Added new extruder and now prints shifting ?

[ian 32]

I down powered my motors a few weeks ago because they were burning up.

every thing was running ok, no real problems.

then yesterday, i added my new extruder upgrade, did nothing else to my ultimaker.

printed a big house model over night.

About half way through, the complete building print postion shifted forwards towards the front of the printer 15mm.

massive shift.

then later today i printed another model test and the model still shifted massivly every 10 minutes, always forwards, between 5 to 10mm

i added belt tighteners to the printer and retightened the two short belts. so all belts are now nice and tight.

printed again... still my buildings are shifting in one big move at a time... 10 minutes perfect and then the complete print are shifts 10mm forwards.

any ideas ??

Coulc the motors be now underpowered and i have to rise the voltage ?

or are the belts some how sliding ?

Thanks guys.

Ian

[IRobertI 520]

I'd turn them up a bit. I think I remember you saying that your motors were completely cool after you turned them down? Stepper motors do get hot and that's completely normal and expected. I seem to remember seeing that 85C is a quite common rating on stepper motors. So, if you can still touch the motor without getting scorched I think you're just fine. Of course there's no reason to run them hotter than necessary though.

[Daid 306]

Possible causes:

- Motor power

- Dirty rods that need oil (worked wonders for my machine after lots of moving)

- Axes are not square (was the problem with most machines that came back from NY makerfair)

- Small belts are jumping over pullies, but you'll get bad prints before this.

- A Tesla-coil on the same power strip.

[ian 32]

thanks guys.

i upped the motors a little..

they were running before super cool but i also see no big harm in running them a little warm.

So now im reprinting the same model with the engines running warmer and see what happens...

thanks for all the tips. i think i will oil up both my utimaker this week.

Also can I ask, how do the axis get out of aligment ?

I thought when the frame of the ultimaker is good and tight, that there should be no real movement... ie..

if the rods go into the wholes, the position of the axis should be correct `?

Ian

[snowygrouch 1]

The motors CAN do 80 deg C. But this is usually rated as an acceptable peak value, recommended

long term operating temps are about 50C.

If you are worried about it, I would buy some adhesive temp-strips, and put on the motors. That way

you can see exactly what you have, which is a bit more comforting than discussing for hours about what

"hot or warm" feels like, not very quantifiable....

http://www.grainger.com/Grainger/THERMA ... vc=IDPRRZ1

Or just put fans on them all, and then run whatever current you want and you will never have to worry....

C.

[billdempsey 0]

One more idea for shifted prints. Mine were doing that and I loosened then tightened the pulleys on the X Y motors. That stopped the shifting for me.

[ian 32]

Thanks guys !! :-)

In the end i found, i turned down the motors a little and cleaned that green jelly stuff that i had so cleverly applied to all the axis... yes i win a prize for stupdity... any way, cleaned that crap off and then applied fine maschine oil.

worked like a treat !

Ian :-)