AnsweredAssumed Answered

Bend Deductions are not correct

Question asked by 1-KXQ8ZY on Dec 28, 2009
Latest reply on Jan 2, 2010 by Kelvin Lamport

Ok, so I've had this problem for a long time, and have been using work a around to get the correct values.  However, I figure the time is now to post the question and see if I can get an answer.  Why do bend deductions in Solidworks not give you the proper flat length?  Bend deductions in theory relate to the amount of stretch on every corner.  A bend deduction is the amount of material you must subtract from the flat pattern in able to obtain your desired part.  Thus, if you put a bend deduction of 3/16" for every bend, then Solidworks should subtract that amount from every bend when constructing your flat pattern.  However this is not the case.  My flat patterns are always wrong compared to what it SHOULD be and I can't figure it out.  Now it would be acceptable to be off by a 1/16" or so but sometimes it is off by an inch which is totally unacceptable.  It appears that if the bend deduction is double the thickness of the material then I can obtain the correct flat pattern length.  However if I am bending 12 ga steel with a bend deduction of 3/16" I obtain totally wrong flat length dimensions.  This has me wondering how Solidworks actually uses Bend Deduction to calculate flat patterns.  It should be as simple as adding up all your bent dimensions and then subtracting the number of bends multiplied by the bend deduction to get a flat pattern.  I don't think I am doing anything wrong, but maybe I am.  My Solidworks VAR told me to try using decimals instead of fractions, which is a rubbish solution to a real problem.  Does anyone else have similar problems when creating sheet metal parts?  We bend all of our stuff in house so I need correct flat pattern lengths.  Please help me, I am desperate for an answer.


Thanks you.

Kevin Bartok