PEEK CNC machining service Custom PEEK parts

The recent popularity of PEEK (polyether ether ketone) in complex industries such as aerospace and defense, medical and life sciences is well-documented, and for good reason: this lightweight thermoplastic has properties that make it suitable for a wide range of specialized applications. This versatility allows PEEK to be used equally well for implants and customized medical devices or machined light aircraft components.

What is less well known, however, is the process of machining this plastic material. With over 35 years of experience processing this thermoplastic material, we at AIP have written a brief introduction to PEEK processing. We hope this gives you an insight into our polymer machining process and how it differs from metal machining or injection molding.

Plastic CNC Machining

Before discussing PEEK machining, it is important to understand plastics machining accurately.CNC (Computer Numerical Control) machining is a process in manufacturing that involves the use of computer-controlled machine tools. In the case of plastics machining, this involves the precise removal of layers from the plastic material. The Massachusetts Institute of Technology (MIT) introduced the technique of using drilling tools to sculpt plastics in the 1950s, and because the process is computer-controlled, it is possible to obtain products with extremely high tolerances.

Due to the wide variety of polymers and composites, it is important to have strong technical expertise with polymer materials when machining plastic parts; for example, some plastics are fragile, while others are cut similarly to metals. The challenge with plastics is their wide range of mechanical properties and different behavior when machining. Therefore, it is important to understand the polymer structure of PEEK when processing it.

Industrial Grade PEEK is a strong, flame-retardant, wear-resistant thermoplastic with high impact strength and a low coefficient of friction. It is known for maintaining its mechanical properties, even at high temperatures. As its name suggests, this grade is most commonly used in the aerospace, automotive, chemical, electronics, petroleum, and food and beverage industries.

Medical grade PEEK adds biocompatibility, high chemical resistance, and sterilization compatibility in accordance with ISO 10993. In addition, this thermoplastic is radiolucent, meaning it is not visible under X-ray, MRI or CT. Medical grade PEEK includes polymers suitable for implants, such as PEEK Optima and Zeniva PEEK, which can remain in contact with blood or tissue indefinitely while mimicking the hardness of bone. Other variants of medical grade PEEK can be used to customize medical components and applications such as joint and spinal instrumentation.

Machined PEEK

Annealed PEEK Most stores receive PEEK rods in a variety of lengths, ranging from 6mm to 150mm in diameter. Stress relief prior to machining through the annealing process is critical as it reduces the likelihood of surface cracking and internal stress generation. Other benefits of annealing include improved crystallinity and limiting the opportunity for dimensional changes.