Impregnation Process

What Is IMPREGNATION? Impregnation involves forcing a polymer based resin into the porosity of metal castings. The resin is then hardened, thus sealing the part from leaks, making an otherwise scrap part usable.

Impregnation is the fastest, most effective process for eliminating the inherent problems of porosity in cast and powdered metal. Properly processed castings are clean and have no change in appearance or dimensions. The phocal seal in impregnated castings is permanent.

What is the IMPREGNATION process?
First castings are placed in processing baskets, then baskets are placed in an impregnation vessel and the vessel closed and sealed. A vacuum is then drawn inside the vessel to evacuate the air and moisture out of the porosity in the casting. At this point the resin is transferred into the vessel until the castings are completely covered. Due to capillary attraction caused by the vacuum, the impregnation resin starts to wick its way into the microscopic porosity. The tank is then pressurized to 100 lbs psi. This pressure helps force the resin deeper into the porosity of the casting.

After the pressure cycle is complete, the resin is transferred from the vessel back into the storage tank. Once the castings are removed from vessel they are placed in a Centrifuge which spins the basket of castings to reclaim the excess resin. The castings are transferred to the rinse tank and rinsed in 100 degree F, clean water. The process will remove all resin from the exterior of the casting, leaving behind only that resin which was forced into the microscopic passages. The basket is transferred to a cure tank and submersed in 200 degree F water for 10 minutes. The Thermo cure resin material is polymerized (solidified) in the porosity from the heat, thus sealing all microscopic passages in the part.

After castings are cooled to the touch, they are ready for leak testing, machining, and/or final assembly.