Cutting speed is determined by many factors. Some of these are built into the machine, so you have no choice about, and some of them you have control over.
- How much power is at the nozzle - You cannot adjust this
- The abrasive size, quality, and flow rate - Something you typically should not adjust on the ProtoMAX
- The thickness of your material to cut - Thicker is slower
- The material to cut - Some materials cut at significantly different speeds than others
- The geometry of your path - tight complex corners are slow
- How good of (or the "Quality" of) the cut you desire (surface finish / tolerance)
- The length of your lead ins and out (where you pierce)
Below I will go into some detail on the above items that you have control over:
The thickness of the material to cut
Thicker is slower to cut. The thicker you go, the slower it goes, as an exponential function. So something twice as thick may take 3 or 4 times the amount of time to cut. Since your design requirements for your project may require a certain thickness, it's not always practical to change that. However, in some cases you can cut faster by cutting several thin parts and then stacking them to make the final thick part. So, not a lot you can do here, but at least something.
The material to cut
Again, your design decisions may dictate the material you are going to cut, but if you have the choice, choose materials easier to cut. Aluminum cuts at about twice the speed as steel, for example.
The geometry of the path
Here you have a lot of room to improve cutting speeds. Sharp corners cut slower than corners with radii, or corners that are not so sharp of an angle. The sharper the corner, or the tighter the radius, the slower it will cut. This is very significant, especially in thicker materials, because the jet must slow down in order to make a precise corner. To maximize speed avoid unnecessary sharp corners. Use the "Preview" button in MAKE to see areas that are slow.
Quality of cut
Lower quality cuts are much faster than higher quality cuts, but at the penalty of looking uglier and being lower precision. However, when you can get away with such ugliness, use lower qualities. Use Qualities 4 and 5 very sparingly, as they are slow, expensive, and rarely necessary.
Lead in / out geometry
For every material and thickness, there is an ideal length of a lead in to allow the jet to pierce while ejecting the spent material out the back of the lead. Generally speaking short leads are best when working with thin materials, and longer leads are better for thick materials. You will have to experiment for the optimal length, though.
Use a short lead-out after the cut finishes. There is no reason to dwell after the part has broken free.
While tangential "U" shaped arc-lead ins may seem to make sense because there is no need to slow the machine down for a sharp corner, they actually produce quite ugly results. A near perpendicular "V" shaped lead is actually much better in most cases. This is because as the jet nears completing the feature, for arc style leads it will try to "cheat" and skip into where it has already cut. With a "V" shaped lead that is near perpendicular to the edge of the part, it does not have such an early opportunity to cheat over into where it has already cut. The exception to this is when cutting super thin materials such as foil.