Flying extruder with 4th axis

ander

I just found and ordered 4 lead screw of 1m long, is going to move so much faster, and this way i don´t have to change anything to the original setup for now....after uploading the firmware we will see if aditional features are needed when testing like some system to help the motor not to be super bowncy

ander

Hi there!!
I just received the lead screw, tomorrow i will change it so the 4th axis can move so much faster.

@dc42 , did you have any chance of working on the firmware?
i had to cut the 1.2m teflon tube that was going from the motor to the hotend to make the modification and now the printer is not working ever since.

dc42

@ander said in Flying extruder with 4th axis:

Hi there!!
I just received the lead screw, tomorrow i will change it so the 4th axis can move so much faster.

@dc42 , did you have any chance of working on the firmware?
i had to cut the 1.2m teflon tube that was going from the motor to the hotend to make the modification and now the printer is not working ever since.

I'm sorry, I won't have time to look at this until the 2.02 release is finished.

ander

Hi there!!
Did you have any chance to look at the 4th axis firmware? My delta is stopped since then

dc42

Yes, I have a build of RRF that supports up to 6 axes on a delta. Still some testing to do, but maybe you can help me with that?

ander

Hi There!
Of course i can help, my printer is ready for testing, tell me what to do and i will tell the results.

dc42

Please follow the instructions at https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareDeltaPrinter?revisionid=HEAD#Section_Adding_additional_towers_to_carry_flying_extruders and use the binary at https://www.dropbox.com/s/fyvibzm0zl92hiy/Duet2CombinedFirmware.bin?dl=0. Caution: this is mostly untested! I suggest you test it at low speeds and reduced motor currents, and that you do not mount the extruder on the 4th carriage yet.

Monster Delta

which motor output would i use on the duet wifi or would i have to use a duex 5

dc42

Use M584 to create a U axis using any available motor output.

EDIT: I've just added some more to that new section on the page I linked to earlier.

ander

Hi there
M584 can be used to create a new axis but, where exactly i have to add that, in config.g after M669?

dc42

Put the M584 command near the start, before M665, M666 and M669.

ander

Hi there
I succesfully created the new axis, i can see in the machine status that i have a new axis called U.
when starting the printer the U position is marking 0.00 endstop pushed or not(the led brights on the duet en pushing so the conection is fine) while the other axis in n/a.
I put in homedelta.g the U axis to be homed, but when trying to home all the axis, the only ones they home are the normal ones. i try to home manually the U axis and shows me the error: Homing file homeu.g not found. And i cannot move it manually either, not to the positive side neither the negative

dc42

Please post your config.g and homedelta.g files.

ander

Hi
I´m also getting another error that says could not update homedelta.g.
Here i´m adding what you asked me, just keep in mind that i have an endstop switch in the extruder, similar to what the atom printer mounts.

1_1549013751464_config.g
0_1549013751464_homedelta.g

dc42

@ander said in Flying extruder with 4th axis:

I´m also getting another error that says could not update homedelta.g.

That probably means that the printer is still executing homedelta.g. You can use the Emergency Stop button to reset it.

You need to add the correct U parameter to the following commands in config.g:

M92 M906

and optionally also add a U parameter to M350.

Your M574 U parameter should be U2 because it is (or should be) at the high end of the tower.

dc42

PS - also:

I suggest you add parameter P3 to the M584 command in config.g to hide the U axis. Then insert M584 P4 near the start of homedelta.g to un-hide it, and M584 P3 after the second G1 S1 line.
Remove the U-5 parameter from line 9 of homedelta.g. That G1 command is a normal move command (no S1 or S2 parameter), so U will track Z.

ander

Still doesn´t work, the U axis is not showing in the beginning, then it shows, tries to home and says it can´t after a while....i found some error....if i push the endstop of the U axis the z probe switches in the duet control panel. but the conection is in E0 so it is right

ander

G28 U
homing file not found
it is giving that error, here goes my files after doing those changes, i still have the problem i sayd before about the endstops
1_1549017082633_config.g
0_1549017082632_homedelta.g

dc42

Don't try to home U by itself using G28. You have already updated your homedelta.g file to home U concurrently with XYZ.

Here is how to test the U axis:

Send M584 P4 to make the U axis visible.
Send G91 to put the machine in relative mode.
If you send G1 S2 U20 then the U carriage should move up 20mm. If you send G1 S2 U-20 then it should move down 20mm.
If that works, try G1 S1 U100. The U carriage should move up for 100mm or until the U endstop is triggered, whichever happens first.

dc42

I'm simulating your setup on my bench. After making the corrections to the config..g and homing files, I found a couple of issues:

The M208 U axis limit needs to be set high so that it doesn't artificially limit the U axis movement. So I suggest you add U1000 to your M208 S0 command. I will put a fix for this in the next build.
There is something odd happening at the end of homing that causes it to remain busy for about a minute. I am still investigating this.

Once homing is complete, it appears to work properly. On pure Z movements, the U motor moves with the other three. On XY moves, the U motor moves down by an amount depending on the XY distance from centre.