adhesive dispensing shaped nozzle

[asimpson]

I wish to dispense an adhesive or sealant in a continuous circular pattern about 10 mm onto a flat metal foil disk. Epoxy or acrylic UV cured are favoured.

This will be used in automation machine working at 60 shots per min.

Rather than a single point nozzle and moving in circular pattern, are there any nozzles available, capable of generating continuous circular pattern in one shot?

I will be using a precision metering valve lipe an EFD Pico.

thanks

 

[racookpe1978]

1 sec interval BETWEEN shots means the whole shot sequence needs to be:
- have the material stop relative motion (between injector and substance)
- have valve turn on
- have fluid flow between valve and needle tip
- have fluid leave needle tip and hit substance
- have fluid hit substance and (start) spreading out in a "a very even" round pile
- have valve shut off
- have fluid stop all the way between valve and the "pile" on the substance (no drips!) and no spatter and still have the "pile" be even and round (or it won't spread out into an even round final shape)
- have the substance accelerate again (either needle move or substance move)
- reposition the two (needle and substance)

Ain't gonna happen easily. All of above assumes the "glue" will smoothly spread out again into your theoretical perfect circle after deposition.

This is why most dispensers like that use a continuous circular path of many hundred needles simultaneously injecting a stream of material into the rotating "bottle mouth"
of the empty containers going past. No relative motion and no acceleration problems between needle and bottle. Each needle valve can open-operate-close with the fluid getting injected into the bottle (in your case, on to a single even point or "pile" of liquid) while other "piles" are in other parts of the assembly line.

Very, very expensive to set up and test. Very cheap to operate once running.

Costs much more though.

 

[MadMango]

The shape you are referring to would be some sort of hollow core extrusion tip. I think with adhesives, that would be trouble.

You could also try transferring the adhesive from a "well". The well would have a wiper that would keep the thickness constant, then a pad could dip into the well and transfer a ring of adhesive to the foil (think rubber stamping). You would have to hold the foil in place so it didn't stick the the pad. Given your process time requirement, this could be achieved with a delta robot (3 parallel arms).

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[dgallup]

I've made spray nozzles that create a circular hollow cone spray pattern. They used a swirl generator like on the end of a garden sprayer. You can certainly have a valve that opens and closes in far less than one second, typical electromagnetic fuel injector valve opens in ~1.5 ms and closes in 0.5 ms, can stay open as long as you like. The big question to me is what is the viscosity and surface tension of this adhesive or sealant? Might be very hard to get it to spray cleanly. Also, these swirl generators take a little while for the spray pattern to start up. For the first fraction of a ms they spit out some droplets in the center then open up into an "onion" then form the hollow cone as the fluid velocity and rotation stabilize.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[btrueblood]

"Rather than a single point nozzle and moving in circular pattern, are there any nozzles available, capable of generating continuous circular pattern in one shot?"

It sounds like you want to make a donut, or toroidal form? Look at the nozzle of a donut making machine.

...He said, expecting to be able to pull up a link on google images....

If you don't know what one looks like, I could sketch it...

 

[mcgyvr]

nordson has some products with a "spiral/swirl spray pattern?

http://www.nordson.com/en-us/divisi...s/Dispense-Valves/Pages/Swirl-Applicator.aspx