Sonsivri

Hi guys,

I just newbie in electronic hobby even I have interest in this hobby for a long time ago.

Just to ask opinin (pro & cont) & way ... how to transfer PCB layout to copper board.

For now, I'm using tonner transfer (using laser printer & coated paper) ... result: not so good  & photoresist board ... result : very good but the board are very expensive.

Anyone using graving machine to make a PCB board ?

Thanks for info.

Thanks Dax,

Currently I'm doing it (toner transfer) using 2 type of paper (that available in Malaysia which I know & tried)

1. Canon Glossy Photo paper ... GP-401  ... A4 190g/m2

Result : very good ... no cutting line & no spread line.... can push the iron as much as you much

Problem: When take the paper from copper board, there is wax on the PCB especially in pad's pin hole and so hard to remove it even using tooth brush, I still need to check if it still there... so then no hold in pad as for guide the drill as a starter.


2. HP Photo laser paper ... A4 120g/m2

Result : not so good as the line (toner) being cut at a few place (the toner fell off with the paper). Cannot push it (using iron) too hard, it will spread the toner and it will short circuit the PCB track.

Good thing : No wax remain in the pad's hole ... so the acid will etch the pad and make the hole as drill starter guide.

Repair : Using lumocolour pen from Steadler & using buble etching to expedite the etching process.



Dax,

Please share with us the paper's part number and how much (for price reference & how many pieces)?

One more thing, how you make Dbl side board in short point ( if eleberate more, more better).


Anyway thanks for info and souces ....

Sorry for my english .....

Other paper ... but not so good compare to canon & HP ... so far:

1. Trace paper  ..
2. label paper
3. other low end glosy photo paper ...

Dax,

Thanks a lot for sharing your info, man.

I have some more thing to ask for guidance ( if you and/or other friends can help and wish to spent some time to comment it.... :D)

1. For PCB CAD, now I'm using Eagle 4.16 and only use single side board. I try to do (in eagle) to make double side board by grouping a component ie resister and put it in one place, capacitor in another place, connector in next other place and so on.

The problem (may be not a problem), when I run autorouting (with TOP & BOTTOM are set), the result most  of the time 100% routed but the saiz of PCB are >< the size of single side board.(FYI, I re-create the component pad ie resister because of the original pad size very small and some time being take out by dril) and A LOT OF VIAS.... some time about 40 vias or more.

To me, doing double layer like this ... not so good as you get more via instead of easy place the component.But the board size not so diffrent( double side vs single side board).

So may be, you can share some of your experience & guidance on how to make good double layer PCB board.

Normally how many vias you have on the board (average for 3 x 4 inch)? or any example ? How the steps to minimise vias?

2. Let say for PIC uC project, how small the track did you usually used?I normally use 30mil and 22 mil clearence (in eagle) to avoid any toner spread on the board.

3. For CAD software, what software you use ? Eagle or Proteus or ?Any good manual/info to study ?

4.If any, any step you follow in making routing .. ie manually doing VCC & GND first and after that go with autorouting?

5. How long the time you take to make one double side board in average?start from print upto finish of drill & etching process?

6. Any info to convert eagle file to proteus & proteus to eagle? also any proteus manual?

7. If any picture of your board, can you share here ... so I can take close look about the quality of board  (PCB layout and clearence) as for my benchmark.

Sorry for toooooo many guidance to ask .... :D

Thanks in advance for any guides / comments.

Hi Dax,

Thanks again for your good sharing ... and sorry for my english :D

Ok ... for the number 1 , I repeat again ( in diffrentway & hope you can understand my english ... :))

1. FYI, I'm using eagle as PCB CAD. In eagle, I can do single & double layer (basically can make upto 16 layer max but not me ... he he ).

As for now, I just making PCB board as single layer only. I  do it (single layer) by arrange the components base on the schematic ( to reduce jumper & to simplify autorouting) and do autorouting for single layer only. If there is some unroute track(after doing autorouting), I will route it manual using top layer & bottom layer  and will use a copper as bridge for the top layer to connect to bottom layer.

For double layer, I just try making it in PC (using eagle) and print out on the paper for top layer & bottom layer (but not doing any double layer bo ardyet).


Ok my problem/question are :

a) When I make single layer (let say for USB FTP-USB programmer), the PCB layout size is about 2.5 x 4 inch .... and when I make 2 layer (just print on paper) the size roughly about the same size.

For the 1 layer, I need to think hard in oder to get good arrangement  all the componets on the PCB (for the best autorouting) with few jumpers. But for 2 layer, I can put the components as where I like it to be.So for comparison (in my case):

- 1 layer :
    Pro : less jumper ( dont have via)
    Cont : time consuming  to get all components in good arrangement
    PCB Size : 2.5 x 4 inch

- 2 layer :
    Pro : require little time to arrage component(because I arrange as where I like) & dont have jumpers.
   Cont : A lot of VIAS (sometime upto 40++ via )
   PCB Size : allmost same (because must give some space for via)

- So any experience / advice / steps  to share in order to get ( 2 layer PCB ) with less via & small size ?
- How do you do in making 2 layer PCB?
- You do 2 layer manual / autorouting / half manual ?
- What you prefer ... making single layer / 2 layer ?

2. Any comment for autorouting in eagle / any experience ?

3. Is the any auto placer in Protel 99 SE sp6 ?

Thanks in advance for your info sharing / guide ...:)

Dax,

Thnks for your info & advice ....

Sorry for my english ....  :D ... need to learn some more ....

Any way ... thnks a lot & i will move to Protel as you suggest .... may be I will take some time  .... & need to find a manual for that also.

Also thanks for your time to show a demo of staple 'effect'.

Dax,

Thnks very much.

Now, I succesfull done with HP Photo laser paper .... the quality about 99.5% (sufficient enough for me) ...

I need just to touch-up just one place ... so it already very good.


I just use your way (just put tissue/toilet paper between iron & HP Photo laser paper & press the iron as much as I want it).

I do this about 1-2 minit for one place ... and lift the iron and put the iron with presure in another place ... and so on.

After that, I put it(PCB)  into  (while still hot) liquid dishwashing detergent and for about 30 minit. (my best result: I put it in a whole night and in next morning, the paper (HP paper) already separated from the PCB).

If somebody one to know in details, please just let me know.... I want to contribute back this knowledge as my payback to this site (especially DAX).

If you have enough time 9~1.5 hours per board) and a nice laminator, best will be toner transfer.

If you don't have time or don't want to waste time or have money - photoresist !

Hi
I've tried using a CNC mill to make circuit boards. It is very time consuming and quite expensive (fine mill bits  are not cheap). It takes quite a while to get everything lined up correctly and then it might take 2 or three hours to mill it. The big advantage is that it will drill the holes for you.
If I am just making one board I use the laser and cheap photo paper method and etch it with hydrogen peroxide and hydrochloric acid. I can have a board ready for drilling in about half an hour using this method.

To everybody who is using the iron on method
DO YOURSELF'S A BIG FAVOUR AND BUY A LAMINATOR!
you can't beat the consistent heat and pressure the lamintator gives you over manually ironing,I used an iron for years and had good results but the laminator makes it way easier and with way better results and if you use press & peel blue with a laminator I get 100% RESULTS 100% OF THE TIME.
And by the way I never could get good result's with press & peel blue using an iron but excellant results using it with a laminator.

other website for toner transfer

http://myweb.cableone.net/wheedal/pcb.htm
http://www.riccibitti.com/pcb/pcb.htm
i think toner transfer is more easy and low cost than Photoresist

Make sure you bought the high temperature type of laminator machine.  there are two types: low temperature and high temperature. (they are not marked, and you have to find out yourself)   the low temperature type can not melt the toner resin and unable to transfer it to the PCB correctly.   

http://www.pulsarprofx.com/decalpro/Vertical/1_MENU/1d_Components/Info_GBC_Personal.html
13 popular laminators we tested for use with DecalPRO® and the results are in...
THOSE THAT DO WORK!
Find on eBay and/or office supply stores:

Mfg: GBC

• H-100 (current - 4" model)
• H-200 (discontinued - 9" model)
• H-210 (current - 9" model)
• 250 HS (current - 9" model)
• H-300 (current - 12" model)
• Creative (discontinued - 9" model)

Those That DO NOT WORK!
Mfg: FELLOWES

• Cosmic Laminator (MPL-2)
• EXL-95-2
Mfg: STAPLES

• LM1910
Mfg: ROYAL

• PL-100
• PL-2100
• PL-2112
Mfg: 3M

• 9" Scotch
Mfg: BANNER AMERICAN

• QuickFinish PL100

Can you please detail the procedure of using the laminator for PCB transfer?

exactly the same as the iron on method except you put the paper and pcb through the laminator instead of ironing,the main differance is the laminator has even heat and pressure where ironing is only hit and miss unless it's a small board

I use tonertransfer with laminator and glossy newsprint from magazines, really pleased with the result. Have never gotten really good results with laser/inkjet papers. Only downside is that it's trickier to see your printed pattern since the paper is already printed on.

Have any one using screen Print for pcb. I think its easy and huge pices for pcb. most of the time i am using this procedure. if some want to say about it then let me know. ;D

HELLO
I AM USING TONER TRANSFER METHOD ONLY .BUT I TRIED SCREEN PRINTING METHOD.IT IS TOO MUCH TIME TAKING PROCESS TO PREPARE THE IMAGE.IT REQUIRES TOO MUCH CLEANING FOR THE MESH AFTER THE JOB IS DONE.SO AGAIN I CAME BACK TO TONER TRANSFER METHOD.
I AM ETCHING OUT THE PCB AND AFTER DRILLING I AM DIRECTLY USIING THE PCB FOR SOLDERING.IF I LEFT FOR SOME HOURS ,BOARD IS GETTING RUST.SO I NEED A GOOD METHOD FOR TINNING AND SOLDER MASK.
BBARNEY THE IMAGE U HAVE SHOWN IS IN GREEN COLOUR.I THINK IT IS SOLDER MASK. CAN U GIVE SOME DETAILS OF TINNING AND APPLYING SOLDER MASK TO THE PCB. I WILL BE THANK FUL TO U AND ALL .

we will be thank ful to u :D
i use photoresist and i get really good results
i'm using 2 neon uv-c but i think the plexiglass is blocking them
so the pcb need an exposure of 15 minutes...
on the other hand it's not too bad, i always forget the pcb under the uv for 20-25 minutes without overexposures... :P

toner transfer is good
look kit and special paper
http://www.pulsarprofx.com/PCB/a_Pages/6_Products_and_Store/_Store.html
http://www.metrafo.ro/info.html?cod=TES200

the solder tinning is called liquid tin and made by MG Chemicalsl you soak the board in it for 5 min and the green color there is actually transparent green laquer spray paint made by Testor the hobby model paint manf.
http://www.hobbylinc.com/prods/s_tes.htm
http://mgchemicals.com/products/421.html

i've been trying many kind of of paper for toner transfer with heating and pressure (iron or others), and in my experience  sticker paper (printed in the smooth sliperry yellow side) which result the best for me. after ironing let the pcb blow with cool air (i use ordinary fan), until the paper lose/drop by it self from the pcb. then i always see the best result, no carbon left in the paper no carbon crack in the copper, just make sure before ironing get the copper washed ,clean and free from dust and fat (probably fat from your hand, just don't touch the copper side). and make sure the pcb is real flat to accept the transfer (no bad pcb cutting):)

I tried with magazine paper and had different expierences... I tried with a color page, the face page (is thicker than the others) and a white page with text. The best result was in a white page. I used toner transfer, used an 1200 dpi image and printed with 1200 dpi resolution (almost any laser printer today makes this resolution). I used the Iron, set in Cotton (controlled the temperature for 180-190 celsius) and pushed as many i could. I transfered a 4 mil text with sucess... And the net width was 14 mil. Perfect transfer of MSSOP part (clearance of 8 mil) , no cuts or fails. The secret is the paper... The paper cant dissolve easily with water... Cannot have many recycled content. And cannot have color in the back or in the front... If you want to make a double face... I dont know what happen, but it appears the paper shrinks, difficulting to center. With white paper, it didn't happen.

I bought a Laminator today, the GBC H-210, and try the transfer method with it.
Even at the higher temperature setting it cannot melt the toner for transfer to the PCB.

It is very disapointing.  I tried with different types of paper but still no result.  So photoresist is still the best method for me.
Ironing for very small PCBs.

pl4tonas
What kind of  printer are you using and what paper.if you can find a few sheets of press&peel blue I'am sure you will be impressed also the pcb must be sqeaky clean.there are a few laser printers that don't work very well and the laminator you bought should work and the paper is a factor to you will just have to experiment to find the right combo

Hello bbarney,
Thanks for your reply.
I am using an HP Laserjet1000 printer.  I tryied tracing paper and magazine glossy paper. 
Today I will make some more tests since yesterday I haven't enough time to play.

With an iron, the magazine paper worked but only for small PCB.  For larger PCBs it does not work very well.
I will carry some more experiments during the next days to find out the correct/proper combination.
Press&Peel is not available lockally so I have to order it from internet.  I will give it a try as a last resort.

Upon success, I will post my results.
Regards
P.

A few years ago I used serigraphy method. It is cheap and serially producing PCB is possible. Photoresist methos  think may be same. I am not sure exatly.

pl4tonas I'am sure it's probably the paper you are using as the printer and laminator are both perfect to do it HERE'S LINK IN CASE YOU MISSED IT
http://www.pulsarprofx.com/PCB/a_Pages/4_Products/4d_Toner_Applicator/Toner_Applicator.html

Remember! 
 Glossary paper and laser printer method is better than press_n peel from internet shop
 1$ A4 sheet!

i made some pcb's with my router milling machine and use eagle software. i use a plugin to generate g-code
to mill a pcb. After that i can drill the holes in my pcb using my milling machine

I disagree with that,I've used glossy paper and my results were not worth the effort and $1 per sheet is cheap if it works everytime not to mention that I would probably make 4 or 5 different pcb out of that one sheet so $1 a sheet is pretty cheap for what I get which are good boards the first time and not frustrated making it over and over till it comes out right. 

ive done toner transfer and it worked really well. the trick is to keep the iron pressed on for the right amount of time. touch up anyparts with a felt tip pen

We use a "Sherline"  type small CNC machine with a conical carbide engraving bit on FR4 clad PCB. This works VERY WELL for everything BUT multi=layer boards...

We create artwork/gerbers in Protel, then use a prog called "DeskPCB" to do isolation cutting (like LPKF or most other prototyping PCB systems).

Saves time and $ when doing small-run or single protoyping

Cheers-TuvoJ

Photoresist give good result (SO 1.27mm is OK ), but for little number PCB take more time then toner, more chemikal operation and spetial light(be caraful may eyes damage). But toner give more unstable result in chemikal protekt. I like use photoresist.

I have made a small guide (with lots of photos) on how to expose an etch your own PCB's using a homemade UV exposure chamber:

http://ptyxiouxos.net//greekbotics/user_projects/Flight_Simulator/electronics/ThanosPCBmaking/PCBmakingGuide.htm
 (http://ptyxiouxos.net//greekbotics/user_projects/Flight_Simulator/electronics/ThanosPCBmaking/PCBmakingGuide.htm)

I hope that helps

Regards, Thanos
Greece

I use fine quality asetat transparent surface and controlled iron for lines uncorrupt

Posted on: March 03, 2008, 11:26:36 11:26 - Automerged

---

Toner transfer method is very cheap,and photo resist method is costly but it profetional quality.

mkarim

Alternative PCB......

http://europa.spaceports.com/~fishbake/acb.html

I got my best results by using an adopted CNC with a minimum 200 microns milling cutter... It gave me the best registration for 2 Layer boards (top layer <-> bottom layer) due to automatic registration of the bore holes

Hello
I met someone recently this method I get a manual?
Thanks

best method is using laser printer. I suggest..

Hello everyone!

I hope this short movie are very useful for toner transfer & etching & very cheap method !
http://www.youtube.com/watch?v=tTxPnZLpp_8

How interesting !
I have seen pictures of that work .
Would you share what combination of software for PCB design and then for CNC you use ? An links for them ?

Thank you

Hi... does anyone have a good idea to make a precission double layer PCb using toner transfer?

I'm using Altium Designer (available on this board) for circuit simulation and pcb layout.
The layout of Altium is exported into extended Gerber files. These files can be read
by IsoCAM (http://www.isolationmilling.com/index.htm).
I use IsoCAM to determine wether I want to do isolation milling or remove unwanted
copper completely (both modes may be combined by selecting copper areas to be
milled). Again I export gerber files which our cnc @work
is able to use...

personaly  I am not a expert in pcb , but I can tell you about my experiences, I tried the first time I made  one  with a tone transfer and  I think I did heat too much  the  iron and  the pcb was a mess! I lost the copper!, so  the next time I tried I did  it by  using a fine point permanent marker  and  after make the tracks I gave  it a acid bath, and  It worked perfectly, so ..so far I  have not tried  with the toner transfer again , but I have heard that some people got to work with it  very nicely I think it is  just about practice, regarts.

I use press-n-peel sheets, http://www.techniks.com/index.htm , they give a very good result, check their website, they have nice tutorial

I have developed few interface PCB boards using toner transfer (laser printer + iron) successfully after few trial & error for my Explorer-16 dev board.

But the problem is copper strips on the PCB connector is getting oxidised after few days. I have seen many professionally made PCBs have gold plated connector edges, even in Explorer-16 board.

Any one would know whether we could develop that type of gold plated, or other suitable mathod which we could use in home/ hobby environment to stop oxide in the copper PCB connectors.

where  could  w buy  a Lamlinator?, or  maybe we could  build  it? , thansk for your answer. regards.

I have used iron method to transfer toner.
A few week ago I try to use Laminator - the results is very nice!
All is very accurately, no more sticking together tracks.
But I think a temperature needs to be enlage a litle.

I know that using laminators is a very good way to transfer the toner. Which one to buy? Most of them they have temperature range   100-160°C and I think it's ok but I'm worry about the max. material thickness which is 10mil and if the pcb is 1mm and more it might not pass with the toner paper.
Can you recommend me a good brand and model? I want to try this. Thank you in advance!

The reality is that the method is quite old. In the case of INK JET modified to print with indelible ink is already something old, and the results are not very good. If you want to see an example of modification here you leave a link. To my mind the best away remains the silk.

Yahoo!
I am using chinese made laminator SIGMA EL142.
I think any model of laminator will be good.
The main is temperature, and I think a temperature in any model is approximately equal.

I'm worry that the pcb with thickness of 1mm cannot pass through the laminator because I saw that most of the models can handle only 10mil max material thickness. Is that true?
I need a laminator for max 2mm copper pcb + PnP blue sheet

Through a laminator you can pass only the thin type of PCB, the 0,032" thickness.  It has about half the thickness of the standard PCB.

Also have in mind that, you need to pass the PCB about 10 times through the laminator in order to have good results.  This is performed with the heat setting to maximum.  A laminator does not have the heating power of an Iron but with around 10 passes you get much better results. 

Using laminators will give people mixed results and most laminators are not designed to feed a typical PCB due to thickness, this results in your lamintor loosing its pressing pressure overtime in the centre depending on how you insert your board. Also, the temperature is low on most laminators, but since you guys are into electronics, its easy to mod a laminator to operate at higher temperatures, but beware you do not melt the housing.

Laminators are not reliable in the sense that you might have to buy a few to find the right one, and even then, you risk damaging it by continuously feeding over-thick material through.

Using the Iron is the riskiest and most unreliable method regardless of which paper and how you use it, unless your end board is small and single sided.

The most common problems with toner transfer is the printer. Today, most new printers are designed to deposit as little as possible toner on paper, and most toners today are designed to provide the same amount of colour saturation with far less toner present on paper, meaning, its good if you want more pages per cartridge, but bad news if you want more toner on each page for transfer purposes. I have not come across any printer allowing you to choose how much toner you want used, although all have the typical economy, normal and best modes. The problem is, the best modes today give out as much toner as the economy mode 10 years ago.

This is due to better toners being produced and newer laser technology allowing the same print with less toner. You guys also have to note, there are different types of toners and some melt at different temperatures, although not wide on a spectrum, but enough to make some toner transfers successful whilst others fail.

I remember once, the office printer/copier was ordered by the boss to have its cartridges refilled with non-brand toner rather than replacing the cartridge with the same brand toner to save money, which resulted in disaster. The refill toner was melting far too easy and resulted in the pages full of smudges (i say smudge, but its different to that of inkjet...... imagine a stamp being pressed onto a piece of paper extra hard, everything gets bolder) where one letter was joined to the next, a's looked like fat b's etc. Anyway, the printer/copier was also ruined and needed a service.

Also, what happens, is some people find, this paper works for them, or that laminator works for them, then they tell others, forgetting that that particular laminator, and paper only works with a sufficient amount of toner present on the paper to begin with.

Laminator/Iron Method:

For newer models of laser printers, the thinnest possible paper should be used that has a glossy feel, however, you have to watch out you don't use too a thin of a paper otherwise it will jam in your printer as it tears during feed in. For single sided, cut out the circuit from the paper using scissor or others, and place on the ccb (copper clad board/pcb) and feed through your laminator. You can use normal photo/glossy paper, but will not work on most 2005> printers.

If your laminator has a habit to disposition your paper circuit during feed in, then simply use a small strip of masking tape attached on two opposite sides of the board fixing the paper circuit on the ccb. Some laminators require you to feed it in a number of times before the toner sticks to the board, some less and some more, but I have not come across any that does it in 1 or 2 goes. Once you feel the toner has stuck to the ccb, put it in warm or normal temp. water until the paper used tears away without effort. This is where many people go wrong, they try to scrub off, or use slight force to take away the paper which results in cut tracks or other errors. 

Anyway, if you leave it long enough, it should come off easier than a wet tissue, slowly start from areas with less tracks/pads then when entering areas of detail, try to rub your finger across the same way of the majority of the tracks, in other words, rub along the detail, if you have tracks going from right to left, rub from right to left.

If done right you will have a nice toner transfer. Back to the feed in step, to ensure you're laminators springs and pressure quality remains constant over continuous use, feed in the board+paper orientated to allow the widest entry, this may result in you having to feed in a few more times, but allows your laminator to work for such usage longer. On the other hand, if you feed in orientated so the width is the least, you may have a better transfer but you also risk ruining the laminator quicker. This also depends on your laminator, and how it applies pressure,whether by springs etc.

Some of you may find that your printer uses toner that is hard to melt or that there is not enough toner even at best quality, this will normally result in the laminator only sticking the paper circuit on to the ccb, but not transfering the toner, and it will peel off without leaving any trace of toners. 1. this could be due to an improper cleaned ccb, but normally, if it was not cleaned properly, then there should be atleast some sign of transfer. If there is no sign of transfer, then run the thing through the laminator a few times again until it sticks again... whilst its still warm/hot from the laminator, grab the iron and finish it off there.

Iron:

If your laminator does not do the job, it still is a good tool to fix on the paper circuit on to the ccb before ironing. If you are ironing, you have 2 options, either have it on a very hot setting, but be very brief and confident that you are applying even pressure. The second option is to use a medium heat setting, and then taking your time applying pressure.

Make sure the bottom of your iron is cleaning so the paper circuit does not come off or move off the ccb whilst your moving the iron. Don't use steam or any steaming that your iron provides, it does not make much difference and may also ruin the process. One thing you can do, which works well if done right, is straight/immediately after you lift the iron the final time confident the toner is stuck and transferred (I am saying Transferred, but the truth is, the toner will always be sandwiched stuck on both the ccb, and paper, unless the paper you use is special like PnP) then add a few ice cube on the back of the paper.. if done right, the toner due to sudden change in temp. will repel from the cold side (paper side) and stick to the ccb. Then proceed to drop the whole thing in warm - normal temp. water. Boiling or Hot water is not recommended, UNLESS you have bad bond or a different type of toner that works well repelling from paper under such conditions.

Etching:

The etching process is simple, dependent on the etching solution and environment, it shouldn't take more than 5-40 minutes. I recommend everyone to buy a etching bath, it makes the whole process faster, and also allows you to roughly estimate when the etching is done. For ferric chloride solution, add 5-10 seconds on top after you etch each board as its corrosiveness degrades according to usage. Add 20 seconds or more if you are etching larger boards. These times will vary dependent on the ratio of the solution and water as well as how much solution there is for the size of board you use.

UV Exposure Method

The BEST way, and beleive me, I have tried all the previous methods, is to use photosensitve copper clad boards. If you are thinking of spraying your own boards for them to become photosensitive, its not really worth it, unless you have switched to using photosensitive boards and you just want to convert some of your old normal copper clad boards. Buy photosensitive copper clad boards to begin with, and the price difference is not much these days, probably around 0.5 x more than the normal copper clad boards.

The best light source is UV-B tan tubes. You can buy a facial tanning machine for around $50 on ebay that has 4x15watt tubes that is housed with a timer. All you have to do is tilt it so it shines upwards, place a clear piece of glass or open up an empty scanner and take off of the top glass/clear plastic unit with the lid attached an place it on the tan unit. If you want, you can make a custom case using a scanner, and disassemble the tanning unit and place the tubes, starters, ballast and circuitry inside, but personally, I wouldn't bother, because you never know when the winter blues might hit you, which is when the tanning machine will become usefull ;-) You can use UV-A or UV-C but is not as fast as the UV-B tubes.

Use a frosted tracing paper to print on and place over the photosensitve copper clad board, and leave under then the uvb light. You need to use a frosted tracing paper so the uv rays are spread evenly, otherwise you will get areas of overexposure and areas of underexposure. You will also loose the ability to do fine tracks if you don't use froster tracing paper. If you can't get frosted tracing paper, DON'T WORRY, all you need to do, is just frost the glass/clear plastic which you will be placing the boards on and use acetate printing paper instead. There is not much difference on whether the clear plastic/glass panel is frosted or whether you use frosted paper instead.

All you need is something to diffuse the light evenly, and if you find other methods then thats fine too. The only thing is, there shouldn't be too much distance between the diffuser and the printed tracks. The distance between the UVB tubes and the board should be around 5-7 cm. The further away, the longer it takes, the closer, the more chance of uneven exposure. With a diffusor, 7 cm is the optimum for 4x15w spaced the same way as the facial tanning machines.

Anyway, when I started using these 4x15w uv-b tanning light i used to leave my pccb's for around 5-7 minutes, thinking I needed to see atleast abit of the tracks on the photosensitive side before I dip them into the developing solution. Everytime I dipped the board in the developing solution, the circuit got dark quickly on the board and then melted away in a matter of 10 seconds. This was odd, I thought the solution was too concentrated etc. I blamed everything except my exposure time. I then realized 5-7 minutes exposure is toooo much, I now expose my boards for 30 seconds under the uv light, and then dip them into the developer for 20 seconds, then give them a rinse and then off to the etchant.

It is easy to do double sided too, there are numerous way, I will tell you the way I think is the most reliable:

Double Sided:

1. Print-to-file both sides of your circuit board, use photoshop or another photoediting program and align both of your circuits end to end, but with one of the mirrored and the other flipped in a way so when you print, you can simply fold the paper and the circuits will align with each when you look through the paper under light. The gap between the fold should not be much, however, draw a center line in the photo editing suite you are using so you know where to fold.

Once you have printed on paper your circuit design, before folding, trim off excess paper, leaving only 0.5cm / 5mm gap between the edges of the circuit and the trim. Now fold precisely where your center line was, further sharped the fold by going over it with a ruler or something hard, watch out the design does not come off alignment when doing this, keep checking under light and use masking tape etc. if needed to help you.

Remove anything you may have used such as masking tap and place your pccp/ccp in between the paper so its like a pita sandwich. Use masking tape to hold the paper onto the board on both sides so it does not move when you flip it over under the UV light or when passing through the laminator. In the case of UV you should use a tracing paper because acetate is hard to fold etc.

Once you paper is secured to the board, drill 2 holes precisely through to the mounting pads (you need to add some during the design, or add some non-usable pads so you can check your alignment, make sure the pads you add are opposite of each other on both axis's such as ona hypotenuse of a triangle). Now check carefully to see if he holes align with the paper marks. If so, then proceed with lamination/ironing/uv exposure.

In my opinion, the best method for circuit development is the photosensitive method. I have never ever been able to get such detail, clarity and track width as I do with the photosensitive method. It is by far the best method for 3 reasons, 1. It is consistent, you can rely on getting the exact same results each time 2. You can achieve far more detail, surface mount, tqfp, no problem. 3. it is quick

You may have tried it and not been able to get good results, but i strongly suggest to use my method, and also ensure you buy ready photosensitive copper clad boards, and also ensure you use UVB with a diffusor. tw8

Hello i study electrical engιneer, and now learn to make PCB.In my university use protel '98.what is the best program for draw pcb because ths protel 98 is stupid!!!!

Yo persiangulf.

That is a very thorough explanation on home PCB manufacturing.
Congratulations!  for a newbie, you certainly have contributed greatly and more thoughtful than most other oldies and that including me  :P

Now, my request,  I have trouble in following your double sided board explanation.
Could you  give some illustration to that technique?  maybe some pictures etc.

Parmin, nice signature. Double sided is really easy, but I guess the detail above might make it sound hard to some, and as we are human, we all think visually when learning practical things, so image descriptions are always good. I will either draw some images to help you understand, or take some pictures of doing a double sided board. I'll add them here later on today or tomorrow. If there is anything else, let me know so I can add them to the post.

Regards,

PG

Posted on: April 19, 2008, 07:46:27 19:46 - Automerged

---

It's really about preference, but there are a few packages that hit the taste of most people. Here are some of the top ones:

1. Diptrace - Easy to use, nice UI, good library and autoroute function.
2. Eagle from CADSoft - Difficult to learn, complex UI, but powerful program that allows you to virtually design boards for any process with excellent autorouting.
3. Orcad - Fairly complex, tedious UI, loads of features, simulator and various other powerful tools such as the autoroute function.
4. Altium Designer - haven't used this one.
5. Proteus - haven't used it, the screenshot put me off :)

There are others, and there are loads of threads around about PCB Cad packages, but
the BEST one in my opinion is Diptrace. Diptrace is easy to use, with a small learning curve. You won't even have to read the manuals, its one of those programs that you can begin using straight away.

I can't stress how easy it is to use Diptrace, definitely try it, before trying the rest. And if anyone else is using other pcb programs but hasn't tried Diptrace, then PLEASE DO TRY IT!! This is because it helped me stop growing white hairs. It's a likable package.

persiangulf

You seems have done significant R&D on the PCB with various methods, and realy appreciate your nice effort to share your experience in the forum.

Do you ever experiment with plating (Nickel or gold) the PCB copper strips on the board, specially when you have edge connector on the PCB?


.

Hi persiangulf,
I can confirm that DipTrace is realy very easy PCB design software. I have experience using Orcad & Cadstar for many years and their price is so high for the "demo" libraries they provide. First time I see so simple and user friendly interface of DipTrace and in combination with complete set of libraries - I'll switch to it. Thank you for your suggestion!

Hi all:
Apart of the great tuto that persiangulf leave to us i want to share some personal experience about all this:
i dunno if you know the T-shirts transfer irons, they have a large (40 by 40 cms) evenly heated plate and an assembly to press the iron against the base and most of them have a temperature control, so you can make a very decent PCB with just mag paper and a laser printer, i can say that even better than a laminator because you have no chance to damage the unit and no rolls that would move you design when you feed it.
This iron seves a double propuse, if you can get the dupont or Kolon Dry film Resist, you can create you own photosensitive boards with this iron.
so you can switch from laser transer to Photoresist with  almost the same hardware
another good thing is that this irons are no so expensive like some professional laminators.
http://www.ikolon.com/eng/films/dry_film/dry_film_intro.html (http://www.ikolon.com/eng/films/dry_film/dry_film_intro.html)
http://tyvek.com.mx/Imaging_Materials/en_US/products/dryfilmPhotoresist/index.html (http://tyvek.com.mx/Imaging_Materials/en_US/products/dryfilmPhotoresist/index.html)

Hope this helps
Cheers
PS i almost forget... you can make your solder mask with Dry film photoresist too!  ;)

I use toner transfer using normal Glossy Paper (most people would like to use a photo gloss paper. But using them increases your cost per board.) But with Glossy Paper the heat transfer time is increased. About 5-6 minutes under an electric iron with some pressure using your hands is sufficient.

ya know ole,  I used this method before, but its unfortunate that I cannot get it right.  Tshirt are made of flexible compressable material, so when you press them they will flatten and levels. 
When using this method on PCB, I found that PCBs never is 100% level, and it cannot compress on the high/low points, thus the toner were never transferred 100%.
The difference is in micron but this made a lot of difference.


You must have special method to make the PCB ultra smooth and level..  I like to try it.. please share.

Hiyas Parmin:
i always put a soft and heavy cardboard (like some dense cartoon box material)  over the PCB and with the pressure and heat amount that the iron can give to the assembly i had no problems with the transfered image, i always smooth the sides of the PCB with sandpaper to get a little angle ( like a knife sharp) then i put the laser printout and then the cardboard , and press about a minute , then i release and let go cold, and soak it with a bit warm water, when i can see the image trough the paper i start to remove it gently.
the heat flows really nice over the cartoon and hit the PCB correctly
cheers

Hi Ole
T I have tried the cardboard method I even tried heat sink foams, cloth, High density closed and/or open celled foam etc of various thickness still it doesn't work well:

I think I am missing something important somewhere.

What is the temparature of iron or laminator?
Is critical temperature?

The iron i use is somewhat old so i don't have a real temperature setting, i put the knob to 180 ( in theory should be 180 C) and let the press down for a minute, i sand the board with a very fine metal sand paper ( gently!!) and then i clean it with acetone (before the transfer process, of course  ;) ).
Here you have a image before etching
Cheers

BTW i find useless to try a QTFP64 + footprint with the toner method cause the pads appear bridged, same for another fine pitch packs.

I usually use a 60gr paper with a laser jet printer. and then oily on it with sunflowerseed oil until the paper become transparance, then next process follow the step that already post.

hi OleRuffo,
have you a video of your réalisation of PCB with TTF?
I have some deformation, the line is not parallele!!
Wath is your pression (press down)?

Hi Fr5:
Sorry i have no videos about the process, in fact right now I'm working with a very dense PCB so its not suitable for this technique ( not even for photo resist)  4 layers, some QTFP 80-140 pins and some other fine pitch parts that i had send to produce in a professional facility).
the press pressure is unique (Can't be controlled), just a handle that one pull down until lock, i have no idea how much is too much. once i finish my actual work i will try to post some images of the whole thing.  ;)
About the deformation...maybe, just maybe your press don't push evenly, or the level mechanism make a slight lateral movement? just an idea  ???
Cheers

Hi guys.  I thought I would chime in here with a few thoughts.
I print using an Epson R200 printer, using precision A4 Inkjet film and I always get good results.
I use JetStar Premium A4 10 sheet pack from http://www.megauk.com/artwork_films.php
Also photo boards from same supplier http://www.megauk.com/pcb_laminates.php
I have a 4 tube UV box (from RS components)
Developer is Seno Liquid Dev conc 1Ltr for 10Ltr - 20ltrs  http://www.megauk.com/pcb_chemicals.php
I use this 1.1KG Fine Etch Crystals for 5 Ltrs for etching in a bubble etching tank, also from same company.
I make a lot of pcb's with fine pitch IC's and have no problems, many of which are 2 oz copper.
Using this method I can re-use the artwork over and over again.

I never was a fan of the iron-on method, or using laser printers, the resolution on the R200 is much higher at 5760 dpi.

Steve

Hello.

In this web site will see how to make a machine to laminate printed circuit boards using an old laser printer, using precione rollers and heating lamp.
Link: http://blog.opcode.com.br/dispositivos-diversos/laminadora-pci/ (http://blog.opcode.com.br/dispositivos-diversos/laminadora-pci/)

Video: http://www.youtube.com/watch?v=-61zAe_zgUg (http://www.youtube.com/watch?v=-61zAe_zgUg)

  enjoy.  ;D

I have spent much time (and money) to make PCB with acid, film, etc
Now I find more convenient a (Italian) company that make prototypes of pcb
example:
 2 PCB   40x40 mm  Dual layer    28 €

do it yourself for less than 5€ is best for me, 28 € is a lot of money :(

Ok Ok Mario

I agree with you

In past  I made   own  cs, but I do not say how many dresses  damaged  from acid
and then  considering  the lost time, drilling, manual jumping vias, etc

actually with more few  euros  I have a very professional result

Step by step instructions along with pics. Hope this helps somebody.

http://www.riccibitti.com/pcb/pcb.htm (http://www.riccibitti.com/pcb/pcb.htm)

I found that making the kit required for photoresist-style PCB making was part of the fun. I suppose it depends on whether one is mostly a hobbyist or serious student/professional though. I've always been a hobbyist, so the extra time required to make my own boards and fact that I can do everything myself, and save money, is appropriate. If I wanted to publish anything I would probably have a board made.

Anyway, I've tried most of the available methods and find making a transparency with a laser printer and using a pre-sensitized board the best for fine pitch. I can reliably do down to 0.5mm tqfp double sided. I've used Brother, Oki and now an HP laserjet printer, all with good results on laserstar film. I made a double-sided UV exposure box from thin wood and a heated bubble etching tank from acrylic sheet, an aquarium air pump and a chain of power resistors in heat shrink tubing.

For etching I much prefer ammonium persulphate to ferric chloride. It's much cleaner and easier to see how etching is progressing.

For larger scale stuff, i.e. nothing smaller than 0.1" (maybe with a single trace between i.c. pins) then I print onto glossy photo paper and do the iron-it-on and soak-it-off trick with an iron. That works OK, but not perfectly.

I did buy a high temperature (180 Celcius) laminater that can take 1.6mm thick material, but it takes so many passes through that it's quicker to just use the clothes iron!

Plated though holes are possible by using PCB repair kits like the Copperset tubes. A bit fiddly to do but with care they work perfectly. These days I stick to SMD parts as much as I can though; it's much easier.

Here is my one......
I ve use "Readers Digest" magazine Paper  ;D
Its work very well for me  :D

I'm using the sticker paper backing......the yellow one and I get amazing result!


(http://i82.photobucket.com/albums/j249/Rhonn_2006/Image341.jpg)
(http://i82.photobucket.com/albums/j249/Rhonn_2006/Image340.jpg)
(http://i82.photobucket.com/albums/j249/Rhonn_2006/Image343.jpg)
(http://i82.photobucket.com/albums/j249/Rhonn_2006/Image346.jpg)

Photoreist is the better, but not fast and more expensive. Toner transfer using photo paper (for ex. hp glossy is economic and work very well) is good too, but less resolution and maybe hard to make a good pcd for smd devices. I usually use toner transfer for double layer, photoresist for single layer. To etching a mix of 20% solution HCl  and 9% solution H2O2, it's very fast, clean and economic

I already tried with dry-film (from ebay) and the toner transfer method. I use a cheap Scotch laminator (TL901) that I bought from Amazon.

Both works fine, as soon as you learn how to work with then. For instance, with this laminator and the transfer method, printing with a Xerox printer, I have to pass the board about 20 to 25 times in the laminator to guarantee that the toner will fully transfer to the board.

On the other hand, I had some problems with bubbles when applying the dry-film. But carefully working with it and the bubbles were gone.

Definitively the dry-film have a better resolution.

old topic seen this  no heat toner transfer
https://youtu.be/cVhSCEPINpM

Good method! I didn't know about it!

I'm doing some experiments with the UV-curable paint usually used for protecting PCB tracks (https://www.youtube.com/watch?v=wvU2yyfH-XE) for making a PCB  by using a cheap UV oven (https://www.youtube.com/watch?v=3QDpAUkfjY8).  This seem to work no so bad but I need further tests. In alternative the Heat tone trasfer with laser-printed ink on copper works very well, maily when I use magazine paper.

I always use UV PCB method. you can get the highest quality in that method. also all methods (Except milling) require some sort of Ferric-chloride or similar for etching. So there is no reason why people don't use this method.

you can make your own exposure box using old scanner

I think most nail polish removers are acetone based. Apparently there are non-acetone based ones that use methyl acetate (easier on skin?). The one in the video does not say "non-acetone", so I'm guessing it is acetone based.

Jumping into this topic once more time :)
Lately I have been getting PERFECT results by using my laser engraver.

The technique is very simple:
1. coat the blank PCB with engineering blue (dykem) or cheap spray paint from dollar store   - try to get thin and even coating, the thinner the better)
2. Use a laser engraver to burn the paint off the part you wish to etch (I use either my CO2 but you can also use a cheap 10 watt diode engraving machine)
3. etch the exposed board.

I managed to get quite consistent 0.1mm lines and separation with this method with dykem coating.

Cheers - happy trying.

I opted for a mini CNC from China many years ago thinking that it would be the best solution. Ever since that time, I have been working to make that solution work but I haven't lost my hope in any way.

I have a desktop 3018 and can get consistent, clean results. what trouble do you have?

1) wash your board and clean it
2) print your pcb in glass paper
3) put it your paper on board and with ironning it
4) next put ypur board nad paper to cold water
5) after 2 or 3 minute dig your paper slowly but just becarefull :)
6) after with nail clean it very carefully
7) put it in acid and shake it
8) when it finished you can pick up your board and wash it
9) then you must drills the pad but carefull
10) the last step solderring the board

I have used just about every method here, some with great results. I always used chemical tinning afterwards for best results. But when I started using 100 pin FQP and other surface mount stuff you cannot fault Press 'n Peel. I generally print the pcb centered on a sheet of paper then cut a piece of film about 20mm larger all round. I use a laser label or two to hold the film to the paper (centered over the print) then print on the laser printer. The results are very good if you iron it correctly. I always use fine wet and dry paper, it gives a far better finish than wire wool etc. especially if you are goin to plate the tracks.

In all fairness, thinking of building pcbs at home in 2022 is not a very wise thing, especially when it comes to pcbs with high-density pin density smd components.
There are various Chinese services that produce excellent pcbs at very low prices in 48 hours, e.g. from JLCPCB 5 pcb 100x100 mm cost only 2 Euro, made in double-sided, solder and silk-screen printing, with tracks and insulation up to 6 mil, pcb contouring for any shape.

Check this: https://www.instructables.com/Photoresist-Dry-Film-a-New-Method-of-Applying-It-t/
and this: https://hackaday.com/2021/12/28/uv-printing-pcbs/
Note: With a newer 4K screen models it is not necessary to remove the glass, look for 35x35 um pixel size 4k mono lcd screen. Larger sizes screens are 50x50 um pixel sizes

Making pcbs at home is the fastest way to get from idea to prototype testing, or proof of concept, before your inspiration dries up waiting from your pretty pcb from China. Some are happy with a simulator until reality hits them.

From the moment I send the gerbers to the service in China to when I receive the pcbs, on average only 5 days pass.
I am not a youngster and in the past I have made many pcbs by myself, starting with the use of the appropriate inks with nib and stencil, with the transfers, ending with the photoengraving using film and UV, ending with laser printing on paper and hot transfer on copper.
The problem is always the same, very small tracks never look good, the double face with metallic vias is a utopia, especially if you work with high density smd.
Obviously, each of us is free to choose the path to follow, but not taking advantage of the solutions that technology makes available to us easily at low costs is not a wise thing.

Yes, companies such as PCGOGO supply PCB's quicjkly and cheaply. But when you need to make a small breakout board on a Friday to mount your lastest smd device for that urgent project.... It is better to at least have the ability to do so considering it taks about 30 miniutes.

DIY vs PCB houses, it all comes to TIME. How many days from your first pcb design to your third pcb's revision? DIY approach will take hours or a couple of days, PCB house will take several weeks. COST is less with the PCB house approach, and QUALITY: don't even have a talk about it.
If you want your prototype to look professional, then send the pcb design files to the PCB house only after you have corrected all the design problems on the DIY boards, it saves weeks of waiting time until the end of project.

Yes, this.

Of course we know PCB houses can be cheap and for some people a couple of days is *fast*..  ::) but for me, I like to prototype ideas quickly and iterate through them very quickly.. so with DIY, I can do that in one *afternoon* and it is cheap as well. So DIY PCB ** Definitely ** has  place in the shop even in 2022 and can't be beat for speed.

and then .... after I get proto circuits working well enough, I might polish it up and do a more complex prototype with a Chinese PCB.

I think people that advise to get PCB's from China don't understand that nothing beats something that is done by yourself.

Because:
1. It is deeply satisfying
2. As already told it allows a much faster process to get a working prototype.

Obviously this is a real market since there are companies that make equipment's that allow having PCB's done in the office (at home).

Besides. The OP question imply that it is about something belonging to DIY area.

Here I am going to enumerate all the DIY methods of making PCB's that I am aware of.

1. Toner transfer using a laser printed PCB pattern on a substrate (either paper - IKEA catalog works best :) or vinyl).
The limitations of this method is that it require uniform heat/uniform pressure and good quality toner, in order to get the best results. And very good results can be obtained without much bother.
a) The transfer is done by applying heat. Some use an household iron but the best results (impeccable results for as low as 7 mils trace width, or less) is by using a laminator modified to allow the thickness of the PCB. When using heat, the used temperature depends of the kind of toner that is used. About 180°C for HP toner and more (up until 205°C) for Brother, Kyocera, Xerox printers.

Pay attention to how much toner you use when printing. It is desired to have as much as possible (set in the printer settings) but once you get to under 10mils traces you need to be careful because too much toner will be pushed to the sides and may create short-circuits.

a2) Some use professional toner transfer paper (like the one from Pulsar) but I never had the need to use it, not when the Ikea catalog sheets works so great (100% transfer when used with a HP LaserJet 1022 with original toner and transferred at 190°C using a laminator - I have this one: https://www.aliexpress.com/item/32866074378.html).

b) Some do transfer the PCB pattern from the laser-printed paper using acetone. They wet the paper with acetone (or the PCB laminate, or both) and then the sheet of paper (vinyl) is pressed onto the PCB laminate until the acetone evaporate and the toner is transferred.

Due of limitations of how the laser printing is done, there may be a need for a post-process step involving a so-called "toner blackener" that will be sprayed over the printed PCB pattern to fuse together the toner and remove small spaces between dots. Here are used some commercial sprays (like Takter 330) or simply spraying "white spirit" solvent (stink) over the paper that holds the PCB pattern.

After transfer you need to remove the paper substrate (vinyl is removed much easier) by immersion in moderate-hot water (with a bit of soap). Clean the traces (especially between them) of the residual paper or it may create issues when etching.

After etching the toner can be removed by using acetone.

2. UV transfer
This is the so-called professional way to make PCB's, it is the most involved and will take a lot of time (about 2 hours from start to the end results, etched PCB).
The limitations of this method are that you need a perfect printed mask, any imperfections are transferred to the PCB.
a) positive transfer - means that what you print on the film mask (the opaque regions) is what you get on the PCB laminate after UV exposure. All the UV sensitive stuff that is exposed to UV light will be softened and removed after the developing step.
b) negative transfer - using the negative photosensitive UV film  found on Aliexpress, what you print and is opaque on the printed film will be removed after etching. This means that everything touched by the UV light will be hardened (will survive to the developing step) and all that is hidden from the light will be removed after the developing step.

The steps are:
 - print (laser or inkjet) onto a transparent medium. If using laser, the heat will deform slightly the film if using acetate transparent sheet. Try to compensate when printing (Sprint Layout software has a nice GUI but it has issues when loading Gerber files generated by some software like Altium - the ground plane is covering everything). Some laser print on tracing paper but I found that sometime the toner will not stick correctly and leave some gaps which are annoying because then the PCB needs corrections.

If using inkjet, it require the usage of pigment ink (not dye inks) to get the required degree of opaqueness. Some print them in double and overlap them one over the other to increase de opacity. Some fill all the colors with black ink (I do that).
- clean the PCB laminate. I start by using fine sandpaper to promote better adhesion. After that use some Unilever CIF (household cleaning stuff, the one with bleach and crystals - works best) to remove the oxides and greases. Fingers have a lot of grease on them so if you know you can't do without, use gloves.

Also, when printing with the laser, it will benefit if using a toner density spray (like Takter 330 or the like) it increases a lot the opacity (no longer the need to print in double the pattern).
- laminate the photosensitive film if using the negative transfer. This can be done dry or wet. The dry method involved applying the UV-film sheet to a the PCB using a laminator set at about 108°C. Sometime the film is sticky (especially if old) and for larger PCB patterns the curvature (it come rolled) can get in the way because once it touch itself (after removing the thin layer that exposes the sticky side) it glue to itself and you need to repeat the process.

The wet method involves spraying a mist of distilled water (not too much) over the cleaned PCB laminate followed by applying the film by hand. It gives you some time to get it right, you can remove the already applied film a few times in order to make sure that there are no bubbles of air caught here and there. Then starting from the center with gentle moves, press the water out to the sides. Once the film is applied and there are no bubbles, put it through the laminator (108°C) a few times.

I find that it is better to do this laminating step a few more times after I decide I should be over.

When using positive transfer either you get pre-made PCB sensitized o UV laminates or you need to spray yourself the stuff onto a PCB laminate by using special sprays. This is messy and it also is hard to get a homogeneous layer which matter when doing the exposure.
- UV exposure - apply the printed film (UV mask) over the sensitized PCB laminate, the printed part should be oriented toward the PCB, toward the copper sheet. This way the mask is as close to the sensitive UV film and therefore minimize the light spread under the mask. When using the Chinese photosensitive film, it is better not to overexpose, it is actually better to slightly underexpose. When exposing using an A4 board covered with one of those 5 meter UV LED strip - Aliexpress/Ebay - I found that about 20 seconds exposure is OK.

I say slight underexposure because after exposure, you need to be patient and wait about 10 minutes for the polymerizing process to finish. Leave the exposed board covered for about 10 minutes until the next step and you are good to go.

- develop the exposed PCB - you may need to remove a thin sheet of plastic over the now exposed PCB if you used the negative photosensitive film. For the negative film a solution of 9 grams of sodium carbonate (warning: not the sodium bicarbonate you get in the kitchen) to 1 liter of water will do the trick. One can make sodium carbonate from sodium bicarbonate by heating it in the oven for a time. Look on the YouTube/Internet for the process (https://www.youtube.com/watch?v=cpGEc-pLXN4).

For the positive film PCB's a 10g of sodium hidroxide (NaOH) to one liter of water should be enough. Others use the sodium metasilicate pentahydrate (About 100 grams to one liter of water from what I've read but I never used it).

Use a brush to speed up the process (if you are lazy like me and don't want to heat the solution to about 30°C as it is recommended) and brush continuously to remove the gunk that is forming when the photosensitive stuff is attacked by the developer solution) and exposing the lower layers.

When you see that all is developed insist for another minute or so to make sure that the transparent stuff that may still be there is removed. It is interesting how a very very thin layer can still protect the copper, of course it depends on the kind of etching solution you are using.
- etch the PCB board using chemical reagents

3. Direct laser printing
You can use:
- A 3D printer with a laser head
- a CNC machine with a lser head
- dedicated laser cutter machine with a laser head, the ones without an enclosure

Make sure you have a UV sensitized PCB laminate. I will talk about one covered with negative photosensitive film (made like indicated above) but you can adapt this for the per-sensitized positive PCB laminates.
Make sure you use a laser head that is not too powerful. The more powerful Laser LED diodes do not have a round dot but a square or worse, a rectangle. The 400mW Laser diodes should be OK.

Create a GCode that will cover the areas that will have to be sensitized by the laser light (the traces, pads, regions etc).
This can be done by either:
- rasterize a picture (BMP, JPG, PNG) at real size of the PCB (check LightBurn software).
- make sure you focus the laser beam the best you can and get an idea of how wide is the beam dot
- vectorize the Gerber features using software like Vectric or FlatCAM (beta version has those features) using a suitable feedrate and the dot dimension as tool width

The steps:
- expose the PCB pattern on the PCB UV-sensitized laminate
- develop the PCB like above
- etch the PCB board using chemical reagents
Or:
- paint the PCB with normal black paint and let it dry
- use a more powerful laser beam to create isolation paths inside the paint by burning the paint where the laser beam touches the PCB laminated. It may need a slower feedrate to allow for cutting into the paint.
- etch the PCB using chemical reagents.
Note: this can be used to create soldermasks too.


4. Direct printing using a modified printer.
This require to mechanically modify a printer such that the "paper" will travel in a linear way. Some modified a laser printer and made it to print toner directly on the PCB laminate.
Some others modified inkjet printers using a special ink that acted as a resist when etching (some yellow ink is reported to work).

There is also a UV ink that can be printed by Epson inkjet printers (they use a reusable head with piezo elements) and then can be hardened by UV exposure. This needs to be looked up as to how high the PH needs to be for removal of the stuff after etching

5. Use a CNC machine (or 3D printer) to guide a marker with a suitable tip diameter and plot the PCB pattern onto a PCB laminate. The CNC GCode can be obtained from FlatCAM (using the so-called Paint functionality) or from the Inkscape GCode plugin.

6. Mechanical isolation (aka scratching). This is done by scratching the copper layer and creating islands of copper to act as traces and pads.
The limitations are that it creates dangerous dust of glass particles that are so fine that can cross the blood barrier in the lungs and get into the blood). It is also a very long (and boring) process but the results can be unexpectedly good. The up side is that it does not involve long steps and chemicals.

The most primitive way is to manually scratch the copper layer using a sharp tool (either a needle of a knife/cutter).
The advanced way is to use a CNC machine (3D printer) to actually go around and isolate each trace using special milling bits (V-bits or pyramid-shape bits or the most advanced and expensive spiral milling bits with diameters of 0.1mm or greater).

To get the GCode to guide the milling bit you can use the following software:
- venerable CopperCAM (paid software)
- Inkscape plugin
- AntFarm new software: https://github.com/TheAntTeam/TheAntFarm
- FlatCAM: https://bitbucket.org/jpcgt/flatcam/downloads/

PS:
When doing chemical etching some do it using one of the following chemicals to remove the excess copper:
- ferric chloride - nasty stuff, stains anything it touches and in time it degrades. Needs a bit of temperature to accelerate the process and shaking (air bubble mixing) helps a lot.
- sodium persulphate, amonium persulphate - slow process, the stuff is not stable for long after it is mixed in water (it comes as a solid), only for a few days. Needs about 50°C temperature or the process is simply to slow.
- a mix of hydrochloric acid and peroxide (hydrogen peroxide) - fast process, needs to be slowed down if you have fine PCB features by diluting with water. I use (when in hurry) about 2 part hydrochoric acid, 2part peroxide (depending on how concentrated is the stuff, for 3% found in pharmacy use 2 parts) and 3 or more parts ordinary water.
You see if you need more peroxide if the copper is not turning to brown color immediately after immersion in the solution of the PCB laminate in the exposed copper areas. Add more peroxide.
If the copper is turning brown color but you don't see bubbles of gas developing then add more acid. Slowly, do not splash. Use glasses or you might remain without eyesight,
- some use nitric acid . Nasty stuff, I still have a healed mark of a small hole in my left arm from since I played with it. Nasty and toxic fumes, burns almost anything except aluminum.
- BEST: use the copper chloride. Requires maintenance (hydrochloric acid and peroxide added from time to time) but you can basically use it forever and it is gentle with the underside etch.

Ok, I hope I covered everything. Took a while to write this huge post, I hope it will help someone.

the best method for me today would be to etch directly the copper using a 20-30W fiber laser
fast and no chemical, only need a well ventilated place, ... and $2000 !
otherwise I wouldn't bother and use a cheap pcb company, or if I need double sided complex board.

https://www.youtube.com/watch?v=-dQzufH8FEQ
https://www.youtube.com/watch?v=CU7iKe2trIw

you cannot really etch copper with a fiber laser, the absorbtion rate for copper at this this wavelength (around 1000nm) is about 8%, 92% of the incoming energy is reflected.
I have a 15W fiber laser, it works well with aluminum, steel, plastics etc, but with copper it doesn't work at all. It works well with the pcb-epoxy though, once you make it through the copper everything under it is burned immediately.

so all the movies on youtube showing a 20w fiber laser burning copper on a pcb are fake ?

Yes.
It needs a lot more power.


Best Regards

It depends, if the 20 W are the real optical power it is possible, if they are the laser input power it is not possible to engrave the copper for a pcb.
A real 20W out fiber laser requires over 80W input, costs no less than 4000-5000E.

https://youtu.be/RudStbSApdE

I used to use chemicals tried all methods but messy so now I’ve got my own CNC machine which I use to make simple one off projects, the hardest part is the via’s on double sided boards, I’ve even got the correct tool with copper rivets which weren’t cheap and it caught me out once trying to trace a fault which was caused by one of them so still ended up putting a blob of solder over them to make sure connections are good. This method is still time consuming  and soldering SMD parts between .4mm tracks without tracking can be tricky but good to prove your design if you wanted more then one off.
 But now I just use JLPCB fast service and good quality, just waiting for my last order which consist of 3 projects 10 boards for each one and only cost me 35gbp including postage. When I’m working on a project there’s no rush or deadline to meet.

So for me now days get them sourced out not worth the hassle or mess with chemicals

as I mentioned in my post I have a 15W fiber laser, and that is of course optical output power. Laser specs are always output power, never input.
And my 15W laser does almost nothing on copper.
I can imagine a fiber laser with a lower wavelength would be good, but I don't think you can get one of those for $5000

on a fiber laser, it seems that the lens size must be paires with the laser power
a 20W laser needs a 100mmx100mm working area (= lens foical) for enough power
a 30W laser can go with a 200mm lens
if you have a 15W laser and a 300mm lens it could be normal that nothing happens on copper ?

ps: as I dont have (yet) a fiber laser, these are only thought I have after surfing on the subject for some times ...

no, the lens diameter has nothing to do with the laser power, it only defines the scan area.
The laser beam is only several mm, it doesn't matter how big the lens is.
My laser has a 75mm diameter lens, focal lenght is about 180mm.

Yup. I've played a bit on 6K resolution SLA printer and the results seem promising.
Considering that cost of hi-res SLA printers are dropping significantly I suppose that one could even gut two printers to make a "sandwich" and expose double sided PCB at once.

The only downside is that at this point one has to convert PCB layout to .stl files in order to use original SLA printer hardware.

Seems like that would be a great export addition to consumer layout software, or even better would be if someone wrote a stand-alone gerber to .stl converter for just this purpose, that is if this technique takes off and I can certainly see the potential for this to take off...  I could even see spin-off PCB exposing machines made for the purpose, if all you need is the LCD screen, UV lights, and a plate of glass in a box with minimal software to run the LCD and UV lights vs the extra motion hardware/software in the printer it would significantly cut cost of a purpose made machine...  Even 8K LCDs are affordable nowadays...

In my case I need to make PCB's that sometime might be as big as an A4 sheet so the current 6K or 8K SLA printers with such a size are still way too expensive.
But the use of a SLA printer made me think if it will not be an idea to buy a high resolution 13" or 14" display, take the light source away and replace it with UV LED strips.

Unfortunately I see two issues:
- one is that the glass of the screen might be made specifically to block UV radiation which is harmful. Might be.... although the white LED's are not supposed to emit UV, so who knows if the glass is truly blocking the UV light
- second is that when displaying the white on the LCD there are actually sub-pixels involved (R,G,B) and that might create some issues. On the other hand the photosensitive film do polymerize in vicinity of the exposed area, not much but it does, so for high density displays it might just work. 

That is why most of these printers have now moved to monochrome LCDs...

The biggest issue as you get bigger displays is the pixel size, even at 8K a 13" screen likely isn't going to be a small enough pixel size to get high enough resolution...


To try this I would remove the actual LCD, use regular plate glass, thinner the better and a proper UV backlight.

No all of the models use a glass over the LCD screen that is why, so far, resin vat leakage most often requires LCD display replacement. The printers are made to transmit as much UV light  as possible to the resin vat, so no UV light blocking material is used in the light path. The plastic cover and a safety switch are supposed to protect the user's eyes but, most importantly, the user's common sense should be required for safety (not to bypass the cover switch for example)

The 405nm reflector-based UV used in most consumer DLP printers, is arguably no more harmful than sunlight unless you are some dolt that is staring straight into it for extended periods of time.  I'm not advocating disabling the cover switch and running without, as the cover also provides dust protection, but running a consumer DLP resin printer less cover is not all that dangerous...  The commercial SLA printers running 355nm lasers are of course much more dangerous as it's highly focused more damaging wavelength, assuming it was directed at your eyes...

It seems that one can buy relatively cheap 8.9 inch 4K mono screen with HDMI input.
In that case no gerber to stl conversion would be required.
https://www.aliexpress.com/item/1005003493405410.html (https://www.aliexpress.com/item/1005003493405410.html)

I wonder how much of a nightmare scaling would be over HMDI to that display across devices...

Check the specs of the mono display, you want very high contrast ratio. Check also that the Hdmi to MIPI adapter has been programmed for that particular display. The initialization of the MIPI displays is not a standard and the chosen controller has to be programmed to initialize them.

Nothing that cannot be calibrated with a few iterations. Sprint Layout can, for example, scale on X and Y axis a Gerber so it can adjust the print result therefore making it useful for compensation of such LCD presenting scaling errors.

I can definitely testify that fiber laser can make PCB easily.
On my 20W machine I have etched out copper many times and all is good.

The lens focal length definitely have effect on the power transmitted.
With 50mm focal length, I can even cut the boards (very stinky fumes) to odd shapes if required.

Here's my method:

CNC some holes for top & bottom acetate alignment. 
Laser print on acetate then UV method for etching with FeCl3
Tin plate (why not, it's an easy step). 
Sometimes dry film solder resist, depending on pitch. 
CNC for holes and board outline (CNC saves a lot of time, just generate the gcode and let it run). 
Add copper rivets for thru-holes
Generate the paste layer to deposit solder on the rivets, to guarantee a good connection (I have been caught out with a bad rivet to PCB connection in the past). 
Silhouette portrait for stencil creation with mylar sheets. 
Place parts by hand. 
Home-made reflow oven with controleo2. 

Some of my protos have even ended up being tested in a nuclear power station!  (Nothing critical I was assured). 

Whats your finest trace and space geometry sizes you can reliably achieve with this method?
What laser printer model works for you with acetate?
TIA

The first printer brand was HP (model unknown) that gave good results, really dark prints. 
I've tried a few samsung printers and found they don't put enough toner on the page, so I would not recommend samsung. 
I now have an HP laserjet pro M201dw that works well with these LaserStar transparencies:
https://uk.rs-online.com/web/p/transparency-film/2866773

I also use Toner Density spray from Reichelt:
https://www.reichelt.com/de/en/toner-compressor-lf-a-400-ml-tvd-lf-a-p89770.html?r=1
Just spray it directly onto the printed page and leave to evaporate, it effectively darkens the print and reduces the risk of pinholes. 

I've made boards with 56 pin QFN in 8x8mm package and ground pad. 
Another breakout board used a samtec connector like this:
http://suddendocs.samtec.com/prints/qth-xxx-xx-x-d-xxx-footprint.pdf

7mil clearance and 8mil traces. 
For PCBs, I use either CIF or Mega Microtrak.