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 metal forming simulation technology. Being aware that metal forming simulation is actually a specific application of the Finite Element Method (FEM also known as FEA) may assist your understanding.
Splitting, thinning and wrinkling checks.
It goes without saying that the primary purpose of the forming simulation step is to check how the material behaves prior to machining of any tool steel.
The results produced in the forming simulation step illustrate very clearly the calculated areas of material yielding (splitting), amounts of necking (thinning or changes in thickness) and areas of material compression (wrinkles and folds). The Forming Limit Diagram (FLD) is key to analyzing this data as it plots each element’s strain (in major and minor axis) on a graph and compares it to the material’s limits to determine if any of these defects will be present. With this information in hand, countermeasures and adjustments are made to the die face design and then the forming
simulation is re-run, until each defect is removed or an acceptable result is achieved.
Multiple-stage forming.
If a part cannot be formed in a single stage then each subsequent stage can be simulated and checked too. It is simply a matter of taking the result from each previous stage and feeding it into the next. The previous stage results may include a draw, a trim, a hole pierce or any other operation, each of which gets carried over into the next stage’s simulation.
Pierce hole roundness checks.
You may have realized already that it is possible to simulate a forming process with a hole pierced in a blank. This gives an accurate simulation demonstrating whether a hole can be safely pierced in a blank stage, then drawn, without losing its roundness or desired position (usually determined by the quality specification of the final part). Conversely, such a simulation may show that an unimportant hole will go “egg shaped” after forming, but if acceptable, it can remain as a hole pierced in the blank, as opposed to piercing it last, when maybe a cam unit or something else would be required.
Spring back check.
A springback check can be performed after any stage, for example, after the first draw stage or after the final stage. The end result is not just a number on paper of the amount of springback, but a full 3D CAD model of the part in the sprung back state (that can be exported in any CAD format). This means it is very easy to use this data to counteract the spring back or decide if the amount of spring back is acceptable or not.
Splitting, thinning and wrinkling checks.
It goes without saying that the primary purpose of the forming simulation step is to check how the material behaves prior to machining of any tool steel.
The results produced in the forming simulation step illustrate very clearly the calculated areas of material yielding (splitting), amounts of necking (thinning or changes in thickness) and areas of material compression (wrinkles and folds). The Forming Limit Diagram (FLD) is key to analyzing this data as it plots each element’s strain (in major and minor axis) on a graph and compares it to the material’s limits to determine if any of these defects will be present. With this information in hand, countermeasures and adjustments are made to the die face design and then the forming
simulation is re-run, until each defect is removed or an acceptable result is achieved.
Multiple-stage forming.
If a part cannot be formed in a single stage then each subsequent stage can be simulated and checked too. It is simply a matter of taking the result from each previous stage and feeding it into the next. The previous stage results may include a draw, a trim, a hole pierce or any other operation, each of which gets carried over into the next stage’s simulation.
Pierce hole roundness checks.
You may have realized already that it is possible to simulate a forming process with a hole pierced in a blank. This gives an accurate simulation demonstrating whether a hole can be safely pierced in a blank stage, then drawn, without losing its roundness or desired position (usually determined by the quality specification of the final part). Conversely, such a simulation may show that an unimportant hole will go “egg shaped” after forming, but if acceptable, it can remain as a hole pierced in the blank, as opposed to piercing it last, when maybe a cam unit or something else would be required.
Spring back check.
A springback check can be performed after any stage, for example, after the first draw stage or after the final stage. The end result is not just a number on paper of the amount of springback, but a full 3D CAD model of the part in the sprung back state (that can be exported in any CAD format). This means it is very easy to use this data to counteract the spring back or decide if the amount of spring back is acceptable or not.
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