Method for determining the fitting clearance and shape tolerance of guide post and guide sleeve

Guide bush and guide sleeve is a kind of mold accessory material commonly used in molds. There are many kinds of mold guide post and guide bushings. When we need mold guide post and guide bushing, how do we choose the mold guide post and guide bushing that suits us? Next, Hengtongxing mold accessories will teach you how to choose Mold guide bush and guide sleeve.

Method for determining the fitting clearance and shape tolerance of guide post and guide sleeve

The method of determining the fitting clearance and shape tolerance of guide post and guide sleeve. The idea and method steps are as follows when designing the guide bush 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 convex and concave molds is one-half to one-third of the change, and the bending deflection of the guide post is one-quarter 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 guide post and the size of the lateral force during punching (mainly when punching unclosed parts);

4. Determine the maximum fit gap of the guide bush and guide sleeve according to the amount of change of the allocated fit gap to the blanking gap and the layout of the guide bush and guide sleeve;

5. Determine the minimum fit clearance of the guide post and guide sleeve according to the maximum fit clearance of the guide post and guide sleeve and the machining tolerance of the guide post and guide sleeve;

6. Determine the geometric tolerance of the guide post and guide sleeve according to the minimum fit clearance of the guide post and guide sleeve.

Teach you how to choose

The principle of choosing the matching accuracy of the mold guide bush and sleeve is that the matching gap of the mold guide bush and guide sleeve should be less than the gap between the convex and concave molds, and how to choose the fit of the mold guide bush and guide sleeve 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 gap between the mold guide bush and guide bushing, the side force during the blanking, the mold processing, and the assembly accuracy also have an impact on the blanking gap. These factors have an impact on the blanking gap. The influence should be integrated to ensure that the die gap is within a reasonable range of blanking gap.