One of the Sheet Metal Parts (XINGHUI) unavoidable side effects of press-brake operation is frame deformation. We’re bending steel parts with other steel, that of the press brake, which for physical reasons will deflect. In particular, the ram will bow in the center. At that point the punch will be farther away from the die, resulting in a wider angle and yielding a bent profile with a boat-like shape. Even a small angle difference can turn metalforming into a process full of pitfalls.

The deformation described above can be compensated for with crowning, where the table pushes upward to keep the die at a consistent distance from the ram. There are two types of crowning: one uses a series of wedges to raise the die mechanically; the other uses short-stroke hydraulic cylinders embedded into the bench.

But how much crowning is just the right amount? Most manufacturers rely on data tables calculated based on the press-brake structure and sheetmetal characteristics as declared by the foundry. Everything is fine, right? Nope. Actually, this method often does not work because sheetmetal behavior is unpredictable. It has a high variability that depends on a series of factors. Knowing them and, when possible, compensating for them is essential in order to save time and material in tests and samples. Especially today, in an age of smaller batches, obtaining the correct bend angle on the first try is a must.

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