Sheet Metal Stamping Simulation

This is a good question and certainly worth further discussion. When assessing wrinkles in forming simulation, it is important to understand how a wrinkle is "displayed." A serious wrinkle (i.e.: metal folding, scrunching together) will show up very clearly. If the material is predicted to fold, within the FEA mesh of the simulation, folding will be observed very clearly.

To many toolmakers this may seem a simple question, however, for those new in the industry or without much experience, it is worth explaining in more detail. A crash form means that a male punch and a female die are closed together without any springs, cushions or otherwise to hold the blank as the forming process takes place. The punch and die simply "crash" together.

The method is successful on simple, shallow parts with basic shapes. Basically, the flow of material cannot be controlled in this method, and that is why wrinkling results in deep parts.

We would like to explore the capabilities of forming simulation, as well as provide some descriptions of how the technology works. So here is a quick summary of a few typical applications of press forming simulation technology. Being aware that press forming simulation is actually a specific application of the Finite Element Method (FEM also known as FEA) may assist your understanding.

It is common practice for a toolmaker to scribe or etch a grid of circles onto a blank during the tooling development stage. Then, the etched blank is put in the nearly finished tool (or proto-tool) and the sheet metal is formed. As the forming takes place, each circle (which was perfectly round with a known diameter, when it was etched onto the blank) stretches according to how much strain is experienced at that point, as determined by the shape of the part and properties of the blank material.

Recently, we spoke to a customer and asked him a series of questions, regarding StampingSimulation.com services. Here is the transcript of the interview.

This is the topic that most toolmakers want to know about when the use of forming simulation is suggested. Before discussing this topic, it is important to understand what the intent of forming simulation is.

A common misconception is that forming simulation software is a magical tool that is supposed to replace die designers' and toolmakers' years of experience. There is often a misunderstanding that such software can automatically design perfect dies with 100% success. This most certainly is not the intent of forming simulation software.

It is important to understand the difference between the calculation methods used in sheet metal forming simulation. The term INCREMENTAL and ONE-STEP refers to the calculation method used to solve the forming simulation mathematics of a sheet metal forming simulation problem. It is important to understand the difference between the two calculation methods and to understand when it is appropriate to use each method.

It was not really that long ago that parts and tools were designed by using a drawing board and a T square. Of course, CAD came along and changed the way engineers drew and designed. Initially, 2D CAD simply made the drawing board electronic. While this in itself was a huge step forward, it was soon trumped by 3D parametric modelling.

Western sheet metal parts suppliers are under immense pressures from lower-cost Chinese parts producers and need to improve efficiency to strengthen their chances of survival. Today, Automakers call their suppliers and say, "What are you going to do to meet the China price?"

So what happens if your part is unlikely to be successfully formed in a single stage? What if you want to see what would happen if you TRIED to form it in a single process?

The most important aspect of any forming simulation is the CAD model and it all starts with the blank shape estimate. In order to perform the blank shape estimate, a complete CAD model of the final part shape is required. By complete we mean complete with surfaces and fillets (or rads).

When using a tool like AutoForm to design die faces, with the intent of simulating the design for verification, there is a basic path, or set of steps, that is used to create a die face design. We will now briefly out-line these steps.

You may not be aware of it, but StampingSimulation.com can provide customers with tooling surfaces (die face data), rather then just a simulation service.