I’m using Inkscape/SheetCAM and trying to cut holes (20mm diameter) in 3/8 steel. I’ve discovered this is basically impossible. So now I’m trying to simply mark the hole centers for mag drilling. I recognize the SheetCAM post processor doesn’t support drill operations, so my first attempt was to modify the post processor and add drill support. I tried a number of techniques but to no avail.
I’ve read in these forums that Andrew recommends cutting a 0.01mm diameter hole at the center location. I used this technique in my custom post processor but couldn’t get it working reliably, so then I created a drawing with 4 evenly spaced holes of 0.2mm diameter (smallest I can make in Inkscape and still have the drawing usable). The cut results are unusable. The “holes” are not round and certainly not evenly spaced. There’s no way I could use them to accurately drill holes in the part.
So my question is, how should I be doing this? I’m looking for specifics including tool settings like feed rate, pierce height, delay, etc.
You may be running into issue with lead-in on you holes.
You have to tell Sheetcam not to include a lead.
20mm in 3/8 “ should be no problem if your cutter is set up right. You need good consumables proper air and correct speed to do it tho
In fact if the simple pierces are not coming out round and misplaced then almost certainly your Consumables are worn and the arc is shooting out sideways…
I have no lead in defined in SheetCAM for the holes. I’ve had one “good” hole cut out of 10 at 20mm diameter. That’s not good enough. I’ve checked and rechecked the air. I’ve replaced consumables. I’ve played with speeds too, but I can’t get consistent results.
Pierces are in no way coming out round. Consumables are good. There’s so much dross that comes out of the hole as it’s piercing, it screws up the arc and the hole.
I have no problem doing this in 3/16” steel, but the 3/8” is kicking my ass.
I’m not using the tune settings, it’s all defined in SheetCAM. 55amp, 72psi, 1mm tip, 850mm/min feed, 1.2s pierce delay, 2.5mm pierce height, 100mm/min plunge, 1.524mm cut height.
When cutting the 20mm hole, I used a lead in starting at the center of the hole. When trying to “cut” a .2mm hole, I use no lead in.
Those settings are my general settings for 3/8 steel. I’ve varied many of them during testing with no clearly better settings.
Here’s a related question. Like I said up above, I’m working on adding drill capability to the ArcDroid post processor. I’ve attached the gcode for one of my test cases, 4 “holes”, 10mm apart in both X and Y directions. The gcode loads on the ArcDroid, but when it runs, the machine moves to each hole location but does nothing else; no z probe, no plasma arc, nothing. And if I then change the z level with the knob, then rerun the program, it runs again but the z level never changes. What’s going on?
