Alternatives to Chemical PCB Process

Discussion in 'General Electronics Chat' started by iONic, Aug 18, 2008.

  1. iONic

    Thread Starter AAC Fanatic!

    Nov 16, 2007
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    I've come across a few alternatives in my wanderings about the internet such as CNC etching or Laser etching, but have seen no real details posted here in the forums. This would be a good place to offer up your alternative processes or theoretical new processes for etching PCB boards.

    If you have an alternative process, either wet, using alternative, less abusive chemicals, or a dry process, please post details here.

    Thanks
     
  2. kammenos

    Active Member

    Aug 3, 2008
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    mechanical - chemical and electrical etching methids can be found at the following link.

    http://www.pcbheaven.com/workbench/pcbmaking/?prgn=3

    Mechanical method i think is not discussed there but is supposed to be done using a CNC machine. You may ask for more info about CNC machines but is not a very good way of making PCBs.

    I personally use chemical way using feCl.
     
  3. mark60

    New Member

    Apr 9, 2009
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    I have Accurate 360 PCB prototyping machine and I’m very happy with the results.
    The quality of boards produced is extremely good. No chemicals!
    Here is the machine www.accuratecnc.com/A360.html
    I did double sided 4mil traces, 4 mil spaces, no problems atoll.
    Years ago I tried toner transfer with relatively good success (10-12mil traces), but this can’t be compared with Accurate 360 (100% success at 4/4 mil jobs).
    I tried also with some universal CNC machines, big pain, small repeatability of the results.
    So for me the best way is PCB prototyping CNC (not any CNC).
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    I've seen good results with CNC engravers. We had one at my last job.
     
  5. AchMED

    Active Member

    Aug 5, 2008
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    My school has a CNC machine for PCB milling and drilling it gives excellent results, mind you it cost about as much as new truck not including the software and dongle. I’ve heard mixed results for the hobbyist ones ($1500 to $ 5000 range).
    The downsides to it are setup time and they can be slow for complex (dense boards), definitely not good for mass production. The bits are pricey and they snap easy if you aren’t careful. We could use either the CNC mill or chemical method I always preferred the CNC mill.
     
  6. leftyretro

    Active Member

    Nov 25, 2008
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    Laser burning sounds so cool, anybody actually fabing PCB using one? How much power would be needed for 1 or 2oz copper?

    Lefty
     
  7. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Maybe the operative word is etching. Lasers and chemical etching are not much different in terms of toxicity risk. Milling might be a bit lower risk

    But, why etch? Conductive polymers can just be printed with inkjets. Here is an article from 2000:

    Science 15 December 2000:
    Vol. 290. no. 5499, pp. 2123 - 2126
    DOI: 10.1126/science.290.5499.2123

    I can't wait to just load a copper cartridge and print away. Or, maybe we could plate a conductive image from a laser printer with copper. A third option would be to print with a funtionalized ink and then allow a proper, non-electrochemical deposition of aluminum, copper, silver, or gold. It is quite easy to deposit some metals onto non-metallic surfaces.

    John
     
    Last edited: Apr 9, 2009
  8. SgtWookie

    Expert

    Jul 17, 2007
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    A few decades ago, I carved out a Jfet and cap on a ceramic substrate using a high-powered laser under a microscope. Does that count?

    Set-up costs would be rather prohibitive though, just for the clean room...
     
  9. mark60

    New Member

    Apr 9, 2009
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    LPKF laser based machines are good choice, but you have to spend 150K+ to have one, they DO NOT DRILL, and if you don’t have enough projects to load this machine it is simply waste of money.
    I think the laser is about 1.0 kW
     
  10. mark60

    New Member

    Apr 9, 2009
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    Couple of weeks ago I ordered a professional vacuum (http://www.accuratecnc.com/A103.html).
    I got it last Friday. It takes a bit more space but is amazingly quiet and has a submicron filter.
     
    Last edited: Apr 16, 2009
  11. AchMED

    Active Member

    Aug 5, 2008
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    Wheres the price list on the Accurate website?
     
  12. electronictech

    Active Member

    Apr 1, 2009
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    A wild idea that might be possible for the chemically inclined.......what if you could make the circuit traces out a material that was easy/safe to work with and it had an affinity for solder? You make the traces with this material, then either pour molten solder over the board or dunk the board into a solder pot....hopefully the solder would stick to this material and your boards would be made.

    dunno, just throwing some ideas out there.
     
  13. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Check my post #7. Conversion coatings, say to silver or tin, have a disadvantage of being thin. They can be thickened, however.

    John
     
  14. nigelwright7557

    Senior Member

    May 10, 2008
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    Mechanical etching is not very good.
    I was a member of a chat group for using cnc machines for etching and the amount of problems people were having was incredible.
    Over etching and under etching and problems with the converter program were amonst some of the problems.
    Not least is the cost of a cnc machine.
     
  15. Wendy

    Moderator

    Mar 24, 2008
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    It depends on the expertise of the user. I have a friend with a home made CRC machine (he is heavy into robotics) that does really clean work. Commercial machines also do well.

    Conversly, I've heard a lot of complaints about etching. As with everything, practice makes perfect, there is nothing wrong with either process.
     
  16. mark60

    New Member

    Apr 9, 2009
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    You may ask for quotation !
    Accurate 360 (www.accuratecnc.com/A360.html) base price was about $8.6K
     
  17. pps

    New Member

    Apr 28, 2009
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    Hello,
    We have an accurate 350 in our university and I did my first board on it (HC11) :).
    The vacuum is very impressive and they told me that it has a submicron HEPA filter in order to maintain the air quality requirements for public places. I don’t know is it the one that accurate cnc offers or from other vendor but was very quiet!
    Also I asked about classic prototyping (using chemicals) and the answer was that it is very expensive to follow the environmental rules covering the chemicals handling and more dangerous to expose students (usually without experience).
     
  18. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Hmm... If they were about $2.5K they would sell a lot.

    But it's a recession now, think of how many nice double sided PTH solder masked etc PCBs you can have commercially made for $8.6k...

    Or how many sheets of pressnpeel film you get for $8.6k?? ;)
     
  19. mark60

    New Member

    Apr 9, 2009
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    Only spindle for 60K RPM is $3K. (You may check Alfred Jeager or Kavo).
    And if you order 24 hours turn, you will have 3-4 orders for $8.6K :)
     
  20. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    It depends on the density and complexity of the PCB. For the kind of R.F. work I do, a Dremel works wonders!

    p.s. Grinding fiberglas PCB substrates is hazardous...almost as bad as asbestos. If you do this, be sure you wear particle masks and goggles. I always do this outside, as well (except when it's 40 below!)

    If you're using phenolic PCBs, you can use an Xacto knife (slice and peel method), but it's pretty tedious. However, a Dremel with a grinding wheel makes real short work of this process.

    The problem with these mechanical methods, is that they're not real suitable for mass production, as you can imagine. But for prototype work, it's fine.

    Eric
     
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