Machining 32 Finish in ANSI 380 AL Die Casting

[winchengr]

Need 16 to 32 microinch surface finish in 3.00 inch bore of alum die casting. Piston O-ring must seal 2500 psi on this surface.

First attempt to machine the required finish resulted in rougher finish (45-70). Part is machined on a Mazak machine. Hand polished bore and got required finish, but this would add too much time in production quantities.

Any recommendations on how to machine the bore to get 16-32 finish without subsequent operation would be appreciated.

 

[MintJulep]

What is the diameter of the rough hole in the casting? How long?

 

[unclesyd]

I would give these people a call. I think you will need a better finish than a 32. These tools will give you a better finish and a truer bore.

http://www.engis.com/techsupport/bfcasestudy6.html

 

[winchengr]

MintJulep and unclesyd,

Thanks for the replies.

MintJulep: Here is info on bores. There are two stepped bores.

1st bore
Cast bore 3.325" dia
depth of cast bore 1.514"
Machine finished bore 3.375" dia

2nd bore
Cast Bore 3.450" dia
depth of cast bore 1.056"
Machine finished bore 3.500" dia

 

[swall]

I would expect that you will uncover porosity when you machine the bores, irregardless what what RMS you finish to. You may need to rough bore ,impregnate and finish bore.