pcb etching

Discussion in 'General Electronics Chat' started by adamclark, Aug 11, 2014.

  1. adamclark

    Thread Starter Member

    Oct 4, 2013
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    I currently have another thread going for my diy psu. Im going to need to be making some pcb's real soon as im progressing faster than expected.. I have never etched a board before so I would like to do it as easy as possible.. ive searched and it seems like theres a dozen different ways to do it.. I do like the idea of uv etching though.. the less chemicals the better.. I don't think im going to need dozens of tiny traces at first. thanks for any ideas you can add for me.
     
  2. adamclark

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    Oct 4, 2013
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    and before someone says it,, ive tried searching the site, but the search function will not work for me.. everything I search returns 0 results...thank you
     
  3. jpanhalt

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    UV does not etch the boards. It is used to make the resist pattern before etching and utilizes more chemicals than the toner transfer method. At a minimum, the UV method requires a chemical developer for the photographic image. With a positive resist, which I suspect you would use, that developer can be as simple as a solution of lye in water.

    For etching, I recommend ferric chloride. It is a robust etchant and is difficult to screw up. Some people prefer HCl and hydrogen peroxide. That works, but in my experience, it is more sensitive to conditions than ferric chloride.

    All chemical etchants involve oxidation of unwanted copper on the PCB. They all produce waste; although, some users reuse that waste for making additional etchant.

    John
     
  4. djsfantasi

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    Bill Marsden has a thread on making PCBs. It can be found at this link - How I Make PCBs
     
  5. adamclark

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    Oct 4, 2013
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    thanks guys..idk why the search function doesn't work for me..
     
  6. MikeML

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    This returns lots of posts that contain both words:

    [​IMG]
     
  7. GopherT

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    The UV process works well if you can find the chemicals at a good price.
    I have used the MG Chemicals photo boards - coating boards yourselves is a pita and no faster or better than laser toner transfer method.
     
  8. adamclark

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    Oct 4, 2013
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    im not sure what the problem is for me searching.. it always returns 0 results.. I just typed in 555 timer and got 0 results. and I know for a fact there are hundreds of 555 threads.. as far as etching goes, Im starting from scratch and don't have any equipment at this point.. so I guess im looking for the way that requires the least chemicals and is the most foolproof so I can gain experience. At the moment im building a psu so the pcb's I need wont be to complex.
     
  9. jpanhalt

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    I can appreciate your frustration with Internet searches that always show "0" returns. It is good you discovered that little challenge.

    Now, you ask for the etching method that requires the "least chemicals." Did you my my post also not appear on your monitor? Ferric chloride is ONE chemical dissolved in water. It is a bit hard to conceive of a method doable at home that would involve fewer chemicals.

    John
     
  10. adamclark

    Thread Starter Member

    Oct 4, 2013
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    I did read it, then I read bill marsdens article and it covers the ferric chloride method but that's just for etching. I am probably most certainly going to use it to etch as you stated but I also would like some opinions on the actual transfer methods. as I stated my circuit isn't going to be overcomplicated. I was considering just using a resist marker to draw my traces on the copper clad board and then using the ferric chloride to etch.. would this even work? I don't want to buy a laminator and laser printer for the toner methods. at least not yet until my needs make the purchases necessary. My bad for not being as clear as I could be, I tend to think faster than I type
     
  11. MikeML

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    [​IMG]
     
  12. Lestraveled

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    Here is my method for home made PCBs.

    1. Print your PCB pattern onto clear transparency film. (The stuff used for over head projectors.) Get the kind that works with your printer. You will need 3 copies.

    2. Take the 3 copies and align them perfectly. Tape them together. This makes the pattern very opaque.

    3. Buy pre-sensitised Positive resist printed circuit board stock. Place your transparency on the board and sandwich using a pane of glass and foam on a stiff surface.

    4. Expose to direct sunlight. Exposure time will between 4 and 20 minutes. Do a test run on a small sample to establish the correct exposure time. This is the most critical part of the process.

    5. Develop, etch and drill.
     
  13. jpanhalt

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    My method is similar to yours with two differences:
    1) If my transparency is not dense enough without needing multiple copies, I fill in the spaces with a white board black marker: http://www.electro-tech-online.com/blog-entries/improved-laserjet-transparencies-for-pcb.213/ Alternatively, an ink jet printer will give sufficient density for a single transparency thickness.

    2) I use regular 15W fluorescent light bulbs for exposure. That gives a reproducible exposure of about 15 minutes.

    John
     
  14. GopherT

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    Yes, you can just use a SHARPIE marker and etch with ferric chloride. Then drill and mount your components. It has been done this way for years.
     
  15. Lestraveled

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    I agree, my inkjet printer makes a denser pattern than my laser printer.

    Here is a picture of my latest PCB.
     
  16. nerdegutta

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    Dec 15, 2009
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    This is how I do it...

    This is when I need more than one board.

    If I need just one board, I use toner transfer, with glossy paper from Stapler, and a clothing iron.

    Some pictures.
     
  17. Lestraveled

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    nerdegutta........very very nice.
     
  18. Lestraveled

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    You can use the above methods to make double sided boards also. You take your patterns and tape them to a strip of PCB stock. Of course you align the patterns very carefully when you tape them. The top side transparency needs to fold out like a cover of a book. This will allow you to tape the sensitized PCB to the strip of PCB stock. This holds everything in registration when you flip it to expose the second side.
     
  19. nerdegutta

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    Thank you!

    I made this box for making double sided PCBs.

    I tape the tranparents on three sides, so they make some kind of pocket, and then I place it in the box. It get exposed on both sides at the same time. :)
     
  20. jpanhalt

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    When it gets so complicated as to need double sides and a large number of vias, I go commercial, including solder resist. The price difference was trivial. I used to use my exposure apparatus for double-sided boards regularly.

    John
     
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