Bltouch giving me bogus height map
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@fcwilt said in Bltouch giving me bogus height map:
it's strange they don't seem to have provided for it.
I think the idea is get it close enough and let the mesh take care of the rest.
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@Phaedrux said in Bltouch giving me bogus height map:
I think the idea is get it close enough and let the mesh take care of the rest.
That is certainly possible.
Frederick
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@ageis I’d guess what’s happening is that you’re driving the Z axis too fast during mesh levelling, and it’s skipping. I can’t think of any other reason you’d get a bed shape like that, and might also explain why the Z offset keeps changing. But I can’t see what your max/min numbers are, and you haven’t posted your config.g, so it’s hard to tell what is going on.
Edit: can you also post the bed csv file as well?
Ian
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@droftarts
Here is the config.g; Configuration file for Duet WiFi (firmware version 3.3) ; executed by the firmware on start-up ; ; generated by RepRapFirmware Configuration Tool v3.3.16 on Sun Jul 23 2023 20:00:34 GMT+0100 (British Summer Time) ; General preferences G90 ; send absolute coordinates... M83 ; ...but relative extruder moves M550 P"prusa" ; set printer name ; Network M552 P0.0.0.0 S1 ; enable network and acquire dynamic address via DHCP 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 S1 ; physical drive 2 goes forwards M569 P3 S1 ; physical drive 3 goes forwards M584 X0 Y1 Z2 E3 ; set drive mapping M350 X16 Y16 Z16 E16 I1 ; configure microstepping with interpolation M92 X98.52 Y100.00 Z400.00 E161.3 ; set steps per mm M566 X900.00 Y900.00 Z12.00 E120.00 ; set maximum instantaneous speed changes (mm/min) M203 X6000.00 Y6000.00 Z1000.00 E1200.00 ; set maximum speeds (mm/min) M201 X500.00 Y20.00 Z400.00 E250.00 ; set accelerations (mm/s^2) M906 X1300 Y800 Z800 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 X250 Y190 Z210 S0 ; set axis maxima ; Endstops M574 X1 S1 P"xstop" ; configure switch-type (e.g. microswitch) endstop for low end on X via pin xstop M574 Y1 S1 P"ystop" ; configure switch-type (e.g. microswitch) endstop for low end on Y via pin ystop M574 Z1 S2 ; configure Z-probe endstop for low end on Z ; Z-Probe ;M558 P8 C"zprobe.in" H10 F120 T6000 ; set Z probe type to unmodulated and the dive height + speeds M558 P9 C"^zprobe.in" H15 F120 T6000 M950 S0 C"exp.heater3" ;G31 P500 X22 Y10 Z120.1 0; set Z probe trigger value, offset and trigger height G31 P500 X30 Y10 Z1.9;trigger value, offset and trigger height M557 X40:235 Y0:190 S10 ; 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 B1 S1.00 ; enable bang-bang mode for the bed heater and set PWM limit M307 H0 R0.268 K0.283:0.000 D13.25 E1.35 S1.00 B0 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 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 S280 ; set temperature limit for heater 1 to 280C ; 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 ; Tools M563 P0 D0 H1 F0 ; 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 T0I have tried to level the bed using a boat level then realigning the x axis with my digital calipers. then recalibrating the z height as @fcwilt dvised. However the resultant height map is still bogus.
There is still a slope that is saying the left hand side is lower than the right.
However the booat level says it's level.Thanks for the help everyone has given me. Wouldn't of known what to do otherwise.
HeightMap.csv
https://drive.google.com/file/d/1ga-Y2M7HSUh-w4UNnMVq5N1pdo4arfwv/view?usp=sharing -
I think I mentioned that what you are trying to do is get the bed to be perpendicular to the Z axis and parallel to the XY axes plane.
This is actually called tramming. Making the bed level using a actual level may not give the desired results.
Imagine tilting the entire printer, say, 45 degrees to the right. Then using an actual level on the bed is clearly going to say the bed is way out of level - but it can still be perpendicular to the Z axis.
On a printer with easily accessible "thumb screws" that adjust the bed there is a fairly simple procedure you can run on the printer itself which probes the bed near the thumb screws and reports how much adjustment is needed for each.
But that is not going to work for you.
It seems you are going to have the tram the bed as best you can and create a height map to see how it turned out. You may have to repeat the process several times.
Perhaps someone with a machine like yours will chime in.
Frederick
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@fcwilt
I am beginning to think perhaps I should of got it built by Prusa.
I have learnt the hard way that building a 3d printer isn't just bolting it together. -
@ageis said in Bltouch giving me bogus height map:
@fcwilt
I am beginning to think perhaps I should of got it built by Prusa.
I have learnt the hard way that building a 3d printer isn't just bolting it together.I did not know Prusa sold kits.
Building a printer needs a lot of attention to detail to get first rate results.
If, like me, you tend to have a slight case of OCD it actually helps.
Frederick
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@ageis said in Bltouch giving me bogus height map:
Looking at your bed heightmap, it isn't that bad; it's only -1.84mm to +0.58mm at the extremes. This quite possibly looks okay with a level, which is really not the best way of levelling a bed.
I'm not sure what version Prusa i3 you have (Mk2?), but Prusa i3 printers usually have a built-in calibration routine. But as you've removed the Prusa electronics and added a Duet, you don't have access to this. However, you can still do the same thing manually, and later add a macro to do it automatically on the Duet. For the Prusa instructions, see https://help.prusa3d.com/article/xyz-calibration-mk2-s_112396
This starts with moving the X axis to the top, so it hits the top of the Z axis on both sides. You can do this manually, by jogging the Z axis until the X axis is just at the top. Then send
M18to disable the motors. Then you can turn each leadscrew by hand (slowly, you don't want to destroy the stepper motor driver by spinning the motor fast) individually until the X axis is touching the top of the Z axis on both sides. This should square the X axis to the Z axis.With the X axis square, you now need to square the bed to the X axis. Jog the X axis down (ie move down in Z) until the nozzle is a little above the bed. Move the nozzle to the four corners of the bed making sure you don't actually hit the bed with the nozzle. The idea here is to adjust the bed so it is the same distance from the nozzle at the four corners, or as close as it can be.
Then run bed mesh and see what kind of mesh you get.
However, before that, your acceleration settings look a bit odd:
M201 X500.00 Y20.00 Z400.00 E250.00
Y is set very low, and is probably causing the bed to move slowly, while Z is quite high for a leadscrew axis, and might possibly cause it to miss steps. The RRF config tool usually suggests these quite conservative numbers:
M201 X500.00 Y500.00 Z20.00 E250.00My bedslinger has higher acceleration on X and Y, but Z is the same. They are just not designed to move very fast in Z!
Ian
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@droftarts
I don'tknow about the acceleration settings. Maybe i edited themby accident at some point.I have a problem with squaring the bed to the x axis. The upper right hand corner appears to be higher than the lower right hand corner.
So I squared up the x axis with z then went down till the nozzle was 0.4mm above the bed. IT didn't hit the bed when the nozzle was in the lower left or lower right corner. But the gap disappeared when I moved to the top right hand corner.
HOw is this possible? I haven't built it correctly then lol.
The direction of the slope also keeps changing. It's really weird. If you look at the last height map it slopes right to left. However the latest height map slopes from left to right.
Why is this
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@ageis #banging his head against the wall
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Do you have any bright ideas why the back of the print can be higher than the front of the printer? driving me insane. I won't be recommending Prusa printers to anyone.
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@ageis I asked before; what version of Prusa i3 do you have? It says on the bed, usually. I think you have a Mk1 or Mk2 of some sort, rather than a Mk3.
Generally, Prusa i3 printers don't have adjustable beds. The heated bed bolts onto a frame, the frame sits on the Y axis linear rods, and the Y axis bolts to the big square Z axis. If you assemble it carefully, on a flat table, it should end up pretty square. The X axis is set square by running it to the top of the Z axis, and any variation, which should be only a few tenths of a mm, can be fixed using mesh bed levelling.
If your bed is a long way out (ie more than 1mm), something has gone wrong in the assembly; possibly the bed carrier is bent/warped, or something else is not straight. It's also possible that your printed parts (some of which don't look that great) are throwing it off. Go back and check through the instructions of Y axis assembly, and connecting the Z to the Y axis.
Post your current bed mesh, either a picture (make sure we can see the min/max/rms data on the right side) or the heightmap.csv, so we can see how it's changed. (By the way, no need to use Google Drive to store pictures, you can upload them in your post on the forum.)
Ian
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@droftarts
Sorry I forgot to tell you it's a Prusa MK2S
I ave tried the tramming process using my feeler gauage as reference. However I still get a bogus height map. Now it's has a little mountain in the top right corner.So I have home all axis then used dwc to move to each of the four corner. the back two corners are now lower than the front two.
I have order some springs from Amazon. I will try with the springs tomorrow.
