If you don’t want to read everything below
Due to some awesome software updates our machines should now run so much more reliably and accurately.
Just a little wrap up of some major software changes that have recently taken place.
After trying to update the firmware to RC8 to try and fix an LCD refresh issue that was causing laser artifacts we found out we had a major software issue. The whole time the MPCNC has existed our speeds/rapids have been less than idea. Marlin, the firmware we use on the ramps stack, does not use rapids or G0 commands like most CNC firmware does. On top of that we have different feed rates for our XY and Z axis. We had been dependent on the firmware to limit the max speeds of our axis. So we had been using the same, much faster, speeds in our gcode to run the XY and Z axis. When I updated to RC8 the firmware it is much more sensitive to over use of the firmware limiting.
This has been the cause of many peoples problems with the Z axis. Issues meaning missed steps, grinding sounds, and weak movements. Those of us that didn’t have z axis issues were usually just running all cuts conservatively. That means we weren’t hammering the firmware with limiting out moves. Those of you trying to push the envelope had more Z axis issues.
Simple solution, update your software. And stick with RC7 firmware unless you are using the laser for raster images then use the RC8 only for that.
Christian has helped us out once again and updated his software to accommodate our machine. All lines now have speeds assigned and we can independently set the XY and Z rapid feed rates. I have updated the Estlcam Basics page to show you how to use the new settings. Please update to .37 or newer.
The Fusion 360 Post processor also received some serious group effort and has had a pretty major overhaul and now works flawlessly. Two options for this one, V9 or V10 from the main thread (or newer), or Martin DB started from scratch. I have only made real cuts with V9, I feel it is safe to assume the others work as well. The changes are all in the threads but comes down to cleaning up some hard coded moves that are no longer needed, and the creation and separation of the rapids on the XY and Z axis.
So what does it all mean. If you are using my firmware here are some hard numbers. Max XY speed is 190mm/s and Z speed is 8.5mm/s, MAX. This is your max speed for rapids, you do not have to move this fast, in fact, it is best that you don’t. Our steppers rapidly lose power at above 60 RPM’s. 60 RPM’s is equal to 32mm/s XY and 1.4mm/s Z. So for max power you should cut at no faster than 32mm/s XY, if you need to push harder than that do not go faster, go deeper, or use a bigger bit.
With all that said, I have never had any power issues on the XY axis, and the “power” issues some of you had on the Z axis were most likely caused by bad Gcode nothing else. The Z axis has a huge mechanical advantage, anyone who has crashed into the bed slowly knows it can rip the machine out of it’s boots. I wish I would have looked into this much earlier, people’s Z axis issues were the cause/inspiration for most of the re-designs…