my delta printer seems to have a mind of its own

[dc42]

@dmkmedia said in my delta printer seems to have a mind of its own:

the auto delta calibration won't touch the bed no matter what I set it I now have my Z set to -5 but it still won't go down. the endstop hit just says yes most of the time.

The fix for that is to increase the H parameter in M558 until you have completed first-time calibration, as recommended at https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer. You could also check the H parameter in your M665 command, which I suspect is much too low.

also, the home all option sometimes works then sometimes find the end stops lowers down then shoots off 20mm or so in one direction.

It sounds like one of the carriages doesn't always reach the endstop. See this bit of the FAQ page https://duet3d.dozuki.com/Wiki/FAQ#Section_When_I_try_to_home_my_printer_sometimes_the_carriage_or_carriages_move_only_part_of_the_way_towards_the_homing_switches_and_I_have_to_command_it_to_home_again_to_make_it_go_all_the_way.

[dmkmedia]

@dc42 said in my delta printer seems to have a mind of its own:

It sounds like one of the carriages doesn't always reach the endstop. See this bit of the FAQ page

they do hit the endstops and i have watched them connect i click go to home repeatedly and it still does it until a turn it off and back on then all is ok. until the next time, it starts to do it
I have now set the M558
M558 P5 R0.5 H30 F1200 T6000
and still it fails to touch the bed on some of the tries here is a video i start at
X,0 Y,0 Z,0
as shown on the video
https://youtu.be/01zD6HJANLA
at 39 seconds is the one where it goes nowhere near the bed

but its totally random the one after this it didn't touch in 3 places

[adavidm]

It might just be a perspective trick, but is the effector level at all times in that video? It looks to me like it's tilting, based on the way the bubble in the spirit level is moving. Are you using the Duet3D PCB magnetic carriage adapters?

Also, difficult to tell in the video, but is the effector registering a hit when it stops in mid-air at 40 seconds?

adavidm

[dc42]

I agree with adavidm, you may be getting a false trigger. When it stops before reaching the bed, does the green LED on the effector flash?

If yes -> false triggering due to too much vibration, or possibly a faulty effector. Please run M350 to check that you are running x16 microstepping with interpolation enabled. From the video, your machine does sound a little noisy when probing, so perhaps you are using lower microstepping, or no interpolation.

If no -> check that the connections between the 8-way connector on the effector and the Duet are sound.

[Danal]

@dmkmedia

The effector IS tilting. It is very clear when the video is played several times. This indicates a problem with the mechanics. Nothing will work until this is cleared up.

Please post a photo of the carriages. There is one very blurry frame where the carriages show... and there seems to be no sign of the carriage adapters. They are the rectangular things in this photo.

[dmkmedia]

@danal said in my delta printer seems to have a mind of its own:

@dmkmedia

The effector IS tilting. It is very clear when the video is played several times. This indicates a problem with the mechanics. Nothing will work until this is cleared up.

Please post a photo of the carriages. There is one very blurry frame where the carriages show... and there seems to be no sign of the carriage adapters. They are the rectangular things in this photo.

They are not fitted as they would not fit to the carriages so I printed one with the measurements on the site with one that would fit

[dmkmedia]

@adavidm it measures a hit when it's sitting still on and off.

[dmkmedia]

@dc42 as per config file above
M350 X16 Y16 Z16 I1
M350 E8 ; Configure microstepping with interpolation

[dmkmedia]

Could it be the tower is too tall at 1000mm

[Danal]

@dmkmedia said in my delta printer seems to have a mind of its own:

Could it be the tower is too tall at 1000mm

I have a working delta with 1500MM towers (that have 1000MM linear slides) and 700mm Hayden Huntley arms. At this instant, that printer is powered off due to the room that it is in being flooded (long story), so I can't easily retrieve the config.

Just wanted you to know that printers that big or bigger do work.

[Danal]

And, I believe you have at least two problems to clear up: False trigger (which others can help you with) and a mechanical problem that is tilting your effector. Until the effector tilt is fixed, nothing else is going to work correctly.

If you measure between a pair of diagonal rods, near the effector, is this the EXACT same as a measure between the rods near the carriage?

Sorry for crappy backlit photos... but they will get the idea across.

[adavidm]

@dmkmedia said in my delta printer seems to have a mind of its own:

They are not fitted as they would not fit to the carriages so I printed one with the measurements on the site with one that would fit

As others have said, it's almost certainly the source of the tilt and you must fix this before going any further. the rod pairs need to be absolutely parallel for the effector to stay level. One of the clever aspects of the Smart Effector design was in using the excellent precision of a manufactured PCB to ensure that the Mag ball holes are perfectly spaced.

If you are getting false readings from the strain gauge on the Smart Effector, that's going to prevent auto calibration from working. Worth double-checking crimps and any other connections, just in case you are getting an intermittent connection fault.

For now, I'd concentrate on the tilt issue. If you can take a clear photo of your carriage mounts, maybe someone can offer advice on how to get the PCB adaptor to fit.

adavidm