Punch type is multi-clock variety, the type of choice is mainly based on finished stamping materials, specifications, finished product size, size, requirements of these comprehensively selected. Punch itself is a large collection of processing equipment. Therefore, customers choose according to their own products to be manufactured, stamping die type, stamping process characteristics, production efficiency and investment budget to targeted selection to ensure that the purchase of the punch really play their actual production efficiency. Then select the punch need to pay attention to two aspects? Small series here to briefly introduce one or two.
First, the choice of punch type
Normally, it is recommended to use open punch from small metal blanking parts, bent parts or shallow drawing parts. Open punch flexible body deformation will destroy the die gap evenly distributed, affecting the accuracy of stamping finished products and reduce die life. However, its body is open on three sides, easy to operate, easy to install molds, feeders, automatic die changeover device to achieve automated production, and the price is affordable, so for small and medium pieces of stamping recommended open punch.
For large and medium-sized or high precision stamping products, door-type punch and biaxial punch should be used. For leveling, bending correction, shaping and other special stamping process, you should use a punch with high strength and rigidity.
Second, the second is the choice of punch size
Select punch size specifications related to the tonnage punch, the maximum closing height, punch speed and punch table size of these four areas:
1, the choice of punch tonnage
The selected punch tonnage must be greater than the actual stamping press production pressure, and must ensure that the workpiece load curve can not exceed punch permissible load curve. The usual tonnage selection principle is as follows:
Punching, bending correction, the maximum stamping force of not more than 80% of the tonnage 90%; deep drawing, the maximum drawing force of not more than 50% of the tonnage of 60%; shallow drawing, the maximum drawing power is not greater than Tonnage of 70% to 80%.
Blanking bending or blanking deep drawing composite stamping, depending on their specific circumstances and the allowable load curve of the machine used to determine the tonnage value.
For thicker stampings, not only to consider the press allowable pressure, but also to consider the size of punch power.
2, the selection of punch table
Punch table to be based on the actual size of the mold to be installed, if the mold can be based on customer demand to increase the size of the work surface.
3, the maximum closed height of the selected
The choice of punch, stamping die closing height should be between the maximum closing height of the punch and the minimum closing height between.
As the connecting rod wear will be shortened, the future repair mold will reduce the closing height of the stamping die, stamping die design stamping die when the height is generally taken close to the maximum punch height.
4, punch stroke and press speed selection
This is usually based on the actual stamping process to determine, manual manual feeding, do not choose too much stroke number of punches; automatic stamping, as much as possible to choose the stroke more presses. Deep drawing, you can not use too much stroke number of punches, because the drawing too fast, too late deformation of the material, parts easily cracked.