Pinch Trim Cutting Edge Tolerances?

[aaronraad]

Anybody familiar with the CAD drawing tolerances (or symbol) for describing a cutting edge on punch and die tooling?

Just finishing off the dimensioning a pinch trim die, any assistance would be appreciated.

[aaronraad]

aaronraad,

Are you are asking how to dimension the punch diameter and the die bore diameter? For close tolerances, as in this case, I normally call out the max/min diameter of the punch and the min/max diameter of the hole.

PB

Diameters are okay, just the actual cutting edge/corner itself. Typically I'll spec out a 1mm or 0.2mm radius fillet on edges so the machinist isn't left wondering.

At the moment I've spec'd out a 0.12mm fillet on the inside cutting edge.

The best answer I've seen so far is the response to Question 3. in the link, which pretty much sums up why it's been hard to find: http://www.etinews.com/etimail/archi...ue04/#q3answer

[mactool]

I would look at this standard https://law.resource.org/pub/in/bis/...13715.1994.pdf. Another thing is how will you verify that the radius is there and is within the limits. I think it would be better to specifie that the edge is as result of lets say 30 min of wet tumbling with stainless steel pins.

[Valornor]

I've seen it done both ways, either calling out a small fillet (.005 TYP) or an addition of an note that says DO NOT BREAK EDGE.

In terms of what's proper, I think it's probably a best practice to call out a fillet on that edge. Personally I'll call out a fillet on the edge .005 MAX.