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1.6Ra surface finish on a Shot blasted component

2004

We have a certain Aluminium Die Cast component having 6 Valve seating ports. The customer wants to have a Surface finish of 1.6 µm Ra on the taper valve seating area ( in an as-cast condition ) as there is no further machining on that zone.

We are able to achieve a good Surface finish on the casting (as it is generated by core pins which are ground optically and coated for wear resistance ) but the surface finish is lost when we do Shot Blasting of the component. One probable solution could be to mask the areas locally and do Shot blasting (which we are planning to attempt ).

Would appreciate if you could throw some light on finding a solution to the above problem.

T.S. Rajan
- Chennai, Tamil Nadu, India

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You have the right answer for your problem. Blasting will not produce an acceptable RMS.

AF Kenton
retired business owner - Hatboro, Pennsylvania
2004

Try using rubber corks to protect holes you don't want blasted. Hardware stores carry them or contact a laboratory supply company for a very large selection of sizes.

Herb Snyder
sandblasting professional - Shenenandoah Junction, West Virginia, USA
2005

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alumunium items required for shot blast in the rail and aerospace industry use shot system that has the shot product encapsulated in sponge to reduce effect of blasting,
patented method, aerotech in halesowen west midlands england used to offer this service,

ken murray
- wolverhampton uk
January 29, 2009