Before starting on this robot we looked at the various commercial soldering systems that are available. Wave soldering machines would have been impractical as the connector is on the top side of the board next to the surface mount components. Wave soldering would also coat the full length of the pin in solder which we don’t want to do as it would make it more difficult to stack the boards. There are several commercial soldering robots available and we got quotes for some of them but we decided that they were either too big, too slow or too expensive, with most costing more than a new car. In the end we decided that what we wanted was so specialised it would be easier and cheaper to make one ourselves.
When making the move from prototype to production, there can be an awkward valley to overcome: making ten of something is easily done by hand while making 100,000 of something justifies the expense of a commercial-grade machine or service, but what is a maker to do when he or she only needs 500 or so? The obvious choice is to trawl the marketplaces for fifth- or sixth-hand outdated machinery, but Brian Dorey opted for something a little trickier: hand-building a custom soldering robot to help produce his through-hole technology (THT) circuit boards. Brought to our attention via Hackaday, the machine is a wonder of engineering: rather than using a wave-solder method - where the circuit board, components pre-fitted, is floated over a sea of liquid solder - the robot solders the components exactly as Brian himself would, using hand-held soldering irons clenched in its robotic fists. While Brian admits that the machine "is still very slow," he claims that its performance will be tweaked post-testing - and has even added Bluetooth modules to the design so that multiple soldering machines can be slaved to a master unit for larger-scale production jobs. The project is well-documented, and for anyone looking to follow in Brian's footsteps is published under the permissive MIT Licence on GitHub for forking and replication.