Pick and place without the CNC

Pick and place (PnP) machines are the linchpin on which modern electronics manufacturing rests. A PnP is a special kind of robot with a vacuum end effector designed to pick up SMD (surface-mount device) components and place them on a PCB for soldering. But for hobbyists, they’re usually overkill. So, John LeClair bridged the gap with these manual PnP vacuum tweezers.

This is just a PnP machine, but without all that fancy CNC robot stuff. With this, you’re the robot and you hold the “end effector.” You likely won’t have the precision or work ethic of a robot, but you’ll be able to place SMD components on your board without resorting to sticky, staticky, pinchy tweezers.

The end effector here is just a small Weller handheld tool with flat cup nozzle. All of the interesting stuff is related to controlling vacuum. An Arduino UNO Rev3 handles that by sending power to a 12V diaphragm air compressor pump working in reverse to pull vacuum. The Arduino controls it and a solenoid valve through MOSFETs. By modulating power to the pump MOSFET via PWM, the Arduino can control the pump’s speed. 

For ease of use, there are only four user controls. The first is a power switch to turn on the whole machine. The second is a potentiometer to set the pump speed. The third is a potentiometer to set the amount of time the pump stays on. The last is a footswitch to activate the pump.

When you’re ready to grab something, simply depress the footswitch and the pump will come on. Then use the tool to start picking up and placing your SMD components.