In bending, the point of contact between the face of the die block applying force against the material being bent and the circumference of the bend form. In rotary-draw and compression bending, this would be the contact between the pressure die and the bend die. In press bending, this would be the contact between the wing die and the ram die. The ray passing through this point is known as the line of tangency, despite the fact that geometrically the tangent is actually perpendicular to that ray.
by builtbyRVWS | Jul 3, 2017