major layer gaps and horrible seams - any advice?  

RE: major layer gaps and horrible seams - any advice?

Have you ever changed the PTFE tube in the hot end? They wear out and may clog the hot end. Have you done a cold pull? You can tell when you heat up the nozzle and push manually if it feels clogged. They used to have instructions all on one page but it seems now the instructions are slideshows (boo).

https://help.prusa3d.com/guide/how-to-replace-a-hotend-ptfe-tube-mini-mini_119449

This one is on one page still:

https://help.prusa3d.com/article/cold-pull-mini_126399

What kind of filament and has it been dried? Drying always makes things better with no downside.

Regards,

Mark

RE: major layer gaps and horrible seams - any advice?

thanks Mark! I will inspect the tube in the hot end asap. I've done a few cold pulls and have used a brand new filament roll out of the vacuum sealed bag but neither of those have helped.

RE: major layer gaps and horrible seams - any advice?

Filament may still be wet right out of the bag. I strongly recommend a heated filament drier. I put the rolls I am going to use in for at least a few hours and every overnight if using for more than one day.

When doing a cold pull, it should be possible to push the filament through the hot end with your fingers without that much force, depending on the temperature and filament used. Once you do it when it is working right, you can then detect later when it is clogged by feel. Using the needle to clear any burnt filament pieces from the hot end can't hurt either. I also clean off the nozzle with a wire brush and Xacto after every print. Be careful not to short anything out. A silicone sock helps to keep things clean.

Regards,

Mark

RE:

Also do a typical maintenance check if you have not done it, such as checking if all the screws are not loose, check belt tension, PTFE short and long tube quality ( if not used up or burned), heatbreak/heat block and nozzle position, and if the nozzle needs replacement.

https://help.prusa3d.com/article/regular-maintenance-mini-mini_133222

RE:

Hi I have similar problems with layers. I already done tohose things:

- clean extrusion gears

- check tension of pressure bearing

- check tension of belts

- check PTFE tubes

- change nozzle for a new one

- changed filament

Could it be the problem with wet filament? I just store it in room and don't dry it up.

I'm using Mini+ in Enclosure.

RE: major layer gaps and horrible seams - any advice?

Do a first layer calibration, hard to see on the pic but i think it should be higher.

Iit feels like it is too low now, thus extra filament oozes to the sides and makes other extrusions uneven already. Meanwhile material on the nozzle accumulates until it drops on its own due to mass and drag. This happens especially on change of the direction close to the perimeter. Further layers get also dragged over and the process repeats, making nozzle extrusion uneven in very long distances.

RE: major layer gaps and horrible seams - any advice?

I decided to dry up the PLA filaments in an idustry drier to see, if there is any isssue, but I don't think that helped.

I did fist layer calibration and it didn't really helped. You can see on the calibration print, that there are still some issues with filament extrusion on two places:

I tested it with a print and the issue is there even more to see:

Do you have any idea?

RE: major layer gaps and horrible seams - any advice?

I would look into the extruder if it needs cleanup, also check the tension spring in the extruding mechanism and if the unwinding the spool is not causing any noticeable obstructions (such as filament spool not rolling smoothly).

Also check if the filament is not unevenly eaten during printing - that is start example print, and when it starts to get the issues look how filament is drawn from the spool. Additionally abort the print and retract the filament and check if there are signs that extruder struggled with pulling/pushing filament (some parts on the filament may be more used up then).
Check if the filament does not have visible uneven areas.

RE: major layer gaps and horrible seams - any advice?

I cleaned an extruder a couple of times and checked the spring tension.

After the first layers yesterday I finished the print and it war really ok. So I did another one, where I had a lot of issues last time and it did surprisingly well. I'm experiencing the problems I had before just sometimes on a print:

I was thinking about drawning the filament from the spool as well. I'm not sure if it's a problem but it might be. I use my Mini+ in an Prusa enclosure. The spool hangs on a printed holder:

Enclosure spool holder - complete

It looks like, that there is some friction. What would be better solution? The holder axis isn't revolving but stiff and the spool needs to be pulled with more force to overcome the friction.