Flat-Oval Tee: flat pattern

A round or flat-oval branch on the flat side of a flat-oval main: the main with its hole, and the branch cut to the main. A round or flat-oval branch set square onto the flat side of a flat-oval main: the main unrolled with its hole marked, and the branch with its foot cut to the main.

Open the flat-oval tee in SheetMorph

Configurations

A worked example

The round branch configuration with the sizes SheetMorph opens with, in mm. 2 plates: the main with its hole, and the round branch: 2 parts, 3 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 P11944.1 mm × 1000.0 mm
Blank of P2787.3 mm × 200.0 mm
Length of cut, every outline and hole7862.7 mm
Sizes on the mid-thickness surface (used for the pattern)
Main, long way801.00 mm
Main, short way301.00 mm
Branch diameter251.00 mm
Tee
Main length1000.00 mm
End A to the axis of the branch500.00 mm
Branch length, from the flat side200.00 mm
Main
Width of each flat500.00 mm
Girth of the plate1945.62 mm
Branch
Girth of the plate788.54 mm
Hole in the main
End A to the near edge of the hole374.50 mm
Along the main251.00 mm
Plate blanks
P1 Main, long1944.10 mm
P1 Main, wide1000.00 mm
P2 Branch, long787.27 mm
P2 Branch, wide200.00 mm
Pattern
Plates2
Triangular facets136
Pattern extent X3217.40 mm
Pattern extent Y1000.00 mm
Area of the blanks2,101,556 mm²
Area cut out49,340 mm²
Net area2,052,216 mm²
Total cut length8650.73 mm
Longitudinal seam length1200.00 mm

How it is developed

Parallel-line development: the main unrolled, the branch unrolled with each line cut to where it meets the main. 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.

Main. The main runs along the Z axis from End A at Z = 0 to End B. Its long way, across the flats, is along X and its flat sides face +Y and -Y; each end is a half circle as wide as the main is across its round ends. The main is cut along the middle of its flat side on -Y.

Branch. The branch stands square on the flat side on +Y. Its position is measured from End A to its axis, and its length from that flat side to its open end, End C. A flat-oval branch has its long way along the main. Where the branch is wider than the flat of the main, its foot runs down onto the round ends, and is cut to them.

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 flat-oval tee

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