, durable, and suitable for repeat usage.

Advantages

Blow Plastic Molding

Blow molding can produce products with very small wall thicknesses, which cannot be produced by injection molding.

Plastic Molding Services 2: Injection Molding

Plastic Injection Molding

Define

Injection molding is a method of making parts by injecting material into a mold and is one of the most widely used plastic molding processes. It involves forcing molten plastic into pre-made molds to create products with precise shapes and sizes.

Process

First, the plastic is put into the hopper, and then the plastic is heated. It passes through a long chamber with a reciprocating screw. After that, it is softened into a fluid state. The nozzle is located at the end of the chamber through which the fluid plastic is forced to cool, closing the mold. As the plastic cools and cures, the plastic parts come out of the plastic injection molding machine.

Applications

Plastic Molding

The advantage of this method is that it can produce complex parts quickly and with high accuracy. Injection molding is also cost-effective because it requires minimal raw materials and can simultaneously produce large quantities of the same product.

Advantages

Injection molding is capable of creating intricate parts with high accuracy and repeatability. It also offers a faster cycle time than other plastic molding processes. In addition, the low cost per part makes it attractive to many manufacturers.

Plastic Molding Services 3: Compression Molding

Compression Molding

Define

Compression molding is a process similar to injection molding, but instead of using molten plastic, it uses pre-heated and partially cured thermoplastics. The materials are molded into their desired shape by applying pressure with two or more molds.

Process

Plastic molding powder and other materials are added to the mixture to produce special qualities. When the mold is closed and heated, the material is hardened to form its desired shape. The temperature, pressure, and length of time used in the process depend on the desired result. This is a cost-effective way of producing complex shapes requiring dimensions accuracy.

Applications

Compression molding is commonly used to make car parts, electronic components, medical devices, and more.

Advantages

The cost of compression molding equipment is low, the mold structure is simple, and the manufacturing cost is usually lower than that of injection molding. The shrinkage rate of the product is low, and the repeatability is good.

Plastic Molding Services 4: Extrusion Molding

Plastic Extrusion

Define

Plastic extrusion is a mass-production process in which raw plastic materials are melted to form continuous profiles. It is a continuous process that involves passing molten plastic through a mold to create a product with a uniform shape and size.

Process

The process is similar to injection molding in that the dry plastic is first placed in a hopper and fed into a long heating chamber. At the end of the chamber, the material is pressed out of a small opening, or mold, to the desired shape of the final product. After the plastic leaves the mold, it is placed on a conveyor belt to cool. Blowers are sometimes used in this process to help with cooling.

Applications

It is best used to create long, straight parts with consistent wall thickness throughout the length. This process is relatively costly and can produce products of varying strength. The extrusion process is commonly used to manufacture thin films, continuous sheets, tubing, profiles, bars, coatings, filaments, wires, and cables.

Advantages

Extrusion molding can create a product much longer than in a section. Such as various sections of a hollow tube, the length can be cut according to the need and high production efficiency.

The disadvantage is that the mud has a large plasticity; the binder added in the mud number, thus increasing the products’ firing shrinkage, reducing the products’ density.

Plastic Molding Services 5: Rotational Molding

Rotational Molding

Define

Rotational Molding makes plastic parts by rotating molds in an oven while pouring molten plastic into them. This ensures that the plastic covers all surfaces evenly, resulting in a strong product with an even wall thickness.

Process

The Rotational Molding process first adds raw plastic materials to the mold. Then the mold continuously rotates and heats along two vertical axes so that the plastic raw materials in the mold, under the action of gravity and heat energy, are gradually coated evenly, melted, and attached to the entire surface of the mold cavity, molding to the required shape, and then cooling and shaping, demoulding, and finally get the product.

Applications

Rotational Molding is often used to make large hollow parts with complex shapes that require a thinner wall thickness than that injection molded parts. It provides an inexpensive way of creating durable products with minimal waste and high accuracy.

Advantages

Rotational molding parts without internal stress, not easy to deform, no joints, high strength. It is suitable for manufacturing large and super-large products.

Plastic Molding Services 6: Plastic Thermoforming

Thermoforming

Define

Thermoforming is a process that involves heating plastic sheets to make them pliable before they are pressed into a mold.

Process

It is a special plastic process in which thermoplastic sheets are processed into various products. The sheet is clamped on the frame and heated to a softened state. Under the action of external force, it is made close to the mold surface to obtain a similar shape to the mold surface. After cooling and shaping, the finished product will be trimmed. This process is also used in rubber processing.

Applications

In recent years, new advances have been made in hot forming, such as the continuous production technology from extruded sheets to hot forming.

This method creates items with complex shapes, such as packaging trays and boxes. Thermoformed products are lightweight and have high impact strength, making them ideal for applications exposed to frequent shocks or impacts.

Advantages

Thermoforming offers cost savings because it can use thinner plastics, which reduces material costs. It also offers a higher degree of accuracy and faster production rates than other plastic molding processes. Additionally, thermoformed products are stronger and lighter in weight than injection-molded parts.

The process is also very flexible in terms of the types of materials that can be used. This allows for products with different characteristics and properties, such as heat resistance or enhanced durability.

Plastic Molding Services 7: Vacuum Forming

Vacuum Forming

Define

Vacuum forming is a plastic molding process in which heated plastic is forced onto the surface of a mold by a vacuum. The main principle is that the flat plastic sheet is heated and softened, then absorbed on the surface of the mold by vacuum, and formed after cooling.

Process

The Vacuum Forming process begins by heating a sheet of plastic until it is soft and pliable. The heated plastic sheet is then clamped onto a mold, typically made of metal or wood. A vacuum is applied to the mold, which draws the softened plastic down against the surface of the mold. After it cools and hardens, the molded product can be removed from the mold.

Applications

Vacuum forming is ideal for making parts with complicated shapes or thin walls, such as medical equipment, toys, and automotive components. The process is relatively low-cost and has a fast production rate, making it ideal for prototyping and mass production.

Advantages

The molding process can save materials; products are lightweight, convenient for transportation, have good sealing performance, and meets the requirements of environmental protection and green.

Plastic Molding Services 8: Pultrusion

Pultrusion

Define

Pultrusion is a process for producing continuous lengths of plastic-based composite materials. It is similar to extrusion, but the reinforcements are pulled into the die instead of being pushed through it.

Process

The process of pultrusion can be briefly divided into three steps: wetting, forming, and curing/cooling.

The Pultrusion process begins with reinforcing fibers (such as glass or carbon) impregnated with a thermosetting resin. The wet fibers are then pulled through a die, which shapes the material into its finished profile. After the material is shaped, it is cured at high temperatures to form a continuous length of reinforced plastic composite material.

Applications

Pultruded products can be used in various applications, such as structural supports, electrical poles, and handrails. The process is ideal for producing high-strength, lightweight materials with a smooth surface finish. Additionally, the continuous lengths of material can be cut to any desired size or shape. This makes it an ideal solution for applications where custom shapes are needed.

Advantages

The advantages of pultrusion include a high utilization rate of raw materials, high production efficiency, and stable quality. The extrusion molding technology is automatic or semi-automatic assembly line production, can achieve continuous production, and extrusion speed can reach 10m/s.

Author

Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.

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