Is this flat pattern reliable? Has anyone tried similar case before?
Flat patterns can be very reliable but there are are lot of pieces of info that have to processed/added to get that reliability. The K-factor has to be selected correctly. That will be affected by various conditions - the type of equipment used to fabricate the part, the tonnage used for the forming, the physical characteristics of the material. If you are working closely with the company that is going to form the part, they should be able to provide you with that info. If you are making the parts in-house and don't have the info, you can use trial-and-error to achieve good results.
Sometimes it is best to allow the people doing the forming to do what they (hopefully) know best. If you provide them with the final, after-forming dimensions, they should be able to use their experience to figure the best way to achieve a flat pattern that will work for your part.
Yes, you are right. We build this in house. Previously, they used their own calculation and trial-and-error. Usually, i would compare their result with Solidworks and the difference is minor. At the end we just need to slightly adjust the parameter to achieve the part.
However, is this particular case, using previous method and compare with Solidworks, the part which been formed is out of spec-i should said the difference is too huge.
Therefore, i request help from here.
K-factor? Yes, i will take note of this.
Make sure that the resulting bend radius on the formed part matches what you specified in SolidWorks. Use radius gauges to check the outside of the bend (add the thickness to the radius you specified). We've found that usually the problem with stretchout is related to the 'actual' radius being different from the 'specified' radius. Double check the actual material thickness also, sometimes this is different from what you might have specified in SolidWorks.
I have measurre the actual thickness, which is 0.2MM less than my sketch.
I cut the flat pattern and press it. But the result is not correct. When we reached our desire pitch, the I/D is bigger than we required. So we further pressing until the ID reached our requirement, then the pitch is longer.
I tried to modified the K factor but nothing change to my flat pattern.
Check out this website. The pdf has a bunch of good information on metal forming. The BendWorks program is handy as well.
Thanks for your recommendation. I will try the program.
I had tried the program but it does not suit this case.
Thank you for your infor.
The K-factor does in fact work. Due to the fact that this part is not getting formed to terribly much, I increased the dimension tolerance and as you change the k-factor you will notice that it is changing. If you change the sheet-metal(1) k-factor perameter that is in the sub catagory of sheet-metal, with the overide default perameter checked, you will notice some dimension differences in my attached part/drawing file.
Are you using SW 2013? You said that you changed the K factor and there was no change to the flat pattern.
If that is the case, read this article: http://www.javelin-tech.com/blog/2013/04/alins-sw-2013-sp3-0-pick-of-the-day-total-control-for-the-bend-allowance-in-multibody-sheet-metal-parts/
In SW 2013 you can change the K factor at the body level or at the part level and have various controls in place that you have to consider.
Retrieving data ...