Its on 3 out of 4 corners. What i think it may be is when it first starts it does some random bits of the first layer really fast and the head just moves around really quickly and nothing sticks, then it starts printing normally will some plastic on the nozzle which causes these problems.
Why does the printer do these random bits first? I'm printing the bottom layer at 15 but it looks like the first part is around 40. Hope someone can help:)
Its on 3 out of 4 corners. What i think it may be is when it first starts it does some random bits of the first layer really fast and the head just moves around really quickly and nothing sticks,
That usually means the head is too far from the glass. This is going to be a tricky print but you can see if it's going wrong on the bottom layer and cancel it and run it over and over until it's good. You need to stop using the normal leveling procedure because you need an accuracy much higher than that can achieve.
Start by moving the nozzle closer to the bed - try turning the 3 screws the same amount before you start your print (in other words assume it is level but not at the right height). Practice in your head a few times - if filament isn't sticking or not being squished into the glass you want bed higher so rotate 3 screws counter clockwise as seen from below. Do about 1/4 turn at a time but do a half turn before your start this phone case.
If it's squished too much (so badly that the traces are almost invisible or wider than .4mm traces (.5mm is probably fine) or if the feeder is making that click noise where it skips backwards because pressure is too high and then stops extruding for a few traces - then you need to go the other way (move glass down from head so clockwise).
Then you have to get more complicated if some corners are perfect but other corners are off. But do it all with the screws.
Normally it's best to do a .3mm bottom layer and I recommend that for this print but you can get even better results - really perfect bottom - with .1mm bottom layer. But you will need to get the glass height 3X more accurate! Practice getting a perfect phone case with .3mm before you move on to the much-more-difficult .1mm bottom layer.
Also, set the Skirt (Expert settings) to 2 or 3, so any startup glitches happen in the skirt, not the print.
Thanks for the replies! appreciate it!
Does anyone have an answer why it starts off really quickly? its only for the first 15 seconds of the print, but then i have to pause it clean everything off the nozzle and if anything actually stuck to the bed, then play it again and it prints normally.
Just a few ideas
You say you print at 0.06, but it would be interesting to know the first layer height. Small layers are much harder to make them 'stick', specially if you ain't using glue on the hot bed. A larger height for the first layer helps quite a bit.
Also you print 0.06 at 215C at 15mm/s. At that layer and speed you (I think) could print much much cooler. Probably 190C. You could make the first layer at 215C 0.15 height (if you need to stay as much thin as posible) and then change to 190C at 0.06 height (rough numbers that would need test).
The think you explain about first lines going 'faster'? Maybe it's because the skirt speed it's from the 'print speed' and maybe you had a outlines speed lower. If you wan't all to go at the same speed set the advanced speed for each outline,base layer, etc at 0, then cura (if that's what you use) will use the default printing speed you set.
If you don't use a skirt, try to enable it also, it helps because when printing without it sometimes the first contact with the bed isn't perfect and it might loose stickyness.
Also, try to calibrate really really nice if you wan't to print at 0.06 first layer. Get a feller gauge. The thinner the first layer the better the calibration must be.
Thanks for the reply! One of the issues is i am just terrible at leveling the bed, as i don't really know what signs i'm looking for but i think i've got it alright, however all corners are leveled but about half way down the right side the lines are coming out really jagged?
Also i hear my extruder clicking, when it does this, material doesn't stick for a few seconds and it builds up by the head?
my initial layer thickness is 0.3
initial layer line width is 100%
shell thickness is 0.8 .
Yes i can drop the temperature to 205 after the first layer, i could do a bit more probably but the filament looks the best at this temperature, but its just getting this first layer down clean, then its all good!
Thanks for the reply! appreciate it
Motor click = Motor can't push enough filament = under extrusion
Check this great repost of @gr5 about that, he covers all bases
https://ultimaker.com/en/community/view/17040-um2-under-extrusion-problem#reply-115389
Edited by gr5I tightened my nozzle with the 4 screw things quite tight today? could that really cause a problem?
also the long belt on the back, the half where the pulley is, is fine, but the bottom part is really loose, can that cause a problem?
Thank you!
I know more about umo+ than um2. But that's not the problem since the big difference it's the head. I would suggest that you make photos of what you mean. The short belt of the x motor (bottom to the right) can be tightened and the other y motor short belt (it's on the bottom to the left). But I would follow each step from that link before touching anything else. It's better to go one by one to locate the problem than touching all at the same time. Try printing a box 20x20x20 with each change and lets see how it goes.
Now that I think off. The motor noise IF it's only on the first layer can be because the nozzle it's too close to the bed (increasing preassure and making the motor skip).
1st Calibration:
Okay i had a nozzle jam which sorted most of the problems, however when printing this particular case, the first 15 seconds it just randomly does bits really fast which doesn't stick and just leaves a mess, don't know how to sort it :(
Sometimes I use gluestick to get the first layer to stick, after that things work themselves out, even with Pla and a heated bed
Worth a try!!!
Sometimes I use gluestick to get the first layer to stick, after that things work themselves out, even with Pla and a heated bed
Worth a try!!!
Already am:( thanks for the suggestion!
Still have my belt problem though, the belt on the back (the long one) is really lose, and the one on the right hand side (long one) is slightly lose as well. How can i tighten these?
Thanks!
That in theory on a um2 shouldn't happen since it has springs inside the sideblocks to keep the tension. If isn't a year old machine I would contact support with a video showing the slack of the belts and ask them their output.
Sometimes I use gluestick to get the first layer to stick, after that things work themselves out, even with Pla and a heated bed
Worth a try!!!
Already am:( thanks for the suggestion!
Still have my belt problem though, the belt on the back (the long one) is really lose, and the one on the right hand side (long one) is slightly lose as well. How can i tighten these?
Thanks!
To tighten it you undo all the pulleys on that side to allow the spring tensioner to pull it tight again.
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neotko 1,417
Since its located on a corner I would calibrate the bed.
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