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pimples and tiny loops oh my!


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Posted · pimples and tiny loops oh my!

i have developed tiny bumps and some tiny loops on my prints.

I dont know wher this came from my print were very clean before.

my firmwre has not changed. i upgraded to the lastest version of cura 14.07

i print from sd with my lcd screen.

using .35 nozzle

this is what i normally print like


Quad copter arm.

Phone case.

and now this is my problem

Bumps on legs

loops on sword.

well here is my profile for cura let me know id you see something off.

layer_height = 0.1

wall_thickness = .5

retraction_enable = True

solid_layer_thickness = 0.5

fill_density = 50

nozzle_size = 0.35

print_speed = 50

print_temperature = 235

print_temperature2 = 0

print_temperature3 = 0

print_temperature4 = 0

print_bed_temperature = 60

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 = 3.5

retraction_dual_amount = 16.5

retraction_min_travel = 1.5

retraction_combing = True

retraction_minimal_extrusion = 0.02

retraction_hop = 0.0

bottom_thickness = 0.25

layer0_width_factor = 100

object_sink = 0.0

overlap_dual = 0.15

travel_speed = 60

bottom_layer_speed = 20

infill_speed = 50

inset0_speed = 25

insetx_speed = 25

cool_min_layer_time = 7

fan_enabled = True

skirt_line_count = 1

skirt_gap = 3.0

skirt_minimal_length = 150.0

fan_full_height = 0.5

fan_speed = 0

fan_speed_max = 0

cool_min_feedrate = 10

cool_head_lift = False

solid_top = True

solid_bottom = True

fill_overlap = 15

support_type = Grid

support_angle = 60

support_fill_rate = 15

support_xy_distance = 0.7

support_z_distance = 0.15

spiralize = False

simple_mode = False

brim_line_count = 10

raft_margin = 5.0

raft_line_spacing = 3.0

raft_base_thickness = 0.3

raft_base_linewidth = 1.0

raft_interface_thickness = 0.27

raft_interface_linewidth = 0.4

raft_airgap = 0.22

raft_surface_layers = 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 = (lp1


object_center_x = -1

object_center_y = -1




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    Posted · pimples and tiny loops oh my!


    Maybe print slower and cooler? I would get down to 220°c or less and 30mm/s to 40mm/s for this kind of print.

    And another thing (not sure if it has something to do) but it's recommended to have the wall thickness as a multiplier of your nozzle size so for you 0.35mm, 0.7mm etc ... (not 0.5mm)


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    Posted · pimples and tiny loops oh my!

    Do you really have a .35 nozzle? Stock nozzle is .4mm. I agree with didier. In order of importance:

    1) Slow to 35mm/sec or even 20mm/sec for absolute highest quality.

    2) Lower to 210C or even 200C if you go 20mm/sec

    3) Shell thickness needs to be multiple of nozzle to get good quality. Also 2 passes comes out much better so do .7mm shell/wall thickness.

    4) Increase travel speed to 150mm/sec or even 300mm/sec. The faster the better to break the strings and decrease the time where the nozzle isn't extruding. The biggest problem with Ultimaker is it doesn't print as well when you speed up or slow down the printing and during travel the extruder is stopped yet you still get some slow leakage. So minimize this by speeding up travel time.

    5) Set infill speed to 0 so that it matches shell speed. With 2 passes on the shell this isn't critical because extrusion flow has time to adjust while printing the inner shell. In other words this setting might not affect quality.

    6) Retraction should be 4.5 if the bowden is not moving at all on either end. If it moves when you pull up on it at the head then this should be even higher - perhaps 5.5. This setting affects stringing and you aren't getting any so it probably doesn't matter on this part. That loop on the leg is something else - possibly slow travel speed problem.

    7) Fill density=50 seems very very high. I think you will find that 24% is plenty and it prints much faster at 24% than 25%. Again this doesn't hurt quality - just makes it print slower if at 50%.

    8) You should print with a brim (drop down in basic settings). I assume your parts aren't falling off the bed but still - without a brim you are asking for trouble (parts get knocked off bed).


    retraction_min_travel = 1.5

    retraction_minimal_extrusion = 0.02


    I would set those to zero. There's a small chance the minimal_extrusion parameter caused that loop on the leg. It might not have retracted because it didn't print .02mm worth of filament (which is something like 4mm printing travel).


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    Posted · pimples and tiny loops oh my!

    yes i i do have .35 i build my prusa so it's not an ultimaker i don't have bowen.

    i dont need brim my prints are glass are rock solid.

    that was slowed down i had it a twice the speed. but i will try even slower... i think you may be right about the wall .7

    the reason i had temp high was because i was printing abs.

    as far as retraction i get no blob or drips.



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    Posted · pimples and tiny loops oh my!

    Oh. Then 235 should be fine. And you shouldn't need nearly as much retraction as I said.

    Even on a prusa you should be able to set travel speed higher. Probably at least 150mm/sec. Marlin can only send so many steps per second as the cpu gets tied up. On the UM that's about 300mm/sec on X and Y simultaneously. But you might have more steps/mm on your axes. I really don't know.

    There shouldn't be a speed limitation on prusa mechanics - it's more of an acceleration limitation. Because UM has such a light weight head it can do 5000 mm/sec/sec right out of the box and much higher if you tune it up good. Prusa I'm sure has lower acceleration but should have no trouble with fast *speeds*.


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