What a waterjet cut costs
Waterjet cuts anything with no heat-affected zone, but it is slow and it eats garnet. The two costs that dominate are the time on the machine and the abrasive flowing through the nozzle. This calculator tracks both, plus pump and water, and tells you how many pounds of garnet a job will consume so you can stock it and price it.
How it adds up
Cut time is length over speed plus the pierces, which on a waterjet are slow. Garnet used is the abrasive flow in pounds per minute times the cut minutes, and abrasive cost is that weight times the garnet price. Labor and pump costs are billed per hour of cutting. Add them for the total.
Garnet is the lever you control
Abrasive flow sets both cost and cut quality. Turning it down saves garnet but slows the cut, which adds machine time — so the cheapest setting is rarely the lowest flow. The weight figure here lets you see the trade directly.
Related tools
For the time alone, use the cutting time calculator. Compare against thermal processes with the plasma cutting calculator and laser cutting calculator.
Worked example
Sixty inches at 5 IPM with two slow pierces, $90/hr labor, $15/hr pump and water, 0.75 lb/min of garnet at $0.35/lb: the cut runs about 12.3 min, uses about 9.2 lb of garnet for roughly $3.22, labor about $18.40, pump about $3.07 — near $24.70 for the cut.
FAQ
Why is waterjet so much dearer per foot?
Speed. At a few inches per minute the machine time per part is large, so even with cheap garnet the labor and pump hours dominate. Waterjet wins where heat or thickness rules out plasma and laser, not on price.
Does abrasive recycle?
Some shops reclaim garnet, which lowers the abrasive line. If you recycle, enter your effective net garnet price rather than the new-bag price.