Question from a viewer during the 295th live stream: What is the best die material for punching holes in 3mm-thick aluminum sheets?
Punching and cutting 3mm-thick aluminum sheet involves stamping thick aluminum. The punching process can easily generate aluminum shavings that cause material jams. Therefore, you should select a die steel with high-quality smelting that is free of microscopic cracks and does not stick to the material, while also offering fast heat dissipation. Wear resistance is the least important consideration, as aluminum is inherently soft; a hardness of 58 HRC or higher is sufficient.
Based on these performance requirements and past experience, I recommend 8566 anti-chipping steel.
8566 die steel offers four times the chipping resistance of SKH-9 high-speed steel and twice that of D2, with a hardness of HRC 58–60. It can resolve chipping issues that high-hardness die steels such as D2, DC53, and SKH-9 cannot address; In particular, under severe conditions—such as stainless steel stamping, thick-gauge sheet metal stamping, fine-blanking dies, sharp-corner stamping, narrow-flange stamping with minimal overlap, and stamping where the hole diameter is smaller than the sheet thickness or the stamping ratio is less than 1:1—cracking issues that conventional die steels cannot resolve are all successfully addressed using 8566 anti-cracking steel.
Mr. Bao said happily, “When punching 4mm aluminum sheet with 8566, it doesn’t stick to the aluminum even after more than 10 days of operation. The punching speed has now been increased to 200 strokes per minute. No other die steel besides 8566 can achieve this—it’s amazed even the industry leaders.”
Mr. Bao was punching 4mm-thick aluminum sheets. He previously used DC53 and SKH-9 for the 45°-angled punches, but they were prone to chipping, and aluminum powder would easily stick to the punches. With a progressive die running at 100 strokes per minute for 10 hours a day, the punches would last about one day—sometimes requiring two replacements a day, which was incredibly frustrating.
However, after switching to 8566 die steel, the punch life improved from requiring two replacements per day to lasting over 10 days without replacement—a more than 10-fold increase in service life. The stamping speed also increased from 100 strokes to 200 strokes per minute, effectively making one day’s work equivalent to two days’ output. This represents a win-win scenario with improvements in both efficiency and service life.
Based on Mr. Bao’s experience, and given that this user is punching holes in 3mm aluminum sheet, I recommend using 8566 die steel.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.