The nozzle scratches the part
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Hi everybody,
I’m going to try explain my issue; first of all, some information regarding the machine and it’s config:
My machine is a BLV cube (Core XY) 310x310x600 with a Duet 2 Wifi. The heated plate is piloted by 2 drives.
The updated firmware is: 3.2.2
The panel isn’t updated at the moment and everything is directly piloted by my machintosh via the Duet Web Control 3.2.2.(Duet WiFi Server Version: 1.25)I finish the main mounting around 2 months ago and had begun to print.
An important information : The head is completely customised and is now running with a first nozzle (with external extruder) but the head is ready for running with a second nozzle. As I have some problems to make it run , I begun with a single nozzle.Now the main issue: the nozzle scratches the part and it’s impossible to finish a job. The first level is sometimes difficult to launch but I generally finish to launch it. After this first layer, as the printing continues, the nozzle begins to scratch the part until the PLA plugs the nozzle and after 3/4 layers the PLA stops feeding the nozzle and it’s finished…
I already tried many ways to solve the problem (feeding calibration,speed reducing, Z hop, avoid retracting,…)The last improvements done without real improvement: I changed the lead screws: now I install 2 screws TR8x2 to replace TR8x8 and multiply by 4 the resolution. Interesting but no result… I changed also the rigidity of the printing head. Also interesting on the paper but without result.
At the end I begin to be lost and would like to investigate the problem with more rigour… If you have other ideas, you’re welcome …
Below my config:
; 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 Apr 30 2021 20:09:39 GMT+0200 (CEST); General preferences
M80 ; Turns on the ATX power supply
G90 ; send absolute coordinates...
M83 ; ...but relative extruder moves
M550 P"RD Cube" ; set printer name
M669 K1 ; select CoreXY mode; Network
M552 S1 ; enable network
M586 P0 S1 ; enable HTTP
M586 P1 S0 ; disable FTP
M586 P2 S0 ; disable Telnet; Drives
M569 P0 S1 ; physical drive 0 goes forwards
M569 P1 S1 ; physical drive 1 goes forwards
M569 P2 S0 ; physical drive 2 goes backwards
M569 P3 S1 ; physical drive 3 goes forwards
M569 P4 S1 ; physical drive 4 goes forwards
M584 X0 Y1 Z2 E3:4 ; set drive mapping
M350 X16 Y16 Z16 E16:16 I1 ; configure microstepping with interpolation
M92 X200 Y200 Z1600 E425:425 ; OLD E405.18:405.18 ; Set steps per mm for Bondtech.
M566 X600 Y600 Z24 E300:300 ; Set maximum instantaneous speed changes (Jerk) (mm/min)
M203 X20000 Y20000 Z600 E2000:2000 ; Set maximum speeds (mm/min)
M201 X2000 Y2000 Z100 E5000:5000 ; Set accelerations (mm/s^2) (before X=Y=3000)
M906 X1600 Y1600 Z1600 E1600:1600 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout; Axis Limits
M208 X-23 Y-30 Z0 S1 ; set axis minima
M208 X315 Y315 Z665 S0 ; set axis maxima; Endstops
M574 X1 S1 P"xstop" ; configure active-high endstop for low end on X via pin xstop
M574 Y2 S1 P"ystop" ; configure active-high endstop for low end on Y via pin ystop
M574 Z1 S2 ; configure Z-probe endstop for low end on Z; Z-Probe
; OLD: M574 Z1 S2 P"probe.in" ; Set endstops controlled by probe
; OLD: M558 P1 C"zprobe.in" H5 F120 T6000 I0 R0.5 ; set Z probe type to unmodulated and the dive height + speeds
; OLD: G31 P500 X6.875 Y62.6 Z1.587 ; set Z probe trigger value, offset and trigger height
; OLD: M557 X15:300 Y40:280 S28.5:24 ; define mesh grid
M950 S0 C"exp.heater3" ; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" H5 F120 T6000 ; set Z probe type to bltouch and the dive height + speeds
G31 P25 X60 Y70 Z2.565 ; set Z probe trigger value, offset and trigger height
M557 X40:310 Y40:270 S27:23 ; define mesh grid; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B3950 ; 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 R2.429 C100:140 D5.5 S1.00 V0 B0 ; set process parameters for bed H0
M140 H0 ; map heated bed to heater 0
M143 H0 S100 ; set temperature limit for heater 0 to 100C
;Heater 0 model: heating rate 2.429, cooling time constant 140.0, dead time 5.50, max PWM 1.00, calibration voltage 0.0, mode PID
;Computed PID parameters: setpoint change: P13.4, I0.482, D51.4, load change: P13.4, I0.949, D51.4
M308 S1 P"e0temp" Y"thermistor" T100000 B4138 ; 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 B0 S1.00 ; disable bang-bang mode for heater and set PWM limit
M143 H1 S260 ; set temperature limit for heater 1 to 260C
M308 S2 P"e1temp" Y"thermistor" T100000 B4138 ; configure sensor 2 as thermistor on pin e1temp
M950 H2 C"e1heat" T2 ; create nozzle heater output on e0heat and map it to sensor 2
M307 H2 B0 S1.00 ; disable bang-bang mode for heater and set PWM limit
M143 H2 S260 ; set temperature limit for heater 2 to 260C; Fans
M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 F500 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 F500 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 F500 H2 T45 ; set fan 1 value. Thermostatic control is turned on; Tools
M563 P0 S"T0" D0 H1 F1 ; 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
M563 P1 S"T1" D1 H2 F2 ; define tool 1
G10 P1 X-30 Y0 Z0 ; set tool 1 axis offsets
G10 P1 R0 S0 ; set initial tool 1 active and standby temperatures to 0C; Automatic power saving
M911 S21 R22 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; Set voltage thresholds and actions to run on power loss; Custom settings are not defined
; Miscellaneous
T0 ; select first tool
;T1 ; select second tool
M575 P1 S1 B57600 ; enable support for PanelDue -
@redax27 At first glance, and with the limited information you've supplied, one possibility is that the steps per mm for the Z axis is incorrect. With the nozzle close to the build plate, send G91 to set relative moves, then send G1 Z50 or G1 Z100 to move the Z axis by 50mm or 100mm and measure how far it actually moves.
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@deckingman Thank you for your answer; I will try it (again) at home. I have already done it at the beginning of the commissioning and as I remember it was ok. I have 200 steps/rev; 2mm/rev; and micro stepping 1/16. I have:
M350…Z16
M92 … Z1600
I think it’s correct -
@redax27 That looks fine, providing your lead screws really are 2mm lead.
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@redax27 A few things to try:
- Try homing your Z, then moving it 100mm - double-check with a ruler that it actually has moved 100mm. Your maths for the z-steps seems right but if it only moves 50mm, you'll prove you've got something wrong somewhere.
- Have you calibrated your e-steps? If the Z is moving the right amount, then the other obvious thing is that you are pushing out too much plastic
- Have you got your slicer settings wrong (e.g. wrong filament diameter? using volumetric extrusion? etc)
I also notice that your hotend thermistors are still using the default value (B4318). It's probably worth trying to find out what the correct values are for the thermistor you are using just in case that means you are significantly out on temperature.
Home-built CoreXY, Duet Wifi, Chimera direct drive, 2x BMG, 300x300x300 build volume
i3 clone with a bunch of mods -
@deckingman Hi, I try this morning to move the Z 50mm and the bed moves exactly 50mm. I have no time enough to check separately each screw, I measured in front of the right screw, I will try this evening the left screw; maybe I have a problem on the second motor…
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@engikeneer Hi, I will check each proposition.
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It doesn’t seem to be the Z calibration (second motor to be checked to remove a problem on one of both motors.
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I have already calibrated the extrusion by measuring the effective length processed
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The thermistors settings could be also checked again. As I remember, I followed a procedure to set each thermistor PID, I could do it again.
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I will check on my slicer the extruding type. I don’t remember to change something…
Anyway, thank you for your suggestions !
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@engikeneer Sorry for this newbie question… do you know where to change volumetric settings in Cura? Regards
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@redax27 I'm not sure about volumetric settings in Cura, but it could be that the filament diameter is set incorrectly. If you use 1.75mm filament, but Cura is set to 3mm filament, you will get massive over-extrusion.
Ian
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@droftarts said in The nozzle scratches the part:
If you use 1.75mm filament, but Cura is set to 3mm filament, you will get massive over-extrusion.
I think it will be the other way around... in this case, you will have massive under-extrusion.
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@cosmowave Yes, you're right, thanks!
Ian
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@redax27 Can you post a picture of your first print? That might help us see if the problem is over-extrusion. If you can also post the gcode file, it may show if the gcode is sending commands it shouldn't.
Ian
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@droftarts First of all, thank you to participate to solve my problem!
See below a picture of a part aborted; We can see strange traces like that from the first layer. I attach also the G-code but it is too big; I post only the beginning of the file.
I note also frequently strange over-speeds...
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@droftarts:
Hi,
Did you have a little moment to see my file?
This evening, I try another print coming from another version of Cura on another computer.
It's worse and stops earlier after the first layer
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@redax27 Nothing obvious sticks out to me with your print file.
When you start a print, do you start the file with the build plate cold? In your print file it appears as if you home the printer first, and then preheat your bed. I recommend changing your Cura profile to either preheat the bed and nozzle before homing, or re-home after the build plate and nozzle temperatures are reached.
I ask because of this area (same as bottom right):
It looks as if the nozzle and build plate are coming closer together (or even the bed is not level/bent). This COULD happen if your bed, nozzle, frame, etc, are expanding as they increase in temperature. Although, 60°C isn't TOO hot. Could also be that your bed is not flat.
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@sebkritikel Hi,
Thank you for your answer; the reason why I do it like that is an accuracy measurement problem.
As I let the bed heat during the bl-touch measurement causes a big error (more than 0.5/0.6mm).
If I have no heating and no fans, in this case I have a good measurement and always the same.
I can maybe begin to heat and stop the heating only during the short measurement.
Do you think it's a good idea? The best way is to solve the measurement mistake, but I have no idea how to solve that.
Regards -
@redax27 The accuracy problem - do you mean you see a big difference in the height map when the bed is cool vs. when the bed is hot (for example, you measure when cold, then later measure when hot)? Or do you mean that the BL touch homing may vary/error by .5 / .6mm?
Do you do a height map? If so, can you upload one?
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@sebkritikel As you say, I think it's an interference when heating. If I do G30-S-1 alone or G30 S-1 with the heating, I have a big measurement difference (around 0,5/0,6). I will add B term as proposed to M558 . For information, see enclosed my map. I have done it by heating the bed @60°C and cut it during the process. It's not perfect because the bed cools down but better than nothing.
heightmap.csv -
@sebkritikel Hi, after some week-end tests, I go ahead but not completely cancelled my problem.
Adding B1 to M558 during measurement cycle is appropriate and cut the heating during measures.
After applying this new feature, G29 seems correct and the printing of the first layer is better. But after several layers the extruder forces again and stops the material feeding.
I begin to be really disappointed because it’s difficult to print something simple.
Below my last test. Could it be the atmosphere moisture?
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Below my last test.
Don’t know much about your printer, the filament you use and the parameters you apply to a print, but your "cabriolet" benchy reminds me of what I get from a (partially) clogged nozzle.
The potential reasons are manyfold and difficult to spot, maybe you can give us some hints:
- filament type (I assume: PLA?)
- wattage of the heater
- heater temperature
- nozzle diameter
- print speed
- retraction settings
- setup of your customised print head
The last item from my list is aimed at a possible heat-creep which may block the filament flow over time. That depends largely on the cooling of your hotend (fan1) and the retraction settings.
