Exact flat patterns for cones, transitions, elbows and branches

Pick a shape, enter its sizes and the sheet thickness, and download the flat pattern with numbered press lines as DXF for laser, plasma or waterjet cutting. A STEP of the part comes with it.

Unfoldo lays out the flat pattern (development) of common sheet metal and plate parts: cylinders, cones, transitions, segmented elbows, branches, breeches and flights. Enter the sizes, say whether they are inside, mean or outside sizes, and download the exact pattern with numbered press lines as DXF, with a STEP of the part for your CAD.

Most used shapes

Square to round: Rectangle to round transition
Truncated cone: Concentric reducer, frustum
Lobster back elbow: Segmented, mitred or gored bend
Pipe tee: Saddle cut and hole, 90° and lateral
Y-branch: Breeches, wye, pair of pants
Screw flight: Auger flight, helical ramp
Rectangle to rectangle: Duct reducer, hopper
Pipe to cone branch: A branch on a reducer or cone

All shapes

Cylinders & pipe cuts

Cylinder: Square ends, Angled top, Cut at both ends

Cones & reducers

Cone: Truncated, Full cone, By apex height, By cone angle, In levels
Cone cut by a plane: Top cut at an angle, Top and base cut at angles, Top cut by two planes, Base cut by two planes

Transitions

Rectangle to round: Centred, Square base, Offset, Angled top, Angled base, One angled side, Two angled sides, In levels
Rectangle to rectangle: Centred, Offset, Angled top, Angled top and base
Round to round: Angled top, Axis angled, Top at 90°
Oval to round: Centred, Offset
Oval to oval: Centred, Offset
Oval to rectangle: Centred, Offset
Ellipse to round: Centred, Offset, Angled top
Ellipse to ellipse: Centred, Offset, Angled top
Ellipse to rectangle: Centred, Offset, Angled top
Hexagon to round: Centred, Offset
Octagon to round: Centred, Offset

Segmented bends

Segmented bend, round: 90°, Any angle, Extended
Segmented bend, oval: 90°, Any angle, Extended
Segmented bend, oval on its side: 90°, Any angle, Extended
Segmented bend, tapered: 90°, Any angle

Elbows

Mitred elbow, pipe to pipe: 90°, Angled, Radius and angle, Double (offset), Double (offset), outside sizes, Double, offset two ways
Mitred elbow, pipe to cone: 90°, Angled
Mitred elbow, cone to cone: 90°, Angled
Mitred elbow, cone to pipe: 90°, Angled

Branches & tees

Pipe to pipe: 90°, branch, 90°, trunk, Angled, branch, Angled, trunk, Two branches, Two angled branches, Two branches along the trunk, Four branches
Pipe to cone: Level branch, cone, Level branch, branch, Upright branch, cone, Upright branch, branch, Angled branch, cone, Angled branch, branch
Pipe to oblique cone: Level branch, cone, Level branch, branch, Upright branch, cone, Upright branch, branch, Angled branch, cone, Angled branch, branch
Cone to cone: Level branch, trunk, Level branch, branch, Upright branch, trunk, Upright branch, branch, Angled branch, trunk, Angled branch, branch
Cone to oblique cone: Level branch, cone, Level branch, branch, Upright branch, cone, Upright branch, branch, Angled branch, cone, Angled branch, branch
Cone to pipe: 90°, branch, 90°, trunk, Angled, branch, Angled, trunk
Rectangle to pipe: 90°, branch, 90°, trunk, Angled, branch, Angled, trunk, Tangent, 90°, branch, Tangent, 90°, trunk, Tangent, angled, branch, Tangent, angled, trunk
Rectangle to cone: Level branch, cone, Level branch, branch, Upright branch, cone, Upright branch, branch, Angled branch, cone, Angled branch, branch
Rectangle to oblique cone: Level branch, cone, Level branch, branch, Upright branch, cone, Upright branch, branch, Angled branch, cone, Angled branch, branch
Pipe to bend: On centre, Offset, Angled

Breeches & Y-pieces

Round breeches: 3 pipes, 4 pipes, 5 pipes
Reducing breech: Angled tops, Level tops, With body, symmetrical, With body, equal ends, With body, unequal ends

Rectangular ducting

Straight duct
Duct reducer: Centred, One side straight, Offset, changing height
Duct offset: Same size, Same size, radiused
Duct branch: 90°, 90°, rounded corners, Angled, Angled, rounded corner
Duct Y: Symmetrical, 180°, Asymmetrical
Duct splitter
Duct elbow: Radiused, any angle, Mitred, any angle

Helicals & augers

Helical ramp: Triangulated, Angled flight, Tapered
Auger flight

How it works

Pick the shape: Search by the name your shop uses: square to round, reducer, lobster back, saddle, wye. Every shape shows its part in 3D.
Enter sizes and sheet: Type the sizes on the drawing, then set the thickness, whether sizes are inside, mean or outside, where the seams go and how many press lines.
Cut and form: Download the DXF for laser, plasma or waterjet, with numbered press lines, the weight and the cutting length. STEP too.

Why the patterns fit

Inside, mean or outside sizes

Sizes on the inside, the mean or the outside: the pattern is worked out on the mean surface, so the formed part meets its sizes.

Checked against reference parts

Every shape is compared point by point with reference parts before it opens, and each sheet is bent back onto its 3D model in our tests.

True curves

Arcs stay true arcs in the DXF and curves follow the part within 0.005 mm, so the cutting machine gets clean outlines.

Ready for the brake

Numbered press lines, the seam where you want it, the part in one, two or four pieces, and true lengths when you need them.

Questions

What is a flat pattern (development)?

The shape of the flat sheet that, rolled or pressed, becomes the part: a cone's pattern is a ring sector, a square to round's is a set of flat triangles and curved cone pieces. Unfoldo works it out from the sizes you enter.

Which files do I get?

A DXF of the pattern with the cut outline, press lines and labels on their own layers and a STEP of the part for your CAD.

How is the sheet thickness taken into account?

You say whether your sizes are inside, mean or outside sizes; the pattern is developed on the sheet's mean surface from them.

Do I need to install anything?

No. Unfoldo runs in the browser on any computer; your parts are saved to your account.

Plans