Selected articles from January/February 2008 issue published on TheFabricator.com:
This article introduces beginning toolmakers, die maintenance technicians, engineers, and press technicians to tool and die components and their functions
Diemakers have several options for slug-pulling problems, such as knockout pins, vacuums, punch or die dulling, oil viscosity, wire EDM hole slots, punch/die clearance changes, edge shearing, mechanical grippers, air jets, and cuped-shaped punches. Another method to help stop slug pulling is bell- mouthing the die, which essentially involves cutting a funnel shape around the hole.
Forming of galvanized AHSS involves higher contact pressures at the tool-workpiece interface compared to forming mild steel. Under these severe interface conditions, improper selection of lubricants, tool materials and tool coatings may result in high scrap rates and galling in stamping production.. Based on SDT results, polymer-based lubricant with EP additives and water-soluble DFL were found to be most effective, Synthetic lubricants showed also reasonably small frictional responses with a PVD coated die in forming GA coated strips.
Each metals has its own blend of physical, chemical, and surface properties and characteristics. Knowing about the major work metals (not tool steels), their properties, grades, and characteristics helps to achieve the best results in stamping and forming best results.
Stamped components are made by forming, drawing, trimming, blanking, or piercing metal—in sheet or coil form—between two halves (upper and lower) of a press tool, called a die. The upper member (or members) are attached to slide (or slides) of the press, and the lower member is clamped or bolted to the bed or bolster. The die is designed to create the shape and size of a component. The two halves of the die are brought together in the press. Both force (load) and accuracy are required to achieve the repeatability and tolerance demands.
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