Precision Piezo Z-probe Now available.

I've attached is a STEP file Piezo20.zip of the Peizo20 board to making designing with it a bit easier.

DjDemonD was gracious enough to send a board to make this possible.

Fantastic work very grateful, should be very useful.

Now added to the website [www.precisionpiezo.co.uk]

Edited 1 time(s). Last edit at 11/18/2017 08:53AM by DjDemonD.

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Simon Khoury

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

Okay so, Black Friday.. Seems fairly widespread now.

We've got 10 Self Assembly Piezo20 Modules in stock at £22.94 (15% off usual price). They will all be in transparent ABS.

When they're gone, they're gone. See my sig below for the link.

Also all the usual stuff including the ready-made Piezo20 with custom colours, The universal kit, 30mm blower fans, 50w 24v heaters, and coming soon pt100 sensors.

Edited 1 time(s). Last edit at 11/20/2017 04:44PM by DjDemonD.

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Simon Khoury

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

How does this compare to the strain gauge system devised by DC42 ?
How is the piezo disc protected from breaking in case of head crashing, hitting the bed or melted filament blobs, any obstruction ....
How do you clean the nozzle to avoid Z H error due to the residue sticking to the tip ?
Note here, what I do is to park the nozzle against a sheet of paper or PTFE when a print is completed in order to start with a clean nozzle the next print. I don't heat the extruder when homing at start to avoid dripping resulting in a blob causing Z error too. ( I mainly use PETG.)

Edited 1 time(s). Last edit at 11/23/2017 12:07PM by MKSA.

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

Hi I apologise my lack of punctuation as I am dictating this message for electronically
The system compares almost identical to the duet 3D Smart effector system in terms of accuracy and repeatability.
In terms of issues with the nozzle our advice is to flip any residual filament with a wire cutter or similar instruments before printing and then to heat the nozzle to 130° C before probing with printbed at normal first layer temperature.
This ensures that no use will occur as it is below the ooze temperature of almost all filaments.
Practically this seems to be very effective and first layers are generally highly repeatable it frequently surprises me that there seems to be a cohort of 3D printer uses who do not routinely clean the nozzle in anyway.

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Simon Khoury

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

Quote
DjDemonD
Hi I apologise my lack of punctuation as I am dictating this message for electronically
The system compares almost identical to the duet 3D Smart effector system in terms of accuracy and repeatability.
In terms of issues with the nozzle our advice is to flip any residual filament with a wire cutter or similar instruments before printing and then to heat the nozzle to 130° C before probing with printbed at normal first layer temperature.
This ensures that no use will occur as it is below the ooze temperature of almost all filaments.
Practically this seems to be very effective and first layers are generally highly repeatable it frequently surprises me that there seems to be a cohort of 3D printer uses who do not routinely clean the nozzle in anyway.

OK, then I prefer to keep doing as I do, difficult to cut the filament flush and steel against brass may damage the nozzle hole (fact is, I used to do that). PETG is really sticky, PLA was OK.
Would be nice to have in the firmware the proper sequence to heat, clean by rubbing on some kind of "brush" and park on for ex PTFE/ Silicone that resists the heat and doesn't stick (one can modify the G code too). To park on the bed without protection ends up damaging it, and thus introduce error.

What about resistance to shock of the piezo sensor ?

Edited 1 time(s). Last edit at 11/23/2017 02:19PM by MKSA.

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

Very good, you can hit them with hammers and they continue to function. They do generate large voltages when you do, but our circuit protects your 3D printer controller from those, Mike/Leadinglights has subjected some of these Murata brand piezos to 85000 x 500g impacts at 80 deg C and they still perform at a level which allows accurate probing.

In terms of other protection, the V2 universal kit pcb now operates with an active low signal by default but can operate active high for users who cannot alter their firmware which might be active high by default. If a wire break occurs between the piezo PCB and your controller it would show as triggered at the start of any probing move and no head crash would occur.

Our Piezo20 current system operates active high, so we recommend a quick upwards tap on the nozzle after powering up the machine to ensure it works. During commisioning, we recommend commanding a G30, then tap upwards on the nozzle before contact is made with the bed. If the axis doesn't stop then it needs attention. Later versions will have active low outputs by default with active high possible perhaps by a jumper or solder pad, or some other mechanism.

A wire break in the wire to the piezo is detectable but is not currently detected. If you compare to the SmartEffector which I also have, this operates active high, so will crash the bed on a fault. I am sure it wouldn't take much to change as it has a microcontroller. We are likely to go in that direction at some future point. This might also allow autocalibration or a calibration sequence that can be started for easy tuning.

As for nozzles damaging the surfaces, this is why we chose 130 deg C, is hot enough to deform residual plastic on the nozzle, but not too hot to damage a surface with momentary contact. The force required to trigger is around 5-15g, in one underbed setup I have I can blow on the bed and get a trigger, so these concerns do not practically translate into problems.

You can mount an upturned wire brush by the side of your bed and program a short gcode sequence to heat to 130 (or another temp of your choice) then clean the nozzle then probe if you want to.

We have so far no unhappy customers, some have found it a challenge to get going others have described what very accurate, repeatable, offset-free, surface independent probing can do for them as "a game changer".

Edited 3 time(s). Last edit at 11/23/2017 03:04PM by DjDemonD.

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Simon Khoury

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

Looks to me that the full up force is applied to the piezo disk center, the disk being held in place by its periphery.
Do you limit the travel to a few 1/10 to avoid forcing on the disk and breaking the ceramic ?
Can you confirm the 4 assembly screws act also as guide ? I see the two main parts are not against each other.
DC42 strain gauge system is set to trigger in the 100g range, yours in the 10g, isn't that too sensitive ?

Edited 1 time(s). Last edit at 11/24/2017 11:49AM by MKSA.

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

Yes the force is applied to the disc centre to increase the sensitivity. You can squeeze a disc across its entire surface instead, and I would recommend this for underbed setups, as the combination of 3-4 discs in parallel generates a large signal and does not need to be improved.
We don't limit the travel, the firmware raises the head when it detects a trigger, it just so happens that it is about 100microns of compliance in the disc to detect a trigger, so z offset is usually -0.1 (as it triggers "below" the bed).
The 4 screws act to preload the disc, hold the unit together and as they do not bite into the upper part allow some "slide" albeit just 0.1mm as above.
No not too sensitive at all. Lets be fair the more sensitive the better, the lower force required, the better. Since all firmware now supports nozzle contact sensors by having "pause before probing" or similar worded setting, this allows mechanical noise to settle when the head stops above a probing location, before the probing dive takes place. The only time it is a problem, in my experience is if you try to place piezos under the bed of a corexy or similar where the bed moves in Z. As the bed rises to perform the probing dive, the inertia of the bed triggers the system. I have tried quite a range of settings on the pcb and mods to the piezo bed mounts to try to solve this but haven't cracked it yet. If the bed moves in y it doesnt matter as pause before probing ceases any movement before the probing dive, and for stationary beds the result is optimal.

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Simon Khoury

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

Quote
DjDemonD
...., and for stationary beds the result is optimal.

Yes indeed.
I have two deltas - both with under bed sensors - not even mounted - just loosely put on top of the piezos (see my earlier posts).
Since I have the piezos I NEVER ever had to worry about Calibration anymore. It simply works.

Before the piezos, every evening I had to tinker arround with the bed height to get first layer perfect.

Thanks again for this really great technology!

Thank you for your feedback, do you mind if I put it on the website?

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Simon Khoury

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

Quote
Dancer

Quote
DjDemonD
...., and for stationary beds the result is optimal.

Yes indeed.
I have two deltas - both with under bed sensors - not even mounted - just loosely put on top of the piezos (see my earlier posts).
Since I have the piezos I NEVER ever had to worry about Calibration anymore. It simply works.

Before the piezos, every evening I had to tinker arround with the bed height to get first layer perfect.

Thanks again for this really great technology!

Quite frankly I don't see the interest of having a couple of piezos under the bed. One sensor (piezo, strain gauge, IR, accelerometer, simple contact ...whatever) triggered by the nozzle contacting the bed is enough.

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

Sometimes its not possible to build it into the hotend. Hotends like chimera or diamond do not lend themselves to running through a drilled piezo. We have overcome some of these difficulties by mounting the sensor in the carriage, but for some underbed is the only way they are going to be able to do it. Sure there are a number of ways to do it, but this way is cheap, easy, open source and very accurate, repeatable and convenient.

Edited 1 time(s). Last edit at 11/24/2017 06:13PM by DjDemonD.

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Simon Khoury

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

Just a quick question for UK customers.

I currently have UK orders as free shipping and therefore send them UK 2nd class.

Would you prefer to get your item quicker (1st class) and maybe pay £1.49 flat rate postage on all UK orders? I have to do it this way as I am not currently calculating shipping by individual item so the one flat rate has to even out over many different sizes/types of order.

So free but slower, or paid for and quicker? Any thoughts?

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Simon Khoury

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

I'm not that fussed, as long as delivery is consistent and reliable. If a retailer tells me 2 days but it arrives a week later that annoys me, saying that though it's a great surprise when something arrives early.

On another note, have you designed any mounts for chimera / cyclops? Piezo seems to be the way forward here with the hot swappable nozzles, no need to worry if a new nozzle is level as the nozzle is the endstop.

I'd be happy to help design a mount for chimera. I'm in the process of making a new printer and after *+#@ing around with trying to spray PEI for the IR sensor I think I want to give something better a try! Feel free to PM me, happy to lend my design skills to new mounts.

That's very kind we'd be very grateful. I have spoken to one person about chimera. Whichever is the one with two nozzles might not be helped much by piezo in that they will both have to be at the same level and you'll need a physically flat and orthogonal bed to not scrape the non working nozzle? Or am I overstating it, I haven't used one. If you talk about idex or something like that then twin z probes would make this really easy to get good results from.

The other person who is trying this is going to try a large piezo with multiple holes drilled. I'd relocate the bowden collects if they are the larger type to above the assembly and use guide tubes to minimise the amount of pzt you have to drill away. Either that or fit the piezo in the carriage.

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Simon Khoury

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

Quote
DjDemonD
That's very kind we'd be very grateful. I have spoken to one person about chimera. Whichever is the one with two nozzles might not be helped much by piezo in that they will both have to be at the same level and you'll need a physically flat and orthogonal bed to not scrape the non working nozzle? Or am I overstating it, I haven't used one. If you talk about idex or something like that then twin z probes would make this really easy to get good results from.
* I should add that I'm planning on using this for a milled flat aluminium bed, where a bed levelling feature is really only used for convenience and for the graphical bed display on a duet. My technique would be quite annoying if it was to be used regularly. My printer won't need regular levelling.

The other person who is trying this is going to try a large piezo with multiple holes drilled. I'd relocate the bowden collects if they are the larger type to above the assembly and use guide tubes to minimise the amount of pzt you have to drill away. Either that or fit the piezo in the carriage.

With the chimera (dual nozzle) I would remove one nozzle, level the first using the piezo and then add the second. shim to same height and you are done. It doesn't totally remove the need for manual input, but assuming you don't hot swap the second nozzle alot it should be fine. This method keeps wiring and complexity to a minimum, as well as keeping a nice compact carriage.

The piezo will have to live in the carriage I think, rather then on top, or of it does go on top then does it have to be centralised on the Bowdens? It could only slightly overlap the heatsink, so that the assembly is still exerting pressure on the piezo.

Either way feel free to drop me a PM. I've been commissioned to make this printer and would happily make the piezo carriage open source, or at least use the work to make a common carriage design (say mgn12, prusa or openbuilds plate)

Edited 1 time(s). Last edit at 11/25/2017 04:11PM by Origamib.

Well i tried a couple of placements on my Wanhao I3 (wedging underneath the extruder motor, between extruder motor and x carriage holder, wedging between the original hotend mount holder and a piece of pla attached with screws) but so far neither of these placements seem to give enough sensitivity to the piezo for a light tap on the nozzle to register with a sufficient signal to trigger it reliably.

Anyone else with a Wanhao I3 (or similar setup) had any luck installing these probes reliably?

You could always try underbed mounts. They work very well and with beds moving in the Y axis are not a problem for mechanical noise.

See these as an idea to get started with [www.thingiverse.com]

Edited 1 time(s). Last edit at 11/26/2017 03:23PM by DjDemonD.

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Simon Khoury

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

Well i can give it a shot. However i have a heated bed. Wouldn't that be an issue for the sensors? Also the link does not seem to work?

Thats odd working for me search thingy for "Beta Precision Piezo Bed Mounts For M3 screw fixed Beds 27mm Piezos"

Heat is fine this mount can deal with it.

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Simon Khoury

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

Quote
DjDemonD
Thank you for your feedback, do you mind if I put it on the website?

You'r welcome
And if you want you can use my pictures & OpenScad from theese two postings

I have a 27mm piezo and a V1.22 Z probe PCB mounted using a variation of the Ormerod E3D Precision piezo mount.

I am using a DuetWifi in RepRap mode.

I have adjusted the PCB so that a light tap on the hotend elicits a blue led for about 5 seconds but when I try to probe the Z the hotend just crashes into the bed

Settings are as follows

M574 X1 Y1 Z0 S0
M558 P5 X0 Y0 Z0 F420 R0.2 T6000

and the homez.g

; Lift Z relatively to current position
G91
G1 Z5 F6000

; Back to absolute positioning
G90

; Go to first bed probe point and home the Z axis
G1 X15 Y15 F6000
G30

G91
G1 Z5 F100
G90

Any suggestions gratefully received

Try reversing the piezo polarity - absolutely first thing to try. Reverse the plug and quickly retune the VR2 pot.

You can test if polarity is incorrect by pushing up (not tapping) then release. If the trigger happens on release, its the polarity.

Come back to us if that doesn't fix it.

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Simon Khoury

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

Don't I feel foolish now

That sorted it.

Thanks

Not at all I still do it myself and I still go "what the f%&K" and then reverse the polarity and carry on.

Some Piezos are not correctly polarised to match their wires.

Edited 1 time(s). Last edit at 11/27/2017 03:29PM by DjDemonD.

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Simon Khoury

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

I had began to wonder whether I had been ham fisted during the install.......

One other quick question - what Z offset do you use in your trigger height ?

I originally had it set at

G31 X0 Y0 Z0 P1000

but changed it to

G31 X0 Y0 Z-0.15 P1000

Its an E3Dv6 on a cartesian printer.

Thanks again.

Yes around -0.15 currently.

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Simon Khoury

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

Thanks, that wasn't a bad guess then.

I will post some pictures once I have tidied up the mount.

Hello All!
Total noob here with a question... I have a CoreXY printer with stationary heatbed (glass + PCB heater).
What is the better way tp place the piezo discs? Just stick them to the bottom of the heatbed or place them to the "base" and add plastic spacers on them?
Sorry for the rudimentary drawings (MSPaint)