What is the real cutting speed of this portable waterjet on steel and concrete, and how does total job time compare to oxy-fuel or plasma?

The real cutting speed of a portable waterjet on steel and concrete depends primarily on material thickness and the abrasive flow rate. For mild steel, a typical portable system with a 30-40 HP pump and 60,000 PSI operating pressure can cut 6.35 mm (1/4-inch) plate at approximately 300 to 400 mm per minute. When the thickness increases to 25 mm (1 inch), the speed drops significantly to around 50 to 80 mm per minute. For 50 mm (2-inch) thick steel, the feed rate slows further to roughly 20 to 30 mm per minute. On concrete, the cutting speed is generally slower because concrete is highly abrasive and dense. A 50 mm thick concrete slab can be cut at about 40 to 60 mm per minute, while 100 mm thick concrete reduces the speed to approximately 10 to 15 mm per minute.

When comparing total job time to oxy-fuel or plasma cutting, the portable waterjet is considerably slower in pure traverse speed. Plasma cutting, for example, can cut 25 mm steel at speeds exceeding 1,500 mm per minute, which is roughly 20 to 30 times faster than a waterjet. Oxy-fuel cutting on 25 mm carbon steel operates at about 300 to 400 mm per minute, which is still several times faster than the waterjet's 50 to 80 mm per minute. However, total job time is not just about cutting speed. Plasma and oxy-fuel both produce significant heat, which creates a heat-affected zone that often requires secondary grinding or machining to clean the edge before the part is usable. This post-processing can add substantial time to the overall project.

The portable waterjet cuts with a cold, abrasive stream that leaves a smooth, burr-free edge with no metallurgical distortion. Parts come off the table ready for welding or assembly without any additional finishing work. This eliminates the time spent on deburring, grinding, or straightening warped materials. Additionally, setup time for a portable waterjet is often shorter because there is no need for grounding clamps, preheating, or gas bottle handling as required with plasma and oxy-fuel systems.

For a typical job cutting 25 mm steel plate, the plasma cutter might finish the cut in 2 minutes, but if the edge requires 5 minutes of grinding and the material warps and needs 5 minutes of straightening, the total process time approaches 12 minutes. The waterjet might take 15 minutes to cut the same piece, but with zero secondary work, the total job time is actually shorter. On concrete, oxy-fuel and plasma cannot cut at all, so the waterjet is the only viable portable option, making its slower speed irrelevant compared to the alternatives.

In summary, while the instantaneous cutting speed of a portable waterjet is lower than plasma or oxy-fuel on steel, the total job time is often competitive and sometimes faster due to the elimination of secondary operations, making it a practical choice for many field applications.