Calculate hole distance
During bending, the material is permanently deformed. The inner side of the radius compressed while the outer side is stretched. These deformations can also occur with holes if they are in the zone of plastic deformation. To prevent this, it is very important to keep a minimum distance between the bend and the hole.
Distance of the edge of a hole to the bending line
Why do holes deform?
When bending metal plates, the shape of the material is permanently changed. Plastic deformations occur not only directly at the edge line but also in the surrounding area. In the inner radius, the material is compressed, while it is stretched in the outer radius.
These compressive and tensile forces can also affect holes that may be present in this area. The closer the hole is to the edge line, the more it deforms.
The material thickness and the opening of the die also have a direct influence on the size of the deformation area. The thicker the material, the wider the die opening and the resulting deformation area.
Why is it important that holes do not deform?
The deformation of holes can be an undesirable effect! Holes are carefully placed in the right places and in the required diameters. If the necessary minimum distances are not kept, the positions of the holes can shift so that the workpieces no longer fulfil the required tolerances.
This is particularly important for threads and fits. The slightest deviation in a hole can cause that the screws provided for it no longer fit. This also applies to fittings that must be within high tolerances.
This effect is strongest in the plastic deformation zone, but can also occur outside this zone.
How can these deformations be prevented?
The deformation of holes can be reliably avoided by constructors if holes are positioned in a safe distance from the deformation area. The holes must also be completely outside that deformation zone. Only in this way can the designer be sure that the holes remain intact.