Small issues with first prints

[Slynold]

Hello community,
i’m completely new in 3d printing.
I got my SM350 a few weeks ago and already did a few prints.
I started with Luban and printed an adapter (made with tinkercad) for the ventilation hose.
After this i made a few experiments, and now i tried to calibrate my printer like described in this useful post by brent113 Snapmaker 2.0 Initial Calibration Settings / Experiences

At the same time i tried the alternative slicers Simplify3d and Cura and configured them like described in brents post.
After that i printed a benchy with simplify3d high quality settings, and then with the same settings in cura.

It seems that the cura print result is much better when it comes to overhangs, but there are some fine impurites that look like snow on only one side of the benchy. Can you help me get rid of these?
Also i made a few measurements that show that there are irregularities on both prints.

I’m uploading the Photos and the sheet with the measurements in following google drive directory.

Benchy - Google Drive

Thanks in advance

[brent113]

Hi @Slynold! And welcome!

Honestly, nice job, 3DBenchy has some difficult areas, and it looks good.

The “snow” looks like where the nozzle may have started or stopped on a layer and left a small blob. Between that and some of the stringing, which isn’t too bad, maybe double check your retraction settings.

It does look like the finish on the Cura print is better. I appreciate the side-by-side spreadsheet, that’s awesome. I’m wondering if the Cura print was printed at a higher temp, and that’s why it’s shinier? Maybe it’s just the lighting.

It looks like Cura and S3D had slightly different settings as far as speeds go - I’m thinking you should be able to put some of the info from Cura’s settings into S3D, maybe improve that a bit.

The Cura bridging settings I think are easier to use. Maybe add a fan while the front window bridge prints for some extra cooling, or try dropping the S3D bridge speed and flow.

If you make any progress in improving the surface quality and some of the other issues I’d love to hear what you did.

[geburges]

Hi. I am a long time user of Cura. I agree that it looks like you have some minor retraction issues but it also may be that the nozzle is a bit too warm.
How far and how fast are you retracting? What type of filament are you using? Manufacturer? Hot end temp?

[Slynold]

Hey! Thanks for your fast replys

I checked my retraction settings and enabled z hop with a parameter of 0.5 mm and retract at layer change.
Also I set the wipe nozzle parameter to 3mm instead of 0.2

I’m using Eryone white PLA, with a recommended temperature of 210 C°
The retraction distance is 1 mm and 60 mm/s

Now printing a few calibration cubes.

Fun:

Big Daddy Scene

This is what i’m thinking about the meaning of retraction settings

[Slynold]

I uploaded a video of the first cube layer in the shared directory. It looks good, but there’s a strange jerk at the end.

[brent113]

Yeah, that’s the 3mm wipe. It will do that at every retraction. That retraction is because it went from the outside perimeter to start the infill.

That jerk sounds pretty aggressive - you might double check your maximum print speed, or double check your acceleration and jerk settings. It might be fine, but it looks like the machine is starting to shake. You might be on the verge of skipping steps from accelerating too hard.

[Slynold]

Thank you!
Indeed! I figured out that the wipe is a travel move, not a print move. Travel speed was 120 mm/s.
I set it to 40 mm/s now and start a new cube

[brent113]

Just out of curiosity - did you increase the maximum allowed travel speed? I believe by default there’s a firmware limit of 50mm/s.

[Slynold]

No, thus ist something i wouldn’t dare

[Slynold]

I uploaded another Video. Now it sounds like a strange fart.

[brent113]

Haha yes, you’ll learn to love it.

The designers confirmed in another thread the Y carriage and build plate function as a mechanical speaker, and at certain Y travel speeds it resonates and amplifies the sound of the stepper motors. That’s normal.

[Toxic]

resonance like a bass drum

[Slynold]

Ist it possible to calibrate axes after making enough measurements?
It seems that the Y axis is inaccurate.

[brent113]

Inaccurate, how so? Steps/mm? Should be 400.

[Slynold]

I haven’t checked that, and i’ll come to this later.
This issue is hell, but now i found a thread about this problem.
It seems to be an issue with the bed and nozzle heat in combination.

Rough Texture on Lower Rounded-Edges

I’ll post my story later when i tried that

[Slynold]

Alright. I still havent printed a good benchy.

At first:
I have stopped my efforts to use Simplify 3d. It is rather outdated and the developing company is unresponsive. I wanted to give the software back, as promosed on their homepage, but no one answers my refund request. Sadly it lookes like I invested 140$ in riding a dead horse.

I’ll keep on using cura because it is maintained much better.

My problem is still the unclean hull of my benchys. I made several tests and came to the point that its no retraction issue because made some really good retraction towers. Also with the detailed retraction test I found here: http://retractioncalibration.com/

After struggling around with the white PLA from Eryone I changed to the neon orange translucent PLA from Amazon Basics and started some new tests.
It turned out that this Material is better for testing, because of it’s richt in contrast and easy to spot issues.

After doing some research I learned a lot about retraction.
I made a few retraction tests and found the good settings for my material.

Temperatures:
Bed: 60 deg C
Hot end: 205 deg C

Part Cooling: 100% fan from layer 2

Segment | Retraction distance | Retraction speed | Extra restart distance | Unretract speed | Z hop
F | 3 mm | 60 mm/sec | 0 mm | 60 mm/sec | 0 mm
E | 2 mm | 60 mm/sec | 0 mm | 60 mm/sec | 0 mm
D | 1.5 mm | 60 mm/sec | 0 mm | 60 mm/sec | 0 mm
C | 1 mm | 60 mm/sec | 0 mm | 60 mm/sec | 0 mm
B | 0.5 mm | 60 mm/sec | 0 mm | 60 mm/sec | 0 mm
A | 0 mm | 60 mm/sec | 0 mm | 60 mm/sec | 0 mm

Temperatures:
Bed: 60 deg C
Hot end: 205 deg C

Part Cooling: 100% fan from layer 2

ABL: No ABL

Segment | Retraction distance | Retraction speed | Extra restart distance | Unretract speed | Z hop
F | 1.5 mm | 60 mm/sec | 0 mm | 60 mm/sec | 0 mm
E | 1.5 mm | 50 mm/sec | 0 mm | 50 mm/sec | 0 mm
D | 1.5 mm | 40 mm/sec | 0 mm | 40 mm/sec | 0 mm
C | 1 mm | 60 mm/sec | 0 mm | 60 mm/sec | 0 mm
B | 1 mm | 50 mm/sec | 0 mm | 50 mm/sec | 0 mm
A | 1 mm | 40 mm/sec | 0 mm | 40 mm/sec | 0 mm

It looks like a z-hop is not nescessary to tear off the excess filament flow and seems that 1mm and 40mm/sec retraction is okay for now.

After that I reset cura and configured my profiles from scratch.

At first I build a new start gcode to match my needs.

;X - X axis position
;Y - Y axis postion
;E - extruder / filament Position
;F feedrate / speed in mm/s

M104 S{material_print_temperature} T0 ; Set hotend temperature of hotend number 0
M140 S{material_bed_temperature_layer_0} ; Set temperature of bed for first layer
G28 ; Auto home all axes
G90 ; Set to absolute positioning
G1 X330 Y-10 F3000 ; Move down to the outer left front with 3000 mm/s
G1 Z0 F1800 ; Move downwards to Z zero
G92 E0 ; Set extruder postion to 0
M109 S{material_bed_temperature_layer_0} T0 ; Wait for temperature of bed
M190 S{print_bed_temperature} ; Wait for temperature of hotend
G1 E20 F200 ; Output 20mm of filament
G92 E0 ; Set extruder / filament postion to zero.

Afterwards I used the default profile fine as a base to create my own with these different settings.

Quality:
layer_height = 0.08
layer_height_0 = 0.16

Material:
heated bed temperature = 50.0
print temperature = 205.0

I tried several temperature combinations

Travel:
retraction amount = 1.0
retraction_combing_max_distance = 0.1
retraction_combing = noskin
retraction speed = 40.0
travel_avoid_supports = True
z_seam_type = back
z_seam_x = 0
z_seam_y = 0

These are my determined retraction settings. The seam is suboptimal, but while analysing my problem its nice to see where extruding starts.

Speed Settings:
speed_print = 24
acceleration_enabled = True
acceleration_print = 750
acceleration_travel = 1000

I know the snapmaker is slow - I thinks its because it’s build to be powerfull and sturdy enough to mill. Pure 3d printers just need to drag a bit of plastik aound. So the speed settings are acceptable.

Adhesion Settings:
adhesion_type = skirt
skirt_line_count = 4

I the beginning I notized that the orange pla does not ooze so extreme like the white one out of the nozzle while heating up.
I use the skirt because in the first centimeters no filament comes out of the nozzle.
After that the first layer looks good. And well… I like skirts

Extra Settings:
bridge_settings_enabled = True

Slower when printing bridges? Seems legit

I think I know the source of my problem which looks like barnacles on a ship hull.
I think it has to do with temperature.
The layer high is really thin and a thin layer of PLA seems to be very temperature sensitive.
I think the layer on the overhang curls up and on the next round of extruding the nozzle head runs into it and creates the artifacts. These artifacts appear stronger on the side of the benchy facing the x axis, because the other side is exposed to the cooling fan a bit more.

I made several experiments. The following are all with the fully opened enclosure

The white one is an old experiment.
The orange one is from yesterday with the above settings.
The first black line shows is the beginning of the moment where I pointed a ventilator to the bed.
The second black line shows the moment when I lowered the temperature a bit.

This is the other side (X averted) looks better in the middle area.

Here are two other tries with 190° with and 195° without extra fan, the one with the bended edge was made without heated bed and fan, the other one with bed 50° and 195° filament.

So well - both are not nice but one slightly better.

So wanted to know how big the influence of the integrated fan really is so i made one with fan deactivated. I finished the build early

Thats cool: No stringing/retract issues

But the barnacles are still there. They are small, they look a bit wavy. Maybe it’s ringing or ghosting?

At the moment i have now idea how to proceed.
It should be possible to print with this layer height.

Please help…

[brent113]

Is your nozzle partially clogged? If you feed filament manually does it take very little force and it comes out perfectly round and smooth?

[Slynold]

Interesting suggestion. I’ll give it a try in a few minutes

[Slynold]

I made a video. I dont know what means verry little force, but it files like i need some power to press it through the nozzle. My caliper says its not perfectly round.

[Slynold]

PXL_20201026_164457476.LS.mp4 (video)