April 10, 2007
Figure 1 Pinch trimming die design Various specialty metal cutting methods are used in stamping operations. Among them are pinch, breakout, and shimmy. Pinch Trimming Pinch trimming is a special method in which the vertical walls of a drawn or stretched vessel are cut by pinching...
March 13, 2007
How tool steel is machined can make a big difference in its performance and life. A poor grinding job might look good, but unseen stress can cause premature failure.With the correct grinding and wire burning techniques, tool steel results can be optimized.
February 13, 2007
Slug pulling, which occurs when scrap metal—the slug—sticks to the punch face upon withdrawal and comes out of the button, or lower matrix, is a serious problem that can damage parts and dies. Various methods can help reduce the occurrence of slug pulling. Air Vents Putting air vents in...
February 13, 2007
Numerous factors contribute to the premature failure of piercing and cutting punches. In addition to problems with the punches, such as tool steel or problems caused by EDM and grinding, the press can cause problems through deflection, and bridge strippers also can cause punch breakage.
January 9, 2007
Cutting shear, or the angle ground into the end of a punch, has a big effect on punch deflection and breakage, as well as press tonnage required. Retainers, which hold the punch to the die shoe, also are important. The backing plates, ball lock punch retainers, and headed styles of punches and retainers all require careful consideration.
December 12, 2006
Slug pulling is a serious problem in a stamping operation. Addressing the issue requires first understanding why the slugs are pulling. What Is Slug Pulling? When a pierce punch creates a hole, it also produces scrap, usually referred to as a slug. Slug pulling occurs when the slug sticks to the...
October 10, 2006
Cutting is the most severe metalworking process that takes place in a die and shouldn't be taken lightly. Cutting Basics Cutting metal requires great force. For example, it takes approximately 78,000 lbs. of pressure to cut a 10-in.-diameter blank from 0.100-in.-thick mild steel. Consequently,...
October 3, 2006
Editor's Note: "Setting Up Progressive Dies" is a two-part article. Part I discusses press and die cleanness, die alignment, clamping procedures, and preliminary shut height calibration. Part II discusses the process for getting metal into the die, setting the pitch, feed release, and other factors...
August 8, 2006
A stamping die is a special, one-of-a-kind precision tool that cuts and forms sheet metal into a desired shape or profile. Most dies are constructed of several basic components, including die plates, shoes, die sets, guide pins, bushings, heel blocks, heel plates, screws, dowels, and keys. Dies also need stripper, pressure, and drawing pads, as well as the devices used to secure them—spools, shoulder bolts, keepers, and retainers; and gas, coil, or urethane springs.