Machined Finished Plastic Parts

In compression molding, the PTFE suspension resin is uniformly added to the compression mold cavity, pressure is applied to form a preform, and after demolding, it is placed in the sintering furnace, and then sintered at a controlled temperature in a preset thermal cycle,and acquire PTFE molded products after cold cut. Compression molding is used to produce rods, tubes sheets,blocks and parisons.

PTFE and filled PTFE molded billets are skived into tapes of different thicknesses, ranging from 0.025mm (.001″) up to 6mm (.250″). The PTFE billet is skived by the mean of a sharp steel blade used at a low angle to the surface. The sharpness of the blade is vital in order to obtain high quality films and tapes without “lines” along the material. Ready ex stock tapes are available for the most common sizes and thicknesses. Special sizes, thicknesses and special compounds are available on request.

Due to the symmetry of the PTFE molecular chain structure, it is electrically neutral, and the molecules are non-polar, becoming a material with extremely low surface tension, so any glue will not affect the PTFE surface. Therefore, only through chemical treatment. The chemical treatment method is mainly to etch through sodium naphthalene treatment solution. Etching is a special chemical process that allows PTFE tapes, sheets or finished parts to be bonded on different substrates and materials. The bondable side (the etched surface) can be easily distinguished by the typical dark brown color after etching. High temperature, high humidity and most of all UV light have a detrimental effect on the etched surface. If not properly stored etched PTFE may lose its bondable properties even within hours. If properly stored the etching properties can last for weeks or months. In fact CYLEX Seal pack and ships all etched material in black plastic bags and can advise customers on storage conditions and shelf life.

Extrusion is a continuous process used for the production of semi-finished PTFE rods and tubes. A pre-sintered or free-flow PTFE resin is set into a die where it is pressed and sintered at the same time in a vertical extruder. Finally, the semi-finished is cooled at a rate that will lead to the desired crystallinity content. Afterwards the semi-finished can be stress relived with a specific annealing process in order to guarantee better dimensional stability during and after machining. Extruded rods and tubes can be also precision ground to strict tolerances for more efficient machining with automatic and sliding headstock lathes.

Isostatic forming (also called Hydroforming) uses high-pressure fluid to uniformly and constantly apply pressure to each part of an elastic mold that can be freely contracted or expanded to change shape during the entire cycle time, and uniformly applies pressure along the shape of the mold, forcing The elastic mold expands or shrinks, and the resin placed between the elastic mold and the metal mold wall is uniformly compressed and compressed into a preform of the desired shape. It is suitable for processing a small number of large components and complex-shaped lining structural parts, such as hemispherical shells, storage tanks, large blanks, tower columns, tees, elbows and reducers.

Let the free-flowing PTFE suspension resin automatically add to the hot mold cavity Compression molding is suitable for processing products with large batches, simple shapes, and small sizes, such as small seal rings, valve seats, etc. Automatic compression molding requires higher pressure than general compression molding, because its compression time is much shorter.