Cutting speed is the rate at which the head advances while the jet cuts the material. It becomes useful only when the material, thickness and required edge quality are stated alongside it. A feed rate on a long straight cut does not describe the time needed to finish a part with holes and corners.
Start with the edge you need
A separation cut and a finished edge answer different questions. The first asks whether the jet cuts through; the second also asks whether the surface and dimensions are acceptable. Increasing feed rate can make striations more apparent toward the bottom of the cut. Slowing the cut can improve the edge, but the required setting still depends on the material and cutting system.
State whether the part will be used as cut or machined afterward. For a fit-critical feature, specify the dimension and the surface on which it will be measured. That gives a cutting-time estimate a defined quality target.
Material, thickness and the cutting head belong in the estimate
Material identity and thickness are inputs to a cutting program, not interchangeable labels. Stone composition, for example, can affect the cut even when slabs have the same nominal thickness. The orifice, mixing tube and abrasive delivery also affect the cutting stream. A worn or poorly aligned cutting head can reduce its effectiveness.
Pressure is part of this setup. Record the working pressure used for the proposed cut, rather than treating the pump's peak rating as the cutting condition.
Follow the whole toolpath
Piercing, lead-ins, corners and travel between cuts belong in a part-time estimate. Ask for the time for the actual drawing, with its internal features, rather than multiplying an advertised straight-line speed by the outside perimeter. Loading, setup and inspection should be listed separately from the programmed cutting cycle.
For a repeat job, retain the drawing, material specification, thickness, edge requirement and machine configuration with the timing result. These are the conditions under which that result is useful for planning.
What to send for a cutting-time review
- The drawing and quantity.
- The material grade and thickness.
- Dimensions that need inspection and the desired edge finish.
- Any piercing, workholding or handling constraints.
Read about cutting cost factors and cutting thickness, or request a quote to discuss the job.