Metal Fabrication

Laser Cutting Throughput and Cost Per Part: Speed, Assist Gas, and Nesting

Laser cutting cost per part = machine time + assist gas + programming amortization + material handling. Here is how to calculate it and what thickness-to-speed tradeoffs look like.

Laser cutting cost per part = (cut length / cut speed) x machine rate + assist gas cost + nesting and programming amortization + load/unload labor. For a 1,200mm perimeter part cut at 4,000 mm/min in 3mm mild steel on a $120/hr fiber laser: cut time = 1,200/4,000 = 0.30 min = $0.60 machine cost. Assist gas (nitrogen for stainless, oxygen for mild steel): nitrogen at $0.18/min x 0.30 min = $0.054 (typical N2 consumption). Programming: $15 nest setup / 80 parts per nest = $0.19. Material handling: $0.25/part. Total: $1.09 per part.

Cut speed depends heavily on laser power, material type, and thickness. Mild steel cutting speeds on a 6kW fiber laser: 1mm = 16,000 mm/min, 3mm = 6,000 mm/min, 6mm = 3,000 mm/min, 12mm = 1,200 mm/min. Stainless steel: roughly 60-70% of mild steel speeds. Aluminum: 50-70% of mild steel (requires different cutting parameters). Cut speed roughly halves for every doubling of thickness above 3mm, meaning machine time per cut-length doubles. This is the dominant cost driver for thick plate.

Assist gas selection affects both cost and cut quality. Oxygen cutting of mild steel: fast, low gas pressure (0.5-2 bar), produces an oxidized edge (brownish), costs $0.05-$0.15/min in gas. Nitrogen cutting of mild steel and stainless: slower (10-30% speed reduction), high pressure (10-20 bar), produces a bright oxide-free edge, costs $0.10-$0.35/min in gas. Nitrogen cut edge requires no cleaning before painting or welding. Oxygen cut edge requires scale removal for weld quality and painting adhesion.

Nesting efficiency is as important as cut speed for part cost. A well-nested sheet at 78% material utilization versus a poor nest at 55% means 42% more material consumed per part in the poor nest. Material cost typically exceeds machine time cost on thicker gauges. Nesting software pays back within weeks to months of purchase for shops running more than 2-3 cuts per day.

Kerf width (cut slot width) affects part dimensions and material utilization. Fiber laser kerf in 3mm mild steel: 0.15-0.25mm. CO2 laser kerf: 0.2-0.4mm. Plasma: 1.5-4mm. Waterjet: 0.8-1.5mm. In tight nesting, kerf width adds to minimum part-to-part gap. Very tight nesting with small gaps risks thermal distortion from adjacent cuts. Leave at least 1x material thickness as gap between parts in most nesting applications.

Published 2026-05-28.