PCBA: Simple and Easy Home Made Stencil for SMD PCBAChao
After tried using toothpick to place the solder paste, a home made stencil will be a good solution to start a small batch of production. This tutorial only takes some simple materials which you can get everywhere: beverage soda can, toner transfer paper and machine, some etch solutions. You can get the soda can at your local store and the rest from us.
Firstly, it will be nice to check this video to get overview about how to do it.
Step 1: Cutout and prepare aluminum from a beverage can.
This aluminum is very strong and flexible. It does not bend easily and has shape memory. It will keep its cylindrical shape but you can gently unbend it to a flat shape. Unfortunately the interior coating prevents etching. So sand the interior protective coating in the spot you will transfer the toner, to a shiny mirror like surface. Also sand off the outside paint, it helps to see when the pads are coming through the other side. You will need to experiment what sanding materials you like. I used grit 400 and 2000, also the finest steel wool I had.
Step 2: Print PCB layout onto toner transfer paper.
This step could be complex, the print has to be original size, print in black for not removing, no-print for etching, which should be the SMD padding. So it’s probably the printing has to reverse the color black and white.Make sure it prints in the highest resolutions and density to ensure it is the most black.
Step 3: Transfer the toner to the aluminum and etch.
The most easiest way is use toner transfer machine, tape the toner transfer paper on the aluminium sheet firmly, and leave into the machine. The alternative solution is to use a iron to transfer it. The etch is not difficult.
This tutorial refers to lowpowerlab site, for full article please see here.