Guide to Mastering Sheet Metal Bending

Navigating from an initial idea to the end product in sheet metal bending involves a meticulous approach to both design and production. Here are the essential stages for effective bending:

  • Conceptualizing the Design
  • File Preparation
  • Executing the Bending
  • Completing the Finishing Touches

While numerous resources exist to aid in the bending process, this guide aims to outline the critical steps to ensure optimal outcomes with Gmetal.

Fundamental Concepts in Sheet Metal Bending

Before diving into the detailed guide, it’s crucial to familiarize yourself with some fundamental bending terminology. The following video covers all these terms comprehensively, setting the stage for you to craft a successful bent sheet metal product.

Step 1: Initial Design

We’ll explore basic design guidelines for bending. However, for detailed examples, our software tutorials are an invaluable resource.

  • Bend Deduction

A critical aspect of designing bent sheet metal is considering the bend deduction. This accounts for the material “stretching” during bending. Bend deduction varies with the material, its thickness, and the bend’s angle, essentially adjusting your part’s size to compensate for the material that stretches around the bend.

  • Flange Length

Understanding the required flange length, and whether it suits your chosen material, is essential. (The flange is the part’s edge bent up from the base.) For bending services with Gmetal, the flange length must be at minimum 0.500″ or four times the material thickness, whichever is larger, with specific materials and bend angles possibly necessitating longer minimum flange lengths. We provide a maximum flange length of 24”.

  • Bend Relief Notches

Incorporating bend relief notches in your design can mitigate bulging at your part’s corners and prevent tearing. These notches, either narrow slots or circles placed at corner points, should be at least half the thickness of your material in width, with a depth equaling the bend radius plus material thickness plus .020”. They reduce stress on the flanges’ inner radii, aiding in maintaining the integrity of the corners against the base material.

  • Spacing Features from the Die Line

Ensure all holes and features maintain a proper distance from the die line, with all cut-out elements being 0.255” to 1.150” away from the die line’s center. Each material and thickness has recommended distances for features relative to the die line; consult with our support team to confirm your design will not suffer from feature distortion.

Step 2: File Preparation for Bending

To ready a file for sheet metal bending, it’s essential to start with a flat layout. CAD software, such as Fusion 360, facilitates this with a dedicated sheet metal function. A flat layout is crucial as Gmetal requires 2D files for bending operations, though we also recommend including a 3D image of the part upon checkout for a clearer understanding of its intended assembly.

  • Bend Line Indicators

Ensure your file clearly marks bend lines with the appropriate indicators before submission for a quote. The preferred method for indicating bends varies with the design software utilized.

  • Pre-flight Checklist

Adhering to our comprehensive pre-flight checklist will ensure your file is primed for processing:

  1. File format compatibility (2D formats: .dxf, .dwg, .ai, .eps; 3D formats: .step or .stp)
  2. Holes and cutouts meet the minimum size requirement of 50% material thickness and are properly distanced from the die line
  3. Bend lines are accurately represented according to the design software used
  4. File is created to a 1:1 scale, with inches as the preferred unit of measurement
  5. All elements are unified in the same layer
  6. Removal of all unnecessary points, duplicate lines, empty objects, and text
  7. Closed contours for all shapes
  8. Shapes are fully united, combined, or merged
  9. Text converted to outlines or paths
  10. Reversed text (cut-out text) includes bridges or is stencilized

Following these guidelines ensures a seamless transition from design to the bending phase.

Step 3: Executing the Bending Process

The art of bending sheet metal enables the creation of numerous complex parts; however, there are certain limitations to the tooling capabilities. At present, we do not support the following types of bends:

  1. Acute angles beyond 130°
  2. Techniques such as curling, bump forming, or roll forming
  3. Coining processes
  4. Hemming operations

Step 4: Finishing Touches on Bent Sheet Metal

Post-bending, it’s common for parts to bear die marks. These are purely superficial and do not compromise the part’s functionality. Although no preemptive measures are offered to prevent these marks, they can be easily sanded away with a DA orbital sander upon receiving your parts. Furthermore, powder coating is an option for enhancing both the durability and appearance of bent sheet metal parts. It’s important to be aware that die marks might still be visible beneath the coating. While powder coating doesn’t mask all machining flaws, it does provide a layer of protection and finish to your components. For powder coating services, a custom quote will be necessary, and our support team is ready to assist in ensuring your powder-coated bent parts meet your exact requirements.

Streamlining the Sheet Metal Bending Process

At Gmetal, our aim is to simplify the bending process, ensuring it’s accessible and easy to grasp. We’re dedicated to expanding our resources to turn this vision into a tangible outcome. Explore our bending FAQs and don’t hesitate to contact our support team for any extra inquiries.

Once your design is complete and your file is prepped, use our instant quote tool to upload your project and initiate your tailored sheet metal bending project!

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