Laser or waterjet?

Comparisons of power of thickness and cutting quality

Fiber laser:

500W stainless 1mm, black 3mm, aluminum 1mm
1000W stainless 2mm, black 6mm, aluminum 2mm
2000W stainless 6mm, black 12mm, aluminum 6mm
3000W stainless 8mm, black 15mm, aluminum 8mm
4000W stainless 10mm, black 20mm, aluminum 10mm

These are the maximum real thicknesses for a given power.
Quality cutting applies to the given thicknesses reduced by about 20%. The
thicknesses given by the source manufacturer are about 20% higher, but are obtained with very critical parameters and rather theoretical values ​​obtained in laboratories.

Waterjet allows you to cut virtually all materials up to about 200mm thick.

Depending on the thickness and material, the cutting quality will be better laser or waterjet:

Steel: up to 2mm laser, above waterjet
Stainless steel: up to 2mm laser, above waterjet
Aluminum: up to 1mm laser, above waterjet
Copper, brass: up to 0.5mm laser, above waterjet

Black steel is laser cut cleanly and without hail. Up to 8mm thick, the cut is smooth and shiny. Above, the surface becomes more and more dotted with vertical lines.
Stainless steel is laser cut cleanly and without hail to about 3mm above, a small hail appears and increases with increasing thickness.
The aluminum is cut with a very small hail of up to 2 mm above the hail, which increases with increasing thickness.
Copper only thin sheets with little hail.

All metals below 3mm thick are cut with light hail, above this thickness the hail disappears.
The feed speed determines the quality of the cut. The slower the feed, the better the edge quality.
Waterjet cuts any material.

Speeds: A
laser is faster than a waterjet.
The thicker the sheet metal, the laser advantage decreases.
With a 3mm sheet, the laser is faster 5-10 times, and with a 10mm sheet 3-5 times.
Above this thickness, in order to maintain a quality comparable to a waterjet, it is necessary to cut in the pulse mode, which makes the speeds comparable.
If we do not care about quality, the laser can still cut faster than a waterjet.

Technical costs of cutting with abrasive on waterjet are about PLN 50 / h
Technical costs of cutting on a fiber laser, depending on the type of gas and whether we use liquefied gas or not, is about 30-50 PLN / h.

Summing up:
Thin black and stainless sheets are much better to cut with the laser because the cost of cutting the detail due to the efficiency is many times lower than on a waterjet.
Above 5mm stainless steel, copper and 1mm brass and 10mm black sheet metal, with increasing thickness, it is technologically better to cut with a waterjet.
If versatility is your priority, you should choose a waterjet, if you want to cut thin sheets efficiently, a laser will be better.
Unfortunately, often versatility and performance are equally important.
Then it is ideal to have a waterjet and laser.
Often, when thinking about buying a high-power laser, you can consider reducing the power of the source and buying a waterjet for the money saved.
For the price of a 4kW laser, you can approximately buy a 2kW laser and a waterjet cutter, which will increase the possibility of cutting from 20mm to 200mm without losing the advantage when cutting thin sheets.