AnsweredAssumed Answered

Joggle or Offset Bend Allowance? (new post, still trying!)

Question asked by Bernie Daraz on Sep 20, 2011
Latest reply on Sep 21, 2011 by Bernie Daraz

I had an earlier post in this regard, to me there is no way to 'tell' SW your tried and true bend allowance for a joggle or offset bend. When I mention tried and true, it has been actually tested in the same material, grain direction, width or length of bend and tooling. In my case I have a list of them that has been built over 37 years in this business, for both bend allowances and bend deductions.


So now I'm doing the design and I want to provide models that flatten and can be imported into the vendors systems without tedious programming and modifications. This joggle allowance in SW is totally messed up and virtually incorrect. Today I was working on a part with a simple joggle and I look at my list, it should have a bend allowance of .010 for a .040 offset in .036 steel. No way can I enter that directly! I could layout this part using scribe lines faster!


Then it occurs to me that using "fix projected length" and allow me to enter a known allowance there and I'm done. But it doesn't work that way! Anyone in this business for a decent amount of time knows that a joggle shortens the blank. We're not concerned about the height of the joggle (so much) as that is controlled by the depth of penetration of the tooling. We are only concerned with the amount the blank shortens, that is the joggle allowance.


A k-factor cannot be used because it is not consistant even in the same material. A k-factor would be one number for a joggle that is 1/16" deep and then a totally different number for it if the joggle depth was 3/32". We do send out parts that have two joggles in the middle area and mounting holes on the ends that need to be within .010 after bending.


Think about it, if your comment is that it's close enough for us, it most likely wouldn't be if you were paying the professionals to do it. If your prints had decent tolerences on them you would be able to reject the parts. If your vendors are asking for fully dimensioned prints, your SW files are doing them no good. OK, they do use that excuse to get a few more delivery days too if they're running late or have already messed up your parts once.


My two cents worth of venting! I see it hasn't been fixed in 2012 beta, so far.


I would love to hear from someone who has a repeatable and accurate method. (play the theme from Mission:Impossible here! LOL!)