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Press Brake forming without Tooling Marks

Question asked by Bernie Daraz on Apr 27, 2017
Latest reply on May 31, 2018 by Bob Deschenes

Hello All!


I created this process some 25 or 30 years ago before Amada came in and showed us their new tooling style. Back then we used to bend jobs with expensive rubber sheeting to avoid press brake marks, we had some serious customers that wanted their products to look great.


Well before I started using SW, well before SW was created too.


The rubber sheeting was expensive so we avoided its use as often as possible, not only that was it wasn't consistent and needed replacement as the material lost its flexible and protective properties and the bends (air bending) changed. We were constantly 'moving' the rubber sheet to a 'new' section. Then I had this idea. Why not bend over a piece of scrap or waste thin sheet of stainless steel. That worked but we had to cut many pieces of what became know as 'shims'. My boss (one of the greatest guys in the world by the way!) sort of winced at the waste but was happy with the results. One of the things that bothered me was the additional handling so bending took longer. I'm really a lazy guy!


(It's interesting to note that a piece of 1/8" thick 5052-H32 aluminum also provides a mark free way to bend 3/8" diameter stainless steel rod. I used a 1/4" dowel pin (because its heat treated) tack welded to a top punch, it was just a piece of 1/2" bar stock of course. Use a v-die of a sufficient width to accommodate your needs.)


It was also interesting to note that we didn't have to use a larger V-Die to accommodate this process.


I decided to cut some one use shims and bend them as shown in the video attached. They moved and fell to the floor on the first bend and I laughed at myself! Then I immediately thought about using duct tape to act as hinges at the ends of the moving 'pads'. You'll have to imagine the tape being there I guess. I show the 'pads' being longer than the actual bend so I guess you can't form using this method 'over the edge' of a pad or over the duct tape 'hinge' as it would then damage it.


This method also works on standard tooling, the picture shows that. Please ignore the fact that an Amada punch (top die) is shown.


Within the zip file attached I have the files (SW 2015) for the assembly and an .avi file that can be opened using the Windows Media Player. I cheated and used two pieces of the 'formed' part because I have yet to try out the flex feature.


I'd respect your comments about the process.