Types of Injection Molding Materials

Waseem Jalal

The materials you choose are critical to achieving the results you want in injection molding. An understanding of the different types of materials available and their properties can have a significant impact on the success of your project. FirstMold Injection Molding Service has shared with us their knowledge of materials to create the products you need, which will be outlined in this article.

Injection molding materials include a wide range of plastics. Each is uniquely suited for different applications. These materials are broadly categorized to help make choosing easier:

1. Standard Thermoplastics

Standard thermoplastics are versatile and suitable for many applications. They offer a balance of properties that make them ideal for general use.

PE (Polyethylene): PE is an exceptionally resilient and durable material with great chemical resistance and the ability to endure significant impact. There is no plastic more commonly used than this one. Its high strength-to-weight ratio and petroleum origin make it an attractive material. Dimensional stability is another benefit; even when subjected to high pressure or temperatures, its components will keep their original form. Since it can be recycled, polyethylene is a fantastic choice for a wide range of uses. Features that set it apart include: impermeability, chemical resistance, and superior electrical insulation.

PP (Polypropylene): The thermoplastic polypropylene (PP) has great strength and elasticity, making it a popular choice. Many automotive parts, electrical components, and packaging materials make use of this material, which is available in both clear and colored varieties. It may be easily shaped and sized via injection molding, and its excellent resistance to moisture makes it ideal for use in high-temperature applications. Beyond being electrically insulating and heat resistant, it is also fatigue resistant. Important characteristics include: resistance to heat, chemicals, and moisture; high impact strength; good flexibility.

PS (Polystyrene): A type of thermoplastic that is both translucent and amorphous. Because of its hardness and high strength, it finds usage in many different contexts. In addition to being gamma radiation resistant, it demonstrates excellent electrical properties. Because it can be injection-molded into a wide variety of forms and sizes, it is a common material for many types of plastic goods, including those used around the home. Claims to fame: see-through nature; hardness and brittleness; and remarkable strength.

2. Engineering Thermoplastics

Engineering thermoplastics are designed for more demanding applications and offer improved mechanical and thermal properties.

PC (Polycarbonate): A transparent thermoplastic with good impact, shatter and stiffness properties. It also has excellent chemical resistance properties. The PC’s transparency makes it excellent for applications that demand visibility of internal components. Its high melting point of 250°C makes it useful for a variety of engineering applications. It exhibits great stiffness and viscosity, making it ideal for items that require high dimensional precision and tight tolerances. Key advantages include shatter resistance, good electrical properties, transparency, and durability.

PA (Nylon): Nylon is a semi-crystalline thermoplastic with high wear resistance, chemical resistance, and toughness. It can be used with other materials to improve its qualities even further. The fiber in the material is robust, but it provides good suppleness to the product. Nylon  is also useful for applications that require tight tolerances. It also provides strong wear resistance with good electricity. Key qualities include rigidity, high strength, and resistance to wear and chemicals.

POM (Acetal): POM, often called Delrin Acetal, is a semi-crystalline thermoplastic with high strength and wear resistance. It can easily be shaped into various shapes using molding methods and has excellent chemical resistance. POM is widely utilized in industrial applications due to its high tensile strength of 75.8 MPa. It is generally robust and resilient, with limited moisture absorption capabilities. Key qualities include wear resistance, strength and durability, and high tensile strength.

3. High Performance Thermoplastics

High performance thermoplastics stand out in environments delivering heat resistance and mechanical durability.

PEEK (polyether ether ketone); PEEK finds use in aerospace and medical fields for its performance, in high pressure and high temperature conditions.

PPS (polyphenylene sulfide); Recognized for its resistance to chemicals and heat PPS is a choice for aerospace components.

4. Thermoplastic Elastomers 

Elastomer (TPE) is an injection molding material that combines the flexibility of rubber with the strength and heat resistance of thermoplastics. It is frequently utilized in place of typical rubber and plastic materials due to its increased flexibility and durability. It has great temperature and chemical resistance. TPE also has exceptional wear resistance, making it a popular material for automobile parts and gaskets. It is available in several grades and is intended for certain uses. Key Features: Flexible, strong, and durable. Tear and abrasion resistant. TPE is widely utilized for grips, handles, seals, power and hand tool components, wires, and cables.

5. Modified Plastics

Modified plastics are tailor made to fulfill performance needs providing customized solutions for applications.

ABS+PC ( butadiene styrene + polycarbonate); ABS+PC blends strike a balance between toughness and heat resistance making them suitable for enclosures and protective helmets.

POM+GF (Acetal + Glass Fiber); POM+GF blends enhance strength and rigidity ideal for demanding parts and gears.

Materials Selection

When selecting the material, for injection molding various criteria must be taken into account. Ensure that the material aligns well with the injection molding procedure and tooling taking into account the products needs like durability, resistance, to chemicals and suitability for various environmental conditions. Next assess the material costs in relation to performance demands and production quantities. You can make informed decisions by consulting injection molding services.

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