First layer problem

[Eldin 0]

Hi,

 

I have a bit of a weird problem. I'm printing loads of the same container, and this went pretty well (for details on settings see below). However yesterday, suddenly the first layer started to get messed up. So I trief what I usually do, rigourously cleaning the build plate and nozzle, level/calibrate the buildplate and apply a thin layer of glue, again, first layer messed up, however, it;s only the left backside of the printer that messe up. The first layer on other parts of the buildplate are fine. Also see enclosed photo's. Just to be sure I printed the same model about 5 times without any trouble before.

 

So I went through a cycle of cleaning and leveling the buildplate about 5 times but with the same result every time. Now I;m avoiding the left side of the printbed but that is not a viable solution. Also while printing on the other side I get more bleeds of fillament during travel. I'm at a loss what I should try. Any hints?

 

Attachments shows the first layer after removing it fronm the print bed. left-under side was neer the front, right top side was near the left back.

 

Thanks!

 

Printer: Ultimaker 2+

Nozzle: 0.4 mm

Layer height 0.2 mm

[geert_2 558]

If it is only in the back corner, and it was not earlier, maybe you could have a look into these:

 

1) Is there something stuck under the glass, so it bends upwards? Sand, dust, a burr around one of the holes in the aluminum plate, or so...?

 

2) Or did the glass itself deform over time? Try rotating it 180° clockwise and see if and in which corner the problem remains?

 

3) In the left back corner, the filament has to make a very tight bending to get through the bowden tube. This may cause a lot of additional friction in the bowden tube. But it may also cause extra friction in the nozzle itself, since the filament enters the nozzle under a different angle, compared to printing in the right-front area (at least on Ultimakers, but this could be different on other brands). When printing hard filaments like PLA, this is an issue on old UM2 printers (non-plus). I don't know if it is also in other models. Disconnect the bowden tube from both ends, and try feeding filament through it *manually*, with the head in various positions (front-left, back-left, center, back-right, front-right), and feel if there is any difference in friction?

 

4) If it is also on other areas: maybe a bad spool of filament, or different brand? Kinks in the filament? Or any other changes in settings (speed, temp)? Or the spool is nearly empty, which adds a lot of "anti-unwinding resistance" to the feeding traject?

 

 

[gr5 2,268]

So the problem is that the nozzle is too far from the glass in that spot.

 

The way tempered glass is made it tends to be higher in the middle although it's usually made at least a meter wide and your slice of glass could be from the edge or the middle but for some reason I think Ultimaker always gets the center slice?  Maybe?

 

Anyway it's very common for the glass to be higher in the center.  Like a mountain in the middle.

 

When you level a mountain at 3 points (rear and front corners) you end up with the rear 2 corners very low.  So there is too much space there.  I would just raise the rear screw a half turn or so (CCW as seen from below).  Or avoid printing in the bad corners because if you raise the rear too much then the center of the glass will be too high.

 

The reason it was better before is because whatever leveling you had done before, you had that corner a little higher in the past.