Page 82 - MetalForming October 2011

Tooling Technology
Zero Defects with
Problematic Dies
Mistake-proofing in the pressroom is a key element to consistently producing the highest quality products. Here we present three examples of stamping companies faced with problematic tools, and the solutions that eliminated defects at the press.
BY DREW STEVENS
While not every stamping com- pany can build smart dies that adjust themselves, or use RFID-enabled cribs to track supplies, there are two constants that affect every metalforming company in the world: poor-quality parts and unplanned downtime. Smashed dies and bad parts affect everyone, from managers who must explain a late shipment to a cus-
Drew Stevens is a journeyman tool and die maker and automation engineer, and is author of the book, Die Protection for Lean Manufacturing: Error Proofing Concepts for Toolmakers and Die Designers. Order the book at www.pma.org/marketplace.
Fig. 1—Exact Tool & Die installed four sensors in this die to detect the presence of a broken tap in the strip. Because the sensors use background suppression, only the tap will be detected. This eliminates the chance of nuisance faults caused by any other die components.
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tomer, to a production scheduler who must find time to complete a run after the toolroom has put in extra hours to repair broken dies and create fixtures to rework bad parts.
Case I: In-Die Tapping
and Detecting Broken Taps
Exact Tool and Die, Inc., a medium- sized manufacturer on the west side of Cleveland, OH, began in 1978 as a builder of new tooling for stamping companies, entered the stamping busi- ness in 1993, added an assembly area
and, most recently, added a waterjet- cutting cell to its list of capabilities.
Exact’s Robert Matis, who heads the firm’s design team, describes a recent project: stamping a part, to relatively high volumes, with four tapped holes. While piercing and extruding a hole to be tapped offline is certainly not a new concept in stamping, performing the tapping operation in the press can pose a challenge—reference Ray Osborne’s article on in-die tapping (IDT) in this issue. To tackle the project, Matis’ design team decided to use an IDT system (from