Material Selection

Choosing the right material for your thermoformed part is key to its performance. At SAY Plastics, we’ll help you get exactly what you need through our design evaluation and development process. In Design Evaluation, we’ll work to understand your size, style and structural requirements. Then through consultation and prototyping in the Development phase, we’ll help you determine which plastic composition is right for your project. Here’s a short explanation of how that choice is made.

There are two basic types of plastic: thermosetting, which cannot be re-softened after being subjected to heat and pressure; and thermoplastic, which can be repeatedly softened and remolded by heat and pressure. Thermoforming/vacuum forming uses thermoplastic sheet. The plastic sheet is heated to make it pliable, then placed into or over a mold. The air between the plastic and the mold is removed by vacuum, enabling our parts to meet close tolerances and incorporate a wide variety of design features.

Performance Benefits of Thermoforming

There are quite a few different plastic compositions commonly used to make thermoformed plastic parts. Depending on the chemical content of the plastic, it will have particular characteristics like hardness, flexibility, and the ability to resist fire, weather, impact and shock.

SAY Plastics works with industry standard and specialty materials, including: ABS, ACRYLIC, HIPS, HDPE, HMWPE, PP, PC, PVC, FR materials, Paint Replacements, Exterior UV, Alloys, and Low CTE.

Here are the primary characteristics of commonly used thermoplastics:

ABS (Acrylonitrile-Butadiene-Styrene)

ABS is tough and impact-resistant. It’s easily decorated, but without additives, it does not resist fire or sun damage well.


Acrylic is more subject to damage from impact. It is versatile in applications where appearance is important, because it can be made transparent and/or high gloss. It is UV resistant.

HIPS (High Impact Polystyrene)

HIPS is commonly found in Point of Purchase displays. It offers low cost, is easily decorated, and is readily available.

HDPE (High Density Polyethylene)

HDPE is an inexpensive, very durable material, offering high chemical resistance. It is easily recyclable.


Has good impact resistance, but is susceptible to scratching without an added coating. Polycarbonate is heat resistant and has good design properties.

PVC (Polyvinyl chloride)

PVC is durable with inherent flame resistance. It also offers good chemical and corrosion resistance.

Getting the Best

A significant advantage to using thermoplastic parts is that it’s possible to combine materials, creating an alloy with the best properties of each. By identifying the characteristics needed in a given part and then selecting the plastic or plastic alloy that provides those characteristics, manufacturers are assured of the performance they need, at a lower cost for materials and tooling.