If you have ever produced your own PCBs at home, you know that it can be somewhat of a time consuming process. Spending 20 or so minutes manually agitating a board is a drag, and while aquarium bubbler setups improve the process, they are far from ideal. [Christian Reed] knew that if he really wanted to streamline his PCB production he had to emulate the big boys and build a PCB sprayer of his own.
His spray etcher is contained in a custom acrylic case built mostly of scraps from previous projects. It contains two compartments – one for spraying etchant on the PCBs, and another for rinsing the finished work. The system is impressive to say the least, featuring a maze of tubes and piping which allow him to etch boards and manage his chemicals with ease.
[Christian] says that although the parts list might seem daunting at first, it really is pretty easy to assemble the device. Seeing as he can etch and wash a board in about two minutes flat, we think that any amount of effort would be worth the results.
[Christian] points out that he was unable to find a guide for building this type of PCB sprayer anywhere online, so he documented the process in painstaking detail in order to make it as easy as possible to replicate his work. Be sure to check out the video below to see his etch tank in action – we’re pretty sure it will have you itching to build one this weekend.
[youtube=http://www.youtube.com/watch?v=BaSWDJBhp-0&feature=player_embedded&w=470]
that is nifty.
mine is a regular vertical diy etching thingy, with bubbles coming from the bottom, it’s pretty fast, as in ~2minutes… far from those 20 minutes you’re talking about…
Make something slot-loaded that can etch+bake surface mount, and you’ll probably be like a god in this community..especially if you implement stenciling so people can do BGA stuff..
Now this could be useful. Next up, doing a CPU on the desk.
This would be usefull if it didnt take like 10 minutes to setup before and after heh.. still about a 20 minute process… I etch pcbs by hand and got it down to 10-15 minutes…
I imagine it’s pretty quick by comparison when you have to do a lot of boards at once.
I like the idea of keep etchant in those gasoline-type containers.
I use the sponge wipe technique… and it’s super fast. 2 minutes or less to do a single sided PCB.
last time I did the sponge process I watched in horror as the toner wiped off and scurried for a sharpie.
done it before no problem, wasnt using any pressure but oops there it goes half way though and some fun words were said
It looks like a lot of work to run the machine. Why not use a cheap ultrasonic cleaner from harbor freight and add a heating element? Bet that would be faster.
Nice!! Fun to hear how many methods people use to etch a board. One guy told me he uses old record player to do etching. Round container on top of turntable, and set it rolling. Don’t remember if he tilted the whole thing so board gets ‘dipped’ in every round.
A simpler setup:
DIY a “stir plate”, an orbiting magnet device used in chemistry, biology, and of course homebrewing.
A stir bar is made of iron dipped in inert food grade plastic. It should withstand acids. The stir bar will constantly agitate via the whirlpool effect. Use a glass casserole dish, preferrably one which takes a plastic lid.
You can build a stir plate from a 9v to 10v power supply, a computer case fan, and some magnets from a hard drive (glued to the fan). Cost $0. I built one of these and it’s great for propogating liquid yeast packs.
I’d be carfull with mists of etching fluid, it wrecks you lungs..Tired nitrogen solder cleaner once, it was not a nice experience..
All it does it make it etch faster. I mean, really great job on the build…. I am impressed. And I can understand getting obsessed with an idea and going for it as I’m often so infected myself.. but any of many hand agitation methods and…. I mean… I admire the work done and that it works great… but eww! Ick! Gimme bubbles or agitation or just let it lie WORKS FINE. This is in the category of a method that “ain’t broke, don’t fix it.” Still… he did nice work! Gotta have a big payback for me to take on a project this size. I don’t see it. Must be he’s doing tons of boards, then I could see it.
I etch in a water bath to keep the temperature of the ferric chloride solution high. 20 minutes would be an overkill, 10 it what it takes at most.
Hey all,
This project was designed for labs not looking to spend a ton of money on professional sprayer but still needed to make PCB’s in batches of 20 or more which a lot of labs at my college do. This justifies the long setup time and allows one to rapidly etch a lot of boards. Hope this clears up the confusion.
-Christian
Hello Christian,
This is great work, I can see you’ve got a rage to master.
I can relate to the point you made about the lab : I’m in electronics and to etch a board, the guy in the lab told me he had to do them in a batch. And it took too long.
For this year, I have to do a project involving microcontrollers and sensors (mandatory).. So I thought of striking two birds with one stone: Doing the project and providing the faculty lab with a little instrument to make things easier for me and for the coming promotions of students.
I thought of an etching tank with a controlled temperature heater (different etchants –>different optimal temperatures..) and a display, and then thought about it and figured out that since it is a surface treatment, spraying would be more efficient (since there is a phenomenon of saturation, yes it can be decreased by the bubbles in the tank .. But still, spraying should be more efficient..) And searched and found some posts in fora, etc .. And now this.
I’m still hesitating between the regular tank+heater+bubbles and the spraying method, due to time constraints and the fact I’d like to present a good (near perfect) product.
Again, this was very good work.
All my best.
~Jugurtha Hadjar,
Twenty minutes!? What kind of process are you using? I etched a board just a few hours ago and it was done in under two minutes. Granted, it was a small board but still, I’ve never ever spent twenty minutes agitating a board, not even big two sided ones.
you should really find a way to mass produce this and sell it. I would buy it in a heartbeat! or a tutorial of how you build this would be nice as well
http://www.instructables.com/id/Printed-Circuit-Board-PCB-Sprayer-Machine/
I now have a use for that old fish tank in my garage. I know what I’m doing tomorrow.
just etched a board by hand (sponge) with FeCL – did it in a cold garage on a cloudy dull morning. Wondered why it took so much longer than ppl told me it should.
Oh yeah – cold etchant >.<
Something like this machine would be a godsend.
Yeah, you really shouldn’t etch on cloudy dull mornings 😉
I suggested in another post, just build a stir plate. You can build a little heater into one (just use a 12v automotive reverse light in the case.. it’ll heat things up).
Nice project. Obviously, a lot of thought went into this. One point of criticism…
I’m bothered by the direct water connection to this machine. In order to avoid the potential for backwash/back-siphon, at the minimum, the water feed line should contain a check valve and a vacuum breaker.
An even safer design would include an additional fresh water reservoir that is filled from the top with a drop tube or spigot. The reservoir would then feed the rest of the machine.
I see no way that any of the acid solution could be pushed by the ::suction:: side of the pump, back into a pressurized feed line. Sorry, just not gonna happen.
Apparently you’ve never heard of the word “siphon.”
Talk to guy who installs swimming pools. Ask him what code requires with regard to water-fillers.
ya, just did a dairy course… there all over this… they can imagine the impossible
Very nice! I am going to attempt one of these as it should preform at least better than the non-aerated pan I am using now. I like the idea of everything being contained.
I am also going to implement a “neutralizer” tank to dose a small amount of high-ph solution to bring any remaining acid to a safer ph. if one were to do that with a copper chloride type etchant, you could drain to the sewer without worrying about your plumbing or the environment. (by that I mean the <25ml remaining in the tank)
There is no need for a neutralizer tank in a build that uses non-harmful materials such as muriatic (hydrochloric) acid. The approved disposal method is just to rinse down the drain with plenty of water, it is not an inherently harmful substance, and occurs naturally in nature (your stomach).
Copper itself however is not approved to be rinsed down the drain as it is a heavy metal. You would need to first remove the copper by electroplating it onto some sacrificial cathode or otherwise precipitating the copper from the mix.
Yes, but hydrochloric acid will readily eat up your copper pluming. Much quicker when mixed with an oxidizer, after all, copper is what is being dissolved here in the first place 🙂 The water method on the muriatic acid bottle implies you are using it to clean outdoors as also advised.
The best part about the HCL + H2O2 etchant is it gets better as you use it . I have been using the same 750ml for the past 6 months, just keeping it aerated and a dash more 30% H2O2. even then, it still reacts with the neautralizer I use in the pan. I would not want to put that into the groundwater as-is. After the HCL is taken care of it’s good to go as the copper contained is naturally occurring and relatively harmless.
Cool build. But honest question: How is any kind of chemical etching approach (this one included) better than “etching” with a CNC mill?
Correct me if I am wrong but you cannot do 10mil traces with CNC mill, this is business as usual with photo resist PCBs. Also CNC is quite slow if board is complex. I once bought MAXNC CNC mill for ‘etching’, but now use it only for drilling holes. heat transfer/photo resist is the way to go.
Even if you could do thin traces with a clonky tooling, the space between traces would still be too big. Not to mention pads that are even closer together.
CNC is best for drilling, routing, and v-carving. Chemical process is best for traces; Smaller tolerances, a lot faster, and less expensive.
I can certainly see it being rather useful for batches.
The timer is a neat addition.
The only thing I couldn’t really tell was how it was spraying.
If it was spraying from the side with the etchant lines, surely it would result in uneven coverage if you’re doing batches spread across mulitple frames?
Nice attempt, am a hobby guy and currently using Dual jet etching machine from Etchcut, India but it does not have washing tank and i normally do double side etching , I think i can try that to make my own washing tank from your project, am in australia and really find it difficult to find photoresist liquid does any one know any source, am currently buying this from India only