A Guide to PP (Polypropylene) CNC Machining

Key Takeaways

• PP is a lightweight, low-cost plastic with good wear resistance, impact resistance, and chemical resistance for a wide range of applications.

• Its excellent machinability and electrical insulation make it a versatile choice for general-purpose components.

• PP has poor UV resistance, is prone to burr formation during machining, and should not be used near open flames.

Overview

PP (polypropylene) is one of the lightest plastics available, with a specific gravity of just 0.9. It is produced in enormous volumes worldwide, which keeps costs low and makes it easy to source. Combined with straightforward machinability, this makes PP a go-to material across a wide range of industries.

It has a continuous use temperature of 100°C—on the higher end for general-purpose plastics—and offers solid impact resistance, good wear resistance, and a surface that holds up well against scratching.

PP is also largely unaffected by chemicals, with good resistance to acids, alkalis, and organic solvents at room temperature.

• Lightweight, even among plastics

• Low cost

• Good wear and impact resistance

• Excellent chemical resistance

• Electrical insulation

Material Selection Notes

PP has poor weather resistance. UV exposure will cause discoloration and degradation over time and can lead to a meaningful loss of strength. For that reason, outdoor or UV-exposed applications are not recommended.

PP also ranks among the more burr-prone materials in machining. For features where burrs are hard to remove and their presence matters, such as through-holes for fluid or gas flow, or small-diameter threaded holes, a cleaner-cutting material like POM is a better choice.

Finally, PP is flammable, so caution is warranted in any application near open flame or high heat sources.

PP CNC Machining at Yumoto Electric

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

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.