[SOLVED] Constant Y-Axis Shift Issue

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Mário Camacho
Posts: 7
Joined: 22 Nov 2015, 21:08

[SOLVED] Constant Y-Axis Shift Issue

Post by Mário Camacho » 11 Apr 2018, 14:34

Good afternoon,

Hope this topic finds you well. In advance, apologies for the "bible" I'm about to write, but I will try describing the issue in the most detailed way possible.

After a few 3-4 months operating pretty well, my Hello Bee Prusa is now completely freaking out at every single print and I have no idea what might be causing it, therefore I decided to seek help. Bear in mind that this printer is brand new, not even a year old.

What happens is, the bed just shifts out of place by about what, maybe 2 cm, always in the same direction (this is constant and is always the same distance so this might give more experienced users an idea of what it could be) and completely ruins the prints. It doesn't happen at the same height (it could either happen for example on layer 6, or on layer 62, that is completely random, but usually happens at any given moment after 3-4 minutes of printing+). I have NOT changed any single setting in the past few months. The settings are equal as to when it was printing well. It happens in EVERY single print, any model.

Not even a small print goes by without the shifting completely ruining it and wasting filament.

- The slicer (Pronterface in this case) shows the object properly, how it should be printed, so I highly doubt it's an exporting or GCode issue.
- At first, I thought it would obviously be that the belt was kind of loose so I tightened it as much as I could. The same thing happens.
- I tightened the pulleys as much as I could aswell. Problem persists.

So, I searched and saw some users (with other printers, but the issue described was similar) suggesting it could be a speed issue.

- I reduced printing speed and at a point even the acceleration on the firmware, but the problem still persists.

I started thinking it could be an overheating issue causing the Y motor to skip steps, but it is NOT a driver overheating - I even put an aditional fan just next to the drivers to clear my doubts, the problem still happened. It is NOT a motor overheating issue as I believe these can go to very high temperatures, but I still noticed it happens even when the motor is still warm or even slightly cold.

I'm starting to think it could only be eletrical.

Any suggestions?

Thanks in advance.

EDIT: I have NOT changed any thing in the printer. Drivers, extruders, motors, belts, everything is original and came with the printer when I received it.

MrDoom
Posts: 223
Joined: 01 Apr 2017, 10:01

Re: Constant Y-Axis Shift Issue

Post by MrDoom » 11 Apr 2018, 17:42

Hello Mario,

Sad to know that your printer is acting out but I think we will be able to fix it.

First of all make sure that your axis are correctly lubed and that you adjusted the stepper driver current (page one of the fixes document download/file.php?id=62), also verify the other items, the stability feet help with frame stability mostly on the Y axis and that can help avoid the problem happening again, once fixed.

From what you described it appears that you Y axis pulley, the teethed piece that attaches the belt to the Y motor, is not tight enough making the axis shift when rotating in the direction with the most resistance, the screws that hold it on the motor shaft should be very very tight. After this test again.

Also another possibility is that the stepper drivers has gone bad due to the use, if the previous fix does not work try changing your X with your Y Axis stepper driver.

A last possibility is that you Y axis bearing, the left side specifically, has lossened up/aged to the point where it binds up on some movements, to test this release the bearings from the printer plate and check if they appear tight on the rails, they should have a small clearance but you should not be able to rotate them in relation to the rail.

Best regard :)

Mário Camacho
Posts: 7
Joined: 22 Nov 2015, 21:08

Re: Constant Y-Axis Shift Issue

Post by Mário Camacho » 02 May 2018, 14:30

Good afternoon,
Apologies for the very late reply but it's been some rough full weeks here. :)

To my surprise it turns out the driver current were in need of an adjustment. Possibly due to the months of use they may have gotten a bit out of 'number' so to speak.

Thanks for the help, I was already out of ideas when I posted :lol:

You may lock this if you wish.
Cheers.

tgala
Posts: 82
Joined: 25 Aug 2015, 14:56

Re: Constant Y-Axis Shift Issue

Post by tgala » 02 May 2018, 16:09

@Mário Camacho, I'm marking this thread as Solved :)
If you wish, you can re-open the thread if the problem happens again. Feel free to open a new thread if something new comes up.

Cheers!

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