Micro granules from Vestakeep 5000 HCM shown in the middle as compared to granules or powders (source: Evonik)
The company Evonik has developed Vestakeep 5000 HCM, which is a new PEEK (Polyetheretherketone) micro granules that increases the production efficiency of customized PEEK seals.
Hot compression molding as prefered process for customized products
Oil and gas seals made of PEEK in standard sizes and lengths are normally produced in three well established processes namely, injection molding, extrusion, and hot compression molding (HCM). If a customized product is needed then the HCM method is often selected because the associated costs for adapting the downstream manufacturing process are lower as compared to the injection molding or extrusion methods.
Minimization/elimination of air being trapped in
Being in the form of micro granules, Vestakeep 5000 HCM has been found to minimize or even eliminate air being trapped in the hot compression mold. On the other hand, traditional PEEK powders that are commonly applied in HCM are known to trap air easily in the mold that could leads to oxidation during processing. This would result in black spots appearing on the finished component. Presence of black spots can lead to additional reworking or even total yield loss for severe cases. In addition, the bulk density of Vestakeep 5000 HCM micro granules have been measured to be significantly higher than that of standard PEEK powder, resulting in better mechanical properties such as the elongation at break values.
Micro granules open up new possibilities
Another advantage associated with the design of the micro granule is the elimination of the additional step of grinding granules into powder. This immediately opens up new possibilities for micro granule PEEK compounds to be developed with glass fiber reinforced or even with fluoropolymer additives for the hot compression molding. This has not been possible with the PEEK powder due to the grinding step that will destroy the beneficiary effects of the reinforcement or the additives.