What grinding process has been changed to increase the edge life of punches by a factor of 5?

"Ugh, this drop punch needs to be repaired again!"

"This punch is made of tungsten steel, the normal life should be 500,000 times, why the edge part is worn out after 10,000 times?"

After hearing several complaints from the production technician, our engineer removed the old punch and started to think about.

After some confirmation, the original tungsten steel punch has a shaped edge due to its shaped , and in order to make the size of the punch meet the accuracy requirements, the engineer used a precision discharge process to finish the shape of the edge of the punch.

Precision electrical discharge machining based on tungsten steel is characterized by high accuracy, but the electro-etching surface becomes brittle and prone to chipping and wear, reducing the life of the punch. Moreover, the discharge process is time consuming, which leads to high overall cost of repairing the punch. If you still use the original discharge method to repair, it need to open the CNC machine again to redo the new electrode and then discharge processing, the whole process is too long, and the punching machine has to be in the state of waiting for material shutdown for several days!

"How should this be done?" Seeing that the delivery time was imminent, Engineer Yi made his suggestion that by using a process that does not destroy the original properties of tungsten steel to treat the cutting edge, we can maintain the wear resistance of the punch and extend its service life. After analysis and discussion, Yi proposed a high precision grinding process instead of a precision discharge process. Of course, the shape of the cutting edge of the punch should be adjusted to fit the grinding process without affecting the size of the product.

It took Yi two hours to update the drawing of the punch. After the production technician polished off the original worn part, the production technician directly used a precision grinder to grind and process the cutting edge part of the punch according to the updated version. And the punch was repaired after only 3 hours of standby.

After reworking the punch with the precision grinding process, the edge will only show slight wear when it is used 50,000 times. Compared with the previous frequency of needing to be reworked once after 10,000 times of production, the life of the edge of the punch after reworking with the grinding process proposal is increased by 5 times, which saves the number of times and cost of maintenance and increases the production efficiency.

Digging into every detail in the production process, reducing our tooling cost from the subtle process improvement proposal, thus creating profit for our customers - this is not only the action policy of our KANOU people, but also the permanent mission of every ironworker in our career!