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Sheet metal flat pattern

Unfold an L, U, Z or hat sheet-metal bend into a flat pattern

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Sheet metal flat pattern with its default settings

Screenshot of the tool as it opens; it is a real capture, not a mockup.

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What is it?

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What it makes

A flat pattern for a single-axis, brake-formed sheet metal part: pick an L bracket, U channel, Z profile or hat channel, or build your own list of flanges, each with a bend angle and direction. Enter material thickness, inside bend radius, part width and whether flange lengths are measured to the outside corner or the inside corner (where the outer or inner faces would meet if extended through the bend), plus a K-factor from a material/method table or your own number. The tool computes bend allowance, setback and bend deduction for every bend using the standard air-bend formulas, draws the formed profile and the unfolded flat pattern with bend lines, and lists everything in a bend table. It exports a DXF (outline and bend lines on separate layers), an SVG for a laser or plotter (red cut outline, blue bend score), and a PDF shop drawing with the bend table and a 50 mm check square for verifying print scale.

How to use it

  1. Start from a quick start (L bracket, U channel, Z profile or hat channel) or build a flange list from scratch.
  2. Set material thickness, inside bend radius, part width and whether flange lengths are measured to the outside corner or the inside corner.
  3. Pick a K-factor method (mild steel, aluminum or stainless, air bend) or enter your own K-factor.
  4. Add, remove or edit flanges; each bend between two flanges has its own angle and direction.
  5. Check the Profile view for the formed shape and the Flat pattern view for the flat length, bend line positions and bend table, then download the DXF, SVG or PDF.

Build notes

  • Bend allowance (BA), outside setback (OSSB) and bend deduction (BD) follow the standard air-bend formulas from Machinery's Handbook and common K-factor references; K-factor table values are typical ranges, not a substitute for your own shop's bend tests.
  • Corner reliefs at flange intersections are not modelled; add them in your CAD package if the part needs them.
  • Works fully offline once opened; nothing is fetched.