We have a new press brake in our shop and I am trying to get SolidWorks sheet metal flat patterns to match the blank size from the brake controller (it has been very accurate). We are air bending and using consistent tooling per material thickness.
I am trying to use a gauge table with bend allowance to create the proper flat pattern based on angle. I made a simple part with 1 bend and ran it through the brake software to get its blank size for various bend angles. I then back figured what the bend allowance should be in SolidWorks for the corresponding angle to give me the correct flat pattern dimension for this bend. I know the radius changes with air bending based on the tooling used and angle bent, but as I mentioned we are using consistent tooling and I was hoping to make up for the radius with the bend allowance. For us having the correct flat pattern dimension is more important than radius on the part.
The problem I am having is the table is not working the way I thought it would. I started with a sample table from SW and have filled in some bend allowances for each thickness per angle. The table gives correct flat pattern for the 90 degree bend and nothing else. Any other angle does not seem to be pulling the bend allowance from the table. With the part set at anything but 90, if I change the bend allowance for the corresponding angle in the table it does not change the flat pattern dimension. If I change the bend allowance for the 90 degree angle it changes the flat pattern for all angles. It is as if SolidWorks is using the bend allowance for 90 degrees and then maybe K factor form there.
I must be missing something, am I using the table wrong? Has anyone else found a good way to have their SolidWorks flat patterns match what comes out of a brake controllers software, is there another way to do this?
I have attached my table, any help would be much appreciated
Matt
Matt,
I don't have access to a press brake any longer, but I developed the attached files at one company where we did A LOT of sheet metal. We measured the actual material thicknesses (NEVER trust the published values or use the nominal gauge thickness - probably the single biggest mistake folks make) and measured the flats before bending and the coupon parts after bending. Putting those measurements into the attached spreadsheet we calculated our K-factors. For any new designs in SWX we just looked up the material gauge and inside bend radius and used the appropriate K-factor to generate the flat patterns. We got amazing accuracy with this technique. We were able to pre-punch holes on multi-bend parts and they lined up perfectly in assembly. No more mate-drilling!!
I have to admit that most of our bends were 90 degrees, but I would venture that if you make similar measurements you will get great results, even for other angles.