Your gonna hate me for this
I am an SMT Operator at a pcb manufacturing plant in Davenport Iowa. When we build our boards, they go through an oven. At the end of the oven, they pile up unless we get there and manually remove them. We are often late, and parts are knocked off the boards.
We are considering building a robot arm controlled by a pc to handle this problem. The arm would clamp down on the board when the board enters the grippers and hits a sensor. The board would then be moved to a rack that holdes 20 boards. The rack has 20 slots for boards with 1/2" between the slots. So, we will program the arm to pick the board, move it to the rack (+1/2"), release the board, and return to the waiting position at the end of the oven. After 20 boards, the pc will make a sound (mp3,wav,ect) to let us know that the rack is full and needs a new one.
Sounds easy huh? Well, we know nothing about what we are doing. Figures huh? Anyway, our shop say's they can make the arm out of light material. The boards we are picking up arn't very heavy, but we would like to play it safe and be able to pick up 1/2 pound.
Can anyone tell me if they are familure with the SCON SB 018 servo controler board? Seems pretty low cost, and will control up to 8 servos. Also comes with the programming software. Looks easy for beginners.
We know we can't use rc servos because of there lack of power.
(Ha! see? We do know something)
We have send email to there tech support to see if there product will handle more heavy duty motors, but haven't heard back from them yet. (Just sent it today)
You can check out the SCON products at WWW.SCONCON.COM
If this is totally goofy, let me know. We are open for anything and everything you can tell us.
I know there are arms on ebay like the Teachmover and such, but we are kinda pumped to do it ourselves. (If we can)
Thanks in advance for putting up with probably the stupidest message you have read today.
I think as far as the mechanical side, I would not use a robot arm. I would use 80/20, all you need is a pick-&-place. Contact http://www.8020.net/Default.asp and see what they offer.
As far as software I'm not sure, maybe 80/20 will offer a good suggestion.
I think a robot arm is just asking for a headache down the road. All you need are linear moves, you only need 2-axis.
Also, I think with 80/20 you can do as much of the work as you want, or you can let them build the entire setup for you.
A robotic arm certainly would have "cool" value, but as Switcher indicates, it's likely more complicated than required for this relatively simple job. If my mental image of your problem is correct, then I'd make the rack mount on a vertical axis near the output of your machine. Then you could make a gripper/slider mechanism on a linear rail that would grab the board just output and slide it into the rack. Then you could index the rack up (or down) to the next position.
Having said that, building a robot arm certainly would be fun. (In a past life, I worked in some really fancy robotics. In fact, that's the job that got me into machining and CNC as a hobby.)
One more reason for building it as simple as possible: Once you get something working, you can always improve it. But if you do something too complicated for your first project, it can be discouraging. The system I described still has several interesting challenges in it for a first-time CNC project.
Not sure if this helps, but if you go to GOOGLE, select images, and search for: "pick place robot" you will find 100's of pictures of applications for such robotic systems!
May prove usefull in choosing a simple design and proper components!
Hope this helps,
Last edited by widgitmaster; 11-25-2006 at 09:04 PM.
Get message "This page cannot be displayed" when selecting Movie.
Originally Posted by widgitmaster
WOW! You guys are fantastic! I posted my problem at 12:30am and by 11am I have 6 replies. Thanks all.
I checked out the 20/80 site and grabbed there movie to show the boss. You are all correct, I probably was doing the 'arm' for the cool factor. Thanks for waking me up before I got in deeper than I needed.
Recieved a message back from SCON tech, and they said there controller would not work anyway as it was too "sloppy" and each complete cycle of the operation would be a little off target. After a few cycles, I would be in a world of hurt.
A lot to think about, I'll let you know which route we take. (and probably need more help).
And I understand. KEEP IT SIMPLE STUPID. Being our first project, we need to have that on a sign posted on our wall.
Again, thanks all.
Hope you solved the board handling problem. You may want to take a look at http://www.dovebid.com from time to time. They auction off lots of stuff from the PCB industry.
Tom what did happen with this, and what did you decide in the end? I hate when people don't update!
M2c, I'd just build a rotating table at the end of the line. Board goes through IR beam onto rotating table. Table rotates. Next board goes through...table rotates...next board etc etc. Number of boards fitting on table is governed by table diameter. Nice and simple, although it could end up taking a bit of space.
yes a convayor would have a number of advantages , 1 it gives the boards time to cool so the components wont shift during production and a convayor based stacker packing unit would do the rest
a robot arm may look the koolest solution but is rather over kill for a task better performed by dedicated kit
and you may still have the same problem with component displacment because of the speed and angle movements of the arm , if the board's are still hot
a convayor will sort of naturalaly detect the board and it sort of falls into the wanted position
but a robot arm will need a rather complex method to detect where the board is to direct the arm to that point and secondly if the point you want to use the gripper on the board is right , or it will just eather shift some components out of the way to get a grip of it
robot arms actualy have a limited number of uses in industry
and a simper solution is often available
I also work in the electronics (not personally at the SMT-department)..
We use a conveyor which moves the boards to a ESD stacking rack (which can move up and down to specific positions) where the boards slide in place!
We have a complete SMT-line, stacking-rack at the beginning, this is where empty boards are collected from the rack, then they go through a machine which screens the pasta onto the SMD-pads, then (still fully automatic) the board goes to the Pick-and-place machine which places the SMD-components at (ridiculous) high speed onto the pads.. After this, the boards go into the oven (which actually solders the components into place), after this the boards go onto another conveyor directly into the stacking-rack at the end..
Beautiful piece of equipment!!