Method for determining the fitting clearance and shape tolerance of Cylindrical guide bush Manufacturers
Mold guide pin guide sleeve is a kind of mold accessory material commonly used in molds. There are many types of mold guide Cylindrical guide bush. How do we choose the Cylindrical guide bush that suits us when we need mold Cylindrical guide bush?
The method of determining the clearance and shape tolerance of the Cylindrical guide bush. The idea and method steps are as follows when designing the guide pin and guide sleeve:
1. According to the shape of the workpiece, the discharging method and the condition of the press, first determine the layout of the guide post;
2. According to the change of the blanking gap, the tolerance of each part is allocated. Generally, the manufacturing tolerance of the convex and concave molds is one-half to one-third of the change, and the bending deflection of the guide post is one-fourth to one-fifth. The amount of change of the guide post and guide sleeve matching clearance to the blanking clearance 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 Cylindrical guide bush and the size of the lateral force during punching (mainly when punching unclosed parts);
4. Determine the maximum fit gap of the guide post and guide sleeve according to the amount of change of the allocated fit gap to the blanking gap and the arrangement of the guide post and guide sleeve;
5. Determine the minimum fit clearance of the Cylindrical guide bush according to the maximum fit clearance of the guide pin and guide sleeve and the machining tolerance of the guide pin and guide sleeve;
6. Determine the geometric tolerance of the Cylindrical guide bush according to the minimum fit clearance of the guide post and guide sleeve.
The principle of choosing the matching accuracy of the mold guide pin and bushing is that the matching gap of the mold guide pin and bushing should be less than the gap between the convex and concave molds, and how to choose the matching of the mold guide pin and bushing under several conditions. Although these statements are correct, they are not accurate enough and difficult to choose in actual application.
First of all, it is necessary to ensure that qualified parts are punched out and the mold has a long life. The gap between the convex and concave molds should be within the maximum and minimum reasonable gaps during the punching process;
Secondly, in the blanking process, in addition to the matching clearance of the mold Cylindrical guide bush, which has an impact on the blanking gap, the side force during blanking, mold processing, assembly accuracy and other factors also have an impact on the blanking gap. Combining the effects, it should be ensured that the die gap is within a reasonable range of blanking gap.