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A DIY Vacuum Pick & Place Tool

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A DIY Vacuum Pick & Place Tool

Postby Jon Chandler » Tue Aug 20, 2013 3:44 am

As you've seen from my recent posts, I acquired a solder paste dispenser on the cheap and have a low-cost hot-air system from eBay. That left only the problem of getting SMT parts on to the paste-covered PCB. Tweezers are a common way to do this, but I always manage to nudge the parts out of position when I let go of the tweezers.

A vacuum pick & place system seemed like the most efficient way to get parts placed on a board. Vacuum is drawn through a blunt large gauge hypodermic needle to pick up a part and the vacuum released when the component is in place. The quick&dirty method uses a hole in the hand piece to control the vacuum. Seal it with a fingertip to pick up a part, and move the finger to release the vacuum when the part is in position. This part isn't too challenging.

So how do you create a vacuum? The solder paste dispenser has vacuum "suck back" created by running compressed air through a vortex. This method uses a lot of air to create a little vacuum, but since you need compressed air anyway, it works pretty well. I found one of these vacuum generators on eBay for about $12 and was considering building a pick & place system around one of them.

Then I had the thought...nebulizers used for inhaling medications for asthma create a low-pressure, low volume air stream using some kind of pump, and can often be found at thrift stores around here for a few bucks. Hmmmm....there might be some potential there to convert a nebulizer to a vacuum pump. I did a Google search to see if anybody has tried this. I didn't find anything about anybody trying this. What I did find was more interesting! There were a number of listing for nebulizer/vacuum pumps – a diaphram pump is used in nebulizers to create an air flow, but these same pumps can also be used as a vacuum pump!

I was in luck and found a nebulizer at the thrift store today – it had actually been there a while and was still there today. For $6 it was mine. The nebulizer has an outlet fitting for 1/8" or so tubing to the "business end" and a little filter on the suction side – you obviously want the air flowing into somebody's lungs to be clean. The easy way to use this little vacuum pump is to connect the hose to your pickup to the filter inlet. The one I got actually had a little nub to slip a hose over when the filter was removed.

The better way to do it is to open the case and switch the hoses around. Yes, this is truly a 5 minute project! The former air outlet is now the vacuum connection and the filter becomes the air outlet; this works well as the filter acts as a muffler for the discharge air.

Screw the case back together and you're in business.

Nebulizer on Amazon

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Re: A DIY Vacuum Pick & Place Tool

Postby Jon Chandler » Tue Aug 20, 2013 4:12 am

My hand piece is pretty simple. I started with a cheap BIC pen - the kind with the clear tube with a small hole in the side. Remove the ink part of the pen and the end cap, leaving just the barrel. The small-diameter tubing I had was a tight fit in the point end of the tube, so I pushed enough in to make a good seal.

The needle I used was part of the solder paste dispenser accessory kit I bought from eBay. I selected the largest diameter for this task. I put a piece of wire inside the needle and curved it a little to make a better working angle. The plastic part of the needle is just about the same diameter of the top end of the BIC barrel. I attached it in place with a length of adhesive-filled heat shrink.

The existing hole in the BIC barrel is a bit on the small side – there's still some suction from the needle when the hole is uncovered. A small drill will remedy that.

The suction of the system is enough to pick up a US nickel (5 cent coin) with careful placement; a nickel conveniently weighs 5 grams. This should work well to pick up most any component.

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Re: A DIY Vacuum Pick & Place Tool

Postby Jon Chandler » Tue Aug 20, 2013 10:12 am

One thing I may want to add is some kind of inline air filter to prevent anything from being sucked into the air pump. The needle bore is small but bits of cut wires or a shot of solder paste if a pad is inadvertently touched could doom the pump.

I have a few ideas rolling around in my head for a solution. More on this when I have a good answer.
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Re: A DIY Vacuum Pick & Place Tool

Postby Jon Chandler » Tue Aug 20, 2013 10:41 am

With a little searching, I came across fuel filters for r/c (radio controlled) planes or cars. These filters are fairly fine, so could work well for this application. I'll put something like this in- line.

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Re: A DIY Vacuum Pick & Place Tool

Postby Jon Chandler » Tue Aug 20, 2013 5:46 pm

Well, despite the truly underwhelming response, I will provide some details of the completed system. It seems like it will work very well for a cost of less than $15.

Here's a photo of the completed system. I like this nebulizer as it looks business-like and at home on the bench. The only change to the nebulizer was internally swapping the hoses at the inlet and outlet ports. Connected by a short length of hose is a home-brew filter to prevent the air pump from sucking in any crap. The other end of the filter connects to the handpiece with about two meters of plastic tubing.

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The inline filter is made from a syringe (from the local farm store) and aquarium air stone. I pulled the plunger handle from the black rubber plunger, punched a small hole and pushed the neck of the air stone through. The plunger sealed without the need for any glue. It may not show up in the picture but there are a couple pieces of clear plastic cut from a package inside the syringe to stop the plunger from sucking all the way into the syringe. The amount of vacuum produced easily sucks the plunger all the way in.

The gap between the inlet fitting and air stone is intention so that any crap sucked in can fall out of the stream. The suction side should be connected to the air stone to allow this to happen.

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Finally, here's another picture of the handpiece. The body is the barrel from a BIC pen. The normal hole in the barrel, combined with a finger, is the vacuum switch – cover the hole to pick up a part, uncover to release. It needs to be drilled out slightly to completely dump the vacuum. The tip is a slightly curved large-bore hypodermic needle with a blunt (squared off) tip. I got this as part of a kit of solder paste accessories. If you can't get a blunt-tipped needle, grind off a regular one square. The needle is held to the barrel with a piece of adhesive-lined heat shrink tubing.

Note the position of the hole in the barrel vs. the tip – I'm left handed, so this works for me. Consider the position before heat-shrinking the needle on.

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Re: A DIY Vacuum Pick & Place Tool

Postby Baldor » Wed Aug 21, 2013 2:25 am

Hey, the lack of response could be because we don't have anything to add. At least this is my case.

Maybe the filter could be a simple piece of foam? And also, the first nebulizer you show, is surprizingly similar to an acuarium air pump. Seems almost any diaphramg air pump could be converted.

Be sure, I will reread the entire post when I start working with SMT parts.
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Re: A DIY Vacuum Pick & Place Tool

Postby Baldor » Fri Aug 23, 2013 2:02 pm

http://www.ebay.com/itm/DC-12V-30Kpa-DC ... 4610629b73

http://www.ebay.com/itm/DC-12V-50Kpa-DC ... 4d10f222bf

Seems this pumps could do the work. But it needs power suply and an enclosure.
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Re: A DIY Vacuum Pick & Place Tool

Postby Jon Chandler » Sat Aug 24, 2013 7:13 am

Baldor wrote:
http://www.ebay.com/itm/DC-12V-30Kpa-DC ... 4610629b73

http://www.ebay.com/itm/DC-12V-50Kpa-DC ... 4d10f222bf

Seems this pumps could do the work. But it needs power suply and an enclosure.


Those pumps look like they'd be great.

People have converted aquarium air pumps, which can be as simple as swapping inlet and outlet valves or more complicated requiring making an airtight connection where none was ever intended.

Some inkjet printers had a peristaltic pump to suck ink from the print heads for cleaning...but not all of them do (the one I ripped apart for that reason did not) that may work well too.
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Re: A DIY Vacuum Pick & Place Tool

Postby Baldor » Sat Aug 24, 2013 7:32 am

Some day I must open the acuarium pump I'm using for my etching tank. (10€ at the pet store) But I think the conversion will be dificult, from the outside I can´t see an air intake.
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Re: A DIY Vacuum Pick & Place Tool

Postby Jon Chandler » Sun Aug 25, 2013 3:15 pm

I took apart an old automatic blood pressure meter to see what treasures in might contain. It has a small (2.5" x 1.25" diameter) air pump, but it's not amenable to modification to a vacuum pump.

But I did find some very interesting for this pick & place project – a solenoid-actuated air valve. In the blood pressure meter, it dumps the pressure from the cuff at the end of the measurement. I was worried that it would only work for pressure but not for vacuum. A quick test showed it's open – air flows – with no power connected. When 5 volts is applied no air flows with either pressure or vacuum applied.

A foot-pedal-operated system will be easier to use tha the fingertip approach. Details soon.

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