Small PCB Chemical Etching Machine

An etching machine that will fit on your shop bench..

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A small machine to etch PCBs which will fit on a bench and quickly etch PCBs using your favorite chemical etchant..

My vision for this device will be a sealed machine... you unlatch, open the door, insert your board which is ready to be etched... Press a couple menu buttons, and the machine etches the board... then lets you know when it's done.. First thoughts are something like a carwash with rotating agitators, possibly fed by sprayers or just a feed line to soak the material...etc...which will etch the board without much chemical waste....or mess (outside the machine)...

Picture on left is not a good representation... =D

The challenge will be automating the device so it 'knows' when the board is done... My first thought was some overly complicated system where it runs a short etching cycle, then rinses and checks with an IR camera or something to 'see' if the lines are distinct enough, if not continue, etc.... Another would be just a simpler system where it etches for a short cycle, rinses...then shines a laser across the surface and measures the distinction... if the trace edges are sharp enough, it knows its done...

Obviously, this is going to take some experimenting and playing around with... but I think overall, the outcome will be worth the effort.. I'd like to make it as low maintenance as little mess as possible, and as simple as can be.... liquids are tough to deal with to begin with, let alone acids and other toxic chemicals... so that'll be another challenge...

If anyone knows of any cheap small pumps capable of pumping the muriatic acid/hydrogen peroxide mix, I'd be happy to see... I've seen a lot of back and forth on SHURflo pumps...

  • ​Thoughts forming...

    fl@C@04/02/2015 at 01:22 0 comments

    Ok... so my head has been bouncing around trying to figure out how to make a small desktop machine that handles acid and other liquids without making a mess....... DONE..

    I'm pretty sure I have a concept that will work out.. I'll do some renderings to illustrate the idea...but basically... I'm thinking about building this into a PC case again because they're easy to get ahold of and look cool, plus they have tons of space to mount stuff, etc...

    So, the idea is.... Two one inch thick blocks of HDPE... milled out in the middle similar to how you'd see cooling blocks for PC water cooling systems... A hose connector on each end, top and bottom.... the PCB to be etched fits inside the channel.. The whole thing is like a clam shell that closes down on the PCB and has EPDM seals around the edges...

    The blocks will also have rotating 'brushes' that contact the surfaces of the PCB to agitate...And will probably be driven by magnetic couplings from the outside of the blocks.. HCl/H2O2 solution is flushed through and over the pcb in a rotating cycle with a shurFlo pump in the first cycle...then a valve switches to water and rinses.... an optical reading is taken to determine sharpness of the traces/edges and if they're below the threshold a short cycle continues until it reaches the defined level... then the system rinses thoroughly and signals that it's done... I thought about a drying cycle, but I'll get to that... Who knows.. :)

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badger wrote 03/14/2015 at 11:38 point

Santoprene is a material used in pump components which has good resistance to acids and H2O2. A quick search indicates some of the Shurflo pumps have santoprene diaphragms.

Also, peristaltic pumps can sometimes be found cheaply (often as dishwasher spares) and can be fitted with santoprene tubing. The downside with these is the flow rate is usually very low but they do produce good pressure. It may be possible to use a them with some kind of nozzle for your application. 

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fl@C@ wrote 03/15/2015 at 11:59 point

Hey, thanks Badger!  I'll look into that..  I thought about peristaltic pumps..and considering the costs for shurflo, etc.. it might be worth it to try 3d printing a decent one..  Definitely worth experimenting with, thanks for the info!!

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