Piezo benders / Actuators

[ClydeCrashKop]

I have had an idea for an array of extremely small pneumatic valves for a long time now.
Every time I look, piezo benders seem to be cost prohibitive.
If I need 8 per valve and the benders cost more than I can charge for the valve, I forget about it for a while again.
I can't understand this with piezo alarms and speakers being so cheap and toys and greeting cards have piezo speakers in them and cost very little.
Long ago I heard that you can buy broken sheets or scraps for next to nothing.
Can I make a bender by cutting a speaker into strips?
Am I missing something?
Where can I buy a few small benders that will move 0.007" or more?

 

[Norator]

There are other materials that convert current into force.

 

[ronv]

Maybe something like this would work for a prototype?

**broken link removed**

 

[Vizier87]

I have had an idea for an array of extremely small pneumatic valves for a long time now.
Every time I look, piezo benders seem to be cost prohibitive.
If I need 8 per valve and the benders cost more than I can charge for the valve, I forget about it for a while again.

Long ago I heard that you can buy broken sheets or scraps for next to nothing.
Can I make a bender by cutting a speaker into strips?
Am I missing something?
Where can I buy a few small benders that will move 0.007" or more?

Hi,

I can't understand this with piezo alarms and speakers being so cheap and toys and greeting cards have piezo speakers in them and cost very little.

Probably it's because the ones in alarm clocks act only as buzzers. You'd need high voltages to drive them, up to 200V.

There are piezo actuators like this one:
https://www.youtube.com/watch?v=waZzr8WyXJA

However I contacted them Cedrat guys for a quotation and they returned zilch. So I Gurggled around and found the Noliac actuators. I bought a few and stacking 'em together is pretty easy, just follow the graphics in the datasheet. The driving part is, however, the main issue. IF you plan on buying the driver, it'll cost like a few hundred euros. I think mine is €600. Otherwise, I have just planned on driving it on my own using piezo drivers like this one (and you can order free samples), but it's QFN-based so it's pretty hard to solder.

I just got up to the research part and I haven't carried out the prototyping, but this'll save you a lot of time. If you're up to it then please continue updating your progress, I am really interested if this works out for you. On my end, I managed to perform the actuating part but using a Signal Generator with the driver, and it's really bulky.

Cheers.

 

[ClydeCrashKop]

Thanks guys
That fan looks interesting. I think that fan is made by this company.
**broken link removed**
Good info **broken link removed**
The patent for it https://www.google.com/patents/US5861703

I found this Clearance Stripe Actuators Mix & Match 20pcs/$100
https://www.americanpiezo.com/index.php/?option=com_content&view=article&id=125
They said disregard the minimum order of 10 units.


I will learn a lot from that TI data sheet.
I have a reflow station and solder paste but haven't tried it yet.

I found this How to make Rochelle salt piezoelectric crystals
https://www.youtube.com/watch?annot...&feature=iv&src_vid=R7zjfaPKMSE&v=E1Ct3VUWvhQ
There are many more. I shouldn't forget Youtube in my searches.

 

[Vizier87]

Well Youtube does give a fairly graphical idea. It's important if you want to extend your imaginations. All the best.

 

[ClydeCrashKop]

That fan looks like piezoelectric film. Pretty interesting stuff but won't exert much pressure.
**broken link removed**
Fun With Piezoelectric Film
https://www.imagesco.com/articles/piezo/piezo00.html
Bimorphs: Motion can be created using piezoelectric film. To do so, two sheets of film are joined together. This assembly is called a bimorph. The sheets are arranged so that when a voltage is applied to the bimorph, one film laminate lengthens while the other contracts. This caused the bimorph to bend. Applying voltage of the opposite polarity will cause the bimorph to bend in the other direction. An AC voltage will cause the bimorph to fan like an insect wing. At resonance, maximum movement will be obtained from the bimorph. Resonance is determined by the length and thickness of the piezo materials used in the construction of the bimorph.

The benders that I found on sale only exert 1/4 oz. of pressure. I need about 7 oz. pressure to close off a tiny air hole. So I haven't made much progress.

 

[ronv]

Here is some interesting "stuff". Maybe it could work for your application.

http://robotics.hobbizine.com/flexinol.html