Setting the Z probe is mission impossible

I am working under a 20W Osram Dulux EL Longlife light bulb and without any other light source available - so my room withouth the bulb wuld be pitch black!
However, the Z probe keeps giving me variable values.

At the beginning, the max value @1mm from the bed was 647. I left it running like that (ATX power OFF) for about half an hour, only to see that the value droped to 637 (without me moving or touching anything, and without any other light source).

Then I turned the ATX power on, and the value jumped to 639 and started moving about between 638 and 639.

In the meantime, while I was trying something else for the 100th time, the value jumped to 670 and is moving about 668 - 674, and I am working in a room with NO OTHER LIGHT SOURCE but the flourescent light bulb.

How in the hell am I suppose to get the value for the Z probe when it keeps changing??

ps before anyone asks, yes, I have DC42s sensor kit, but in order to install it I have to print something first and that I cant do because I cant get the Z probe value straight so I could move on to the bed compensation.

EDIT: I have also noticed that the Z probe value is more steady when the ATX power is turned off, the value changes much much rarely and only between 2 numbers (now 676-675)

Edited 3 time(s). Last edit at 04/27/2014 12:17PM by Sardi.

Set your bed level mechanically as good as possible. Zero the z axis manually in the middle area, near 100,100 using a slip of paper under the nozzle, make sure there is no filament sticking out or do it hot.

Then print your items, do not use any bed compensation.

Then fit the probe and forget all worries as it really does work well.

Have you got the aluminium bed support plate? If so you should not need compensation anyway, this also greatly extends the z axis screw and nut life.

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

Quote
Sardi
How in the hell am I suppose to get the value for the Z probe when it keeps changing??

ps before anyone asks, yes, I have DC42s sensor kit, but in order to install it I have to print something first and that I cant do because I cant get the Z probe value straight so I could move on to the bed compensation.

LOLZ!

forget about auto probing for a moment, move the nozzle to the middle of the bed, lower the nozzle so it lightly grips a piece of paper, then set the Z zero manually by sending "G92 Z0" - and setting the first layer a bit higher will help if you bed is a bit out of wack, but if it's a small print it won't matter anyway

Erik

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Davek0974
..Have you got the aluminium bed support plate? If so you should not need compensation anyway, this also greatly extends the z axis screw and nut life.

highly agree - also get the x-axis in alu, it will make your life a lot easier

..or at least do the Q & D fix that anyone can do, no extra material needed
[forums.reprap.org]

Erik

I replace all incan lamp with osram LED lamp direct replacement.
It give more light generate less heat and consume less energy. Btw. No ir emitted to
interfere the ir probe. I still using the supplied IR probe which is IMO is quite accurate.

Quote
Sardi
In the meantime, while I was trying something else for the 100th time, the value jumped to 670 and is moving about 668 - 674, and I am working in a room with NO OTHER LIGHT SOURCE but the flourescent light bulb.
...

EDIT: I have also noticed that the Z probe value is more steady when the ATX power is turned off, the value changes much much rarely and only between 2 numbers (now 676-675)

It's not a problem if the Z-probe value moves between 668 and 674. Such a small change corresponds to a very tiny fraction of a mm and will not significantly affect the height accuracy.

Yes, the Z probe value is more stable with the ATX power off. The reason is the on-board switching regulator induces noise in the wiring. It can be reduced by modifying the wiring as I have described here [forums.reprap.org]. But I don't think this is really necessary if you are calibrating with G31 readings above about 500. However, if I do another revision of my sensor board then I'm going to look at using digital communication instead of analog, to avoid this sort of interference.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks guys for the suggestions.

But right now the bed is not my enemy. I have managed to set a value for the Z probe in the middle of the bed, and have started printing, but something happened and after just a couple of circles the filament stoped flowing from the nozzle.

The extruder was working, bud started to kick in place as the filament got hard in the nozzle and the extruder couldnt push it anywhere, and I have no ide why that happened all of a sudden.

I am using the PLA provided with the kit, and the temperature was set to 200C.

The above is good advice... Level that bed and forget compensation. It's easier, and so much better.. I used a 3mm composit ally/plastic board to stiffen my sub-bed, then mounted that on top of the bit of crud MDF that was supplied as it had the cut outs for aligning the bed. I chopped the big holes out with a wood chisel. I also use 4mm Red Float Glass which helps the probe. Normaly I find, that the probe will work fine for me, and I can get respetable probe settings.

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Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

Quote
Sardi
Thanks guys for the suggestions.

But right now the bed is not my enemy. I have managed to set a value for the Z probe in the middle of the bed, and have started printing, but something happened and after just a couple of circles the filament stoped flowing from the nozzle.

The extruder was working, bud started to kick in place as the filament got hard in the nozzle and the extruder couldnt push it anywhere, and I have no ide why that happened all of a sudden.

I am using the PLA provided with the kit, and the temperature was set to 200C.

I suspect that either your hotend thermistor or heater connection is loose and became disconnected during printing.

Dave
(#106)

I Agee... I want to make my first print but can't get past this and the bed compensation... Help

Hmmmmmmmmmmmmmm I stopped using a probe totaly, a few weeks ago... It was one of my better choices....
Now I have major problems with that stupid connector on the HotEnd.... My wire cutters are coming out to play tomorrow.....

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Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

hihihihihi the wire cutters have been active, and a new connector fitted on the HotEnd. It's made a surprising differance. Now I can see the HotEnd LED Dimming and Brightening as the Firmwares working away, and my No.1 Fan is working properly. Looking forward to seeing the results from the test print I'm running now. Also, because of having the HotEnd off, I had to re-adjust the Z axis microswitch, and the got the tripping point down to -0.6mm which is another bonus.

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Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

Quote
Ecko
I Agee... I want to make my first print but can't get past this and the bed compensation... Help

Hi Ecko

You don't have to use the probe, you can do the manual bed compensation instead, and when you get to printing, zero the nozzle manually on a piece of paper

You could leave the probe for later, it's important to get to first print IMHO

You may also want to read this:
[forums.reprap.org]

[forums.reprap.org]

Erik

I agree 168. I have just levelled the bed (as much as I can) but using the web interface is a pain. It's better using pronterface - I just have issues printing with this... There are some fields that are updated in the web interface like z probe levels that aren't present in pronterface... In a nutshell - it's getting a little frustrating.

I will have a play tonight and update on progress. I really really want my first print! Been trying to set the bed compensation for a week now. I set z0 using the arduino IDE- print using pronterface and the nozzle hovers 10mm off the bed..... For the circle test print (frustrating).

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Ecko
... but using the web interface is a pain. It's better using pronterface...

Hi Ecko, why do you find using the web interface a pain? I think most of us have the opposite experience.

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I set z0 using the arduino IDE- print using pronterface and the nozzle hovers 10mm off the bed..... For the circle test print (frustrating).

The circle test print does not move Z at all, so I'm puzzled that you are saying it hovers 10mm off the bed. And why are you using Arduino IDE to set z0, rather than Pronterface or the web interface?

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

circle.g first 4 lines:
G1 F2000
G28
G1 Z5
G1 X180 Y100
G1 X179.96 Y102.525

So it homes all axes (using the probe), then moves up 5mm. If the probe doesn't get the right signal, it will move up 5mm. So both of those make 10mm.

In Pronterface, you can check the probe reading with G31. You can check the axis position with M114.

Ian
RepRapPro tech support

My mistake, I see that you've changed circle.g (on 14 Jan) since I downloaded it.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42

Quote
Ecko
... but using the web interface is a pain. It's better using pronterface...

Hi Ecko, why do you find using the web interface a pain? I think most of us have the opposite experience.

Ecko, if you are using the old default web interface, that one truly is a pain to use. If that is the case, get a newer version (with iamburny's and dc42's modifications) and everything will seem a lot better.

Quote
Ecko
I agree 168. I have just levelled the bed (as much as I can) but using the web interface is a pain. It's better using pronterface - I just have issues printing with this... There are some fields that are updated in the web interface like z probe levels that aren't present in pronterface... In a nutshell - it's getting a little frustrating..

Never have tried the web interface, used pronterface since day one, has never failed and is all I need for now

Erik