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Precision Piezo Z-probe Now available.

Posted by DjDemonD 
Re: Precision Piezo Z-probe Now available.
March 16, 2018 12:21PM
Ahh cool yes I did see that I just didn't necessarily link your name to it. That's good I suppose diagonally opposed 2 piezo mount wouldn't work. I might change my 3+3 setup to 2+2. After doing a bit of a baseline to see how accurate its is first.

Edited 1 time(s). Last edit at 03/16/2018 12:27PM by DjDemonD.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 17, 2018 03:24AM
Simon, how did you mount your NC-piezos to the bed? [ NC= noise canceling ]
My opinion is, when you tape them to the surface with the brass side in full contact, they can't swing or bend anymore. Their signal level must be close to zero?
IMHO, you either glue them only at the center and leave the edge swinging or use 3 drops of glue at the edge.
Re: Precision Piezo Z-probe Now available.
March 17, 2018 04:29AM
I just bonded the noise cancellers on solidly with superglue. I figure since they are there to get rid of vibrations the more solidly they are in contact with the carriage I am trying "noise cancel" the better. And it does work. On this particular machine its nowhere near as accurate or sensitive as the hotend mounted piezo plate that was there before, but then its a moving-z bed, so noise cancelling or not its the least suitable use-case.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 17, 2018 03:20PM
So I was using a 3 point (2 corners and the opposite side centre) mounting system with adjustable height piezo mounts. I tried disconnecting my front centre mount piezo from the circuit but got very poor probing accuracy when I was near the front edge, there just wasn't enough movement in the system to get reliable triggers.

I also changed probe type on RRF to P8, the unfiltered mode, and it improves the range from 60 microns to 15. I am using multitouch probing, with a 30 microns tolerance it performs quite well.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 19, 2018 04:54AM
I have been looking for a new z probe for my delta. Due to a desire to play with lots of hotend styles I wanted underbed.

So I designed a bed mount, available at [www.thingiverse.com]

I haven't printed it yet but it should fit my Anycubic Kossel. Might work for other mini Kossel frames with a 220mm bed. In the description is the link for Autodesk 360 so it can be modified.
Re: Precision Piezo Z-probe Now available.
March 19, 2018 07:37AM
Looks good let us know how it works, or if you need any help tuning/tweaking it.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 19, 2018 09:53AM
Several months ago I bought a Piezo kit. I bought the groove mount because the Hot End I have is a Prometheus. After receiving the kit I tried to attach the hot end and found that although the Prometheus is a J head type hot end, it is not the same dimensions as the mount. I reverse engineered your mount design to fit the Prometheus and just recently mounted it. I redesigned my x axis carriage and went with a screw mount. It is on a Cartesian printer with a Smoothie board.
I am not using a Z axis limit switch, but using the Pieso to probe for Z and for Probing. Both of those work fine, but when in operation, I get a great many hits just from the moving hot end. I know I can reduce the sensitivity but that only turns off the LED. I am wondering if the mount has too much flex in it and maybe I should put more torque on the 4 assembly screws to make it more firm. Since I am not using it for an end stop these hits don't effect the print directly. What have others done?
Re: Precision Piezo Z-probe Now available.
March 19, 2018 02:18PM
When you say you get a "great many hits" I assume you're referring to triggers (Led flash etc) rather than the nozzle hitting the print. If that is the case then it's not normally something to worry about, Smoothieware (and all firmwares that I'm aware of) ignore probe triggers except when actually probing. The triggering itself is due to the mass of the hotend hanging off the module and vibrations in the printer. You might be able to improve things by tightening the four screws but be sure to check that the probe can still trigger before trying to probe the printbed.

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
March 19, 2018 04:29PM
Thanks, by hits I meant LED flashes. They are harmless, but it gave me the feeling that there was too much flex. I think I will print a calibration cube, and if it is good, I will just let things be. I now have excellent control over first layer height and I don't have to home to the max limit switch. That is time consuming. Great product and I am thinking of all sorts of other uses. If anybody else is setting up a Prometheus Hot End my mount files are on Thingverse.
Re: Precision Piezo Z-probe Now available.
March 19, 2018 04:35PM
Quote
keeree
[www.thingiverse.com]

I haven't printed it yet but it should fit my Anycubic Kossel. Might work for other mini Kossel frames with a 220mm bed. In the description is the link for Autodesk 360 so it can be modified.

Please do keep us posted on how this goes... I'm intending going down this route myself.
Re: Precision Piezo Z-probe Now available.
March 20, 2018 03:59PM
I'm about to order this kit. I am craz excited to try this out. There are videos that you can watch about adjusting this. My take away is that if you don't like the flashes when moving, you can experiment with adjusting the sensitivity or the tightness. This is also discussed and described in www.precisionpiezo.co's instructions as being a balancinc act between firm and not sensitive or loose and sensitive. In the end, as mentioned above, it doesn't matter if you're ignoring the signal except when probing.
Re: Precision Piezo Z-probe Now available.
March 21, 2018 02:31AM
Just to report that I managed to install and configure the piezo sensor on my Tevo Tornado. It went flawlessly, took me an hour to complete everything, including tuning. Still didn't print anything, but homing and bed leveling both working great. I will post later all the details and some photos.
Re: Precision Piezo Z-probe Now available.
March 21, 2018 02:58AM
I'd like to have a switchable 3.3V port on my DuetWifi, able to source 180mA for driving PP only when needed.
But AFAIK there are only 12 or 24V fan ports or low current signal pins...
Re: Precision Piezo Z-probe Now available.
March 21, 2018 03:00AM
How about a small mosfet switching current from the 3.3v rail on the expansion connector via one of those low current signal pins.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 21, 2018 03:22AM
Quote
o_lampe
I'd like to have a switchable 3.3V port on my DuetWifi, able to source 180mA for driving PP only when needed.
But AFAIK there are only 12 or 24V fan ports or low current signal pins...

180mA? Surely PP needs nothing like as much as that.


Delta printer calibration calculator, mini IR Z probe, and colour touch screen control panel: [escher3d.com]

Large delta printer, and other 3D printer blog postings: [miscsolutions.wordpress.com]

Disclosure: I have a financial interest in sales of the Panel Due, Mini IR height sensor, and Duet WiFi/Duet Ethernet.
Re: Precision Piezo Z-probe Now available.
March 21, 2018 04:52AM
I will remeasure the current it has been a while and quite a few board revisions since I collected that data.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 21, 2018 05:21AM
I've just measures a v2.x universal board at a maximum of 3.5ma on 5v and 1.8ma on 3.3v. Unless you put a very bright LED on the LED terminals you should be able to run it off any pin, even a low current signal pin. ( I strongly advise you to measure the current draw of your board in your setup before doing so, this has the potential to fry your controller if I'm wrong)

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
March 22, 2018 03:38AM
IIRC, the manual mentioned 180mA, but of course a separate LED would be a game changer.
If I'd go the route to use signal pins, could I use more than one pin to feed PP? The macro would look like

M42 P[x] S255
M42 P[x+1] S255
M42 P[x+2] S255
...

That way, the brief moment of switching would be the only critical moment. Would be nice if we could send M42 Pa:b:c S255 to switch them simultaniously.
Re: Precision Piezo Z-probe Now available.
March 22, 2018 04:45AM
It does mention 180ma but I don't know where that measurement comes from.

dc42 will be able to tell you for sure but looking at the datasheet for the uC on the duet it seems that most io pins are only capable of 2-4ma, you need to find one of the 4ma capable pins that's not used for some other essential function.

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
March 22, 2018 04:52AM
Please help,

How do I test the piezo probe range and standard deviation on marlin 1.1.8 (Tevo Tornado printer)?

Edited 1 time(s). Last edit at 03/22/2018 05:00AM by ValSimDim.
Re: Precision Piezo Z-probe Now available.
March 22, 2018 05:00AM
Quote
Moriquendi
It does mention 180ma but I don't know where that measurement comes from.

dc42 will be able to tell you for sure but looking at the datasheet for the uC on the duet it seems that most io pins are only capable of 2-4ma, you need to find one of the 4ma capable pins that's not used for some other essential function.

Idris

Is there some inrush/peak current?
Re: Precision Piezo Z-probe Now available.
March 22, 2018 05:24AM
Quote
o_lampe
Is there some inrush/peak current?

There shouldn't be, there are no large capacitors but I've only measured the steady current.

Quote
ValSimDim
How do I test the piezo probe range and standard deviation on marlin 1.1.8 (Tevo Tornado printer)?

Move nozzle ~2mm from the bed, run G30 20-30 times and record the readings in a spreadsheet which will allow you to calculate range and standard deviation.

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
March 22, 2018 05:26AM
The 180mA comes from a measurement I took about a year ago with a clamp meter that was probably too close to other cabling to be even vaguely correct.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 22, 2018 05:49AM
Quote
ValSimDim
Please help,

How do I test the piezo probe range and standard deviation on marlin 1.1.8 (Tevo Tornado printer)?

Most versions of marlin support M48 probe repeatability test just home move to bed centre and send M48.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 22, 2018 10:32AM
That function needs to be enabled in firm ware. In V1.1.5 in line 725,
Uncomment to enable the feature and recompile and upload.
Stef
Re: Precision Piezo Z-probe Now available.
March 22, 2018 12:08PM
I have inherited a PP V2 board that no longer adjusts properly. I placed it into my working setup and the LED blinks sporadically during probing (I'm using three piezos as "posts" under the bed). I suspect one or both of the potentiometers are worn out and noise from the frame is causing triggers. I can try to replace the pot(s). However, ordering these pots can take a while for me so maybe one of them be replaced with a resistor? If so, any suggestions on value and which pot to replace?

Another way would be to measure the working one's values and find the appropriate resistors?
Re: Precision Piezo Z-probe Now available.
March 22, 2018 12:32PM
It really depends which pot has worn out, VR1 could be replaced with a resistor, VR2 would need to be replaced with another potentiometer.

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
March 22, 2018 12:33PM
Beat me to it. LOL

So for VR1 you can use normally a 0.4Mohm resistor.For underbed setups which are usually much more sensitive, you might consider soldering a second one on top if it's too sensitive to lower the resistance.

For VR2 you need to be able to adjust it, there is no fixed value that will definitely work but something in the range of 0-100Kohm?? Idris?


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Precision Piezo Z-probe Now available.
March 22, 2018 01:12PM
For VR2 any potentiometer with a value over say 10k will work, it's a potential divider so the exact value doesn't matter.

For VR1you could try values between 200k and 1M between PZ+ and PZ- before you solder one to the board.

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
March 22, 2018 01:26PM
Quote
Moriquendi
For VR2 any potentiometer with a value over say 10k will work, it's a potential divider so the exact value doesn't matter.

For VR1you could try values between 200k and 1M between PZ+ and PZ- before you solder one to the board.

Thanks. Time for me to raid the parts drawer.
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