The concept of Lean Manufacturing is essentially to eliminate waste from the manufacturing process. Waste is defined as any activity that does not add value from the customer’s perspective.
Porosity in castings refers to any voids or holes in a metal component that are formed during the casting process, which may occur as the material changes state from a liquid to a solid. While porosity is a characteristic of cast aluminium as well as many other ferrous and non-ferrous materials, it is often classified as a defect and any replacement parts will need to be cast, machined, cleaned, and tested.
In terms of Lean Manufacturing, defects are one the “Seven Deadly Sins” and frequently lead to activity that adds cost not value. However, thanks to vacuum impregnation, expensive porous castings do not need to be scrapped, and some products can even be enhanced with the metal impregnation process.
It is far more cost effective to impregnate porous castings than to scrap them. Impregnation allows the manufacturer to save time, money, energy and ensure quality. By making vacuum impregnation part of the value stream, component quality is improved, and rejection rates are reduced. So, by reducing the number of potentially defective parts caused by porosity, Impregnation helps to reduce waste.
Due to the proven effectiveness and economies of impregnation, many engineers now specify its use for all types of metal parts that must contain liquids or gases under pressure. It is now common for impregnation processes to be incorporated directly into production schedules to ensure quality, rather than to be used only to recover porous components.
Sealing Pores with Vacuum Impregnation – The Process:
- The part is placed in a vacuum autoclave and vacuum is used to remove any trapped air in micro pores.
- A methacrylate resin is then introduced into the chamber, the vacuum is released and therefore the resin is forced into the micropores with positive air pressure.
- Resin is drained and washed off the surface of the item so that no excess resin is left on the surface.
- The item is placed in a water bath at a temperature around 95 degrees C and the thermal reaction ensures that the resin cures and seals the micro porosity.
- This is considered as a one-time, permanent surface treatment.
If you have 1 or 1,000 pieces, new or used, large or small, for recovery or sub surface quality enhancement, ISL can help. Our purpose-built facility allows us to turn ordinary castings into high-pressure, sub-surface sealed, fit for purpose parts, for use in any number of applications.
We provide vacuum impregnation of castings to a vast array of industries including aerospace, automotive, oil and gas, and marine.
Do you suffer from leaking or porous castings? Do you want to recover your castings and seal them for life? … Call the casting impregnation experts now.