Machining PE-HD

PE-HD belongs to the polyolefins – thermoplastics with a pure hydrocarbon chain. The high density (around 0.95 g/cm³, yet lighter than water) gives a denser molecular packing than the softer PE-LD and therefore more strength, stiffness and hardness. PE-HD is tough, impact-resistant and slides well, yet is comparatively soft (Shore D 62) and yielding. It absorbs virtually no moisture and is chemically resistant across a very wide range.

PE-HD machines easily and cleanly – turning, milling, drilling and sawing are effortless. Because of its softness and high thermal expansion, we use sharp tools and adapted cutting parameters, ensure good cooling and account for spring-back and dimensional changes at tighter tolerances. This is how we reliably produce tank, sliding and wear parts – from single pieces to series production; welded assemblies on request.

PE-HD is worthwhile whenever chemical resistance, toughness and low weight are required at low cost – for example:

• Tanks, linings and components in contact with aggressive media
• Sliding and wear parts such as guides, wear strips and chain guides
• Components for food processing (FDA-compliant, cutting boards)
• Impact-resistant applications down to about -50 °C
• Light, corrosion-free components in water and apparatus construction

PE-HD is one of the most economical engineering plastics and is priced considerably below POM, PET, PA and high-performance plastics. As a rough guide, semi-finished stock prices are in the range of about 3–8 €/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:

• Precision parts with tight tolerances – high thermal expansion, creep tendency and softness; use PET or POM instead
• High mechanical load or stiffness requirements – low modulus and low strength
• Continuous service above about 80 °C – then PA, PVDF or PEEK
• Components with fire-safety requirements – PE-HD only reaches UL 94 HB
• Bonding – PE-HD is difficult to glue without elaborate pretreatment (welding preferred)

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

Disadvantages:

Practical tip: PE-HD plays to its strengths wherever chemical resistance, toughness and low cost matter – for example in tanks, linings and sliding parts. Where high stiffness and dimensional stability are required, we recommend PET or POM; for higher temperatures PA, PVDF or PEEK. For permanent outdoor use, a black, UV-stabilised grade is preferable.

• Very broad chemical resistance
• High toughness and impact strength, even in the cold (down to -50 °C)
• Very low moisture absorption, good sliding properties
• Suitable for food contact, physiologically inert
• Light, easily weldable and very economical
• Soft and yielding – low strength and stiffness
• High thermal expansion and creep tendency – limited dimensional stability
• Continuous service limited to about 80 °C
• Only UL 94 HB, hard to glue without pretreatment, natural grade not UV-resistant