PTFE is more difficult to process than the usual thermoplastics. At high temperatures (340-380 °C), PTFE merely becomes highly viscous, so that injection molding or ordinary extrusion is not possible. Semi-finished products are therefore manufactured by press sintering or ram extrusion. Skiving blocks or skiving rounds for film production are mainly manufactured by press sintering. PTFE powder is placed in a cylindrical die and then compressed under high pressure. It is important that the air trapped in the tool can escape almost completely. The powder is pressed on hydraulic presses with speed, pressure and time control. After pressing, the preforms are sintered in electrically heated convection ovens according to specified programs. In this process, the pressing and sintering parameters must be matched to the respective PTFE compound in order to ensure optimum material properties.
Ramextrusion is a pressing process that enables the production of continuous profiles. The granules are fed into a cylindrical extrusion tube via a metering device. It is compacted by a hydraulically actuated ram and conveyed in the tube through a zone heated to sintering temperature. Here, the individual metering batches "melt" together to form a continuous profile.
 

For the skiving process, the skiving block is pressed onto a steel core (skiving mandrel), which is then clamped into the film skiving machine. A knife, which is fed depending on the film thickness and the speed of the block, can then be used to skive a continuous film. After the skiving process, this is wound onto a cardboard core using a winding device.