Designing for Online Sheet Metal Bending Services

Table of Contents

In this tutorial we’ll cover all the basics for designing your files with bends.

Before you Begin

We realize everyone has a different level of knowledge and experience. We’re here to help you at every stage of the process. If you’ve never sent us a file before, or are unfamiliar with metal bending, we have a few guides you may want to check out before proceeding:

SendCutSend Design Guildelines
Metal Forming and Bending Guidelines
Designing for Laser Cutting in Illustrator

File Format

Prepare and Upload your Design File for Order Custom Metal Parts Online 1

Please upload a flat vector file such as .DXF, .AI or .EPS as you normally would. Make sure the file you upload for bending is a flat, 2D file. You will be able to view your bends in a 3D model during the checkout process to make sure the angles and flange orientations are correct.

If you design your parts in non-CAD software (Adobe Illustrator), please send us the original (native) ai file. We’ll take care of the conversion on our end. While we accept .AI and .EPS files, it’s critical that your bend lines are parallel when uploaded from these softwares or the file will delay our process.

For the fastest turnaround on your order, we recommend designing your parts in a CAD software, such as Fusion360, AutoCAD, or SolidWorks.

There are a two main things to note when designing for bending: bend lines and bend deductions. We’ll cover both of these points and more.

Bend Lines

First you need to decide where your bend (or bends) will be on your part. Some things to keep in mind are the minimum and maximum flange length. The flange length must be at least 1/2″ (.500″) or 4x the material thickness, whichever is greater. The maximum flange length is 22″. Some materials will require different flange lengths based on the material type and thickness, so be sure to reference our bending max/min chart to know exactly what your project can handle.

Once you’ve planned your bends, you will need to indicate where on your part you want the bend(s) to occur. We refer to these as the bend lines. On your flat file, you will indicate these lines differently depending on what file you are using. The following table explains exactly what indication we need from your software:

Fusion360.dxfSolid line (default)
Adobe Illustrator.aiSolid, separate color from cut lines
SolidWorks.dxfDashed line (default)
AutoCAD.dxfDashed line
CorelDraw.epsSolid, separate color from cut lines
Inkscape.epsSolid, separate color from cut lines

Bend Deduction

The next thing to consider is bend deduction. Bend Deduction is used to counteract material stretch caused by forming. This is unique to each material type, thickness, and bend angle. Don’t worry, we’ve created a calculator to help you make your measurements spot on.

Advanced-user note: All calculations should be for air bending not coining.

Once you have your new measurements from the bend calculator, you’ll want to adjust your design file accordingly. You will be reducing the length of your base and flange to accommodate the length of the bend itself. See the illustration below for an example. The green line indicates where the bends will occur. Keep cut out areas and holes away from these lines to avoid distortion.

Bend Angles

When designing and calling out your bend angles, it is important to note that the angles are measured on the outside of the bend. See the example below. The acute bend is measured as 130°, and the obtuse bend as 45°.

3D Rendering or Profiles

In addition to your flat vector file, we recommend sending a 3D rendering or a side view profile to help us understand how you are expecting your bends.

If you don’t have access to 3D rendering software such as SolidWorks or Fusion 360, you can always send us a sketch or profile view of your drawing in Illustrator. If all else fails, send us a screenshot of the side view from our Bending Calculator.

Exporting your design

We’ve set everything up on our end to make uploading as painless as possible. When designing in Illustrator, please send us your files in .ai format.

As always, before you upload your file, go through the usual checklist to make sure your file is ready to be cut.

Check out our processing page for information about typical lead times for parts with bending and other services. We provide free 3-5 day shipping for standard orders (higher quantities may require additional time). Most bent parts will ship ground as they will exceed 2″ in height when packed.

Preflight Checklist

Before you upload your design files, be sure to go through our pre-flight checklist:

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We proudly use hardware by PEM

Flush Standoff, 4-40, .250" Zinc plus Clear Chromate

Aluminum: 5052, 6061, 7075 Steel: Mild, G30

Thread Size4-40 x .250″
Hole size in sheet (+0.003/-.0.000).168″
Minimum sheet thickness0.040″
Maximum sheet thickness.125″
Fastener materialSteel
Minimum distance hole C/L to edge0.230″
When determining the distance between two or more fasteners, you can calculate the distance by the formula, C/L to edge + 1/2 the diameter of the second mounting hole..345″
Recommended panel materialSteel/Aluminum
Coating typeZinc
Aluminum material ranges (5052, 6061, 7075)0.040″-0.125″
Steel material ranges (CRS, HRPO, HR)0.048″-0.119″

We proudly use hardware by PEM

Flush Standoff, 4-40, .250" Passivated

Stainless Steel: 304, 316

Thread Size440
Hole size in sheet (+0.003/-.0.000).166″
Minimum sheet thickness0.04″
Maximum sheet thickness.125″
Fastener material400 Stainless Steel
Minimum distance hole C/L to edge0.230″
When determining the distance between two or more fasteners, you can calculate the distance by the formula, C/L to edge + 1/2 the diameter of the second mounting hole. Example shown with x2 of the same hardware..345″
Recommended panel materialStainless Steel
Coating typePassivated
304 Stainless Steel material ranges0.048″-0.125″
316 Stainless Steel material ranges0.060″-0.125″