1. According to the shape of the workpiece, the discharge mode and the condition of the press, first determine the arrangement of the guide columns;
2. According to the variation of the blanking gap, the tolerance of each part is allocated. Generally, the manufacturing tolerance of the convex and concave die is one-half to one-third of the variation, and the bending deflection of the guiding column is one-fourth to one-fifth. The amount of change, the amount of change in the punching clearance of the guide post guide sleeve and the gap is one-half to one-third of the change;
3. Determine the size of the guide post according to the allowable bending deflection of the guide post and the lateral force during punching (mainly when punching the unsealed part);
4. Determine the maximum matching clearance of the guide bush guide bush according to the change amount of the punching clearance and the arrangement form of the guide bush guide sleeve according to the assigned matching clearance;
5. Determine the minimum fit clearance of the guide bush guide sleeve according to the maximum fit clearance of the guide bush guide bushing and the machining tolerance of the guide post bushing;
6. Determine the geometrical tolerance of the guide bush guide sleeve according to the minimum fit clearance of the guide bush guide sleeve.
The principle of selecting the matching precision of the guide pillar of the mold guide post is that the clearance of the guide sleeve of the general mold guide post should be smaller than the clearance of the convex and concave molds, and how to choose the fit of the guide sleeve of the mold guide pillar in several cases. Although these statements are correct, they are not accurate enough and are difficult to select in practical applications.
First of all, to ensure that the qualified parts are punched out and that the mold has a long life, the convex and concave mold gaps should be within the maximum and minimum reasonable clearance during the blanking process;
Secondly, in the blanking process, in addition to the influence of the guide bushing of the mold guide post and the clearance on the blanking gap, the lateral force during punching, the processing of the mold, the assembly precision and other factors also have an influence on the punching clearance. These factors are used to punch the gap. The effects should be combined to ensure that the mold gap is within a reasonable blanking clearance.https://www.xhychromerod.com/