Mr. Zhou asked: We’re punching 3-millimeter holes in 3-millimeter stainless steel mesh. We can currently use SKH51, but it’s not very durable—it only lasts for about 10,000 to 20,000 punches. Since we specialize in making sieve mesh, replacing broken punches is quite a hassle.
That’s right. When punching mesh with densely packed holes, the punches tend to break after 10,000 to 20,000 cycles, requiring replacement. These frequent shutdowns to replace punches aren’t just costly—they also lead to low production efficiency, meaning you can’t get much work done in a day, resulting in even greater losses.
So, when a punch breaks, you lose more than just the cost of the punch itself. The labor costs wasted on having workers replace it are far higher than the cost of the punch; the loss in output value due to production delays is far greater than the cost of the punch; and an order that should have been profitable ends up as a money-losing venture simply because the punch breaks too quickly—which is even worse than having no business at all.
Punching 3mm mesh holes in 3mm stainless steel—where the punch diameter equals the sheet thickness and the punch-to-sheet ratio is 1:1—places extremely high demands on the punch material’s resistance to fracturing. Given that this involves punching 3mm-thick sheets of hard stainless steel, the punch is even more prone to breaking due to vibration.
SKH51 is a tungsten-containing high-speed steel with a hardness of 62–64 HRC and excellent wear resistance. However, it is hard and brittle. Under such harsh conditions with a punch-to-sheet ratio of 1:1, the punch is prone to breaking. The fact that his punches now break after just 10,000 to 20,000 strokes further confirms this.
For stamping 3mm mesh holes in 3mm-thick stainless steel—a demanding application involving thick, hard material with a stamping ratio of 1:1—I recommend 8566 anti-chipping steel.
8566 is a proprietary anti-chipping steel from Yuhui Mold Steel, primarily designed to address mold chipping issues. 8566 offers four times the chipping resistance of high-speed steel SKH-9 and twice that of D2, with a hardness of HRC 58–60. It can resolve chipping problems that high-hardness mold steels such as D2, DC53, and SKH-9 cannot solve; In particular, under demanding conditions such as stainless steel stamping, thick-gauge sheet metal stamping, fine-blanking dies, sharp-corner stamping, narrow-flange stamping, and stamping where the hole diameter is smaller than the sheet thickness or the stamping ratio is less than 1:1, 8566 die steel effectively resolves die chipping issues and significantly extends die life.
Mr. Shi was punching 1.1-mm holes in 1.2-mm-thick stainless steel that had been cold-headed. The punch diameter was smaller than the sheet thickness, and the punch-to-sheet ratio was less than 1:1. The working conditions were more severe than Mr. Zhou’s, and since the stainless steel had been cold-headed, the material was very hard. The original punches were made of DC53, SKH51, M35, M42, and PM23—all of which broke very quickly, making punching impossible. However, with the 8566 punch, 40,000 punches could be completed in a single run, allowing production to proceed smoothly. The difference in results was like night and day.
Then there’s Mr. Wang, who was punching eight large mesh holes in 5mm stainless steel. Each sheet required 6,000 holes. He tried ASP60, ASP30, 3V, and DC53 punches, but they all broke, making production impossible. However, using the 8566 punch, he was able to punch six sheets in one go—a total of 36,000 holes—without any breakage.
This 5mm-thick stainless steel is much thicker—and much harder to punch—than Mr. Zhou’s 3mm stainless steel. Yet the 8566 chipping-resistant steel can punch 36,000 holes in a single run, whereas SKH51 punches break after just 10,000 to 20,000 holes—that’s a twofold increase in performance.
Therefore, if you’re punching 3.0-mm stainless steel mesh holes in Mr. Zhou’s 3-mm material and your SKH51 punches break after just 10,000 to 20,000 cycles, you should try the 8566 anti-chipping die steel. When it comes to punch chipping, using 8566 die steel makes all the difference—it’s like night and day.
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I am Wu Dejian, the “King of Mold Steel,” from Dongguan Yuhui Mold Steel. Yuhui Mold Steel is used by three Fortune 500 companies, and Kyocera has been sourcing our products for seven consecutive years. I have helped over 4,000 companies solve complex challenges related to mold material selection, manufacturing, and usage. If you’re unsure about which mold steel to choose, or if the steel you’re currently using results in short mold lifespans, or if you’re unsure which material to use, feel free to reach out to me. I’m confident I can serve as your trusted advisor in this area and help you avoid costly mistakes. Wu Dejian Mold Steel—your trusted advisor—and customers who’ve tried us keep coming back!