Firmware 1.19RC1 released - please help us with testing!

[dc42]

I've just released RC4. Please try it.

I did consider whether instead of restoring the initial user-requested Z coordinate after the tool change is complete I should actually have the Z axis move; but I thought of some problems with doing that, so I didn't.

G1 R2 is already implemented. However, it needs to be tested on an IDEX machine. The complication is that after changing from T0 to T1 or vice versa, where does the U axis end up? If we switched T0->T1 then we want the new U position to be the mapped X coordinate, not the old U position. If we switched T1->T0 then we want the new U position not to be restored at all but to be left nas it was after execution of the tool change files. I suspect it isn't accounting for this. And then are the other 4 cases of switching between no tool (T-1) and T0 or T1, in either direction.

[Kulitorum]

You could make variables to use in Gcode. This way it could be the responsibility of the free.g to:

1. Store current position to user-named variables.
2. move the head to park position

and post.g

1. move the head back to user-stored position

This would be much more flexible and support different configurations and be the responsibility of the user to support the functions he needs.

I think if you make the following variables available, we would come a long way:

TnX TnY TnZ En where n is the extruder or head number.

For starters the user variables could be just an array of 30 floats that are indexed like data[n] and the user can keep track. - that should be relativly easy to implement and very flexible.

[dc42]

True, but explaining how to use them to novices would be complicated. I prefer to get as close to an "it just works" solution as possible for the majority of users.

[lars]

Just to give you some quick feedback on RC4, my initial move x/y/u tests worked!
I'll recompile it with my modification to get it to work with cura and do a test print and report back when its done.

[dc42]

Thanks for the feedback. I think I've cracked this one at last - provided that the user (can't remember who) who reported tool Z offsets not working is happy with it.

[lars]

Hmm.. something is going wrong after I pause and stop a job. I do a few extrudes on both tools (maybe up to 10mm) to prime the tools. When I do "print another" it moves to where it should start and do a huge retract! Is there some code that tries restores the e0 and e1?

M190 S63
M104 S210
M104 T1 S210
M109 S210
M109 T1 S210
; G28 ;Home
G1 Z15.0 F6000 ;Move the platform down 15mm
M83
T1
G1 E2
T0
G1 E2
M82
;LAYER_COUNT:420
;LAYER:0
M107
M104 T1 S180
G0 F6000 X221.18 Y236.445 Z0.3
;TYPE:SKIRT
G1 F1800 X220.667 Y236.983 E0.01398
G1 X220.193 Y237.581 E0.02834
 

Edit: retract was on T0
Edit 2: I get retract on T1 too

[lars]

Ok, Ill put that in the start g-code… Are you planing to go back to old behaviour (where it worked without G92 E0) for this (pre RC) or keep it this way?

Edit: Plenty of G92 E0 just to be sure it works

G1 Z15.0 F6000 ;Move the platform down 15mm
M83
T1
G92 E0
G1 E2
G92 E0
T0
G92 E0
G1 E2
G92 E0
M82
 

[dc42]

Absolute extrusion in 3D printers must rank as one of the worst ideas ever. Whoever thought it was a good idea was a moron. It causes problems with supporting pause/resume, resume after power fail, mixing extruders, and filament change support. Please nag the Cura developers to add support for generating relative extruder coordinates.

You and the Cura developers between you have fallen into one of the traps of using absolute extrusion. The first extrusion command generated by Cura (G1 F1800 X220.667 Y236.983 E0.01398) does not have a G92 E0 command before it to define the datum for that extrusion command. You should insert a G92 E0 command in your start gcode after the M82 command.

EDIT: your post crossed with mine.

[lars]

@dc42:

You should insert a G92 E0 command in your start gcode after the M82 command.

Will that reset it for both tools?

[dc42]

No, only for the current tool. RRF maintains separate cumulative extrusion amounts for each tool. AFAIK nobody has ever defined whether this is what 3D printers are supposed to do, or whether a single value should be maintained. Yet another problem caused by using absolute extruder coordinates. Relative extruder coordinates make things so much simpler.

Your question and my response would not have been needed had your slicer generated code that used relative extruder coordinates. Please nag the Cura developers to add support for relative extruder coordinates.

[Kulitorum]

Ok, it seems RC4 works for me too. I have not done a full test with pausing etc, but for just normal printing it seems to work.

And the "tool Z offsets not working" bug was reported by me, so you can strike that off your list.

Thank you

[dc42]

@Kulitorum:

Ok, it seems RC4 works for me too. I have not done a full test with pausing etc, but for just normal printing it seems to work.

And the "tool Z offsets not working" bug was reported by me, so you can strike that off your list.

Thank you

Thanks for the feedback! Got there in the end.

Unless I receive any more problem reports, I intend to release RC4 as the 1.19 release. It's now very similar to 1.19beta11 apart from the tool change Z offset fix and refactored homing code to support SCARA.

[lars]

Yep, looks like basic printing works now, have not tested to change offsets. I'm out of time now…

I'll let the cura developers know of your hatred of absolute extrusion at first opportunity I get!

The following start code should prime and reset both tools..?

G1 Z15.0 F6000 ;Move the platform down 15mm
T1
M83
G1 E2
M82
G92 E0
T0
M83
G1 E2
M82
G92 E0
 

[dc42]

Yes, that looks good.

Your question and my response would not have been needed had your slicer generated code that used relative extruder coordinates. Please nag the Cura developers to add support for relative extruder coordinates.

[burtoogle]

I have made some contributions to Cura and one of the recent changes is that it now really does differentiate between Marlin and RepRap flavour gcodes. Until recently it had RepRap(Marlin) flavour that has to conform to various Marlinisms and so wasn't really that well matched to RepRap. It now has separate Marlin and RepRap flavours and so there's no obvious reason why the RepRap flavour gcode could not support relative extrusion. I shall investigate and will keep you posted.

[dc42]

Thanks, that would be great!

Another good feature would be to write T0 to the Gcode file before any temperature-setting commands, if no T commands would otherwise be written.

[burtoogle]

@dc42:

Another good feature would be to write T0 to the Gcode file before any temperature-setting commands, if no T commands would otherwise be written.

OK, I'll look at doing that as well.

[dc42]

Lars and Kulitorum, please can you each post about 20 lines from the gcode files you are printing around the point where your slicer generates a tool change. I may be able to simplify the absolute extrusion distance tracking a little, but I need to know what Cura is doing with the extrusion distance when it changes tools.

[burtoogle]

@dc42:

Lars and Kulitorum, please can you each post about 20 lines from the gcode files you are printing around the point where your slicer generates a tool change. I may be able to simplify the absolute extrusion distance tracking a little, but I need to know what Cura is doing with the extrusion distance when it changes tools.

Just checked the current Cura code and it resets the distance to zero on extruder change.

[Kulitorum]

Hmmm, homeing takes forever in RC4…. Maybe it's just me, but in my latest tests, the printer would home X, then just sit there for maybe 30 secs before homeing Y. This is when sending a G28 command. Pattern repeats for other axies.

Anybody else see this?