Instructables
Picture of Printed Circuit Board (PCB) Sprayer Machine
DSC_2886.JPG
Untitled.jpg
P1000503.jpg



How would you like to make a single or multiple Printed Circuit Boards in less than 2 minutes?

Hey again.  Hope everyone enjoyed my last Instructable on how to make a grappling hook launcher.  Today I go down a slightly different path of creation.

This project has been in my mind for quite some time and I thought it would be a good time to finally build it.  The idea began when I was tired of spending 25 minutes sloshing a Printed Circuit Board (PCB from now on) around in a plastic tray and waiting for it to finish etching.  It was messy and wasted a lot of time.  I began to search for an alternative and did not get much farther than a bucket with a fish tank bubble machine and perhaps a heater.  Sprayers seemed like the most practical solution but the commercial available ones cost thousands of dollars and there was no guide that allowed someone to create one to use in their own shop. That is, until now.

I would like to present to you my Printed Circuit Board Spraying Machine that anyone with basic tool skills can build.  Plenty of people have published and built CNC machines.  Even some 3D printers have started to pop up.  Countless tools and devices for creating projectes have been published on Instructables and across the internet.  All of these devices use circuit boards and most can be created using a PCB.  However, gone are the days where one needs a messy tray and needs to spend almost a half hour making them.  The PCB Sprayer produces them in less than 2 minutes, can produce multiple PCBs at a time, continuously produce them, and then clean them afterwards.  It is like a little factory in your workshop.  This machine is a great addition to any maker's shop and is an absolute blast to build.  You can produce PCB's on demand with ease and not have to spend thousands on an industrial machine.    Where else can you improve your wood, plastic, electrical, plumbing and sketching skills?  

I have organized each step of this Instructable into 5 sections to try and make it as clear and easy to follow as possible:
1) Step Aim: where I discuss what we will accomplish/create in this step.
2) Tools: which tools will be required to perform this step.
3) Materials: what materials from the part list will you need in this step.
4) Directions: step by step directions for this particular component's construction.
5) Tips: where I make note of any problems I ran into and ways to avoid them during your building process. 
Of course, there will be countless photos, diagrams, drawing, and links to supplement each step and avoid any confusion (you may need to view full size to see all the dimensions and notes properly).

I have also included the Sketchup files (.skp) if you would like to view those.  Sketchup is a google 3D design product can be downloaded for free here.

As for the ShopBot contest, if I can build a grappling hook launcher with a fire extinguisher and a Printed Circuit board Machine from a few sprinkler heads, who knows what I could do with a ShopBot?

Without further ado, I present to you the internets first do-it-yourself, complete step-by-step guide, to building your own PCB Factory.
As always, have fun building and feel free to email/message/comment with any questions you may have.  I recommend looking at the whole intractable first before beginning building so you can get the full picture of what we are creating.  Enjoy.

Again, my name is Christian Reed and I am a Mechanical Engineering student at MIT.  My blog with other creations can be found here.
 
 
Remove these adsRemove these ads by Signing Up
MoonaA1 month ago

Great....

http://rushpcb.co.uk/ delivers high quality products(Printed circuit boards, flex and rigid) all at a very good price.

giuly7310 months ago
hello great video you are a geniuse!!! I understood that it is for pcb, but I have a question please... I use spray guns to paint my wooden products, small pieces.
Can you find a method with spray guns but automatized, like cnc or similar that tries to paint wooden small pieces? Please I know that it is possible to do, but I don't know how. Given the way that are pieces of wood, water it isn't possible because of wood, but if you could find a method to overcome this issue you will do to me a great favour.
Please I would pay, because if i had to buy cnc spraying machine it would be much much money, but I need for small projects.
Thanks in any way
Regards
;-)
Etching spray tank project cost less than 25 U.S. dollars
01photo-nahid@2012.jpg02ohoto-nahid@2012.jpg03photo-nahid@2012.jpg04phptp-nahid@2012.jpg
Etching spray tank project cost less than 25 U.S. dollars
Hi - in the past few days after reading the work in this design started work according to the material available I have worked a small tank and without measurements completed in a week and stayed on the examination and then work to Tver living me - thank you so much for this work again
Hi - very good job summit creativity etching machine
Snapshot_20130220_1.JPGSnapshot_20130220_1.JPGSnapshot_20130220_1.JPGsch.TOT-SOS. SGINL.bmppcb.TOT.SOS. Sginl.bmpSnapshot_20130220_1.JPGTOT-SOS. SGINL.pngSnapshot_20130220.JPG
Tangoforce1 year ago
Just a quick question, what sort of pump did you use for pumping that etchant around? Presumably it's one with a plastic mechanism inside?
Tangoforce1 year ago
Dude seriously, you rock!

Brilliant design, love it to bits.
brcoenen1 year ago
This idea is great, but seems to be more for single sided pcb's. Can i add sprayers to the opposite side of the echant tank for double sided pcb's?
crreed (author)  brcoenen1 year ago
Yes, that shouldnt be a problem.
crreed (author) 1 year ago
Yes, that shouldnt be a problem.
Lindie2 years ago
This is awesome! Great job!
Awesome!!!!!
Mtaram2 years ago
I loved the project. Might someday build it for my self. Not sure though that I would be using it that often but will be a great addon for prototyping PCBs.
fotbr2 years ago
Instead of epoxy and goop, you can use glues made for acrylic; they act as a bit of a solvent along the joint and provide both structure and water/liquid-tightness. Your pieces do need to be cut accurately and fit together well though.
reed922 years ago
Great instructable!

I have only one question. Why are the pcb's mounted vertically? I would think placing them horizontally with the sprayers above would result in less undercut. Am I right? Or would it not make a significant difference?
crreed (author)  reed922 years ago
It would be harder to place the board in the machine and etchant would pool up on the board and not allow for as much etchant turnover compared to it mounted vertically.
This is an excellent idea. Great job! It appears that with a few minor changes, this machine could be used to do chemical plating as well. Just a thought. - RA
klee27x2 years ago
This is insanely awesome. I wonder how the pump and other parts and fittings will handle the corrosive fumes.

Also am curious what is the thickness of the copper in your testing?

I etch with CuCl2 in a bubble tank. It takes me about 10-15 min to etch a half oz board. 20-30 min for a 1 oz board, and 40-50 minutes to etch a 2 oz board at room temp.

Just a note on the etchant used. Muriatic and peroxide is an insanely fast etchant. But the solution won't actually get faster when more Cucl2 dissolves into it, because the peroxide breaks down, spontaneously. If you keep adding more, you'll end up diluting your etchant too much. If/when you reach a concentration of Cucl2 high enough for etching, it'll be much slower than your starting etchant.
crreed (author)  klee27x2 years ago
Hey thanks a lot. Actually the entire machine is made out of non corrosive parts besides a small part of the pump assembly but even that has a large amount of plastic parts. As for the chemistry behind it, you may be right, I was just referencing someone else's work with the chemical composition . Also I'm not too sure about the thickness but when I compar the same type of board in still solution vs the machine, the speed went from 25 minutes to about 2 minutes.
The acrylic is reasonably OK but commercial PVC is usually plasticized to provide flexibility. The peroxide will eventually degrade some plasticizers and the PVC will become brittle. The thicker sections though will probably last for a very long time. Some nylons are prone to oxidation too but most are fairly stable nowadays. You would want to avoid PP and PET as they can have oxidation problems that are accelerated by UV. Polyethylene and silicon rubber are best for this sort of work. You are certainly helping the situation by cleaning out the system immediately after use.

About 35 years ago I was working as a chemist in a tertiary institution and I was given the job of mixing hydrochloric acid / hydrogen peroxide etchant for the electronic department. They supplied me with the formula and that particular mixture etched a circuit board in about 60 seconds or less with a spectacular reaction. I can't remember the exact formula now but it used conc.H2O2 and conc.HCl.
The etchant was fast but as I recall it could only be used once; mind you they were doing static etching with a small etchant volume to area ratio.
Muriatic acid is a dilute form of hydrochloric acid and hydrogen peroxide comes commercially in a number of different strengths. I was not able to find the H2O2 strength you used in your notes but it was probably 30 vol.
I am not surprised it etched through the sharpie pen lines; not all resists are suitable for HCl / H2O2 etchants so it is best to do a test first.

Good for you using gloves and glasses. One additional safety note, peroxide mixtures often release oxygen while in storage. It is a good idea to check or control the head pressure in storage containers and keep them cool. We had one bottle of peroxide etchant pop while in storage. It was fortunate it was in a fume cupboard so the damage was minimal. 
klee27x crreed2 years ago
Well, I hope the pump can handle this. I always thought you'd need to use compressed air to do this right, like a paint gun. And air compressor = loud, so I never really pursued this kind of tank. Nice work!

Keep us posted on the practicality. I'm afraid that the volume of etchant you use will not be good for that kind of etchant, because of the short working life of the H2O2. If my fears are realized and you end up trying a more traditional etchant, be sure to give us a heads up on the effectiveness using something like ferric or cupric chloride! I imagine it would be easy to add some additional aeration to keep the speed insanely fast!
crreed (author)  klee27x2 years ago
It does not have a short working life and can be titrated to regenerate the solution. It seems to me to be a very practical and inexpensive solution. Try looking at this link for the exact science of it but it will not go bad and can keep being regenerated.

http://members.optusnet.com.au/eseychell/PCB/etching_CuCl/index.html
klee27x crreed2 years ago
Yeah, that's cupric chloride. But you have muriatic acid and peroxide with just a tiny bit of cupric chloride. muriatic is a terrible etchant on it's own. It needs a strong oxidizer to work.

Peroxide has to remain pure to be stable. There are additional buffers added in the bottle to keep it good, even, at a measly 3%. Super high concentrations can be achieved in clean environments, but they have to be kept completely sterile.

The metal ions in your used etchant catalyst the breakdown of peroxide. Once it's gone, all you're left with is water. So in a day or two, all you'll be left with is 1:2 ration of muriatic acid and water, with the scant few copper ions in it that won't be enough to etch worth a darn.
klee27x klee27x2 years ago
Oh, one thing you might consider is to put handful or two of stripped copper wire in your tank and run it before the peroxide goes bunk. That way you'll have a gallon of CuCl2 overnight, rather than a gallon of over diluted Muriatic acid.
handsome22 years ago
Wow! Just... Wow!
blanchae2 years ago
Very nicely done, well thought out and organized. Kudos to you. Have you thought of using a screw terminal strip for your connections instead of the twist on marrets?
crreed (author)  blanchae2 years ago
It would just take up more space; however, it would be a pretty good idea for the connection for the heater as you can see it is attached to the tank and disassembly would be much easier if that wire could come off completely.
f5mando2 years ago
That is wicked awesome! Kudos to you, sir.
pfred22 years ago
Pro job! This is indeed how the big boys do it. I think I'm going to rate you a 5. As this is about as good as it gets. In practice I found bubbling (air entrancing) my bath pretty effective so that is as far as I ever went. Was stupid easy to do too.
crreed (author)  pfred22 years ago
Thanks a lot. Etching with a bubbler is still a great way to etch but anyone making more than a few boards at a time can see how annoying that can get.
pfred2 crreed2 years ago
I would imagine. I only make boards one at a time just like how I put my pants on, one leg at a time. But after that I make gold records. I got a fever, and the only cure is more cowbell!
I would never need such a high volume device for myself but I envy your achievement. I think Instructables really needs a new kind of category for Ibles that really raise the bar as yours has. Thanks for sharing and making everything so detailed.
randofo2 years ago
Awesome project. You should enter this into The Make It Real Challenge.