PEEK plastic (Polyether ether ketone) The high-performance thermoplastic perfect for extreme conditions

What is PEEK plastic?

Polyetheretherketone (PEEK) is a semi-crystalline thermoplastic polymer from the PAEK family (Polyaryletherketones). Its extremely stable cyclic molecular structure gives it exceptional properties. It belongs to the very exclusive category of "high-performance thermoplastics". Due to its high production cost and processing complexity, it is a specialty material, reserved for critical applications where part failure is not an option.

The main properties and advantages of PEEK

PEEK is often the only possible choice when specifications combine severe thermal, mechanical and chemical constraints:

• Spectacular thermal resistance: this is its number one characteristic. PEEK retains its excellent mechanical properties at continuous operating temperatures up to 250 °C to 260 °C, and can withstand peaks beyond 300 °C.
• Chemical and hydrolytic inertness: it resists almost all organic solvents, oils, bases and acids, even at high temperatures. Furthermore, it offers excellent hydrolysis resistance (it can operate in pressurised steam without degrading).
• Superior mechanical properties: it combines very high tensile strength, excellent rigidity and exceptional fatigue and creep resistance (deformation under load).
• Fire behaviour: PEEK is intrinsically flame-retardant (certified UL94 V-0) without any additives and releases very little toxic smoke when exposed to flames.
• Biocompatibility: it is widely used in the medical field as it is non-toxic and withstands thousands of sterilisation cycles (autoclave, gamma rays, ethylene oxide).

The limitations of PEEK: which applications should it be avoided for?

Specifying PEEK requires rigorous analysis. Our design office will alert you to the following points to avoid over-engineering your project:

• Material cost: PEEK is one of the most expensive thermoplastics on the market. It should only be specified if its extreme performance is absolutely required. If your constraint is purely chemical at ambient temperature, we will direct you towards PTFE or HDPE to optimise your budget.
• Sensitivity to certain acids: although highly resistant, PEEK is attacked by concentrated sulphuric acid, concentrated nitric acid and certain halogens (such as pure chlorine or bromine).
• Demanding machining: its very high hardness and internal stresses require strict machining and annealing processes to avoid part distortion.

How does Plastisart process PEEK?

Due to its extremely high melting point (approximately 343 °C), PEEK cannot be thermoformed with standard equipment. At Plastisart, we process it by leveraging our precision engineering expertise:

• 3 and 5-axis CNC machining: this is the essential process for custom PEEK parts. We use very sharp carbide or diamond tools and meticulously manage spindle speeds to achieve perfect surface finishes and aerospace or medical tolerances.
• Heat treatment (annealing): during complex PEEK machining, the material can release internal stresses. Our workshops master annealing cycles (stepped oven heating) before or during machining to guarantee absolute dimensional stability of the finished part.
• Engraving and traceability: PEEK responds very well to laser marking. For the medical or defence sector, we can engrave unalterable Datamatrix codes or batch numbers directly into the material.

Industry sectors and typical industrial applications

PEEK is the ideal substitute for metals (steel, titanium, bronze) when a structure needs to be lightened while maintaining extreme reliability:

• Cabin components, fasteners, cable supports and engine parts in aerospace (drastic weight reduction compared to aluminium)
• Surgical instruments, dialysis components, sterilisation trays and implantable medical device parts (radiotransparent)
• Sealing rings, valve seats and downhole connectors subject to high pressure and high temperature (HPHT)
• Wafer carriers, thermal and electrical insulators for semiconductors

Why choose Plastisart for your PEEK parts?

Machining PEEK is a significant investment for an industrial. The margin for error is zero, as the slightest material scrap is very costly. By entrusting your project to Plastisart, you rely on a design office that verifies the accuracy of your drawings and on CNC operators experienced in managing high-performance polymers. We master the heating cycles, specific tooling and strict quality control required by critical parts.

FAQ about PEEK plastic