How to Make a Professional Printed Circuit Board: the Complete Guide

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About: I'm french, I'm a first-year student at INSA Rouen-Normandie school of engineering. I love technologies (Arduino, 3D print...) and DIY projects. I practice electronic since I am 12

Intro: How to Make a Professional Printed Circuit Board: the Complete Guide

Hello everybody, today I will show you how to make professional PCB, to improve your electronic projects.
Let's start !

Step 1: What You Need to Buy

Exposure box

Presensibilized epoxy

Tin solution (optional but recommended)

NaOH (sodium hydroxide)

FeCl3

Acetone (you can find it in a supermarket)

( Here is the link to the project related to the PCB you will see in this tutorial : Computer Control Box )

Step 2: Drawing the PCB

If you already have the design of your PCB in a file, you can skip this step

I am using Proteus software to draw my PCBs, but you can also use Fritzing software to do that. The most important is that you can export your design into a .pdf file. PDF keeps real size so if you print this file to a 1:1 scale, you will not have scale troubles after printing.

Step 3: Printing the Artwork

Now print the PCB design on transparent sheets
I advise you to print a least 3 copies of the artwork, you will get better results because the opacity will be better at the exposing step...

Step 4: Setting Up Chemicals

During these steps, wear gloves and work in a well ventilated area and wear a pair of goggles. You will handle strong bases and acids. Some of them evaporate easily in the air. I also advise you to wear a lab coat or old clothes because an iron chloride spot can not be cleaned. It lets a disgusting yellow-brown color ...

/!\ Never pour liquids containing metals into the environment /! \ Use a bottle of chemical waste that you can give to a waste disposal site.


Prepare a bath of relelator for prepositive sensibilized epoxy. It is just sodium hydroxyde ( concentration 15g/L ) Let it to the room temperature.

Prepare an other bath with a solution of iron III chloride (FeCl3)
If you want the reaction to go faster, you will need to catalyse the reaction between the acid (FeCl3) and copper of the PCB, it means you will need to heat the iron III chloride solution. To do that, I use a hot water bath (see pictures) Without this, the result will not be as expected.

Heat the water in a boiler to a temperature of about 80 ° C, once it is hot pour the water into a larger container than the FeCl3 one. Place the FeCl3 bath in the hot water bath.

Also prepare a water bath, (distilled water is better) to wash the PCB between each steps. It is also a good idea to keep absorbing paper next to you... When you wash the PCB, absorbe water on it to not dilute the next bath.

Step 5: Exposing the PCB

Let's set up the UV-light exposure box.

Take the first artwork and attach it to the pane with adhesive tape. (Be careful about the orientation of the artwork !)

Then add the second and the third design onto the first one to improve the opacity. This trick will prevent UV rays to cross black lines of the design.

Now you are ready. You will work with photosensitive resin, so you will have to work in a place where the brightness is reduced until the PCB is not developed.

Ready to start ? Go!

Carefully remove the protective film of the PCB. Place the sensitive side into the design and secure it in place with tape. Put all of this into the exposure box, sensitive side facing the UV tubes and close the box.

Turn it on between 2' to 2'30" no more. During this, put gloves and goggles to protect yourself from chemicals. Once time is over, switch off the exposure box, open it and take the PCB.

Step 6: Developing the PCB

Place it immediately into the sodium hydroxide bath, sensitive face up. You should immediately see a blue-purple color (sometimes grey) going into the sodium hydroxide. Slowly shake the bath until you great see the design. (Around 30" - 60")

Wash the PCB into the water bath.

Step 7: Engraving the PCB

At this step, the PCB is not photosensitive at all, you can switch on the light !

Now place the PCB copper-face up into the acid bath (FeCl3) and slowly shake it back and forward. The solution always need to move to the reaction take place. (About 20' to 40' depending on the water bath temperature, the surface area of copper to disolve and the concentration of the FeCl3 solution.)

When all copper have been dissolved by the acid, remove the PCB and wash it into an other water bath and dry it out.

Step 8: Washing the PCB

Now you need to remove the remaining resin on the circuit. To do that, place the PBC into an acetone bath. Acetone will become purple. (Around 10" - 20") The copper is henceforth exposed.

Then wash the PCB into water, and you are done !

Step 9: Tinning the PCB

It's an optional step but I advertise you to do it because it will help you to solder components and prevent corrosion.

Place the PCB in a empty bath and pour a little bit of tin II chloride solution on it. It will lay down tin on the circuit.

*** Success ! *** You made a professional PCB !

Step 10: Drilling the PCB

Use a vertical drill and a 0.8mm drill bit to drill every holes, and if the pin of the component is too large to go through, use a 1.2mm drill bit to enlarge the first hole. ( Always start with the smaller drill bit you have, to drill a precise hole ! It is very important ! )

And your PCB is done ! The only remaining thing is to solder your components on it !

I hope you like this tutorial

If you have any question, leave a comment ! ;)

( Here is the link to the project related to the PCB you saw in this tutorial : Computer Control Box )

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    33 Discussions

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    preschau

    9 months ago

    I found that sodium metasilicate (brewers detergent) works well as a developer, it's not as dangerous or corrosive as the caustic soda mentioned above.

    I use about 50gms to a litre of water and this will develop a board in a couple of minutes.

    To remove the photoresist after etching, methylated spirit (denatured alcohol) works well and is cheaper and easier to obtain than acetone.

    Sodium Metasilicate.jpg
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    ram713

    1 year ago

    Good refresher as I did this 20 yrs ago. Many refs use symbols that represent feet and inches ( ' and ") and don't make much sense.... the reaction take place. (About 20' to 40' depending on the water bath temperature, .... Acetone will become purple. (Around 10" - 20")

    2 replies
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    poloniusram713

    Reply 1 year ago

    I think you are getting symbols confused. In this context these symbols are used for measuring time, ' being minutes (About 20 to 40 minutes...) and '' seconds (Around 10 to 20 seconds).

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    eqwipmanpolonius

    Reply 12 months ago

    Thanks I needed that. I was confused.

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    Orngrimm

    1 year ago

    If downloaded as PDF, the step 1 is incomplete...

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    Kolynskij

    1 year ago

    I made these boards for quite a few years. The example you show is under-exposed, give it a few seconds longer in the UV box. Make sure your glass is clean. Longer UV will crisp up the edges, and define the gaps.

    Under-exposing usually means you over-etch to compensate, and you lose definition.

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    AngeloBrito

    1 year ago

    Very interesting process, it is similar to the Photo Paper + Laser Printer + Clothes Iron + FeCl3. This one, which I had to use on university, is cheaper but the finishing is horrible. Though, if you have access to a maker space you can also use a laser cutter machine to engrave on a black painted copper board and corrode the copper.

    Which one to do you think would have a better cost vs finishing?

    And nice work!

    3 replies
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    ClaudiohaseAngeloBrito

    Reply 1 year ago

    You can use magazine paper, is better than photo paper ! It is lightly waxed paper, and laser printer ink takes off more easily. I have used for a long time !

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    JoebarteamAngeloBrito

    Reply 1 year ago

    If you have access to a Maker Space with the appropriate equipment (CNC machines...) it must be cheaper and the result may be better than the method I described here. But if like me you love making everything by yourself, this method is a very good one. ;)

    Thank you

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    Liamthe1st

    1 year ago

    Let's keep it Simple can these chemicals be bought over the counter in all countries ?

    1 reply
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    JoebarteamLiamthe1st

    Reply 1 year ago

    I don't know but I do not think factories use this process...

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    Usually Baffled

    1 year ago

    Can you describe how to achieve plated through holes (vias), which would be the remaining step to professional boards? Actually, multilayer boards would be closer to professional for advanced products like fast analog to digital converters and some other kinds of jobs like complex digital circuits but beyond 2 sides probably should be left to profesional manufacturers.

    4 replies
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    Usually Baffledsyevtushenko

    Reply 1 year ago

    Hello!

    Thanks for telling us all about this. It is a very valuable contribution to home electronics fans. I wish I knew about it decades ago!

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    BernhardS15Usually Baffled

    Reply 1 year ago

    Producing plated through-hole vias is hard to do. In PCB production, they start with drilling the board first, then a galvanic process is used to get copper into the holes. After that, ohtorestit ist applied and dried. Then you need a double-sided light-exposure box and 2 films thar are perfectly aligned....

    Usually, if you want double-sided, try to get the vias into the pins of your parts (resistors work best), etch both sides, drill, and solder your parts top and bottom. Free vias have to be soldered on both sides (tip: after soldering one side, don't cut too much of the wire you use as a contact. When cut too short, you risk pulling out the wire when you solder the other side - and you don't see this at a glance!)

    Best way to get professional double-sided PCBs is to have them produced in China. You get 5 or 10 pcs of 100x100mm double sided boards, best quality with solder mask and silk print for less than 10$. Only drawback, if you need larger boards, prices go up sharply.

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    RubenP51BernhardS15

    Reply 1 year ago

    Yes, I used to buy extra thin single sided boards, dril 2 holes in both layers, align them with pins and the glue them together with expoxy glue. There are also rivets for sale that can be used for the vias. Lot of work and not always very reliable.

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    Bogey123

    1 year ago

    I used ammonium persulphate solution - cheap, relatively harmless, makes a clear solution so your work progress is easy to see - takes a little longer, but safety is the big thing.

    1 reply
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    syevtushenkoBogey123

    Reply 1 year ago

    This solution is one of the worst for the thin processes like 0.15/0.15 track/space. It's quite painful to make it etch more or less uniformly. Note that this low uniformity is an inherent property of this solution and does not depend on physical conditions of etching process.