Printed Circuit Board (PCB) Etching Station
Description
There are many ways to make your very own printed circuit boards without working for a huge electronics company or a university laboratory. Members who wish to make their own PCBs typically use one of two chemical-based methods to etch copper-clad boards into specific patterns and traces. The chemicals used are acidic so proper care should be given at all times.
Steps
Design your board in DipTrace or a similar program
Print your design out on a sheet of special laser toner transfer paper
Prepare a blank copper board and wash any debris from the copper using isopropyl alcohol and a rough dish pad (Brillo, etc.)
Tape your design to a copper sheet and transfer it by heating the surface and applying pressure (the shirt hot press and badge laminator located by the etching station work great for this)
Check for breaks in traces and pours, most can be touched up with permanent marker (red seems to work best)
Everything that is not covered up by the iron-on transfer (a.k.a. your etch resist) will be consumed by the acid
Etch your board using one of the two methods below
When finished, remove your board, and wash with water then rub the etch resist off with a dish pad and Goof Off or isopropyl alcohol
You can also tin plate the copper when finished to
Observe chemical safety protocols at all times and if you don't know how to handle something, don't do it!
Ferric Chloride Method
Ferric chloride is a dark brown, corrosive liquid that basically eats copper
Very little chemical etchant should be used, just enough to submerge the board, 1 fluid ounce of ferric chloride can remove 3.5 square feet of copper from a board
Use a shallow pan on the hot plate and agitator to heat and stir the solution as you etch
It can be messy and the ferric chloride will stain almost everything including skin and clothing
Ferric chloride is also a pollutant and should be disposed of as you would CFLs or oil or other hazardous materials
Muriatic Acid Method
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Muriatic acid (a.k.a. hydrochloric acid) is typically used as a pool cleaner and can be found in most hardware stores
Hydrogen peroxide is a cheap, common antiseptic
When combined, they form a moderately strong acid/etchant (always add acid to water!)
Using one part muriatic acid to two parts hydrogen peroxide, submerge your board for two to five minutes while aerating the solution
This has been the preferred method since the chemical etching tank was built in September 2011
The etchant will turn green as the copper is dissolved
Aerating the solution while etching helps speed up the process
This solution can also be reused multiple times; add more hydrogen peroxide if the solution appears “too green” in color
Like ferric chloride, this solution is also a pollutant and should be disposed of as a hazardous material, however this process generates much less waste by volume than the ferric method
Available Equipment
Techniks-brand Press-N-Peel PCB Transfer Film (blue paper, print on matte finish side, not shiny side!)
Hot plate (never operate above 'LOW' setting, it will melt plastic trays easily!)
Badge laminator - used for iron-on transfer from laser toner paper
T-shirt hot press - used for iron-on transfer from laser toner paper
Agitator table - used to stir solutions
Laser printer - necessary for PCB transfer paper
Dremel drill press stands - used for drilling vias and through-holes in completed boards
Chemical etching tank with aerator and aquarium pump
Available Chemicals
Muriatic acid - etchant
Hydrogen peroxide - oxidizer
Ferric chloride - etchant
Isopropyl alcohol - cleaner/oxidizer
Paint thinner (acetone) - cleaner
Ammonia - cleaner
Goof Off (xylene) - cleaner
Tap water - cleaner/diluter
Tin It - tinning solution, helps solder stick easier to the board
Location
Current: Planned for Vault 16, PCB Etching Lab, Lenox
Previous: Lab, Chase
On lend from
History
12/01/10 - Arrived at Makerspace
03/15/11 - Brant Holeman built a chemical storage shelf and posted hazard signs
09/15/11 - Tom Gralewicz built a vertical etching tank
12/31/12 - Moved to Lenox, originally planned for Vault 16
??/??/13 - Chemicals located in plastic hood in Wash Sink Room
Notes