Home-Made Printed Circuit Boards

IS IT "REALLY" possible to fabricate professional printed circuit boards at home?

The short answer is, absolutely yes. The longer answer is that you will need some specialist equipment that may or may not be in your budget. But don't worry, none of it is the uber-expensive equipment that you will see in specialist PCB fabrication plants.

The following photos were taken of a PC board I made at home, from scratch

So most people who see the above photos think I cheated and had the board made at a PCB fabrication service. It would be nice if that was true. Certainly it would have saved me a lot of time, but where's the fun in that- instead I put in all the effort to get this right, even though it took me a few attempts and I wasted a lot of dry film. So with patience, and a modest outlay you can make your own PCBs at home.

So let's break down the requirements for my process:

CHEMICALS

Hydrochloric Acid (HCl). The usual 5l for swimming pools is the one I use
Hydrogen Peroxide (40 volume or better)
Sodium Carbonate (aka washing soda). Granules, not flakes.
Sodium Hydroxide Flakes (aka caustic soda)
Dry film Photoresist (DuPont Riston or the Chinese clones are identical and work the same)
Liquid Photoimageable Soldermask e.g. SANWA SPSR-950-C

EQUIPMENT REQUIREMENTS

Small Orbital Sander with 800 grit polishing pad (Ryobi Mouse is ideal)
UV Exposure unit. Do not bother buying one, as I learnt by trial and error that the commercial units are designed to expose screens. Collimation of the UV source is very important when exposing PCB artwork. I will show in an upcoming article how to make one from scratch using off-the-shelf items from art stores that is correctly collimated for this task.
GBC Creative (or similar) A-4 Document laminator
A means to cut FR-4 PCB material to size (shears, Dremel, or guillotine)
Large plastic dish for developing and etching
PPE equipment (mask, gloves, and respirator)
Desk top CNC machine e.g. LUNYEE 3018
PCB milling bit set (UNION TOOL) 0.3 to 1.2mm. Please do not use cheap Chinese sets, they don't last and do not finish the PCB off properly, they tend to burr pad edges and vibrate when milling.
A screen printer, and silkscreen frame fitted with 200 mesh screen or finer

SOFTWARE

GCPREVUE to combine various Gerber layers and drill files into a panel
FlatCAM to generate CNC program for the drilling and routing
Candle to drive the CNC machine and run the CNC programs

SERVICE PROVIDERS FOR FILM OUTPUT

To create accurate PCB patterns, especially when you intend to use a CNC to drill the PCB, it becomes important to use accurate film negatives for the photographic work. As I have discovered, using home printing methods are just not good enough. Therefore it is essential to have access to a film output service or bureau.

Generally speaking, most PCB manufacturers do not have a problem supplying film negatives from Gerbers for a fee to the hobbyist. In South Africa, however, the situation is that the anti-competitive attitude of companies still prevails and ALL the PCB manufacturers in South Africa will tell you to sod off, except one.

To this end I have provided details below for those that are able to assist with film negatives in South Africa:

                         Graystonite
                         SHOP 5, 29 CENTRAL AVENUE, EASTLEIGH, GAUTENG, 1609, RSA
                         [email protected]
                         Tel: +27 076 068 0129

                         Master Circuits
                         Unit 8, Palm River Industrial Park, 1 Devon Rd, Pinetown, New Germany, 3600, RSA
                         Tel: +27 31 700 4776

I am currently fully documenting my process, hence more pages on specific aspects will be published in due course.

GALLERY