Plastic injection molding – methods, technologies

Plastic injection molding is the production of plastic products using a special technology. The advantages of the methods include the ability to reproduce complex shapes with high accuracy. Plastic injection molding methods differ. Several specialized technologies have emerged in recent years. Understanding the advantages and disadvantages of each plastic molding method is important when choosing an option for a specific project.

Advantages of injection molding technologies

• Greater design freedom. The method allows for the creation of an almost unlimited variety of shapes – even complex mesh structures can be realized with high accuracy.
• High volume production. Due to the long service life of the tools used, significant potential advantages are realized in large-scale production.
• Light weight. Significant weight savings are often achieved compared to other materials.
• Finished components. Molded parts are ready for use immediately after production – without any additional processing.
• Diverse material properties. Plastic is characterized by useful properties such as corrosion and chemical resistance, as well as numerous possibilities for improvement through the use of various additives.

Casting methods

The methods involve high-precision production of parts in specially prepared molds. The injection molding technology includes the following stages:

• Filling and closing the mold.
• Holding under pressure using gas, water.
• Cooling.
• Removing from the mold.

These are general stages that differ slightly in each technology. Let’s look at the main types of plastic molding.

Classical injection molding

The technology in which plastic is heated to a molten state, and then, as a result of pressure from a press, takes shape, is in high demand and is used in various segments of industry.

Gas-filled molding

In the process of injecting plastic into a mold, gas, usually nitrogen, is used to create a cavity inside the product. The technology allows you to reduce the weight of the product and the amount of raw materials used. The method is used to produce large-sized or complex hollow products, such as furniture or car parts.

Rotational molding

Rotational molding involves the use of a rotating mold, inside which molten plastic is evenly distributed over the inner surface.

This method allows you to get seamless structures, such as water storage tanks. Rotational molding products typically have a smooth surface and can be easily painted or decorated.

Hot Runner Molding

An advanced technology that improves product quality, reduces waste, and increases process efficiency. In this system, molten plastic is fed into the mold using special heat runner units. Hot runner systems are used in industries that require high-volume production of high-quality plastic products:

• Automotive panels, bumpers;
• Medical syringes, containers, instrument housings;
• Electrical connectors;
• Household appliance components;
• Packaging.

Multi-Component Molding

Multi-component molding is a plastic molding technology that allows the creation of complex plastic products from several different components or materials. This technique is used to improve the functionality and aesthetic properties of products, as well as to improve their mechanical properties.

In the multi-component molding process, several materials are fed into the same mold, which allows the creation of products with different textures, colors, and properties in a single process. This is especially useful in industries such as automotive, electronics, and consumer goods. Examples of such products include toothbrushes with soft and hard elements.

RIM — Reaction Injection Molding

The process involves two main components: isocyanate and polyol. Sometimes reinforcements, catalysts, and other additives are added. Polymerization occurs directly in the mold. The method is widely used to produce large-sized and lightweight products of regular shape.

Micromolding

Plastic micromolding is a specialized molding process that is used to create small parts with high accuracy and detail. This technology is especially relevant in industries such as medicine, electronics, and automotive components, where small but complex components are needed.

In the process of micromolding, molten plastic is injected into a mold with very small dimensions, which allows for the production of products with a high degree of detail and minimal tolerances. In addition, this technique helps to reduce waste and reduce production time.

PIM — Powder Injection Molding

The process involves mixing metal or ceramic powders with a polymer binder. The mixture is injected into a mold under high pressure, where it takes on the desired shape. After molding, the part undergoes a debinding process, leaving only a powder network. The part undergoes a heat treatment, which binds the powder and processes it into a durable part.

PIM allows for the creation of parts with a high degree of complexity, detail, and reduced material waste. This technology is widely used in various industries, including automotive, medical, and electronics.

Reinforced Plastic Injection Molding

Reinforced plastic injection molding is a process in which plastic composites are mixed with reinforcing fibers or particles to improve the mechanical properties of the final product. Reinforced materials can include fiberglass, carbon fiber, and other materials such as minerals or metal particles.

Water-Cooled Injection Molding

This is a technology that is used primarily in casting and molding processes to accelerate the cooling of molten material after it has been injected into the mold. This method allows for effective control of temperature and cooling time, which plays an important role in the quality and properties of the final product.

As you can see, there are several plastic forming methods that are used to manufacture products. Each method has its own advantages and disadvantages, so it is important to carefully analyze the requirements of your project to choose the best approach. Some of these forming methods are ideal for one application, but may be useless for another. If you are interested in injection molded plastics and products made from them, contact our company. Specialists will provide detailed advice and help with the choice of a method for the successful implementation of your project.