Laser cut thermal pad tolerancing

[franhd]

Hi everyone,

I have designed thermal pad cutouts for their particular components. These will just be laser cut to shape from .006" stock rolls and then applied.

Because of having many variations, is there a blanket method to assign all cutouts the same profile tolerance without specifying datum on every part and call it a day?

I don't look forward to sitting there and slapping datums, basic dims, and profile callouts on all of them when these aren't critical.

Thanks!

 

[3DDave]

For flat parts all that one would need do is to establish the flat face as a datum feature and then indicate, in this case with a note, that the shape (and any holes) have a profile tolerance related to that face.

I am not sure how one gets around specifying the basic shape and the dimensions thereof, which are a key item in determining what the profile tolerance is controlling variation from. At the least the person(s) programming the laser cutter need to be informed.

 

[franhd]

Much appreciated, Dave.

I took a look at Y14.31 (undimemensioned drawings) and page 17 looks very similar to what I'd want to do.

Like you specified, flat face datum is called out with an all around profile assigned.

I understand in some respect it's good practice to call out basic dims as points to check variation, but now my question is, to what extent? Are overalls enough?

 

[3DDave]

In undimensioned drawings the drawing themselves, on stable base material, are the inspection gauges. The dimensions are used to check the accuracy of the stable base and have locator points that are used for that purpose.. I haven't used them except for decals and other artwork that would be exhaustive to dimension and to measure; these drawings are used as camera-ready work to generate the negatives for making the finished pieces.

I don't have a copy of the latest version of Y14.31. Never had need for it on non-artwork parts. For non-artwork parts we would reference the part files as the source of basic dimensions.