Rectangular Branch on a Round Pipe: flat pattern

A rectangular branch set square onto a round run, on its centre or offset: the run with its hole, and the branch folded at its corners. A rectangular branch set square onto a round run, on its centre or offset to one side: the run unrolled with the hole marked, and the branch in one plate folded at its corners with its saddle cut.

Open the rectangular branch on a round pipe in SheetMorph

Configurations

A worked example

The on the centre configuration with the sizes SheetMorph opens with, in mm. Two plates: the run with the hole for the branch, and the branch folded at three corners: 2 parts, 4 seams.

The flat pattern of this example: outlines to cut, with the lines to mark and any holes. Open it in SheetMorph for the dimensioned drawing and the files to cut it.
For the shop
Blank of P11571.4 mm × 1200.0 mm
Blank of P21104.0 mm × 383.2 mm
Length of cut, every outline and hole8540.9 mm
Sizes on the mid-thickness surface (used for the pattern)
Diameter of the run501.00 mm
Width of the branch301.00 mm
Depth of the branch251.00 mm
Run
Length1200.00 mm
Girth of the plate1573.94 mm
Hole in the run
Length along the run301.00 mm
Width round the run, laid flat262.90 mm
Seam to the middle of the hole, round the run786.97 mm
Branch
Girth of the plate1104.00 mm
Shortest line, where the saddle is highest349.50 mm
Longest line, at a side383.21 mm
Length of the side on -Y383.21 mm
Length of the side on +Y383.21 mm
Rise of the saddle33.71 mm
Plate blanks
P1 Run, long1571.41 mm
P1 Run, wide1200.00 mm
P2 Branch, long1104.00 mm
P2 Branch, wide383.21 mm
Pattern
Plates2
Triangular facets132
Pattern extent X3068.26 mm
Pattern extent Y1200.00 mm
Area of the blanks2,297,358 mm²
Area cut out79,006 mm²
Net area2,218,352 mm²
Total cut length9667.90 mm
Longitudinal seam length1583.21 mm

How it is developed

Parallel-line development (unrolled run, branch of flat sides). This is a triangulated approximation: the curved surface is divided into small flat triangles, each laid out at its true size. The finer the division, the closer the pattern is to the surface; SheetMorph states the deviation it found.

Checked before it can be exported

Every pattern SheetMorph draws is checked against the 3D part it comes from. For this example:

Assumptions

Limits of this module

Conventions

Coordinate system. The part stands on the Z axis with End A at Z = 0. Angles round the axis are measured from +X toward +Y, counter-clockwise seen from +Z.

Divisions and thickness. A circle is divided into 4N equal chords. Sizes are inside, mid-thickness or outside sizes; the pattern is developed on the mid-thickness surface and the views show the sizes as entered.

Run. The run stands on the Z axis from End A at Z = 0 to End B. It is cut along the line opposite the branch, on the -X side, so the hole is in the middle of its plate.

Branch. The branch leaves toward +X, square to the run, and ends at End C. Its width is along the run and its depth across it; its position is measured from End A to its axis, and its length from the axis of the run to its end. Offset, its axis is moved along Y, positive toward +Y.

Saddle. The two sides of the branch that face the ends of the run are flat and meet the run in arcs; the two that run along it meet it in straight lines, at the height of the run under them. The branch is one plate, cut at its corner toward End A on the -Y side and folded at the other three.

Hole. Laid flat with the run, the hole is a true rectangle: as long along the run as the branch is wide, and as wide as the arc of the run between the two sides of the branch, which is more than the depth of the branch.

Change the sizes to your own in SheetMorph, check the drawing, add seam and flange allowances, and export DXF, PDF, SVG, CSV or G-code. Check every pattern against your own standards before cutting.

Open the rectangular branch on a round pipe

Other intersections