Strange rings pattern on my delta

Hi, this is the first time I print such a large base on my printer, and with the right light angle, saw these repeating rings pattern.

Anyone have ideas what's causing this. The fact is these flat rings transpose on vertical walls as well.

Thank you!




Printed on Boots Industries BI V2.5 with Marlin firmware using Pico hotend driven by EZStruder (bowden), GT2 belt (inverted at top), 16 tooth pulley.

Could it be that the rings are at the same place, where your auto Z-Probe is making the mesuring?

My guess is that it's caused by too course a steps/mm value for the carriages, e.g. because you are using less than the usual 1/16 microstepping. 80 steps/mm is common, giving a vertical resolution of about 0.012mm. I guess it's also possible that it's caused by Delta segmentation - does the pattern change if you alter the segments per second or the print speed?

Edited 1 time(s). Last edit at 05/22/2015 03:59AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I see the same kind of thing on my kossel mini... No Idea as to what causes it yet.

I have printed two 50x50x50 mm boxes in Slic3r 1.2.6 vase mode (1 perimeter for walls and for bottom, no top, no infill) using Kossel Mini + 1/16 steppers (A4988) + latest Repetier 0.92 firmware (from git, using EXACT_DELTA_MOVES setting). Using PLA 1.75mm with E3D v6 0.4mm (210C hotend, 65C bed). 0.1mm layer height.

On first photo speed changed from 50% to 450% of base speed 40 mm/second - from 20mm/s to 180mm/s every 5 millimeters from left to right on photo (50, 75, 100, 150, 200, 250, 300, 350, 400, 450 in percents). Using 180 segments per second for print in Repetier firmware:


On second photo speed is constant (40 mm/s), but segmentation changed every 5 millimeters from 350 segments per second to 10 segments per second (350, 300, 250, 200, 150, 100, 75, 50, 25, 10) from left to right on photo.


So, this moire depends on segmentation and speed.

David, can you print such model in your segmentation-free firmware?
OpenSCAD code for model is "cube([50, 50, 50]);"

Edited 2 time(s). Last edit at 05/25/2015 12:16PM by roboprint.

Quote
roboprint
So, this moire depends on segmentation and speed.

David, can you print such model in your segmentation-free firmware?
OpenSCAD code for model is "cube([50, 50, 50]);"

As it happens, I've just rebuilt my delta to increase the height to 1m and use 2020 extrusions instead of 1515, and I am about to do my first print. So I'll use that cube. Just give me a minute to autocalibate...

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
As it happens, I've just rebuilt my delta to increase the height to 1m and use 2020 extrusions instead of 1515, and I am about to do my first print. So I'll use that cube. Just give me a minute to autocalibate...

Looks like your autocalibration is not as fast as you say

Quote
roboprint

Quote
dc42
As it happens, I've just rebuilt my delta to increase the height to 1m and use 2020 extrusions instead of 1515, and I am about to do my first print. So I'll use that cube. Just give me a minute to autocalibate...

Looks like your autocalibration is not as fast as you say

I hadn't allowed for my daughter phoning me for the first time in several months, and being on the phone for well over an hour I also had to set up new probe coordinates. Anyway, it's printing now.



Unfortunately I forgot to reduce the infill from my usual 60% when slicing it, so it's estimating another 1h20 print time.

Edited 1 time(s). Last edit at 05/25/2015 06:40PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Oh, it is so big

Infill can affect perimeter quality, so I recommend to use Slic3r's vase mode (hotend constantly moving up while printing perimeter, there is no layers with constant height).

Here's the result, printed in PLA at 200C at 0.25mm layer height using a 0.4mm nozzle:



The size came out as 49.96 x 49.98 x 49.79mm high, so the calibration seems OK. Looks like it's under-extruding slightly, probably because I reduced the extrusion factor to 95% because it appeared to be over extruding a few layers from the bottom. The print speed for the top infill was 100mm/sec.

I'll try it in spiral vase mode now.

Edited 3 time(s). Last edit at 05/26/2015 03:46AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

This is box top side. Can you show box walls?

Quote
roboprint
This is box top side. Can you show box walls?

I just edited the post to show one of the sides, after I realised that is what your photo shows. I think the blobs are there because I have slic3r set to "randomize seams".

Edited 1 time(s). Last edit at 05/26/2015 03:47AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Here is the spiral vase version, two adjacent sides:



I was a little clumsy in trying to remove it from the bed (which is now too big to fit in the freezer - I didn't think of that as a requirement when I designed the rebuild!), hence the split.

EDIT: I changed the photos, now they are in the same orientation as yours. The slight circular fringes I can see must be an artefact of the camera, because they are not there when I look at the print directly.

Edited 5 time(s). Last edit at 05/26/2015 05:59AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Cannot see any moire, rings or other on photos, but overall print quality is little worse, as I can understand. Layes shifted one relative to other.


Looks like I must switch from mega2560+repetier-firmware to something like smoothieboard 2.0 + smoothieware with segmentation-free movements

Edited 1 time(s). Last edit at 05/26/2015 06:21AM by roboprint.

There does seem to be a slight shift between layers sometimes, but it's early days for this printer - I haven't tweaked the movement settings or motor currents yet. What acceleration and maximum jerk speeds did you use for your print? And which slicer did you use?

Unless it has changed recently, Smoothieware uses segmentation to do delta movement.

Edited 2 time(s). Last edit at 05/26/2015 09:43AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Acceleration is 2500 mm/s^2 for movements and for printing, jerk is 30. Latest Repetier-Firmware from github, exact delta moves setting. Slicer was Slic3r 1.2.6. Spiral vase mode, 1 bottom solid layer, no infill, no top, 0.1mm layer height, settings is here:

; avoid_crossing_perimeters = 1
; bed_shape = 87.0207x9.14624,85.5879x18.1923,83.2174x27.039,79.9352x35.5895,75.7772x43.75,70.789x51.4312,65.0252x58.5489,58.5489x65.0252,51.4312x70.789,43.75x75.7772,35.5895x79.9352,27.039x83.2174,18.1923x85.5879,9.14624x87.0207,0x87.5,-9.14624x87.0207,-18.1923x85.5879,-27.039x83.2174,-35.5895x79.9352,-43.75x75.7772,-51.4312x70.789,-58.5489x65.0252,-65.0252x58.5489,-70.789x51.4312,-75.7772x43.75,-79.9352x35.5895,-83.2174x27.039,-85.5879x18.1923,-87.0207x9.14624,-87.5x0,-87.0207x-9.14624,-85.5879x-18.1923,-83.2174x-27.039,-79.9352x-35.5895,-75.7772x-43.75,-70.789x-51.4312,-65.0252x-58.5489,-58.5489x-65.0252,-51.4312x-70.789,-43.75x-75.7772,-35.5895x-79.9352,-27.039x-83.2174,-18.1923x-85.5879,-9.14624x-87.0207,0x-87.5,9.14624x-87.0207,18.1923x-85.5879,27.039x-83.2174,35.5895x-79.9352,43.75x-75.7772,51.4312x-70.789,58.5489x-65.0252,65.0252x-58.5489,70.789x-51.4312,75.7772x-43.75,79.9352x-35.5895,83.2174x-27.039,85.5879x-18.1923,87.0207x-9.14624,87.5x0
; bed_temperature = 65
; before_layer_gcode = 
; bridge_acceleration = 0
; bridge_fan_speed = 100
; brim_width = 0
; complete_objects = 0
; cooling = 0
; default_acceleration = 0
; disable_fan_first_layers = 3
; duplicate_distance = 6
; end_gcode = M104 S0 ; turn off temperature\nM140 S0 ; bed temperature\nG28 ; home X axis\nM84     ; disable motors\nM106 S255\n
; extruder_clearance_height = 20
; extruder_clearance_radius = 20
; extruder_offset = 0x0
; extrusion_axis = E
; extrusion_multiplier = 1
; fan_always_on = 0
; fan_below_layer_time = 60
; filament_diameter = 1.75
; first_layer_acceleration = 0
; first_layer_bed_temperature = 65
; first_layer_extrusion_width = 150%
; first_layer_speed = 50%
; first_layer_temperature = 215
; gcode_arcs = 0
; gcode_comments = 0
; gcode_flavor = reprap
; infill_acceleration = 0
; infill_first = 0
; layer_gcode = 
; max_fan_speed = 100
; min_fan_speed = 35
; min_print_speed = 10
; min_skirt_length = 0
; notes = 
; nozzle_diameter = 0.4
; only_retract_when_crossing_perimeters = 0
; ooze_prevention = 0
; output_filename_format = [input_filename_base].gcode
; perimeter_acceleration = 0
; post_process = 
; pressure_advance = 0
; resolution = 0
; retract_before_travel = 4
; retract_layer_change = 0
; retract_length = 4
; retract_length_toolchange = 10
; retract_lift = 0.5
; retract_restart_extra = 0
; retract_restart_extra_toolchange = 0
; retract_speed = 70
; skirt_distance = 6
; skirt_height = 1
; skirts = 2
; slowdown_below_layer_time = 5
; spiral_vase = 1
; standby_temperature_delta = -5
; start_gcode = M84 S0\nG28 ; home all axes\n
; temperature = 210
; threads = 4
; toolchange_gcode = 
; travel_speed = 80
; 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 = 0.3
; infill_only_where_needed = 0
; interface_shells = 0
; layer_height = 0.1
; 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 = 50
; support_material_threshold = 0
; xy_size_compensation = 0
; bottom_solid_layers = 1
; bridge_flow_ratio = 1
; bridge_speed = 60
; external_fill_pattern = rectilinear
; external_perimeter_extrusion_width = 0
; external_perimeter_speed = 80%
; external_perimeters_first = 0
; extra_perimeters = 1
; fill_angle = 45
; fill_density = 0%
; fill_pattern = rectilinear
; gap_fill_speed = 20
; infill_every_layers = 2
; infill_extruder = 1
; infill_extrusion_width = 0
; infill_overlap = 15%
; infill_speed = 50
; overhangs = 1
; perimeter_extruder = 1
; perimeter_extrusion_width = 0
; perimeter_speed = 50
; perimeters = 1
; small_perimeter_speed = 90%
; solid_infill_below_area = 70
; solid_infill_every_layers = 0
; solid_infill_extruder = 1
; solid_infill_extrusion_width = 0
; solid_infill_speed = 80%
; thin_walls = 1
; top_infill_extrusion_width = 0
; top_solid_infill_speed = 80%
; top_solid_layers = 0

I'm using Kossel Mini with v-rollers from builda3dprinter.eu, E3D v6 hotend with 0.4mm nozzle, ramps 1.4 + arduino mega 2560 + a4988 drivers + graphic lcd (12864), printing from sd-card

No model cooling.

There is more photos:

Left box is printed with constant speed (40 mm/sec) and changing segments per second from 10 (left on picture, top on box) to 350 (right on picture, bottom of box) as I said before. Left side of box is top, right side is bottom. Right box is printed with constant speed (40mm/sec) and constant segments per second (180) setting:


This moire on photo is depends on segmentation. On left box moire pattern changes every 5 mm, on right box moire pattern is unchanged.


Smoothie uses segmentation, but they have plans to implement segmentation-free movements: [forums.reprap.org]

I sorted out a sticky carriage on my machine, reduced the maximum jerk rate, and adjusted my slic3r settings to match your speed and layer height. This is the result:



Edited 1 time(s). Last edit at 05/26/2015 01:58PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Very good results. Thank you for tests and photos. This is one more reason to start using 32-bit controllers with right firmware. I'm C++ programmer, but not very familiar with programming ARM microcontrollers. I tried to compile ARM repetier-firmware for my Tiva C Lanchpad (80 MHz Cortex M4F with FPU, 256 KB flash, 32 KB RAM), and now I'm able to compile firmware for Tiva C using Energia IDE with ADC/Timers/UART stuff commented out from HAL.c/HAL.h, but work with ADC, Timers and so on is hell for me. It seems what it will easier to buy specialized board like Duet or Smoothieware.

What pulleys, belts, motors are you using? I'm using 16-teeth pulleys (GT2 belts) with 200-steps/rev motors and 1/16 microstepping, so it is 100 steps/mm for each carriage.

Quote
roboprint
What pulleys, belts, motors are you using? I'm using 16-teeth pulleys (GT2 belts) with 200-steps/rev motors and 1/16 microstepping, so it is 100 steps/mm for each carriage.

I'm also using GT2 belts, 1/16 microstepping and 1.8 degree/step motors, however I have 80 microsteps/mm. I guess the pulleys (which came with my original Mini Kossel kit) must have 20 teeth.

PS - Thanks for providing details of the test piece!

Edited 1 time(s). Last edit at 05/26/2015 06:31PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

David, thank you! There is first printed thing with new Duet electronics and your newest RepRapFirmware 1.09d:



Visible moire rings still exists, but there is no more segmentation-dependent moire. It seems that now I need to pay attention to the mechanics.