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Sheet Metal Bending Calculator

Use SendCutSend’s bending calculator to input your desired material and the units of measurement for your design to get the calculated bend allowance and bend deduction for your part before sending it to our lasers. The calculator also allows you to input flanges. Watch the video below for a detailed guide on how to use the bending calculator.

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Using the Bending Calculator

We’ve put together this guide to help you learn how to use our Bending Calculator for your CNC bent sheet metal parts. Follow the steps below and implement the results in your own file for the best results.

Step 1: Select material type, thickness, and desired units

Step 2: Select your view

The default option is a top view of the part you are gathering data for. You can select the side view to get an idea of what it will look like after bending

Step 3: Enter your base length

This represents the overall outside desired dimension of the base, center, or largest section of the part. If this was a U-channel, this would be the outside dimension after bending of the center section.

Step 4: Enter your flange dimensions

These are also entered at the desired outside dimension after bending. You can adjust the flanges to be on either side of the base by selecting the left or right position.

This will result in the Top view showing the location the bend lines need to be placed in the flat pattern with the bend deduction taken into consideration.

Step 5: Adjust your design

You can then adjust your design to match the overall outside dimension (17.765”) and add the bend lines (3.903”) from the edge of the part. Once this is bent, it will have the desired outside flanges (4” outside dimension) and base (10” outside dimension).

If you’re utilizing 3D CAD software, draw the part with the flanges in place using the sheet metal function in whatever CAD software you are using. Once you have the flanges in place, edit the bend radius to match the advanced details found at the bottom of the bending calculator. Once the radius is updated, adjust the K-factor or Bend deduction value to match that in the advanced details. To verify the part is correct you can flatten then measure the overall length, and bend line locations in reference to the bend calculator layout.

Keep in mind if you need a specific inside dimension you will need to add some clearance (at least 0.030”) and adjust based on the material thickness. For example, this part will have an inside dimension of about 9.762”

For this example, using 0.119” Mild Steel and bending at 90°, we will have a bend deduction value of 0.194” for each bend which is where we get the total length of 17.612. You can find the bend deduction value at the bottom of this page in the “Advanced Details.” If you want to learn more about calculating bend deduction, check out our Guide to Calculating Bend Allowance and Bend Deduction.

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