In the bend_calculation.xls, does anyone know what the "lg" represents in the k-factor equation?
In the bend_calculation.xls, does anyone know what the "lg" represents in the k-factor equation?
This isn't a direct answer to your question, but attached is information I put together to explain K-factors and a spreadsheet to facilitate data collection for calculating your own.
Thank you Dennis.
I did see your attachments on two other posts.
My sheet metal shop uses bend deduction. They have not shared a full table. And when i'm bedding at various angles, without the K factor or deduction values, I don't want to have to add a line every time I use another angle. I've had better luck with the calculation table. At least to quickly complete mockups. Then the shop adds the info they need when I give it to them.
My question is to better understand what Solidworks is actually doing in that file.
Hello,
I believe it's supposed to be "log".
As you deviate from the theoretical inside radius = sheet thickness (log(1) = 0), it adjusts the 0.65 value by 1/2 of the log ratio.
Cheers,
Kevin
EDIT: Here's the equation graphed:
Hi Derek,
That's a bend table as per DIN 6935 - Cold bending of flat rolled steel.
The formula is correct. "lg" stands for log(10).
L = a + b + v
Elmar
Thank you both Kevin Chandler and Elmar Klammer.
I think you're both right. Elmar, thank you for clarifying the source.
Now, looking at DIN6935, I want to list all the variables in case someone else has a similar question for other variables in this sheet. They are not all defined in SolidWorks bend_calculation.xls, and there are a couple conflicting variables representing the greek notation.
DIN 6935:2011-10
α = Bending angle (DIN6935)
ß = Opening angle (DIN6935)
b = Leg length (DIN6935)
b = ß (Solidworks "bend_calculation.xls")
a = Leg length (DIN6935)
a = α (Solidworks "bend_calculation.xls")
Bend Angle = ß = 180-α (Solidworks "bend_calculation.xls")
v = Compensating value (DIN6935 & Solidworks "bend_calculation.xls")
Developed length = a + b + v (DIN6935)
k = Correction Factor or k-factor (DIN6935 & Solidworks "bend_calculation.xls")
Hi Derek,
I don't know of any other standard like this for Alu or or other steels. It's fairly old and was re-issued in 2011 with minor cosmetic updates.
That's a official standard and you are technically not supposed to copy sections out. But I think showing the sketch is okay.
The leg measurements change depending on the bend angle range (use tangent length setting)
The formula works best only between r/s of 0.8...5
For r/s > 5 you use a correction factor k of 1
For r/s 0.25 ... 0.8 you can use the formula with some restrictions as seen from graph below.
For r/s <0.2 you use a correction factor of 1
Elmar Klammer, do you know of an aluminum version of that standard? Or any other material for that matter?
Hi Derek,
That's a bend table as per DIN 6935 - Cold bending of flat rolled steel.
The formula is correct. "lg" stands for log(10).
L = a + b + v
Elmar