Tool Calibration Station E3D Toolchanger

[Danal]

G38 series, at the moment, can only work with a Z axis endstop, or Z axis probe. I'm not a million percent clear where your station goes... but... I suspect that your Z axis will still need a switch separate from the station's probe.

Multi probe support looks like it is coming soon (the K parameter on the probe definition) but it is certainly not there yet.

You COULD re-define the endstop/probe while using the station, and define it back to Z when finished with the station. Having done this in the past, anything that causes the "define back to z" to be skipped will lead to a physical Z crash at the next home.

That's why I chose G1 H3, even with its other side effects. Lesser of two evils.

[Danal]

And... if the metal platform clicks the switch, and the nozzle tip is visible to the camera, I am inferring that the nozzle TIP is not what hits the metal and switch?

If that statement is true, how does this calibrate for different length nozzles?

[smoki3]

@Danal said in Tool Calibration Station E3D Toolchanger:

And... if the metal platform clicks the switch, and the nozzle tip is visible to the camera, I am inferring that the nozzle TIP is not what hits the metal and switch?

If that statement is true, how does this calibrate for different length nozzles?

So the calibration of the z axis is independent from the XY axis. You calibrate the Z Axis, the you place the nozzle above the camera und calibrate XY Offset.

Ate you sure that the G38 is not working with multiple probes? According to documentation it is working. I have to wait for my new rpi zero then I can wire everything and test the gcode

[Danal]

@smoki3 said in Tool Calibration Station E3D Toolchanger:

According to documentation it is working.

It will need a lot of experimentation. I did some when developing those macros... but... several x.x.X have passed, and the use cases are a tiny bit different.

Keep us posted!

[smoki3]

So I made some process today.

I connected my probe.
It works pretty fine with G38.2. So it should be easy now to calculate the Z Offset.

I also made some reliable test.

22.2.2020, 09:08:07	M409 K"move.axes[4]"
{"key":"move.axes[4]","flags":"","result":{"acceleration":400.0,"babystep":0,"drivers":["4"],"homed":true,"jerk":8.0,"letter":"V","machinePosition":27.392,"max":34.0,"min":0,"speed":1200.0,"userPosition":27.392,"visible":true,"workplaceOffsets":[0,0,0,0,0,0,0,0,0]}}
 
22.2.2020, 09:07:53	M409 K"move.axes[4]"
{"key":"move.axes[4]","flags":"","result":{"acceleration":400.0,"babystep":0,"drivers":["4"],"homed":true,"jerk":8.0,"letter":"V","machinePosition":27.390,"max":34.0,"min":0,"speed":1200.0,"userPosition":27.390,"visible":true,"workplaceOffsets":[0,0,0,0,0,0,0,0,0]}}
 
22.2.2020, 09:07:39	M409 K"move.axes[4]"
{"key":"move.axes[4]","flags":"","result":{"acceleration":400.0,"babystep":0,"drivers":["4"],"homed":true,"jerk":8.0,"letter":"V","machinePosition":27.392,"max":34.0,"min":0,"speed":1200.0,"userPosition":27.392,"visible":true,"workplaceOffsets":[0,0,0,0,0,0,0,0,0]}}

Looks like the repeatability is very good just a deviation of 0.002mm.

But I also noticed some issues:
I can not probe my titan aero on the tool changer due to the too short axis. I have the same issue on Gregs brush station. So I have to redesign the arm a bit to bring every thing more upwards.

I wrote a short macro:

G1 X-29.5 Y124 F30000
G38.2 P1 V34
 
G10 P{state.currentTool} Z{move.axes[4].machinePosition-44.23}
 
G91
G1 V-2 F1000
G90

With this the tool offset is applied.

[smoki3]

So next problem:

M500 doesn't save the tool offset. It there a way to save it?

[jay_s_uk]

I usually take a copy of the output from M307 and then manually edit the config override with the correct values.

[smoki3]

@jay_s_uk said in Tool Calibration Station E3D Toolchanger:

I usually take a copy of the output from M307 and then manually edit the config override with the correct values.

To copy manually isnt what I understand from a automatic probe.

Anyway M307 reports just the Heating parameter and not the tool offset. These a reported with G10 Px. But I need to save it

[jay_s_uk]

@smoki3 sorry, of course it is.
I don't think tool offsets are currently supported by M500.

You'd have to request it to be added by dc42 or look at writing some conditional gcode when variables are implemented in 3.02

[dc42]

The S-2 option of the G30 command at https://duet3d.dozuki.com/Wiki/Gcode?revisionid=HEAD#Section_G30_Single_Z_Probe may be what you need. If you use G30 S-2 to set the tool Z offset, then a subsequent M500 will save the offset in config-override.g. You can also save it explicitly using M500 P10.

[smoki3]

@dc42 I get the tooloffset applied with meta commands easily. I just want to save it to config override.
Will try it tomorrow with M500 P10

[Danal]

What is the 44.23 constant?

Or, same question phrased another way: Is it possible to have the station calibrate itself?

[smoki3]

@Danal said in Tool Calibration Station E3D Toolchanger:

What is the 44.23 constant?

Or, same question phrased another way: Is it possible to have the station calibrate itself?

The offset between the Z Probe and the Tool Probe.

I think think this is not possible duet to both micro switches and to the fact that the my V Axis is too short