SMT Pick-n-Place System
A SMT pick-and-place system is a machine that can be used as part of Automated Circuitry Making. This machine picks up surface-mount electronics components and places them on a PCB (hopefully in the correct location and orientation).
A fully fledged SMT Pick-and-place system requires:
- Grippers or a picking toolhead (see below or see Gene Hacker's Pick and Place ToolHead)
- PCB holder(s) (see below this page)
- Component feeders
Optional subsystems include:
- Vision systems for compensating for variations in the pick-up of a component, and for detecting correct placement, calibrating against the circuit board dimensions, etc.
- 3D printed holders
- Reflowing in-situ with a controlled hot-air stream.
- PCB changer systems
Code for this project can be found on Google Code.
- Most gripper types rely on suction
- Mechanical grippers
- Ferromagentic parts (e.g. most resistors) can be grabbed with an electro-magnet.
Possible vacuum sources:
- A printed pump (such as this one by Madox, or this one)
- Peristaltic pump (such as Zach's)
- A positive pressure based on the Venturi-effect (can be printed)
- Simple off the shelf USB-vacuum
- A piston that is actuated with a motor (lego, fishertechnik, etc.).
Rubber vacuum tips:
Video (note: downloads a 6mb file)
Holding the PCB
- These kinds of studs with magnets are useful for holding PCBs.
Printing the component and work holders
To make the setup operations easier to perform accurately, the tool holders could be printed just before pick-n-place operations start. This ensures that the PCB is parallel to the XY plane of the cartesian bot.
Usually reflow is done in a controlled oven and the temperature should follow a specific curve. This is to prevent sensitive devices such as LEDs from overheating and to still properly reflow the paste at every solder joint. However, I (Erik) have good experiences with a hot air stream that can be fed from the toolhead, meaning that you can also reflow the boards in the same machine. So far I've been using [this rework station] successfully.