The material

Polytetrafluorethylen (PTFE)


better known as Teflon (Du Pont) or Hostaflon (Dyneon), is a material with almost unlimited fields of application.
Skived tapes are often used as
– seals
– slide plates and bearings
– non stick coatings

Polyethylen (UHMW-PE)


– bearings
– bushes
– slide plates
UMMW-PE is more ware resistant than PTFE


Processing


Processing of PTFE is more difficult than that of standard thermoplastics. At high temperatures (340-380°C) PTFE will merely become highly viscous. That means that injection-molding or regular extrusion is impossible. For this reason, semi-finished products are manufactured by means of compression-sintering or ram-extrusion.

PTFE powder is fed into a cylindrical tool and then condensed under high pressure. An important requirement of this process is that the air contained inside the tool can almost completely escape. The powder is then compressed on speed-, pressure- and time-controlled hydraulic presses. After this process, the pre-molded parts are sintered in electrically heated, circulating-air ovens according to specified programs. For optimum compound properties, compression and sintering parameters must be adapted to the respective PTFE compound.

Ram-extrusion is a compression process enabling the production of continuous profiles. The granulate is fed to a cylindrical extrusion pipe via a metering device, condensed by a hydraulically activated ram, and then conveyed through a field inside the pipe heated up to sintering temperature. In the sintering area, the individually metered batches "melt together" to a continuous profile.