First test of my ShapeOko pick and place prototype

First test of my ShapeOko pick and place prototype

Postby potatotron » Thu Jun 28, 2012 4:15 am

http://www.youtube.com/watch?v=Zsas4URs-RU

This is the first test of my pick and place machine, placing size 1206 resistors.

The software is GRBL on an Arduino Nano being fed instructions via a small Perl script I wrote.

The hardware is a ShapeOko frame, 3 NEMA 17 motors from SparkFun, 3 Pololu A4988 drivers, a fan to cool the drivers, a 28V 8A power supply, an aquarium pump modified to be a vacuum, an air solenoid to control the vacuum, and vacuum head. The solenoid is connected to GRBL's "spindle" port via a power transistor.

I followed these instructions to convert the aquarium pump into a vacuum:

http://garage-shoppe.com/wordpress/?p=109

but I could never get that working (not sure if they revised the hardware or I'm just incompetent), so I siliconed the tubing to the pump's air intake.

The vacuum head is from the same author:

http://garage-shoppe.com/wordpress/?p=164

but I didn't bother with a body; I've just got the Luer adapter connected directly to the ShapeOko's Z axis MakerSlide.
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Re: First test of my ShapeOko pick and place prototype

Postby potatotron » Thu Jun 28, 2012 4:35 am

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Re: First test of my ShapeOko pick and place prototype

Postby PLHS54 » Thu Jun 28, 2012 5:07 am

That's very neat indeed. This may be a dumb question, but I'll ask anyway. Is Perl Script your commands to your motors, like for machining we use g-code? I'm also curious as to why you used a larger power supply, is this so you can power your vacuum?
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Re: First test of my ShapeOko pick and place prototype

Postby potatotron » Thu Jun 28, 2012 5:38 am

Sorry, I should have explained that better. The Perl script is just generating and sending G Code. (I could have used Processing or any other scripting language, I'm just a fan of Perl).

The part placements are basically the same sequence over and over, with slight position changes each time. Using loops in a scripting language made this really easy.

You're right the power supply is oversized for now; I have plans to add a lot more to this system so it's for future growth.
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Re: First test of my ShapeOko pick and place prototype

Postby jahn » Thu Jun 28, 2012 10:40 am

Seems very nice.Can you please let us know more about vacuum head control?
Thanks
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Re: First test of my ShapeOko pick and place prototype

Postby rustythebear » Thu Jun 28, 2012 5:11 pm

Thanks for the video. You have enlightened me on a certain aspect of pick and place.
I bought the $40 P&P vacuum pen on ebay. I comes with a adjustable vacuum amount , two pens and two heads.
Now I see it for $30 with free shipping, oh well. I didn't want to invest the time or money into
modifying an aquarium pump.

I have seen other pick and place videos with the compnent reels mounted and a feeding mechanism to
advance a reel after a component is removed. The first thing I noticed in your video is you just laid out a
strip of the compnents for your test and moved the vac to go and get them. It occurred to me that if
I do this with all of my components, to build a panel of small boards, I don't have to worry about a fancy
reel and feeding mechanism. I just need to lay out the strip and let the system know where the first component is located.
Seems a simple matter of generating the X/Y for the source parts and extracting its X/Y from the board file to get its destination.

Thanks for sharing,
Rusty
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Re: First test of my ShapeOko pick and place prototype

Postby potatotron » Thu Jun 28, 2012 6:48 pm

Seems very nice.Can you please let us know more about vacuum head control?


Sure.

The first pic is the aquarium pump, I glued a connector to its air intake for the vacuum.

The second pic is a T connector going to the air solenoid, then to the vacuum head. At first I tried the pump on one side of the solenoid and the head on the other, but it doesn't work that well because even when the solenoid is blocking the pump there's no way for air to get back in to the head hose to release the part. So now when the solenoid is closed the vacuum goes straight to the head, and when it's open it's a path of lower resistance so the head loses its vacuum and releases the part.

The third pic is the vacuum head attachment, which is very much a hack for now; it's just held in place with some wire wrapped around some insertion nuts

(it looks like I can only upload 3 attachments per post, so I'll add another with the electronics in the next post).
Attachments
IMG_1599.JPG
IMG_1599.JPG (76.64 KiB) Viewed 3154 times
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IMG_1598.JPG (93.9 KiB) Viewed 3154 times
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IMG_1597.JPG (85.79 KiB) Viewed 3154 times
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Re: First test of my ShapeOko pick and place prototype

Postby potatotron » Thu Jun 28, 2012 6:59 pm

This is a picture of the components to control the solenoid. A wire runs from Arduino D12 (GRBL's Spindle Control pin) to a 1K resistor, which then goes to the Base pin of BC337 transistor (I don't think there's anything magic about that transistor; it's just what I had available). The Emitter of the transistor is connected to common ground, and the Collector goes to the solenoid.

The other wire of the solenoid goes to a 68 Ohm 5W resistor, which then goes to the +28V of the motor power supply. The solenoid itself is 12V and this was a quick hack to make it work without burning itself out. Eventually I'll get a voltage regulator to turn the 28V into 12V without wasting so much power into heat like the resistor does, but for now it works.
Attachments
IMG_1600.JPG
IMG_1600.JPG (147.66 KiB) Viewed 3154 times
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Re: First test of my ShapeOko pick and place prototype

Postby potatotron » Thu Jun 28, 2012 7:06 pm

I have seen other pick and place videos with the compnent reels mounted and a feeding mechanism to
advance a reel after a component is removed. The first thing I noticed in your video is you just laid out a
strip of the compnents for your test and moved the vac to go and get them. It occurred to me that if
I do this with all of my components, to build a panel of small boards, I don't have to worry about a fancy
reel and feeding mechanism. I just need to lay out the strip and let the system know where the first component is located.
Seems a simple matter of generating the X/Y for the source parts and extracting its X/Y from the board file to get its destination.


I've actually ordered a feeder

http://www.goodluckbuy.com/smt-smd-feed ... 5-way.html

but it won't be here for several weeks and I got tired of waiting. On YouTube I found someone else who just laid the component tape down and decided to try it myself. It looks like SMD components are spaced 4mm apart on tape so once I got the first position (in my case X=102, Y=177) the rest were easy (second is at 98,177, third piece at 94,177, etc.).

For a small number of parts it looks like this will be much easier, but I'm going to be using several hundred LEDs per board so I'm going to have to bite the bullet and figure out a reliable feed sequence.
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Re: First test of my ShapeOko pick and place prototype

Postby Digitalmagic » Thu Jun 28, 2012 7:17 pm

Very cool.
Later on, how do you manage to have the SMD components stick on PCB while releasing pressure?

Also, where can we find this air solenoid? BOM syndrome :D !
Thanks.
s/o #650 - Wish my digits are ... magic!
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