4 Replies Latest reply on Mar 20, 2012 9:18 AM by Bernie Daraz

    RELIEF FORMING

    Emmett Sjoberg

      I have a problem trying to get the correct amount of

      relief in a box so that when formed up it's not binding.

      The box is 6.0 x 6.0 with 1.0" ouside flanges. 11 ga hrs (.119).

      First I tried making the box with a base,then edge flanges.

      When unfolded it ends up about .105" to short for forming.

      I should mention that I'm using .125" radius. If it was thinner

      material this wouldn't be a problem. The second way I tried

      extruding a blank to 1.0" ,shell it to .119" then rip the corners.

      Add sheetmetal and when this unfolds it's also comes up short.

      I'm using a .259 Bend allowance. Any thoughts on this for relief

      cuts. I tried tear,rectangle, and obround which you'll see that they

      don't work. I did try the 3rd way by creating a blank 6x6 converting

      to sheetmetal with the .119" thickness and what edge flanges with

      .010" gap. This when unfolded did come out correct but way to much

      relief for welding. Closed corner doesn't work. Any suggestions ???

      Still waiting from tech support.....

      Thanks

        • Re: RELIEF FORMING
          Charles Culp

          Emmett,

           

          On the top right of the page under the "Actions" tools you can edit this thread. I suggest putting this in the "Sheet metal" section not the "surfacing" section.

          • Re: RELIEF FORMING
            John Stoltzfus

            Good afternoon Emmett,

             

            Welcome to the Board.

             

            First I leave the bend allowance in the SW default.  The bending we do here is not high tolerance.

             

            The bend allowance is set at .50  and that could be part of your issue. 

             

            I did a sample model and came up with a 1.006 edge of flange to bend line dimension.

             

            I used the Sheet Metal Base Flange (6.0 x 6.0) then added Edge Flanges to the outside edges, check the correct box for material inside, outside, etc..

             

            Then use the Close Corner feature and your final bent pc should have very limited gaps, and you can control that feature,

             

            Later,

             

            John

            • Re: RELIEF FORMING
              Tom Smith

              At our shop, we use K-factor = .2733 and make the inner bend radius always the same as the thickness.  This way, a 1" flange bend line will be 1" from the edge on the flat pattern.  works every time.

              • Re: RELIEF FORMING
                Bernie Daraz

                Emmett, if you use a .259 bend allowance setting, I assume it is actually a bend deduction as shown in my attached picture. You should use a bend gap setting as shown to achieve a 1.014 (actually 1.015) dimension as you show.