Possible to print with out Blobs and Zits at 0.2mm?

[BumbleDuck 0]

Hey all,

I'm having a devil of a time trying to calibrate my Ultimaker 3 to print cleanly at 0.2mm. I have had this issue with many different PLA filaments.  I want to print at 0.2mm for speed purposes and I am ok with some lines and striations on the prints. However, I would like to avoid blobs and zits and have done a lot of research on retraction and coasting settings. Unfortunately, nothing that I have tried implementing has worked.

I was wondering if anyone has had successful prints without blobs on their ultimaker 3. And if so if they had any suggestions on what settings they changed to get successful prints, if they had to at all.

I've listed the retraction and coasting settings and my interpretation of them below. Perhaps I am wrong in my assessment of some of these? I apologize if so as I am still a novice though I have tried to do research before posting to the forum.

Retraction

Retraction Distance - The length of material retracted. My understanding is that this should be a high value for clean prints (especially to avoid stringing)

Retraction Speed -  The speed that material is retracted. My understanding is that this should be a high value for clean prints.

Retraction prime speed and extra prime amount - Ok here's where I get a little confused. Cura says that the extra prime amount is an extra amount of filament that's "primed" to compensate for lost material that oozes away in a travel move. This sounds similar to "extra restart distance" from  this guide from simplify3d, which recommends a negative value to stop overpriming as most blobs and zits seem to come from extra filament. Negative values makes the input box yellow, but the print will still slice and print.

Retraction Minimum Travel - The minimum distance of travel needed to perform a retraction. So if I want retractions to happen, this value should be small or 0.

Maximum Retraction Count - Since retraction can lead to grinding issues, this puts a cap on how many retractions can happen in a print. If I want retractions to occur, the largest value without a yellow box is 100.

Minimum Extrusion Distance Window - The window in which the maximum retraction count is enforced. So, in a 1mm window, the maximum amount of retractions possible in that 1mm is whatever the maximum retraction count is set to.

Coasting

Coasting Volume - Cura recommends a value close to the nozzle (0.4mm) cubed (0.064mm^3). If I'm still having issues should I raise or lower this value?

Minimum Volume Before Coasting - The smallest value to be extruded for coasting to kick in. This value should always be larger than the coasting volume, but if I want coasting to happen frequently, this value should be close to to the coasting volume.

Coasting Speed - Speed of coasting compared to extruding, which should be slightly less than normal print speed due to less pressure in bowden tube.

My values for the settings that I think could be related to clean outer walls are as follows.

Quality: Did not change

Layer Height: 0.2, 0.2

Initial Layer Height: 0.27, 0.27

Line Width: 0.35, 0.35

Wall Line Width: 0.5, 0.5

Outer Wall Line Width: 0.5, 0.5

Inner Wall Line Width: 0.3, 0.3

Shell: Not changed

Wall Thickness: 1.2, 1.2

Wall Line Count: 3, 3

Top/Bottom Thickness: 1, 1

Top Thickness: 1, 1

Top Layers: 5, 5

Bottom Thickness: 1, 1

Bottom Layers: 5, 5

Outer Wall Inset: 0, 0

Outer Before Inner Walls: Unchecked, unchecked

Alternate Extra Wall: Checked, checked

Compensate Wall Overlaps: Checked, checked

Z Seam Alignment: Random, Random

Material: (changes)

Printing Temperature: 195, 195

Flow: 100%, 100%

Enable Retraction: Checked

Retraction Distance: 8, 10

Retraction Speed: 25, 45mm/s

Retraction Retract Speed: 25, 45 mm/s

Retraction Prime Speed: 25, 15 mm/s

Retraction Extra Prime Amount: 0, -1 mm^3

Retraction Minimum Travel: 1, 1 mm

Maximum Retraction Count: 25, 100

Minimum Extrusion Distance Window: 8, 1 mm

Speed: (did not change)

Print Speed: 75mm/s

Wall Speed: 54 mm/s

Outer Wall Speed: 38 mm/s

Travel Speed: 250mm/s

Maximum z speed: 0 (default)

Equalize Filament Flow: Checked

Print Acceleartion: 4000mm/s^2

Wall Acceleration: 1000 mm/s^2

Travel Acceleration: 5000 mm/s^2

Enable Jerk Control: Checked

Print Jerk: 25 mm/s

Wall Jerk: 10 mm/s

Outer wall jerk: 5 mm/s

Travel Jerk: 30 mm/s

Experimental: (changed)

Enable Coasting: Checked, Checked

Coasting Volume: , 0.064, 0.075mm^3

Minimum Volume Before Coasting: 0.1mm ^3 0.1mm^3

Coasting Speed: 90, 90

TLDR: What settings do you change to remove blobs and zits on the walls of your prints?

Thank you!

Edited August 23, 2017 by Guest