As elaborated in the article “Shaving Operations” featured in MetalForming Magazine, intricacies of shaving in stamping applications, particularly when precision square-cut edges and tight dimensional tolerances are paramount. While shaving operations are commonly associated with punched round holes, they can extend to free-edge features as well.
In the realm of hole-shaving, it’s customary to remove approximately 10 percent of the sheet thickness for most applications. This approach ensures optimal edge conditions while retaining enough material in the “scrap ring” for slug retention—an aspect critical to shaving operations.
A common misconception among diemakers and tool engineers is that reducing punch-to-die clearance to minimize the length of the fracture zone will alleviate shaving-related issues. However, this often leads to more complications. A tighter punch-to-die clearance results in a larger shear band and a smaller fracture zone, accompanied by increased cutting force, friction, and process heat. This, in turn, leads to punch fatigue, chipping, and accelerated punch wear. Tighter clearances also introduce burrs that disrupt accurate part positioning over the shave-die opening and hinder efficient scrap shedding.
The key lies in determining the appropriate punch-to-die clearance in the punching station—one that yields a high-quality shear band and a clean break edge without generating a burr. These engineered clearances, often around 10 to 15 percent per side, depend on material thickness and type, ultimately optimizing tool longevity and minimizing work hardening within the hole.
To delve deeper into the art of shaving in stamping and gain valuable insights, read the full article here: [Link to Source Article]
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Photo and article with all rights reserved, courtesy of metalformingmagazine.com.
