While not directly related to tool design, it’s important to note injection molding at elevated temperatures is particularly susceptible to moisture. Materials must be completely dry prior to processing or failure could occur even when the most accurate tools are used.

Materials used in injection molding are plastics, specifically thermoplastics. There are hundreds of thermoplastics, but the most common thermoplastics used in injection molding are:

The Tg and Tm temperatures of PAEK plastics don’t vary greatly, yet even the seemingly minor differences can impact critical properties of an injection-molded part, including:

The blog “Materials Used in Injection Molding” provides a comprehensive overview of the various materials suitable for injection molding processes. The author effectively discusses the properties and applications of common plastics, such as ABS, polypropylene, and polycarbonate, highlighting their strengths and limitations. This information is crucial for professionals in the industry who need to make informed decisions about material selection for specific applications. Thank you for sharing this valuable resource, and I look forward to more informative posts that delve deeper into material science and its impact on manufacturing!

PEEK material falls within the family of semicrystalline thermoplastics known as Polyaryletherketones (PAEK). Polymers within the PAEK plastics classification all have high-temperature stability and excellent mechanical strength. Key differences appear in the temperatures at which the polymers’ textures change — the glass transition temperature (Tg) and melt temperature (Tm).

In short, Tg correlates to the temperature at which a solid, glassy polymer transitions to a viscous, pliable state. Tm refers to the temperature at which the structured molecules of crystalline polymers become random chains of molecules (or, amorphous) — essentially, the thermoplastic begins to melt.

Some other common materials used for injection molding include polycarbonate, nylon, acrylic, and polyoxymethylene. Each of these materials have their advantages and disadvantages, which is why, when determining which material to work with, you need to think of how the final product will be used. Will it need to be food-safe? Does it need to be heat tolerant? UV resistant? These are some of the things you need to consider before deciding which material to use.

Myriad considerations go into the final decision. It requires input from an experienced injection molding partner such as Kaysun, and guidance like that which you'll find in our white paper, Processing High-Temperature and Engineered-Grade Resins. Click the button below to download your copy of this valuable resource now.

Once you know which material to use, you will be able to decide which material is best for your project.  Specifically, you will need to choose between an amorphous plastic or a semi-crystalline plastic. The main difference between these two families of plastics is how they react to heat.

Amorphous materials shrink or expand less when heated or cooled because they don’t have a sharp melting point, making the process more forgiving and gradual. Unlike amorphous plastics, semi-crystalline plastics have a much sharper melting point and are known to expand or contract a great deal more when exposed to changing temperature extremes.

Mention “high-temperature thermoplastic” and chances are that polyether ether ketone (PEEK) comes to mind. Its high heat tolerance, mechanical strength, and chemical resistance make PEEK resin ideal for many demanding applications including those in the automotive, electronics, aerospace, medical, and other markets. But is it the only choice?

The application of the product will determine the material used. If a product needs to be transparent yet still durable, like an automobile headlight, polycarbonate would be a good choice. What if your product is a container, like a milk jug? Then polyethylene is the type of material you’ll want to use. Polyethylene is often used for food packaging because it is food safe and won’t leach chemicals.

Choosing the right material for your project will help to streamline the process, improve your product’s performance, and reduce costs.

To ensure consistent, defect-free part production using high-heat resins, tooling design must address several key factors:

Thermoplastics are plastics that melt when heated and make plastic injection molding possible. Most of the plastic products used today are created using thermoplastics because of how diverse this material is. Some thermoplastics are very sturdy and rigid, while others are flexible and rubber-like. Some are clear and others are opaque. It is this diversity that makes thermoplastics such an appealing material for manufacturers.

Do you need design-for-manufacturing (DFM) assistance? Or, are you ready for production? We have a full suite of services to offer and a lifetime mold guarantee.

Here is a table of the most common thermoplastic materials used for injection molding with their unique features and most common applications.

For complex applications, there are rarely any easy solutions — and that includes identifying a high-temperature thermoplastic and maximizing its use during injection molding.

I’m making plastic pliers. mostly needle nose pliers. What material should I use, I don’t need strong heat or chemical resistance in the material used. They should not generate static charges, but they should be electrically non conductive.

These three thermoplastic materials are used all the time. They are cost-effective, durable, and can tolerate the stresses of constant use. You likely use products made from these three materials often, if not every day. For example, ABS is the thermoplastic used to make your keyboard and parts of your phone.

Typically, high-temperature resins can be run on conventional injection molding equipment — with one important caveat. The tooling used with PAEK materials must be able to achieve and withstand high temperatures (at least 165℃) in order to process unreinforced and reinforced PEEK, PEK, PEEKK, and other PAEK materials at processing melt temperatures generally ranging from 370℃ to 410℃.