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Prusa i3 - Perpendicular Collisions

Posted by Tom_Hanks 
Prusa i3 - Perpendicular Collisions
December 13, 2015 11:30PM
Printer is from Folgertech.com and is the 2020 Prusa i3.

I have tried absolutely everything. My print bed is good, I'm not having any issue with adhesion, but as soon as the extruder moves from the first infill to start the second outline of the object it cuts through the previous print. Usually, by the time it gets to the third or fourth layer it's started to turn into a pile of mush. It's almost like the Z axis isn't rising high enough in-between layers? I've attached a few pictures below and my config is:

Marlin Firmware
Repetier-Host 1.6 w/ Slicer

Travel Feed Rate: 4800
Z-Axis Feed Rate: 420
Manual Extrusion Speed: 2
Manual Retraction Speed: 30

Feedrate: 100
Flowrate: 60
Bed Temp: 95
Extruder Temp: 225

Slicer

Layer Height: 0.4
First Layer Height: 50%
Perimeters: 2
Solid Layers: 3/3
Fill Density: 15%

Any help is greatly appreciated!
Attachments:
open | download - 3d-print.JPG (529.7 KB)
Re: Prusa i3 - Perpendicular Collisions
December 13, 2015 11:48PM
Could it be the nozzle on the extruder leaking? I just looked at the top of it and there is quite a significant amount of pla.
Attachments:
open | download - hot-end.JPG (90.5 KB)
Re: Prusa i3 - Perpendicular Collisions
December 14, 2015 12:07AM
Tom,

Need more info:
- Have you just started printing with this printer?
- What is the nozzle orifice diameter?
- Can you attach a link to the gcode file? Or better yet: copy, paste all the settings from the top and very bottom of the gcode.

I can't say about the ooze at the top (don't have that hot end).

The print looks very over extruded.
Have you done an initial extruder calibration? See here.

One clue that you might not have is using a flowrate of 60%. If the extruder is calibrated properly then you should not need to compensate more than a few %, when changing to a different roll of filament etc.

Edit: Also you may want to check your extruder temp setting, 225 is pretty hot for PLA, it will get more runny.

Edited 1 time(s). Last edit at 12/14/2015 12:09AM by Paul Wanamaker.


My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!
Re: Prusa i3 - Perpendicular Collisions
December 14, 2015 01:26AM
Yes, this is my first printer.
Nozzle is .04

I am currently in the process of calibrating the e steps. I have been up and down with the temp to no avail.


external perimeters extrusion width = 0.40mm
; perimeters extrusion width = 0.42mm
; infill extrusion width = 0.42mm
; solid infill extrusion width = 0.42mm
; top infill extrusion width = 0.42mm

M190 S70 ; set bed temperature
M104 S219 ; set temperature
G28 ; home all axes
G1 Z5 F5000 ; lift nozzle

M109 S219 ; wait for temperature to be reached
G21 ; set units to millimeters
G90 ; use absolute coordinates
M82 ; use absolute distances for extrusion
G92 E0
M106 S255
G1 E-1.00000 F1800.00000
G92 E0

external perimeters extrusion width = 0.40mm
; perimeters extrusion width = 0.42mm
; infill extrusion width = 0.42mm
; solid infill extrusion width = 0.42mm
; top infill extrusion width = 0.42mm

M190 S70 ; set bed temperature
M104 S219 ; set temperature
G28 ; home all axes
G1 Z5 F5000 ; lift nozzle

M109 S219 ; wait for temperature to be reached
G21 ; set units to millimeters
G90 ; use absolute coordinates
M82 ; use absolute distances for extrusion
G92 E0
M106 S255
G1 E-1.00000 F1800.00000
G92 E0
Re: Prusa i3 - Perpendicular Collisions
December 14, 2015 01:28AM
G92 E0
M107
M104 S0 ; turn off temperature
G28 X0 ; home X axis
M84 ; disable motors

; filament used = 1288.6mm (3.1cm3)

; avoid_crossing_perimeters = 1
; bed_shape = 0x0,200x0,200x200,0x200
; bed_temperature = 70
; before_layer_gcode =
; bridge_acceleration = 0
; bridge_fan_speed = 100
; brim_width = 0
; complete_objects = 0
; cooling = 1
; default_acceleration = 0
; disable_fan_first_layers = 0
; duplicate_distance = 6
; end_gcode = M104 S0 ; turn off temperature\nG28 X0 ; home X axis\nM84 ; disable motors\n
; extruder_clearance_height = 20
; extruder_clearance_radius = 20
; extruder_offset = 0x0
; extrusion_axis = E
; extrusion_multiplier = 1
; fan_always_on = 1
; fan_below_layer_time = 60
; filament_colour = #FFFFFF
; filament_diameter = 1.75
; first_layer_acceleration = 0
; first_layer_bed_temperature = 70
; first_layer_extrusion_width = 0
; first_layer_speed = 50%
; first_layer_temperature = 219
; gcode_arcs = 0
; gcode_comments = 0
; gcode_flavor = reprap
; infill_acceleration = 0
; infill_first = 0
; layer_gcode =
; max_fan_speed = 100
; max_print_speed = 80
; max_volumetric_speed = 0
; min_fan_speed = 100
; min_print_speed = 10
; min_skirt_length = 0
; notes =
; nozzle_diameter = 0.4
; only_retract_when_crossing_perimeters = 1
; ooze_prevention = 0
; output_filename_format = [input_filename_base].gcode
; perimeter_acceleration = 0
; post_process =
; pressure_advance = 0
; resolution = 0
; retract_before_travel = 2
; retract_layer_change = 1
; retract_length = 1
; retract_length_toolchange = 10
; retract_lift = 0
; retract_restart_extra = 0
; retract_restart_extra_toolchange = 0
; retract_speed = 30
; skirt_distance = 3
; skirt_height = 1
; skirts = 3
; slowdown_below_layer_time = 30
; spiral_vase = 0
; standby_temperature_delta = -5
; start_gcode = G28 ; home all axes\nG1 Z5 F5000 ; lift nozzle\n
; temperature = 219
; threads = 2
; toolchange_gcode =
; travel_speed = 150
; use_firmware_retraction = 0
; use_relative_e_distances = 0
; use_volumetric_e = 0
; vibration_limit = 0
; wipe = 0
; z_offset = 0
; dont_support_bridges = 1
; extrusion_width = 0
; first_layer_height = 50%
; infill_only_where_needed = 0
; interface_shells = 0
; layer_height = 0.4
; raft_layers = 0
; seam_position = aligned
; support_material = 0
; support_material_angle = 0
; support_material_contact_distance = 0.2
; 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_interface_speed = 100%
; support_material_pattern = pillars
; support_material_spacing = 2.5
; support_material_speed = 60
; support_material_threshold = 0
; xy_size_compensation = 0
; bottom_solid_layers = 3
; bridge_flow_ratio = 1
; bridge_speed = 60
; external_fill_pattern = rectilinear
; external_perimeter_extrusion_width = 0
; external_perimeter_speed = 90%
; external_perimeters_first = 0
; extra_perimeters = 1
; fill_angle = 45
; fill_density = 10%
; fill_pattern = honeycomb
; gap_fill_speed = 35
; infill_every_layers = 1
; infill_extruder = 1
; infill_extrusion_width = 0
; infill_overlap = 15%
; infill_speed = 50
; overhangs = 1
; perimeter_extruder = 1
; perimeter_extrusion_width = 0
; perimeter_speed = 40
; perimeters = 4
; small_perimeter_speed = 40
; solid_infill_below_area = 70
; solid_infill_every_layers = 0
; solid_infill_extruder = 1
; solid_infill_extrusion_width = 0
; solid_infill_speed = 45
; thin_walls = 1
; top_infill_extrusion_width = 0
; top_solid_infill_speed = 45
; top_solid_layers = 3
Re: Prusa i3 - Perpendicular Collisions
December 14, 2015 03:21AM
Calibrate your hardware first, then your slicer.
If you still have bad prints after that we can investigate.
There is simply no point in trying to fix this print through different settings if your hardware is not up to it.
Re: Prusa i3 - Perpendicular Collisions
December 14, 2015 03:05PM
Downunder35m is right.

A couple thoughts to make calibrating easier:

- If you have a .40 nozzle, then you should not use a layer height greater than 80% of .4, so .32 would be the max. I recommend you stick with .2mm as a good place to start. If you go over that then extrusion rate increases a lot, and if you go under (say .1mm layer height) then the extrusion calibration has to be very exact).

- When calibrating, keep all your print speeds the same, and not too fast, say 50mms or slower. This is for three reasons, 1) there are large pressure fluctuations with different extrusion speeds, 2) if you leave them at 0 then Slic3r will set them for you, and you will not know what they will be without looking in the gcode, and 3) you don't know what your extruder's max mm3/second output is yet - too fast and you will have many issues.

- When doing initial calibrating, set your extrusion widths the same. If you leave them at auto (0) then Slic3r will do what it thinks is the max your extruder can handle for some areas, and it will cause a great variation in pressure in the extruder, and you will not know what the perimeter widths will be without looking in the gcode (it's documented at the top) - making it harder to calibrate.

- For reliability the extrusion width should be > nozzle diameter and < 1.7x nozzle diameter (searching for a source on the last, this kind of information is scattered all over). For a .4 nozzle that would be between .42 and .68mm, with .5mm being a good reliable value. There is a magic formula for setting the extrusion width/layer height for good layer adhesion, but this will be close.

Here is a good guide for fine tuning your flow rate.
Also the Calibration section.

After you have the initial calibration done, then change other parameters like speed and extrusion width one at a time until you know how Slic3rs settings affect things. However, keeping the pressure consistent while calibrating greatly simplifies things.

Hope that helps!
Re: Prusa i3 - Perpendicular Collisions
December 16, 2015 07:09PM
I can't even calibrate this thing in a basic sense.

I've been trying to calibrate the "E-Steps" by adjusting the STEPS_PER_UNIT. This is what I had by default, I've tried several different methods, but nothing seems to work.

]#define DEFAULT_AXIS_STEPS_PER_UNIT {80, 80, 4000, 6675} // default steps per unit for Ultimaker

If I ask for 100mm of filament it will give me anywhere from 220 to 270mm, depending on what the fourth value is. I calculated that it should actually be around 361.44, which worked great. I was getting like 17mm, if I asked for 10mm, but the extruder was making a terrible grinding sound. I pulled the hotend off and loosened the tension screw....well that threw everything out the window, I am now getting 300mm for every 100mm... so I played with the tension and tightened it back up, but nothing resulted. I can't even get it back to the grinding noise. I tried adjusting the E-steps value, went a little lower, back up, and everywhere in between, but it will only change by 20 to 30mm.

Could it be a motor or driver issue? I've tried adjusting the extruder tension as well and it just crams the filament threw. varying the total length by 10 to 20mm.

This is my first 3D printer so if I'm missing something obvious here please let me know.This wasn't a very expensive kit, should I just replace the extruder/hotend and save myself a headache?

Thanks in advance!
Re: Prusa i3 - Perpendicular Collisions
December 16, 2015 07:40PM
How much comes out is not related to your tension, just the Esteps.
Change the values in the EEPROM till you got it right, then flash the values as a new firmware.
Re: Prusa i3 - Perpendicular Collisions
December 17, 2015 12:39AM
Luckily, they sent 5 motor drivers, I switched the extruder's out for the other one and it's working great now! I was able to get it semi-calibrated rather quickly, but....

Now I'm having an issue with the Gcode, I keep getting a few different errors, but I'm not really sure what's causing them. It will stop randomly in the middle of the print.

23:35:51.018 : Error:Line Number is not Last Line Number+1, Last Line: 5483
23:35:51.018 : Resend: 5484
23:35:51.111 : Error:checksum mismatch, Last Line: 5502
23:35:51.111 : Resend: 5503
23:35:53.576 : Error:checksum mismatch, Last Line: 5507
23:35:53.592 : Resend: 5508
23:35:55.916 : Error:checksum mismatch, Last Line: 5510
23:35:55.916 : Resend: 5511
23:35:59.676 : Error:checksum mismatch, Last Line: 5514
23:35:59.676 : Resend: 5515
23:36:09.350 : Error:Line Number is not Last Line Number+1, Last Line: 5536
23:36:09.350 : Resend: 5537
23:36:09.724 : Error:checksum mismatch, Last Line: 5542
23:36:09.724 : Resend: 5543
23:36:10.208 : Error:Line Number is not Last Line Number+1, Last Line: 5546
23:36:10.208 : Resend: 5547
23:36:11.705 : Error:Line Number is not Last Line Number+1, Last Line: 5569
23:36:11.705 : Resend: 5570
23:36:12.752 : Error:checksum mismatch, Last Line: 5584
23:36:12.752 : Resend: 5585
23:36:12.942 : Error:Line Number is not Last Line Number+1, Last Line: 5587
23:36:12.942 : Resend: 5588
23:36:13.597 : Error:checksum mismatch, Last Line: 5595
23:36:13.597 : Resend: 5596
23:36:13.989 : Error:checksum mismatch, Last Line: 5600
23:36:13.989 : Resend: 5601
23:36:15.771 : Error:checksum mismatch, Last Line: 5622
23:36:15.771 : Resend: 5623
23:36:16.021 : Error:checksum mismatch, Last Line: 5626
23:36:16.021 : Resend: 5627
23:36:17.924 : Error:No Line Number with checksum, Last Line: 5649
23:36:17.924 : Error:Line Number is not Last Line Number+1, Last Line: 5649
23:36:17.924 : Resend: 5650
23:36:18.127 : Error:No Line Number with checksum, Last Line: 5653
23:36:18.158 : Error:Line Number is not Last Line Number+1, Last Line: 5653
23:36:18.174 : Resend: 5654
23:36:18.626 : Error:checksum mismatch, Last Line: 5659
23:36:18.626 : Resend: 5660
23:36:18.657 : Error:No Line Number with checksum, Last Line: 5659
23:36:18.829 : Error:checksum mismatch, Last Line: 5661
23:36:18.829 : Resend: 5662
23:36:19.188 : Error:checksum mismatch, Last Line: 5665
23:36:19.203 : Resend: 5666
23:36:19.547 : Error:checksum mismatch, Last Line: 5670
23:36:19.547 : Resend: 5671
23:36:22.167 : Error:Line Number is not Last Line Number+1, Last Line: 5675
23:36:22.167 : Resend: 5676
23:36:24.492 : Error:Line Number is not Last Line Number+1, Last Line: 5679
23:36:24.492 : Resend: 5680
23:36:29.531 : Error:checksum mismatch, Last Line: 5686
23:36:29.531 : Resend: 5687
23:36:35.414 : Error:Line Number is not Last Line Number+1, Last Line: 5692
23:36:35.429 : Resend: 5693


This is just a small chunk, any idea?
Re: Prusa i3 - Perpendicular Collisions
December 17, 2015 10:53PM
These are communications errors.
If you can print from SD card it will be much more reliable.
Or get a better usb cable. Make sure it is not running next to motor wires.
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