Solder paste dispenser for less then $5

thingiverse

Solder Paste Dispenser. I'm attempting to create a solder paste dispenser utilizing inexpensive components from Aliexpress. My inspiration came from https://www.thingiverse.com/thing:384680, and I designed it from scratch. The most significant improvement is the plunger system. You will require: - Arduino Pro Mini ($1.5 delivered) - Stepper Motor with Driver Board 28BYJ-48 ($1.74 delivered) - 5mm to 5mm Coupler ( $1 delivered) - M5 Nut - M5 Threaded Rod 73mm Long - Power Jack - Tactile Button - Wires - Some Self-Tapping Screws You will need a Serial Adapter to Program Arduino. Notes: - Connect the coupler so that the threaded rod pushes against the motor shaft. - If necessary, adjust the plunger scale so it fits into the housing without any drag. - Since the ULN2003 has almost 2V dropout, use at least a 7V power adapter to power the motor. I utilize mine with 9V but also works with 12V; - I designed it for working length, allowing me to put new paste in and extrude all of it. Should work with any solder paste, but I use it with Aliexpress MECHANIC XG-Z40 ($3.5 each). - Do some filing on the plunger and socket so they're smooth. - You can figure out wiring from pictures and Arduino sketch. - Glue the M5 nut in the plunger, so it won't come out during retraction. If the socket is too tight, heat up the nut. Some Throwbacks: - It's uncomfortable to hold. The motor is mounted far from where you hold it, making it unbalanced. - If there's a lot of solder inside the syringe, pressure builds up, and more retraction is needed so the solder doesn't drip out after releasing the button. To Improve: - Change the coupler, making the whole body shorter. Possibly using an elastic hose would work fine. - Shorten the body and move the motor closer. - Maybe change the design to be half the travel, and after dispensing half the paste, take the paste out and place an extender for the plunger. That way, the body could also be shorter. - Add a potentiometer to change speed/retraction length. - Design custom PCB. - Adjust screw hole size and depth, all holes for PCB mounting. - Software could use some improvement. In the end, it improved work applying solder for projects where I don't have a stencil. Designed using Fusion 360 http://a360.co/2A1AaFL