Page 18 - MetalForming September 2010

The Art and Science of
In-Die Tapping
While in-die tapping (IDT) can offer we’ll focus on mechanically driven IDT
phenomenal cost-saving oppor-
tunities for stampers, it continues to be one of the more intricate and per- plexing operations occurring within stamping dies. Although IDT products have been commercially available for 20-plus years, only a small handful of designers and toolmakers have mas- tered the art. Add in the immense pres- sure to reduce overall design-and-build cost and the use of IDT can fall out due to corner-cutting. Furthermore, although CAD and CNC technology are magnificent resources, there’s still a certain amount of tool-making method- ology and passion needed to ensure proficiency and success with IDT.
Although it’s possible to drive an IDT application by several different auxiliary-power approaches, including servo-mechanical and hydraulic, here
Ray Osborne, business development man- ager for Anchor Danly (www.anchor- danly.com), dedicates this article to the memory of the late Graham J. Clarke— colleague, friend and crusader for the art of in-die tapping.
designs. The very same fundamentals and principles that apply to rock-solid die design, reliable die construction and trouble-free die operation also apply to attaining success (and handsome profits) with IDT. So, let this article serve to debunk the myth and mystery of IDT once and for all.
Timing/Sequence
Let’s break down the IDT process:
• Advance the strip into progression and engage the strip with the pilot punches
• Clamp the strip
• Deliver forming lubricant to the working end of the tap
• Tap the part
• Retract the tap and unclamp the strip
• Disengage the pilot punches from the strip
• Repeat
Attempting to employ any timing/ sequence in an IDT installation other than the aforementioned will almost certainly lead to problems, such a bro- ken tap, poor thread quality, damaged
14 METALFORMING / SEPTEMBER 2010
www.metalformingmagazine.com
Stampers should not consider in-die tapping (IDT) as black-box technology; rather, an IDT installation must function in harmony with the die, press and the material- feeding systems around it. Here’s everything stampers need to know to make IDT work for them.
BY L. RAY OSBORNE