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Sheet metal CAD online: flanges, bends, flat patterns

The SHEET METAL tab is for parts bent from one sheet: enclosures, trays, brackets. You start with a flat plate and bend walls up from its edges (the program calls them flanges). At the end the part unfolds flat into the shape you cut from the sheet. It runs in the browser, with no install and no account.

What you can do

  • Sheet Metal Rule holds the project settings: thickness, bend radius (the rounding inside a bend), miter gap and K factor. They prefill the sheet metal tools and are saved with the project.
  • Base Flange turns a closed sketch area into a plate by opening Extrude with the rule's thickness.
  • Flange bends a wall up from one or more straight edges. Type the length and angle (5 to 180 degrees) or drag the arrow and arc on the preview. Bend position is Adjacent, Outside or Inside, which keeps the outer face of the wall in line with the edge, so the outer size of the part stays the same. Extent set to Offset from ends shortens the wall at both ends, and Bend relief then notches the plate so the bend does not tear the sheet beside it.
  • Corners where two walls of one flange meet: Mitered, Overlap (the longer wall covers the end of the shorter one) or Open, with a Gap. Corner relief cuts a small round or square hole so the two bends do not overlap in the flat pattern.
  • Hem folds the edge back by 180 degrees, for example so it is not sharp.
  • Bend folds a plate along a straight line sketched on it, with an angle, a radius and the line at the start, center or end of the bend.
  • Contour Flange builds sheet metal from a chain of sketch lines, such as a channel or a Z bracket. Every corner gets a bend, and a fillet drawn in the sketch keeps its radius.
  • Extrude with a cut makes windows in the walls; Hole, Fillet and Chamfer are there too.
  • Create Flat Pattern places a flat plate with bend lines next to the model, and it updates with the model. Or ask for a one-off sketch: the cutting outline plus bend lines as construction geometry.
  • Unfold flattens the sheet in place so you can cut across a bend, and Refold bends it back, wrapping the cut around the bend.

The K factor marks the layer inside the sheet that neither stretches nor compresses when bent: 0 is the inside of the bend, 1 the outside, 0.44 by default. It sets the length of the flat pattern. Every operation stays on the timeline, and a double-click reopens it.

How it works in practice

A 160 × 100 mm tray with 25 mm sides:

  1. Click Sheet Metal Rule and check the thickness and bend radius (2 mm each to start with).
  2. Sketch a 160 × 100 mm rectangle, click Base Flange and confirm. You have a flat plate.
  3. Click Flange and pick the four edges of the top face. Type 25 mm or drag the arrow. A 90 degree angle, Mitered corners and a round corner relief are already set.
  4. Click Create Flat Pattern, pick the bottom of the tray as the face that stays in place and confirm with Flat pattern body. A flat plate appears next to the tray.
  5. On the DRAWING tab, add a Base view of the plate. Bends get notes such as "UP 90° R2", and Bend table lists their direction, angle and radius (see technical drawings).

For a cutter, make the flat pattern as a sketch and use Save as DXF from its menu in the tree; Include construction geometry adds the bend lines on their own layer. Nest arranges several plates on a sheet (see file formats).

Things to keep in mind

  • Flanges go on straight edges only. On an arc the program refuses and says why: the wall would stretch the sheet and could not be unfolded.
  • Pick edges of the large flat face. An edge along the plate's thickness is rejected.
  • Flange, Hem and Bend read the thickness from the body, so they also work on an extruded or imported plate. The flat pattern follows rounded bends only; anything past a sharp corner is left out.
  • The rule prefills new operations. Existing ones keep their values: adjust them with a double-click on the timeline.
  • Flange, Hem, Bend, Contour Flange, Create Flat Pattern, Unfold, Refold and Nest run on the server and are grayed out without a connection. Base Flange and Sheet Metal Rule work offline.