For some time I have been working on modifying the MPCNC to a Dedicated Rotary 4th axis lathe.
Using the firmware 515S as a base, after modifying the source, I have a working firmware that maps the A Axis in rotary degrees.
Free Software that can accurately wrap the tool path for this using a helical path for true rotary, none are good and have been discarded. If you just want to do surface engraving, F-engrave and Gcode Ripper works quite well.
For true rotary sculpture work, and ornamental turnings the only option is paid software. The choices are- Vcarve Desktop ($375, no true helical path, limited in post processors), or Deskproto ($270, true helical paths). The free testing Deskproto can put out the gcode as “ISO Plain Gcode” which loads and runs good through CNCjs. The paid version is able to output gcode that extends past the center axis for good sculpture work, and such things as Queen Anne/French Provincial table legs, ornamental turning, and decorative spindles. Deskproto is also able to simulate the rotary toolpath.
With all that said, I have decided to modify a smallish metal lathe that I have, that the DC motor control failed on that has been sitting under the bench for a couple of years. Alternatively, I am also working on special head and tailstock options.
More to follow as the build progresses
JohnS
Oh wow that sounds awesome! Keep us posted! Looking forward to following along this one!
Well this may be good news for those of us doing 4th axis.
Bonus in Deskproto, also has a gcode sender with true 4th axis visualization
sweet!
250 Euro. Oof.
yeah unfortunately
Cheaper than Vcarve
OK, spent some time the last couple of days doing serious testing, and configuration on DeskProto.
To start according to Lex there at Delft Spline, Deskproto doesn’t have a Marlin postp or a Machine Profile that would run the MPCNC or the Lowrider.
So not to be denied, I studied the Machine profiles available and the postp’s they used. Old habits die hard, and figuring out what makes this software tick became a bit of an obsession.
I had modified the 515S firmware to have a working A-axis. This works and steps by degrees through pronterface and cncjs using standard console commands. Serious computation of step/angle took a bit, and would be different for various 4th axis heads. Mine is a 4:1 Rattmotor axis I got off of Amazon.
There are 2 possible Machine profiles that can be used in a modified form. As one of them uses marlin gcode format (Snapmaker), I copied it, and modified it for the MPCNC 3 axis and MPCNC-Rotary 4 axis, as two separate machines, within Deskproto. Once that was set, I copied the post processor, then modified it with custom start and end gcodes similar to Estcam, and setup the max speed rates.
Deskproto is strictly CAM, most models in SVG, STL(binary), DXF, Ai, EPS so most folks who use those can import them direct. 3mf is not currently supported.
Have setup almost all of the files I had for a Isle of Lewis chess set in about 30 min. The “wizard” walks you through orientation of the model, adds the tab for chuck clearance, and can generate the gcode, and simulation.
After finishing the wizard, you can change the step-over and toolpath strategy It will ramp in the cut, and do a helical roughing, and helical finish toolpath fairly quickly. All standard toolpath strategy’s are available.
Deskproto can also send the gcode directly to the machine, using standard COM over USB using 256000 baud. Tested this am works slick
Super excited about this software solution, much better then figuring PI and running as flat wrapped gcode using Y as A.
Firmware mod was for the SKR 1.2 Pro running single steppers for each axis, i.e. in series.
Full write up on the build, firmware, and Deskproto mods to follow as soon as I build this and do complete testing.
JohnS
Does it already have PP for GRBL/FluidNC?
Can it be done with dual endstops/1 driver per axis and use the 6th driver as rotary?
GRBL yes, FluidNC no.
On the A-Axis driver possibly, haven’t gotten that far, as the setup I’m going to do uses single/series
I believe standard GBRL works with FluidNC so that shouldn’t be a problem
Is this the one you are using?
If so I’m curious to see how you end up liking it That’s a much better price than I was expecting
Yep, that is what I got. I had an extra stepper motor for the builds I have done, replaced the stock one on it because it didn’t have a connector.
After several regular world car repairs, a month of various illnesses, and an outbreak of shingles, I hope to start assembling the dedicated rotary lathe this weekend.
One thing the creator of these shells forgets to include is the End of Warranty at 50 years old. Now I am now of the age that various parts are no longer available, and the orphan parts hasn’t caught up. Such is life
I know those feels.
I had shingles at the beginning pf November. That sucked. I’m sick again now with something the kids brought home before the break.
Or for a similar budget you get one of these and play with chisels
Just kidding!
I am thinking to add a removable 4th axis, removing part of the table surface. The goal is mainly surface engraving, but it would also be very cool to be able to carve on the surface of a piece manually turned on the lathe.
It means modeling the existing piece and then adding carving on it though, is it a common practice?
Could you share some pix of your rig, and the main hardware used?
Great Work! I can’t find the 4 axis(rotary) firmware for the SKR 1.2 Pro board…
Are somewhere a tutorial How to config the “A” axis for a rotary?
Thanks in advance, Mirko.
I did the firmware mod myself. As I haven’t fully tested the configuration, it hasn’t been posted.
A few things had to be put on the back burner this winter, hoping to get back to this soonish