1. Requirements for calculation of bending missing corners and bending hemming:
1. If the customer's drawing specifies which side to wrap, the side that wraps the missing corner shall be calculated according to the drawing requirements.
2. If the drawing does not specifically require the side to wrap the edge, the side that wraps the edge shall be determined by itself. However, if the assembly relationship is clear, the hemming surface is generally the visible surface and the hemmed surface is invisible.
3. If the drawing does not indicate the size of the missing corner, the calculation of the bending process gap of our factory is usually as follows:
① If the corner position needs full welding, the two sides will shrink (t+0.1), (the hemming height is greater than 100, and the drawing does not specify full welding, this process is not suitable);
2) For hemming without opening a process hole, one end of the hemming is shortened by 0.35t, (calculated to one decimal place), and the hemmed side is shrunk by (t+0.2t);
3) For hemming that requires a process hole, the size of one end of the hemming remains unchanged, and the hemmed side is shrunk by (t+0.2t). The specific calculation method depends on the customer's requirements for the product, the product's performance, material thickness, material, bending height, and whether it is welded, etc. Under the premise of meeting customer requirements and product performance, try not to weld at the corners, and try not to use full welding (you can spot weld inside and outside, fillet the corners to cover the welds, and eliminate the welds after spraying) to achieve the purpose of reducing workload and ensuring product quality. (The radius of the process hole is slightly smaller than the plate thickness)
2. Calculation of 90-degree "V"-shaped corner notch: The dimension from the end to the center of the first "V"-shaped cut is the side length minus 0.5K, the distance between the centers of the two "V"-shaped cuts is the side length minus K, and the center lines of the cuts are offset outward by 0.05 to 0.2 as the process gap (depending on the material thickness, the thicker the material thickness, the larger the gap)
3. Punching double bends, pressing dead edges and bending coefficients:
1) Usually a coefficient is reduced for right-angled edges; (between 85 and 99 degrees, it can be calculated as a right angle) 130 to 165 degrees minus 0.5t; 100 to 129 degrees minus 0.4k to 0.7K; (the smaller the angle, the larger the coefficient value) 60 to 84 degrees minus 1.43t; below 60 degrees, trial bending verification is required before batch production; (the coefficient value varies with material and thickness) The coefficient can be ignored for 165 to 179 degrees.
2) The calculation method for double-bend expansion is: total length of part L + 0.5t.
3) The calculation method for dead edge expansion is: total length of two sides minus 0.5t.
