Procurement of a stamping die - yesterday and today

Modern Machine Shop, Sept, 1990 by R.J. Rizzo

Procurement Of A Stamping Die - Yesterday And Today

Yesterday

Not many years ago, the Northeastern portion of the U.S. was an important industrial area. Thousands of metal manufacturing plants were located there, including cast iron foundries, forge shops, machine shops and stamping establishments. Punch press makers such as Bliss, V & O and others were nearby. Even New York City, of all places, housed scores of jobbing shops which built tools and dies for gold and silver jewelry, components for radios, watches and clocks, including replacement parts for automobiles - to name a few. Business was so brisk that tool and diemakers from Europe and elsewhere converged on the area. It was indeed a veritable melting pot.

When a manufacturer needed a die for a stamping, he would send a handmade sample of the part to a nearby friendly job shop for an estimate. Shortly thereafter, he would receive the quote, executed by the foreman of the place. In those days, each diemaker had the responsibility of designing and building tools at his bench - without drawings - a risky business. But those fellows were rugged individualists - master mechanics who seemingly had an unlimited ability to create and improvise, boundless optimism, a generous amount of pride plus a dash of arrogance to match. Imagine, if they broke a tap accidently, their day was ruined and they were unapproachable until the next morning. But beautiful work flowed from the hands of these talented men - despite the meager machine tools and measuring instruments available at that time. I had the good fortune to serve my apprenticeship under such extraordinary and highly disciplined craftsmen.

Years Pass

Gradually, manufacturing of metals moved out of the city and into the suburbs of neighboring states. The tool shops followed. And as each of those stalwart craftsmen passed away, the entire system changed. Tools and dies then had to be designed on paper by ex-toolmakers doubling as draftsmen. As a consequence, manufacturers soon began to send both design and build-work outside. Their own toolrooms served only to maintain the production equipment - much as is done today. And although this system has greatly simplified tool procurement, misunderstandings still occur between manufacturers and tool shops - sometimes leading to litigation.

Today

At present, the tool engineers of manufacturing plants initiate most tool and die designs in order to better control their company's business. THEY, therefore, are the individuals who must watch the specifications which appear on their product and operation drawings, paying special attention to accuracy, unnecessarily tight tolerances and especially to omissions.

For example, an element which is presumably understood in the trade, but absent from a purchase order could cause an unending flow of problems. As a precaution to prevent such a situation, a wise tool engineer recently insisted on adding the following conditions to the usual procurement language when his company ordered the design of a 28-station precision duplex progressive die. Listed here are only eight of a total of twenty conditions: * Serrating and scoring stations to precede pilot hole perforating station. * Above operations to be adjustable with micrometer dials with die in the press. * Do forming upward by cams to insure unimpeded movement of strip through die. * Provide trim punches with ejector pins to control slugs. * All round punches, pilots and springs to be removable through punch holder. * Interlock middle punch and die sections in chases to provide added precision. * Provide four heavy bumpers at guideposts to insure parallel die closure. * All notching punches to be guided in solid stripper to prevent flexing.

Although these conditions raised the cost a bit, the die was designed, built and run without a single problem.