Under extrusion only on corners?

[Marco117 0]

So I'm trying to print parts for my BB8 build and I'm constantly running into the same problem. What seems to be under extrusion is happening only on the left side of a face. I'm assuming it is where I have an inside angle and Cura makes a join. It looks like it is slow at starting the extrusion but I can't exactly tell. The rest of the piece seems fine but it ONLY seems to be on the left side of a face OR immediately after the nozzle does an internal angle. You should be able to see in the photos.

 

I've tried increasing flow

increasing the "retraction prime amount"

increasing or lowering the extruder temperature

decreasing the outer wall speed

rotating the part 45,90,180 degrees

none of these seem to work or will make the print quality worse.

 

Could someone help me out?

 

Here are my current settings...

 

Layer height 0.3mm

Wall thickness 1.2mm

Wall line count 4

Infill 25%

Nozzle temp 220

Build plate 60

Flow 101%

Print speed 55mm/s

Wall speed 45mm/s

Outer wall speed 30mm/s

Print acceleration 300mm/s

Jerk 25mm/s

Retraction on

No supports

 

Thanks

[gr5 2,094]

What are all your line widths and what is your nozzle width - this is very important.

 

Also what kind of printer is it?

 

Also are you sure it's 300mm/s/s acceleration? That's very slow.  That alone could explain the problem because it would have to slow down A LOT for the corners and sit there and over extrude then slowly build up back speed and underextrude coming out of the corners.

 

It's probably not this but make sure "retract at layer change" is unchecked.

 

I'm thinking it's probably underextruding everywhere it's just worse on this corner.  I would have the machine extrude exactly 100mm and see how far the filament actually moves and maybe change the steps/mm (in other words calibrate the extruder).

 

[Marco117 0]

My line widths are all 0.4mm and I'm printing on the original Creality CR10 with 0.4mm nozzle, I changed the acceleration because I thought it was too much, I decreased it in hopes it would spend longer on the corners as it's under-extruding on the corners themselves too, and just after. I tried changing it back to original speed just now and it didn't make a difference.

"retract at layer change" is unticked.

I'll look into calibrating the extruder

 

Thanks

Edited April 18, 2018 by Marco117

[DarkLinkX5 0]

Any updates on this issue? im dealing with the exact same thing. so identical that the defects look exactly the same.

[gr5 2,094]

Well the issue is moderate to severe underextrusion.  It has many causes.  If you tell me your printer type I'll give you a list of 20 or so possibilities.  The most common across all printers is printing too cold and/or too fast.

[DarkLinkX5 0]

Thanks for your reply and generous help.

i haven't really changed my settings much in the last 5 years.
i got a Prusa i3 mk1 clone back when they were acrylic frames.
I use Cura exclusively but i can try an alternative as a test.

Using part of the setting list above

Layer height 0.3mm
Line width 0.35mm

Wall line count 3

Nozzle temp tried 190, 200, 210

Build plate 50

Flow 120% (100% really bad random under extrusion.)
"V use to print great at these speeds V"

Print speed 80mm/s

Wall speed 40mm/s

Retraction on or off either way it does the same

also on this small test print i cant get this single 0.4 wall to print fully anymore it use to print it fine. all other sides look fine
it looks like its coasting to the corner but that setting is off.

[DarkLinkX5 0]

It must be either Cura itself or one of its settings i randomly tried craftware to slice it and repeiter host to print and it printed without a single hole or under extrusion defect. (slic3r would have probably printed it fine too. same speed setting and even 100% flow instead of 120%) it was a better print than I've seen from Cura in over a year or two.

I tried older version of Cura 3.5 and 3.3.1 and it was better at 100% flow same speeds but still had a tiny gap at the corner about 3 layers high. I would have tried 1.5.4 but it refuses to start last i used that version was about 2 weeks ago because of the split object feature.
Cura likes to start in a random corner and in craftware printed it continuously.
Despite this i still want to fix Cura as its an all in one program. i hate going through 2 programs to print Its completely unnecessary.
if you know any setting i could change to remedy this issue id be happy to get Cura working again.
i have friend who cant use newer version of cura than 3.3.1 because it just seems to go downhill in compatibility. ☹️