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battzilla

PICTURES: Having issues with parts, what is causing this??

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Ok.. so got over some issues of my extruder skipping, and now this!

(In order of when they were made, from left first to right last)

1939864_10202363051741046_1868849720544802943_n_zpsd2c464fd.jpg

10325297_10202363051621043_3278254718848032605_n_zpsded14c1d.jpg

I installed a new nozzle, would this be whats causing the issue? I had black filament in there last week, which burned up causing clogs, so I ended up returning it and replacing the nozzle and switching back to white.

Dond mind the black mark on the first part, it was me marking it with a marker. But the other do have some dark spots. Im thinking it needs to cycle more filament??

Here are the setting for my UM1:

Untitled_zps9e30d2f2.jpg

Ultimakersettings_zps4dba7585.jpg

The part is 25mmx20mmx4mm with a fillet on the front 2 corners. Just a test part..

Should I be changing something up?? How do my setting look? I am printing another part, should be done in about 20 mins.

 

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It looks like Z axis issues. What happens is the Z axis moves too little (gets a bit stuck) and then you get overextrusion because even though you request .1mm layer height it moves say only .05mm so you get 2x overextrusion and it sticks out and makes a line that sticks out. Then a few layers later it catches up and does .15mm instead of .1mm so you get 33% underextrusion on that layer. This repeats randomly.

(by the way your pictures are hard to see the settings - I think it's .1mm but the numbers are only 3 pixels high so it's hard to tell).

Usually this is caused by a loose Z nut. When the Z screw rotates, the nut sometimes rotates also such that the bed doesn't go down at all. Or the nut rotates half as much as the screw. Then for the next few layers the nut doesn't move and they are fine, then it moves again and you get another overextrusion. When you home, the nut spins back the other way ready to mess up the next part.

I would take apart the bed - remove the vertical rods out the top, remove the z screw out the top. Disassemble the entire bed enough to get at the Z screw and see if you can make it so it won't rotate. then put it all back together again. My Z nut is locked in tight and never ever moves. This is not the normal design - the normal design allows it to slide around a little but it should definitely not rotate. I prefer my (minor) modification where the Z screw is locked in place permanently.

 

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It looks like Z axis issues. What happens is the Z axis moves too little (gets a bit stuck) and then you get overextrusion because even though you request .1mm layer height it moves say only .05mm so you get 2x overextrusion and it sticks out and makes a line that sticks out. Then a few layers later it catches up and does .15mm instead of .1mm so you get 33% underextrusion on that layer. This repeats randomly.

(by the way your pictures are hard to see the settings - I think it's .1mm but the numbers are only 3 pixels high so it's hard to tell).

Usually this is caused by a loose Z nut. When the Z screw rotates, the nut sometimes rotates also such that the bed doesn't go down at all. Or the nut rotates half as much as the screw. Then for the next few layers the nut doesn't move and they are fine, then it moves again and you get another overextrusion. When you home, the nut spins back the other way ready to mess up the next part.

I would take apart the bed - remove the vertical rods out the top, remove the z screw out the top. Disassemble the entire bed enough to get at the Z screw and see if you can make it so it won't rotate. then put it all back together again. My Z nut is locked in tight and never ever moves. This is not the normal design - the normal design allows it to slide around a little but it should definitely not rotate. I prefer my (minor) modification where the Z screw is locked in place permanently.

 

I got a shimmy to stick in there so the nut would not move... The problem did not go away :/ Im thinking i have extruder issues or possibly something in the hot end. Because, something it goes a full 2-3 layers without extruding very well and it comes out lumpy. so not sure whats goig on..

 

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It has to be Z. If it were the feeder/extruder it would not alway start and stop when changing layers. For example all the lines that "stick out" go all the way across - none start half way. Most artifacts are very thin - they only occur for one layer. It seems extremely unlikely that your over/under extrusion would always start on layer change and not other random places throughout the part.

I don't know what is wrong with your Z axis but - something is. Did you put any of that green grease on it?

With power to Z off, (or the whole machine off) did you try spinning that coupler at the base of the Z screw and feel if there is friction? You could control the Z axis through USB and command it to different locations and measure it but the amount of error is tiny - on the order of .05mm. I'm not sure if you can measure that very easily.

Is there a cable running from the bed? Do you have heated bed? Is something else rubbing the bed somewhere? Could the coupler at the base of the Z screw be loose? Move the bed down about 50mm from top and then lift up on the z screw and bed to see if it pops out of the coupler.

 

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