printing problem caused by stl wall thickness?

Hey,

Having a problem printing a 40mm fan mount that I am making in autocad. The thing is when I print a solid object and select the amount of layers (vertical shells) in slicer that works fine but what if you want to alter the thickness for different parts within the STL it seems to give me issues in the example here I made the wall thickness of the hollow cylinder 1mm and for some reason it seems to be extruding too much plastic and the nozzle is dragging through causing this ugly part.
As you can see my parts printed with a solid unhollowed stl is no problem 1 wall and 2 wall shown no flaws and are the correct thickness around 0.5mm for the 1 wall and the 2 walled one is actually around 1.15mm about right I guess.
Anyone can shed some light on this?



thanks

Edited 1 time(s). Last edit at 04/13/2013 01:03PM by dave584.

Is your extruder calibrated? Meaning if you tell it to extrude 100mm that's what it does. If not that is a problem that will have problems for all your parts. Also depending on the nozzle size you are using will limit the minimum thickness of the wall. The best way to test the min. Thickness is create a cube, then slice it with 0% in-fill with 1 perimeter, stop it before the top layer gets made and measure the wall thickness. I use a 0.25mm nozzle and my min. wall is 0.34mm.

hi lotw,

yes I have calibrated esteps to extrude 50mm in feed when pressing extrude 50mm. Done exactly. However I had to adjust nozzle size lower to get the correct wall thickness. Is this the wrong way to do it then? My 0.5mm j head produces about 0.6 extruded fillament in air and the single wall thickness was coming out too thick.. I also had to adjust the extrusion multiplier

Here are the results of wall thickness with different nozzle size and extrusion multipler
default- nozzle 0.5, extrusion multiplier 1 - 1 wall thickness: 0.79
example 2- nozzle 0.4, extrusion multiplier 1- wall thickness: 0.65
current settings to provide correct wall thickness: nozzle size 0.4, extrusion multiplier 0.88- 1 wall thickness: 0.52

So maybe somehow I have incorrectly calibrated the esteps per mm?
But how? I did this very carefully to get the exact figure fillament infeed. I did this many times.
How else can it be wrong?

are you slowing down your print when item is printing? you should make minimum speed around 15-20mm a second to ensure that oozing effect is minimized. the print is short enough probably does not need cooling feature, just a fan blowing over object.

hi mate,

no thats not it, I am aware of that problem, must be something else that is causing it.

So when others print an stl with a given wall thickness rather than a solid stl and no infill they get perfect results?

Still no closer to working this one out. I can print perfectly untill it comes to adding wall thickness in the stl?
What can be the problem here?

can you post your configuration file you use in your slicer program?

Sure, thanks for helping. The first part is the print file, the second part is fillament file and last part is printer file.


# generated by Slic3r 0.9.9-dev on Tue Apr 16 11:38:55 2013
avoid_crossing_perimeters = 0
bottom_solid_layers = 0
bridge_acceleration = 0
bridge_flow_ratio = 1
bridge_speed = 60
brim_width = 0
complete_objects = 0
default_acceleration = 0
external_perimeter_speed = 100%
external_perimeters_first = 0
extra_perimeters = 1
extruder_clearance_height = 20
extruder_clearance_radius = 20
extrusion_width = 0
fill_angle = 45
fill_density = 1
fill_pattern = rectilinear
first_layer_extrusion_width = 0
first_layer_height = 100%
first_layer_speed = 30%
gap_fill_speed = 20
gcode_comments = 0
infill_acceleration = 0
infill_every_layers = 1
infill_extruder = 1
infill_extrusion_width = 0
infill_first = 0
infill_only_where_needed = 0
infill_speed = 80
layer_height = 0.2
min_skirt_length = 0
notes =
only_retract_when_crossing_perimeters = 0
output_filename_format = [input_filename_base].gcode
perimeter_acceleration = 0
perimeter_extruder = 1
perimeter_extrusion_width = 0
perimeter_speed = 50
perimeters = 1
post_process =
raft_layers = 0
randomize_start = 1
resolution = 0
skirt_distance = 6
skirt_height = 1
skirts = 1
small_perimeter_speed = 50
solid_fill_pattern = rectilinear
solid_infill_below_area = 5
solid_infill_every_layers = 0
solid_infill_extrusion_width = 0
solid_infill_speed = 80
support_material =
support_material_angle = 0
support_material_enforce_layers = 0
support_material_extruder = 1
support_material_extrusion_width = 0
support_material_interface_layers = 0
support_material_interface_spacing = 0
support_material_pattern = rectilinear
support_material_spacing = 2
support_material_speed = 60
support_material_threshold = 0
threads = 2
top_infill_extrusion_width = 0
top_solid_infill_speed = 50
top_solid_layers = 0
travel_speed = 90

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# generated by Slic3r 0.9.9-dev on Sat Apr 13 19:19:38 2013
bed_temperature = 0
bridge_fan_speed = 100
cooling = 1
disable_fan_first_layers = 1
extrusion_multiplier = 1
fan_always_on = 0
fan_below_layer_time = 60
filament_diameter = 2.8
first_layer_bed_temperature = 0
first_layer_temperature = 200
max_fan_speed = 100
min_fan_speed = 35
min_print_speed = 10
slowdown_below_layer_time = 15
temperature = 175

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# generated by Slic3r 0.9.9-dev on Sat Apr 13 19:33:25 2013
bed_size = 290,275
end_gcode = M104 S0 ; turn off temperature\nG28 X0 ; home X axis\nM84 ; disable motors
extruder_offset = 0x0
gcode_flavor = reprap
layer_gcode =
nozzle_diameter = 0.5
print_center = 145,137.5
retract_before_travel = 2
retract_layer_change = 1
retract_length = 1
retract_length_toolchange = 10
retract_lift = 0.1
retract_restart_extra = 0
retract_restart_extra_toolchange = 0
retract_speed = 50
start_gcode = G28 ; home all axes\nG1 Z5 F5000 ; lift nozzle
toolchange_gcode =
use_relative_e_distances = 0
vibration_limit = 0
z_offset = 0

No longer using Slic3r, but your extrusion widths should not be 0, that's the only obvious thing I see in your settings. I get the best prints, reguardless of what slicer, with extrusion widths equal to nozzle diameter.

Having any Z lift on retraction usually causes more problems than it's worth.

Edited 1 time(s). Last edit at 04/16/2013 10:24AM by Dirty Steve.

I set my extrusion widths to whatever a thin wall object prints, for instance I used a 20mm square with 1 loop and no fill. Measured and use that number

I personally don't use the thin wall extrusion method, because the width will vary with feedrate, and variances in filament diameter.

Thanks a lot for your help, that seems to have fixed the problem. At some point I changed the default extrusion thickness to 0 because it says in slicer to set for 0 for default. a bit of a trick.