The current approach being considered is to use a Delta configuration robot to position the pick and place head over the board workspace.
An example of a similar robot is shown in the following YouTube video:
http://www.youtube.com/watch?v=FgnxBaFFDi8
I was looking at some ball joints and see that the swivel range is only 15 degree and that the better quality joints with steel ball and bronze bearing are quite expensive. I propose custom universal joints with popular size ball bearings, which we can buy
for $1.95 each. With 4 bearings in each joint plus machining of the U-profile, we can likely cut the cost and increase the life time of the joints.
I made each arm 500 mm long, aiming for a 450mm by 450mm travel area.
http://download.codeplex.com/Download?ProjectName=wikiplacer&DownloadId=356216
After some more hours on the drawing, my robot moves only up and down, but not sideways. I guess Alibre is not sophisticated enough. However, I'll place some feeders in the drawing to pretend I'm done.
http://download.codeplex.com/Download?ProjectName=wikiplacer&DownloadId=357862
Some more time spent into the drawing, I find the 15 mm linear rail likely an overkill and will look for smaller rails and less expensive solution.
Else, the feeders require a slot in the base for the empty tape and cover tape cutter/disposal. The two rails for the board could have a fixed side and a moveable side. I guess, the industry standard is front side fixed with boards conveying from left to right. In this case, the feeder bank in the rear will have a longer travel distance to the board than the one in front.
http://download.codeplex.com/Download?ProjectName=wikiplacer&DownloadId=358103