Toolchanger Setup Continue...

Chriss

Hi *,

My toolchanger setup goes forward slowly, the hardware is mostly done now and I think about the configuration.
I wounder now where I should expect x0 y0. I see it at the moment at the z-endstop on the coupler.
My idea was to use that as the startpoint and set the offset than per tool. Or would it make more sense to use T0's nozzle as y0 x0 and configure the offset of the endstop and the three 0ther tools from there?

I'm not sure what would make more sense. My uneducated guess is variant 1, with 0 at the microswitch, that would make it more generic, would need to calculate one one offset when I replace the tool.

How have you done it? Or how would you do it and why.

Cheers, Chriss

Chriss

I have the feeling that I should use Z according to:
https://docs.duet3d.com/en/User_manual/Tuning/Defining_tool_and_Z_probe_offsets

Chriss

I use G10 L2 now to define the offsets from the HRP:

G10 L2 P0 X0 Y0 Z2

I tested a bit, the tip of the nozzle is ruffly 2mm deeper than the z-probe. I expected to see a jump of the z high when I select T0 than but nothing happens when I select T0. Z is still at 2mm when the nozzle barely touching the bed. Did I miss understand something?

Cheers, Chriss

droftarts

@Chriss I'm not that familiar with coordinate system usage (it's more of a CNC thing), but I don't think you should be using G10 P0 L2. This is setting coordinate system (L2) 0 (P0) to the XYZ offsets. However, coordinate systems are numbered 1 to 9, and the default coordinate system is 1. See https://docs.duet3d.com/User_manual/Reference/Gcodes#g10-set-workplace-coordinate-offset-or-tool-offset and https://docs.duet3d.com/User_manual/Reference/Gcodes#g54-select-coordinate-system

L2: this sets the origin of the coordinate system number specified by the P parameter (1 to 9) to the specified X, Y, Z... values

Initially, coordinate system 1 is in use, and all coordinate systems have zero offset from the machine coordinates.

L2 is usually used to set workpiece offsets in CNC machining operations.

This page https://docs.duet3d.com/User_manual/Tuning/Defining_tool_and_Z_probe_offsets doesn't say to use L2. Use L1, or no L parameter as L1 is the default, with the P parameter for the tool number.

Ian

Chriss

@droftarts Thanks for grounding me again. I may have misunderstood the docu of G10.

I may have overlooked that:

In your G10 tool offset setting commands (these G10 commands have axis letter parameters and a P parameter but no L parameter), specify the offsets of the nozzle or cutting head relative to the HRP.

I will drop the L parameter than and see how it behaves than.

Cheers, Chreers

Chriss

@droftarts I'm a bit confused about the concept behind that offset to be honest. My tools get picked up and dropped off correctly as long as I have no offset configured.
It turns into a nightmare if I have offsets configured for obvious reasons.
So I tend to change the offset now in the tpost file and turn it back to X0 Y0 in the tfree file but that seams to me like a ugly hack. It would be far more convenient if the offset would be removed automatically removed when the tfree gets executed.

Cheers, Chriss

engikeneer

@Chriss what you want is to use G53 in front of yiur G1 commands in your toolchange files. That means it considers the G1 command to be in machine coordinates, not tool coordinates, so doesnt apply the offsets.

More generally have you read up on the E3D toolchanger and motion system? You could probably get 90% of the eay there with your comissioning by just cribbing their config files and setup guides. No point reinventing the wheel! There are probably similar materials also available for the Jubilee and other toolchanger printers if you look too.

https://github.com/e3donline/RepRapFirmware-SD

https://e3d-online.zendesk.com/hc/en-us/sections/6186313376413-ToolChanger-Motion-System

Chriss

@engikeneer Thanks for the tip with G53, that is indeed what I was looking for. I id implemented "my way" in the meantime which simply sets the offset to x0y0 in the tool files. But that is a ugly hack indeed.
I had a look at the e3d's git repo to get some ideas how they did it. And they do not use they do not use the G53 there, which is a bit surprising. The command may be to new for their retired product.

Anyway, I will work on the calibration for now and will play with the G53 later.

gloomyandy

@Chriss Have you seen the e3d toolchanger configuration files created by dc42? They may be of interest:
https://github.com/Duet3D/RRF-machine-config-files/tree/master/E3D_Tool_Changer

The associated blog posts might also be worth reading:
https://miscsolutions.wordpress.com/2020/03/02/converting-the-e3d-tool-changer-to-duet-3-with-hemera-tools-part-1/

Chriss

@gloomyandy Yes, I saw Davids configs indeed. I use many of his plastic parts for my Hemeras and did some modding on them. But thanks for bring them back up.

I always struggle a bit with using other peoples configs to be honest. I like to understand how things work in detail. And this printer is not a new build, I convert a RR VCore into a toolchanger, so I have a working config and need to add the toolchanging "only". Anyway, I used Davids settings for the coupler and some more ideas. But you are right, I have overlooked the G53 in his tools related files.

Cheers, Chriss

dc42

@Chriss for clarification, the HRP of an E3D toolchanger is normally taken to be the position of the Z probe switch on the tool pickup.

I use G53 in the tfree and tpost files because I prefer to use machine coordinates in those files, not nozzle coordinates. That means I can adjust the nozzle offsets for each tool to get perfect registration between all the nozzles, without having to update the tool change files every time I adjust them.

G53 is not needed in the tpre files because there is no tool loaded at that point, so no tool head (i.e. nozzle) offsets to apply.

HTH David

droftarts

@Chriss For an explanation of 'HRP' (Head Reference Point) see https://docs.duet3d.com/en/User_manual/Tuning/Defining_tool_and_Z_probe_offsets

Ian