Plastics and Injection Molding

Perfecting Plastic Forming Processes

Plastic objects are formed through processes such as compression, transfer, and injection molding. Our EMPDA Plastics Specialty Group focuses on perfecting processes like these for each project our customers bring. Just as there are many different types of plastic, there are a variety of processes to mix and shape the material, since different materials must be worked in different ways. There are also various advantages to each method depending on the type of product that is to be produced. Our experts can help determine the best manufacturing route for your plastic part or product.

EMPDA's Plastics Forming Expertise

Material Selection: Considering physical properties, chemical stability, and processing characteristics to ensure materials meet product requirements.
Mold Design: A professional design team ensures high precision and durability of molds, enhancing product quality and production efficiency.
Temperature Control: Precisely controlling the heating and cooling processes to ensure uniform melting and solidification of plastic materials.
Pressure Control: Setting injection pressure, holding time, and pressure reasonably to ensure the integrity and dimensional stability of the products.
Forming Speed: Optimizing the forming speed to increase production efficiency while maintaining product quality and consistency.

Injection Molding

Injection molding is a low-cost way of making thermoplastic parts in large quantities. Intricate parts can be made to close tolerance with no need for second operations. The single-stage reciprocating screw system is commonly used for the injection molding process it prepares material thoroughly for the mold and is general a faster system. Injection molding of thermosets average 25% faster than compression molding, but requires careful attention. Molds can also be costly and larger volumes are often required for economical operation.

Compression Molding

In compression molding, a specific amount of material in a mold cavity is squeezed by a punch or force. The plastic material is heated until softened, and it flows to fill the space between the force and the mold. The mold is kept closed until the formed piece has had time to harden.

Transfer Molding

Transfer molding is a process where material is heated, loaded into a chamber called a pot, and forced through a sprue into mold cavities. With this, closer tolerances and more uniform density can be held since the mold is enclosed, rather than open like in compression molding.

Blow Molding

Most common for hollow parts, in blow molding a die closes around a liquid plastic tube, is poured vertically, as air is forced into the hollow part of the tube. This forces the plastic to the outer part of the mold.

Film Insert Molding

This process is often used with injection molding. A thin film of plastic, either on a reel (IMD) or a die cut piece (IML), is inserted into an injection molding die and integrated with the part through the injection process.

Rotational Molding

Hollow molds are filled with a resin powder and the molds are heated and rotated, allowing the plastic to stick to the walls of the mold and itself. This is most commonly used for hollow, large, and durable parts.

Overmolding

Typically used for parts that need two different types of plastic (soft/rubber and hard) or two different colors (clear and opaque). The first shot (substrate) is usually covered —partially or fully— by the second shot (overmold).

Insert Molding

Used with metal inserts and injection molding, the insert is placed into the mold, then during the injection process the insert is encased by the plastic.

Vacuum Forming

A sheet of plastic is placed over the male die mold. Through heat, the plastic is vacuumed to take the shape of the mold. This is most commonly used for large, simple parts.

Surface Finishing Processes

Applying a layer of color or protective coating to the plastic part by spraying. either to a wheel or to the surface and through rubbing the surface of the part becomes shiny, or mirror like.

Adding a metallic coating to the plastic surface to enhance its appearance or provide additional protection.

Printing text, patterns, or other markings onto the plastic surface using a screen printing process.

Applying decorative gold or colored foil to the plastic surface using heat and pressure.

Creating a durable and vivid coating on the plastic surface using UV-curable ink that hardens under ultraviolet light.

Carving patterns or text into the plastic surface using a laser beam.

A high-temperature process that transfers designs from a carrier film to the plastic surface using heat and pressure.