The bed heater works but immediately resets the duet, as the power supply cannot keep up with the 500 Watts request (it is a 350 Watts PSU). I ordered a 200 Watts bed heater now. I assume the circuit itself is ok, as if it was burn't I wouldn't be seeing any increase in the temperature.

As a side note, I removed the fan connectors, removed the crimps, connected them directly to the PSU to individually test them and they work, so it is probably some bad wiring by me creating the 24 volts fans not working problem.

I read the fan page on the wiki. As I understand, it is possible to either use all 5 volts fans (I don't have any), use all 24 volts fans (in that case I need 1 more 24 volts blower and a 24 volts large fan to cool the Duet board), use all 12 volts fans (in that case I'll need a buck converter, that I already have, and connect the +and - inputs of the converter to my 24 Volts PSU, and connect the positive output to V-fan jumper. I that case, all of the fans (PWM and always on) will be 12 volts. Or in my case, if I want to use 2 24 volts and 2 12 volts fans, I need to apply 24 volts to V-fan jumper (which means I can leave the jumper in place, as my PSU is 24 volts and V in will provide that 24 volts), however for the 12 volt fans I need to apply 12 volts from a buck converter, but the negative ends will go to the Fan - connectors. I assume I can use a single buck converter for supplying 2 12 Volts fans (the buck coverter can output 3 A, so it should be enough). My best option, until I have a all 24 Volts setup, seems to use the last option, which will require a minimal chang in wiring only.

Anything wrong with my understanding?

Hi,

I've recently changed my system from 12 volts to 24 volts. As a result, I've changed my hotend heater. I had a 50 Watts 24 Volts heater, so I used it. Following PID tuning (I am on firmware 3.2), the initial temperature overshoot is 6 degrees when the temperature is set for 200 degrees. Afterwards, it stabilizes and changes between 199.9-200.1 degrees. Then I turn on part cooling fans and it overshoots by 1.4 degrees, then stabilizing at 199.7-199.9 degrees for 30-40 seconds and then stabilizes at 199.9-200.1 When I turn off the cooling fan, the temperature decreases to 198.4, then overshoots to 200.4 and is stabilized at 199.9-200.1

Is the initial overshoot normal/expected? Is the behaviour of the heater in acceptable ranges?

Thanks...

@dc42 @o_lampe @deckingman I've rebuilt the Y carriage, removed the twist that I used for smooth side of the belt on smooth idler, replaced the idler with a toothed one, retensioned. Here's a comparison of the object post-modifications:

It turns out you were right, there should be something related to backlash on my setup. While I still have the artefacts, thery are not as prominent as they were previously. I may still have some ğrpblem on the X axis, which I'll also replace with another solution.

@argo That's very good. It means I have to go back to my printer and look for more mechanical issues....

@deckingman It used to flex a little bit when I was using groove mount on plastic version of my X car. So, I've bought an adapter (this one https://www.aliexpress.com/item/32890582038.html?spm=a2g0o.productlist.0.0.727965c11yqaj9&algo_pvid=a5da6614-4232-4c0e-ba6f-5602b69cf33f&algo_expid=a5da6614-4232-4c0e-ba6f-5602b69cf33f-14&btsid=0b0a555516211823561961742eb46d&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_) , so it is metal on metal now. There was a very slight movement due to tolerances (or bad manufacturing), so I designed a plastic part that plugs to it and ifxes it in place.

There is no movement if you try to move the hotend (of course it is still bolted to plastic and the plastic can flex but I don't imagine it would flex during routine printer movements).

@deckingman Maybe. A problem with this object (with 0.8 mm thick wall) is that the slicer doesn't really consider it as an object with an internal and external perimeter. The fact that it is making a horseshoe turn makes the line a closed single loop, so a single line in fact, even though there should be two lines. I've loaded the 0.8 mm and 1 mm objects, and also another object with thicker walls to Prusa Slicer. Here's how they look at thelevel of a hole:

The object on the bottom has external perimeters (orange) and internal perimeters (yellow). The object on top and right is the 0.8 mm object and it only has orange perimeters, so only external. The obejct on top left is the 1 mm object and while it has some gap fill between the perimeters, they still are external perimeters according to the color. Maybe that's the problem?

So in this object's case, the object starts printing form the external line (even though internal perimeters first is selected) from a very close location to the hole, goes a few cm towards the hole, makes its 180 degree turn and goes to the internal line, finishes that line at the other end of the hole and makes its second turn to finish the external line (I have chosen aligned seems so it starts from very similar locations). Even if I chose to print with the external perimeters first option, it still performs the same trajectory (probably as a result of not having an internal perimeter) .

@dc42 I know that this is the first thing that comes to the mind when seeing this problem, however I am not sure about it. My reasons:

• The object is being printed with the inner perimeters first, so it starts regularly, but then makes the horseshoe turn. This would imply the artefatct to be more visible on the exterior surfaces as the extrusion starts regularly .
• I am using idlers which can be tensioned using bolts and I am using a voice frequency analyzer to tension the belts. They run very straight, with no wobble (I had wobble in the past, which I have corrected now).
• The artefact is extremely regular
• The wall thickness changes depending on the features on the object, so when there is a hole, the wall is thicker and I did cut with a cutter to see if there is a gap between the inner and outer walls, but there isn't any.
• The artefact exists on both X and Y axis

Could it be a side effect of interpolation ? (I don't know how it works, so that might be completely unrelated).

Have you ever printed that object?

@o_lampe The pictures you've posted are from the outside of the object, where the effect is less visible. How does it look from the inside? In my case, the artifact is much more pronounced if you look at the inside walls. The lighting is also very important to be able to see the artifact (for example, in my third picture, it looks like there is no artifact at all at the inside wall, but if you shine the light with the appropiate angle (I used a flashlight) it is visible.

I have tried with and without Arc Welder, there is no visible difference.

Also, a funny coincidence, here's a post I've made 4 years ago, for the same problem in the RepRap forums, guess who did one of the answers belong to
https://reprap.org/forum/read.php?262,760790,760965#msg-760965

@o_lampe That should be interesting. The line width could also be a problem, as the slicer generally uses a slightly larger line width compared to the nozzle (0.45-0.46 instead of 0.4) but I don't think that's the problem, as the same line width will be used for the entire object and any error in wall thickness will be applied to everywhere, so there should be no visible changes.

I changed the nozzle size in Prusa slicer to see how it draws the GCode. As the wall thickness is 0.8 mm, it just creates a single line and goes through the hole instead of looping, so in theory, the artifact shouldn't be visible (It has a similar behaviour for 1 mm thick version too).

@alankilian Thank you very much for sparing some time for printing the object. I am somehow relieved to see that it isn't specific to my printer only.

@3DPMicro The GCode looks perfectly fine when loaded on a GCode viewer. The walls are straight. The STL itself has no visible problems when loaded in Solidworks. It looks as it is intended to look.

@phaedrux The horseshoe shape can be a problem but that is the preferred method for all of the slicers I've tried. None of the slicers try to make that hole by retracting and going straight accross the hole. Maybe that is a fundamental error with the slicers themselves, who calculate the amount of plastic needed. The pressure advance might change how this looks but don't you think it is a huge amount of overextrusion for it to deal with? The pressure advance, especially on a direct drive extruder, isn't supposed to make that much of a change. While this part has been printed without pressure advance, I've used pressure advance in the past and I can still see the same artifacts.

Some more information about my configuration: It is a custom cartesian printer with Duet Wifi 1.04, running firmware 3.2. Bondtech BMG extruder.

.
Here's my config.g:

; Configuration file for Duet WiFi (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.2.3 on Fri May 14 2021 14:28:05 GMT+0300 (GMT+03:00)

; General preferences
G90                                            ; send absolute coordinates...
M83                                            ; ...but relative extruder moves
M550 P"Sigma 3D"                               ; set printer name

; Network
M552 S1                                        ; enable network
M586 P0 S1                                     ; enable HTTP
M586 P1 S0                                     ; disable FTP
M586 P2 S0                                     ; disable Telnet

; Drives
M569 P0 S0                                     ; physical drive 0 goes backwards
M569 P1 S0                                     ; physical drive 1 goes backwards
M569 P2 S1                                     ; physical drive 2 goes forwards
M569 P3 S0                                     ; physical drive 3 goes backwards
M584 X0 Y1 Z2 E3                               ; set drive mapping
M350 X16 Y16 Z16 E16 I1                        ; configure microstepping with interpolation
M92 X80.00 Y80.00 Z400.00 E830.00              ; set steps per mm
M566 X900.00 Y900.00 Z60.00 E1200.00           ; set maximum instantaneous speed changes (mm/min)
M203 X7200.00 Y7200.00 Z180.00 E2400.00        ; set maximum speeds (mm/min)
M201 X700.00 Y700.00 Z30.00 E700.00            ; set accelerations (mm/s^2)
M906 X1400 Y1500 Z1400 E900 I30               ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                        ; Set idle timeout

; Axis Limits
M208 X-20 Y0 Z0 S1                             ; set axis minima
M208 X235 Y220 Z230 S0                         ; set axis maxima

; Endstops
M574 X1 S1 P"!xstop"                           ; configure active-high endstop for low end on X via pin !xstop
M574 Y1 S1 P"!ystop"                           ; configure active-high endstop for low end on Y via pin !ystop
M574 Z0 P"nil" 					; Z has no endstop 
; Z-Probe
M950 S0 C"exp.heater3"                         ; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" H5 F120 T4800            ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X29 Y0 Z0.75                          ; set Z probe trigger value, offset and trigger height
M557 X30:190 Y5:195 S20                        ; define mesh grid

; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B4138 ; configure sensor 0 as thermistor on pin bedtemp
M950 H0 C"bedheat" T0                          ; create bed heater output on bedheat and map it to sensor 0
M307 H0 B0 S1.00                               ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0                                        ; map heated bed to heater 0
M143 H0 S120                                   ; set temperature limit for heater 0 to 120C
M308 S1 P"e0temp" Y"thermistor" T100000 B4725 C7.06e-8  ; configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" T1                           ; create nozzle heater output on e0heat and map it to sensor 1
M307 H1 R2.322 C219.7 D9.80 S1.00 V24.0        ; disable bang-bang mode for heater  and set PWM limit
M143 H1 S300                                   ; set temperature limit for heater 1 to 300C

; Fans
M950 F0 C"fan0" Q500                           ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H-1                                 ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"fan1" Q500                           ; create fan 1 on pin fan1 and set its frequency
M106 P1 S1 H1 T45                              ; set fan 1 value. Thermostatic control is turned on
M950 F2 C"fan2" Q500                           ; create fan 2 on pin fan2 and set its frequency
M106 P2 S1 H-1                                 ; set fan 2 value. Thermostatic control is turned off

; Tools
M563 P0 D0 H1 F0:2                             ; define tool 0
G10 P0 X0 Y0 Z0                                ; set tool 0 axis offsets
G10 P0 R0 S0                                   ; set initial tool 0 active and standby temperatures to 0C

; Custom settings are not defined

; Miscellaneous
M575 P1 S1 B57600                              ; enable support for PanelDue
T0                                             ; select first tool

Here are some settings for the print that I've copied from the GCode:

; generated by PrusaSlicer 2.3.1+win64 on 2021-05-15 at 16:38:11 UTC

; 

; external perimeters extrusion width = 0.45mm
; perimeters extrusion width = 0.45mm
; infill extrusion width = 0.45mm
; solid infill extrusion width = 0.45mm
; top infill extrusion width = 0.40mm

M107
G10 S210 ; set temperature
;TYPE:Custom
M561;Clear bed transforms
G28 XY; Home X and Y axis
M280 P3 S10 I1; BLTouch Pin down
G1 X100 Y100; Go to 100
G28 Z;
G29 S1 ; Bed leveling with already recorded height map
M280 P3 S90 I1; BLTouch pin up
G10 S210 ; set temperature
M116 ; wait for temperature to be reached
G21 ; set units to millimeters
G90 ; use absolute coordinates
M83 ; use relative distances for extrusion
; Filament gcode
; filament used [mm] = 2126.85
; filament used [cm3] = 5.12
; total filament used [g] = 0.00
; total filament cost = 0.00
; estimated printing time (normal mode) = 57m 56s

; avoid_crossing_perimeters = 0
; avoid_crossing_perimeters_max_detour = 0
; bed_custom_model = 
; bed_custom_texture = 
; bed_shape = 0x0,200x0,200x220,0x220
; bed_temperature = 0
; before_layer_gcode = 
; between_objects_gcode = 
; bottom_fill_pattern = monotonic
; bottom_solid_layers = 2
; bottom_solid_min_thickness = 0
; bridge_acceleration = 0
; bridge_angle = 0
; bridge_fan_speed = 100
; bridge_flow_ratio = 1
; bridge_speed = 60
; brim_width = 0
; clip_multipart_objects = 1
; color_change_gcode = M600
; complete_objects = 0
; cooling = 0
; cooling_tube_length = 5
; cooling_tube_retraction = 91.5
; default_acceleration = 0
; default_filament_profile = 
; default_print_profile = 
; deretract_speed = 0
; disable_fan_first_layers = 3
; dont_support_bridges = 1
; draft_shield = 0
; duplicate_distance = 6
; elefant_foot_compensation = 0.2
; end_filament_gcode = "; Filament-specific end gcode \n;END gcode for filament\n"
; end_gcode = M104 S0 ; turn off temperature\nM140 S0 ; turn off bed\nG28 X0  ; home X axis\nM84     ; disable motors\n
; ensure_vertical_shell_thickness = 0
; external_perimeter_extrusion_width = 0
; external_perimeter_speed = 50%
; external_perimeters_first = 0
; extra_loading_move = -2
; extra_perimeters = 1
; extruder_clearance_height = 20
; extruder_clearance_radius = 20
; extruder_colour = ""
; extruder_offset = 0x0
; extrusion_axis = E
; extrusion_multiplier = 1
; extrusion_width = 0
; fan_always_on = 1
; fan_below_layer_time = 60
; filament_colour = #29B2B2
; filament_cooling_final_speed = 3.4
; filament_cooling_initial_speed = 2.2
; filament_cooling_moves = 4
; filament_cost = 0
; filament_density = 0
; filament_diameter = 1.75
; filament_load_time = 0
; filament_loading_speed = 28
; filament_loading_speed_start = 3
; filament_max_volumetric_speed = 0
; filament_minimal_purge_on_wipe_tower = 15
; filament_notes = ""
; filament_ramming_parameters = "120 100 6.6 6.8 7.2 7.6 7.9 8.2 8.7 9.4 9.9 10.0| 0.05 6.6 0.45 6.8 0.95 7.8 1.45 8.3 1.95 9.7 2.45 10 2.95 7.6 3.45 7.6 3.95 7.6 4.45 7.6 4.95 7.6"
; filament_settings_id = "PLA No Heated Bed"
; filament_soluble = 0
; filament_spool_weight = 0
; filament_toolchange_delay = 0
; filament_type = PLA
; filament_unload_time = 0
; filament_unloading_speed = 90
; filament_unloading_speed_start = 100
; filament_vendor = (Unknown)
; fill_angle = 45
; fill_density = 20%
; fill_pattern = grid
; first_layer_acceleration = 0
; first_layer_bed_temperature = 0
; first_layer_extrusion_width = 0
; first_layer_height = 0.2
; first_layer_speed = 30
; first_layer_temperature = 210
; full_fan_speed_layer = 0
; gap_fill_speed = 20
; gcode_comments = 0
; gcode_flavor = reprapfirmware
; gcode_label_objects = 0
; high_current_on_filament_swap = 0
; host_type = octoprint
; infill_acceleration = 0
; infill_anchor = 600%
; infill_anchor_max = 50
; infill_every_layers = 1
; infill_extruder = 1
; infill_extrusion_width = 0
; infill_first = 0
; infill_only_where_needed = 0
; infill_overlap = 25%
; infill_speed = 60
; interface_shells = 0
; ironing = 0
; ironing_flowrate = 15%
; ironing_spacing = 0.1
; ironing_speed = 15
; ironing_type = top
; layer_gcode = 
; layer_height = 0.2
; machine_limits_usage = emit_to_gcode
; machine_max_acceleration_e = 10000,5000
; machine_max_acceleration_extruding = 1500,1250
; machine_max_acceleration_retracting = 1500,1250
; machine_max_acceleration_x = 9000,1000
; machine_max_acceleration_y = 9000,1000
; machine_max_acceleration_z = 500,200
; machine_max_feedrate_e = 120,120
; machine_max_feedrate_x = 500,200
; machine_max_feedrate_y = 500,200
; machine_max_feedrate_z = 12,12
; machine_max_jerk_e = 2.5,2.5
; machine_max_jerk_x = 10,10
; machine_max_jerk_y = 10,10
; machine_max_jerk_z = 0.2,0.4
; machine_min_extruding_rate = 0,0
; machine_min_travel_rate = 0,0
; max_fan_speed = 100
; max_layer_height = 0
; max_print_height = 200
; max_print_speed = 80
; max_volumetric_speed = 0
; min_fan_speed = 100
; min_layer_height = 0.08
; 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
; overhangs = 1
; parking_pos_retraction = 92
; pause_print_gcode = M601
; perimeter_acceleration = 0
; perimeter_extruder = 1
; perimeter_extrusion_width = 0
; perimeter_speed = 50
; perimeters = 3
; physical_printer_settings_id = 
; post_process = 
; print_settings_id = Sigma 3D
; printer_model = 
; printer_notes = 
; printer_settings_id = Sigma 3D
; printer_technology = FFF
; printer_variant = 
; printer_vendor = 
; raft_layers = 0
; remaining_times = 0
; resolution = 0
; retract_before_travel = 0.5
; retract_before_wipe = 0%
; retract_layer_change = 0
; retract_length = 0.8
; retract_length_toolchange = 10
; retract_lift = 0
; retract_lift_above = 0
; retract_lift_below = 0
; retract_restart_extra = 0
; retract_restart_extra_toolchange = 0
; retract_speed = 40
; seam_position = aligned
; silent_mode = 1
; single_extruder_multi_material = 0
; single_extruder_multi_material_priming = 1
; skirt_distance = 4
; skirt_height = 1
; skirts = 4
; slice_closing_radius = 0.049
; slowdown_below_layer_time = 5
; small_perimeter_speed = 20
; solid_infill_below_area = 5
; solid_infill_every_layers = 0
; solid_infill_extruder = 1
; solid_infill_extrusion_width = 0
; solid_infill_speed = 20
; spiral_vase = 0
; standby_temperature_delta = -5
; start_filament_gcode = "; Filament gcode\n"
; start_gcode = M561;Clear bed transforms\nG28 XY; Home X and Y axis\nM280 P3 S10 I1; BLTouch Pin down\nG1 X100 Y100; Go to 100\nG28 Z;\nG29 S1 ; Bed leveling with already recorded height map\nM280 P3 S90 I1; BLTouch pin up\n
; support_material = 0
; support_material_angle = 45
; support_material_auto = 0
; support_material_buildplate_only = 0
; support_material_contact_distance = 0.2
; support_material_enforce_layers = 0
; support_material_extruder = 1
; support_material_extrusion_width = 0
; support_material_interface_contact_loops = 0
; support_material_interface_extruder = 1
; support_material_interface_layers = 1
; support_material_interface_spacing = 0
; support_material_interface_speed = 100%
; support_material_pattern = rectilinear
; support_material_spacing = 3
; support_material_speed = 60
; support_material_synchronize_layers = 0
; support_material_threshold = 45
; support_material_with_sheath = 0
; support_material_xy_spacing = 50%
; temperature = 200
; template_custom_gcode = 
; thin_walls = 1
; threads = 8
; thumbnails = 
; toolchange_gcode = 
; top_fill_pattern = monotonic
; top_infill_extrusion_width = 0
; top_solid_infill_speed = 30
; top_solid_layers = 3
; top_solid_min_thickness = 0
; travel_speed = 90
; use_firmware_retraction = 0
; use_relative_e_distances = 1
; use_volumetric_e = 0
; variable_layer_height = 1
; wipe = 0
; wipe_into_infill = 0
; wipe_into_objects = 0
; wipe_tower = 0
; wipe_tower_bridging = 10
; wipe_tower_no_sparse_layers = 0
; wipe_tower_rotation_angle = 0
; wipe_tower_width = 60
; wipe_tower_x = 180
; wipe_tower_y = 140
; wiping_volumes_extruders = 70,70
; wiping_volumes_matrix = 0
; xy_size_compensation = 0
; z_offset = 0

I was wondering, if more people are willing to print this object and post a picture.

Hi,

This problem has been a huge challenge for me and I was wondering if anybody else had this problem.

I have observed that objects with certain features, like holes, modified the layer thickness at that layer. This effect is not very visible with organic shapes, like statues or figurines, but quite obvious for objects with straight walls. One object where this problem is very obvious is the XY-test object file from Make 2016/2017 3D Printer Test (https://www.thingiverse.com/thing:2071696/files) . Here's a picture demonstrating the problem (I've printed it at 120% scale, it made the problem more visible):

![

The leftmost picture is where the problem is most obvious. There is a very regular band whenever there is a hole (there is a second hole on the object but it isn't visible on the picture, however its artefact is). The opposite wall (second picture) has the same problem but it is inverted (it is as if there was a layer shift). However, when I look at the external walls (third and forth pictures), there is no layer shift at all (at least it isn't visible as prominently).

Now whenever I asked this question on other forums I got some suggestions about the belts not being tight enough or being too tight. I don't believe that's the problem, as the artefact is too regular and not equally visible on both sides. I don't think this is a temperature problem (there is no fluctuations on the hotend and the bed was turned off). The artifeact is visible on Prusa Slicer, Cura, and Simplify 3D (the pictures are forum Prusa Slicer version), so I don't think this is related to the slicers too (they all print the object the same way: Regular one sided movements on parts without the walls, and 180 degree returns at the holes. Interestingly no slicer tries to print the layers with the hole by moving stragiht, going past the hole by retracting and continuing from the other side of the hole. I wonder if the results would be different if they printer like this). The object itself looks very straight without artifacts when loaded to the slicers, so I don't think this is a problem with the object's design (one problem could be that there are 2 versions of this object, one with 0.8 mm thick walls and one with 1 mm thick walls, however the problem is visible on both of them, but slightly less prominent on 1 mm object). My extruder is calibrated (it is a standard BMG and I've performed the extruder calibration a few times).

I am out of ideas. Maybe this is a problem with all of the slicers, making some approximations, which become visible at certain parts. Maybe it is specific to Duet (I'd highly doubt it). Maybe it is a problem with how slicers calculate extrusion amount and it changes at each layer (so each layer's thickness is slightly different). Maybe it is a limitation of the FDM process itself.

Do you have any theoies/ideas? Have you ever tried to print this object?