Exposing, Developing, Etching and Drilling PCBs - My (Current) Way
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- เผยแพร่เมื่อ 18 พ.ค. 2024
- Me making a printed circuit board: There’s room for improvement …
↓↓↓ Complete description, time index and links below ↓↓↓
Note that this is not a tutorial. It’s just a video showing my current process of making single layer PCBs. If it entertains you - good. If you learn something - even better. If you have suggestions for improvements - the best possible outcome (for me)!
Anyway, the video covers everything from the finished PCB design to a PCB ready for soldering. In real time it took me a little less than two hours (including a minor hiccup). For your convenience I’ve condensed it down to 42 minutes.
►Intro
00:00 Intro - how to get from raw PCB material and a design to a PCB ready for soldering
►Exposure Mask
00:31 Printing - two copies on a laser printer (non-mirrored, toner will touch PCB)
01:00 Spraying - the copies with density spray to improve - well - density
01:24 Cutting - the two copies to size, one a little smaller than the other
02:12 Aligning - the two copies on top of each other
►PCB Raw Material
03:31 Cutting - on the table saw with a diamond coated blade
►Expose & Develop
06:09 Aligning - exposure mask and PCB material
07:38 Exposing - the PCB material in my UV exposure unit
09:00 Mixing - the developer solution from sodium hydroxide (caustic soda, lye)
11:15 Developing (i) - failed, photoresist didn’t come off as planned
16:15 Developing (ii) - succeed, well it was good enough
►Etch
21:18 Mixing - the etching solution from sodium persulfate
23:01 Etching - the exposed and developed PCB material
►Expose & Develop Again
27:59 Exposing & developing - a second time to get the photo resist off
►Intermediate Result
30:55 Inspecting - the etched PCB
32:02 Reviewing - the PCB from the failed exposure & development
►Drill & Mill
33:16 Plan - for drilling and routing the PCB
33:56 0.8mm holes - drilled with diamond coated drill bit
34:38 1.0mm holes - drilled with diamond coated drill bit
34:53 1.2mm holes - drilled with diamond coated drill bit
35:01 1.5mm holes -drilled with diamond coated drill bit
35:26 1.2mm slots - drilled and milled with diamond coated drill bit
37:03 1.0mm slots - drilled and milled with diamond coated drill bit
37:39 Freehand 1.2 mm slot -because I forgot it in the PCB design
38:38 3.0mm holes - drilled with regular HSS drill bit
38:51 Unmarked 2.5mm holes - drilled using a paper template
►Coat
40:27 Spraying - the PCB with some flux/protection coating
►Wrap-Up
41:24 Inspecting - the finished PCB
42:00 Wrap-up - from design to PCB in under 2 hours
UV Exposure Unit Build • UV Exposure Unit Build
#robertssmorgasbord #diy #pcb #circuitboard #printedcircuitboard #board #etching #developing #drill #coating - วิทยาศาสตร์และเทคโนโลยี
That's a classy process you have there Robert! I used to use Kinsten pre-sensitized board (the green colored photoresist made it easy to see progress), cut to size with a drop saw, and printed inkjet transparencies wedged between two CD covers held with pegs, exposed with an ordinary fluorescent desk lamp, developed with dilute sodium hydroxide, etched with ferric chloride warmed up in a microwave oven. I usually left the photoresist in place to prevent tarnishing but it could be wiped off with IPA. Thankfully it was a very forgiving process and timing/temperature was not critical.
Thanks! For some reason Kinsten PCB material is not available here in Germany (saw it on amazon.com though). Would have loved to try it (after the trouble with the Bungard stuff). I etched my very first PCBs back in the day using ferric chloride. Meanwhile I really prefer sodium persulfate. OK, you got to control the temperature while etching, but it's so nice (fun) to have a clear etching solution and be able to continuously see what's happening ;-)
Nice drilling setup you've got there.
Thanks! I bought the stand and that drill primarily for drilling PCBs (though I do use the Proxxon IBS for other things too).
I love your videos! I just order a Proxxon table saw. You introduced them to me.
Thanks! And have fun with your saw!
Very nice work.
Thanks 😄
I love this, you're great. Thank you!
You're welcome! And thank you for the praise!
From what I can see your process definitely works quite well! Wish my boards looked like that, but I've never tried photoresist boards.
Believe me, photoresist is the way to go. I had a look at ink/toner transfer, milling etc. The only technique I think might be superior is printing an etch resistant ink directly onto the copper using an ink jet.
Thank you very much for your interesting video, it is similar to my system.
As someone do, i also tryed in the past spraying fotoresist, but without post-heating ... Spraying must be operated in a dust-free room, and so you have to breath dangerous vapours; and you can't do it outside, because there is too much light ( and wind with dust ). Also you have to do this job often, so to become more and more clever ...
You have to begin spraying outside the board, than cross the board itself and stop outside.
At the beginning and at the ending the spray-can sprinkles drops of any sort ...
Now i'm using pre-sensitive board, but i'll change to foto-sensitive film, i think it will be better.
As etching solution i use chloridric acid ( 10 % , used for cleaning toilets ) added with a bit of solution of hydrogen peroxide ( 3% = 10 vol. as used in hospital and also at home for disinfection of little wounds... ). The solution can't be stoked ( produces gas ) and also vapours of chlroridric acid which are dangerous and corrosive, so this solution is to be used outside, in a well ventilated area, and discarded at the end of the work. When etching it doesn't produce extra gas ( no bubbles ), also it's colorless, just becomes a bit green during copper etching.
I suggest - for every board - to change develop solution with fresh one. It's cost almost nothing, i use to prepare one liter of distilled water with 10 grams of NaOH ( caustic soda or sodium hydroxide ) and stock it for next boards. I DO NOT SUGGEST TO ANYBODY to make higher concentrations to diluite at need ... TOO MUCH DANGEROUS ! Use always safety goggles and don't let bits of NaOH around ... too much corrosive !
Just i have to congratulate with you about your safety instructions when using chemicals : safety is a must !
About printing master, i also used in the past - to get a darker "black" to stop ultraviolet light - to go on a photographyc process, using photographyc transparent film, to get a negative and then a positive master with a very dark black, using 1:1 contact print and relative chemicals.
I also see in the video you are using a Proxxon table saw, i have the little one, with 20 teeth blade; next i'll try the diamond blade ...
You're welcome! And thank you very much for the detailed description of your process. You can always learn from others! I do like the etching solution you're using - cheaper and easier to get than mine. But I'm living in a city on the sixth floor of an apartment building, and so going outside 'cause to vent off the chlorine gas is not really an option :-) Anyway, you should definitely try cutting your PCB material using a diamond coated blade, I always marvel on how easy that blade cuts through the PCBs.
Hi Robert. Excellent! Excellent! Excellent! It is the best detailled explanation I ever seem on TH-cam on the subject. One thing I would like you to comment on is this density enhansement product. Can you give a pointer to read more about it? Thank you again for all this knowledge you share. Regards, RJM
Hello René-Jean! Thank you so much for the praise! There was already a comment from Audiophile Vintage below who asked about the density spray. Unfortunately I don't have a link to a review of that stuff or something like that. So I will definitely make a video about it next time I print out a UV exposure mask. Though that might be a while. BTW the MCP4922 (and MCP4822) videos are on their way: 30.08.20 analog voltages from PWM, 13.09.20 MCP4XXX basics and 27.09.20 MCP4XXX details. Took me a while but now I've shot everything I need. And as always, you're welcome! Best Regards, Robert
May I ask if you have any recommendations for single sided PCB design? Thank you.
I'm using (and liking) DipTrace. But then, I'm very old school 😅 and basically avoiding everything that's running in a browser or requires an internet connection (basically all other PCB software nowadays). The free edition (300 pins, 2 layers) has been sufficient for all my purposes so far.
Amazing process. I bet the quality doesn't compare to the toner transfer. Even though I don't even master that... I just managed to do my first toner transfer PCB hahaha. I will sure try the foto resist as well... and now I have a great example to follow. Thank you for sharing.
You're welcome! I don't know about "amazing", it's just how I do my PCBs. Compared to toner transfer photoresist will enable you to etch thinner traces. So yes, go for it! And don't be discouraged if the first PCBs turn out less than optimal. It takes a while to tweak the parameters of the process for a specific setup (used UV source, photoresist material etc.).
I will try it pretty soon... waiting for the PCB to arrive )) Have an amazing Sunday.
@@dxexplorer Thank you, I had a nice Sunday! And good luck with your first photoresist PCBs!
Cool video :)
Thank you very much :-)
Nice video Robert, I've really enjoyed watching your process. I'm using Ferric Chloride and in the end tinning solution instead of flux spray. I never had a clue about High Densitiy Spray you are using. Are the results marginally better with it?
Thanks! To be honest the density spray is probably "snake oil". It does something, but not much. However, I bought it and so I'll use it until the can is empty ;-) Maybe I should make a video about the effect of that density spray ...
@@robertssmorgasbord that would be interesting. Density spay should seal plastic particles somehow according to datasheet. I wonder if it's mechanical or chemical process. Have you thought about mini CNC milling machine?
@@MartenElectric My best guess is the density spray is just a mix of solvents, evening out the toner on the transparency. But I will definitely make a video about that density spray (e.g. looking with the microscope at the changes) when I print out my next UV exposure masks (which might be while).
And I've though about building/buying a CNC milling machine quite often ;-) In fact that's how I got into TH-cam: I bought some linear guides from China to build one - they were total crap - I uploaded a review video to let steam off :-)
I heard of measure twice cut once, but you take it to a new level!
Are the failed boards waste, or could you clean it with aceton, sand it and try again?
😅 (the measure twice cut once thing). Anyway, I never tried to reuse a failed board. You probably could do it, but why go through all the hassle? A standard 100x160mm euro board (FR4 epoxy, coated with photo resist) costs me 3,15€.
I have a cutting printer that I use for graffiti stencils on transparent paper. I wonder if one could print a cut stencil, stick it the board, and spray over it leaving just the copper and then putting that through the etching process.
I theory yes. Though I see some problems there with "islands" falling out after cutting. And I'm skeptical how well a cutting printer will handle fine structures/traces (e.g. 0.5mm).
@@robertssmorgasbord Yes you're right. I'm going to stick with your guide and see how it goes. Just waiting for the products to arrive :) I do use JLPCB but it seems so useful to be able to mock and test the system IRL before committing to printing. Thank you for your time in teaching this.
@@JayJay-ki4mi I've also used JLCPCB in the past - it worked quite well (though I only uploaded a finished PCB layout from somebody else). I think you have to put a lot more work into a layout before you can submit it to a PCB manufacturer. Anyway, you're welcome 🙂
i used to make double sided pcb at home but i used spray photo resist much more consistant and sprayed freehand put in dark box standing up to let resist flow to bottom and try and do it in cool dry conditions.Leave it 24 hrs and then heat to 50 degrees c for 20 minutes to make sure all solvent is out.Then use ferric chloride at 25 degrees 10 mins job done.The secret is to get print as dark as possible your print looks much to light that will let u.v. get through and weaken the exsposure.I send to china now they do pcb cheaper than i can buy etchant.Bit of a job for testing as desighn is fixed before proper prototyping.
I never tried spray-on photoresist (or dry film photoresist for that matter). I'm getting my Bungard photoresist PCB material for 1.94 € (single sided epoxy FR2, 100 mm X 160 mm). Without the photoresist it costs the same. So I never felt motivated to put on the photoresist myself. But reading your comment I guess I have to try it one day. Anyway, before that I'll have to master the solder mask process ;-) And yes, the prints out of my Lexmark 410de are not very dark. That's the reason I'm using two on top of each other (which is not optimal). I'm always thinking about getting an ink-jet printer for that purpose ;-) And no, nowadays you can't beat the Chinese PCB manufactures price wise - as long as you're willing to choose the slowest shipping option ;-) And you certainly can't beat a professional PCB manufacturer quality and feature wise.
What is the drill and drill holder that you are using?
The drill is a Proxxon IBS/E (th-cam.com/video/LzeDN0omelc/w-d-xo.html) and the drill stand is a Proxxon Micromot MB 100 (several videos on my channel - I was not quite happy with the quality).
I like this video keep going 🤠 greeting from Morocco*°^
Thank you very much! And I will definitely keep going 😉
Why do you have isolation slots in your design? Is it for inserting something during assembly or you just do not trust the non-conductivity of the PCB board substrate material? Thanks
DIN EN IEC 60664-1:2022-07, respectively, VDE 0110-1:2022-07 requires a separation (without) slots of 6mm (worst case scenario) for 250VAC. If you use specific PCB materials AND put an isolating coating on top of everything you can go down to 1.5mm. Since I'm a bit paranoid about our 240VAC here in Germany, have no datasheet for my PCB material and don't use an isolating coating I opted to adhere to the 6mm and where that was impossible I added isolation slots.
Must you use the photo resist film under red light?
Nope, as long as there's no sunlight and you don't let it lying around unprotected for extended periods of time, it's fine. When I'm working with that stuff I'll block the windows nearby with some cardboard and shield the material with the lid of a tin can when I'm not actually handling it. That's more than sufficient. Remember, it needs three to four minutes of UV exposure (at least with my UV exposure unit). So it's much less sensitive than the photography stuff.
@@robertssmorgasbord Ok. Perfect!
Nice, but I think the photoresist must have changed quite a bit, probably something to do with health and safety (usually is !) or a bad batch, because I've never experienced development problems like yours...however great results, doubling up on the artwork is a good idea, and I have never seen those two sprays that you have, that was interesting too, despite the mess I prefer Ferric Chloride...great vid, cheers.
Thanks! Ah yes, the issue with the photoresist ... I do have a theory: I didn't bought that stuff from a big name distributor (like Digi-Key) but some "discount" outfit (Reichelt, Voelkner or Conrad - I don't remember which one). I can't imagine Bungard messing up that bad. But I can totally imagine the boxes with the PCB material sitting after delivery outside on some warehouse ramp for an extended period of time - with temperatures either well below freezing or well above 25°C (like 35°C). Both will probably mess up the material. Bungard writes something like "store cool, dry and in the dark" on their website (I have mine in the fridge at about 7°C). Ferric chloride or sodium persulfate - it doesn't really matter, as long as it eats away copper ;-) Regards, Robert
Whenever you can, send out your artwork to a film output company that does commercial printing. They can output film for you that is superior to transparency laser prints. you will get higher resolution and very dark density in the black areas making for an easier time. You tell the output company to do the films positive, right reading emulsion down.
Thanks for the tip! Laser printers are indeed not really suited for the job (hence two transparencies on top of each other - and I always thinking about buying an ink jet). Anyway, at least around here you'll be hard pressed to find a film output company that is willing to do a single ad hoc print for a reasonably price. To be honest, before I go down that route I'll probably send my layout to one of those cheap Chinese PCB manufacturers. The main reason I'm not doing that currently is turn around time. One or two hours after I finished my layout I have my PCB if I do it all inhouse.
@@robertssmorgasbordфотовывод печатных форм сейчас стал проблемой. Все полиграфисты перешли на прямое изготовление печатных форм, минуя пленки! А было очень хорошо! Дорожки 0.127 мм идеально получались!
@@user-vq4nw2du2r Спасибо за информацию! (Google Переводчик)
Never had much consistency with positive photoresist and caustic. I prefer negative acting dry film and soda ash.
Interesting! I can see why a negative photoresist might produce better results: Small "holes" in your exposure mask just produce small copper dots, which will be etched away from the sides. I really should try some positive photoresist some day.
At what temperature and concentration do you use the soda ash? How long does it take to etch a board? And isn't soda ash solution also caustic ;-)
Anyway, thank you very much for the input!
@@robertssmorgasbord 10g/litre sodium carbonate deca hydrate (super market washing soda) make up with Luke warm water say 30 - 35C for a 100 X 150 board with about 50% film to be removed use 500 ml, remove board and wash when solution is milky, use a fresh batch of solution and soft sponge to get film out of narrow clearances. Common brand is DuPont Riston, data sheet / instructions for use can be found on net. Development is 3-5 min depending on film to be desolved. High school chemistry is rusty but my recollection is caustic is a strong base where it is mostly free OH- anions whilst the CO3 -2 sets up an equilibrium between HCO3- and OH- by robbing a hydrogen atom from a passing by water molecule. The free OH- is less concentrated in a carbonate solution and prevents stripping it clean instantly. Dry film can be stripped with drain cleaner crystals in water as that is NaOH.
@@evabaroni6693 Thanks for the info! And you're right, it's not caustic. It's just mildly alkaline (pH values are between 10.9 and 11.6, depending on the concentration). My bad! BTW your high school chemistry is not rusty at all - it's certainly better than mine :-)
A much faster and cheaper etchant, is to combine 1-part Muriatic/hydrochloric-acid (36.5 gm/mol) to 3-parts hydrogen-peroxide (3%).
Make only enough to cover the board because it will degrade with time.
Neutralize with baking soda before discarding…
Thanks for the tip! I'll that when I used up my sodium persulfate.
Where you buy film sheet circuit? 🙏
Do you mean the laser transparencies or the photosensitive PCB material? The laser transparencies are just cheap, run of the mill transparencies for laser printers (search Amazon or eBay for "laser transparency film"). The PCB material I usually order from reichelt.de: www.reichelt.com/de/en/single-coated-pcbs-c7781.html?&search=bungard&nbc=1
@@robertssmorgasbord ok, thank you brother 😁👍, i search in eBay a laser transparencies
@@yasha2575 You're welcome!
Great video. Reasons that your first try didn't went well, can be that light you were using to expose it was not good enough, or the solution ate it too much, or the brush took off some of the photoresist while in NaOH, I skip touching it at all, when I see that clouds formed over the part I want developed, just move the container a bit, and move it to water, you can then literally wash it under a stream of water, and clean it with hands, when not in NaOH, it's very hard to scratch the photopositive foil, in NaOH, it's being a bit diluted, and under cold water it's hardly attached to the copper layer. When you were going through it with brush, it was already developed enough to etch with HCl + H2O2
Thanks! There could be indeed many reasons for the process to fail. But for me it's most of the time the age of the PCB material. I store it in a fridge all right, but some of that stuff is several years old. It still works (most of the time), but I have to remember to lengthen the UV exposure time.
@@robertssmorgasbord also the preparation should be done in the dark or under red light, as while handling it, it can get damaged, so you get dots on the POWER or GND layer when etching :) I had lot of stuff go to waste before I finally got the process right :D PS. instead of using transparent paper, I use baby oil with white paper method, no need for additional stuff
@@PipikaTV In my experience the photo positive PCBs are not that sensitive. The stuff I use needs several minutes of UV exposure. Usually I block out any sun light (cardboard over the window) and use some indirect LED lighting during the whole process. I'm also covering up the PCB material with the lid of a tin box in between. The little dots are more likely an artefact of my old laser printer. Anyway, I'll definitely try your regular paper and oil method.
What does the density spray do? Why do you use it?
Next Sunday I'll publish a video investigating exactly that question :-) great timing, isn't it? In short, the density spray is supposed to make the laser toner more dark / black / lightproof.
It actually dissolves the toner and allows it to flow; but it’s not a miracle-worker!
@@robertssmorgasbord Cool. Ok. Looking forward to it.
@@SpinStar1956 Ah, that explains the strong solvent smell. BTW today I'll be uploading a short video about just the density spray.
Which is better? 10 minutes or 1.5 minutes in the developer solution?
I'd say 2 minutes - with my PCB material and my developer solution - should be enough. If the photosensitive stuff is still sticking to the coper after 1 1/2 minutes I remove it nowadays with a soft brush. 10 minutes is definitely too long.
@@robertssmorgasbord Cool. Thanks.
@@Berghiker As always, you're welcome :-)
Wow, nice process. However, for such pcb it is much easier (and much less chemistry) to use thermotransfer method. Of course it is not ideal but for such fat traces it would be no problem.
Thanks! And your probably right. For the those traces thermotransfer would have been sufficient. However, I eventually want to get down to a trace width of 0.35mm / 0.0138'' with that process, enabling me to route traces between the pins of DIL packages.
I only use 1 layer but not reason I could not use 2, Next time i try it your way.... Yay
Good luck to you trying it my way :-)
This definitely brings back memories of the old radio shack kits to make a pcb board. Today I would probably just have it made in China. It’s cheap and very professional.
Yup, the Chines stuff is indeed affordable and looks good (see "Mini Mailbag: Breakout PCBs for HB100 Doppler Radar and MAX31855K Module (Reupload!)" th-cam.com/video/gH-aqvu_e1U/w-d-xo.html ). But the delivery time, at least to Europe, is a drag (you can get them faster, but then they're no longer affordable). So whenever technically possible I still like to make my own PCBs.
Have you made a PCB Etching Agitator? Surely you must have made one by now?
Actually, I just build one (laboratory shaker). First video of that series will be published next Sunday.
@@robertssmorgasbord Cool.
@@robertssmorgasbord Cool
@@Berghiker BTW I've published the first of the laboratory shaker videos: th-cam.com/play/PLwq-2MnM58FKSPDvq2neFdCp1wVfB9tSK.html ;-)
да зачерни тонер ацетоном и не парся, он у тебя там не должен быть запрещен, резать текстолит нужно ножницами по металлу, заготовку делать чуть больше чем нужно, обрезать после травления
Спасибо! Я попробую это в следующий раз.
First you put 6gr of caustic soda but you have to put 12gr.
12g surly is for a whole liter. I mixed up only 1/2 liter of development solution, hence I used only 6g.
Kann es nur bestätigen, die Qualität von Bungard sehr … variabel. Inkonstante Beschichtung und Empfindlichkeit, kann 25 sek brauchen kann aber auch 120 sek brauchen… Es geht auch mit halbtransparentes Papier. Es ist wesentlich günstiger als die Folie, zB Zweckform. Das mit dem Pinsel würde ich lassen, es kratzt die Beschichtung.
Kennst Du zufällig einen besseren Hersteller als Bungard? Ich kenne noch Proma und Rademacher.
Sounds like you have a swiss accent.
Actually, it's German ;-)
@@robertssmorgasbord Oh, ok. Sorry.
@@Berghiker No need to apologize! Germany, Austria and parts of Switzerland all speak German - or some variations thereof ;-)
I catch some secret what do you dont say positive filme...ha...ha....
Yeah, I kept that to myself :-)
You have stretched a 15 minutes video into a 42 minute video! Lots of talking and very little action.
Well, I tend to show in my videos every step and explain every detail, so they usually turn out to be quite long. I do understand that this format is not for everyone. I'm sure you'll find a lot of "How to make a PCB" videos on TH-cam 15 minutes or less that are more to your linking.
"Twice". Great! Now you talking like a South African. Not like an American. Two times ...🤣
I guess my English is all over the place ... it totally depends on what show / TH-cam channel I watched before shooting a video ;-)