Machining PPE natural

PPE natural is an amorphous engineering thermoplastic based on modified polyphenylene ether (PPE blend). It is characterised by very low moisture absorption, high dimensional stability, very good electrical insulating properties and high resistance to hot water and steam – at low weight and with flame retardancy. PPE natural combines a yield stress of 65 MPa and a tensile modulus of 2,400 MPa with good toughness (elongation at break 30 %) and a continuous service temperature of around 105 °C; under low load the material remains dimensionally stable up to more than 140 °C. Moisture absorption of only 0.07 % (24 h) ensures constant dimensions and electrical values independent of ambient humidity; the density of 1.08 g/cm³ is among the lowest of all engineering plastics. PPE is hydrolysis resistant, resistant to many acids, alkalis and cleaning agents, and flame retardant without additives (UL 94 V-1). As an amorphous material, PPE is sensitive to stress cracking in contact with aromatic and chlorinated solvents, fuels and oils, and has only limited UV resistance. Wear resistance is lower than that of POM or PA; the product is not declared for food contact.

PPE natural can be machined well using all conventional cutting methods; sharp HSS or carbide tools and good cooling via chip removal avoid heat build-up and stress cracking. Cooling lubricants must be compatible with PPE – aromatic and chlorinated solvents must be avoided; if in doubt, machine dry or with compressed air. For tight tolerances and thick-walled parts, we recommend intermediate annealing to relieve machining stresses; thanks to the very low moisture absorption, no conditioning is required.

PPE natural is used wherever dimensionally stable, electrically insulating components are required in humid or hot environments – for example in the electrical industry, in medical technology, in the paper industry and in mechanical engineering.

• Insulating and housing parts for electrical engineering
• Components in contact with hot water and steam
• Dimensionally stable precision parts for medical technology and automation

PPE natural is calculated individually based on drawing or sample. The part price is determined mainly by the semi-finished form and dimensions, material utilisation and offcuts, machining effort and batch size. We are happy to provide binding prices on request.

The limits of the material are equally important:

• Sensitive to stress cracking with aromatic and chlorinated solvents, fuels and oils
• Limited UV resistance, lower wear resistance than POM/PA
• Not generally declared for food contact (see FDA declaration)

An honest assessment:

• Advantage: Very low moisture absorption, high dimensional stability
• Advantage: Very good electrical insulating properties
• Advantage: Hydrolysis and hot-water resistant, flame retardant (UL 94 V-1)
• Advantage: Low weight, good toughness
• Disadvantage: Sensitive to stress cracking with aromatic and chlorinated solvents, fuels and oils
• Disadvantage: Limited UV resistance, lower wear resistance than POM/PA
• Disadvantage: Not generally declared for food contact (see FDA declaration)