5 Incredible Precision Engineering Plastics

Precision engineering plastic
Today’s precision engineering plastics offer superior chemical resistance, higher temperature capability, greater dimensional stability, good wear resistance, and excellent machinability. Below are five of the best precision engineering plastics on the market, able to tackle the most challenging applications in any industry.

PEI (Ultem)

With a tensile strength of 15,200 psi and continuous use up to 340ºF, PEI (polyetherimide) plastic is a lower cost alternative to PEEK. Its long-term creep resistance also makes it a great replacement for metal and other materials in many structural applications. It is also inherently flame resistant, has excellent chemical and hydrolysis resistance, and one of the highest dielectric strengths of any thermoplastic material.

Also known as Ultem®, PEI has outstanding dimensional stability and is easily machined and fabricated. Combined with its mechanical properties, PEI’s processability offers great flexibility and freedom to design engineers. PEI can be found in semiconductor equipment components, medical and chemical instrumentation, aerospace parts, automotive applications, and more.


When an application demands excellent strength and impact resistance, low wear and/or low friction rates, and high thermal resistance, engineers turn to Vespel®. This highly durable polyimide has outstanding creep resistance and doesn’t lose its mechanical properties in extremely high temperatures (up to 500ºF). It is also lightweight, highly resistant to chemical corrosion (including industrial hydraulic fluids, fuels, and solvents), and doesn’t outgas, making it safe for vacuum applications.

Vespel® can easily be machined to achieve complex geometries and tight tolerances, allowing for the creation of designs that would be impossible with lesser materials. From bearings to critical aircraft parts, Vespel® can withstand the harshest operating conditions on the planet.


PEEK is a high-performance engineering plastic with a unique combination of properties that makes it incredibly strong and dimensionally stable both under load and in the harshest environments. PEEK offers high temperature resistance (with a melting point of over 700ºF), high wear and abrasion resistance, outstanding resistance to harsh chemicals and superior creep resistance. It also has high tensile and flexural strength (16,000 psi and 25,000 psi respectively), very low moisture absorption, excellent electrical properties, and is biocompatible. While PEEK’s high temperature resistance can make it difficult to process, in its solid state PEEK is readily machinable by CNC milling machines. It is also available in a variety of grades that offer targeted enhanced properties.

PAI (Torlon®)

PAI (polyamide-imide) is an extremely strong, stiff, dimensionally stable plastic that maintains its mechanical properties at continuous temperatures up to 500ºF. It has the highest tensile strength of any unreinforced thermoplastic (21,000 psi), as well as good wear and radiation resistance, and inherently low flammability and smoke emission. With extremely low thermal expansion and superior creep resistance, PAI is an excellent choice for tight-tolerance applications. It is widely used for bearings and bushings, aerospace components, seals, pump and valve parts, and semiconductor machinery parts.

PTFE (Teflon®)

More commonly known as Teflon®, PTFE is famous for having one of the lowest coefficients of friction against known solids. Pure PTFE is almost totally chemically inert and highly insoluble in most solvents or chemicals, making it the perfect material to store or handle corrosive chemicals. PTFE is also hydrophobic, has high flexural strength, a large operating temperature range (between -328ºF and +500ºF), and high electrical resistance and dielectric strength. It is commonly used for high-friction mechanical parts such as screws and bearings.

For expertly CNC machined parts from precision engineering plastics, call Reading Plastic today at 610-926-3245. We excel at producing the precise parts you need from the most advanced materials!

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