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New technologies include a large-envelope vacuum system for large-volume, light- to medium-weight part impregnation.
The steady rise in the volume of aluminum castings being produced, in particular automotive engine and powertrain parts, has spurred a significant expansion in the variety of products and systems for sealing those parts, to address inherent porosity. While aluminum alloys offer automotive designers an option for producing lightweight parts in high volumes, aluminum castings often present porosity defects, small surface-level holes or cracks that can be permeated by fluids or gases. Porosities appear as castings change from a liquid to a solid state. They present a functional problem for engine blocks, cylinder heads, and compressors, and if not properly sealed they can lead to corrosion, pressure loss, fluid loss or even failures while in service.
Sealing the castings ensures they will not leak gas or fluid, and that they will provide appropriate resistance to chemicals, aggressive fluids and high operating temperatures in service. The process for doing sealing them is impregnation: castings are coated with a resin formulation, and frequently that resin is sealed to...