 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
| HomeDiscussion GroupsElectronicsBasicsRepairDesignCADComponentsEquipmentElectrical Engineering ElectronicsKB.com Contact UsLink To UsSearch & Site Map |
Electronics Forum / Basics / June 2006Bubble etch tank - first board
Just made my first PCB using the bubble etch tank I made last weekend. Photos and associated ramblings at... http://lab.melodolic.com/index_PCBEtch.php This was done using the Press'N'Peel laser printed transfer film sold by Maplin in the UK. The process is about as simple as can be: print the pattern, heat the board-and-film sandwich, peel off the transfer, etch the board. It certainly seems to work, although I can't say my first result is pretty. That said, I may have over-etched somewhat, with the result that some of the resist was undercut. The etchant I used was the powdered Sodium Persulphate from Maplin (4ukp for enough to make a litre). Using it was no problem at all - only took a few seconds of stirring with a plastic rod to dissolve most of the powder, and a few seconds more in the tank with the air running sorted out the rest. I liked the fact that this stuff is almost as clear as water - very easy to see what was going on. Looking at the bottle, I notice that now has a slight blue tinge - something to do with the copper absorption? I got the temperature wrong when I mixed up the water, with the result that I had 35 Celsius rather than the 50 I was after. I put the lid on the tank and stuck it in the microwave - about 2 minutes at 1/2 to 3/4 power (in 20 second bursts with temp readings taken each time) brought it nicely up to 50 degrees. The aquarium thermometer was over-reading by 2-3 degrees compared to the digital thermometer. By the end of the etching session (say, 15 minutes in total), the tank thermometer showed a drop of about 4 degrees. I found that the board moved around quite a bit in the tank, and had settled such that some of it wasn't getting hit with the bubbles - after about three minutes, one half of the board was clear, while the other was still covered in copper. Jiggling it about about a bit had the remaining copper removed in another minute or so. I think I'll try some different basket designs, and maybe come up with a way of stopping boards sliding about. Overall, I'm very pleased, not simply because the Press'N'Peel seems to have worked at the first attempt, but because this is the first PCB I've ever made! :-) The home-brew bubble etch tank seems to work a treat - just need to come up with a better basket. Handling the tank was fine - tipping it up to empty the etchant into a container was easy, and the airstone retainer did its job perfectly.  SignatureMelodolic Spielberg > Just made my first PCB using the bubble etch tank I made last weekend. > Photos and associated ramblings at... [quoted text clipped - 9 lines] > That said, I may have over-etched somewhat, with the result that some of the > resist was undercut. What are you talking about! That board is beautiful! Congratulations on your first board! Michael D. > What are you talking about! That board is beautiful! > Congratulations on your first board! Thanks. :-) Drilled and populated it last night - amazingly, it worked first time! SignatureMelodolic Spielberg > Just made my first PCB using the bubble etch tank I made last weekend. > Photos and associated ramblings at... [quoted text clipped - 55 lines] > job > perfectly. You got an "A". Take your time my freind the first time is never easy,if you don't sucseed first time round addopt a different approach,maybe try dropping the tank temperature,using adifferent etchant or maybe change to a different etch resist,there is always hope,keep up the passion,from some one who cares,regards," roundle01" > Just made my first PCB using the bubble etch tank I made last weekend. > Photos and associated ramblings at... [quoted text clipped - 44 lines] > -- > Melodolic Spielberg Nice work! I think it's about time I got myself a bubble etch tank, been using a flat tray for 25 years now! Not much fun shaking that tray back and forth... Dave :) > Nice work! > I think it's about time I got myself a bubble etch tank, been using a > flat tray for 25 years now! Not much fun shaking that tray back and > forth... It was the prospect of tray wobbling that got me started with the tank. I originally went out to look at a possible mechanical means of wobbling the tray around (looked at motors and cogs in Maplin), when I saw the plastic box that was to become the tank. After that it was all just "that looks about right" on-the-hoof specification of parts as I wandered around the various shops (Maplin, pet shop, garden centre). Came together rather nicely, I reckon. :-) SignatureMelodolic Spielberg You can also use the press-n-peel blue to make a nice (black) silkscreen. Just make a second P-n-P "template" of your silk screen image...remember to mirror image it! Iron it on the top side of your PCB. Coat with some acrylic spray and presto. Do this BEFORE you drill otherwise you won't be ablt to iron the P-n-P onto the rougher drilled surface. Also... use a very small inner hole size for your vias. This will let your drill bit 'find' the center easily. The drill bit will of course open it up to the proper size. jj >> Nice work! >> I think it's about time I got myself a bubble etch tank, been using a [quoted text clipped - 8 lines] > various shops (Maplin, pet shop, garden centre). Came together rather > nicely, I reckon. :-) oh, almost forgot... You don't have to waste a whole sheet of P-n-P just to print a small board: 1) Print your image on plain paper first. 2) Cut a small piece of P-n-P that is slighly bigger (1") than that image. 3) Scotch tape the P-n-P (dull side up) onto the plain paper, tape it right over the printed image. Use ONLY one piece of tape along just the "leading edge" of the P-n-P otherwise you get a wrinkled mess. 4) Manually feed the paper back into the printer ("leading edge" first) and print again. This time the image will be printed on and lined up perfectly on the small piece of P-n-P. jj ...doing .5mm trace spacing work with P-n-P blue! > You can also use the press-n-peel blue to make a nice (black) silkscreen. > Just make a second P-n-P "template" of your silk screen image...remember [quoted text clipped - 7 lines] > > jj >>> Nice work! >>> I think it's about time I got myself a bubble etch tank, been using a [quoted text clipped - 9 lines] >> various shops (Maplin, pet shop, garden centre). Came together rather >> nicely, I reckon. :-) > You don't have to waste a whole sheet of P-n-P just to print a small > board: 1) Print your image on plain paper first. [quoted text clipped - 5 lines] > ("leading edge" first) and print again. This time the image will be > printed on and lined up perfectly on the small piece of P-n-P. That's a good idea. I didn't use a whole sheet, but did three prints of a small board along the width at the leading end (the board size was a good fit for three across). I'm likely to want to make some more of these boards, so there was very little loss. The blue plastic does come out a little wrinkled but seems to go through a second time okay. I can see that your method will ultimately produce less waste, so I'll give it a go. > jj ...doing .5mm trace spacing work with P-n-P blue! Viewed up close, how clean would you say the edges of the tracks are? I felt mine looked a bit rough, although I did over-etch. Have you done any double-sided boards with it? If so, how do you handle registration of the layers? SignatureMelodolic Spielberg They are not perfect but are fine for .01" traces, there is little room for error though. Use fresh, warm etchant and agitate like mad to get it done quick. Yes on the double sided. I put an extra via at each corner as registration marks. Iron one side and drill the registration marks. You have to remove any hole "fuzz" from the drilling. Then hold the PCB to a bright light and "try" to line up the PnP for the other side. This was ok but not to good. I've had better luck by drawing a line around the perimeter of the board, make sure it prints out. Then align this perimeter line with a corner* of the PCB. Iron one side, flip, align the other side with the same corner, iron. *If the edges of your raw PCB are not "sharp" it will not be easy to get good alignment. If so, cut then first to get a good edge. A cheap ($50, plastic housing) table-top diamond blade wet tile saw from home depot (or was it Lowes?) works great. jj > Viewed up close, how clean would you say the edges of the tracks are? I > felt > mine looked a bit rough, although I did over-etch. > > Have you done any double-sided boards with it? If so, how do you handle > registration of the layers? > They are not perfect but are fine for .01" traces, there is little > room for error though. Use fresh, warm etchant and agitate like mad > to get it done quick. Do you use a tray or a tank? > Yes on the double sided. I put an extra via at each corner as > registration marks. Iron one side and drill the registration marks. > You have to remove any hole "fuzz" from the drilling. Then hold the > PCB to a bright light and "try" to line up the PnP for the other > side. This was ok but not to good. This is roughly what I've been thinking of trying, except I was considering drilling a couple of thin pilot holes and pushing pins through the top layer PnP and then the board. If a pair of diagonally-opposed corners are pinned, about half of the area is still accessible to the iron, so it should be possible to get enough adhesion before removing the pins to finish. > I've had better luck by drawing a > line around the perimeter of the board, make sure it prints out. > Then align this perimeter line with a corner* of the PCB. Iron one > side, flip, align the other side with the same corner, iron. *If > the edges of your raw PCB are not "sharp" it will not be easy to get > good alignment. If so, cut then first to get a good edge. That could be a better option. As a matter of interest, how do you do vias? Didn't there used to be some sort of little hollow, stubby 'pins' specific to the purpose? > A cheap ($50, plastic housing) table-top diamond blade wet tile saw > from home depot (or was it Lowes?) works great. Interesting, but I'm getting short on space. :-) I should be able to skim the edges square in the milling machine, however. SignatureMelodolic Spielberg Just been using a tray. Sounds like the pin method of alignment should work. Once you get it aligned you should be able to remove the pins. A little finger pressure is usually enough to keep the PnP from sliding around on the PCB. I always use a blank sheet of paper between the iron and the PnP to help the iron slide better. Run a wire through a hole and solder both sides for a via. Just make sure you don't place a via under a SMD chip! >> They are not perfect but are fine for .01" traces, there is little >> room for error though. Use fresh, warm etchant and agitate like mad [quoted text clipped - 34 lines] > Interesting, but I'm getting short on space. :-) I should be able to skim > the edges square in the milling machine, however. >I always use a blank sheet of paper between the iron and the PnP >to help the iron slide better. > joseph Indeed. >Run a wire through a hole and solder both sides for a via. Pseudo-PTHs is the part that makes DIY a pain. >Just make sure you don't place a via under a SMD chip! Yup. Learning to use the *keepout* command early on will make life much easier. . . Joseph, It would be nice if you would fiollow the convention in these groups: Trim and bottom-post. >Have you done any double-sided boards with it? >If so, how do you handle registration of the layers? > Melodolic Spielberg :I put an extra via at each corner as registration marks. :Iron one side and drill the registration marks. : jj ( joseph) I agree up to that point. I used stick pins thru the holes to line up side 2 of the blue stuff. Start ironing where the pins aren't and after enough of the toner has adhered, pull the pins out and finish ironing. . . BTW, Walter Harley's layout/etching philosophy is closer to mine than is yours: http://groups.google.com/group/sci.electronics.design/msg/4113c39b765f9a03?q=zzz +the-faster-your-etching-will-go+zz-zz+no-reason+a-couple-of-traces-on-*-*-bare- board+the-more-copper-you-can-leave-on-the-board news:bo9r37$haf$0@216.39.172.65 >>You don't have to waste a whole sheet of P-n-P just to print a small >>board: 1) Print your image on plain paper first. [quoted text clipped - 20 lines] > Have you done any double-sided boards with it? If so, how do you handle > registration of the layers? photo injet paper with the image on the glossy side works wonders, just detach with water. also, i have seen the glossy pages from mags be used SignatureReal Programmers Do things like this. http://webpages.charter.net/jamie_5 > You can also use the press-n-peel blue to make a nice (black) > silkscreen. Just make a second P-n-P "template" of your silk screen > image...remember to mirror image it! Iron it on the top side of your > PCB. Coat with some acrylic spray and presto. I forgot about that - the similar product mentioned in another thread came with 'white' PnP sheet for doing that - didn't occur to me that the blue PnP black resist would do the same job! Having tried cleaning it off, the etch resist does seem pretty tough. > Do this BEFORE you > drill otherwise you won't be ablt to iron the P-n-P onto the rougher > drilled surface. I got a flat a surface after drilling by deburring using a spot cutter. That said, the holes might upset the application of the resist. (I'd drill after etch anyway...) > Also... use a very small inner hole size for your vias. This will > let your drill bit 'find' the center easily. The drill bit will of > course open it up to the proper size. I'm using EAGLE and, so far, the pads all seem to have kinda largish holes - will look for ones with smaller ones, though . The drill bit is attached to a small vertical milling machine. I move the board by hand, looking first from the front to adjust the X position, and then from the side to adjust Y. That first board had no issues with hole alignment (not perfect, but the 8-pin DIL skt went in okay). SignatureMelodolic Spielberg |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2009 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.