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jeremy-gillick

Rats Nest

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A couple nights ago I set the machine to print a custom model, watched the first 30 minutes of printing and went to bed. In the morning it seems that the printer had printed the first 12mm correctly and then at some point the layers stopped sticking (?) and built a rats nest of filament.

Then I changed the settings to print slower and the same thing occurred. Unfortunately this seems to happen after an hour or so of printing, so I haven't been able to stay and watch it to that point. The first print the temperature was 210 degrees and the second print was at 215.

Both times was with a custom profile printing at 0.085 mm/layer. Next I'm going to try using the stock "Normal quality print" option, as a baseline.

Any ideas on why this is happening? From what I've read it sounds like it could be underextrusion, but I would think slower and hotter would have helped that. This is also a temperature that I've printed everything else at.

What I was trying to print

What I was trying to print

 

The rats nest

 

Rats Nest

What printed, with the rats nest removed

What was printing, with the rats nest removed

 

The printing profile

 


[profile]
layer_height = 0.085
wall_thickness = 0.4
retraction_enable = True
solid_layer_thickness = 0.5
fill_density = 15
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
retraction_hop = 0.0
bottom_thickness = 0.3
object_sink = 0.0
overlap_dual = 0.15
travel_speed = 150.0
bottom_layer_speed = 20
infill_speed = 60
inset0_speed = 0.0
insetx_speed = 0.0
cool_min_layer_time = 5
fan_enabled = True
skirt_line_count = 2
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_type = Grid
support_angle = 60
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
[alterations]
start.gcode = ;Sliced at: {day} {date} {time}
;Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}
;Print time: {print_time}
;Filament used: {filament_amount}m {filament_weight}g
;Filament cost: {filament_cost}
;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line
;M109 S{print_temperature} ;Uncomment to add your own temperature line
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
G1 Z15.0 F{travel_speed} ;move the platform down 15mm
G92 E0 ;zero the extruded length
G1 F200 E3 ;extrude 3mm of feed stock
G92 E0 ;zero the extruded length again
G1 F{travel_speed}
;Put printing message on LCD screen
M117 Printing...
end.gcode = ;End GCode
M104 S0 ;extruder heater off
M140 S0 ;heated bed heater off (if you have it)
G91 ;relative positioning
G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+0.5 E-5 X-20 Y-20 F{travel_speed} ;move Z up a bit and retract filament even more
G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way
M84 ;steppers off
G90 ;absolute positioning
start2.gcode = ;Sliced at: {day} {date} {time}
;Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}
;Print time: {print_time}
;Filament used: {filament_amount}m {filament_weight}g
;Filament cost: {filament_cost}
;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line
;M104 S{print_temperature} ;Uncomment to add your own temperature line
;M109 T1 S{print_temperature2} ;Uncomment to add your own temperature line
;M109 T0 S{print_temperature} ;Uncomment to add your own temperature line
G21 ;metric values
G90 ;absolute positioning
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
G1 Z15.0 F{travel_speed} ;move the platform down 15mm
T1 ;Switch to the 2nd extruder
G92 E0 ;zero the extruded length
G1 F200 E10 ;extrude 10mm of feed stock
G92 E0 ;zero the extruded length again
G1 F200 E-{retraction_dual_amount}
T0 ;Switch to the first extruder
G92 E0 ;zero the extruded length
G1 F200 E10 ;extrude 10mm of feed stock
G92 E0 ;zero the extruded length again
G1 F{travel_speed}
;Put printing message on LCD screen
M117 Printing...
end2.gcode = ;End GCode
M104 T0 S0 ;extruder heater off
M104 T1 S0 ;extruder heater off
M140 S0 ;heated bed heater off (if you have it)
G91 ;relative positioning
G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+0.5 E-5 X-20 Y-20 F{travel_speed} ;move Z up a bit and retract filament even more
G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way
M84 ;steppers off
G90 ;absolute positioning
support_start.gcode =
support_end.gcode =
cool_start.gcode =
cool_end.gcode =
replace.csv =
switchextruder.gcode = ;Switch between the current extruder and the next extruder, when printing with multiple extruders.
G92 E0
G1 E-36 F5000
G92 E0
T{extruder}
G1 X{new_x} Y{new_y} Z{new_z} F{travel_speed}
G1 E36 F5000
G92 E0

 

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It's probably skipping part of your model.

Look at the model in cura layer view carefully - especially starting where the problem occurs. Perhaps a wall is too thin to print. Cura will print down to .4, .6 or .8mm wall thickness only. Not sure why there are different limits at different times but the nozzle hole width is .4mm so obviously no thinner than that.

Also look at the part in xray mode - anything the color red is a potential problem.

 

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very nice printed model !

Another little tip is.. I find great success in going into the expert settings in Cura and choosing from the Combine Options A.

David really did a nice job of this function and it saves my bacon all the time.

Ian :-)

 

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This is a typical problem with Sketchup... After some time I learned how to prevent these red surfaces (inside planes or double planes at the same place) already while modelling. Selecting the whole model and using the "smooth edges" command (I don't know if that's translated correctly, I'm using the german version. See screenshot below) will reveal all "double planes" which occur mostly when you're doing very small surfaces. The lines will not disappear if there are double surfaces.

sketchup smoothing

By the way, this smoothing tool doesn't change any geometry, it just makes lines between surfaces disappear, if the angle between the surfaces is less than the angle specified (I leave this at 20°).

I prefer making a clean model over using the "patch-up" tools, because these don't always work as intended. For example, I'm doing parts right now which will have some structures that are entirely enclosed within the part, because I added supports which make it print better, but lead to that effect. Cura will just ignore these inside structures with "fix horrible" activated. But the structures are necessary because you're supposed to remove the support after printing and then they won't be inside structures anymore...

 

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Another little tip is.. I find great success in going into the expert settings in Cura and choosing from the Combine Options A.

 

 

Selecting the whole model and using the "smooth edges" command (I don't know if that's translated correctly, I'm using the german version. See screenshot below) will reveal all "double planes" which occur mostly when you're doing very small surfaces. The lines will not disappear if there are double surfaces.

 

I was wondering what those options were. I'll try those with my model to see. The model currently consists of 3 components, so that I can edit the sides and the base apart from the structure. To solve it yesterday, I exploded all components and removed a bunch of the lines in between them.

 

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