Machining PE-UHMW EL black

PE-UHMW (ultra-high molecular weight polyethylene, also known as PE 1000) belongs to the polyolefin family and is characterised by an exceptionally low coefficient of friction, high wear resistance and very good impact strength. In the conductive EL version, the material is made electrically conductive by adding special conductivity carbons: it rapidly discharges electrostatic charges and thereby protects against sparking in potentially explosive atmospheres. Liedtke stocks this type in black with FDA suitability for food contact.

Like all PE-UHMW types, the conductive version owes its high toughness, abrasion resistance and permanent self-lubrication to the exceptionally long molecular chains of the base polymer, without the need for additional lubricants.

The incorporated conductivity carbons reduce the surface and bulk resistance to ≤ 10⁶ Ω and Ω · cm respectively. This value is markedly lower than antistatic/dissipative (ELS) types and makes the material the primary conductive type (EL) for ATEX explosion protection, for example when lining silos, chutes and tanks.

Advantages:

• Electrically conductive, surface resistance ≤ 10⁶ Ω – suitable for primary explosion protection
• High impact strength, even at low temperatures
• Good sliding properties, permanent self-lubrication
• Very low water absorption
• FDA-compliant for food contact (EL + FDA black type)

Limitations:

• Lower stiffness and dimensional stability than engineering plastics such as PA or POM
• More demanding to machine than many other thermoplastics – sharp tools required
• No transparency in the black version
• Conductivity depends on dry, unaltered material and may be reduced by surface processing

PE-UHMW EL can be milled, turned, drilled and sawn like other PE-UHMW types, using sharp tools suited to tough plastics; low cutting speeds and good chip removal improve surface finish. Before machining, the semi-finished product should be at room temperature and/or stored for at least 24 hours under normal ambient conditions.

PE-UHMW EL is used specifically where electrostatic charges need to be discharged quickly and reliably, for example when lining silos and chutes in the bulk materials industry, in components for the electrical industry, and on slide rails in mechanical engineering. The EL + FDA black type documented here is also suitable for food contact under 21 CFR § 177.1520.

Yes, the EL + FDA black type documented here complies with FDA 21 CFR § 177.1520 for food contact – see the separate FDA compliance declaration for download.