Make Your Own PCB
  1. Making Your Own Printed Circuit Board - An Overview, part 1
  2. Making Your Own Printed Circuit Board - An Overview, part 2

Making Your Own Printed Circuit Board – An Overview, part 1

PCB Image Transfer

If you start tinkering with electronics, eventually you will want to make your own printed circuit board, or PCB as it is generally called. In the olden days, this subject was pretty straightforward. You went down to your local RadioShack, and bought an etching kit. You drew your single sided design using a marking pen and some supplied stickers. The board was fairly big, and it had only a few simple through-hole components.

Those days are now pretty much gone. Now most electronic projects are much more complex, the boards are much smaller, and you need to deal with 2 layers, surface mount components and vias. In this overview, I will tackle the different problems you may encounter and the methods available. I won’t cover PCB layout software or commercially made boards. I’ll deal with those topics in separate articles.

Basic Steps

Making a PCB involves several steps. Today’s PCBs require a lot more steps than they used to, but for your own use, these later amenities can be omitted. The steps involved are:

  1. Imaging your design onto a blank PCB
  2. Etching
  3. Drilling
  4. Amenities – solder mask, silk screen, tin plating
  5. Vias
Each of the steps can be fairly involved and each has its own set of problems. I will cover each one in detail.

Imaging Methods

As I mentioned before, simple circuits can be drawn with a sharpie marker, but these days, you will need to print out something called a mask using CAD software. There are several ways to transferring this mask to your blank PCB. Commercially, this process is done using a photo transfer process, which is also one of the ways available to you at home. The point of this process is to add a coating to your PCB in the shape of your circuit. This coating will permit the copper to be etched away from the blank board everywhere except where you want it. The coating that prevents parts of the board from being etched is called a mask. Because of the fine pitch features often required, this step is not as easy as it would seem.

Photo Transfer

Photo transfer is the most accurate way to image your design and is used commercially. It will easily provide the fine pitches needed for modern designs. It is also the most expensive method for home use. You must buy specially photo-sensitive coated boards and print your image onto clear plastic sheets. After printing the negative of your design, you lay it on your PCB and expose it to ultra-violet light to develop the coating which now becomes your mask.

Because of the extra expense and special boards required, I have never used this method. If you need fine features, using a commercial PCB service is really the way to go. If you would like to know more here are a few articles that describe the process:

Fritzing’s DIY PCB Tutorial

Lada Ada’s PCB Tutorial

Toner Transfer

The toner transfer method involves printing out a positive image of your circuit using a laser printer, and then using heat to transfer that image to your board. The pros including being quick, cheap and produces fairly good results. It is the method I prefer to use. The downside is that it is a little tricky to get good results and you often have some areas that need touching up with a sharpie. It can handle fairly fine features, but is definitely limited as compared to the photo transfer method.

Toner transfer uses the same basic process as the laser printer does. When a laser printer prints, it deposits the toner particles onto your paper and uses heat to fuse them to the paper. When you want to transfer this image to your PCB, you again use heat to lift the toner particles and fuse them to your board.

There are two ways to make the transfer – using an iron (like you iron clothes with) or a laminate machine. I have found the iron works well enough for occasional use. If you start making a lot of PCBs, then you should invest in a laminate machine. This company sells a laminator specifically for PCBs. You can also buy a cheap laminator from amazon for $35 and modify it as specified in this article.

The main problem encountered with this process is getting all the toner off the paper and onto the PCB. The type of paper you print on is the most critical part of the process. There are several resources available for buying (here or here)or making this paper. It seems to me that buying or making special transfer paper would be just as involved as photo imaging. If I were to need to make that many PCBs, I would go with the latter route instead.

For the quick, occasional home PCB, there is a surprisingly simple and cheap alternative to special papers – glossy, magazine pages. To use them, just tear out a page that is light on the printing and print your PCB onto it. The existing printing doesn’t transfer, so it is not a problem (the lightly printed pages are needed for YOU to see your design). The toner tends to not stick very well to the glossy pages which makes it ideal for toner transfer.

For more details, I have not found a better article on the subject than this one.

One last detail on this method involves registering double-sided boards. The problem is that the mask on both sides of the board much align with each other. The easiest way to do this is to hold the two masks up to the light (using thin magazine paper here helps) and aligning them together. Once aligned, tape them together. Then slip the board in between them and transfer using an iron or laminator. This article describes the technique in perfect detail.

While I was writing this article, a new how-to article appeared that uses parchment paper from the grocery store for the toner transfer paper. It sounds like a winner to me – I will be trying it on my next board.

Direct Printing

A third way to get your design onto a board is to print directly onto the board. This method sounds like the ideal one for home use, but it is not quite mainstream yet. The basic method uses a modified ink-jet printer. This website gives a lot of useful information on how to do it. There is also an instructable on doing it.

An alternative to etching PCBs also exists with ink jet printing – skip the copper clad board altogether, and print conductive traces directly onto a substrate. A new conductive ink that is a true solution as opposed to particles in suspension has now been developed making it ideal for this method. If you want to experiment yourself with either of this techniques, you should head over and join the yahoo group dedicated to making PCBs with inkjets.

Milling

The last way to transfer your design to a board actually eliminates the next step as well – direct milling of the copper using a CNC machine. While formerly the only available to wealthy corporations, with the advent of cheap 3D printers and DIY CNC machines, this method is now cheap enough to be available to everyone.

You can check out some of these popular designs and kits (here and here) if you want to explore more. I don’t have a desktop CNC machine myself yet, but I plan to get one eventually. When I do, direct milling PCBs will be my preferred method.

Etching Methods

Etching is fairly simple in its most basic form – you immerse the copper clad board into an etchant solution, agitate some and when you see the exposed copper dissolved, you remove the board and rinse. As with most things worth doing, there are many techniques to try to obtain a faster, better etch. The basic principles involved are temperature and agitation. The etchant needs to be warm and flowing across the copper. If it isn’t, the etching takes a long time and is more uneven.

There are two great tank construction articles I have found for making a really good etching tank. The first describes a thin vertical tank using an airstone for agitation. It looks simple and inexpensive. The second describes a spray technique that is really effective. While the build is more involved, it seems like a really great way to do it.

For the quick and dirty method that saves etching solution, I use the sponge technique. While wearing rubber gloves, rub the etchant solution onto the board with a sponge. It takes a bit of labor, but works quickly and well.

After you have successfully etched your board, you must remove your mask. The best way to do this is to use fingernail polish remover. The toner or photo resist comes off easily with a little bit of rubbing.

Etching Solutions

The traditional etching solution is Ferric Chloride. It is available from most electronics suppliers. For many people, they do not like working with this chemical. Apart from its ability to stain, I don’t have much problem with it. While I wouldn’t want to touch it, it doesn’t burn or emit noxious fumes.

There are some who favor using Cupric Chloride which begins as a mixture of hydrogen peroxide and hydrochloric acid. The raw ingredients are cheap and readily available. Hydrochloric acid is available where pool supplies are sold under the name muriatic acid. I don’t know if this solution is any safer than the traditional one, but I like the fact that the ingredients can often be found either at home or in a nearby store. Here is a great article on the subject if you want to learn more.

Coming Next

You are now armed with the knowledge necessary to successfully image and etch your PCBs. In part two of this article, we will explore the other steps to making a working PCB as well as some extra features common on commercial boards.

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15 Comments

  1. Posted May 14, 2012 at 5:32 pm | Permalink

    Thank for your kind information!This is really a help post for me to make it my own circuit design.

    • Posted August 9, 2014 at 4:47 am | Permalink

      There’s something also called “light Box” that you can print your PCB board during 10 min. only . you can use it in Alexandria ,Egypt and being active with us :) WELCOME ANYTIME :) ;) .

  2. Kent
    Posted June 1, 2012 at 1:30 pm | Permalink

    I’ve found that “transparency sheets” used for laser printing overhead projector slides worked VERY well for the toner transfer when using an iron. It required very little if any touch up. The sheets are a bit hard to find though (I found some at a local Fry’s).

    I now have access to a PCB mill and I have been experimenting with it. I would guess that for certain pitch sizes (around QFP for instance), I might have a hard time with the 0.5mm end mills I am using and might resort back to toner transfer.

  3. Posted June 1, 2012 at 1:34 pm | Permalink

    You’ve gathered some fine information here pal. Congrats’!

    Moving on to Part 2 and I’m loving it!

    By the way … isn’t electrolytic etching a solution ?

  4. Mike O'Dell
    Posted June 2, 2012 at 10:20 am | Permalink

    The etch performance of Ferric Cloride can be significantly improved easily – add some citric acid.

    the following is an article describing it – the good bits are toward the end

    http://www.polymetaal.nl/beguin/mape/edinburgh_etch.htm

  5. Joseph
    Posted June 2, 2012 at 5:58 pm | Permalink

    For etching solution I’ve had good results using the vinegar/hydrogen peroxide/salt combination (instead of ferric or cupric chloride) and a artist’s paint brush to periodically wipe off the accumulated gunk. Works surprisingly well with small boards and traces down to 12 mil.

    • Posted June 3, 2012 at 10:09 pm | Permalink

      Will you please share more details – amounts of each, what concentration of hydrogen peroxide, etc.?

      • Posted August 8, 2012 at 6:07 am | Permalink

        Hi Scott ok i have been etching for a very long time.

        1 part of hydroclhoric acid 36% PURE
        2 parts of hydrogeon peroxide. 4-6% CONCENTRATION.
        mix both first then pour in container with pcb.
        BINGO…….. FAST ETCHING PLUS HIGH QUALITY PCB.
        CLEAN WITH AND BAKING POWDER AND DONE.

        ENJOY very easy and you will be happy.

    • Posted June 26, 2012 at 11:34 pm | Permalink

      I’m also curious as to the ratios, and any further tips. Does it work better warm?

      • Posted August 8, 2012 at 6:13 am | Permalink

        hi matt,

        1 part hydrochloric acid 36 %
        2 parts hydrogen peroxide 4-6%
        mix together and add in container with PCB.
        wash PCB with baking powder and done.
        keep green solution in glass bottle.
        when you want to use again just shake bottle and then add a little hydrochloric acid and hydrogen peroxide. in container with PCB.

        This will last for a long time and is very cheap but very professionally no doubt.

        I have made 100s of PCB very high standard and sold quickly.

      • Posted August 8, 2012 at 6:20 am | Permalink

        The process i have explained is the best . You don’t need company’s to make your PCB .

        Over many years I tried all sorts of process but the one mentioned earlier is the best!

        Reusable and cheap. ( The green solution culpric can be used again just shake so this adds oxygen then a add simple parts of 0.5 hydrochloric acid and0.5 hydrogen…the magic will work!!!!!!!!!!
        once finished etching use solution again and follow process of shaking and adding.

        No doubt very professional finish that you can then tin your PCB for very good coherent track transition flow of electrons.

  6. Jeremiah
    Posted July 2, 2012 at 10:57 am | Permalink

    I used to do this a lot until my eyesight started to go. Now I just order my pcbs. Use a company called http://www.pcb-solutions.com fairly often, they seem really good.

  7. Posted August 20, 2012 at 10:48 am | Permalink

    What software do you recommend for use on your home PC? I imagined it would be a specialist piece of software for PCB design.

    • Posted August 28, 2012 at 2:28 am | Permalink

      I recommend either DipTrace or KiCad. I wrote an overview in this article. I currently use DipTrace. It is a Windows application, but is also well behaved under Linux via Wine.

  8. Posted April 4, 2013 at 10:59 pm | Permalink

    this is very useful for novice

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