[Cura 4.7.1] Gaps always appear in exactly the same spots

[marinus 2]

Okay, this doesn't just happen in Cura 4.7.1 but it's what I'm using, hence the title.

 

Anyway, I am printing on a DIY printer so I hope it's okay I'm posting here. I am using Cura though so I figured this would be the place to be.

 

To explain my issue, I made a video:

 

The holes always appear on the same spots in any model I'm printing, this rules out extruder problems since extruder problems will mostly be intermittent (assumption).

 

I'm printing this in PLA with a 0.5mm nozzle, 0.3mm layer height, 0.465mm layer width.

What I did:

- flow calibration

- retraction + temp + bridging calibration

- all other calibrations that you could possibly think of (including E-steps/mm)

 

I've been tuning the machine for two weeks now and I haven't been able to work this one out. I am able to produce somewhat okay results, even ordered new extruder gears but I think the ones I'm using now are great already.

 

Another issue I'm having is that the top layer on the bottom of for example a vase doesn't adhere that well to the wall that is printed on top of it. Could this be an issue of too much cooling?

 

I'm very familiar with building/hacking machines, but not with solving non-standard issues. Maybe it's an easy fix, I see that Cura has 'fill gaps between walls' options but I am not sure what it does. I already enabled that option but see no improvement. The holes on the bottom part that can be seen in the video are the most important for me to fix. I'm leaning towards maybe tuning retraction a bit to solve the holes but I'm not sure what to do exactly. I hope someone knows!

 

Thanks for your time,

Marinus

 

Update:
I managed to improve the quality a little bit more by changing the retraction from 1.3mm to 1.1mm and retraction speed from 40 to 30mm/s. The prints still don't come out perfectly, but it's a lot better already. Still, I hope someone has tips for the holes especially in the first layer near the screw holes and the gaps in the sides that appear at the same spots.

Edited October 27, 2020 by marinus