After Z probing, print head smashing into bed
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@fcwilt Hi There, yes it reports the result of 2.47. I have done this numerous times and somehow its still not working...
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@gloomyandy That is correct, its a custom built machine with its own material holder on the top. All of these materials go through one nozzle (switching hotend)
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@Adam_Sw3 What was the result of positioning the tool so that the nozzle is just touching the bed? What is the Z reading when in that position?
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@Adam_Sw3 said in After Z probing, print head smashing into bed:
@fcwilt Hi There, yes it reports the result of 2.47. I have done this numerous times and somehow its still not working...
Thanks for checking it.
The code at the start of the print file looks correct.
One of the first things it does is a G28 to home all.
I assume homing works fine when done from the Dashboard?
Frederick
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@fcwilt Hi frederick, thanks for confirming, yes the homing works fine etc.
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@gloomyandy ermmm, you may have got me onto this issue, its reporting 7.2mm.
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@Adam_Sw3 said in After Z probing, print head smashing into bed:
you may have got me onto this issue, its reporting 7.2mm.
Do you have some code that is setting the Z offset of the tool?
Frederick
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@fcwilt Hi, i am using the duet reccomended way -> https://docs.duet3d.com/User_manual/Connecting_hardware/Z_probe_testing
The problem, i am having it seems, is that when I centre the nozzle and place it onto the bed after following this guide, it reports 4mm even though its technically zero (since the nozzle is touching)? I dont really understand whats going on here.
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@fcwilt It looks like the Z probe is 3.91mm away but the nozzle is touching the bed. I dont really understand...
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@Adam_Sw3 said in After Z probing, print head smashing into bed:
@fcwilt It looks like the Z probe is 3.91mm away but the nozzle is touching the bed. I dont really understand...
Do you have config-override.g file? If so did you check it's contents for something affecting the settings of the probe or tool?
What sort of Z probe are you using?
After setting the Z=0 Datum using G30 you should be able to move the nozzle so it is just touching the bed and the Z position should be shown as 0 or close to it.
Does it work that way?
Frederick
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@fcwilt I do but it is empty. I am using a inductance sensor. I have done that G30 command proccess. But turned out the problem was that the bed wasnt level, anyways I used true bed levelling that sorted this. I repeated the proccess again, yet when the nozzle is touching the build plate it reads a z position of 1.4mm. Which i dont really understand?
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@fcwilt Would increasing my Z offset bring it further away from the bed and then from there, i could baby step it down onto the bed? Or would it be the inverse (decreasing Z offset)
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Can you share your homing files and bed.g and any other macros you're using for leveling?
What firmware version?
@Adam_Sw3 said in After Z probing, print head smashing into bed:
M92 X80.00 Y80.00 Z1066.67
How did you determine those steps per mm for Z? It seems a strange value.
For a leadscrew z axis the formula for steps per mm is as follows.
Z_steps_per_mm = (motor_steps_per_rev * driver_microstep) / screw_lead
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@Phaedrux hello Phaedrux! yes certainly, i will supply these in the morning (GMT 08:00) i will share these. I got these z steps per mm using the prusa calculator. I am using this Lead screw https://uk.rs-online.com/web/p/lead-screws/8625281?gb=s i also checked with verniers ie down 25mm etc.
Thank you.
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@Adam_Sw3 said in After Z probing, print head smashing into bed:
@fcwilt Would increasing my Z offset bring it further away from the bed and then from there, i could baby step it down onto the bed? Or would it be the inverse (decreasing Z offset)
That would be putting a bandage on the symptoms and hiding the real problem.
Hang in there - we will sort it.
Frederick
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Hi Phaedrux, my bed.g is here
; bed.g ; called to perform automatic bed compensation via G32 ; ; generated by RepRapFirmware Configuration Tool v3.3.14 on Sat Oct 29 2022 18:08:10 GMT+0100 (British Summer Time) G28 ; home G30 P0 X0 Y440 Z-99999 ; probe near a leadscrew G30 P1 X570 Y440 Z-99999 ; probe near a leadscrew G30 P2 X290 Y10 Z-99999 S3 ; probe near a leadscrew and calibrate 3 motors ;M561 ; clear any bed transform ;G29 ; probe the bed and enable compensation
Home all
; homeall.g ; called to home all axes ; ; generated by RepRapFirmware Configuration Tool v3.3.14 on Sat Oct 29 2022 18:08:10 GMT+0100 (British Summer Time) G91 ; relative positioning G1 H2 Z5 F6000 ; lift Z relative to current position G1 H1 X-555 Y-415 F1800 ; move quickly to X or Y endstop and stop there (first pass) G1 H1 X-555 ; home X axis G1 H1 Y-415 ; home Y axis G1 X5 Y5 F6000 ; go back a few mm G1 H1 X-555 F360 ; move slowly to X axis endstop once more (second pass) G1 H1 Y-415 ; then move slowly to Y axis endstop G90 ; absolute positioning G1 X-20 Y10 F6000 ; go to first bed probe point and home Z G30 ; home Z by probing the bed ; Uncomment the following lines to lift Z after probing ;G91 ; relative positioning ;G1 Z5 F100 ; lift Z relative to current position ;G90 ; absolute positioning
Home X
; homex.g ; called to home the X axis ; ; generated by RepRapFirmware Configuration Tool v3.3.14 on Sat Oct 29 2022 18:08:10 GMT+0100 (British Summer Time) G91 ; relative positioning G1 H2 Z5 F6000 ; lift Z relative to current position G1 H1 X-555 F1800 ; move quickly to X axis endstop and stop there (first pass) G1 X5 F6000 ; go back a few mm G1 H1 X-555 F360 ; move slowly to X axis endstop once more (second pass) G1 H2 Z-5 F6000 ; lower Z again G90 ; absolute positioning
Home Y
; homey.g ; called to home the Y axis ; ; generated by RepRapFirmware Configuration Tool v3.3.14 on Sat Oct 29 2022 18:08:10 GMT+0100 (British Summer Time) G91 ; relative positioning G1 H2 Z5 F6000 ; lift Z relative to current position G1 H1 Y-415 F1800 ; move quickly to Y axis endstop and stop there (first pass) G1 Y5 F6000 ; go back a few mm G1 H1 Y-415 F360 ; move slowly to Y axis endstop once more (second pass) G1 H2 Z-5 F6000 ; lower Z again G90 ; absolute positioning
Home Z
; homez.g ; called to home the Z axis ; ; generated by RepRapFirmware Configuration Tool v3.3.14 on Sat Oct 29 2022 18:08:10 GMT+0100 (British Summer Time) G91 ; relative positioning G1 H2 Z5 F6000 ; lift Z relative to current position G90 ; absolute positioning G1 X-20 Y10 F6000 ; go to first probe point G30 ; home Z by probing the bed ; Uncomment the following lines to lift Z after probing ;G91 ; relative positioning ;G1 Z5 F100 ; lift Z relative to current position ;G90 ; absolute positioning
Current firmware is
FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 3.4.4 ELECTRONICS: Duet WiFi 1.02 or later + DueX5 FIRMWARE_DATE: 2022-10-20 16:17:41 -
@fcwilt Thanks Frederick! Its people like you that really go under appreciated in these forums, thanks for your help. I have replied to phaedrux below so we shall see what he says.
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You mentioned that you use an inductance sensor.
In your probe configuration you have chosen type P1. Does you sensor actually have an analog output like a "smart IR probe"?
I've used many inductive sensors and I have always specified type P8, since the output of the probe is either "on" or "off".
I also would like to share with you what steps I perform when starting a print and why I do them.
But I don't have the time right now - it's 5.00 AM.
Doing the needed things in the correct order at the start of a print is important.
Frederick
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@fcwilt Hi Fredrick, my inductance sensor is similar to here https://www.aliexpress.com/item/1005004853709100.html?spm=a2g0o.productlist.main.33.60c8l3fwl3fwqS&algo_pvid=6f2ef3f2-1dd9-4b63-a7bd-bb78c1f5cfd8&algo_exp_id=6f2ef3f2-1dd9-4b63-a7bd-bb78c1f5cfd8-16&pdp_npi=4%40dis!GBP!6.68!6.68!!!7.89!!%4021038eda16964986241754812e39f3!12000030753506738!sea!UK!2004704503!&curPageLogUid=BWGfMQ4DwVrl
it has 3 leads, power is connected to my fan header (always on) so i put my z probe signal to my z probe signal header. what does p8 specify?
Thank you.
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It is fairly typical of Chinese units - a bit short on specs. It says it has fast response but I didn't see a frequency spec. Higher frequency normal yields faster response.
I usually get my units from here:
They have a good selection - for example they list 35 4mm units. And they usually provide full specs. They tend to be more expensive.
Probe type 8 just specifies that the probe sends an signal that is either ON or OFF, which is what these types of probes typically do.
Frederick