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.
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Signing UpStep 1: Materials and Tools
To make things easier, I made the part list into a PDF. Do not let the long list intimidate you. A lot of the parts you may have lying around or may not need if you choose to leave out features. I have included everything I am using to give the broadest possible list. Keep in mind you may not want to go as crazy as I did with the features. I included what materials you will need on each step so you can pick and chose which you would like to use as easily as possible. You can obtain all the parts for about $300 completely new with the RV pump being the most costly (at $100) with the majority of the parts coming from Home Depot. You can also, like I did, repurpose acrylic or other plastic from anything you can thing of to reduce the cost even greater. The only clear sheet you need is the front and everything else could be solid if you want or you could even use a mix of acrylic, MDF, and PVC liner to create you own custom tank. Again, this is the part list I used so do not let that limit you in your building. Message me if you have trouble finding/understanding anything I included on the list and I will be happy to help.
Also, I have included all the Sketchup plans, diagrams and other resources in the Zip file here (if its easier to download them all at once) as well on each step.
Materials
See attached PDF
Diagrams
See attached zip file (collection of all the files for the entire Instructable, although they will be found again on each of their respective steps)
Tools
- Drill with assortment of drill bits
- Spring Clamp
- Rotary Tool
- Circular saw (with fine tooth blade for cutting acrylic; radial arm saw also will work)
- Exacto Knife
- Screw Drivers (flat and phillips)
- Soldering Iron
- Heat Gun
- Dremel Multimax (optional)
- Corner clamp (optional)
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Brilliant design, love it to bits.
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?
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.
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.
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!
http://members.optusnet.com.au/eseychell/PCB/etching_CuCl/index.html
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.