Prints not sticking to bed or just not extruding?

Question

I'm very new to 3D printing. When my printer was new, I got loads of really good prints, however, now they're all failing.

I suspected that the nozzle was in bad shape, so I replaced it, but even now, the prints are still quite bad.

I suspect that the filament is not coming out properly. (extruding?)

I have a Creality Ender CR6 SE. and I'm using Overture Matte White PLA. I've tried using the default 200 °C nozzle and 60 °C print bed temperatures and I've also tried on the upper end of the recommended temperatures at 230 °C and 70 °C.

I've also tried reducing the print speed to 70 %.

Here is a picture of the first layer of a raft:

And here's a picture of a few layers in (still of the raft):

Just before this print I did an auto-level and cleaned the printbed with warm soapy water.

This is the print if I leave it going:

Additional Info: I used the auto-level feature on the CR 6 SE before any of the pictures and used Cura Slicer for slicing.

When using the hairspray method, I managed to get a print out - that print is a 3D Benchy:

Not looking too good. Also - as you can see, I used a different filament.

Using the hairspray again, I tried printing this:

But ended up with this:

UPDATE 3

Ok, So I've found something that's probably not a good thing and I need some advice on it. I think the problem is with the print bed. I found that it can wobble. If I put slight pressure on the front of the bed, the front goes down and the back goes up. Not by much, but there's definite give.

When I print a big circle, the left of the circle is "thinner" than it should be, unless I push down slightly on the print bed. If I do that, then the print thickness on that part of the bed seems to be correct.

However, if I keep that pressure while the nozzle goes around then the print loses adhesion. As soon as I release the pressure and the print bed goes back to what it was, then the print regains adhesion (on that side).

However, if I leave it like that, then the nozzle will be too close to the bed on the other side again.

Now I know. This is a tramming (leveling - are these words completely synonymous?) issue, but when I paid extra for the auto-leveling with the Ender CR6 SE, I paid that extra so that I wouldn't need to mess around with stuff like this. Is this money wasted?

Print nozzle too close on the left, too far on the right:

Should I contact Creality and try to return the printer and get a cheaper one that I'm going to have to manually level/tram anyway?

Answer 1

The CR-6 SE uses strain gauge based sensing for the auto leveling. This implies that the nozzle itself is the probe for the leveling procedure. It is important that there is no filament left on the nozzle and no debris is on the bed (of so, this causes incorrect measurement of the bed surface and results in a too large of a gap between the nozzle and the bed).

Normally, when you replace a nozzle, you need to re-assess the distance between the nozzle and bed with the so-called "paper thickness" method.

This video of the CR-6 shows that paper is still required:

As seen from the first layer of the raft (which by the way is totally unnecessary for PLA) the nozzle is too far from the bed, you see this in balling up of filament and cutting corners where filament is dragged and not deposited. The video does show that it is required to set the Z-offset to the correct value during the printing of the first layer. It is advisable to decrease the Z-offset, alternatively you can set a Z-offset in the slicer, e.g. Ultimaker Cura has a plugin called Z-offset made by Fieldofview to set a different offset directly as slicer option.

You may also have an adhesion problem, probably caused by the incorrect distance, but an adhesive might be beneficial too.

Reprint and post a question on the quality of the print.

Answer 2

It almost looks like that nozzle is too far away from the bed. Try releveling your bed.

Answer 3

I'd be inclined to blame the filament. So my first troubleshooting measure would be to use another filament. If the problem persisted then I'd check all the belts are tight and give the printer a clean with some canned air.

This is assuming your levelling and settings are the same as when it was working ok. Not sure about this assumption because it does look as if your levelling is off for the first layer.