DIY Soldering Device Makes It Easy to Dispense Paste Without the Mess
This low-cost, 3D-printed paste dispenser features a mini DC motor and gearbox along with an M3 shaft secured by a pair of axial bearings.
When it comes to surface-mounting electronics to PCBs, you can either solder each component one at a time using an iron, which can take a lot of time, or can cover the pads with solder paste, add the electronics, and throw it into a reflow oven. That is, of course, if you are lucky enough to have a stencil. If you choose to go with the former, embedded systems enthusiast Kevarek has designed a low-cost paste dispenser that can make the job easier.
Kevarek assembled his paste dispenser using some parts he sourced on eBay, including a mini DC motor and gearbox (100RPM), along with an M3 shaft that is secured by a pair of axial bearings, which is packed inside of a slick 3D-printed case. The threaded M3 shaft engages a syringe filled with solder paste, which is controlled by an STM32 that provides adjustment and flow rates, as well as performing a paste retraction to avoid applying excess material.
The dispenser’s control box is outfitted with a power switch, a display, and three control buttons, which can be used to control paste flow and other metrics. There is another button on the handheld unit to control the flow rate as well. Kevarek has uploaded a detailed walkthrough of his inexpensive paste dispenser on his project page, complete with schematics, files, and links to code for those interested in recreating his build.