The relationship between the width of the lower die slot of the CNC press brake mold and the plate thickness is a question that many sheet metal processing manufacturers often inquire about.
The commonly accepted calculation formula in the market is:
Slot width (V) = Plate thickness * 8.
This is a widely used calculation formula in the market, but it also hides a drawback. Is this formula still applicable for workpieces that require precision? The answer is not entirely. This formula is only suitable for precision bending and may not be suitable for air bending and close bending. Additionally, the ratio of the lower die slot width to plate thickness may vary for different materials.
Based on data summarized according to market requirements, for sheet thickness t: for sheets ranging from 0 to 3mm, the lower die slot width of the press brake is V = Plate thickness t * 6, which can be narrowed down to 4 times the plate thickness for precision bending. For sheets ranging from 3 to 10mm, the lower die slot width is V = Plate thickness t * 8; for sheets above 10mm, the lower die slot width is V = Plate thickness * 12.
The above are common calculation methods in the market. Based on the experience of CNC press brake mold manufacturers and sheet metal processing experience, this formula is generally applicable for precision bending. For air bending and close bending, the multiplier relationship between the lower die slot width and plate thickness can be appropriately reduced.
If the material being processed is aluminum, the lower die slot width of the CNC press brake machine is V = Plate thickness t * 6, meeting the processing requirements. This also means that when processing aluminum, the material and hardness of the lower die of the press brake machine need to be higher than those of ordinary molds. The slot corner radius should be above 1.5mm to minimize damage to the workpiece during bending and keep the impressions shallow.
For air bending, the lower die slot width of the press brake mold can be reduced accordingly because this bending method does not require the upper and lower dies to completely form the shape. Reducing the slot width can also make the angles of the processed products more aesthetically pleasing. The width of the bending slot also determines the size of the radius at the bending angle of the workpiece.
If you want the processed product to have no radius at the bending angle, it is best to groove at the bending point before processing. This way, the sheet metal part produced will have a very standard bending angle without the influence of a radius, making it more aesthetically pleasing.
Therefore, the width of the lower die slot of the CNC press brake machine should be designed and produced reasonably based on the product's precision, material, and bending angle, rather than solely calculated based on the plate thickness. This approach is not scientific and does not align with common sense. By selecting the most suitable width of the lower die slot based on product requirements, the product qualification rate will be higher.
