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Thread: very general questions re: fabrication of boards, panels, mechanicals

  1. #1
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    very general questions re: fabrication of boards, panels, mechanicals

    It's a new year, and time to try new things.

    If I want to get a PCB made, maybe a very small batch, what files do I need to send? Is it just a PDF? How good do they have to be? To me, this is one of those things where until you have done it successfully you don't know enough to be able to do it. So I have waited years.
    What's a decent example of a simple PCB layout? How was it made? How do I know it was well-printed when I get my proofs back?

    I will never need more than four of anything. There's zero chance of me ever putting in a bulk order for 999 pcbs. Mainly I am interested in reducing build time and increasing reliability.

    I love working with electronics, but I am really, really dumb when it comes to things I have never had a verbal conversation about. I don't think in pictures at all, so making a PCB layout is a matter of faith. (I have a massive project in Audio Library Design Tool and due to many edits I lost the layout coordinates. It took many hours to pull the original layout out of the spaghetti. I don't like chaos or mess any more than anyone else but I seem to lack the grey matter to be able to straighten a network of components with many nodes.)

    Along the same lines, I don't have anything like a machine shop. No CNC for me. I don't even have Baby's First Drill Press, or a mitre saw to make nice corners for my enclosures. (would I like a 3D printer? sure... maybe some day) So, same basic question here: If I need a customized enclosure, or even just a sheet of aluminum with some through-hole controls, what do I need to provide to a vendor so they will be able to do what I need? I have never made a mechanical diagram in my life. Flunked machine shop as a kid. My designs had holes worn in them from all the eraser use.

    The projects I am doing with the Teensy are far better than anything I have ever done before. I would like to be able to consider giving some of these projects a proper home.

    Thanks,
    Ben

  2. #2
    Senior Member PaulS's Avatar
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    When it comes to manufacturing of small qty PCB's, I have good experiences with PCBway.com.
    For designing the PCB and doing the schematics and layout, I used Autodesk's EAGLE. It's free for small PCB's <80cm2. The learning curve is not too steep and you can easily upload your Eagle design to PCBway for manufacturing.
    The five small PCB projects I had PCBway manufacture looked pretty good and I received the PCB's within 5 calendar days after uploading the PCB design - not bad at all!
    From experience I can say that the PCB quality is pretty good, if not excellent. I will use them again for upcoming projects.

    Hope this helps and success,
    Paul

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    Ben:

    To produce a PCB, using KiCAD is a good place to start. I have produced several boards, with requirements ranging from very simple to quite complex, for both hobby & work (I am a software/systems engineer, but because we are a very small group, I do get to dabble in hardware a bit). It is an excellent open-source product that is still being actively maintained & updated.

    You can go <here> to find a tutorial on using KiCAD that I wrote a couple of years ago for a community-sponsored DIY group that I belong to, along with some of my fellow ham radio club members. NOTE: even though it is slightly dated, you can make sure to download & install the specific versions mentioned in the tutorial, which should allow you to make it all the way thru. Once you are comfortable, you can upgrade everything to the latest & get the full benefit of all of the features in the current version of KiCAD (e.g. built-in routing instead of having to use an external utility router, etc.). Just be aware that they seem to be constantly changing their library management scheme, so upgrading could be very painful . . . make sure to upgrade AFTER you've become comfortable & have a good solid understanding !!

    As for PCB production, I have used OshPark for all of my boards. They are located in the US & average somewhere around a 7-day turnaround. They can be slightly more expensive than other options, but I believe the extra cost is well worth it. You could go with a PCB production house outside of the US. You might get quicker turnaround & cheaper price, but for me personally, my experience with OshPark is that I don't have to worry about quality, I don't have to worry about heavy-metal contamination, & I'm very happy with the results from their facility.

    I have no experience with metal fabrication, but I do use my 3D-printer extensively for making custom-designed cases for many of my hobby projects. I personally use ViaCAD to do my 3D design/drawing & have found it to be very capable. There are plenty of free 3D CAD tools that you can play with to see if you can find one that you like.

    I recognize that this is a Teensy forum, but quite a few members are using KiCAD to produce their own custom Teensy-based products. Feel free to ask any other questions & if we find the need to get too deep into any details, we can always take this discussion offline.

    Good luck & have fun !!

    Mark J Culross
    KD5RXT

  4. #4
    Senior Member+ KurtE's Avatar
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    I use Diptrace for the stuff I do. Again this is only for my own usage and like you typically never need many of any one board as I usually find something I want to change anyway...

    As mentioned PCBWay works well.

    For some smaller boards, I often use OSHPark (same one that PJRC uses for prototypes and the like, with the purple boards. I have also used Seeedstudio and a couple of others.

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    Thanks! I have not tried eagle, yet. I downloaded kicad but could not figure how where to begin... I am sure CAD, like all other tech things, is something we talk about like there's a universal workflow, but I bet every team uses it differently.

  6. #6
    Senior Member manicksan's Avatar
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    I don't think PDF is not used.
    But Gerber files are as they contains all layers
    For example: top text, top solder mask, top copper, and drill holes, multiple internal copper layers, bottom layers as same as the top ones.
    So there is generally generated a lot of files, that need to be sent to the PCB fabrication.

  7. #7
    Senior Member brtaylor's Avatar
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    I tried both Eagle and KiCAD and found them both equally unintuitive, so I learned KiCAD since it is open source and doesn't have restrictions on the number of layers. Having learned it, it really does become an easy tool to use with a ton of keyboard shortcuts for operations that make designing boards very quick. Highly recommend going the KiCAD route since it will grow with you if you want to keep designing boards.

    OSH Park is excellent for low cost PCB manufacturing in the US. Especially considering that their specs / tolerances are really good for the price. Their lead-times are running kind of long right now.

    I've also used Sunstone Circuits a bunch, but the cost is a lot higher and it's a sliding cost scale based on the tolerances needed for your design. For PCB assembly, I've done in-house reflow and used Screaming Circuits when the boards get beyond my capabilities. Sunstone Circuits and Screaming Circuits are geared towards professional boards, rather than hobby work, and the costs reflect that.

    Regarding enclosures, there are a bunch of standard sizes that you could design to, check digikey for some options. Otherwise, I've used SD3D for 3D printing and 3D hubs for CNC machining. I've always been a little dissapointed in SD3D's print quality, but I'm not sure if it's them or just what's to be expected from 3D printing. 3D hubs has blown me away and their work is outstanding.

    For PCB manufacturing, you'll typically upload a set of gerber files that the 2D CAD program generates that specify the different board layers. SD3D and 3D Hubs take STL or STEP files from your 3D CAD program. Assembly houses, like Screaming Circuits, need position files (specifying the positions of all of the board components relative to a reference point) generated from the 2D CAD program along with a Bill of Materials specifying the chip that is placed at each position. Sometimes they also need assembly drawings showing the component's general position on the PCB as a means to check the position file and the component orientation.

    Also, highly recommend OctoPart for finding which suppliers have a component in stock. Search by the manufacturers part number and it will show stock at digikey, mouser, and smaller suppliers. Also there are a ton of sites that you can sign up for that will let you search by manufacturer's part number and pull up 2D CAD components (footprints and symbols) and 3D CAD models for that part. It can be a really quick way forward, but be sure to check footprints for accuracy - I've noticed some of them miss design layers or are completely garbage. Unless it's a quick prototype, I'm typically drawing all of the footprints myself to make sure that everything is in agreement with the manufacturer's specs.

  8. #8
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    Hi Ben,
    I've used JLCPCB for PCBs. They are very good value and I've never had any problems with quality. The minimum order quantity is 5. I've used EasyEDA (online) for design - it's relatively easy to use. Ordering from JLCPCB from within EasyEDA is very straightforward - it will upload the Gerber files for you.
    JLCPCB will also do surface mount assembly - limited to components they stock, but it looks like good value. I haven't used that service yet, but I probably will soon,

    All the best,
    Alan


    JLCPCB will also do assembly of surface mount components (but only ones they stock and only on one side of a board). I haven't used that facility yet, but the ordering process seems to be straightforward.

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    If use use Eagle then Sparkfun have a useful gerber-generator CAM script for it, https://github.com/sparkfun/SparkFun...ree/master/cam

    Some fab houses will accept Eagle .brd files direct (I think OSHPark is an example) which is easier.

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    Quote Originally Posted by blakeAlbion View Post
    Along the same lines, I don't have anything like a machine shop. No CNC for me. I don't even have Baby's First Drill Press, or a mitre saw to make nice corners for my enclosures. (would I like a 3D printer? sure... maybe some day) So, same basic question here: If I need a customized enclosure, or even just a sheet of aluminum with some through-hole controls, what do I need to provide to a vendor so they will be able to do what I need? I have never made a mechanical diagram in my life. Flunked machine shop as a kid. My designs had holes worn in them from all the eraser use.
    DXF file format is typically used for 2D CAD, such as laser cutters and the like, so that's a candidate.
    The open source InkScape tool does SVG and can export to DXF and various other file formats.

    I've just been learning OpenSCAD (recommended!) and it also can export 2D stuff to DXF by the look of the menus (not tried it).

  11. #11
    Senior Member PaulS's Avatar
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    Quote Originally Posted by MarkT View Post
    Some fab houses will accept Eagle .brd files direct
    PCBway also does. No need to generate Gerbers.

    Paul

  12. #12
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    Quote Originally Posted by MarkT View Post
    Some fab houses will accept Eagle .brd files direct (I think OSHPark is an example) which is easier.
    Likewise, I forgot to mention in my earlier post that OSHPark accepts KiCAD files directly . . . no need for Gerbers there as well.

    Mark J Culross
    KD5RXT

  13. #13
    Senior Member brtaylor's Avatar
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    I mean, generating gerbers from KiCAD is as simple as clicking "file" -> "plot" in the menu and selecting a destination folder for them to be printed into.

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