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Having a little problem with PCB making .

Discussion in 'Circuit Simulation & PCB Design' started by BGAmodz, Nov 3, 2013.

  1. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    Jim Williams at Linear once characterized anyone who "wanted" to design their own switcher as crazy. If you don't know who is was, look him up. He was an accomplished engineer who wrote with an unmistakable panache.
    upload_2013-11-4_20-6-49.png

    Here is one of his more popular application notes: http://cds.linear.com/docs/en/application-note/an35f.pdf

    As for designing your own, I would strongly recommend one of the National (now TI) Simple-Switcher IC's plus their design aids.

    John
     
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  2. BGAmodz

    BGAmodz Member

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    LOL , yes i will try to do it but its clear am not going to make one from scratch , of course i will use pre-designed sub-circuits to build the final one .
    The crucial thing is actually making the right calculations , and security precautions .

    The reason i want to build one is due to power consumption witch is very low compared to a linear one , also i can make smaller ones , and the most important thing for me is that i can design one according to my needs ( current/voltage outputs , wattage ) , i can also incorporate SMPS internally on a automated system by merging it on the same machine circuitry .
     
  3. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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  4. dave

    Dave New Member

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  5. BGAmodz

    BGAmodz Member

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    I will for sure take a look , always nice to learn from the pros , but before doing that i need to give a good read at my book , its Pressman's "Switching Power Supply Design" book
     
  6. mvs sarma

    mvs sarma Well-Known Member

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    off late I find some new paper sold on ebay is dam cheap and working superb . here is the link,
    http://www.ebay.com/itm/170900415631?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

    i felt much more comfortable
    in registration , clean transfer and easy pull out and post etching the copper surface is shining even after few days of exposure to atmosphere , A photo of my pcb made using this paper is attached.

    @ BGAmodz, Incidentally
    what printer did you use and whether a laminator or electric iron used for transfer please?
     

    Attached Files:

  7. BGAmodz

    BGAmodz Member

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    Hi sarma .
    I used a Moulinex optimate 60 chrome plus iron , as for the printer i don't remember the name , but the guy who done the print for me said its a 200 $ printer .
    For the paper i used i had hard time removing it from the card , so for a better quality circuit i prefer using photo paper or magazines paper , as it going to be easier to peel off .

    After reading in the internet , before puting the paper on the copper , make sure you clean the card's copper surface with ACETONE , after that you can iron the paper on it with mid/high temp (silk/laine) setting .

    Next for optimal transfer , put the back of the card surface on the iron heater ( settings at max) , this should allow the rest of the ink to stick optimally .

    Next step is let the card cool down and put it in water ( mixed with liquid soap ) for about 4 minutes , then peel off .
    Now for the etching there is two possibilities , using ferrite chloride (cheaper & for simple circuits) or using a mix of chloridric acide and 99 %Hydrogen Peroxide ( used for complex circuits ) .

    NB : When you put the card on the chemical liquid , place the printed side directly on the liquid and make the liquid moving , this will help etching faster .
    last part is removing the ink with ACETONE .
     
    Last edited: Nov 5, 2013
  8. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    You will be better off, if you stick to ferric chloride for the time being. Even commercial PCB manufacturers use it. Ferric chloride is reasonably fast (particularly if warmed a little), gives the sharpest etched edges, and produces the least undercutting. In fact, it is the standard to which other methods of etching are compared.

    John
     
  9. panic mode

    panic mode Well-Known Member

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    normally i just order pcbs but never feared making my own, specially for a quick prototype.

    paper is something one needs to experiment with. based on my experience, ideally it is smooth/glossy and easily dissolves in water. thicker paper is more stable but much slower to soak or heat (cold toner does not stick to copper).

    copper must be cleaned (oxide and fingerprint free) if you want toner to stick to it. toner is a plastic and ironing melts it, and as mentioned, this is what allows it to stick to copper. but melted plastic is not very strong, i let it cool down first before soaking, and after soaking, i rinse it for few seconds under cold water. this makes toner hard and tough so i can easily get rid of paper. i remove any leftovers using large eraser and running water. if toner comes off too or is removed easily, something is wrong.

    before etching i inspect board and if there is freckle or two i touch it up. most people recommend permanent marker (Sharpie) for touchup but imho standard permanent markers are pretty lousy at keeping copper safe (still better than nothing).

    approx prep time:
    start iron
    print
    clean pcb - 2min
    align paper and pcb, secure it - 30sec
    ironing - 2 min
    turn off iron
    cool off - 2 min
    soak - 3...5min
    rinse - 5sec
    peel - 10 sec
    rub off any paper traces - 2min
    inspection - 2min

    etching, drilling, removing toner etc. takes another ~30min.
     
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  10. BGAmodz

    BGAmodz Member

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    It is also recommended to use the chloridric acide and 99 %Hydrogen Peroxide mix for SMD prototypes , it is good for thin , narrow , and edgy circuit lines , like on this one , but i wonder how they applied the red mask and keeping the solder pins intact ??
    [​IMG]
     
  11. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    I don't believe any commercial PCB maker uses HCl/hydrogen peroxide for etching. Will you please cite the source for the recommendation you found for SMD prototypes?

    John
     
  12. mvs sarma

    mvs sarma Well-Known Member

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    thanks for the Nice discription

    if you can buy these papers on ebay, try them
    i am just able to peel off even while the post ironing is still cooling. Appears as if the coating on paper might be Teflon spray

    and it is accepting toner very well and releasing
    now a days they use ammonium persulphate
    in the industry.
     
    Last edited: Nov 5, 2013
  13. BGAmodz

    BGAmodz Member

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    Ok smd is just an example where sharp edges and thin line are usually found .
    Sorry i've lost the link fpr the information .

    Sarma ; today i have collected some magazine papers ; the paper was just perfectly adequate for the task

    But the funny thing the guy wouldn't print it for me ; he said that this could damage his lazer printer .
    Time to by my own
     
  14. mvs sarma

    mvs sarma Well-Known Member

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    Same was the story here too, in Hyderabad, India, Even after taking say 0.6$ or so per print , they grumble. Having felt insulted, I bought one HP Laserjet P1007 , just for Hobby.

    but the paper rag cleaning close to track edges, and in the drill holes, the head ache still remains what ever best magazine paper you try to use.

    all the best to you.
     
    Last edited: Nov 5, 2013
  15. BGAmodz

    BGAmodz Member

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    Actually i managed to print on 2 magazine papers , but the first one's peeling process failed , the ink comes off with the paper , maybe i didn't heat it enough .

    In the mean time am waiting for the second on to cool down after a long ironing .
     
  16. BGAmodz

    BGAmodz Member

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    The second one looks perfect , here is the result of the transfer :

    [​IMG]
     
  17. BGAmodz

    BGAmodz Member

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    And now the final result :
    [​IMG]
     
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  18. mvs sarma

    mvs sarma Well-Known Member

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    Lovely pcb
    let me congratulate you.
     
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  19. bhowden

    bhowden New Member

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    I found Eagle very non-intuitive for a windows user. For me, Dip Trace much better. Eagle libraries can be imported and there is no size restriction for the free version but you are limited to 2 sides and 500 holes. I also had good luck with magazine paper. I have never had any issues with it gumming up my laser printer (HP with aftermarket toner).

    Brian
     
  20. Mosaic

    Mosaic Well-Known Member

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  21. BGAmodz

    BGAmodz Member

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    Hi am back on this topic again .

    Even if i have succeeded to making some PCBs , the copper quality is bad , it gets dirty very fast and also gets removed due to solder heat.

    do you have any idea on some alternative type of metal besides of copper , some thing resistant like in high end PCBs and also suitable for SMD layouts ?
     

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