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I have finally built up a lab to design electronics in. I have quite a few designs I would like to test. I have tried the printer toner/iron technique a few times but have found that I cannot create small pitch sizes as they tear off while removing the printer paper. A few people have mentioned that this is due to using a Samsung laserjet versus a HP.

I am wondering what methods you use to develop PCBs for one-offs in your lab or at home (like me). I am trying to fast track a move to SMT/SMD components and would like some tips from seasoned experts on the best PCB creation methods to test board concepts before sending them off to a PCB MFG. I would like something that balances cost, time, and beauty of the finished product geared towards a hobbyist (at this point) and geared towards SMT/SMD components.

Please include pics/documentation of your preferred method. Thank you in advance for your post.

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    \$\begingroup\$ As this was just flagged as a duplicate of a just closed question: I have just uploaded a 30 page group discussion on the toner transfer method to this dropbox file). Have a read through there and come back and ask relevant questions if it seems to be of use. \$\endgroup\$
    – Russell McMahon
    Aug 5, 2011 at 13:22
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    \$\begingroup\$ @Russell - 30 pages is a lot, and I guess it will have some noise in it too. Can't you just post the gist of it here? \$\endgroup\$
    – stevenvh
    Aug 5, 2011 at 14:18
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    \$\begingroup\$ Much noise. Conversational style. Treasure for some, dross for others. Someone using their brain can subset it in moments compared to the time it would take me for unknown benefit. I went so far as to use GMail to concatenate the thread and made a Word document from it and posted it in dropbox. In the time it took me to do that the question had been closed. I have built it. If they care they will come :-). If not then that's fine. \$\endgroup\$
    – Russell McMahon
    Aug 5, 2011 at 14:25
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    \$\begingroup\$ @EzekielVictor Do you expect an old dog like me to still have a file from almost 13 years ago ? :-). WELL here it is :-) - duplicated = dropbox.com/scl/fi/3f74qfetl6jp539anhauh/… - 28 pages \$\endgroup\$
    – Russell McMahon
    Mar 30 at 4:45
  • 1
    \$\begingroup\$ Look at you! ūüĎĆūüŹĽ \$\endgroup\$ May 8 at 4:43

9 Answers 9

76
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For one-offs or prototypes I use:

  • Press-n-Peel transfer film with a laser printer (the blue one)
  • Steel wool and detergent to clean the PCB blank, then a short etch in ammonium persulphate: that gives a very clean surface, important for a good transfer from the film
  • A laminator to transfer the pattern to the PCB; I modified the laminator to raise its operating temperature a bit, and the PCB is a bit thick for the laminator but it works
  • Ammonium persulphate made with hot water in an ice-cream container, and that sits in a bath of hot water (a larger ice-cream container)

This gives good results down to 10 mil trace widths; could probably go finer but haven't needed to yet.

For double-sided boards I tape the two layers of Press-n-Peel film to two scraps of PCB at the edges so that I can get the two layers well aligned, then put the PCB blank in and feed it through the laminator. Here are some pictures to illustrate:

alt text The bottom (left) and top (right) of a simple double-sided board (the top one is printed out mirrored so they overlay when its turned over). Normally I would print onto the blue Press-n-Peel film, just using paper here for illustration.

alt text With one side taped to the scrap PCB (left side) and the printed sides facing each other, hold them up to the light and align the other one so that all the holes and the board outline line up.

alt text Here they are both stuck to the PCB scrap. You can now put the clean blank PCB between the two (probably best to tape it to both sides to avoid any movement) and run it through the laminator (or iron it) to transfer the toner onto the PCB.

You can tape the two pieces of film or paper together without using the scrap of PCB, but when you put the blank PCB between them you can get some relative movement as they flex around the thick PCB. With the scrap piece the same thickness as the blank PCB they stay in the right place.

A bench drill is good for any drilling. I use drills down to 0.5 mm diameter but with 3 mm shanks so they are easily held in the drill chuck.

For through holes I solder thin copper wire to the pads on either side. The wire comes from a multi-core flexible cable; individual strands are or about 0.2 mm or 8 mil diameter. This takes some time!

And to solder I place solder paste with a fine-tipped syringe, place parts with fine tweezers then reflow in an electric frying pan. A few more pictures:

alt text

Syringing solder paste onto SMD pads.

alt text

Placing component with tweezers

alt text

A finshed board - the PCB was professionally made but I assembled components and soldered as described here. These are 0402-size resistors and capacitors (quite small, amazingly easy to lose), an accelerometer in a QFN-16 package (4x4 mm) and a memory chip in an 8 pin leadless package, similar size to a SOIC-8. (This is part of a small accelerometer data logger, see vastmotion.com.au).

Good luck!

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    \$\begingroup\$ Could you describe in a bit more detail the method you use for double sided boards? Do you have pictures of your process or a link(s) you perfected your process from? Also I would be very interested in more details concerning the use of solder paste. Thx! \$\endgroup\$ Nov 22, 2010 at 9:29
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    \$\begingroup\$ Yes, that was a bit sketchy! I've added some pictures to illustrate the process. \$\endgroup\$ Nov 22, 2010 at 11:15
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    \$\begingroup\$ Excellent answer John. Hope this takes top spot. \$\endgroup\$ Nov 23, 2010 at 22:32
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    \$\begingroup\$ syringing solder paste is kind of slow. Your local hardware store probably has some sheets of 0.003" or 0.005" brass shim stock. If you etch it like a PCB you can make a stencil with it. Here's a picture of a stencil I made: imgur.com/UulSo (This one has been used on about a hundred boards.) more here: delorie.com/pcb/brass \$\endgroup\$
    – markrages
    Nov 24, 2010 at 3:24
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    \$\begingroup\$ What is "press-n-peel transfer film" called in stores? Googling finds lots of things called that, but none market themselves for PCB fabrication. \$\endgroup\$
    – Cerin
    Oct 30, 2015 at 22:13
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Unless you're on the tiniest of tiny budgets, just have the boards professionally fabbed.

Really, you can get such a good deal on PCBs, with suppliers like:

  • 33Each.com ‚ÄĒ 60 Square inches, double sided, 6/6 spacing. $33 ea, minimum order: 4 (1 if you have a university address)
  • GoldPhoenix ‚ÄĒ Good for bigger runs, cost varies depending on requirements.
  • ExpressPCB ‚ÄĒ 3 boards for $51 total, double sided, no soldermask or silk, rigid size requirement of 3.8 √ó 2.5
  • AP Circuits ‚ÄĒ No personal experience, see comments below.
  • Sunstone Circuits ‚ÄĒ As cheap as $28 for a prototype. Fast and good quality, I've never had a problem (From Garrett Fogerlie).
  • OSH Park ‚ÄĒ $5 Sq. In double-sided, $10 Sq. In, 4 layer. Boards come with purple(!) soldermask.

On the whole, I've found that (for me, at least), it's just completely not worth it to try and make my own boards, when I can buy a much nicer board or ~$50.

Also, with most professionally fabbed boards, you get all the niceties, like soldermask and silkscreen. Having a soldermask makes soldering small pitch components far easier, and the silk makes populating components much easier, particularly when boards get large.

How much is your time worth to you?


Edit: Removed BatchPCB from the list since they no longer exist (sold to OSH Park in 2013).

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    \$\begingroup\$ I can have a board ready for assembly in under an hour. At £30 an hour for my time, it's very cost-effective for me. I could get a nicer board made for that, but I'd have to wait a couple of weeks for it. \$\endgroup\$ Nov 20, 2010 at 13:02
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    \$\begingroup\$ Fake Name: I agree that you can get great results from a pcb mfg...however, I have to go with Leon on this one. If I get a wild hair up my ***, I want to be able to build it out in a few hours versus waiting 2+ days. If I am going to make a few of them, however, I am definitely sending the PCB to the MFG. \$\endgroup\$ Nov 20, 2010 at 17:28
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    \$\begingroup\$ @Leon Heller - Under an hour? Really? Including drilling? I guess your boards have fewer holes than almost all my projects. \$\endgroup\$ Nov 21, 2010 at 4:08
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    \$\begingroup\$ @Fake Name: SMT is the future. \$\endgroup\$ Nov 22, 2010 at 16:44
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    \$\begingroup\$ Anything that I could make that needs a single layer of copper I can do with veroboard and point-to-point wiring. Anything else I have sent out to either apcircuits.com (single/double layer, extremely fast turnaround) or sunstone.com (multilayer, larger boards, higher volume). It's not worth my time to try and etch my own boards, especially double-sided. \$\endgroup\$
    – akohlsmith
    Nov 24, 2010 at 14:12
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I get excellent results (down to 8/8 mil) using the photo-etch technique. I use a cheap HP 5940 inkjet printer with Mega Electronics JetStar Premium film for the transparencies with pre-coated positive resist boards, exposed in a home-made UV exposure unit. Boards are developed in sodium hydroxide solution and etched in ferric chloride in a small plastic container in an old washing-up bowl with about 1" of very hot water in it. The small container is agitated manually, and etching takes about 5 minutes. I can make a board in about 20 minutes, not including drilling.

Here is one of my boards.

This group is a very good resource for making PCBs at home.

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    \$\begingroup\$ So far I have used the Muriatic Acid + Hydrogen Peroxide method. How messy is the process you use? What kind of disposal is require? Thx for the link, I am going to take a look at that right now. \$\endgroup\$ Nov 20, 2010 at 17:31
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    \$\begingroup\$ Ferric chloride stains things badly. It lasts a very long time, and the life can be prolonged by adding hydrochloric acid. Small amounts used at home can be flushed down the lavatory, the copper content is minimal and ferric chloride is used by water companies. \$\endgroup\$ Nov 20, 2010 at 17:37
  • \$\begingroup\$ Good to know...Here in the states, I would hate to have the EPA knocking on my door. \$\endgroup\$ Nov 20, 2010 at 19:21
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I'm no seasoned expert but... I have learned from them.

I have the second cheapest Samsung mono printer available and I have no problems with fine traces; I doubt it is your printer.

I have had good success with laminators but someone recently told me this could be dangerous on cheaper models with improper shielding (as the board is highly conductive).

I have returned to ironing for double sided boards as it seems to be a tad more accurate. If you're not getting good transfers try using an electric sander with a very high grit rate to get it much cleaner than any abrasive brush can. Then, the most important thing to do when using an iron is to push hard, like really hard and hold it in place for at least 30s at a time. If you have normal glossy paper and can't see the traces, you're probably not ready to soak.

Another thing I have found to help is to have a 2mm or so border around the whole circuit. This then tends to stick first and helps prevent the paper from moving while you are ironing.

Currently my kit features the following items:

My new camera arrives today and I intend to launch a "website of journey" as I both learn and experiment with electronics. One of the first videos I will put out will be my PCB production process.

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    \$\begingroup\$ Interesting..I am running with the Samsung ML-2250. I have not replaced the toner in a few years. I'll try your suggestion plus replace that toner. I would be very interested in seeing your site/videos. Please leave a link in the comments when its up. Look forward to checking it out. \$\endgroup\$ Nov 20, 2010 at 17:23
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    \$\begingroup\$ I think the #1 problem anyone making their own boards has is that they don't actually start with CLEAN copper. Clean copper is pinkish, not copper-ish. Wash it down thoroughly and give it 15 seconds in an etchant bath, then wash it off immediately with distilled water. You'll notice the board is hot pink. This is clean copper. \$\endgroup\$
    – akohlsmith
    Nov 24, 2010 at 14:12
  • \$\begingroup\$ @ThaKidd: I added a new answer as it's related to this topic (too long for a comment). I haven't done the walkthrough yet - that'll be next hopefully. \$\endgroup\$ Nov 28, 2010 at 21:42
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    \$\begingroup\$ While there are many variables, I've had great results with cheap HP printers but terribly unusable outcomes with a comparable Brother and a large whole-office Canon, using the same procedures. So I think the printer/toner definitely is a factor. \$\endgroup\$ Jan 9, 2013 at 20:26
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    \$\begingroup\$ Stackoverflow seems to be breaking most of your links with some sort of sleazy tracking system. They're showing up as http://rads.stackoverflow.com/amzn/click/<id> and redirect to a 404 page even though your original links still work. \$\endgroup\$
    – Cerin
    Oct 30, 2015 at 22:43
5
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I have just finished creating a tutorial on how to build a Bubble Etch Tank (unheated), at home, with minimal cost and effort. Hopefully this will be helpful to someone:

  1. What You’ll Need
  2. Plumbing the Air System
  3. Making Bubbles
  4. The PCB Basket

I'd recommend increasing the resolution to 720p but of course, this is optional.

I'll be adding further updates (such as seeing the tank in action) at 13 Volts fairly soon.

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I would vote for cheap Chinese off-shore, too. iteadstudio.com can make 10 boards 50x50mm for $10, and 3-day air shipping for the order is < $30. Total turn-around time is a tad over a week. I hear that seeedstudio.com is very similar (and may actually be using the same PCB fab.) You get solder mask, silk screen, vias, plating, the shole shebang. The only draw-back is they can only do 1 oz copper thickness, and they aren't very precise at tiny pitches (8 mil is their minimum.)

For doing my own, I would recommend against the CNC mill route. Yes, it's nice that you can drill the same board you mill, but the milling generates glass dust that's really bad for your lungs, and it easily breaks the tiny bits you need, and the edge finish is kind-of ragged and not trustworthy for small pitches. Instead, I would go with UV-based photosensitive coated boards. Laser print the mask (inverse) on transparencies. Expose on a UV bed (can be built yourself if you really want to.) Develop. Etch.

Then, that CNC mill may still come in handy, for drilling the board :-) You're still not going to get through-hole plating, vias, etc, this way.

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    \$\begingroup\$ The only real justification for making your own is in the cases where the fact that you can design, fabricate, and test the circuit inside of a few hours of a single day is important to the progress of your overall project. Well, that and RF people and others who need exotics. \$\endgroup\$ Jan 9, 2013 at 20:29
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    \$\begingroup\$ pcbshopper.com is a great place to search and compare PCB manufacturers. (I am just a user, no other connection whatsoever). \$\endgroup\$ Jan 1, 2017 at 17:33
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Thanks to everyone so far for your answers. I believe I have made a decision concerning future circuit board design. I have been doing some crazy research and ran into a piece of equipment that I believe might be the best route. It is not only eco friendly but useful in many other ways. Props have to go to Brian for triggering the research that led to the epiphany.

Instead a dealing with chemicals which requires disposal, time, and is not ideal since I live in a condo, I have decided to build a CNC Mill. There are numerous tutorials out there and it appears one can be built for ~$500 (or less if salvaged parts are used). Here are a few links I have found so far.

Instructables

Engaget (1of3), (2of3), and (3of3)

The mill would not only serve the purpose of removing the copper but can also be used to build a solder mask. This would enable easier SMD/SMT manufacturing using the skillet reflow method.

I plan on doing further research to see if a 'combo' cnc machine can be put together which also takes advantage of the RepRap 3D plastic printer. Imagine the possibilities of this killer combo. You could fabricate almost anything and it should cost under $1000.

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    \$\begingroup\$ How do you plan on adding solder mask to the boards using the CNC? Are you buying pre-masked copper boards and effectively "sanding off" the soldermask for pads, then going a little deeper to remove soldermask and copper for traces? \$\endgroup\$
    – akohlsmith
    Nov 24, 2010 at 14:25
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    \$\begingroup\$ Unless you spend a lot of money, milling PCBs is very slow. \$\endgroup\$ Nov 24, 2010 at 15:33
  • \$\begingroup\$ @LeanHeller, @ThaKidd, We use cnc mills at my school as the simple process(also chemical etching). They are slow and the bits are expensive to replace. \$\endgroup\$
    – Kortuk
    Nov 25, 2010 at 17:24
  • \$\begingroup\$ In particular, reprap.org/wiki/Automated_Circuitry_Making shows a PCB that was milled by a RepRap. \$\endgroup\$
    – davidcary
    Mar 4, 2011 at 19:52
  • \$\begingroup\$ @ThaKidd please post a follow up about your experience with the CNC mill. I have a CNC mill, but have yet to mill a PCB as it seems pretty time consuming. Ad that to the fact that you can get a good proto for $100 in a few days or $20-30 in a week if you want to wait. \$\endgroup\$
    – BrianV
    May 5, 2012 at 16:50
2
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I wasn't getting reliable results ironing on toner transfer. I modded an old waffle iron - named the PCB Press. I like the ability to produce a prototype board at home in under an hour. If I need something of professional quality I send the tested proto out to fab house.

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  • \$\begingroup\$ Your link is dead. \$\endgroup\$ Mar 5, 2021 at 21:24
0
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As this was just flagged as a duplicate of a just closed question:

I have just uploaded a 30 page group discussion on the toner transfer method
to this dropbox file <-- FAR superior format compared to copied version below.

Have a read through there and come back and ask relevant questions if it seems to be of use.

I've posted the first 40% or so below to stop this being a link only answer.
For those interested in this method I strongly suggest you access the complete and better formated dropbox document. There is such a vast range of material from many people in this invaluable document that it's very worth looking at.

Edit: Link updated March 2024

-------------------------------------

From:¬†V G¬†[email protected] Date: 20 March 2011 10:15 To: PICLIST [email protected]

Hi, I like the idea of direct to PCB resist printing, but don't really have the time to modify my own printer. Does anyone know of where I can get a pre-modified printer for this purpose?

http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist


From:¬†V G¬†[email protected] Date: 22 March 2011 06:38 To: PICLIST [email protected]

Hm. I guess not :(


From:¬†Michael Watterson¬†[email protected] Date: 22 March 2011 06:58 To: "Microcontroller discussion list - Public." [email protected]

Photo exposure is better.

Iron off laser toner next best. Discussed previously here

Any other print solution will be poor


From:¬†V G¬†[email protected] Date: 22 March 2011 08:53 To: "Microcontroller discussion list - Public." [email protected]

Sorry for not trimming, replying from phone.

You say photo exposure is best. Would you still say it's the best if the method is using positive photo resist spray and developer? Or is it only good when using pre-sensitized boards?


From:¬†Michael Watterson¬†[email protected] Date: 22 March 2011 09:10 To: "Microcontroller discussion list - Public." [email protected]

Never used the spray on. I imagine the board needs to be very clean. polished and degreased just prior to spray.

--


From:¬†Byron Jeff¬†[email protected] Date: 22 March 2011 11:32 To: "Microcontroller discussion list - Public." [email protected]

This is a current topic of interest for me. Basic parameters:

  1. Single sided, one off, SMT boards for hobby prototyping. So occasional processing (not too complicated) and ultra quick turnaround (the faster, the better, ideally 1 hour or less) are at a premium.

  2. Most likely targets are SOIC, 0805/0603 type parts.

  3. KiCAD is the development target (may or may not be relevant)

What is the best method using the following priorities (in order):

  1. Speed from printing of design to population ready.

  2. Process repeatibility both in terms of producing a correct board with the process and producing repeat boards using the same process. Presume that this is the occasional hobby board, not a production setup.

  3. Cost per board.

In short if I could print chips directly onto the PCB, that would be great. Impossible, but great. Right now I'm looking at using a PCB hot plate type setup for soldering. So the faster I can get setup, the faster I can get finished.

I'm planning on testing both the Toner Transfer and the Photo resist with precoated boards. Both seem to be about the same amount of time in terms of speed. Overall the TT method seems to be cheaper as precoated boards seem to run about 3x the cost. So it seems to me that the real question is process repeatability.

Thoughts?

BAJ

Byron A. Jeff Department Chair: IT/CS/CNET College of Information and Mathematical Sciences Clayton State University http://cims.clayton.edu/bjeff


From:¬†Bob Blick¬†[email protected] Date: 22 March 2011 11:43 To: "Microcontroller discussion list - Public." [email protected]

Hi Byron,

I've tried using an XY pen plotter directly to PC board and never got good enough etch resistance. All over the net there are recommendations for the RED Staedtler Lumocolor pens but even they are not good enough.

I have used spray-on photoresist. It's OK except for the hairs and dust. In other words, not good for fine pitch because you will have bad spots.

Laser toner transfer is sensitive to your ironing pressure and temperature. I always print a border around my artwork to act as a pressure buffer. It seems to even out the pressure near the edges. Fair to good results if you have finesse. Prepare for lots of do-overs and some touchup before and after etch.

Presensitized board works really well. No question, this is the way to go if you want quality. And unlike the other methods it takes very little talent. Your first board will be good and every one to follow.

I tend to do toner transfer because I am drawn to how immediate it seems, and the fact that you don't really need any consumables. But then after I have ironed on and cleaned off the same board three times before I get a transfer good enough to etch, I rethink my choice of technology, wishing I'd used presensitized board instead. And it's not like there are no consumables, I use acetone to clean the board and lacquer thinner to remove the toner.

Note to self: Since I don't make more than a dozen boards a year I should always use the presensitized board.

Cheerful regards,

Bob

-- http://www.fastmail.fm - A no graphics, no pop-ups email service


From:¬†Byron Jeff¬†[email protected] Date: 22 March 2011 12:41 To: "Microcontroller discussion list - Public." [email protected]

Bob,

This analysis was extremely helpful.

I started working my way through the presensitized boards the last time I was on this roller coaster but did not complete the job. Let me run a brief description of what I have read and see if there are any errors in my thinking:

  1. Print mirror of circuit onto transparancy sheet at max toner setting.

  2. Bind sheet face down (and flat) to presensitized board. Cover with real glass as it is transparent to UV. Do this in a low light environment.

  3. Expose assembly to UV light. Sunlight will work but a UV light box is better. Mine is a black light installed in a toolbox. Never got a clear number on exposure time. Seems to be trail and error but consistent once you get it to work.

  4. Peel the transparancy and there should be a outline image of the circuit on the board. Run the board through the developer (some say caustic/washing soda is OK, others hate it. Suggestions?) until the exposed parts a removed. Do not do it too long or risk undercutting the solid unexposed resist.

  5. Etch the board.

  6. Remove the rest of the photoresist. A bit unclear here. Is this a light and develop a second time step? Or a physical process

Should be ready to shake and bake after this.

On this recommendation, I will attempt this method first. There seems to be repeatability issues with the toner transfer method.

Thanks for the input.

BAJ


From:¬†Oli Glaser¬†[email protected] Date: 22 March 2011 12:21 To: "Microcontroller discussion list - Public." [email protected]

I agree totally - I have used spray on photoresist (messy, difficult to get even and contaminant free) and Toner Transfer (good, but not as accurate/repeatable as photoresist) With hot etching fluid and agitation you will get fast etching times (~5min) and near board house resolution (we get down to around 0.2mm trace width) after a little practice. Worth investing in a UV light box that gives even exposure, and a decent heated etch tank. However you can get good results with a tray in hot water and a source of UV - I used an old sunlamp to start with, worked perfectly.


From:¬†AK¬†[email protected] Date: 22 March 2011 12:21 To: "Microcontroller discussion list - Public." [email protected]

When using 'scuffed' shipping label backing and a laminating press, I've found toner transfer to be very reliable and precise, even using it for some small BGA work.  Posted more details here a long time ago, if you're interested.  The good thing about using the mailing label backing is that it peels right off, no soaking, scrubbing, or developing needed.  Just my experience.

Andrew


From:¬†IVP¬†[email protected] Date: 22 March 2011 12:30 To: "Microcontroller discussion list - Public." [email protected]

I'd agree with that. The human component is the important variable. Repeatability and detail is there for the getting

Take these examples

PIC + quad amp + 0805 R and C. Very small text under the 'JC 3.11' is my note for the board size. It is just about readable (if you know what it's supposed to read. FWIW it says, mirrored, 1.85 x 2.65  4.70 6.74 @ 600 dpi)

http://home.clear.net.nz/pages/joecolquitt/DIP+SMT.jpg

Printout (0.1" pitch pads)

http://home.clear.net.nz/pages/joecolquitt/detail.gif

Result (a little out of focus, better looking in reality)

http://home.clear.net.nz/pages/joecolquitt/detail.jpg

I read one person's account where he uses a hot-plate with a weight to apply a known pressure for a known time. That's something I'd like to investigate. My gauging of iron pressure is fairly good and but I'd rather it be controlled, for a more consistent Toner Squash Factor, which causes holes to shrink and tracks to widen. That said, SOIC 0.05" pitch is quite easily achievable

Joe


From:¬†Oli Glaser¬†[email protected] Date: 22 March 2011 12:43 To: "Microcontroller discussion list - Public." [email protected]

Tracing paper works just as well (and is cheaper) The UV gets through fine. Varies with power of light (and I think resist type, so try to stick to one) so a bit of trial and error - Good idea to print a small test board, consisting of traces (with corners) from 1mm down to 0.1mm, a few SMD footprints (TQFP, QFN) and some through hole pads with thin annular rings. Expose a few of these, gradually adjusting time and note down what works best. I use Sodium Metasilicate, it is a lot better than Sodium Hydroxide (Caustic Soda) You don't have to get the timing so accurate (i.e if you leave it in a second too long it won't strip the resist off) Either - you can shove it under the light again then rinse in developer (I do this way) Or I think some folk just use an abrasive pad to clean it off, which I do anyway afterwards to clean the copper, then run a bit of isopropyl alcohol over it. You can actually leave it on too I think - IIRC some resists act as a flux, check the info/documentation on whatever board you buy. Never tried it so not sure how it compares. The steps you outlined look about right overall to me - this is a good page on board making I found very helpful to begin with: http://www.electricstuff.co.uk/pcbs.html


From:¬†Bob Blick¬†[email protected] Date: 22 March 2011 12:58 To: "Microcontroller discussion list - Public." [email protected]

I would verify if the density setting actually does anything. Every printer is different and on mine it was turning off "economy".

Also you can use cheap 20 LB paper in a pinch if you don't have transparencies.

I've been told inkjets work OK too, in high quality mode. I've used glass and plexiglass and not noticed a difference. I thought glass blocked more UV than plastic?

I have had problems peeling it off afterward. The toner sticks a little bit. Sunlight is nice because it is very much like a point source and you can put the printed side out and still get focus. But if you already made a mirror image that won't work because everything is reversed.

Timing sunlight is near impossible. I made a cumulative timer but never got the right sensor/filter combination to match the sensitizer.

With a UV box you must get your transparency touching flat on the board everywhere.

Timing is trial and error, but it is pretty forgiving, 2:1 once you get in the window. When I was teaching we made our own solution with lye. That was before it got recognized as a component to make meth and consequently harder to find. Now I use the recommended developer. I am a big fan of lacquer thinner, it removes almost anything.

Cheerful regards,

Bob

-- http://www.fastmail.fm - mmm... Fastmail...


From:¬†Bob Blick¬†[email protected] Date: 22 March 2011 13:04 To: "Microcontroller discussion list - Public." [email protected]

Yes, I remember your suggestion about label backing and adopted it, thank you.

All it takes is to ask someone who uses a UPS printer and then you have an unlimited supply of backing paper :)

A laminating press would make a big improvement, I'm sure it would make my boards lots more consistent.

Best regards,

Bob

-- http://www.fastmail.fm - Send your email first class

--


From:¬†Sergey Dryga¬†[email protected] Date: 22 March 2011 17:31 To:¬†[email protected]

Both glass and some plastics absorb UV, but at the thickness tipically used (~1 mm for glass) the absorbance is not too high.  More important is that the glass is "optical quality", without swirls. I used a fluorescent lamp at 15-20 cm from the board/mask/glass stack.  It was while ago, but IIRC 75W lamp is OK.  Some even reported the use of 100W incandescent lamp.  It might not work with all sensitized boards, I got mine from Jameco, the brand is DATAK I believe. I scrubbed with a scrubber/foam pad sold for kitchen cleaning. As last step, 200-400 grit sandpaper and water rinse.  I used purified water for final rinse since tap water often has too many minerals in it (actually I have never tested if just tap water is OK, seems easier to just rinse in distilled water any way).

Sergey Dryga http://beaglerobotics.com

V G [email protected] 22 March 2011 18:45 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] On Mon, Mar 21, 2011 at 7:21 PM, AK [email protected] wrote:

When using 'scuffed' shipping label backing and a laminating press, I've found toner transfer to be very reliable and precise, even using it for some small BGA work.  Posted more details here a long time ago, if you're interested.  The good thing about using the mailing label backing is that it peels right off, no soaking, scrubbing, or developing needed.  Just my experience.

Hi. Where do you get label backing paper?

[Quoted text hidden]

AK [email protected] 22 March 2011 18:56 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] On Tue, Mar 22, 2011 at 2:45 AM, V G [email protected] wrote:

On Mon, Mar 21, 2011 at 7:21 PM, AK [email protected] wrote:

When using 'scuffed' shipping label backing and a laminating press, I've found toner transfer to be very reliable and precise, even using it for some small BGA work.  Posted more details here a long time ago, if you're interested.  The good thing about using the mailing label backing is that it peels right off, no soaking, scrubbing, or developing needed.  Just my experience.

Hi. Where do you get label backing paper?

Generally free as a result of shipping other items, using this: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160516738494 [Quoted text hidden]

V G [email protected] 22 March 2011 19:00 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] On Tue, Mar 22, 2011 at 2:56 AM, AK [email protected] wrote:

Generally free as a result of shipping other items, using this:  http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160516738494

Thanks! Are the label backings better than photo paper as recommended everywhere? [Quoted text hidden]

AK [email protected] 22 March 2011 19:43 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] On Tue, Mar 22, 2011 at 3:00 AM, V G [email protected] wrote:

On Tue, Mar 22, 2011 at 2:56 AM, AK [email protected] wrote:

Generally free as a result of shipping other items, using this:  http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160516738494

Thanks! Are the label backings better than photo paper as recommended everywhere?

I began with photo paper as described elsewhere.  My experience has been that a properly prepped backing transfers more cleanly and with much more ease than paper.  In fact, some sheets I've used multiple times after the transfer.  It's likely that you'll get finer details with a refined optical masking process as described by others, but you can't beat this toner transfer process for speed, cost, lack of chemicals, and simplicity. [Quoted text hidden]

V G [email protected] 23 March 2011 08:52 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] On Tue, Mar 22, 2011 at 2:56 AM, AK [email protected] wrote:

Generally free as a result of shipping other items, using this:  http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160516738494

This is cool. I asked the guy for samples. Hopefully they work out. [Quoted text hidden]

Ing. Marcelo Fornaso [email protected] 23 March 2011 10:20 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] I'm a little afraid of using this sheets on my laser printer because their surface looks like plastic...

Don't you think there is any risk of fusing it into the printer?

Marcelo Fornaso


From: V G [email protected] To: Microcontroller discussion list - Public. [email protected] Sent: Tue, March 22, 2011 5:52:05 PM Subject: Re: [EE] Direct to PCB printing (Inkjet) [Quoted text hidden]

Robert Rolf [email protected] 23 March 2011 10:30 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] There are generally two kinds of 'clear plastic' sheets out there.

The kind used for overhead transparencies, which have an absolutely glossy surface, and which WILL melt and destroy your printer, and those that are made of acetate, and which are a bit smoky and have a very fine texture surface for the toner to grab on to.

If in doubt, put a soldering iron to them. The dangerous plastic will melt nearly instantly, and stink, the 'laser' grade will curl but you'll have to apply a fair bit of heat to melt into them.

If in doubt, don't use them.

R

Ing. Marcelo Fornaso wrote:

I'm a little afraid of using this sheets on my laser printer because their surface looks like plastic...

Don't you think there is any risk of fusing it into the printer?

Marcelo Fornaso

[Quoted text hidden]

Bob Blick [email protected] 23 March 2011 10:37 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected]

On Tue, 22 Mar 2011 15:20 -0700, "Ing. Marcelo Fornaso" wrote:

I'm a little afraid of using this sheets on my laser printer because their surface looks like plastic...

Don't you think there is any risk of fusing it into the printer?

With label attached it is intended to run through a printer. I haven't ever had a problem.

It is too slippery to hold the toner until you scuff it up a little bit with a tissue or paper towel.

I don't run it full letter size through the printer. I attach a piece larger than the design on to a sheet of normal paper using a label at the top of the backing paper. Center the design on the sheet so the leading edge of the carrier paper has nothing additional on it.

Cheers,

Bob

-- http://www.fastmail.fm - A no graphics, no pop-ups email service

-- [Quoted text hidden]

Ing. Marcelo Fornaso [email protected] 23 March 2011 12:05 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] Ok. I got the idea and will give it a try.

Thank you

Marcelo Fornaso


From: Bob Blick [email protected] To: Microcontroller discussion list - Public. [email protected] Sent: Tue, March 22, 2011 7:37:54 PM Subject: Re: [EE] Direct to PCB printing (Inkjet)

[Quoted text hidden]

Vic Fraenckel [email protected] 23 March 2011 12:59 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] Do any of you following this thread know that there is a Yahoo Group "Homebrew_PCB" that discusses most of the issues that you are discussing here?

Check the group out here:

http://tech.groups.yahoo.com/group/Homebrew_PCBs/

Vic

Victor Fraenckel KC2GUI windswaytoo ATSIGN gmail DOT com [Quoted text hidden]

William "Chops" Westfield [email protected] 23 March 2011 13:39 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected]

On Mar 22, 2011, at 3:20 PM, Ing. Marcelo Fornaso wrote:

I'm a little afraid of using this sheets on my laser printer because their surface looks like plastic...

Sheesh.  Find someplace that uses laser-printable label sheets.  Or even buy some.  Use any remaining labels as ... labels or something, leaving you with a backing  sheet suitable for this sort of toner- transfer.  Any laser-printable labels will have a non-melting backing sheet; probably silicone based.

Try the library.  Our middle school library prints bar codes on sheets of labels for their new books.  This usually doesn't fill up a sheet, and the software doesn't support exact placement of the barcodes on partially filled sheets, so the remaining labels get stamped with the school name/etc for tagging magazines and such.  Eventually they're all used up and the backing sheet is thrown away.

Some backing sheets are nicer than others.

I prefer the destructively processed glossy magazine paper route. The reason that the label backing sheet works so well is that toner doesn't stick to it.  Which also can mean that it's subject to flaking off somewhere in the process before it gets to your board...

=======

Professional PCB fabrication services get cheaper and cheaper, and more and more convenient to amateurs.  Batched hobbyist services (batchPCB, dorkbot) have "solved" the minimum board size problem, so that you're no longer penalized for wanting a very small board. Direct-from-china suppliers (Itead, Seeed) are doing the cheap- prototypes (~$20) with long lead time thing so that you're no longer forced to use a high-priced quick-turn supplier for "prototypes."  The only remaining advantage of home fabrication is that simplicity (single sided, 16mil design rules) will get you faster and cheaper. But it's getting harder and hard to justify.

BillW [Quoted text hidden]

V G [email protected] 23 March 2011 16:45 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] On Tue, Mar 22, 2011 at 9:39 PM, William "Chops" Westfield [email protected]: [Quoted text hidden] $20 with shipping and tax compared to a few dollars and instant turnaround times is not hard to justify. [Quoted text hidden]

William "Chops" Westfield [email protected] 23 March 2011 17:27 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected]

On Mar 22, 2011, at 9:45 PM, V G wrote:

$20 with shipping and tax compared to a few dollars and instant turnaround times is not hard to justify.

It depends.  Couple bucks for blank copper clad.  Couple bucks for etchant.  Significant bucks for the high-grade ink cartridge (for direct to PCB printing) (which may or may not dry up between PCBs (I hate inkjets!)) or a couple bucks for special transfer paper or transparency paper.  Couple bucks for drill bits.  Couple bucks for tool to cut the PCB material.  Moderate amount for an inkjet printer to modify, or for a laminator, or for an iron, or for a contact exposure frame.  Couple buck for other chemicals, sandpaper, etc.

I dunno.  I've spent a couple $K for an LPKF (mill) to get that "instant turnaround."  But it's not really that "instant", and I'm increasingly uncertain that it was a worthwhile purchase.

BillW [Quoted text hidden]

V G [email protected] 23 March 2011 20:17 Reply-To: "Microcontroller discussion list - Public." [email protected] To: "Microcontroller discussion list - Public." [email protected] On Wed, Mar 23, 2011 at 1:27 AM, William "Chops" Westfield [email protected]:

It depends.  Couple bucks for blank copper clad.

Agreed.

Couple bucks for etchant.

That's a one time thing. A bottle will last a LONG time. If you use the HCL/H2O2 method, you can make it last forever and it's VERY cheap.

Significant bucks for the high-grade ink cartridge (for direct to PCB printing) (which may or may not dry up between PCBs (I hate inkjets!))

Or, just a laser printer (that most people have anyway) on label backing paper that you can get for free.

or a couple bucks for special transfer paper or transparency paper.

It'll last you a lifetime.

Couple bucks for drill bits.

Tungsten carbide bits will last you pretty much forever and they're pretty cheap.

Couple bucks for tool to cut the PCB material.

Again, it'll last you forever.

Moderate amount for an inkjet printer to modify, or for a laminator, or for an iron, or for a contact exposure frame.  Couple buck for other chemicals, sandpaper, etc.

Sandpaper costs pennies, most people already have a laser printer, most people have a clothes iron.

I dunno.  I've spent a couple $K for an LPKF (mill) to get that "instant turnaround."  But it's not really that "instant", and I'm increasingly uncertain that it was a worthwhile purchase.

So what you only really need is the copper board. Everything is already lying around somewhere or will last "forever" or costs pennies. [Quoted text hidden]

\$\endgroup\$
2
  • \$\begingroup\$ this is not an answer, Try giving us the information here. Use the link as a helpful reference. \$\endgroup\$
    – Kortuk
    Aug 5, 2011 at 13:31
  • \$\begingroup\$ @Kortuk Howzat! ? \$\endgroup\$
    – Russell McMahon
    Mar 30 at 5:02

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