Cut-to-Length Accuracy — How to Read the Numbers

What Is Cut-to-Length Accuracy

Cut-to-length accuracy describes how closely the sheets from a coil cut to length machine match the size you ordered. The figures usually agreed are four: length tolerance, squareness (the difference between the two diagonals), flatness after levelling, and the condition of the cut edge. Unlike the strip-width tolerances of a slitting line, all four are measured on each finished sheet.

Cut to length production line

On a cut to length production line, accuracy is decided by three sections working together: the leveller, which takes out coil set so the sheet lies flat; the length measuring system, which tells the shear when to cut; and the shear itself, which decides squareness and the cut edge.

Cut-to-Length Accuracy — Method and Measured Values

Each figure is checked on finished sheet: length with a tape or a measuring bench, squareness by comparing the two diagonals, and flatness by laying the sheet on a flat table and measuring the largest gap. No fixed values are published for our coil cut to length line; the tolerances are agreed for your thickness, width, sheet length and steel grade before the order.

Steel cut to length line

A steel cut to length line for heavier gauges needs a stronger leveller and shear than one for thin sheet, and the tolerances it can hold change with them. That is why the figures are confirmed against your own coil range rather than read from a table; the line itself is described on the cut-to-length line page.

Sources and Standards Referenced in Our Records

Length, squareness and flatness tolerances for our cut-to-length line are agreed with you for each order, against your coil, your sheet size and any sheet standard your customer works to.

Step-by-Step Procedure

Getting accuracy figures for a steel coil cut to length line takes four steps:

1. Send the coil data: thickness, width, steel grade and coil weight.
2. Send the sheet data: length range, sheets per stack and what the sheets are for.
3. State the tolerances you need on length, squareness and flatness.
4. We confirm against your coil and sheet which tolerances apply, before the order.

Worked Example — What We Need From You

Length tolerance, squareness, flatness, cutting speed and output per shift all depend on the coil you run and the sheet you need, so for a coil cut to length line we work them out from your data: coil thickness, width and grade, sheet length, and the tolerance you need. For the difference between this line and a steel coil slitting line, see slitting vs cut-to-length; wholesale buyers can see our wholesale cut-to-length lines page.