Nesting for laser, plasma, waterjet and router

At a glance

Smallest-hole figures: plasma from Hypertherm's one-to-one rule; laser from SendCutSend's minimum-geometry guide; waterjet and router from SendCutSend's CNC routing and sheet guidelines. Every machine and material differs.

Laser

• The narrowest kerf of the four. Xometry's nesting guide uses gaps from about .03 in between laser parts.
• The heat is local, concentrated in a small area at the cut (Trumpf).
• Holes down to about half the material thickness are a common minimum (SendCutSend).

Plasma

• The widest kerf of the four, and it widens with amperage and thickness, so give parts more room than on a laser.
• Keep pierces off finished edges with lead-ins and lead-outs: Hypertherm calls the pierce the messiest part of the cut. Near a torch's maximum thickness, Hypertherm suggests a lead-in about as long as the plate is thick, so leave room for it in the nest.
• Hypertherm's rule for clean holes is a hole at least as wide as the plate is thick, cut slower than the outline.
• One side of a plasma cut is squarer than the other (the right side, in the torch's direction of travel), which is why the machine cuts outlines and holes in opposite directions.
• Thin aluminum moves as it heats; Hypertherm points to cut order, spreading the heat, and tabs.

Waterjet

• No heat and no heat-affected zone, so parts need no room for heat. The stream and holding the parts still need a gap: Xometry uses .125 in between waterjet parts.
• Waterjet suits common-line cutting, where two parts share one cut and save both material and time.
• Most abrasive waterjet cuts have some taper, slightly wider at one face than the other; cutting slower or a tilting head reduces it.
• Kerf follows the mixing tube's bore and grows as the tube wears.

CNC router

• The gap between parts has to be at least the bit's diameter, plus a little clearance, so the bit can pass between them.
• Inside corners come out rounded to the bit's radius; a 1/4 in bit leaves a 1/8 in radius.
• Small parts need holding down: tabs (thin bridges left uncut) or an onion skin (a paper-thin layer left at the bottom of the cut, about .020 in) keep them in place on a vacuum table that cannot grip them alone.
• Holes cannot be smaller than the bit.

Nesting all four in Nestor (opening soon)

Nestor is not open to everyone yet. When it opens, choosing the machine will set the part spacing to match, including the bit size for a router; it nests by the parts' true shapes across the full width of the sheet, so the drop is one clean piece, and gives a rough cut time for laser, plasma, waterjet and router. Sign up on the home page to hear when it opens.