Welcome! Log In Create A New Profile

Advanced

Precision Piezo Z-probe Now available.

Posted by DjDemonD 
Re: Precision Piezo Z-probe Now available.
May 27, 2020 01:33PM
How do I hook um two boards on a single pin ? Is this even possible?
Re: Precision Piezo Z-probe Now available.
May 27, 2020 01:34PM
What kind of boards?

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
May 27, 2020 02:01PM
Sorry, two Precision Piezo boards to a single pin on a Ramps 1.4 (or other boards I guess). In other words: Will shorting two green wires in to a single one work? Or will everything explode?
Re: Precision Piezo Z-probe Now available.
May 28, 2020 09:06AM
With genuine Precision Piezo boards from v2.75 and up this is not a problem, just connect the two signal wires together, either board will cause a trigger.

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
May 28, 2020 01:22PM
Hi folks,

I need some assistance connecting the V2.75 PCB to my RAMPS 1.4. I have the wires coming off the PCB as Red=+, Black=Ground, and Green=Signal. When I connect the other end of the wires to the Z-min pins on RAMPS (Signal near the edge, Ground in the middle, and + near the center of the board), the LCD screen just lights up, the firmware doesn't seem to run, and the PCB gets *very* hot quickly. If I turn the RAMPS end connector around, the printer runs normally, but the PCB doesn't light up.

What am I doing wrong?

edit: nevermind, I figured it out. I wasn't looking closely enough at the pin labels on the PCB. I thought the +, Ground, and Signal lines went across the edge of the board, like the piezo pins do. I didn't notice until now that they instead run vertically. Once I reoriented the plug properly, and rearranged the wires on the other connector, it works properly now.

Edited 1 time(s). Last edit at 05/28/2020 01:46PM by AbuMaia.


MakerFarm 8" Prusa i3v
RAMPS 1.4
0.4mm E3D v6 for 1.75mm
Re: Precision Piezo Z-probe Now available.
May 31, 2020 03:11AM
Hi Moriquendi

Quote
Moriquendi

You could put the piezo in series but there are some reasons why parallel is probably better; The wiring is simpler, you don't have to run a wire from one piezo to the other, just crimp the two piezos wires together at the connector. I'm going out on a limb here but, a piezo disk is a capacitor, if my understanding is correct the piezoelectric effect is a change in the capacitance of the ceramic due to applied strain (force). Adding capacitors in parallel adds their capacitance, adding them in series reduces the capacitance. If the change in capacitance and therefore the charge flow that we read is proportional to the total capacitance then by putting the disks in series we reduce the sensitivity, while by putting them in parallel we increase it. I'm not 100% confident of my reasoning here but I think I'm right, at least in part.

Idris

Interesting assumption. Have you made any tests that confirm your hypothesis? I would be greatly interesting in the results.

I am currently trying to figure out the optimal setup for my printer. It will use 4 underbed piezos on a triple z-axis (goal is self-leveling) 330x330mm bed. Design constraints have forced me to use a sensor in each corner instead of one piezo next to each of the z-axis. As it has been confirmed numerous times that underbed piezos are too sensitive on heavy beds (and prints!) create false triggers, I currently plan to take my chances with a parallel setup or even mixed setup (2 x 2 in parallel).

Anyhow, if your findings suggest that parallel is inferior, I might change my mind.

Will report back with my results.

Edited 1 time(s). Last edit at 05/31/2020 03:14AM by sgali.
Re: Precision Piezo Z-probe Now available.
May 31, 2020 06:09AM
Although I have not tried piezo elements in series, I would think that the voltage is additive at any point in time; even if some of them are giving a negative value. As an example, say after 5 milliseconds the outputs are Piezo1 = 2V, Piezo 2 = 2V, Piezo3 = 1V and Piezo4 = -2V then the sum would be 2V + 2V + 1V - 2V = 3V. In this case, if all else is equal, and assuming the amplifier is a voltage amplifier, the 4 in series should be more sensitive.

In the case of sensors in parallel, if the voltage output from each is the same then the voltage from all the sensors is the same as just from one. If one piezo gives a different voltage then the total voltage is the average of all of the piezos - this is caused by the charge equalising between each of the piezos.

There is a difficulty in this garden of Eden however: the voltage at each sensor at any point in time depends on the pressure on it at that time. With some plate geometries, the time at which the pressure reaches each sensor can be different enough to give thoroughly unexpected results. I have seen a setup where probing of half the bed gives a trigger at 3 grams of pressure within 3 milliseconds of initial contact, the other half of the bed only triggering with 10 grams and one corner not triggering until over 80 grams of contact force.

The good news though is that having 4 piezos on the extreme corners of the bed should avoid this problem. The advisability of supporting a bed on 4 corners though is frequently the subject of holy wars on this forum.

Mike.
Re: Precision Piezo Z-probe Now available.
May 31, 2020 05:47PM
Thanks Mike for your answer. There is hardly ever an easy answer confused smiley and to make it worse, my understanding of physics is horrible.

It sounds like there is no way to tell what approach is the most reliable, both in terms of false positivies and negatives. Also, the "fiddliness" of the fine tuning process needs to be taken into account. Unfortunately, as a physics fool, I don't own an oscilloscope and even if, I would not understand it. Hence, I gotta find out the old school way by just playing around once the wiring is done.

Maybe my question boils down to that one: what does your gut-feeling tell you: what setup, series or parallel, is the most promising to start with? (I plan to use un-drilled 20mm piezos).

So I shall enter the holy war to free the path to the Garden of Eden one way or another.
Re: Precision Piezo Z-probe Now available.
May 31, 2020 07:10PM
I am having a problem where, the nozzle is not detecting the impact on the glass bed, until it has begun to exert more force than a simple impact. the result is my M851 setting has to be somewhere between 0.18 and has even had to be adjusted as high as 0.76.

I have tried a wide sweep of settings on the VR1 and VR2, the detection seems to only be so sensitive the movement of the gantry down towards the bed (this is on a CR10S) causes a detection, or, the nozzle impact must exert extra force to cause the detection.
I have attempted to "Hack" the effect by speeding up the nozzle Z speed, this way the impulse of energy from the nozzle experiencing the surface of the bed is sharper and causes a larger spike, but also seems to be somewhat less than desirable for an accurate reading. I currently have the first detection Z_PROBE_SPEED_FAST set to 1800 and the Z_PROBE_SPEED_SLOW set to 700.
If memory serves the documentation says to not exceed around 500 as a detection speed. If I set the speed below 700 the detection never fires and the z stepper keeps descending pressing the bed down even more (I'm lucky I'm still using springs on the bed otherwise it would have broken something).

Is there anyway I can modify the detection? It seems I cant make it more sensitive, because the detection is firing when the gantry begins to move, but it needs to have a steeper catch against the touch of the nozzle. So more or less, I need to change the voltage pulse of the impact, while maintaining the detection curve of the expansion card.

Am I making any sense?

I am using the larger 30mm disks, and am using this mount [www.thingiverse.com] I've printed it twice now, once in ABS, and again in PLA, both prints have the same effect (or lack of).

Any help is most appreciated!

Cheers!
Re: Precision Piezo Z-probe Now available.
June 01, 2020 04:53AM
You need to reduce the acceleration and jerk for z-probe movements. You have a lot of mass hanging off the piezo sensor so the vibration caused by starting the z-movement is causing a trigger.

You will also need to drastically reduce z-probe speed to get accurate results, I probe at 2mm/s.

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
June 01, 2020 06:57PM
OK, Hi guys, a newbie to a lot of this stuff, and a complex history behind this question.

For lots of reasons best left out of this post to save boring the hell out of the readership, a number of years ago, I got a lot of hardware to allow us to build a Delta Pi, and the project stalled and never got started.

Now, with Covid changes, and a lot more time on my hands, I'm wanting to get back into moving into 3 D printing. From reading over the time since we started, there have been a lot of changes since I got the Pi hardware, and I want to save myself some grief with getting it working so I can print usable output, but as far as I know, the basic Delta PI hardware works well when correctly set up and configured, so I don't want to waste what we got back in the day.

The original plan was a Arduino Mega, with a Ramps 1.4 and display unit, and the Hot end is an E3D-V5. The rest of it will be standard Delta Pi, and as far as I know, I have the relevant bits, like the heated bed, the glass sheet, and a Server Power supply that could double as a welder supply, if pushed, it's capable of 120 Amps, so I should be able to assemble a reasonable piece of hardware.

So, my reason for posting here in this thread,
Can I use the Piezo Z probe with the E3d V5 Hot end that I have, or am I better to get a more recent hot end to save some pain?
As the Delta Pi was originally set up for Mega / Ramps 1.4, should I continue with that hardware, or look to upgrade to a more capable 32 bit board, and if so, any recommendations given I want to use the Piezo Z probe as an upgrade?

Thanks


Shore, if twas easy, we'd all be doin it

Irish Steve
Re: Precision Piezo Z-probe Now available.
June 02, 2020 04:01AM
Quote
sgali
...
Maybe my question boils down to that one: what does your gut-feeling tell you: what setup, series or parallel, is the most promising to start with? (I plan to use un-drilled 20mm piezos).

So I shall enter the holy war to free the path to the Garden of Eden one way or another.

Neither series, nor parallel, simply put none, or one in the carriage/hotend.

Do you know any working system using 4 under bed piezo ?
DO you know any working system using 3 leadscrews plus motors to level the bed ?

Many "projects" well acclaimed but so far, no feedback, gone.

Fact is, this kind of "solution" although could be made, brings here more problems than it solves in addition to being more complex than solving the initial problem in the first place.

Edited 1 time(s). Last edit at 06/02/2020 04:04AM by MKSA.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: Precision Piezo Z-probe Now available.
June 02, 2020 06:05AM
@Irish_Steve

If you're looking to upgrade your controller board then I would suggest you get a Duet2 (either wifi or ethernet). It has lots of advantages but one of the biggest for me and the reason I will never go back to a RAMPS is that configuration is so much easier. Rather than having to upload a new firmware to update settings you just edit the config files. The duet also allows for Precision Piezo probes to work in analoge mode making tuning much easier.

If the v5 uses a standard groovemount then it will be compatible with the Precision Piezo Orion, alternatively under bed sensing is ideal for a delta printer.

@MKSA

Yes I have customers who have used 4 under bed piezos with great success.

Yes I know of many printers using 3 leadscrews to level the bed, the Railcore 2 does this.

Thousands of people are using my products with great satisfaction.

This thread is for announcements and support of Precision Piezo products. If you have questions or comments regarding PrecisionPiezo products specifically please post them, if you wish to comment on piezo sensing in general, this is not the thread to do it in.

Idris


{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.
Re: Precision Piezo Z-probe Now available.
June 02, 2020 06:05AM
I have to agree with MKSA to the extent that many interesting projects never result in feedback to the forum. In trying out new ideas the failures are as important as the successes but only if the details are also published.

As far as my gut feeling goes, I would go with parallel, but if the leads on each piezo are extended then both can be tried.

On the 4 underbed piezos, mounting a bed on 4 corners has a major problem in that it is what is called "over-constrained" where the act of mounting or adjusting can pull the bed out of flat. There is however a minor advantage in that bed can be lighter if the mountings have the right amount of compliance - although getting the compliance right is not an easy trick. If you should decide to try this 4 underbed piezos I would like to hear how it works out.

On the 3 leadscrews with motors, once again I am in MKSA's camp. Two motors for the Z axis on many Cartesian printers does work after a fashion - but is is still a kludge, 3 motors is too much of a kludge.

My attitude differs from that of many on this forum in that I think that trying out ideas to see if they solve problems is always worthwhile. To re-phrase something I have seen somewhere:

Quote
A comical prototype that works proves that an idea is possible and not so dumb - although it may still not be practical

Mike
Re: Precision Piezo Z-probe Now available.
June 02, 2020 08:42AM
@Moriquendi

He asked for an opinion, I gave it. I didn't advise NOT to use your product, but one, in the hotend/carriage. It does the job and is difficult enough.

The example you gave proved my point, too complex, problematic compared to building a proper machine, use of a simpler approach.

leadinglights made quite good prototypes, analyzed the issues extensively and published the results. Self explanatory.

Edited 1 time(s). Last edit at 06/02/2020 10:56AM by MKSA.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: Precision Piezo Z-probe Now available.
June 02, 2020 09:04AM
As an owner of one precision piezo early version, one Orion first version and one Orion last version my advice will be to use the last Orion version if possible. Just make a good mount suitable for your hotend and you will forget about leveling problems. And I strongly advise about using the Orion in analog mode, it's unbeatable. I didn't try underbed setup, but from what I read it's more complicated and hard to predict, setup and control.
Re: Precision Piezo Z-probe Now available.
June 14, 2020 07:48AM
Hi!

I am a (very happy) user of a Precision Piezo Orion kit (Module Mounting Option: Groovemount to your printer) since May 2018 (Order No. 10716 ).

I am now planning to redesign my carriage, so I'd love to understand if

  • has anyone managed to find a reliable carriage mount solution?
  • can I convert my kit to that, in case? I suppose the anser is "no" cause I have the PCB and not a bare murata sensor
  • are there some design specs of the PCB so I can attempt a design without dismantle my current setup?

For the records, I have an Hypercube corexy, with 8mm rods on the Y, E3D V6 original direct with trianglelabs "titan aero", Marlin on an ultratronics and I print on glass.
Many thanks in advance, comments & insults are welcome!


Disclaimer: io ce la metto tutta a darti consigli sensati, sta a te non incendiare nulla :-)
CoreXY HyperCube. [www.thingiverse.com] | Cerchi test? Make: test set: [www.thingiverse.com]
Re: Precision Piezo Z-probe Now available.
June 25, 2020 02:31PM
You guys wouldn't happen to have the PCB and disc Step or Solidworks files for the universal Z probe kit?
Thanks!
Re: Precision Piezo Z-probe Now available.
June 28, 2020 02:18PM
So you really not going to make any more of the 20 boards?
A little design consideration from my project:



The 20 board would have made a perfect fit on top of a 40 mm fan.
The new board is obviously to long, but it would fit with the mounting hole cut and the connector facing inwards. Then again my mounting possibilities are rather difficult.
Furthermore i would only require one piezo connection...

2 ¢
Re: Precision Piezo Z-probe Now available.
July 01, 2020 06:31AM
Okay so I'm thinking of biting the bullet. My Delta printer is now just doing nothing because indeed, as expected the Force Sense Resistor solution is not good enough.

I have two questions:
- Considering these 'corona times', are there v2.85 modules shipping at the moment?
- What is the best method of mounting? (see image)



http://www.marinusdebeer.nl/
Sorry, only registered users may post in this forum.

Click here to login