Tevo Little Monster scratches print

Phaedrux

@justus2342 said in Tevo Little Monster scratches print:

Measuring repeatingly one XY-Coordinate yields quite good results. But when moving the effector in XY and then moving it back again it is not that consistent anymore. It seems a little like the Z-height is dependent on the direction of the last move in the XY-plane.

That would definitely indicate backlash. Unfortunately I'm not sure what exactly to check at this point.

justus2342

I managed to solve my Problem. I switched to a Smart Effector, Haydn Huntleys Magballarms and light self-printed carriages (Thingiverse).

Actually the problem is not entirely gone. But it became so faint that it does not really matter at all anymore.

giostark

@justus2342
The frame of this printer is really crap. I'm managing to rebuilt it with a CNC machine for eradicate all the mechanical issues.
Those of the the Tevo really steal nonsense amount of time to so much people. By the way after 2 years on the delta I could build it by my self and it will be !

dc42

@justus2342 said in Tevo Little Monster scratches print:

I managed to solve my Problem. I switched to a Smart Effector, Haydn Huntleys Magballarms and light self-printed carriages (Thingiverse).

Actually the problem is not entirely gone. But it became so faint that it does not really matter at all anymore.

If you haven't already done so, lubricate the magnetic joints with some light grease to reduce the backlash.

giostark

@dc42 said in Tevo Little Monster scratches print:

light grease

With "light grease" What do you mean?

I'm using this grease of Teflub (PTFE) : http://82.185.148.242/B2C/SchedeTecniche/Cat_Generale/Cat_Gen2016_ristampa/CatGen_ristampa016017_15.pdf
Is it good? Or I should use the silicon one instead?

dc42

It probably doesn't matter exactly what lubricant you use, as long as you use one.

justus2342

@giostark Why do you consider the frame "really crap"? What exactly did you change/rebuild with your CNC machine?

giostark

https://forum.duet3d.com/topic/6951/not-yet-solved-tevo-little-monster-duetwifi-errors/139
1)In my case the top frame had holes not aligned with the extrusion holes same as the bottom frame.
2)the 3 extrusion (tower) are bended.
3)bars have different length (six time the maximum allowed)
4)the glass bed is not glued planar in the aluminium socket.
I'll redraw with Freecad the top/bottm frame and some lateral connection for make the build very rigid. (all will be CNC milled)
Also I'll use the 8x2 extrusion for leave the linear rail the right space to be mounted...
I'm building a pretty amazing (for my standard) CoreXY 300ZL and at the same time I'll rebuild my delta.
I'll post all the stuffs here

Manuel

Hello folks,
I'm a real newby in the "world of codes".
Lately i bought a tevo little Monster (occasion) to build some bigger parts i need for my gollowing project.
Now: i had to make several changes to make the printer work again. Additionally a added 3 springs under the bed for manual leveling.
This set the bad heigher than before.
Auto calibration still works with this height of the bed.
BUT now: I'd likd to add a new plate onto the bed. Again 4mm of material.
These 4mm would make the hotend crash into the bed while auto leveling.

What/Where can I change a Z-setting, so this could be fixed?

Thank you very much for your help!

giostark

@manuel
Hi ,
At this page you can find the delta printer calibration full explanation:
https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer

If you are sure about the numbers that you added (thickness of the glass) you can just modify the "System > config-override.g" file in the M665 line at the H parameter (subtracting the mm you added).
If this will go fine you can change the H parameter also in the config.g

In general for see the height of the printer:
1- power on the printer
2- home the printer
3- lower the head till the glass
4- when you are at the zero send in console G92 Z0 (to define the new zero level)
5- home the printer and read the new height value in the duet dashboard (Status > Z position) after the endstop are triggered. Keep in mind that the home position is lowered of 5mm (you can find your value in the homedelta.g , so you have to add also those mm to the height value you read in the Status > Z position.
6- write this new height in the config-override.g (and config.g)

If you dont have changed also the nozzle height modifying the head of the printer , should be enough adjust the height as above.