Vacuum impregnation is commonly used as a preventative measure to keep castings pressure tight. But when use on powdered metal parts, vacuum impregnation is used as a value added process. In this blog, we will answer the common questions we receive about impregnating powdered metal parts and explain why it is a value added process.
"Why is vacuum impregnation performed on powdered metal parts?"
The full range of design and applications for powdered metal components can be limited by the particulate nature of powdered metal. This structure causes problems during machining and surface finishing and may lead to sub-surface corrosion and oxidation. In addition, inherent structural porosity prevents the use of powdered metal parts in pressure applications.
Vacuum impregnation eliminates these problems by filling the openings and voids between the powdered metal particles, providing greater flexibility and new opportunities for the design and manufacture of powdered metal parts. This cost-saving technology is enabling design engineers and production managers to enlarge the range of applications for powdered metal components.
"Machining my powdered metal parts wears out my tooling and the machined finish is unsatisfactory. Greater machining efficiency would save me a bundle in tooling and production costs."
Powdered metal parts are generally made to "finished size and shape". Secondary machine operations, such as drilling, tapping or cutting are only marginally successful because voids between the particles cause tool chatter, reducing tool life and finish quality. Vacuum impregnation serves as a combination lubricant, stabilizer and support for individual powdered metal granules. After impregnation, machining is far more efficient, tool chatter is eliminated and the machined finish is greatly improved. Godfrey & Wing's impregnation technology greatly extends tool life (over 100 times) and allows design of powdered metal parts for use in areas where secondary machining is necessary.
"My application calls for pressure retention. How can I get leak-proof powdered metal parts that meet my specifications?"
Part leakage under pressure is caused by porosity, interconnected openings between the individual powered metal particles, stretching from wall to wall of the components. Vacuum impregnation permanently seals the porous openings. Your parts are virtually leak-proof and are capable of withstanding high pressures after vacuum impregnation.
"Finish operations are tough on my powdered metal parts. The plating is uneven and I keep getting bleed out that damages the surface finish."
These plating problems are caused by the voids between the metal granules of the part that allow plating solutions to permeate the component causing uneven and poor plating. Bleed out damage is caused by solutions that leech out of these voids in the part after plating. Godfrey & Wing's sealants fill the voids between the particles providing a barrier base for plating and eliminate subsequent bleed out, improving the quality and finish of your plated powdered metal parts.
Vacuum impregnation adds value to powdered metal components by enabling new opportunities for producing parts that require pressure retention, secondary machining and improved surface finishing.
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