SolidWorks can automatically unfold sheet metal parts, including their fabrication, nesting, and bending processes.
Sometimes, the unfolded sheet metal created in SolidWorks may not match the actual unfolded sheet metal, resulting in inaccurate bending dimensions. What should you do in such cases?
The issue usually lies in incorrectly setting the bending parameters in SolidWorks.
Today, I will explain how to correctly set the bending parameters for sheet metal in SolidWorks.
There are several options for the bending parameters in SolidWorks, including Bend Allowance Table, K-Factor, Bend Allowance, Bend Deduction, and Bend Calculation.
Let's focus on the three simplest and most practical parameters.
SolidWorks Sheet Metal Bending Parameters:
1. Bend Deduction:
This parameter is the most commonly used when creating the bending features of sheet metal because it is simple and aligns with real-world scenarios.
The value of the Bend Deduction is equal to the actual Bend Allowance used, such as 1.7 times the sheet metal thickness or the Bend Allowance table provided by the sheet metal manufacturer.
Some sheet metal manufacturers subtract 0.8 times the sheet metal thickness from one edge. In this case, you need to multiply it by 2, resulting in a Bend Deduction of 1.6 times the sheet metal thickness. The Bend Deduction can be understood as the value subtracted from a right-angle bend.
Example of a 1mm Sheet Metal Bend Deduction:
For a 1mm sheet metal bend, the Bend Deduction should be set as 1.6mm.
2. K-Factor:
The Bend Deduction is commonly used for setting 90-degree bends in sheet metal. However, it is not suitable for bends with large radii or non-90-degree bends.
As mentioned earlier, the neutral layer in sheet metal bending with a large radius is half the sheet metal thickness.
In this case, the K-Factor can be set as 0.5.
Example of SolidWorks Sheet Metal Bending with Large Radius (K-Factor):
It is not recommended to set the K-Factor for large radius bends as a global parameter in the sheet metal feature since not all bends are large radius bends.
Instead, you can individually edit the bending parameters. For example, in the Edge-Flange1 feature, uncheck the box next to "Use default radius."
Change the bend radius to 20mm and select the checkbox next to "Use custom bend allowance." Set the K-Factor to 0.5.
After the automatic unfolding in the software, the result will match the manually calculated unfolding.
For non-90-degree sheet metal bends, it is also recommended to individually set the custom bend allowance.
For example, if the software sets the default bend allowance for sheet metal as 0.1mm, modifying the table data will automatically calculate a K-Factor of 0.2183.
Once you set the parameters in the software, it will automatically unfold the sheet metal.
3. Bend Allowance:
When designing sheet metal flanges, the calculated unfolding length may not be what we desire when using the Bend Deduction and K-Factor methods.
In such cases, we can use the Bend Allowance parameter. In the software, the Bend Allowance is calculated in the opposite way to the Bend Deduction.
Using Bend Allowance with Straight Edge and Bend Allowance Factor:
Sheet Metal Flange Setting:
If the sheet metal length on the drawing is 100, and the flange length is 10, with a default Bend Deduction of 1.6, a yellow warning will appear after unfolding.
The unfolded value will not be the desired 109.5. In this case, you can set the Bend Allowance as follows: 1 + 1 + 0.1 - 0.5 = 1.6.
Look, the unfolded length is now 109.5. How does the Bend Allowance of 1.6 work? 1 represents the sheet metal thickness, 0.1 is the software's default gap value (a fixed value), and 0.5 represents the Bend Allowance factor of the flange (the compression factor).
