Sheet and Plate Cutting Optimizer

What does the sheet cutting optimizer do?

It nests a list of rectangular parts on your sheet or plate sizes and reports how many sheets are needed, the utilisation ratio, the waste and the large rectangular offcuts that remain. A scaled layout drawing is produced for each sheet. Sheets cut with the same layout are grouped in one drawing with a sheet count. You can download the result as CSV, the drawing as SVG, or print it as a cutting sheet.

Guillotine cutting or free layout?

Guillotine shears, circular saws and panel saws cut from edge to edge. On these machines every cut has to split the piece in two. The guillotine option only produces layouts that can be cut this way. Laser, plasma, oxy fuel and waterjet tables have no such restriction. The free layout option is meant for them and usually packs a little tighter.

How are the allowances handled?

Kerf is the smallest gap left between two parts: blade thickness, or laser and plasma cut width plus a safety allowance. Edge margin is the strip kept clear along all four edges of the sheet. Parts may touch the sheet edge or the margin line.

An example

Four 500 × 500 mm parts fill a 1000 × 1000 mm sheet exactly when the kerf is zero, with no waste. With a 2 mm kerf the total is 500 + 2 + 500 = 1002 mm, two parts no longer fit side by side and four sheets are needed. You would have to make the part 499 mm or move to a larger sheet size.

Lower bound

The tool shows a lower bound: the sum of part areas including kerf divided by the sheet area, rounded up. No layout can use fewer sheets than this. Because of the shapes of the parts, the true minimum may be higher than this bound. For that reason the tool never calls its layout optimal, it only tells you how close it is to the lower bound.

Method and limits

• Three heuristics are tried: shelf packing, guillotine splitting and maximal free rectangles (MaxRects). Each runs with several sort orders and the layout using the least sheet area is kept.
• Only rectangular parts are nested. For curved or polygonal parts enter the bounding rectangle.
• Parts are rotated by 90 degrees only. If grain or pattern direction matters, switch off rotation for that part.
• In guillotine mode the cutting sequence and the number of cutting stages are not limited.
• Offcut sizes are net sizes, with edge margin and kerf already deducted.