Machining PEEK Plastic

Polyether ether ketone (PEEK) is a colorless organic thermoplastic polymer, and it is used in a variety of industries. Three key characteristics of PEEK materials are their strength, wear resistance and biocompatibility. They are softer than most metals but stiffer than most plastics. Some of PEEK’s other unique characteristics are:

  1. Low coefficient of friction
  2. Wear resistance
  3. Mechanical and chemical resistance
  4. Low moisture absorption
  5. Abrasion resistance
  6. Machinability

PEEK is excellent for applications that require strength and stability under the consistent use of high temperatures (500°F/260°C). You often find PEEK plastic in piston parts, pumps, electrical cable insulation and bearings. There is a rise in the use of PEEK for medical implant device components such as dental healing cups, spiked washers and spinal implants. It is also gaining popularity in the aerospace, automotive and chemical process industries.

Grades of PEEK

PEEK material is available in two basic grades: industrial-grade PEEK and medical-grade PEEK.

Industrial-grade PEEK keeps its mechanical properties at high temperatures. It is a flame-retardant material with abrasion resistance, high impact strength and a low coefficient of friction. The industrial-grade version is often used in the aerospace, automotive, chemical, electronics, petroleum, and food and beverage industries.

Medical-grade PEEK has the same properties as industrial-grade PEEK. On top of all those, it possesses biocompatibility and high chemical resistance. It also has compatibility with different sterilization methods and is naturally radio translucent.

Tips: Machining PEEK Plastic

These are some basic tips you should be aware of when machining PEEK polymer.

  1. PEEK materials usually come in the form of rods.
  2. Before machining, stress-relieve PEEK through an annealing process to decrease the possibility of surface cracks and internal stresses.
  3. As PEEK is softer than most metals and stiffer than most plastics, fixturing is crucial.
  4. While PEEK can endure high temperatures and has a high melting point, it still requires coolant. Avoid overheating and surface melting by providing sufficient coolant such as pure water.
  5. PEEK grades are abrasive on tooling, especially if they are reinforced with carbon fiber and glass.