Anyone Have Good Slic3r Configs for Bridging?

Any of you print masters out there have a good Slic3r configuration for printing bridges in ABS?
I’ve been experimenting for days, but cannot find a combination that will not severely droop or totally lose a starting edge on a bridge. I’m only trying to go about 25mm, but have had nothing but failures with everything I try. I have changed flow between .8 to 1.1. I have tried fan speeds up to 100%, but that cools the nozzle as well as the filament at anything above 60%. Still doesn’t help. I’ve tried print speeds from 15mm/sec up to 120mm/sec. I can’t find a combination that works! HEEEEELLLLLPPPPP!!! please…

What size nozzle do you want it for?

Edit also what nozzle temperature are you running?

Well, here’s my general Slic3r go to printer configuration. it’s currently set for 2.98mm diameter filliament. This is for SLic3r 1.0 Rc3 on a 0.5mm nozzle, 0.5mm brim enabled, no support, 85% infill. This is customized to make almost no “elephant foot” on the bed, so if you have trouble with adhesion, this profile is not a good idea for you. I print generally at 240c and 100c on the bed. My printer is also NOT stock, so my results may not match what you get. At any rate, there it is if you want it, use at your own risk, no refunds, etc.


# generated by Slic3r 1.0.0RC3 on Thu Jan 14 22:05:05 2016
avoid_crossing_perimeters = 
bed_size = 298,275
bed_temperature = 0
bottom_solid_layers = 2
bridge_acceleration = 1500
bridge_fan_speed = 40
bridge_flow_ratio = 1.01
bridge_speed = 35
brim_width = 5
complete_objects = 0
cooling = 1
default_acceleration = 1100
disable_fan_first_layers = 1
duplicate = 1
duplicate_distance = 6
duplicate_grid = 1,1
end_gcode = M104 S0 ; turn off extruder temperature\nM140 S0 ; turn off bed\nM107 ; turn off Extruder Fans\nG28 X0 Y0  ; home X axis Y axis\nG1 Y250 ; kick out bed\nM84     ; disable motors
external_perimeter_speed = 90
external_perimeters_first = 
extra_perimeters = 1
extruder_clearance_height = 20
extruder_clearance_radius = 20
extruder_offset = 0x0
extrusion_axis = E
extrusion_multiplier = 1
extrusion_width = 0
fan_always_on = 0
fan_below_layer_time = 60
filament_diameter = 2.98
fill_angle = 45
fill_density = 0.85
fill_pattern = rectilinear
first_layer_acceleration = 1000
first_layer_bed_temperature = 0
first_layer_extrusion_width = 180%
first_layer_height = 0.4
first_layer_speed = 65%
first_layer_temperature = 0
g0 = 0
gap_fill_speed = 45
gcode_arcs = 0
gcode_comments = 0
gcode_flavor = reprap
infill_acceleration = 3000
infill_every_layers = 1
infill_extruder = 1
infill_extrusion_width = 0
infill_first = 0
infill_only_where_needed = 0
infill_speed = 130
layer_gcode = 
layer_height = 0.3
max_fan_speed = 25
min_fan_speed = 0
min_print_speed = 45
min_skirt_length = 0
notes = 
nozzle_diameter = 0.5
only_retract_when_crossing_perimeters = 1
ooze_prevention = 0
output_filename_format = [input_filename_base].gcode
overhangs = 
perimeter_acceleration = 1050
perimeter_extruder = 1
perimeter_extrusion_width = 0
perimeter_speed = 115
perimeters = 4
post_process = 
print_center = 149,138
raft_layers = 0
randomize_start = 0
resolution = .01
retract_before_travel = 2
retract_layer_change = 1
retract_length = 2
retract_length_toolchange = 10
retract_lift = 0
retract_restart_extra = 0
retract_restart_extra_toolchange = 0
retract_speed = 25
rotate = 0
scale = 1
skirt_distance = 6
skirt_height = 1
skirts = 2
slowdown_below_layer_time = 25
small_perimeter_speed = 75
solid_fill_pattern = rectilinear
solid_infill_below_area = 40
solid_infill_every_layers = 0
solid_infill_extrusion_width = 0
solid_infill_speed = 115
spiral_vase = 0
standby_temperature_delta = -5
start_gcode = G28 ; home all axes\nM203 X192 Y208 Z3 ; Speed limits to minimize skipped steps when moving really fast courtesy of forum.lulzbot.com user 1013
start_perimeters_at_concave_points = 1
start_perimeters_at_non_overhang = 1
support_material = 
support_material_angle = 0
support_material_enforce_layers = 0
support_material_extruder = 1
support_material_extrusion_width = 0
support_material_interface_extruder = 1
support_material_interface_layers = 3
support_material_interface_spacing = 0
support_material_pattern = rectilinear
support_material_spacing = 5.00
support_material_speed = 60
support_material_threshold = 0
temperature = 0
thin_walls = 1
threads = 2
toolchange_gcode = 
top_infill_extrusion_width = 0
top_solid_infill_speed = 80
top_solid_layers = 5
travel_speed = 200
use_firmware_retraction = 0
use_relative_e_distances = 0
vibration_limit = 0
wipe = 0
z_offset = 0

Slic3r_Taz5_05mm_5mmbrim_med.ini (3.32 KB)

Using a .35mm nozzle, 2.94mm Black ABS @ 228°C

Bump the heat up to 240, you should get better interlayer adhesion and stronger bridge lines. For the nozzle size, you’ll need to adjust the nozzle size itself, starting layer thickness (0.25 should work) and subsequent layer height (0.20 probably?) in there. Everything else should work fine.

Apparently, my nozzle runs a bit hot for the temperature it is supposedly reading. If I go much over 230°C my prints start looking like they were squirted by a drunk pastry chef. After much experimentation I have found that 228°C works terrific with my Buddashnozzle v2 and Black ABS. Suppose I could try a little hotter and see what happens.

Oh, yeah if it’s a buddaschnozzle you don’t want to take it up much past 235 anyways, as it will melt the liner.

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Thanks for the help.

What effect do the acceleration parameters have? In looking at my own profiles all of those values are set at zero.

How do you calculate those values?

If they are set to zero, the machine uses either the slic3r or firmware defaults. The values in that particular profile started out as a lulzbot taz 3 ABS profile, and then have been tweaked and modified over time based off ideas in forums, my own testing, and occaisonally math. My printer movement values are probably a bit faster than some. There is a good overview of what they all mean, what they do, and how they can be calculated for adjustment in the slic3r user manual, for example : http://manual.slic3r.org/expert-mode/speed