Injection Molding Materials: Top 10 Choices for Every Industry

Injection molding is a manufacturing process that uses a machine to inject material into a mold. The mold is then heated until the plastic solidifies, producing a finished product.

Plastic injection molding is commonly used to make products such as bottles, cups, toys, medical and automotive parts. In this article, we will discuss the 10 most popular materials used for injection molding, how they compare, factors to consider when choosing a material, and tips for selecting materials.

We will also provide some tips on how to choose a factory when outsourcing your injection molding needs.

Injection molding is a mass-production manufacturing process. It is favored by manufacturers for its ability to produce high-volume, durable, and cost-effective parts.

However, the performance and efficiency of the final product depend largely on the material selected. Understanding the material type and its specific properties is critical to creating products that meet industry standards and application needs.

Due to the characteristics of the material, different injection molding material selections can directly affect the quality, durability, and functionality of the molded product.

For example, products that are frequently exposed to high temperatures require materials with strong thermal stability, while everyday consumer products may prioritize cost and aesthetics.

To make the best material selection, consider key factors such as the material’s mechanical properties, cost-effectiveness, and the specific application requirements of the product.

Injection molding materials fall into three primary categories:

Thermoplastics: These materials are recyclable and versatile. Common examples include polypropylene (PP), acrylonitrile butadiene styrene (ABS), and nylon (PA).

They are one of the most commonly used materials because they are easy to process and recyclable, which helps control costs. This, coupled with their versatility, makes them one of the most commonly used materials.

Thermosetting Plastics: Thermosets are a type of plastic that hardens when heated. This type of plastic is often used to make products such as automotive parts, electrical components, and cookware.

These materials, such as phenolic resins and polyurethanes, are known for their resistance to high temperatures and mechanical stress, making them ideal for harsh environments.

Thermoplastic Elastomer: TPE is a polymer material with the combined properties of rubber and plastic.

Compared to regular plastics, TPE offers several advantages. It has high elongation and rebound rates. It resists permanent deformation under stress and maintains flexibility at low temperatures. These properties make it less likely to crack or break.

We can use TPE for various molding processes, such as injection molding, extrusion, and blow molding. During production, any waste materials can be recycled and reused. This reduces costs and saves energy.

Injection molding material selection involves determining the substance that meets the needs of a specific industry. Here are ten of the most commonly used materials, their applications, and key properties.

There are many types of nylon, and different types have different properties. Common types are nylon 6, nylon 66, and nylon 11. Of all the nylon grades, nylon 6 has the lowest modulus. It is valued for its high strength, thermal stability, and wear resistance.

Nylon is often used to make products such as automotive parts, gears, and textiles. Products made from nylon can usually withstand mechanical stress while maintaining dimensional accuracy.

Polypropylene is a colorless, odorless, non-toxic, translucent solid substance that is one of the most affordable and chemically resistant thermoplastics. It is known for its high strength, rigidity, and chemical resistance.

PP is often used to make medical devices, consumer products, and packaging. Its light weight and excellent moisture resistance make it a preferred material for high-volume production.

ABS is a thermoplastic material used in many injection molded products. It is a popular material choice for electronic housings, toys, and automotive interiors. It is known for its impact, heat, and chemical resistance.

Manufacturers favor ABS because it combines easy formability and a glossy surface that allows it to produce beautiful and functional products.

The full name is polyethylene, which is known for its low density, high strength, and low moisture absorption. PE is often used to make products such as pipes, fittings, and bottles. Its excellent flexibility and chemical resistance make it ideal for products exposed to harsh environments. Polyethylene has high ductility, which ensures durable and leak-proof designs.

Polycarbonate is a high molecular weight polymer. It is known for its high strength, rigidity, and transparency. PC is often used to create products such as medical, optical lenses, safety equipment, and electronic components. This material balances impact strength and aesthetics, ensuring reliability in critical applications.

Polyoxymethylene is a linear polymer with no side chains, high density, and high crystallinity. It is a white or black plastic granule with high hardness, high rigidity, and high wear resistance. It is mainly used in products that play a skeleton role, such as gears, bearings, automotive parts, machine tools, and instrument internals.

Acrylic, also known as organic glass, is often used as a substitute for glass. It has high transparency, 92% light transmittance, good weather resistance, easy machining, and can be adhered to chloroform.

Its UV resistance, optical transparency, and surface hardness make it an excellent substitute for glass in applications that require lightweight transparency.

TPU is a multifunctional elastomeric plastic with unique properties. The key to its versatility lies in its highly customizable hardness. Thermoplastic polyurethane can be as soft as rubber or as hard as hard plastic. Its appearance and texture are equally varied. It can be transparent, colored, smooth to the touch or textured. It is an ideal choice for medical equipment, hoses, footwear, wires and cables.

TPR has easy processing performance, good coloring performance, and can adjust the physical properties to a suitable formula, providing a wide range of product design space; the mechanical properties are comparable to vulcanized rubber, but no vulcanization cross-linking is required.

It has excellent tensile resistance, with a tensile strength of up to more than ten MPa and an elongation at break of up to 1500%.It is commonly used in gaskets, seals and handles, providing a soft touch and excellent durability.

General polystyrene resin is a non-toxic, odorless, colorless transparent particle, a glass-like brittle material, and its products have extremely high transparency, a light transmittance of more than 90%, good electrical insulation performance, easy coloring, good processing fluidity, good rigidity and good chemical corrosion resistance. The disadvantages of ordinary polystyrene are brittleness, low impact strength, susceptibility to stress cracking, poor heat resistance and inability to resist boiling water.

Choosing the right plastic material is very important for injection molding. Material selection is not only about understanding the requirements, but also about evaluating the options. The strength, hardness, wear resistance, temperature range, and chemical stability required by the product must be taken into account.

When selecting injection molding materials, you need to consider the required material physical and mechanical properties, such as strength, flexibility, impact resistance, hardness, wear resistance, and chemical stability. Different plastic material products have different properties to ensure their performance in the intended application.

When selecting injection molding materials, you need to consider environmental factors. For products exposed to extreme temperatures, the selected materials need heat resistance and thermal stability to ensure that the manufactured products have good durability in specific environments.

For industries such as healthcare and automotive, compliance with FDA standards, UV stability, or flammability ratings are often required to meet safety and regulatory standards. This is an industry must.

Different materials have different prices, so you need to balance material costs with performance requirements to ensure that the project is profitable without compromising product quality.

If the required plastic product needs to have a specific appearance and texture, it is necessary to choose the appropriate injection molding material. Some plastic materials have good surface quality and texture, while others are not very suitable for manufacturing products with high aesthetic requirements.

Choosing the right injection molding material requires strategically evaluating material properties, application requirements, and manufacturing costs to select the best material for your specific project.

Understanding the key properties of injection molding materials will allow you to properly select the right material. Material properties directly impact the performance, durability, and functionality of your final product. Here are the material properties you need to know:

The melt flow rate (MFR) indicates how easily a material flows during the injection molding process. A higher MFR means that the material flows more easily and is ideal for products with thin walls or complex geometries.

However, low MFR materials may be better suited for heavy-duty applications. The reason is that low MFR materials provide better structural integrity.

Tensile strength is a measure of a material’s tensile strength. Parts that need to withstand mechanical stress or require long-term durability generally choose materials with high tensile strength. Common high-strength materials include nylon and polycarbonate.

Thermal stability is a measure of a material’s ability to withstand high temperatures without degradation. Parts that are exposed to high temperatures for long periods of time, such as automotive or industrial parts, are particularly dependent on this material. Materials such as polyetheretherketone (PEEK) offer excellent thermal stability.

Choosing a material for injection molding requires balancing advantages and limitations. A side-by-side comparison can help determine the best option for your application. Here is a summary of material properties, strengths, costs, and applications.

Choosing the right material is more than just identifying the best or cheapest option. It is a strategic approach to consider multiple factors and choose the best injection molding material.

Based on the product’s operating environment, loading conditions and aesthetic preferences, the material and the intended use of the product are optimized.

Choosing to work with professional suppliers or manufacturers, you can explore material options that meet performance and budget constraints with experts to get the best results for your project.

Evaluate key indicators such as modulus, tensile strength and impact resistance of the selected materials to ensure that the material is suitable for your project.

Choosing the right injection molding material can significantly impact your product’s success. By understanding the properties and applications of popular materials, you can ensure optimal performance and cost-efficiency.

Contact Great Light today for expert material selection advice and customized injection molding services.

Polypropylene (PP) is often the most affordable and versatile option.

Polycarbonate (PC) and thermosetting plastics are ideal for high-heat applications.

Yes, many thermoplastics, such as Polypropylene (PP), can incorporate recycled content.