What Materials Can Be Used in Plastic Injection Molding?
It's no secret that the plastic injection molding process is used across a range of industries, and each one relies on a specific material suited to its plastic part.
Choosing a material comes down to the needs of the part, what it’s being used for, and what it needs to withstand. There are an array of different types of materials to choose from — each suited to different needs. In this blog, we’ll discuss some of the more common materials used, why the choice is so important, and what you need to account for, like durability, cost, appearance, and application.
Common Materials Used in Injection Molding
Let’s start with some of the most common materials used for plastic injection molding:
ABS (Acrylonitrile Butadiene Styrene)
ABS is one of the most widely used injection molding materials. It offers a balance of toughness, impact resistance, and rigidity, while also molding with a smooth, glossy finish that takes paint and plating well, making it the most common for consumer products, like electronic housings and small toy parts.
Polycarbonate (PC)
Polycarbonate is known for impact strength and optical clarity, meaning it’s a strong choice when a part needs to be tough and transparent. PC is common in lighting components and safety equipment because it holds up well under high temperatures and can maintain tight dimensional tolerances. This material is on the pricier end compared to other options, and often requires coatings to be added due to it being prone to scratching.
Polypropylene (PP)
One of the most important features of Polypropylene (PP) is its flexibility. Its fatigue resistance makes it ideal for hinges (like flip-top lids on bottles and containers), and it’s often used for medical disposables and household goods. Other important features to note are that it’s lightweight, has strong chemical resistance, and is usually a cost-effective choice.
Nylon (PA)
Nylon (PA) is a solid choice for parts that need to handle mechanical stress. It’s known for its wear resistance and low friction, making it ideal for load-bearing applications, like gears, bearings, or fasteners. It often absorbs moisture, which can affect dimensions and other properties, so this needs to be considered when choosing this material and thinking about what the part will be used for.
Polyethylene (PE)
Polyethylene (PE) is one of the most common plastics in the world. It’s lightweight, affordable, and incredibly resistant to moisture and chemicals. It can come in several grades, including low-density for flexible parts and high-density for more durable parts. You can find this plastic used in packaging, containers, and caps and closures.
Polystyrene (PS)
Polystyrene (PS) is frequently used for disposable products. It’s an inexpensive plastic that is easily moldable while also holding fine detail. You’ll commonly see this material used in cutlery, food containers, and other packaging.
Specialty & Engineering-Grade Plastics
PEEK
PEEK is one of the highest-performing plastics for injection molding, known for extreme chemical and heat resistance and mechanical strength. It has the ability to withstand continuous exposure to high temperatures and harsh environments, making it an ideal choice for products with more intense use. You can specifically find this material used in aerospace plastic parts, medical implants, or industrial parts.
Acetal (POM)
Acetal (POM) , sometimes referred to as Delrin, is known for qualities such as low friction, high stiffness, and dimensional stability. This material can be molded with tight tolerances, making it ideal for parts that require great detail and precision. More common applications include gears, bearings, and conveyor components. This material also resists moisture absorption better than other materials, making it suitable for intense environments.
How to Choose the Right Material
Choosing the material for your plastic part is a step in the process that should be handled with your trusted injection molding manufacturer. Their team will guide you by asking the right questions about your plastic part and narrowing down the best materials in order to ensure your plastic part meets your needs. These are some of the factors you’ll need to consider:
Strength – Will the part face impact, load, or wear over time?
Temperature – Will it be exposed to heat, cold, or sterilization?
Flexibility – Does it need to flex and bend, or stay rigid?
Cost – Higher-performance plastics cost more; determine your budget based on your needs.
Regulatory requirements – Medical, food-contact, or other regulated products may require FDA compliance, USP Class VI, or biocompatibility certification.
And remember, these are all questions your manufacturer will help you answer. They’re the expert on injection molding, and you're the expert on what your plastic part needs to do. Together you’ll develop a production plan, select the right material, and produce a part that delivers.
Conclusion
Choosing the right material is just one step of the plastic injection molding process, but it’s one that is essential to ensuring your plastic part is produced to meet your needs.
With so many choices available, you’ll need to understand your part inside and out. Your manufacturer will be by your side to help determine the right material that meets your strength and temperature requirements, to the cost and regulatory needs.
To learn more about how Camcar Plastics can guide you through this process, fill out our contact form here.
