2078 Broken Edge meaning

[joecool1964]

Question regarding ISO 2768-1

I have a part drawing with ISO 2768-1 specification listed on the drawing.

Specification does not specifically state what is meant by "broke edge"
Attachment shows the natural edge condition that occurs during the stamping process.
The break band on the attached file is what metal stampers would call "BREAK OUT"

Is this area the definition of "broken edge"

If not could you state which area on the attachment is considered "broke edge"

Or is this "broken edge" only applicable to machine practices.

 

[juergenwt]

No! It has nothing to do with the area known as "DIE BREAK" or "Break Band".
ISO 2768-1 broken edge tol. deals with the condition or size of the edge. It is the size of a radius or a chamfer/bevel.
It is listed as f=fine, m=medium, c=coarse and v=very coarse.
The limits are given in relation to the nominal size.
Nominal size 0.5-3
f and m +-0.2
c and v +-0.4

Nominal size over 3 to 6
f and m +-0.5
c and v +-1

Nominal size over 6
f and m +-1
c and v +-2

In your case the size of the "Rollover" or "Draw-in Band".

Note: For nominal sizes below 0.5 the tol. must be listed with the nominal size.
Juergen