Jump to content
Ultimaker Community of 3D Printing Experts
Sign in to follow this  
fabskill

First Layer problem & shrinking

Recommended Posts

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 :

 

Photo 26.02.14 21 06 54

Photo 26.02.14 21 07 41

Photo 26.02.14 08 56 48

Photo 26.02.14 08 56 33

 

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: )

 

 

Share this post


Link to post
Share on other sites

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.

 

Share this post


Link to post
Share on other sites

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 :

Photo 25.02.14 20 03 16

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 :-|

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Our picks

    • Taking Advantage of DfAM
      This is a statement that’s often made about AM/3DP. I'll focus on the way DfAM can take advantage of some of the unique capabilities that AM and 3DP have to offer. I personally think that the use of AM/3DP for light-weighting is one of it’s most exciting possibilities and one that could play a key part in the sustainability of design and manufacturing in the future.
        • Like
      • 3 replies
×

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!