Hello Fred,, I rarely use a flat pattern in a drawing but I have noticed that a lot of people on the forum do and I suppose if you are remotely (apart from the brake) programming it can come in handy. I found that no matter how many times I opened your drawing (no part open) I got the same thing. 0.2328 which seems like a low value for a k-factor. Question for you.. Is it always displayed as a k-factor in a drawing no matter if you select bd, ba, or bc in the property manager? Just curious since no matter what I used the result in the drawing always indicated K. How is someone supposed to know what that represents? I notice that you are using a version prior to 2014 which is the earliest version I have. Also curious as to what your Equations and annotations show in the part when the drawing is showing K0. See clip below. When was your version installed? The reason I ask is, if installed after after July 14, 2015 (or around), It might have something to do with a Microsoft update around that time. I would imagine that you updated your Cut-List and saved the part file after you fixed it.
thank you so much for your message. Great points.
yes I do work remotely 80% of my time and I use the bend line notes mainly for myself to see if the right BD or BA or K has been used.
The K0.2328mm is low but If I use this value in my jobs, I get very close tolerances.
I do BD test with 3 off-cuts like that:
I machine the faces on my mill CNC to have them SPOT ON and clean
with my press break guy we bend all 3 off-cuts
Each plate is measured before bending ( flat ) and after bending and difference between flat part ( before bending ) and folded sides ( after bending ) gives me the perfect BD.
I use an average value of those 3 tests....
Then I play with Solidworks model to get K-factor that gives me the same Flat Pattern length that is equal to the flat patter length with my BD.
I hope it make sense:-)
Photo below-example-old testing plates, 3 OFF, 4mm G250 steel, Bend R 6mm
I have got to say that all my K-factors for my work are nearly spot on.
I normally get +-0.5 mm over 10 bends ( if we use the same steel supplier with the same steel thickness )
I also know that people use K-factors like a rule of thumb which is very very inaccurate. I would never do that. I need to have my own BD,BA,K which reflects our Press Break machine and tooling.
the bend note by my default which I set in my bend note TXT file within SW setting is always set for BD and if I choose to display K or BA, I do change it manually in the Bend Note in the left tree on drawing page.
Yes I use SW 2013 SP0
I have tried to play and update the Cut-list, save the part, close and re-open everything but K0 has not been updated to the correct value:-(
I am starting to feel that my oldish 2013 SP0 version which has not been updated yet has some bugs.....
I suspect you are correct about the bugs... I have now thoroughly studied (I'm sure there is much more) flat patterns in drawings and their annotations etc. I found the .txt file you were talking about and the info in the Drawing View Manager. Thanks for the info. What you do to determine the bend deduction and resulting k-factor is certainly the way to go. I also suspect that the low value of k-factor (larger bend deduction) you are using is because of the larger than 1mm radius that results, which is common with thicker material and wide opening V dies. Of course if you tried to force a 1mm bend radius you probably would get some fracturing on the outside. This has been a good educational experience for me in regards to flat-pattern drawings. I thank you for that. Too bad I couldn't help solve your issue. Perhaps someone will come along with a solution.
Hi again Dennis,
Iit is very nice to know that my input can be helpful too.
I am very happy even thou the issue is still there. Well, not happy but happy:-)
And yes you are right about the K-factor with R larger than 1mm.
Lets see if someone else will come along to help me and anybody with the same issue......
3 years on and the K-factor bug is still ignored by SW!!!!!!