Quick PCB design assistance

Discussion in 'The Projects Forum' started by airplane100000, Nov 6, 2016.

  1. airplane100000

    Thread Starter Member

    Aug 2, 2016
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    I need to design a simple PCB for a battery-powered power supply. The circuit is complete and is comprised mainly of SOT-23 packages.
    The PCB should be a one layer and one sided rectangle, with all components SMD mounted.
    I have access to NI Ultiboard, and the design seems straight forward to accomplish with the exception of:

    The battery sockets - The design is to use four of coin these battery holders. I have no clue how to implement such a component into the board design software. The catalog page indicates that this product is "Available in Multisim Blue", so I suspected that it would appear in the Ultiboard database, but it does not. I have no experience with Ultiboard or any other board design software, and following several hours of attempting to resolve the issue I have had no success. I attempted to draw copper circles (as battery contacts) and then place SMD pads (for attaching the holders), but the software does not let you place pads unless you place a component from the database (as far as I know), and it does not seem to allow you to connect the circles.

    It would be of great help if anybody could give advise, either as to how Ultiboard can be used to achieve this, or recommend another software in which such a task can be readily achieved.
    -Thank you all
     
  2. jpanhalt

    Expert

    Jan 18, 2008
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    I do not use NI Ultiboard, but I would be extremely surprised if that program did not allow you to make a new component and add it to the library. Is there a "open library" dialog or its equivalent?

    John
     
  3. airplane100000

    Thread Starter Member

    Aug 2, 2016
    68
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    Well it does have a fairly intuitive part wizard, but what I need is a non standard component. I hoped you could simply add pads, but apparently you can't...
    Also I still can't understand how to create the circular etchings for the battery contacts with the board.
     
  4. jpanhalt

    Expert

    Jan 18, 2008
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    I deal with Eagle, so there may be something lost in translation. A library part is made of a symbol and a package that are combined (e.g., the pins are connected the pads) to make a device, which is what one finds in a library. Have you looked for "pins" which you add to the symbol? Pads are part of the package. You probably need to make an entire device, as many of the very useful functions of such software include ERC and DRC checks, so they will not allow a component to be added that is not a complete device (some exceptions apply).

    Here is an example of a battery "symbol"
    upload_2016-11-6_10-39-35.png
    And here is a package (for another symbol):
    upload_2016-11-6_10-42-37.png

    John
     
  5. airplane100000

    Thread Starter Member

    Aug 2, 2016
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    I guess I'm figuring out ways to accomplish this, although I doubt they are the ideal ones.
    One more question if anybody knows: Is it possible/acceptable to incorporate a hole into the board design? That is for instance, a small square cut out in the middle of the rectangular board. Can this be done in PCB design software, and it can it be manufactured in such a way?
     
  6. jpanhalt

    Expert

    Jan 18, 2008
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    It is done all the time. Some vendors provide plating of such hole/slots. My usual vendor does not.

    John
     
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  7. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Interior non-round holes are done by drilling a small hole, pulling out the drill bit and inserting a CNC router bit, and routing the shape. This usually increases the setup charges for the board, as the hole parameters are manually entered into the router. Because a router bit is round, you cannot get perfectly square corners; they have the radius of the router bit. The interior walls of the cutout can be plated or not. Some board shops charge more for non-plated because it involves a second trip to the CNC drill/router after the plating stage.

    ak
     
  8. jpanhalt

    Expert

    Jan 18, 2008
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    Are you certain of that sequence at all shops? My shop uses the Dimension layer for slots. That would not be in the drill file, I don't think. Maybe a corollary of that is that non-plated slots are supported and don't add much, if any, to the cost; plated slots are special.

    Also, based on the way the Dimension is cut, I am fairly certain the milling cutters used are end cutting. There is no need in that case to drill a pilot hole.

    John
     
  9. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    I agree, it's not in the drill file. That is why the dimension layer, or assembly layer, or the randomly-named "internal cutouts" layer has to be converted to CNC code by hand. Granted it is not difficult at all, with a simple rectangle taking about 5 minutes. My point was that it is not nearly as semi-automated as the drill data, so it comes at a cost. One of my board shops uses its drill table for routing, another does it on a separate machine.

    I'm not nearly as connected to purchasing as I used to be, so maybe non-plated holes are so common that cost has come down to a small surcharge or none. Pretty sure they're still a 2nd trip to the drill, but no one sends me memos anymore.

    ak
     
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  10. airplane100000

    Thread Starter Member

    Aug 2, 2016
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    Thank you all for the information. This is for a mass production board. I essentially need to incorporate a small 1cm square pre-bought PCB into my larger rectangular circuit board (one layer, one side, SMD). So I believe that my two options are to either place the smaller square (glue?) into a cutout, or two place the smaller square side by side with the larger rectangle (which would take up more space).

    The first production run will be aprox. 1000 units, and money is tight: What would be a vague estimate of the additional cost for the cutout solution (no plating), per board? Also, how difficult (or not difficult) would it be to find a manufacturer who will glue this pre-made board into my cutout? If this is not feasible for some reason, I guess I will have to reconcile with some other solution.

    Thanks!
     
  11. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Photos of what you are describing would help reduce rampant vagueness. Also, where are you?

    ak
     
  12. jpanhalt

    Expert

    Jan 18, 2008
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    If you have room for a cutout, why not just glue the smaller PCB like a backpack to the larger board?

    John
     
  13. airplane100000

    Thread Starter Member

    Aug 2, 2016
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    Was my vagueness really that rampant... (edit: I did mistakenly spell "to" as "two" :eek:)
    I have no technical images, but hope this helps:
    [​IMG]
    What do you mean when you ask where I am? I am based in the States, but production will likely take place in China.

    jpan, that I considered that, but I have to limit board height.
     
    Last edited: Nov 11, 2016
  14. jpanhalt

    Expert

    Jan 18, 2008
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    1/16" is that critical? So, make a hole and put it in the hole. Zero effect on height. Non-plated, routed holes don't cost much if anything. Of course, they don't subtract from the area cost. Putting it on the side, of course, is an option, butthat gives you an odd shaped device with a much larger circumscribed rectangular area.

    John
     
  15. airplane100000

    Thread Starter Member

    Aug 2, 2016
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    3
    Thanks.
    In this case every mm matters because it has to fit into a narrow housing.
     
  16. AnalogKid

    AAC Fanatic!

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    The internal locationwill be more hassle, but more rugged than the external one.
     
  17. airplane100000

    Thread Starter Member

    Aug 2, 2016
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    This is my first PCB design, so while I'm at it:
    Is printing a silkscreen legend necessary? Is it merely for clarity and to assist in manual soldering? Does it raise the cost?
    I'd rather my circuit design not be obvious to the consumer, so I'm thinking of avoiding printing a legend...
     
  18. jpanhalt

    Expert

    Jan 18, 2008
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    Usually, silk screen does not affect cost. Some of the very lowest cost houses charge a little extra for silk screen on the back (non component) side. While the silk screen may be of no value for computer assembly, it can be helpful for trouble shooting and QC/visual inspection.

    John
     
  19. SLK001

    Senior Member

    Nov 29, 2011
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    No, it is up to you.

    Yes.

    Most vendors include it in the cost.

    Why? Do you really think that consumers are out there just waiting to copy your design?

    If you are going to hand assemble these boards, then you'll appreciate a silk-screen. I've done boards with and without a silk-screen and I much prefer a silk-screen.
     
  20. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    If you build 1000 units, so poor sod is going to have to troubleshoot and repair at least 100 of them over the product lifetime. The main use of the legend is in maintaining the design, not manufacturing it. Robots don't need the legend; the guy with the scope does.

    ak
     
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