Production process for our fluoropolymer tubings

In the classic extrusion of fluoropolymer tubing, the plastic granulate is continuously conveyed in an externally heated barrel by the rotary motion of a screw. The material is evenly compacted, homogeneously melted and processed into a moldable melt.

At the end of the extruder there is a melt filter which - similar to a sieve - removes remaining particles and volatile components from the melt. An integrated melt pump compensates for pressure fluctuations and ensures a constant material flow, guaranteeing tight dimensional tolerances and a uniform wall thickness of the extruded tubing.

The prepared melt is then fed to the die head, where the shaping nozzles and mandrels produce the desired tubing geometry. In the downstream vacuum calibration bath, the still soft tunbing is fixed under controlled conditions and stabilized to size.

After calibration, it is cooled down in the water tank. Inline measuring systems - such as laser or ultrasonic measurements - continuously monitor the diameter and wall thickness to ensure consistently high product quality. The tubing is then guided in a defined manner over a take-off conveyor, cut to length or wound up for further transportation.

This process forms the basis for the precise and reproducible production of high-quality fluoropolymer tubings - from standard designs to customer-specific special solutions.

Co-extrusion is basically based on the same process as classic extrusion, but adds the option of processing several materials at the same time. Two or more melt streams are precisely combined in the die head, resulting in a tube with a defined multilayer structure or integrated functional strips.

This process allows various properties to be specifically combined in one product - for example chemical resistance, flexibility, barrier effect or conductivity. The functional strips can either be placed on top of the tubing wall or completely embedded in it, depending on the desired application.

Different layers can also be created within a tubing to take advantage of specific material benefits on both the inside and outside. This results in customized tubing solutions with clearly defined functional zones - for example for marking, electrical discharge, X-ray visibility or media-side separation.

Co-extrusion therefore offers a high degree of design freedom and enables the production of complex tubing systems with precisely coordinated material properties and outstanding dimensional accuracy.

Paste extrusion is a special process for manufacturing tubings and semi-finished products from polytetrafluoroethylene (PTFE) that differs significantly from classic melt extrusion. As PTFE cannot be melted, it is shaped using paste extrusion on the basis of a finely divided PTFE powder that is mixed with a temporary lubricant.

The extrusion mixture produced in this way is placed in a cylinder and pressed through a nozzle under high pressure. This produces a so-called pre-product - a dimensionally stable, but not yet sintered tubing blank. After the extrusion process, the lubricant is removed by controlled drying. The material is then sintered at defined temperatures, resulting in the typical, dense PTFE structure.

This process enables the production of thin-walled, high-purity and at the same time mechanically resilient tubings with excellent sliding and insulating properties. PTFE tubings manufactured using the paste extrusion process are characterized by their exceptional chemical resistance, high temperature resistance and low gas permeability.

APT uses paste extrusion in particular for applications that require the highest purity and precision - for example in the analytical, chemical and food industries. Thanks to many years of experience and in-house tool development, tubing geometries and dimensions can be adapted precisely to customer-specific requirements.