Folded Box or Tray: flat pattern
A box, tray or pan folded from one blank: a base with four sides turned up, with or without a flange round the top. A box, tray or pan folded from one blank: a base with four sides turned up, with or without a flange turned outward round the top.
Open the folded box or tray in SheetMorphConfigurations
- Plain sides. A base with four sides folded up, open at the top.
- Flanged top. Each side carries a flange turned outward at the top, as a drip tray or a cover has.
A worked example
The plain sides configuration with the sizes SheetMorph opens with, in mm. One blank: the base, four sides, with 4 folds: 5 parts, 4 seams.
| Blank, the rectangle the plate is cut from | 802.0 mm × 602.0 mm |
| Length of cut, every outline and hole | 2808.0 mm |
| Bends (4) down, the pattern drawn outside face up | 90.0° |
| Length of the base | 601.00 mm |
| Width of the base | 401.00 mm |
| Height of the sides | 100.50 mm |
| Overall length | 802.00 mm |
| Overall width | 602.00 mm |
| Square cut out of each corner | 100.50 mm |
| Folds | 4 |
| P1 Base, long | 802.00 mm |
| P1 Base, wide | 602.00 mm |
| Plates | 1 |
| Triangular facets | 10 |
| Pattern extent X | 802.00 mm |
| Pattern extent Y | 602.00 mm |
| Developed area | 442,403 mm² |
| Total cut length | 2808.00 mm |
| Longitudinal seam length | 402.00 mm |
How it is developed
True-shape development of flat faces about the base. This is an exact development: the surface unfolds without stretching, so the pattern closes exactly.
- Every face is flat, so the blank is exact. It is the base with each side laid out from the edge it is folded on, which leaves a square to be cut out of each corner.
- The four upright corners are where two sides meet edge to edge: weld, solder or seal them, or add a seam allowance under Fabrication.
Checked before it can be exported
Every pattern SheetMorph draws is checked against the 3D part it comes from. For this example:
- Surface connectivity (passed): 10 facets form one open sheet: every edge inside a part joins exactly two facets, every open edge one (V - E + F = 1).
- Developed edges equal true 3D lengths (passed): 30 facet edges compared between the 3D surface and the flat pattern (max deviation 3.41e-13).
- Shared edges and seam closure (passed): 9 internal edges are shared vertex-for-vertex between adjacent facets; 4 seam(s) have mating edges of equal true length (max deviation 3.41e-13).
- Developed facets consistently oriented (passed): All developed facets are counter-clockwise (outside face up); none is mirrored or degenerate.
- Developed area equals surface area (passed): Facet area in 3D and in the flat pattern agree (difference 1.75e-10).
- Cut outlines closed and non-overlapping (passed): 1 closed outline(s); no outline crosses itself or another outline.
Assumptions
- The pattern is developed on the mid-thickness surface; inside or outside sizes are converted to it by the thickness.
- Curves are chains of chords between division points.
- No seam, lap, weld-preparation or pressing allowance is added.
Limits of this module
- Corners are plain square notches: no corner relief, tab, lap or seam is added, and the flanges are cut square, not mitred.
- Folds are sharp lines on the mid-thickness surface. Use the bend deduction under Fabrication for the inside radius and K-factor of the press brake.
- All four sides are of one height and stand square to the base; a sloping side is made with the pyramid hopper.
- No lid, hem, handle or drain is drawn.
- Curves are chains of straight chords between division points.
- No seam, lap, weld-preparation or pressing allowance is added, and plates are not nested onto stock sheets.
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.
Box. The box stands on its base at Z = 0, centred on the Z axis, its length along X and its width along Y. Corners are numbered 0 (-X, -Y), 1 (+X, -Y), 2 (+X, +Y), 3 (-X, +Y) seen from above; side 1 faces -Y, side 2 +X, side 3 +Y and side 4 -X. End A is the base and End B the top of the sides.
Blank. The blank is one plate with a square cut out of each corner, as large as the height of a side and the width of its flange together. It is drawn outside face up: the sides fold away from the reader. The four upright corners are joints between neighbouring sides.
Sizes and thickness. Length and width are across the opening and the height is from the base to the top of the sides, as inside, mid-thickness or outside sizes. The blank is developed on the mid-thickness surface: one thickness more or less in length and width, half a thickness in height. A flange is as wide as entered, measured from the side it is folded on.
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 folded box or trayOther folded work
- Straight Duct: A straight length of rectangular duct: one blank wrapped round to one seam, two L-shaped pieces, a U and a flat side, or four sides.
- Gutter Mitre: A box or half-round gutter cut on a mitre for an outside or an inside corner: the blank with its folds and the mitred end.