Testing Resolution / accuracy , Your results wanted! Z Probe Results
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so for me contact to contact above 500mm/min we start getting out of a nice range.
~Russ
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@Russ:
I will try to find the time to do an electrical contact test on this printer for a baseline. Plus looking at the data for microswitches, of which some did very well, the issue here is you are deploying them by servo, in the real world? So how do they do on repeatability from one run to the next? This is the reason I love piezo, its permanently mounted. If you attach a microswitch to probe then remove it afterwards, how repeatable is that between runs?
Maybe add a third test probe, home, probe, home etc…
yeah i wanted to do a home probe home probe test but that is i think for another day… because then your adding the tolerance of your homing switches. its more than i wanted to test at first.
If we all set up a contact contact and got a 0 deviation... we could then test the accuracy of our Homing... ( however i cant even get a 0 deviation even when running very slow)
if anyone has a servo controlled micro switch probe do please test. i think that we will find a lot of error in that.
for me tho i want a direct switch with the hot end. like your piezo system.there are already deigns out there like this.
https://www.youtube.com/watch?v=e119OXzkk7s
but, like i said with a micro switch you have to back it off x amount and that means that you need a part that moves a lot more than lets say your piezo system. this means there is more chance for error and your nozzle moving around while printing.there are micro switches that dont need much movement, but nothing like a FSR or the piezo system. where you can basically hard mount everything but know that you are measuring this force…
dose anyone own a seemecnc rig with the accelerator probe??? That i do want data for!!
~Russ
It would be nice to have an endstop repeatability test of some sort? Any ideas?
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@Russ:
Separating probe accuracy from printer build accuracy is tough to do. On my delta I'm fighting a mechanical issue right now which makes any sort of probe repeatability tests futile, as it quickly falls into the noise of the printer itself (I have a bearing or something that's gone out, makes a grinding noise during some moves, but for the life of me I can't track it down yet)
In addition, if you're probing two points at any distance apart, then you're actually adding your current calibration accuracy into the probe data, since you're really comparing against the currently calculated plane.
This is correct. this is why i wanted only a single point. even when moving around the point is still 0,0
do you have a motor bearing bearing out? take off the tension and wiggle the shaft… or turn it and see if you hear and noises??
even with your error, can you run the tests, just for fun then again after you find the problem. just to see if it even changed anything?
I will not add the data till after you find the problem, but just for fun sounds interesting to see how much it is effecting your setup ?
~Russ
My printer is partially dismantled to find the source of the grinding sound, and to do some work on my piezo probe setup. Once I find the time to work on it again I'll try and run your tests.
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Just been thinking about the endstop test. The issue is reference points isn't it? Since the endstop is the reference point for the axis the only way to test it would be to create a hard limit somewhere, for example with rails, clamping something onto the rail say 5-10cm from the endstop, then moving the carriage/s manually to sit against the hard clamp point, then homing and then move back under power to the hard stop noting the distance travelled. Repeat this process 20-30 times and you have an endstop repeatability measure which is not dependant on the sensor at the other end of the travel (in the case of a delta say). Sure you could do this potentially with endstops at either end of the axis, but I have never had this setup even when I had a pure cartesian machine, and I certainly don't now I have 2 delta's and a corexy.
You could then swap in a different endstop - Idris has a piezo endstop system in the works which I'd love to compare to microswitches and opticals.
Can anyone think of any easier way to do it?
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I think the best thing to do is just test it agents its self.
that's kinda what your doing on the Z probe. ( home > test distance from home > check against the average)
so, for fun you could home the printer, disconnected Z probe, connect the end stop in its place, reverse the motor. and send the same z probe commands. This would tell you how repeatable "going home" is…
you could probably do all this in software configuration with out ever moving a wire around...
just some ideas for you to chew on
~Russ
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My printer is partially dismantled to find the source of the grinding sound, and to do some work on my piezo probe setup. Once I find the time to work on it again I'll try and run your tests.
cool thanks ! I hope you find your problem!.
~Russ
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Okay sorry I will make a new thread about endstops, this isnt really the right place.
I have a DC42 IR sensor, and would be happy to (maybe this is controversial given my pushing piezo tech) run it through your test gcodes. However I would be willing to suggest having used it extensively before going to piezo, that if the bed is clean and evenly reflective it will perform very well but given a bit of ABS glue/hairspray etc it will perform far less impressively. The issue with all of this testing is its between lab testing and the real world, the lab testing for microswitches and IR sensors shows/will show amazing results but how well do they repeat this performance when printing object after object in the real world that's what I'm interested in, and thats what I am so pleased with the piezo approach, in the real world once they are setup they perform amazingly well and keep on doing so, plus they nozzle based so no offsets to be compensated for, no tilt etc….
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Here are my results with a modified design of DC42's IR probe. Pretty happy with the results. With this design I don't have to worry about my print bed, which it doesn't do well on directly (glass/PEI).
17:12:51
Bed probe heights: 0.012 0.012 0.006 0.008 0.011 0.011 0.010 0.012 0.015 0.010 0.015 0.014 0.013 0.014 0.011 0.013 0.012 0.017 0.017 0.016 0.018 0.019 0.014 0.019 0.019 0.018 0.016 0.018 0.014 0.015 0.015 0.018 0.019 0.015 0.017 0.019, mean 0.014, deviation from mean 0.003
17:16:28
Bed probe heights: 0.015 0.021 0.013 0.018 0.019 0.016 0.017 0.018 0.015 0.013 0.015 0.018 0.015 0.017 0.014 0.021 0.018 0.019 0.015 0.020 0.017 0.016 0.017 0.014 0.019 0.014 0.016 0.016 0.018 0.020 0.015 0.018 0.016 0.018 0.015 0.020, mean 0.017, deviation from mean 0.00217:30:00
Bed probe heights: 0.011 0.023 0.025 0.015 0.011 0.014 0.014 0.020 0.009 0.012 0.013 0.019 0.019 0.019 0.024 0.016 0.012 0.013 0.017 0.005 0.008 0.020 0.015 0.021 0.012, mean 0.015, deviation from mean 0.005
17:36:01
Bed probe heights: 0.013 0.020 0.012 0.010 0.017 0.024 0.010 0.014 0.012 0.013 0.018 0.012 0.006 0.024 0.019 0.008 0.011 0.012 0.008 0.012 0.013 0.018 0.015 0.012 0.015, mean 0.014, deviation from mean 0.005This is the setup: http://photos.gerbers.us/FullScreenSlideShow.aspx?gallery=4808337&mt=Photo
Don't mind all the other stuff. Currently testing out different options for the Z probe, lol
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Here are my results with a modified design of DC42's IR probe. Pretty happy with the results. With this design I don't have to worry about my print bed, which it doesn't do well on directly (glass/PEI).
This is the setup: http://photos.gerbers.us/FullScreenSlideShow.aspx?gallery=4808337&mt=Photo
Don't mind all the other stuff. Currently testing out different options for the Z probe, lol
nice work. that basically just like hall-effect but your is better, Due to the way the rod is held in place. mine is a bit sloppy. you like like you have the proper slide guides in there..
your data added to the workbook.
Higher rezhttp://open-source-energy.org/rwg42985/russ/Projects/3D%20printer/micro%20switch%20Z%20probe%20Data/Bed%20Probes%20accuracy%20others%20added.jpgwhat steps are you using? and what Duet board? yours looks like a Cartesian correct?
Thanks for Probing!!!
~Russ
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You're welcome.
I use the Duet WiFi with 16 micro steps and 256 steps interpolation. And yes it's a cartesian.
Also that slide guide is just a repurposed ball bearing. Works well enough though. -
I like that idea that's very similar to Nebbian's deployable delta probe http://www.thingiverse.com/thing:1517363 except he just uses an optical endstop so saving himself £25.
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in case you guys did not watch my other video here is what i'm using now. but i have some intresting ideas to play wth with this type of rig…
OLD VIDEO
https://www.youtube.com/watch?v=80qzmwDFGVcPS. waiting for it to go live… http://www.thingiverse.com/thing:2260909
~RUSS -
I like that idea that's very similar to Nebbian's deployable delta probe http://www.thingiverse.com/thing:1517363 except he just uses an optical endstop so saving himself £25.
The original design I based this on also used an optical endstop. But I already had the IR sensor, so I figured I may as well use it. Especially too since I can run it in analog mode.
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I also like the fact that Nebbian's probe deploys by servo but isn't positioned by the servo, and it deploys below the nozzle avoiding offsets and tilt problems.
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Here are the results from my Voron CoreXY which uses a "small white and black micro switch with the label TIAIHUA" as the nozzle-contact Z switch:
36 points moving
Bed probe heights: 0.053 0.060 0.062 0.062 0.062 0.060 0.062 0.060 0.060 0.058 0.055 0.053 0.055 0.055 0.055 0.055 0.055 0.055 0.055 0.058 0.058 0.060 0.058 0.058 0.062, mean 0.058, deviation from mean 0.003
Bed probe heights: 0.070 0.065 0.062 0.067 0.065 0.065 0.062 0.065 0.067 0.067 0.067 0.070 0.065 0.070 0.067 0.070 0.070 0.070 0.067 0.073 0.073 0.070 0.073 0.075 0.073, mean 0.068, deviation from mean 0.003
Single Point Static
Bed probe heights: 0.028 0.037 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.037 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040, mean 0.040, deviation from mean 0.002
Bed probe heights: 0.040 0.050 0.053 0.053 0.053 0.053 0.053 0.053 0.053 0.053 0.050 0.053 0.050 0.050 0.050 0.050 0.053 0.053 0.053 0.050 0.053 0.053 0.053 0.053 0.050 0.053 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050, mean 0.051, deviation from mean 0.002
Was interesting to see the results plotted:
Seems to need a few attempts before it "warms up" and becomes very repeatable.
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I hooked up my servo controlled switch for comparison to my IR setup and here are the results:
Static
21:17:00
Bed probe heights: -0.005 -0.012 -0.015 -0.015 -0.018 -0.017 -0.021 -0.022 -0.022 -0.024 -0.024 -0.024 -0.026 -0.026 -0.025 -0.026 -0.027 -0.026 -0.026 -0.027 -0.027 -0.027 -0.028 -0.027 -0.027 -0.027 -0.027 -0.026 -0.028 -0.024 -0.028 -0.026 -0.028 -0.028 -0.026 -0.028, mean -0.024, deviation from mean 0.005
21:21:50
Bed probe heights: -0.015 -0.019 -0.018 -0.021 -0.018 -0.021 -0.021 -0.022 -0.022 -0.022 -0.022 -0.022 -0.022 -0.020 -0.021 -0.019 -0.020 -0.022 -0.023 -0.020 -0.023 -0.023 -0.023 -0.023 -0.023 -0.023 -0.023 -0.023 -0.023 -0.024 -0.024 -0.023 -0.023 -0.023 -0.018 -0.023, mean -0.021, deviation from mean 0.002Moving
21:36:20
Bed probe heights: -0.054 -0.054 -0.051 -0.048 -0.038 -0.053 -0.046 -0.056 -0.058 -0.053 -0.051 -0.061 -0.059 -0.052 -0.054 -0.051 -0.053 -0.046 -0.055 -0.052 -0.059 -0.062 -0.058 -0.050 -0.053, mean -0.053, deviation from mean 0.005
21:45:09
Bed probe heights: -0.044 -0.054 -0.050 -0.041 -0.051 -0.049 -0.049 -0.045 -0.048 -0.049 -0.049 -0.048 -0.045 -0.048 -0.055 -0.047 -0.043 -0.047 -0.043 -0.043 -0.048 -0.049 -0.040 -0.038 -0.043, mean -0.047, deviation from mean 0.004This setup and switch: https://youtu.be/o2jY9fycSa0
http://photos.gerbers.us/FullScreenSlideShow.aspx?gallery=4808439&mt=Photo -
Here are the results from my Voron CoreXY which uses a "small white and black micro switch with the label TIAIHUA" as the nozzle-contact Z switch:
Seems to need a few attempts before it "warms up" and becomes very repeatable.
great results, it basically matches my other micro switches, that means your rig is quite solid and the way its build works good.
do you have some photos / information on how its set up? i would lie to see how its built.
Thanks for your results!
~Russ
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I hooked up my servo controlled switch for comparison to my IR setup and here are the results:
interesting, its a bit more sloppy. but very close. still way good i think…
i would like to see you do a contact contact test... see if you can pull off a perfect score...
Or if you have some slop in that Cartesian...here are the results of both the last 2 entry's.
any other takers... please post results.
the more data i ( we) have the better idea we have of types of probes... and printers. + errorsyour data added to the workbook.
Higher rez http://open-source-energy.org/rwg42985/russ/Projects/3D%20printer/micro%20switch%20Z%20probe%20Data/Bed%20Probes%20accuracy%20others%20added.jpgby the way if you guys look at the spreed sheet there is plots for each run like Yonkiman posted….
and it is interesting so see the plot.
i have also seen where the first probe or 2 is off but then flat lines , kinda interesting.
~Russ
[h]MORE TESTING PLEASE
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I would like to be able to contribute some data for under-bed piezo sensors but unfortunately the cost of the Duet3D prevents me from doing so at the moment. I suspect from oscilloscope and logic analyzer traces that it is at least in the 1 micron region but Arduino/Ramps/Repetier firmware only reports to 0.01mm. Of course, if anybody knows how I can coax Repetier firmware to report G30 either to 0.001mm or in raw Z stepper steps I may be able to give you the data
Mike
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if you can, just run the test any way. post the numbers. if there all flat lined then your under your liniment of the Repetier… but that's ok. because if your way out we will see that too
Thanks!!
do you have some links / photos of the bed with Piezo's?
~Russ
