Precision Piezo Z-probe Now available.

My machine has 3 micron deviation using Marlin and M48. Results are ok always when I let all the ooze drip and especially with petg I like to thoroughly clean the nozzle before every print.
How do you get it to 130deg? Every slicer first heats the nozzle to 200+ printing temp and then runs the starting gcode to do the probing, manually editting the gcode file is just another step to forget it occured to me now that you can set the slicer at 130 and then finish heating in the starting script.

With most slicers although this refers only to slic3r/pe with any certainty, if you use a temp command in start gcode like M109 then the default heat up gcode normally inserted before the start gcode is not inserted.

I use
M104 S130 ;heat hotend don't wait
M190 [first_layer_bed_temperature] ;heat bed
G32 ; autocalibrate
M109 S[first_layer_temperature] ; heat hotend until stable

Plus a bunch of other stuff.
Those variables work in slic3r other slicers may vary.

Edited 2 time(s). Last edit at 12/06/2017 02:34PM by DjDemonD.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Sorry, I promised this video couple of weeks ago, but I wasn't able to record it until now.

[youtu.be]

As you can see, the 1.22 board is working fine, then I replace the board with the v1.21, and check the resistance (my multimeter fluctuates a lot, but it does the same with the good one, and the values is around 600 when it comes "steady"), then you can see that the led don't blink and that the VR1 is near the point where the led changes from on to off.

Any advice to have it working again?

Regards

Note I mainly print PETG and there is no way that 130°C will soften enough the plastic to allow the nozzle to clear it and reach the Z home. As to trigger below 10g, even with the nozzle at the working T° same issue plus false triggering is more likely.
I stick to my procedure. Simple and works well for me (For the Z home, I don't use auto bed leveling as it is not necessary with my heavily modified Geetech Prusa. I would with a Dela though).
Fact is, I envisioned to clear the nozzle by wiping it outside of the print area on a silicone scraper before homing and found it unnecessary. If required, I just remove the excess melted filament sticking to the sides of the nozzles.

---

"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

Quote
okercho
Sorry, I promised this video couple of weeks ago, but I wasn't able to record it until now.

[youtu.be]

As you can see, the 1.22 board is working fine, then I replace the board with the v1.21, and check the resistance (my multimeter fluctuates a lot, but it does the same with the good one, and the values is around 600 when it comes "steady"), then you can see that the led don't blink and that the VR1 is near the point where the led changes from on to off.

Any advice to have it working again?

Regards

Having watched the video it might be a failed board. I have sent a PM.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Quote
okercho
Sorry, I promised this video couple of weeks ago, but I wasn't able to record it until now.

[youtu.be]

Thanks for that video. That is what I am now seeing too and reported a few days ago - but I only have the one board :-(

[forums.reprap.org]

Quote
lord_alan

Quote
okercho
Sorry, I promised this video couple of weeks ago, but I wasn't able to record it until now.

[youtu.be]

Thanks for that video. That is what I am now seeing too and reported a few days ago - but I only have the one board :-(

[forums.reprap.org]

Pm sent.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

You should do a post mortem on these boards. The protection may not be sufficient. Piezo can produce very high voltage spike.

---

"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

I will be doing a thorough analysis into why these boards are not working as they should.

Idris

---

{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

Quote
MKSA
You should do a post mortem on these boards. The protection may not be sufficient. Piezo can produce very high voltage spike.

We are very aware of that, and so far have had a very low failure rate something in the order of 3 boards out of 300, which given that the design has been constantly evolving and they are presently handmade, is lower than I would have expected.

I have one of the first V2 universal kit boards on my microdelta printer, and it has been constantly powered up, and in use for 3-4 months now, with no sign of any issues.

One of the great advantages of using a PCB like ours is the protection it offers your 3d printer controller, an (often) more expensive component since some advocate the use of piezos wired directly to endstop channels.

Edited 1 time(s). Last edit at 12/07/2017 07:05AM by DjDemonD.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Quote
DjDemonD

Quote
MKSA
You should do a post mortem on these boards. The protection may not be sufficient. Piezo can produce very high voltage spike.

We are very aware of that, and so far have had a very low failure rate something in the order of 3 boards out of 300, which given that the design has been constantly evolving and they are presently handmade, is lower than I would have expected.

I have one of the first V2 universal kit boards on my microdelta printer, and it has been constantly powered up, and in use for 3-4 months now, with no sign of any issues.

One of the great advantages of using a PCB like ours is the protection it offers your 3d printer controller, an (often) more expensive component since some advocate the use of piezos wired directly to endstop channels.

Electronics tend to die at power on/off and various other transient events. Here a kick in these piezo can generate spikes in the 100V range.

---

"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

Thanks for the info. However it is worth pointing out that there has been some substantial research done by Mike, Idris and myself posted here [forums.reprap.org] Mike and I have submitted an article on piezo electric sensing for 3D printing to a peer reviewed journal. However if there is any further information, beyond the basics, we're happy to hear it.

Edited 1 time(s). Last edit at 12/07/2017 09:28AM by DjDemonD.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Quote
DjDemonD
With most slicers although this refers only to slic3r/pe with any certainty, if you use a temp command in start gcode like M109 then the default heat up gcode normally inserted before the start gcode is not inserted.

I use
M104 S130 ;heat hotend don't wait
M190 [first_layer_bed_temperature] ;heat bed
G32 ; autocalibrate
M109 S[first_layer_temperature] ; heat hotend until stable

Plus a bunch of other stuff.
Those variables work in slic3r other slicers may vary.

FYI, if you don't want to use M104 because it is deprecated in RRF, putting it inside a comment will keep S3D from inserting it automatically, too!

Apologies for the noise - I did some more tests this morning and could get the led to flash under pressure changes on the disc so the board seems to be working correctly. FWIW I found I had to be _extremely_ careful turning back VR2 so the LED went out. Maybe I had turned it back too far on my previous tests...

Glad its working, check vr1 resistance 0.4mohm is usually enough but go higher for more sensitive and vice versa.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

ohm is for resistance, mho for conductance but mohm ?????

---

"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

Mega-Ohms.

I am truly sorry, I should have written it MOhm's right?

Anything else?

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Quote
DjDemonD
Mega-Ohms.

I am truly sorry, I should have written it MOhm's right?

Anything else?

I was just kidding !

Indeed m for milli, M for Mega. therefore you should have written 400 kΩ

Edited 1 time(s). Last edit at 12/10/2017 08:07AM by MKSA.

---

"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

Okay fair enough, apology accepted.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Finally got my Piezo20 kit working today. Took a while to work out that the piezo polarisation was reversed. I had to invert the 2-pin connector so the black wire was closest to the pcb edge.
At the moment I've only tested the homing & levelling. Next job is to try a print.

One improvement I could suggest is using a multi-turn pot for VR2. I might fit one to my pcb to make adjustment easier.

Printer: D-Bot with Ramps 1.4 & Marlin (1.1.5).

Glad its working ill make sure to check the instructions about polarity but if it any consolation I do it all the time and I've made hundreds now. Occasionally a piezo is the wrong polarity inherently.

I'm sure Idris will chime I'm on the potentiometer.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

There are two reasons I've not gone for a multiturn pot. The first reason is cost, a multiturn pot is 10x the cost of a single turn pot even in quantity. The second is that with a multiturn pot I've found that it's quite easy to get lost and not know where in the range you are.

There are some other options that would widen the tuning window that I'm exploring at the moment that may be implemented in future revisions.

Idris

---

{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

Looking forward to seeing this product develop in the future

Warning: Do not attempt the following unless you have very steady hands

I soldered a 100k multiturn pot in place of VR2 this morning. Adjustment is much easier now. The pot is stuck to the pcb with double-sided tape. It seems pretty stable but I may order a spare just in case it fails in the future. Apologies to the PP guys for hacking your product about




Homing on Youtube

Edited 2 time(s). Last edit at 12/11/2017 06:34AM by tekkydave.

No worries at all, you bought it and its yours to hack, we love to hear how it can be improved.

Where we are eventually going with this is a microcontroller version, which will either be initially setup via USB, in the same way you might program an arduino, or eventually a self-calibrating unit with a calibrate button, press it , do a few probes by hand, then a few onto your bed, and it sets itself up.

But for now that looks like a worthy mod. If you found the trigger point on VR2 a little fiddly to set, personally I don't but then familiarity is not to be taken for granted.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I was more worried about the longevity of the pot given that I'm an eternal 'fiddler'

Well we have had some issues with these things used for very active development the pots can wear out. However if you tune it and then just use it they last very well. Perhaps there would be a space in the kit version which is often used more experimentally than the piezo20 pcb, for a "dev" version with more substantial potentiometers, which would be a little more expensive.

Edited 1 time(s). Last edit at 12/11/2017 07:37AM by DjDemonD.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Results of M48 repeatability test:

SENDING:M48 P5 X150 Y140 V4
M48 Z-Probe Repeatability Test
Positioning the probe...
Bed X: 150.000 Y: 140.000 Z: 0.031
1 of 5: z: 0.002 mean: 0.0019 sigma: 0.000000 min: 0.002 max: 0.002 range: 0.000
2 of 5: z: 0.007 mean: 0.0044 sigma: 0.002500 min: 0.002 max: 0.007 range: 0.005
3 of 5: z: 0.004 mean: 0.0044 sigma: 0.002041 min: 0.002 max: 0.007 range: 0.005
4 of 5: z: -0.005 mean: 0.0020 sigma: 0.004428 min: -0.005 max: 0.007 range: 0.012
5 of 5: z: 0.008 mean: 0.0031 sigma: 0.004524 min: -0.005 max: 0.008 range: 0.013
Finished!
Mean: 0.003125 Min: -0.005 Max: 0.008 Range: 0.013
Standard Deviation: 0.004524

That looks to be performing spot on. Good results. 13 microns accuracy - should do the trick.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

14:27:08.243 : M48 Z-Probe Repeatability Test
14:27:08.243 : Positioning the probe...
14:27:11.446 : Bed X: 200.000 Y: 120.000 Z: 0.255
14:27:13.727 : 1 of 5: z: 0.286 mean: 0.2862 sigma: 0.000000 min: 0.286 max: 0.286 range: 0.000
14:27:16.009 : 2 of 5: z: 0.281 mean: 0.2838 sigma: 0.002500 min: 0.281 max: 0.286 range: 0.005
14:27:18.274 : 3 of 5: z: 0.283 mean: 0.2835 sigma: 0.002062 min: 0.281 max: 0.286 range: 0.005
14:27:20.556 : 4 of 5: z: 0.279 mean: 0.2825 sigma: 0.002539 min: 0.279 max: 0.286 range: 0.007
14:27:22.821 : 5 of 5: z: 0.279 mean: 0.2819 sigma: 0.002592 min: 0.279 max: 0.286 range: 0.007
14:27:23.821 : Finished!
14:27:23.821 : Mean: 0.281875 Min: 0.279 Max: 0.286 Range: 0.007
14:27:23.821 : Standard Deviation: 0.002592
14:27:23.821 : X:200.00 Y:120.00 Z:10.11 E:0.00 Count X:16000 Y:9600 Z:16176


These are the results with V2 on my Tevo Black Widow. Bed is 40cm x 12cm y. A single 27mm piezo mounted under bed carriage center . will try the 41mm piezo (active area is 25 mm) For the 27 mm- the active area is 20mm.

Stef

Edited 2 time(s). Last edit at 12/12/2017 02:50PM by Chowa.