1, Aesthetic aspects of designing holes in sheet metal parts
In our work we often see sheet metal part structures, assemblies where fastenings are often made with fasteners through holes. In such cases, besides the technical conditions, these solutions must also satisfy the aesthetic conditions, especially when edge bending is part of the sheet metal fabrication process.
In our work we often see sheet metal part structures, assemblies where fastenings are often made with fasteners through holes. In such cases, besides the technical conditions, these solutions must also satisfy the aesthetic conditions, especially when edge bending is part of the sheet metal fabrication process.
For this reason, several aspects need to be considered already in the planning process. First of all, it is advisable to place the hole as much as possible towards the edge of the part, the central locations and the most prominent positions should be avoided. In many cases, the designer often chooses positions where implementation is difficult. Obviously, the proximity of the bending edges is in many cases a much firmer, stronger surface for the fastening, but we may encounter some problems. Holes that are too close to the bends may be distorted and they pull the nearby flat surfaces during bending, which will result in aesthetic damage.
A possible solution for the constructor if the holes can be moved before the production.
A possible solution for the constructor if the holes can be moved before the production.
2, Possible modifications during the manufacturing preparation phase- definition of minimum folding edges
During metal bending, the raw material is deformed along the bending edge such that the inner side is compacted and the outer one is stretched. Holes close to the bending edge may deform in oval shape due to changes in the internal structure of the raw material.
Determining the minimum folding edges helps determine the hole position. If the hole is not placed in this minimum folding size, there is a good chance that it will not be distorted. The following table summarizes these minimum dimensions: Bending Tables
Determining the minimum folding edges helps determine the hole position. If the hole is not placed in this minimum folding size, there is a good chance that it will not be distorted. The following table summarizes these minimum dimensions: Bending Tables
3, Cutting the bending edge or making a knockout in the position of the hole
Cutting the area between the bending edge and the hole or making a knockout here prevents deformation of the side of the hole near the bending edge. With this solution, the position and shape of the hole correspond to the desired requirements. When making a knockout we cut the deformable base material across the entire width of the bending edge. In the course of cutting, the raw material is cut in the center line of the bending edge. This ensures that the material is not distorted on this part of the the bending edge during bending.
If hole distortion is not allowed, cutting the bending edge or making a knockout in the hole position can eliminate the problem.
Cutting the area between the bending edge and the hole or making a knockout here prevents deformation of the side of the hole near the bending edge. With this solution, the position and shape of the hole correspond to the desired requirements. When making a knockout we cut the deformable base material across the entire width of the bending edge. In the course of cutting, the raw material is cut in the center line of the bending edge. This ensures that the material is not distorted on this part of the the bending edge during bending.4, Making a knockout around the hole
Design programs allow you to pre-sketch the area around the hole as shown here. This solution speeds up design work and reduces the shape distortion of the holes.
before moving the holes.
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