1

Topic: x axis

I am getting a shift on the x axis.  I have a Solidoodle 4 and it has performed beautifully up until yesterday.  Now I am getting the offset on every print over about .5" high.  It is okay for a bit then it happens.  I thought I saw something on the forum but I can't find it.  I also can't seem to find a search anywhere.

2 (edited by grob 2014-08-28 22:14:25)

Re: x axis

Shifts happen when the x motor misses steps, or shuts down temporarily.
There are a number of causes, but it sounds from your description (ok for a bit then happens) that it might be the stepper driver overheating, which has been reported here frequently. It's currently winter in my part of the world, but how's your weather??

I'd recommend the following in any case (you should be able to search on the forum for more details of any of them, just use google: "site:soliforum.com tune v ref" for example):
* Make sure the x axis rails are appropriately lubricated (thin layer of lithium grease is well regarded)
* Make sure your driver board is cool / well ventilated - adding a fan of some kind (even a desk fan!) is a good idea
* Tuning V-ref for your x-axis (i.e. adjusting the current through the motor so it runs smoothly - too little current will lead to missed steps, and too much current can overheat the driver leading to thermal shutdowns and shifts)

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

3 (edited by Bookmaker 2014-08-28 23:11:09)

Re: x axis

Thanks grob.  The x motor was my first thought also.  Can you tell me what V-ref is and how to tune?

4 (edited by AZERATE 2014-08-29 00:48:41)

Re: x axis

Use a ceramic or other non-conductive screwdriver to tune the stepper driver. Only instructions I have found all said to "adjust by sound", but with all my fans going (30mm E3D fan seems to break the sound barrier), this is difficult. So I adjusted slightly over a few single walled calibration cubes.

Bare in mind only a TINY turn would produce results. 1/16 of a turn can give a drastic result.
Also, be sure your X belt has an even tension. If it constantly shifts to a specific side, this could be a cause.

Printit Mason and Printit Horizon printers
Multiple SD2s- Bulldog XL, E3D v5/v6/Lite6, Volcano, Hobb Goblin, Titan, .9 motor, Lawsy carriages, direct Y drive, fishing line...the list goes on
Filawinder and Filastruder #1870.....worth every penny!

5

Re: x axis

+1 azerate's advice

Adjusting by sound is quite easy, in fact probably easier and more effective than by voltage as normally instructed. I don't take any responsibility for mucking up your setup, but as long as you use a non-conductive screwdriver to prevent accidental shorts, and you don't leave the thing in max current for extended periods of time, chances of causing any damage are low.

(1) Set the printer moving back and forwards a fair distance (say 50mm) at normal jog speed. You can do this by clicking the manual buttons in R-H, but you run out of hands pretty quick - try writing yourself a little g-code script if you're brave and 'print' it...
(2) Wind the tiny potentiometer right down (counter-clockwise). The motors will stop.
(3) Wind the pot slowly back up (clockwise) and listen. You should hear the following:

* Silent to begin with (no current!)
* Ringing at increasing volume, no movement
* Movement starts, clicking noises and erratic motion
* Motion gets more consistent, clicking gets less frequent and eventually disappears
* Rumbling/grinding noise starts to appear, gradually gets louder, eventually becomes a physical vibration

(4) You want to set it somewhere between the clicking going away and just being able to make out the rumbling noise.

Unplugging fans etc. for a quiet environment helps to make things clear.

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

6

Re: x axis

Great description Grob smile

Printit Industries Model 8.10 fully enclosed CoreXY, Chamber heat
3-SD3's & a Workbench all fully enclosed, RH-Slic3r Win7pro, E3D V6, Volcano & Cyclops Hot End
SSR/500W AC Heated Glass Bed, Linear bearings on SS rods. Direct Drive Y-axis, BulldogXL
Thanks to all for your contributions