UMO printing head moving randomly

[spiruline 2]

Hello,

I have had my UMO for almost 4 years and use it intensively. It was working very well until recently.

The problem is that after very few correct layers the printing head moves away 5-10 millimeters and keeps trying to print where it shouldn't. After it moves a little It keeps moving away from where it should be printing. It moves away from the print in both axes X and Y, In the photo below you can see the printing head trying to print about 5-6 cm from where it should be.

I have checked all the pulleys which are tight on their axels. I have added belt tensioners and both the short and long belts have good tension. The guiding rods for the printing head are all properly tightened.

I have check all the mechanical parts and everything seems to be OK.

What else could be going wrong? Can both motors (X and Y) be malfunctioning at the same time?

Or could it be an electronic problem? maybe motor controllers? What should I check?

I have never changed the belts. But they have good tension and they don't slip even if I lock the motor axle and apply moving force to the print head.

Sorry about the bad photo, but it's just to show how much the printing head has drifted from where it should be.

I really need some help with this, as the printer is totally useless now. I have a UM2 and UM2+ too, but I need to use this UMO as well

[peggyb 169]

it could have something to do with the temperature of the electronics board. Is the fan running underneath at your electronics?

[spiruline 2]

That's one of the thinks I was thinking about. The fan is working BUT, it used to be very noisy, specially the first minuted after turning the printer on, and now it doesn't make that much noise anymore, although I feel it is spinning. The fan noise stopped around the the time the problems started, so it could be related.

How heat could be affecting this random movements?

The damage doesn't seem to be permanent, as the first few layers (a couple of them) are correct.

Should I try to change just the fan, or anything else should be changed? how could I test if it is really a heat problem?

[Torgeir 212]

Hi spiruline,

Check your power supply, the power supply is one of the units that’s work "hardest" in the printer. If the voltage drops down, your fans will suffer so will the steppers, but the processor will still works as it use own regulator delivering 5 volt DC as long the input (your 12 V DC supply) is more than approx 7.5 volt DC.

Just my 2 c.

Thanks.

Torgeir.

[spiruline 2]

Thank you for that answers. The power supply is delivering a good 19.5 v. I am going to see what happens with a new fan. Is it a 12v fan? I removed the sticker in mine to lubricate the axle and I don't remember the voltage

[peggyb 169]

the fan also collects a lot of dust, cleaning might help a bit, maybe?

[spiruline 2]

Thanks a lot peggyb, I have tried with a friend's printer fan and it works, so problem solved ! amazing how temperature increase can have such an impact. Any technical explanation?

[peggyb 169]

the steppers drivers on the board are getting too hot and loose steps. Normally if the fan doesn't work at all it turns up in the first or second layer already.

[spiruline 2]

Thank you. Good to know. It all makes sense now !

When the printer was cold I could print a 2 x 2 cm test cube. Once it was warm it will fail after a couple of layers. I hope it helps other users.

[Torgeir 212]

Great diagnostic!

Torgeir.