A Guide to PAI CNC Machining

Key Takeaways

• PAI offers industry-leading mechanical strength, wear resistance, and high-temperature performance among thermoplastics.

• Its excellent dimensional stability and chemical resistance make it a lightweight alternative to metal in demanding applications.

• PAI is a premium material that requires moisture management and careful cost evaluation before use.

Characteristics of PAI

PAI (polyamide-imide) is an amorphous super engineering plastic with the highest performance of any thermoplastic. It delivers outstanding tensile strength, compressive strength, wear resistance, and impact resistance at temperatures up to 250°C.

Its heat deflection temperature and glass transition temperature both exceed 250°C, allowing it to maintain high strength in demanding high-temperature, high-load environments.

Chemical resistance is also excellent, with broad compatibility across most organic and inorganic chemicals. PAI has a coefficient of thermal expansion comparable to metals like aluminum and stainless steel, giving it the dimensional stability needed to serve as a lightweight metal replacement.

• Exceptional mechanical strength and wear resistance

• Excellent heat and cold resistance

• Excellent dimensional stability

• Electrical insulation

• Excellent chemical resistance

• High performance at elevated temperatures

• Flame retardant

• Excellent radiation resistance

Types of PAI

In addition to the standard grade, PAI is available in specialty grades with enhanced or added properties.

• Standard grade

• Sliding grade

• Glass fiber reinforced grade

• Carbon fiber reinforced grade

Material Selection Notes

PAI absorbs a small amount of moisture. Parts intended for use at 200°C or higher should be dried beforehand, as rapid heating of a moisture-saturated part can cause it to expand. PAI is also more expensive than PEEK, so other materials should be thoroughly evaluated before committing to it.

• Moisture absorption

• Risk of expansion if rapidly heated while moisture-saturated

• Very high cost

PAI CNC Machining at Yumoto Electric

Yumoto Electric manufactures custom PAI machined parts starting from a single piece. We have experience with over 200 materials, including metals such as aluminum alloys, stainless steel, molybdenum, and titanium; and engineering plastics including PEEK, POM, and MC Nylon.

If you’re unsure about material selection or machining methods, we offer complimentary consultations to help optimize your design and production. For any questions, please feel free to contact us.