Machining ECTFE

ECTFE belongs to the group of fluoropolymers and is an alternating copolymer of ethylene and chlorotrifluoroethylene. This structure gives it high chemical and thermal resistance combined with very high toughness and impact strength – even at low temperatures down to about -50 °C. Unlike more brittle-appearing fluoropolymers, ECTFE is remarkably ductile with around 250 % elongation at break. It can be machined and welded, absorbs virtually no moisture and is high-purity.

ECTFE machines well – turning, milling, drilling and sawing produce clean results. As ECTFE absorbs virtually no moisture, the components are dimensionally stable; we ensure sufficient cooling and adapted cutting parameters to avoid heat build-up. Because of its high toughness, we use sharp tools. This is how we reliably produce precision parts for chemical, semiconductor and cleanroom applications – from single pieces to series production.

ECTFE is worthwhile whenever the highest chemical resistance – including against strong alkalis – must be combined with toughness, purity and fire safety – for example:

• Linings and components for aggressive media, chlorine and oxidising agents
• Components for the semiconductor industry and cleanroom technology (high-purity, low outgassing)
• Components requiring fire safety and low smoke generation
• Applications with low-temperature impact and outdoor weathering loads
• Chemical plant engineering with media that attack PVDF (strong bases, amines)

ECTFE is a high-performance fluoropolymer and is priced considerably above PVDF and most engineering plastics. As a rough guide, semi-finished stock prices are in the range of about 40–90 €/kg. The component price is determined mainly by the semi-finished shape and dimension, material utilisation (offcut), machining effort and lot size. We are happy to quote binding prices on request based on your drawing.

Equally important are the limits of the material:

• High mechanical load or stiffness requirements – moderate modulus and yield stress; then PVDF, PEEK or filled materials
• Very tight budget – ECTFE is an expensive high-performance fluoropolymer
• Continuous service above about 150 °C – then PTFE/PFA or PEEK
• When PVDF is sufficient at lower cost (provided no strong alkalis are involved)

An honest assessment – and how the disadvantages can be mitigated in practice: Advantages:

Disadvantages:

Practical tip: ECTFE plays to its strengths wherever aggressive media – especially strong alkalis – meet toughness, purity and fire safety, for example in semiconductor manufacturing or chemical lining construction. Where the resistance of PVDF is sufficient and no strong bases are involved, PVDF is more economical; for higher temperatures, PTFE/PFA or PEEK are options.

• Outstanding chemical resistance – including against strong alkalis
• Very high toughness and low-temperature impact strength (down to -50 °C)
• Inherently flame-retardant (UL 94 V-0), low smoke generation
• High purity – ideal for semiconductor and cleanroom
• High continuous service temperature (up to 150 °C) and good weathering resistance
• Moderate strength and stiffness (tensile modulus around 1,500 MPa)
• High price – expensive high-performance fluoropolymer
• Continuous service limited to about 150 °C
• Combustion products contain hydrogen fluoride and hydrogen chloride – observe fire safety