Page 44 - MetalForming April 2012

Tooling by Design By Peter Ulintz
History of the Progressive Die
Tooling Technology
Prior to the discovery of metals, people used simple hand tools made from bone, rock and wood. Following the discovery of fire, humans learned that adding
heat to certain rocks (ores) would free the metal from the
rock. Eventually, the art of extracting and smelting metals
and forming them into usable objects evolved—commonly referred to as metalworking.
Metalworkers were valuable members of early societies. As more and more products and tools began to be made from metals, society needed more people skilled in the craft of met- alworking. Objects made from metals were necessary for indus- try, farming, jewelry-making and defense purposes.
Old coins reveal that the art
of die sinking—a process that creates a cavity, or opening, of a specific size and shape for cast-
ing or forging—was known to the ancient Greeks at least back to 800 B.C. (ref: J.L Lewis, Dies and Die Making, Journal of Commerce, 1897). However,
Peter Ulintz has worked in the metal stamping and tool and die indus- tries since 1978. He has been employed with the Anchor Manufacturing Group in Cleveland, OH, since 1989. His back- ground includes tool and die making, tool engi- neering, process engi-
neering, engineering management and product development. Peter speaks regularly at PMA semi- nars and conferences and maintains the website, www.ToolingbyDesign.com. The site serves as a web-based source for the transfer of modern met- alforming technology and the advancement of “Performance-Based Die Engineering Strategies.” Peter Ulintz
pete.ulintz@toolingbydesign.com www.toolingbydesign.com
these artifacts do not show that the use of punches and dies was equally known.
stamping operations came with the development of the progressive stamp- ing die. A book by Oberlin Smith titled,
The Press Working of Metals ( Wiley and Sons, 1896), describes “follow-on” tooling and “successive gang cutting” in a manner that suggests that they may be early predecessors of the progressive die. The 1897 book by J.L. Lewis contains the earliest published record I could find to a progressive die.
The use of progressive dies during the first half of the 20th century was limited primarily to companies producing their own products in very high quantity— electric-motor components, for example. The first edition of the Die Design Handbook (Ameri- can Society of Tool and Manu- facturing, 1955) contains an entire chapter on progressive dies, and offers numerous exam- ples and illustrations of progres-
sive-die designs and die strips for such parts.
After World War II, the U.S. econo- my surged. Most contract manufac- turers of the time produced metal stampings in single-operation dies and presses. Operators hand-fed strip material into presses equipped with blanking dies. Blanks dropped into containers that were then delivered to subsequent hand-fed press-and-die forming and cutting operations.
As production demand increased, speed became increasingly important. At the same time, concern for operator safety grew, as manual loading and unloading of parts from the dies creat- ed hazards. By the 1950s, single opera- tions in single presses made it difficult to keep up with rising production demands.
In 1953, Ed Stouten and his partner
Upper die Blank Lower die
Anvil
Eventually, coins were struck using two coining dies: a lower die depicting the coin in a negative form and a com- panion upper die. A metalworker placed a blank between these two dies and the upper die was struck with a heavy hammer, rendering a positive image on the blank (Fig. 1). The ham- mer method was used well into the Middle Ages. Even today people occa- sionally speak of coins being “struck.”
The first record of punches and dies being used in a machine having guides (or ways) to ensure punch-die align- ment appears in the 15th century, when a German locksmith used the process to manufacture hinges. In 1796, a Frenchman named DeVere earned a patent for “Dies for Punching and Drawing Sheet Metal,” perhaps the first of its kind.
A significant advancement in metal-
42 MetalForming/April 2012
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