Precision Piezo Z-probe Now available.

Hi there is a scheme being proposed to stick them to the underside of the bed, by a website supplying "similar" products to ours. It might work, if the bed is cold, and if the tuning is very precise so they work like microphones rather than force sensors. However mounting in some kind of mounts works best.

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Simon Khoury

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

Option 2 (piezo stuck directly to bed) is unlikely to work well for you. The output of the piezo disk falls as temperature increases reducing sensitivity. Furthermore, although piezos can detect vibration in the bed it is much more effective to squeeze or bend the disks, go with option 1.

Idris

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

@mokush

Your first option will work but will stop the bed leveling from working. You could look at a couple of the methods in this post. [forums.reprap.org] The parallel mechanism in the second picture is the one that I use but it is overly complex and the main reason I stay with it is that I can quickly change piezos. The method shown in the last diagram needs three drilled piezos but no parallel mechanism. There are some STLs and other info in [www.thingiverse.com] and [www.thingiverse.com]

Mike

I made a universal mount for the PZ20 board for use with pretty much all Prusa i3 and clones. Initial testing looks good so far.

[www.thingiverse.com]

That's looks great and superb write up in the description. Can't wait to see the multifunction pcb in action.

Edited 1 time(s). Last edit at 11/29/2017 03:14AM by DjDemonD.

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Simon Khoury

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

Thank you for all the answers.
In the post, mentioned above, there is a design:


What is pretty similar to mine. But this also makes bed leveling hard, no?
May I use a bit flexible spacer (rubber or so)? Can these materials provide enough pressure for the discs?

Have you seen my design much simpler and you can adjust it with a screw?

[www.thingiverse.com]

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Simon Khoury

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

Sorry, I can only find "404" on tis link. What is the name of that thingie?

Weird all of my thingiverse links dont work at the moment.

Try searching thingiverse for

Beta Precision Piezo Bed Mounts For M3 screw fixed Beds 27mm Piezos

Simon.

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Simon Khoury

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

Hello Simon,
no luck at all. I only find the one that was designed for delta printers (thing:2446460)

Edited 1 time(s). Last edit at 11/29/2017 06:11PM by mokush.

27mm_under_bed_mounts_for_m3_screw-bed_thumbwheel.stl

"These are bed mounts for the Precision Piezo, z-probe system.

There are 3 parts. The lower part, cup shaped has a screw mounting hole to attach to your carriage. Attach it with an m3 screw. Then insert a 27mm piezo with cermic facing upwards.
Thread the leads through the small hole. This works best with Murata piezos with skinny leads.

Now take the middle part (disc with hole in it), and upper part (thumbwheel), and file a little of the hole away in the middle part so the upper part fits in snugly but can still rotate. Separate them. Bond the middle part to the lower part around its circumference (superglue/acetone) so that the flat side faces up.

Now make the hole in the upper part that goes down through the plunger 2.8mm by drilling it out. Dont drill all the way through the plunger leave around 1mm of plastic there.

Fix the bed with me screws, use a washer on the underside then a locking nut. Do it up tight. Then screw this into the thumbwheel/upper part plunger. around 2.5mm.

Now repeat on either the other 3 (or 2) mountings. Now you can fit the bed to the lower/middle part piezo holders using the plungers.

To adjust bed level, you will have around 2.5mm up or down travel, use a screwdriver/hex driver to hold the screw going through the bed from above. Then turn the thumbwheel to raise/lower the bed.

Wire the piezos to a Precision Piezo (www.precisionpiezo.com/shop) PCB (or see site for details on how to make your own), and follow Piezo kit guide there to tune the circuit."

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Simon Khoury

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

Do you have a US seller of the product?

No.

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Simon Khoury

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

We don't have a reseller in the US but we do ship worldwide.

Idris

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

Thank you!

Show us your first layer...

Thats what this is all about right?

I'll kick off [www.facebook.com]

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Simon Khoury

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

I haven't seen much that talks about using a e3d cyclops and detecting movement at the hotend holder instead of bed mounts. Any tips on this? Basically mounting the e3d flat against a aluminum carriage

I have spoken to a few people who are in the process of designing something to make chimera/cyclops hotends work with piezo, I haven't got one myself so I am reliant upon a community effort to some extent.

As this grows we can steadily acquire some hardware for testing purposes, for example, I recently ordered a CR-10 since they are so popular at the moment, to see if I can come up with a way of mounting piezo to that machine.

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Simon Khoury

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

Newbie/Dumb question coming up ;-)

I bought a Universal board recently and as I have an account with RS I bought some Murata discs from them (20mm).

Using a simple 3.3.v LDO power supply (I use when messing about with ESP8266 chips) I stuck a couple of dupont connectors on one of the discs and got the led to flash on and off on the board by applying virtually no pressure on the disc - :-)

However, now after doing a few tests like that whilst I was thinking about the best design for my Anet A8 printer, it doesn't seem to work any more. I _can_ get the LED to go on and off by adjusting VR2 as described in the manual (yes I did read it) but I don't get any indication/reaction when applying pressure to the disc. (I have tried two discs now),

Are there any further diagnostics I can do before deciding I've blown up my universal board? (I did try connecting either disc to any of the three input pairs).

TIA

Al

It's very unlikely that you've blown up the board, they're pretty well protected. Are you following the correct tuning instructions? tuning is different for v1.22 boards (no mounting holes) and v2.02 boards (with mounting holes).

Other things to check,

Solder joint from wires to piezo, the solder joint to the silver part of the piezo is particularly delicate.
Crimp connections
Polarity of the piezo, try plugging it in the other way.

Idris

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

for all of you duet users who wonder which probe offset to put in your FW:

the method described here:

[duet3d.com]

gave me -0.13 and it is dead on everytime!

Yes definitely use G31 with duet remember with piezo the probe triggers effectively below the bed unlike inductive, ir etc.. , so use a negative number. Mine is usually between -0.1 and -0.15. If you babystep and have to go up one babystep (0.05mm) then you need to invert this and add it to your G31 offset. So if I begin with G31 z-0.1 and find I am too low by one babystep - that is I go up 0.05mm then I change use G31 -0.15 instead.

For a while I was adding the offset and always wondering why I was one babystep too high!

Edited 2 time(s). Last edit at 12/05/2017 09:40AM by DjDemonD.

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Simon Khoury

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

Thanks. Yes I am using the manual for the v1 board. I'll check everything carefully.

The ugliest part about this piezo being so accurate is ooze... I must heat and wait letting it all drain out, then clean the nozzle with a wire brush.
If I go on with probing without a good 2-3 minutes of draining, sometimes just before it touches the plate I get a little ooze and there goes 0.1mm of my precision...
Long live Marlin with it's great double click to babystep, and shame on Smoothie for intentionally not having this feature.
I've tried using temps from 130 to 180 degrees just to let the plastic to soften and get no ooze, still +/- 0.1mm of error depending on how much ooze I got on the nozzle.
The only other approach to waiting would be to use something like 160-170 degrees and lower the piezo sensitivity to make it press harder, but I like the feather touch, so back to waiting for all the ooze to drain.

Odd that you struggle with it. I just use 130 and clip with wire cutters then walk away from the printer and come back when my object is ready.

What hotend are you using? And material?

You could begin a probing sequence by heating to 130 then pausing to clip filament, then do G30 at side of the bed or bed centre to squash down any residual material then autolevelling or calibrate. I don't see 100 microns error if I did my delta wouldn't calibrate to 3 microns deviation and my corexy bed maps would look like the hymalayas.

Edited 1 time(s). Last edit at 12/06/2017 07:10AM by DjDemonD.

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Simon Khoury

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

Would you be willing to try using direct electrical contact to see how much is printer related and how much is sensor/ooze?

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Simon Khoury

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

I always remove any old ooze from the cold nozzle before starting the print.
First probe with cold nozzle, then heat up.

Only thing I had to do was correct trigger height by I think 0.07mm for heat-expansion

Although I don't use a piezo, here is how I proceed: [www.thingiverse.com]

I don't like the idea of touching the nozzle with any kind of cutter/scrapper specially with PETG that ends up covering totally the nozzle.

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

Interesting idea.

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Simon Khoury

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

A couple of thoughts about the problem of the ooze getting in the way. First I must stress that I haven't done any practical experiments to check this - maybe I will put it onto the list of things to try.
The plastic is squashed between the flat face of the nozzle and the build stage and any that is pushed off sideways will come up against the slope of the side of the nozzle. Having the smallest possible flat face and a steep angle to the adjacent sides of the nozzle should push through the plastic much easier. I have tended to make my nozzles so that the diameter of the flat face is twice the nozzle hole diameter - e.g., a 0.3mm nozzle will have about a 0.6mm diameter face. My sides have been at 45° to the face and could easily be sharpened up to 60°.
The first devils-advocate thought is that the nozzle would be more likely to damage the build surface but I think we may be able to achieve reliable probing at somewhere in the region of 1 to 5 grams of contact pressure.
The other part of the equation could be to have a completely reliable method or mechanism for cleaning the nozzle immediately before probing.

Mike