Choosing the Best Plastic for Injection Molded Parts

Injection molding is often used for small parts or components, or those with complicated designs and intricate details. Just like thermoforming, choosing the right thermoplastic is key to getting the best results for your final product. To help you determine the right plastic to get the characteristics you need, our injection molding company in North Carolina is sharing some of the factors you need to consider and the qualities the most common thermoplastics offer.

Choosing the Right Thermoplastic for Injection Molding

Injection molding is used to manufacture a massive variety of products, from toys and tools to medical devices and electronics. Not only does every plastic product have different qualities necessary, but often, the individual components within the product need to suit certain needs. That's why its so important to consider the characteristics and qualities you need your component to have.


Will this component bear weight within the overall finished product or placed under stress? While most thermoplastics are durable, some can bear more weight than others, such as polypropylene can bear more weight than acrylic, generally.

Temperature Resistance

If your plastic is used in commercial freezers or under the hood of a car, you need to consider how the thermoplastic will perform under extreme highs or lows in temperature.

Electrical Conductivity

Will the injected molded part require high or low electrical conductivity. Thermoplastics used in automotive manufacturing or telecommunications may be more likely to need higher conductivity than one used in material handling.

Impact Resistance

Will your injection molded part be subject to impact, whether hit by a projectile, knocked around, or dropped? Choosing a thermoplastic with high impact resistance will make it less likely to break or crack.

Qualities of Common Thermoplastics Used in Injection Molding

Just like in thermoforming, once you know the qualities needed from the component, you'll be able to choose the ideal thermoplastic.


ABS is frequently used in both injection molding and thermoforming because it's impact-resistant, chemical resistant, and temperature resistant. In addition to these factors, it's also an affordable material that's also light weight and easy to fabricate and mold, making it a clear choice for a variety of products. ABS is often used to make car parts, kitchen appliance pieces, golf club components, and even musical instruments and LEGO bricks.


Polypropylene has a low density, so it's incredibly flexible and lightweight, and it offers excellent thermal, chemical, and electrical properties, so it can be used in vehicle parts, consumer goods, telecommunications, and electronics. It's also a food-safe and medical-safe plastic, so it can be used in food packaging and medical implants and tools. These features, combined with its low cost and ease of fabrication make it a common polymer in injection molding.

High Impact Polystyrene

High impact polystyrene is an amorphous thermoplastic that is made from a blend of crystal styrene and rubber. Its properties not only make it  resistant to impact, it molds easily, even in microplastics and parts that require incredibly detailed lines and varying thickness. HIPS is often used for high volume orders of injection molded components, such as plastic disposable cups and cutlery and bicycle components.

High Density Polyethylene

High density polyethylene (HDPE) is used in everything from shampoo bottles to artificial joints. It's pliable and flexible with excellent dimensional stability, so it holds its shape easily but can also stand up to impacts, chemicals, abrasion, and moisture. The tensile strength of the material means it can also be used as a composite in rope, cable, and even fabrics.

Call Us for a Free Quote on Injection Molding

At Advanced Plastiform, Inc., we have an experienced design and engineering team who can help you determine the right materials to fabricate your custom plastics. With a wide variety of materials, low per-unit costs, and fast lead times, you can feel confident that you'll get the high-quality, durable plastics you need when you need them. We work with all types of industries and companies through the Southeast and Mid-Atlantic states, including North CarolinaSouth CarolinaPennsylvaniaMarylandTennesseeGeorgia, and Virginia.

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