“What the …? This can’t be done!”
How many times have you heard that expression? Or seen someone scratching his head in bewilderment when trying to decide which flange to form first or last, not unlike the operator pictured in the lead photograph?
Carefully planning the [glossary]forming order[/glossary] can make even the most daunting project less complicated and problematic. Sure, we’ve all been there; but before we encounter this problem again, let’s look for some viable solutions. Where do we start? With the blueprint, of course.
First things first, review the [glossary]blueprint[/glossary], either customer prints or [glossary]flat pattern[/glossary] prints from a [glossary]CAD[/glossary] system (or both), and compare them to the actual workpiece. Once you are sure they match, the fun begins. Start by marking the actual part with [glossary]bend lines[/glossary] and dimensions as shown in figure 1.
For example, show upward-bent flanges as solid lines and downward bends as dotted lines.
The marked part will be used for forming reference at the press brake. Second, do a line drawing to scale on a separate piece of paper, excluding the dimensions (see figure 2).
Now, use your [glossary]tooling profile[/glossary] stencils or the actual tools themselves to find the strongest punch profile, available that will achieve the desired results. The strongest punch profile, is the punch that will handle the most tonnage. In other words, don’t use a [glossary]gooseneck[/glossary] punch if it isn’t necessary. Over time, selecting punch profiles by this method will save tooling life, adding years to the tooling.
Once you have selected the punch profile by matching tool profiles with the line drawing, make a note of the direction of the punch when placed in the ram, e.g., gooseneck facing toward you or facing away and add that information to the [glossary]setup sheet[/glossary] for future reference.
Because we now know the ideal punch profile and which bend needs to be made last, it is relatively easy to decide the remaining forming order. Note whether the V-die needs to be toward the front or back, assuming double V or quick-change V-die.
At this point you must decide which [glossary]tool holders[/glossary] and die bolster are to be installed into the press brake (see figure 3). This is done using exactly the same process as the punch profile selection.