Pick and Place
Once the board has paste applied, the components are placed on top. This can be done by hand or by a machine. Using tweezers is a great way to place components. There is a common fallacy that you need large, expensive machines to make electronics. Not true! A human is quite fast at placing components and the surface tension of liquid metal is such that most components will shift into their correct location during reflow. But humans have a limit to their stamina. After a few hours it becomes harder to place components quickly. The small size of the components also tend to strain eyes.
You don’t need a pick and place machine to make electronics; you need a pick and place machine to build a lot of electronics.
SparkFun started by placing all the components by hand and we still do! But if we have more than about a hundred units to build we use a pick and place machine to allow us to build lots of boards.
A pick and place (PNP) machine is a robotic assembly device that uses a vacuum to lift a component off of a piece of tape, rotate it to the right orientation, then place it on a circuit board. It takes a few hours to setup a machine to build the assembly, but once everything is running, it is very fast.
In a large factory, a conveyor belt often carries the board directly from an automated paste deposition machine into the pick-and-place machines; at SparkFun, we move our boards manually around the production floor.
Bob shows us SparkFun’s new MYDATA PNP machine. It’s pretty awesome.