Need source for "better" 3/16" 6061 plate

[Finegrain]

Hello,

I make a family of parts from 3/16" 6061 plate. Parts finish to nominal thickness, ~8" wide, between 14 and 20" long. They get a bunch of pockets and holes put in. Flatness +/-.01", thickness +/-.005". I've been trying to use commodity 3/16" 6061 plate, but much of the time, what I get is not flat enough, and runs .007"-.01" thicker than nominal. These pieces are (IME anyway) too flimsy to reliably mill flat and on-size.

It seems K100-S and MIC-6 start at 1/4", so those are out.

Precision ground would be well within tolerance, but far higher cost, likely higher than my customer would allow.

Is there a "better" 6061 (or similar) plate product out there?

Thanks, and regards.

Mike

 

[MaxPrairie]

A vacuum plate would give you a more reliable thickness but wouldn't get you the flatness tolerance. If this is bolting to a mating part and assuming the mating part is more rigid, it is going to be as flat as what it is bolting to. Double sided tape can allow some "float" to the plate while skimming and give a flatter result. Others have used heat release epoxy for easier removal.

I think Kaiser select plate has been the flattest cast plate I have used, but again starts at 1/4". If you were to start with a flat 1/4" plate and vacuum it and skim 1/16 off assuming zero stress you would be pretty flat and parallel.

 

[AARONT]

I've had similar projects come up in the past. The best route I found was to order material to my spec from DIX Metals. It's still spendy, but it was the best I was able to find(and the customer paid).