For the first questions....and I don't recall if I ever answered this specific post..
The mechanized cut charts in all of the Hypertherm manuals...including the Powermax65 list the cutting amperage. I am reading the Powermax 65 chart right at the moment....it says "65 Amp shielded consumables" at the top of the page....then scrolls down to individual settings for various thicknesses from 16 ga to 1".....all of which are cut at 65 amps but at different speeds, pierce heights and pierce delay times. If the chart is for using the 65 amp consumables....then all of the specifications in the chart are for an amperage setting of 65 amps.
The issue that a lot of users run into....is that there are a lot of different cnc plasma cutting machine designs....and many of them simply cannot cut with any level of accuracy at high speeds. One of my cnc machines cuts well at up to 320 inches per minute, the other gets unstable above 140 inches per minute.
So.....if you have to slow the machine down to get the best cut path following ability....you then should reduce the amperage in an attempt to match the plasma process to the cut speed capability. If you are using a 65 amp nozzle and you turn the amperage below 65 amps....the plasma arc loses energy density (rated as amps per square inch) and is not as stiff, and has lower gas velocity. This tends to produce a wider kerf, warpage and a less square cut edge.
The cut chart in front of me says to cut 16 ga steel at 65 amps at 370 inches per minute. neither of my cutting machines will do that.....so my choice is to simply reduce the amperage and try cutting slower.....or to put in a nozzle that has a smaller orifice and a lower amperage rating.....allowing me to cut at a speed that my cutting machine can handle.
The choices with a Powermax65...use the 45 amp shielded parts on that 16 ga.....the chart says 350 inches per minute....still too fast.....so I look at the FineCut consumable chart and it says 250 inches per minute for 16 ga. This is my best choice....it will allow the cutting machine to be stable and the cut quality will be nice.
Could Hypertherm provide cut data that provides the best speeds for cutting 16 gauge with the 65 amp shielded consumables at slower speeds....perhaps 150 ipm? yes.....however we likely would have a couple of hundred pages of cut charts at many various amperage/consumable/thickness ranges and it would make the process even more confusing! I suggest choosing the consumable and amperage and consumable sets that best matches your cutting machines speed capability...and use that combination. Experiment with amperage and speed to fine tune.....but always leave the amperage for a given nozzle at or below its advertised rating....and always cut at the recommended height.
The second part of the post....regarding intricate cutting:
When cutting thin (.060") aluminum with the 45 amp shielded process....I would expect the kerf width to be approximately .038" to .040" if you are ctting at the recommended cut speed listed in the cut charts. If you have chosen to cut slower, the kerf width will be wider. I am assuming that you have a Powermax45 as you mention using the 30 amp consumables.....if so these consumables will provide a kerf width that is about .006" to .010" narrower as compared to the 45 amp shielded consumables....they should help with more intricate parts.....however, cutting .060" away from an edge is asking too much from the plasma process. The .060" strip of aluminum will get very hot, will likely warp and will have heavy dross. I try to keep my cuts at least 1/8" (.120") away from an edge. A laser or water jet process can handle much finer details than a plasma on thin materials....at a much higher operating cost and purchase price.
We are talking about air plasma cutting systems here on entry level...low cost cnc machines. There is another whole side to plasma cutting with high definition plasma cutting on precision industrial cnc cutting machines....many of which can maintain great accuracy at cutting speeds up to 500 inches per minute!
The questions were rather complex on this post....so my answers can be a bit convoluted....i'd be happy to clarify any areas that need clarification!
Best regards, Jim Colt
Picture of an aluminum cut with the 45 amp shielded process at 45 amps....090" aluminum with good detail.