First Layer problem & shrinking

[fabskill 0]

Hi :grin:

 

I need some expert advice...

 

its the first week with my UM2 & i try to improve the quality of some test print...

there is some "gap" problem at some place in the first layer as you can see in the photos :

 

 

Maybe a bed leveling issue ? :/

 

 

at the begining of each print i reduce the speed to 20mm/s for the first layer & set the temperature between 230-240°.

 

i have read that for reduce the shriking i need to low the temperature...i will test that but before i want to avoid the "gap" problem.

 

what's the best retraction setting for this kind of job ?

 

it seems difficult to have a completely clean flat surface for the first layer :???:

 

here's my setting :

 

 

layer_height = 0.1

wall_thickness = 0.4

retraction_enable = True

solid_layer_thickness = 0.6

fill_density = 20

nozzle_size = 0.4

print_speed = 50

print_temperature = 220

print_temperature2 = 0

print_temperature3 = 0

print_temperature4 = 0

print_bed_temperature = 70

support = None

platform_adhesion = None

support_dual_extrusion = Both

wipe_tower = False

wipe_tower_volume = 15

ooze_shield = False

filament_diameter = 2.85

filament_diameter2 = 0

filament_diameter3 = 0

filament_diameter4 = 0

filament_flow = 100.0

retraction_speed = 40.0

retraction_amount = 4.5

retraction_dual_amount = 16.5

retraction_min_travel = 1.5

retraction_combing = True

retraction_minimal_extrusion = 0.02

bottom_thickness = 0.2

object_sink = 0

overlap_dual = 0.15

travel_speed = 200

bottom_layer_speed = 20

infill_speed = 0.0

cool_min_layer_time = 5

fan_enabled = True

skirt_line_count = 0

skirt_gap = 3.0

skirt_minimal_length = 150.0

fan_full_height = 0.5

fan_speed = 100

fan_speed_max = 100

cool_min_feedrate = 10

cool_head_lift = False

solid_top = True

solid_bottom = True

fill_overlap = 15

support_fill_rate = 15

support_xy_distance = 0.7

support_z_distance = 0.15

spiralize = False

brim_line_count = 20

raft_margin = 5

raft_line_spacing = 1.0

raft_base_thickness = 0.3

raft_base_linewidth = 0.7

raft_interface_thickness = 0.2

raft_interface_linewidth = 0.2

fix_horrible_union_all_type_a = True

fix_horrible_union_all_type_b = False

fix_horrible_use_open_bits = False

fix_horrible_extensive_stitching = False

plugin_config =

object_center_x = -1

object_center_y = -1

 

thanks in advance

 

(sorry for my bad english, i am swiss :eek: )

 

 

[gr5 2,178]

It looks like underextrusion caused by the extruder missing steps. This is very common on the first layer.

The extruder motor has a low amount of electric current going to it (on purpose) so that if the pressure gets too high (about 5Kg) it skips back a bit instead of grinding the plastic to powder.

This only happens on the first layer (likely) because your levelling isn't perfect. Your first layer is probably about 20 to 50% too close.

Most people take care of this by printing the first layer thicker - e.g. .3mm. You have it set to .2mm which is already thicker than your remaining layer height - good start.

I would re-level your bed but level it slightly higher (.05mm higher).

Alternatively you could reduce flow for the first layer to about 70% and then put back on 100% for the second layer.

When you print it's good to watch the extruder motor turning - when it skips it makes a distinctive sound - similar to the sound when you change Z to the next layer - but different.

 

[gr5 2,178]

I don't see the "gap" in the red photos.

Did you print a skirt around this part? I recommend at least 1 complete skirt to get the filament to start flowing correctly.

 

[gr5 2,178]

First Layer problem & shrinking

What is the "shrinking" problem?

 

[fabskill 0]

I don't see the "gap" in the red photos.

Did you print a skirt around this part? I recommend at least 1 complete skirt to get the filament to start flowing correctly.

we do not see him too much because the other layer is partially clog the hole:

here is it is during the first layer :

Yes i use the skirt option for the pink one, but i have disable it for the green because it made a diagonal line in the middle of the cover.

What is the "shrinking" problem?

the kind of small "hair" due to the retraction I presume :-|

 

[fabskill 0]

YES !

i have re-level the bed via the maintenance menu & now the first layer run smootly flat & good

Thx gr5

 

[IRobertI 520]

Just out of curiosity, did you level it to come closer to the nozzle or further away? To me it looks like the bed was too far away from the nozzle, not too close.

 

[fabskill 0]

i dont know... i think it was further away from the nozzle, i have just re-lunch the bed-leveling guide from the start but this time I bring the nozzle a little closer to the paper.

definitely cleaner !

Fabio

 

[atelier522 0]

This post could (still) be useful if the photos were still there.

 

Unfortunately, all of the originally posted photos are missing.

Edited September 21, 2022 by atelier522

[MariMakes 198]

Hey @atelier522 welcome to the Ultimaker Community. 🎉
This is post is 8 years old, these must have gotten lost in the migration to a new platform. 

If you are running into any problems and need help troubleshooting.

I encourage you to create a new post and we can try to help us as best as we can.