How would i add a pnuematic lifter to the robot arms ? is it available off the shelf so i can just buy it ? or what parts would i need ? im trying to lift microchips (SO8 packages) to populate a PCB.
Does your arm have sufficient precision to work with such small pieces? Commercial pick/place vacuum devices might be somewhat expensive, but probably possible DIY with some work.
i was thinking of using an AL5D for this. would it not have enough precision ?
You will have to specify what level of precision you are expecting. If you do a board search for “precision” you should find previous discussions on the subject.
Can it do +/- 1mm ?? I was hoping to get within the ballpark of the mitsubishi Movemaster EX RV-M1 (+/- 0.3mm but overkill i think)
highly unlikely.
reality check: do you honestly think if people could consistently place ICs or other SMT parts with robotic arms built from $50 servos there would be a market for machines costing many tens to hundreds of thousands of usd? 
I have been working with the new AL5D, and have been teaching CIM for 9 years. I must agree, there is no way that you’ll get the accuracy you need to populate pc boards.
If you want to simulate it, or use vacuum instead of the gripper, see below. I will be working on this over the next year, so I’ll try to keep pyou posted if you want.
If you want to use vacuum though, you could do what we have done with our scorbot: Hook up a compressor to a venturi valve. We can pull about 18 in of hg at about 80psi from our compressor: enough to hold down a piece of lexan in a cnc machine. You could do what you want at less than 20 psi.
This could then be hooked up through the arm as an input with a simple relay.
The venturi valve can be had for $20.00+, and you could fashion an end effector out of a piece of brass tubing with a suction device on the end. The suction device (rubber cup, accordion-style) should probably be purchased. from a an industrial supply outfit. Check this one out as an example of what is out there: look up smcusa vacuum genarators, and then click on suction cups. Sorry, they wont let me post the link here!
It is just an anti-spam bot thing… have to make 1 or 2 posts without links and wait something like 24 hours. sometimes it gets stuck though and one of the admins has to poke it.
I am very interested in this. 
I have wanted to at least document the process of creating a vacuum gripper for a long time. Just haven’t been able to get it done. 
A shop vac (or two in series like the vacuum formers use) would be an inexpensive vacuum source. I have a compressed air venturi unit and it requires a large compressor to feed it. As to more accurate positioning, one could use a precision sleave over the pick/place spots to guide and align the vacuum tool attached to the end of the arm in the desired position. The vacuum tool could even have a bit of “dangle” to it and the positioning sleave handle the required precision alignment.
Couldn’t one just use an aquarium style air pump, assuming you can find one with an input port? I have found a good place for small vacuum suction cups. Called Anver. Check it out…
if you had a small aquarium pump you could seal it in a container with the output port venting, then add a port to the container as a vaccuum inlet 
probably the biggest issue with the compressor+venturi approach is the pressure to vaccuum ratio required and the fact you need continuous positive flow to maintain the vaccuum. in churd’s example above he is using an 80psi compressor to generate 18mmhg of vaccuum which is about 8psi. to figure out how much vaccuum and therfore pressure would be required for a specific application you need to consider the surface area of your suction cup, the mass of the part you are trying to lift, and any additional force created by acceleration as you pick it up.
it might be an interesting project to use a sensor on the vaccuum side and a proportional control valve on the pressure side of a venturi to see if you could improve the efficiency of using one.
One might use a dustbuster, keyboard vacuum, or other small hand vac. I’d think an aquarium air pump may not have sufficiant air movement to account for small leaks. The below shop vac appears to be small, powerful, and not too expensive.
walmart.com/catalog/product. … id=8477890
google.com/products?q=keyboard+vacuum&hl=en
Check this post: lynxmotion.net/viewtopic.php?f=6&t=6500
No vacuum is necessary for very small parts, just a cylinder like a syringe. This will probably work, but the accuracy for populating a circuit board wont be there. Great for simulation though…
I know, old post.
Churd, have you done any more with your Scorbot?
Alan KM6VV
I have not. We use the venturi to create suction to hold lexan in the cnc machine, like I stated before, but nothing with a vacuum gripper. there are however many who have taken up the vacuum gripper with the Lynx since Jim has come out with his kit.
See the picture below to see how the venturi is hooked up:
The vacuum fixture is made of aluminum with rubber stoppers in the holes that are not used. The part is placed on the fixture with a foam gasket, and the venturi creates the suction to hold the part in place during the machining process.
This was developed by a high school student from Baldwinsville NY about 5 years ago!
