Inner and Outer Mold Line Definition in Sheet Metal Operation

IML defines the intersection of a plane that runs along the inner surfaces of the part. It is located inside the radius part.

OML is outside, but defines the intersection of the plane of the outer surfaces. It is in space, off the part.

You could use whichever surface is expected to fit to the surfaces of other parts. Alternatively, search on "K-factor bending".

i am agree with Lyn.IML the inside dimensions of sheet metal part and OML is the outer (like a square or U shape to be inserted in a given dimension .

Lyn ...Thanks..

But why we need to have IML/OML..is it related or gives any input for Form Block Manufacturing or Sheet metal forming??

As per Lyn's explanation.

IML and OML are important beacause they establish the location of your form block surfaces.

If the bend radius is large enough, the IML will also lie outside the curve.

Correct. My mistake.

As per Tornado's rebuttal!

Thank you Guys