Forming in a die can be stressful, not only to the designer and operator but especially to the material being formed. Whether you need to do a deep-draw form or create a deep form in a multicontoured part, the principal factors determining the strength of the form, repeatability, and success are the same — tension, compression, and stretching.
There are a variety of ways to produce a large form, whether it is simply a large flowing form or a deep draw. An operation is defined as a deep draw when the height of the form is greater than the diameter or width of the form.
Each material has its own limits, and you can only do so much within the confines of those limits. Understanding the limiting draw ratio (LDR) of the material and the objective for the product during the design phase is crucial and will give the engineer the best opportunity to match the final product to the design intent.
Whether your material is a cup or blank and you run a transfer press or coil-feed a strip into a progressive die, the fact of the matter is that material is material. Cracking, tearing, work hardening, wrinkling, and fracturing are going to occur at some point.
Read the full article in The Stamping Journal.
October 22, 2020