Printed circuit boards

Discussion in 'General Engine Discussion' started by Gordon, Mar 7, 2015.

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  1. Mar 7, 2015 #1

    Gordon

    Gordon

    Gordon

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    I have been playing around recently trying to add ignition systems to my existing engines. The thought is that I will probably try to sell some of them before my kids and grand kids get stuck with the job or just dump them. Most of the engines have been running with my "ignition box" which consists of a SLA battery, an automotive coil and condenser.

    The CDI ignition is compact but beyond my capabilities. I have built a couple of transistor systems similar to TIM-6. The problem is the printed circuit board. Universal boards are available but making connections between components gets messy. bending the pins on the first component to the next component works but makes a messy board and does not always work when the components are far apart or multiple connections are required to the same point. Boards with traces between several tie points are available but it never seems to make for a neat solution. I have tried to make solder bridges between points but that does not work well. The solution would be to make custom boards.

    First question is: Is there a good way to make connections between components on a universal board other than soldering to the pins on the bottom of the board?

    Second question: I have a small Grizzly CNC mill which I would assume could be used to make custom boards. Copper clad sheets are available and I assume that removing the copper where you do not want traces is the way it is done. It is like making a statue where you start out with a block of marble and remove everything which does not look like a horse. There seem to be software programs which can produce circuit boards. Some are free and some are way beyond a price range for the home shop.

    Any pointers on how to proceed as far as setting up the mill or how to proceed with a software program are welcome. Am I missing something? Should I be looking at etching for boards?

    I am aware of the fact that there are companies who will make boards for a reasonable price. I am looking at this as a learning experience as much as just a way to get results. Obviously I do not want to spend a lot of money and would like to use existing equipment if possible.

    Thanks: Gordon
     
  2. Mar 7, 2015 #2

    canadianhorsepower

    canadianhorsepower

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  3. Mar 7, 2015 #3

    cwelkie

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    Hi Gordon,
    I'm far from an expert at milling printed circuit boards (pcb's) but have had some good success doing it on my cnc router so you should expect good results from a mill.

    I used an 1/8" shank, 15 degree engraving cutter to cut away the copper around traces and solder pads. You don't need to cut everything you don't need away (like a chemical etch does). One consideration is holding the blank pcb down so it is very flat. The thin stock I was using had a curve to it and when only removing 8 or 10 thou it doesn't take much of a curve to be a problem. In the end, I used double-sided tape on a piece of medium density fibreboard.

    Not knowing which CAD or Cam software you use I can't share many tips in that regard. I use CamBam to both draw the layout and generate the G-code. The layout is a single track between component or wiring pads that are spaced according to the physical devices and your schematic. CamBam has an offset function that allows one to put an outline around each element of the layout offset a consistent distance away from centre. The engrave function can then be used to create g-code that follows the offset lines. In the end you end up with conductive traces and pads surrounded by unused copper.

    I hope I've helped somewhat and not added confusion. If you share the software you use with the mill, odds are someone here has done what you want to try already.

    Have fun learning about milling pcb's ... sure beats messing with chemicals and masks and all that other stuff if you aren't doing it "all the time".
    Charlie
     
  4. Mar 7, 2015 #4

    Gordon

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    I have a license for MACH 3 and have used CamBam demo. I am familiar with and have used Visual CAD quite a bit in my previous working life as a machine designer and fabricator. Visual is a 2D program and I have used it to produce DXF files for producing parts for my model engines. I have not used the CNC mill a great deal. I got it mostly to play around with for a learning experience.

    Looks like the week end may be spent doing more reading.

    Gordon
     
  5. Mar 7, 2015 #5

    canadianhorsepower

    canadianhorsepower

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    Hi Gordon

    the link that I posted include everything, program ,
    tutorial, video, it even have a cam processor include

    this is what we use at the college for platform in building
    circuits to PCB board

    Luc
     
  6. Mar 7, 2015 #6

    cwebs

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    I am also new to making PCBs and use Eagle. You will also need to get pcb gcode and install it with Eagle freeware. Go to youtube and do a serch for Eagle cam and PCB GCODE. It will do a great job and make all the gcode and drill gcode for you. And it's free. There is a little hill to clime when learning Eagle but there is lots of info out there. I made my first board from a gerber file I found online and was amazed at how fast it worked. Gcode was right on. Youtube should be your first look. Hope this helps. Carl
     
  7. Mar 7, 2015 #7

    canadianhorsepower

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    enjoy youtube


    [ame]https://www.youtube.com/watch?v=DVKAV7udp3Y[/ame]

    Luc
     
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  8. Mar 7, 2015 #8

    cwebs

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    One thing that he didn't mention in preview window, That I found interesting is the colors of each pass of the bit when cutting. The colors are the same as the resistor color code. IE. The first pass is Brown, Second pass is RED, third pass is orange, forth is Yellow, ETC. FYI, Carl
     
  9. Mar 7, 2015 #9

    TorontoBuilder

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    I've made pcb boards both using copper etching solution, and manually milled boards using dremel tool... I'm familiar with whats required using cnc milling too.

    In my opinion though, the best option for a small number of simple very high quality boards is to use a fulfillment house to manufacture professional boards. I used Oshpark.com for my recent projects. Their board quality is outstanding, and has the benefit of solder masking to make soldering much easier without worry of short circuiting connections.
     
  10. Mar 7, 2015 #10

    Gordon

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    I agree that the most efficient method is to go to one of the places who specialize in that. On the other hand if we thought that our hobby activity was worth more than minimum wage we probably would not be doing it in the first place. If I kept track of the time I spend making a model engine and calculated what I could sell it for I doubt that I would be making minimum wage. It is a hobby so we have different expectations. It is like fishing. If you add up the cost of fishing gear, boat, travel etc it is much cheaper to just go the the fish market. Learning new things brings satisfaction in itself.

    Actually for me at least it is very liberating after spending most of my life self employed, to just do something because it is fun or interesting instead of making money. I realize that not everyone is retired and spending some money instead of devoting a lot of time to single steps in the process is the best answer.
     
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  11. Mar 7, 2015 #11

    cwebs

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    Hi Gorgon. I'm also retired and would rather do it my self and don't care how long it takes. Sounds like you have every thing you need to route your own boards on your mill. If you wanted a small number of boards with everything done for you and looking good also you can alwas send in the gerber files. Eagle makes everthing you need to have boards made. But you still had to make the files yourself. Then it's a couple weeks or more before you get them back. You made the gerber files and gcode with pcb gcode so you can make another board at any time because you have the .nc files. You can have it both ways with the same amount of work. Then mill out one to test and make changes if needed. That's the way I look at it. Carl
     
  12. Mar 7, 2015 #12

    canadianhorsepower

    canadianhorsepower

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    or you can go this way

    https://www.kickstarter.com/project...cuit-board-prototyping-machine?ref=nav_search
     
    Last edited: Mar 7, 2015
  13. Mar 7, 2015 #13

    TorontoBuilder

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    It's not a matter of cost, but rather that I choose to have the highest quality builds possible, and if that also possible at a lower cost all the better. For the same reason many people purchase specialized ignition components rather than make their own. But then I'm only speaking from my own experience making my own circuit boards...
     
  14. Mar 7, 2015 #14

    canadianhorsepower

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    Toronto Builder
    check my last post

    cheers

    Luc
     
  15. Mar 7, 2015 #15

    TorontoBuilder

    TorontoBuilder

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    cant access facebook... I cant remember my FB password...

    oops I see its changed to kickstarter link. I dont build enough pcbs to justify $1500 expense of that machine. Nor have I ever required a circuit board in a cpl hours... but I'm sure that for companies who offer 3d printing and laser cutting to public it wud be good addition to the shop
     
    Last edited: Mar 7, 2015
  16. Mar 7, 2015 #16

    dnalot

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  17. Mar 10, 2015 #17

    Nerdz

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    Im a little late to the party.

    Ive used a laser printer and photo paper for years! About a few years ago I started using a sponge with ferric chloride to etch the boards in a matter of minutes. Recently, I started using OSHpark. 3 PCBs are very cheap depending on the size. I use the service if I am waiting a week for parts, and if I want it to look somewhat nice, Otherwise I go the DIY method. For someone unfamilar with Electronics, I would actually use a breadboard (the soldering kind). Just be sure to plan where you want everything before hand.
     
  18. Mar 13, 2015 #18

    Gordon

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    Actually that is pretty much the the conclusion I have come to. I would only be making a few PCB and they would be personal use, not for sale. I looked at the free software etc and the learning curve is too steep for my limited use. Even us retired folks prioritize sometimes.
     
  19. Mar 13, 2015 #19

    TorontoBuilder

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    Actually, I have to disagree here. The software is very easy to learn and it's free.

    I'm in my 50s and haven't done any electronics in decades. Most people who know schematics well enough to build breadboard you can learn to use eagle software in a very short time, ie an evening. Thats how long it took me to learn it.

    The benefit is that you can output to either laser printer or to a pcb manufacturer. You can also design much smaller surface mount component circuits which are small, inexpensive and durable. Not likely something you can make w/ transfer paper and certainly not w/ a breadboard.

    The reality is, its typically LESS expensive to have a manufacturer make boards rather than order transfer paper, etching chemicals etc and you end up with VERY high quality board unobtainable with DIY methods.

    That's a very real benefit when building ignition circuits or circuits to control tooling where you want 100% reliability.

    As for costs, the average price I paid per board, including shipping is $3.00, and I only had to order 3 copies. Many of my boards cost less than $1.00 a piece.

    I hear too that soon OshPark will be offering assembled PCB boards too for those ppl not up to surface mount soldering.

    My advice to people is that if you need an ignition circuit or other PCB take the time to check your options before allowing someone else to convince you what is or is not an option suited to your needs. Keep an open mind...

    I've attached pics of a few of my boards, including the smallest set of surface mount circuits, up to my largest board that I had to mount two huge wirewound resistors on to dissipate heat.

    photo (12).jpg

    photo (14).jpg

    photo (15).jpg
     
  20. Mar 13, 2015 #20

    RonGinger

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    I tried to make a PCB for my power feed for a mill using arduino. The software is easy enough, but the parts library is the big issue. I was using some push button switches I had on hand, purchased from a surplus place so I had no idea of part numbers. I kept browsing through the parts libraries and never could find a button I was sure would fit my parts. A similar problem for any other components. If you are going to make a board, and order all new components from a place that has a library then it really is simple.
     

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