Flying extruder with 4th axis

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.

ander

I does work but the motor its being moved from E1 driver, and the endstop that reads for the U axis is the E0 endstop

ander

By the way, i couldn´t respond yesterday because the forum was blocking my messages by marking them as spam,i tried to unlog, log back again, reboot the computer etc. but didn´t work, it looks like now runs fine, i don´t know why.
apart from all you sayd to change i had to add some more features to the code for the U axis, like M92 M 566 M203 M201 M906.
i will put my code back again so anyone can look at it. I forgot to add the M906 and i realized that he was trying to move but with no success, so i added the milliamp value and started working.
The only thing that looks is stopping from working properly is the endstop thing.
The E0 endstop is needed for the autolevel function, so i cannot just use it as U axis endstop
1_1549104900494_homedelta.g
0_1549104900493_config.g

dc42

@ander said in Flying extruder with 4th axis:

I does work but the motor its being moved from E1 driver, and the endstop that reads for the U axis is the E0 endstop

That is exactly as it should be. Endstop inputs are allocated in the order that the corresponding axes are created, regardless of which motor outputs are used for the corresponding motors.

dc42

@ander said in Flying extruder with 4th axis:

The E0 endstop is needed for the autolevel function, so i cannot just use it as U axis endstop

You can use either the E1 endstop or the Z probe input for your Z probe instead (or the Z endstop input if you don't have a Z endstop switch). See the description of the M558 P parameter.

dc42

I've fixed some bugs in the additional tower support and put a new binary at https://www.dropbox.com/s/fyvibzm0zl92hiy/Duet2CombinedFirmware.bin?dl=0. I think it is all working now.

ander

Hi there
i still have the same issue, i don´t know how exactly change the endstop thing.
Looking on machine status, and pushing by hand the U axis endstop, where Z-probe value is, shows a change from 0 to 1000.
Homing all the towers works fine, the compensation of the U hight when moving X and Y axis seems to work fine too, but the bed leveling doesn´t work, it crashes against the bed and not stopping when the effectors switch is pushed.
Pushing M584 P4 , (head position U) shows a value of 0, after homing shows a value of 747.00, and it doesn´t change even if i move the axis(i don´t know if it´s the way that should work).
Settings/Machine properties, pushing U axis endstop shows E0 "endstop hit" changing to yes.
After using the comand homing, it is showing me the E1 values too, if i touch the efector´s switch by hand " Endstop hit" changes to yes(conections are fine), Minimun and maximun values are n/a just in E1, everything else looks identified.

Pd:
By the way, this has nothing to do with all the setup we are working on but sometimes randomly looses conection with the duet and you need to reconnect.

dc42

If you have connected the Z probe to the E1 endstop input, then you need to use P4 C4 in your M558 command.

ander

Cool, it works almost fine, but it says that the endstop is allready triggered when doing the mesh levelling

dc42

Does the Z probe reading indicate correctly when you operate the Z probe switch?

If your printer is out of calibration then you may need to increase the dive height in M558 temporarily to probe from a greater height.

ander

I does work fine, triggerring by hand now Z probe changes to 1000 from 0.
The weird thing is that the bed levelling was working correctly before and not anymore.
What value is the height value, the F or the T?

dc42

The dive height is the M558 H parameter.

ander

Hi there!
i changed it from 5 to 6, it looks that works fine so far, i have to adjust some parameters like speeds etc. and when it is possible i will post a video of all the setup working.
Looking really cool.
thanks for the help

ander

Hi there
Yesterday a realized that the height it wasn´t the problem, the thing is that when going to certain corner the compensation should be different due to mechanical construction.
If you pay atention to the picture you will realize that reaching point 1 or point 2 is different because the pivoting point is not exactly where the center is, the reason for that was to keep everything well balanced.
So when reaching point 1 the teflon tube was pulling the effector and was trigerring the endstop of z probe while doing bed mesh levelling,
Is it any chance of compensating that via firmware? otherwise i would have to make a complete different system

ander

i can tell you point 1 and point 2 parameters

dc42

The height of the extruder needs to be lower when the effector is at point 1 than it is when the effector is at point 2. You can achieve this by specifying the XY coordinates of the 4th tower (in the M669 command) as being closer to point t than to point 2. I think that to a first approximation, the coordinates of the pivot point may be about right.