@alankilian

I followed your suggestion and a lookup table to pick the initial potentiometer position and then fine tune the spindle RPM with a loop.
This worked well enough for some initial tests. But for me, it was no satisfying permanent solution.

After taking some voltage measurements, I figured that the motor controller simply needs a 0-5V Control Signal. 🤦

So I used a PWM to analog converter to provide the control signal and to galvanically separate the inverter from the Duet Board.

I am using a multifix toolpost to quickly change between tools. In order to avoid manually calibrating a new tool, I wrote a macro that can automatically set the offsets for a given tool using a touch probe. Since the multifix toolpost is very repeatable, the offsets do not need to be recalibrated after a toolchange.

IMG_20220809_180950.jpg

I am very happy how this project turned out. The Duet3HC is a formidable controller for small CNC-Maschines. 😀 👍

Video: Paulimot CNC-converion test.mp4

IMG_20220919_204618.jpg

IMG_20220921_202237.jpg

Cheers
Max

That's great information, thank you @markz

I would comment out the last two lines and then add a line to run the end.g macro, to send the spindle to its safe position, then.

I imagine this should work:

+--------------------------------------------------- + Commands output at the end of the file +--------------------------------------------------- begin FOOTER "M5" +-- "G0[ZH]" +-- "G0[XH][YH]" "M98 P"end.g""

With the end.g macro looking something like this:

; end.g G1 Z{max(move.axes[2].userPosition+5,move.axes[2].max-5)} F2400 ; move the Z axis to a safe height G0 X273.5 Y560 ; move XY to a safe place

I'm still working on the probe macro...

@Sejl you don’t need a special post processor, just use a fanuc one and remove the canned cycles. All the Gs and Ms in every line are no longer needed, it behaves as a normal industrial Cnc, once a command is sent, all the lines following are under that command, unless you change it again.

@ian-0 Hi, I don't think it's skipping steps. That would produce some of the desired path.

I'm not entirely clear on what it's actually doing. Are you saying that it cuts the two grooves we see then comes back and cuts them again and again and then it stops? That would be bizarre. It could be that it's deciding the cnc hasn't parsed those two chunks and it sends them repeatedly until it gives up I suppose.

I'd also vote for seeing your config.g file for RRF.

One simple test you could do is manually move the CNC head - following along the G-code roughing file - just send each line individually in the console, except the Z offset, (without the N prefix) and see how the head moves.

mark

@crap Yeah, I'm not too familiar with CNC. Since RRF is primarily oriented to 3d printing, I think some of the CNC functionality might be a bit behind the overall industry.

@Jengland I do have it
I use the following method:

I set the machine zero with setter and spindle without the tool / collet / nut I install the tool I test the tool and set tool height

If I change the tool, I just redo p2 and p3

It does require additional step on the machine enable (p1), but It happend that my setter is +- 0.01, and Z endstop about +- 0.1-0.3

My script

M208 Z8 S1 G53 G90 G0 X321.0 Y0.0 if !exists(global.MGlobalsLoaded) M98 P"/macros/Measuring/globals.g" ;M558 P1 C"io7.in" H23.258 F{global.MSpeedFast,global.MSpeedLow} M558 F{global.MSpeedFast} K1 M300 S300 P1000 if state.currentTool = -1 M291 S0 T5 P"Probing the spindle zero height" else if global.HSpindle <= -9999 abort S"Please set the spindle zero first" M291 S0 T5 P"Probing the tool " ^ state.currentTool ^" offset" M558 F{global.MSpeedFast} K1 G30 S-1 K1 G53 G1 Z{move.axes[2].machinePosition+2} H4 M558 F{global.MSpeedLow} K1 G30 S-1 K1 if state.currentTool = -1 G92 Z{sensors.probes[1].diveHeight} set global.HSpindle = sensors.probes[1].diveHeight set global.MResultZ = sensors.probes[1].diveHeight M208 Z30 S1 else M400 echo "Probe triggered at Z:" ^ move.axes[2].machinePosition ^" Sensor height: " ^ sensors.probes[1].diveHeight var ToolLen = move.axes[2].machinePosition - sensors.probes[1].diveHeight set global.MResultZ = - var.ToolLen M98 P"/sys/tool_set.g" T{state.currentTool} O{global.MResultZ} ; Set soft limit to 0 plane M208 Z{var.ToolLen} S1 M558 F{global.MSpeedFast} K1 G53 G1 Z{move.axes[2].max - 10} H4

Endstops already telling that they were triggered was the thing. Thank you!

@menthos I have updated the documentation at https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m675-find-center-of-cavity.

This might provide a possible solution. https://github.com/rclone/rclone ??

Definitely want to avoid having to reinstall everything again in the event of an SD card failure!

And here are the sys files.

@sdj tpre2.g tpre1.g tpre0.g tpost0.g tfree1.g tfree0.g Probe.g config.g

So it's working 🙂 I switched the Endstop of the Y-Axis to Y Positive and inverted the endstops in the configuration.

@p0rr1dg3 I have an Ooznest Workbee CNC. It is configured with soft limits which prevent the machine from moving outside the machine limits.
What version of Duet Web Control are you using?
In CNC mode, we have machine coordinates (the actual physical limits of the CNC) and work coordinates, which are job specific.
When you set your X0 Y0 and Z0 they fall within the machine coordinates and you will get an error notification when the machine is given a command to move out of bounds.
Your work coordinates CANNOT exceed your machine coordinates limits.

Edit
I see you're using very old firmware. Please upgrade to the latest stable firmware and your issues will be solved.

@jay_s_uk thanks for this great link.

@nightowl after solving some other issues I made my own configuration with RRF and compared it with your config. Now i made the upload and have to wait until i am in front of my machine.

@jay_s_uk thanks..

that is a real bummer... so much wasted potential...

@cncmodeller That's probably a better aproach then the heater/thermistor idea in the other thread, but it would require FW adaption.
A spindle definition would then be a combination of Fan.rpm reading and heater PID algorhythm.

@cncmodeller You are basically looking for a frequency2voltage converter or DA converter.
How many pulses do you get at full speed?