Best surface for IR probe accuracy

[dc42]

@stewwy, the wavelength is 850nm.

[Leblond]

Good evening to everyone
I have the problem of the printing plate that I can not level it with the mini ir sensor, at room temperature all the flatness of the plate is there, at 110 degrees I find it very high in the middle.
Well my situation is that after a two-month standstill to wait for an opaque black prinbite "more or less opaque ..", I bought it because having taken a while ago an IR I wanted to make a leap of quality but so 'has not been, and I continue to have problems of flatness', here I leave you the configuration of my Cartesian printer, which is a geeetech i3 pro b transformed to 24v e3dV6.1 and titan that mounts a nema 17 thin on extruder, the engines x, y, z are nema 17 of the quimat model 17hd48002h-22b, duet wifi "the only thing that so far has not given me the slightest problem"

Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
Firmware Electronics: Duet WiFi 1.02 or later
Firmware Version: 2.02RC3(RTOS) (2018-10-17b2)
WiFi Server Version: 1.21
Web Interface Version: 1.22.4-b1

Config:

; Configuration file for Duet WiFi (firmware version 1.21)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool on Sat Oct 06 2018 20:36:03 GMT+0200 (Ora legale dell’Europa centrale)

; General preferences
G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves

; Network
M550 PLanzet 3D ; Set machine name
M552 S1 ; Enable network
M587 S"FRITZ!BOX 3390" P"67443721948076126438" ; Configure access point. You can delete this line once connected
M586 P0 S1 ; Enable HTTP
M586 P1 S0 ; Disable FTP
M586 P2 S0 ; Disable Telnet

; Drives
M569 P0 S1 ; Drive 0 goes forwards
M569 P1 S1 ; Drive 1 goes forwards
M569 P2 S0 ; Drive 2 goes backwards
M569 P3 S1 ; Drive 3 goes forwards
M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
M92 X80.24 Y80.46 Z400 E413 ; Set steps per mm
M566 X1000 Y1000 Z200 E400 ; Set maximum instantaneous speed changes (mm/min)
M203 X6000 Y6000 Z420 E6000 ; Set maximum speeds (mm/min)
M201 X1000 Y1000 Z1000 E1000 ; Set accelerations (mm/s^2)
M906 X1000 Y1000 Z1000 E800 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1 ; Set axis minima
M208 X210 Y200 Z160 S0 ; Set axis maxima

; Endstops
M574 X1 Y1 S1 ; Set active high endstops

; Z-Probe
M574 Z1 S2 ; Set endstops controlled by probe
M558 P1 H5 F400 T8000 ; Set Z probe type to switch and the dive height + speeds
G31 P500 X-10 Y0 Z0 ; Set Z probe trigger value, offset and trigger height
M556 S0 X0 Y0 Z0 ; Set orthogonal axis compensation parameters
M557 X20:200 Y10:190 S56 ; Define mesh grid

; Heaters
M307 H0 B0 S1.00 ; Disable bang-bang mode for the bed heater and set PWM limit
M305 P0 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 0
M143 H0 S150 ; Set temperature limit for heater 0 to 120C
M305 P1 T100000 B4725 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 1
M143 H1 S280 ; Set temperature limit for heater 1 to 280C

; Fans
M106 P0 S1 I0 F500 H1 T50 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P1 S1 I0 F500 H1 T45 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P2 S1 I0 F500 H1 T45 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

; Tools
M563 P0 D0 H1 ; 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

; Automatic power saving
M911 S10 R11 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 configured

; Miscellaneous
M501

Bed:
; bed.g
; called to perform automatic bed compensation via G32
;
; generated by RepRapFirmware Configuration Tool on Sat Oct 06 2018 20:36:03 GMT+0200 (Ora legale dell’Europa centrale)
M561 ; clear any bed transform
;G29 S2
; Probe the bed at 5 points
G30 P0 X10 Y10 H0 Z-99999
G30 P1 X10 Y190 H0 Z-99999
G30 P2 X200 Y190 H0 Z-99999
G30 P3 X200 Y10 H0 Z-99999
G30 P4 X110 Y100 H0 Z-99999 S5
;G29 S1

[Leblond]

some idea?

[RCarlyle]

@leblond if it’s flat when cold and high in the middle when hot, the problem is probably a physical warping of your build plate from differential thermal expansion. Can you check that with a straight edge with a flashlight behind it?

What’s the physical construction of your bed stack?

Does running auto level with the bed hot change anything?

[dc42]

@leblond, can you run mesh bed compensation and publish the height map here?

[Leblond]

willingly, only if I knew how to do it

[Leblond]

un attimo

[Leblond]

RepRapFirmware height map file v2 generated at 2018-10-21 22:56, mean error 0.222, deviation 0.150
xmin,xmax,ymin,ymax,radius,xspacing,yspacing,xnum,ynum
20.00,200.00,10.00,190.00,-1.00,56.00,56.00,4,4
0.040, 0.240, 0.070, -0.070
0.207, 0.390, 0.295, 0.072
0.370, 0.468, 0.368, 0.135
0.153, 0.343, 0.357, 0.112
I wanted to calibrate it as hot as the problem can not be removed

[Leblond]

@RCarlyle
the building is 220x220x160
2mm heated aluminum platethe building is 220x220x160
2mm heated aluminum plate

[dc42]

@leblond said in Best surface for IR probe accuracy:

RepRapFirmware height map file v2 generated at 2018-10-21 22:56, mean error 0.222, deviation 0.150
xmin,xmax,ymin,ymax,radius,xspacing,yspacing,xnum,ynum
20.00,200.00,10.00,190.00,-1.00,56.00,56.00,4,4
0.040, 0.240, 0.070, -0.070
0.207, 0.390, 0.295, 0.072
0.370, 0.468, 0.368, 0.135
0.153, 0.343, 0.357, 0.112

I think the IR sensor is giving reasonably good readings, although it would be easier to tell if you reduced the mesh spacing to 28mm or lower.

[Leblond]

@ dc42 do you talk about mesh spacing?
             I had to make a 3x3 grid

1 to find the center of the bed

2 if I did a spacing of 20mm I had changes from -2 to +2 +/-

since I have the sensor, the only printing base that has improved and 'that arrived yesterday of the printbite, but I continue to have these changes, tonight when I come back from work I try to recalibrate it hot and post' results, if you need 'of data then PLEASE speak to you normally, unfortunately I am not an engineer with a hat like you, but a humble worker, but I'm getting better ... thanks for the understanding and good work.

[Leblond]

Good evening to everyone
Well as promised I tried to calibrate the print plate to 110 and these three images show the result.
image 1: car bed not calibrated
image 2: calibrated car bed
image 3: mesh

[Edkirk]

I have been using the heated beds from E3D, the older big box bed and recently their 120 volt high temperature bed. I painted the underside of the glass with white high temperature spray paint from McMaster Carr. initially to increase the visibility of the print over the black heated bed surface. This has been ideal with the IR Probe, I left the outer 10mm unpainted and the LED turns off when the sensor passes over the unpainted portion above the black. So the white paint does improve the sensor accuracy. Works great.

[Edkirk]

I forgot to mention the nozzle crashed into the glass when I installed the new unpainted bed.

[dc42]

@leblond said in Best surface for IR probe accuracy:

@ dc42 do you talk about mesh spacing?

Yes, I meant use a mesh with smaller spacing/more points, e.g. 7x7 or 9x9.

[dc42]

@edkirk said in Best surface for IR probe accuracy:

I painted the underside of the glass with white high temperature spray paint from McMaster Carr.

If you are using our mini differential IR probe, that's completely the wrong thing to. The correct thing (as described in the fitting instructions) is to paint the back surface matt black. This is to make the reflection from the front surface of the glass stronger than the reflection from the back.

If you are using some other type of IR sensor then this probably doesn't apply and I can't help.

[Edkirk]

I am using your mini IR probe, absolutely the best. I had painted the underside of my first E3D glass white because I didn’t like the black, couldn’t see how the first layer was going down. At that time I was using a touch prob, it never worked very well. The high temperature white spray paint is very flat or dull, goes on rough. I cure the paint by laying it on the heated bed paint side up for several hours at the highest temperature I am comfortable with. then rub the dust off with a cloth between coats. My comment is just to provide feedback on an accidental discovery that works great.

[Leblond]

Forgive me, if I have not made myself alive before.
@dc42 I'll settle you as soon as I finish my experiment and post my data.
As you well remember "let me give you some .." you asked me about the mesh, now since the aluminum base for all the efforts you make .. it expands too much in height since it is stopped in the 4 corners for leveling , so I thought to use a glass plate ultra-base and put it on the sheet of prinbite, I will try 'to calibrate cold for, and then hot starting from 100 degrees celsius, and then get to 120, according to you it will work '?, now ban to ciancie and below with the work ... a later

[Leblond]

Here I am

@dc42 What do you say? the first photo is with G32, the second one with G29 mesh 20x20

[dc42]

The only reason the first one looks better is that it has only 5 points. It looks to me that the bed is flat, so I suggest you use either no bed compensation at all, or a 2x2 mesh, or a 3x3 mesh.