Page 48 - MetalForming March 2011

Tooling by Design
is performed routinely, to avoid sharp edges on thousands of consumer items. Even difficult-to-form materials can bend to a near-zero inside radius, by coining or scoring prior to bending.
Again, the above statement would be true if it began like this: “To avoid increased die complexity and higher tooling costs, ...”
5)The final part radius at the flange
of a drawn shell must be equal to or greater than five-times the material thickness.
This is perhaps the biggest half- truth in our industry, because it actu- ally is half true. An insufficient draw radius may cause the part to split as the material deforms, due to the high restraining forces developed as the
Producing a drawn shell with a tight flange radius is entirely possible.
workpiece material bends and unbends over the tight radius. Drawing over a tight radius also produces a tremen- dous amount of heat, leading to micro- scopic welding of the sheetmetal to the tools.
However, these are process param- eters related to the die; they are not product-design parameters. Produc- ing a drawn shell with a tight flange radius is entirely possible. First, the stamper must draw the shell slightly deeper than the final product dimen- sions, while using the die radii neces- sary to carry out the deep-drawing process. In a subsequent operation, the shell height then is reduced by compressing it and forcing the excess material to flow into the tight corners of the die. This practice produces a much tighter radius, per the illustration (cour- tesy of Arnold Miedema).
Please share with me your own industry legends, myths or half-truths: pete.ulintz@toolingbydesign.com.MF
Don’t get caught behind the 8 ball
Have you been wanting extra copies of an article published in MetalForming for your own promotional efforts— trade shows, meetings, mailings, etc ?
Reprints are cost effective and will produce a high-quality piece of literature for your particular needs.
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connect everywhere
Network your factories and offices with SmartPAC 2 and LETS (Line Efficiency Tracking Software)
Take advantage of
SmartPAC 2’s built-in Ethernet connectivity to communicate over your network.
Send and receive text messages, display setup sheets stored on a central server, back up your tools to a remote location, and view pressroom status over the network and internet. When you connect your equipment to LETS, you can collect production data, feed critical parameters reports automatically, view machine status in real time, and schedule a prioritized job queue for each machine.
To learn more about Wintriss Controls, please call 1-800-586-8324 or visit www.wintriss.com. ®2010 Wintriss Controls. All rights reserved.
46 MetalForming/March 2011
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