Forming

Sheet metal forming reshapes flat blanks into bends, rolls, and hems using controlled plastic deformation, enabling stiff, lightweight parts with repeatable geometry.

Overview

Sheet metal forming converts flat sheet into 3D geometry by bending, rolling, and hemming without removing material. Common operations include press brake bending for discrete angles, roll bending for large radii, and hemming to fold edges for safety, stiffness, or fit.

Use forming when you need lightweight parts with high stiffness-to-weight, clean external faces, and fast cycle times after tooling is set. It fits prototypes through production when bend lines are stable and features are accessible to standard tooling.

Tradeoffs: forming is sensitive to material temper, grain direction, and thickness; springback and bend allowance drive final dimensions. Tight hole-to-bend requirements can be difficult without added operations, and complex 3D shapes may require multiple hits, dedicated tooling, or alternative processes. Expect costs to concentrate in setup, fixtures, and iteration to dial in angles and repeatability.

Common Materials

  • Aluminum 5052
  • Aluminum 6061
  • Stainless Steel 304
  • Cold Rolled Steel
  • Galvanized Steel
  • Copper C110

Tolerances

±0.010" to ±0.020" (bend location/overall), bend angle ±0.5° to ±1° typical

Applications

  • Electronics enclosures and chassis
  • Equipment brackets and mounting plates
  • HVAC duct transitions and housings
  • Control panels and faceplates
  • Appliance panels and frames
  • Cable trays and covers

When to Choose Forming

Choose forming for parts primarily defined by bends, radii, and edge folds where strength comes from geometry rather than thickness. It works best when bend lines are consistent across revisions and quantities justify setup and first-article tuning. Favor designs that can be produced with standard press brake tooling and minimal secondary operations.

vs Cutting

Choose forming when the part needs 3D stiffness, flanges, or edge geometry that a flat profile can’t provide. Cutting is great for 2D blanks; forming turns those blanks into functional structures and improves rigidity without adding material.

vs Punching

Choose forming when bend geometry and part stiffness drive performance, and hole patterns are secondary. Punching efficiently creates holes and cutouts in flat sheet; forming is the step that creates depth, flanges, and hems that control fit and strength.

vs Fastening

Choose forming when you can replace separate brackets, spacers, or edge guards with integral flanges, tabs, or hems. Fastening is better for modularity and disassembly; forming reduces part count, hardware, and assembly time when geometry can be built into the sheet.

vs Welding (Sheet Metal)

Choose forming when a single formed part can replace a welded assembly and you want cleaner cosmetics, lower distortion risk, and more consistent dimensions. Welding is better when geometry can’t be unfolded into a blank or when you need closed sections and multi-part structures.

vs Hydroforming

Choose forming for straightforward bends and large-radius rolls that fit common tooling and need shorter lead times. Hydroforming makes deeper, more complex 3D shapes with smoother strain distribution, but typically needs specialized tooling and higher setup cost.

Design Considerations

  • Follow minimum inside bend radius guidelines for the material and thickness (often ≥1xT for mild steel/5052; larger for 6061 and stainless).
  • Provide adequate flange length for tooling and gauging; short flanges drive special punches, added hits, or manual methods.
  • Keep holes, slots, and emboss features away from bend lines; use a setback at least 2–3x thickness plus bend radius when possible.
  • Specify grain direction if crack risk matters; place critical bends across grain for tighter radii on crack-prone materials.
  • Call out which dimensions are critical after forming and use bend angle/leg length tolerances that match function, not blanket tight tolerances.
  • Avoid stacked bend tolerances by dimensioning to a consistent datum scheme and providing a flat pattern (or stating shop-developed flat is acceptable).