When it comes to tools, you'll rarely find any group as innovative as the maker community. With many makers operating on a tight budget, industrial-grade equipment is often inaccessible - but that doesn't stop those with an experimental bent. A great example was published this morning by Thingiverse user Zapta: an Arduino-compatible motorised solder paste dispenser.
For the hobbyist, the jump from through-hole technology (THT) to surface-mount technology (SMT) components can seem insurmountable: no sooner have you got the hang of soldering sticking-out pins and suddenly components require you to solder them directly onto a flat surface. While entirely possible with a traditional soldering iron - until you reach components using packaging like ball grid array (BGA) which have hidden connections you can't reach - the more common method is to solder them using solder paste and a reflow oven.
The principle of using solder paste is simple: you smear the paste, which is no more than grains of solder in a liquid suspension, over the areas of the PCB where solder joints must be made, place the components, and heat the entire board to evaporate the liquid and melt the solder. The application is usually made through the use of a stencil, and we've previously written about the use of low-cost vinyl cutters for producing these. A stencil is great when you're producing a number of identical boards, but what do you do when you're only looking to solder one board - or a number of different boards with unique layouts?
In these cases, you need to apply the solder paste by hand - and it's here that Zapta's creation comes in. Featuring a custom circuit board - which in a classic Catch-22 scenario requires some of its components to be surface-mounted - boasting Arduino compatibility, the dispenser squeezes a regulated amount of solder paste through a metal needle. Designed to be more accurate and easier to use than a hand-plunger syringe, Zapto has released the gadget into the public domain for anyone with access to a 3D printer to try - and it's a great accessory for anyone who has built a reflow oven from a toaster and an Arduino.
This is a motorized solder paste dispenser for soldering SMT boards. The home directory of this project is on GitHub here and it include hardware and firmware design of a compatible controller board that is Arduino compatible (it looks to the Arduino IDE as an Arduino Pro Mini).