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Plastic injection mold structure

There is no doubt that plastic injection is the best way to manufacture plastic parts. It is further classified categories depending on the features like mold structure, tool steel, mold opening, SPI standard, part volume, and the feeding system.  Choosing the right old is important as it directly impacts the costs and product quality.

Injection molding is a technique that is mostly used to produce a high volume of complicated plastic parts. First, the material is heated to its melting point and then pushed in an injection port under high pressure until the cavity is filled.

Designing plastics parts is not an easy task as it depends on many factors. First, the plastic parts design should produce a final product that works as intended. Also, the parts produced should be able to integrate during assembly.

Let us look at the mold structure into fine details.

2K Mold

2K mold also popularly known as two-shot involves processing two different polymers. Also, it can be processing two different colors using the injection molding process. Furthermore, this is the best technology that enables the integration of several functions to an injection molded product.

The main advantage of using the 2k molding structure is that the polymer is injected when it’s still hot before shrinking. So it prevents the risk of burrs formation on the second component. Also, good molecular adhesion is enabled following the virginally clean surface.

The cycle time gained is yet another significant advantage. It makes the process constant and without the need for manual insertion. So the first component has no risk of getting damaged.

Insert Mold

Insert molding structure involves embedding a ceramic, plastic, or metal part in plastic to improve the product structure. This is a widely used plastic design in cooking ware, automobile, knobs, devices, household equipment, electrical components, and instruments.

Insert molding is good especially when it comes to reducing the weight and the size of the component. Besides that, insert molding reduces labor and assembly costs. Another advantage of using insert molding plastic parts design is the enhanced flexibility, reliability, and improved part strength.

Insert molding and injection molding do not have a big difference as both use the same injection molding machine. The molten raw material is injected into a plastic mold and then solidified b the use of cooling systems. Furthermore, insert mold also uses similar materials to injection molding. For example, it uses the same mold structure, same mold steel, and the same molding machine.

Over Mold

Over molding referrers to the process by which, a secondary material is molded onto a rigid plastic material using pressure, heat, and liquid silicone. TPE over-molding forms a strong bond between the TPE materials if properly selected. So it will be suitable for endues in its preferred environment.

Nowadays you do not need adhesives or primers to form a strong bond. The most important advantage of using over-molding is that it improves the functionality of the product and the overall aesthetic design. Besides, man’s different colors can be created by the over-mold structure.

Unscrewing Mold

If you are looking for high quality threaded parts and complex plastic shapes then the unscrewing mold is the most suitable technique. Unscrewing mold is usually used to produce a large number of threaded plastic parts for the following items.

  • Cosmetics packaging
  • Bottle caps
  • Shampoo bottles
  • Container lids
  • Consumer goods
  • Sprinkler heads
  • Automotive parts
  • Nuts and bolts
  • Pharmaceutical parts

Unscrewing mold is the best plastic part design for making such parts that cannot be made using the other methods. Unscrewing mold machines operate at a high speed so as it can produce many units at a low cost.

Plastic injection mold structure

Thermoforming mold, cast mold, and blow mold structures are very simple. Conversely, the injection mold, transfer mold, and pressure mold are very complex

Molding parts: punch, die, forming the core. These are used to mold the products on the outside, inside and on the side hole, thread parts, and side concave.

Supporting fixed parts: they include a fixed plate, mold base plate, pad block, supporting plate, and support pressure.

Pull out core parts: slider, inclined pin. Products are demanded b opening the mold out to extract the activity of the core. 

Guide parts: Guide sleeve, guide column sleeve. They are used to determine if the push mechanism movement or mold.

Push out parts: push tube, push block, push-piece ring, push plate, push rod fixed plate, and pushrod. These are used to make products remolding. Visit this site to learn more about plastic parts design.


The plastic injection mold comprises of man parts that allow it to produce the most complex plastics. The mold structure is further divided into parts such as the unscrewing mold, over mold, insert mold, and 2k mold. Besides, the plastic injection mold structure is further divided into parts such as molding parts, guide parts, push out parts, supporting fixed parts, and pull out core parts.

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