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Perforating a large PCB with 2.5mm holes

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22件のコメント

  • Boss .

    The powerplane will automatically have clearance from all pads that are not connected to it. The gap is set in the design technology and as the copper pour is a "shape", it is the pad to shape spacing that sets the gap. The pads that connect to the ground plane will have thermal spokes and spacing as set inth e "Rules" tab.



    If you don't want copper on any other layer, just don't place any.

    From your description you should have set up a 4 layer pcb with one layer defined as a powerplane.


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  • erez shadach

    Thanks for your quick response Boss, I'm trying to "read between the lines" of your reply as I'm a new comer here and some of the terms you use are still not clear to me. I am reading now through the "getting started" menu to try and link between your "straight to the point" reply and DesignSpark's general explanations. Do you know if there is a way to quickly duplicate the holes (once I find out how to make one)? I need hundreds of them. Thanks again!

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  • Boss .

    Hi Erez, you are welcome.

    Some points... You can launch the Design Technology using <Shift +T>

    4 Layer boards are more expensive than 2 layers, check for your requirements you actually require 4 layers. The copper on the powerplane will fill the gaps between the pads and as through hole pads have the same footprint on each layer the area of the powerplane will be the same as putting a copper pour on the top and bottom layers, so if this is a prototyping PCB that may be as good. The copper pour on the outer layers will be covered by solder resist. So just a thought.

    Some manufactures charge a premium if the number of holes is large, so do check when selecting a supplier.

    From what I understand of your project the easiest way to get an array of holes on a fixed pitch is select a grid that matches the pitch. Then place say 2 pads (or more as they will snap to the grid) now with nothing selected from the tools (press <ESC> to cancel out from the current tool) use the mouse to select the placed pads i.e. draw a selection box around/through them and they will become highlighted (white). Now use CTRL+C to copy and CTRL+V to paste and you can move them around and left click to place.
    You can then select a larger number of pads and repeat. Do this for complete rows or blocks as the area grows.

    The" hole" you mention is actually a pad. This can be selected from the tool bar and once the mouse is moved over the PCB a white pad shape will appear, press "S" and you can select a different Style or create a new one with the hole size and copper pad size defined, you do require " plated" for the through hole pad.

    One tip is the PCB can give a force appearance of size on the screen compared to 'real life', so do ensure the pad size is what you want!

     

     

     

     

     

     

     

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  • Richard Caldwell

    You can use vias for you holes.  Here is a short screen capture video how I do multi holes.

    https://www.dropbox.com/s/ih9e7g9b45lt9xz/Multi%20Holes.avi?dl=0 

     

    P.S.

    I just noticed Boss replay, about using Pads instead of VIAs. My method should work with either Pad or Via.

     

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  • Boss .

    @Richard, thanks for this I have NEVER used the "Add multiple items"! I had no idea it existed... even having used DSPCB since V2...  Thanks again.

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  • Richard Caldwell

    Your welcome :-)

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  • Brad Levy

    The Add Multiple Items context menu choice can be used with components as well as pads and vias.

    The technique Boss describes is good to remember when you want to make multiple copies of something other than a particular component, pad, or via.

    For example, I've used it to make a panel of 100 small (0.7 x 0.7 inch) double sided surface mount boards, each board having fifteen components and associated traces and vias. The panel is v-scored on the row and column boundaries of the array by the PCB vendor. Then the panel goes through automated component insertion and reflow soldering. After inspection, the panel is separated into the 100 individual boards, which then go into the end product.

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  • erez shadach

    Thanks for your comments guys!

    Boss, will the difference between "Pad Width" and "Hole Size" result in the "clearance around holes" that I need as they go through the inner copper layer?

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  • Boss .

    The second link on this page may help with many topics

    https://designspark.zendesk.com/hc/en-us/articles/115004904249-Is-there-a-book-about-DesignSpark-PCB-

    Pad width is the diameter of the copper for a round pad. Here I created a pad of 2mm width and hole of 1mm

    I did a copper pour around the pad and that is a gap of 0.254mm as set in the Design Tech I posted earlier.

    The best way is to explore, place some pads and use the measure tool to see the results.

     

    Hope that helps.

     

     

     

     

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  • Richard Caldwell

    erez shadach 

    I think you are confusing Pads/Vias and a Copper Pour. These are two different operations. Here is another short screen capture that shows what Boss is talking about.

    https://www.dropbox.com/s/ih9e7g9b45lt9xz/Multi%20Holes.avi?dl=0 

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  • erez shadach

    Richard you are right, and thanks a lot for the video!!! I'll study it tonight.

    Boss, thanks for the link to the PCB Guidebook, I'll read it.

    Life is easier thanks to you guys!

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  • erez shadach

    I just realized that the max PCB size is 1m x 1m while I need 1.1m X 0.5m.

    Do you have any idea as to what I can do about it?

    Thanks!

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  • Richard Caldwell


    Your welcome erez :-)

     

    WOW that's a extremely large PCB. That limit is the max most PCB houses can handle. So I think you might have to do a total redesign of your entire project around a PCB that within these limits. Here a screen shot that shows the max PCB size that my PCB house can handle.

     

     

    May I be so bold to ask what is your project that needs such a large PCB?

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  • Boss .

    "wait for Brad!" he proposed a method which used 1/2 scale parts in the PCB design and x2 for scaling the Gerber output some time ago. If the board doesn't use many components which will all require special half scale components in the library, it may be possible, but note Richards warnings on manufacturing size and expect the PCB to suffer from distortions if it can be produced. 

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  • Richard Caldwell

    I guess I am missing something. erez  wants a very large PCB board with a lot of holes and a Ground plane with out any components!!!!!!!!!!!!!!!!!!! What would this type of PCB be used for.

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  • Boss .

    @Richard, I'm as intrigued as you are!

    Thoughts...

    RF screen for uWaves? As it may have internal layer shield is probably my best guess, but expect 'way off'!

    Mechanical location plate? I did this once on a much smaller scale with less holes on a robot location base.

    Erez, any clues or answers?

     

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  • Richard Caldwell

    @Boss if so then why not use a Faraday Cage, made with copper screen where the mesh would be tuned to the frequency(s) that is needed to be filter out. Using copper screen you could make the cage the size of a foot ball field, not to mention the cost and time need to design a PCB.

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  • erez shadach

    Thanks guys for your concern!

    I actually wanted it to be 2m x 0.5m, but the largest I was offered so far was 1.1m x 0.5m by PCBgogo.

    Boss, you said that the PCB may suffer from distortions, I hope you didn't mean warp, as warping would render it useless for my project. It must be perfectly flat, and I thought that the process of drilling (as opposed to punching) would satisfy that need.

    And now I'll tell you what it's for: An electrostatic loudspeaker. Each speaker needs two such PCB's, between which a thin diaphragm vibrates, and through the holes escapes the sound.

    So what about "wait for Brad!"? I wanna hear more about his method...

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  • Richard Caldwell

    OH OK

    May I suggest some thing that might be better then a PCB. Make a sandwich of fiberglass/carbon fiber and a copper sheet. Just glue a fiberglass/carbon fiber panel on the top and bottom of the copper sheet (with a tab to connect it to GND). Then using a dill press you drill the required holes by hand or computer control drill. If the holes needs to plate you could send it a plating company. .

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  • erez shadach

    Interesting idea Richard, thanks, but I need a copper clearance around the hole(s) to avoid the spark.

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  • Brad Levy

    I think the technique I thought of in the past, of scaling the design, would work, I have several thoughts.

    - If I did use that technique, I'd probably scale by a factor of ten rather than a factor of two.  It makes the math easier.

    - The board is likely to be quite expensive, due to large number of holes as well as beyond-normal size.

    - Make sure you factor in what voltage you plan to be applying to the "plates", and calculate how much clearance you need between the holes and the copper plane to prevent arcing. The breakdown voltage of the board material is not infinite, and is also affected by moisture/humidity. Here is a web thread as a starting point, that mentions other resources as well: https://electronics.stackexchange.com/questions/211025/high-voltage-multilayer-pcb

    I'd  consider other non-pcb approaches. Coating a drilled or punched sheet with insulating varnish could solve the arcing problem without resorting to PCB material. If you are concerned about flatness, you might consider a rigid larger-spacing support grid behind the copper grid, to provide additional stiffness to the copper, while still not blocking air movement.

    Your don't necessarily need copper as your main material. Electrostatics are high-voltage, low current. So ultra-low resistance isn't as critical. In addition, the large 2-D plane nature of your conductor will keep resistance fairly low, compared to long small-cross-section wires.

    Good luck. Some people I worked with in the past later developed and market a well-respected line electrostatic speakers. (I wasn't involved in the design, though, so that doesn't necessarily lend extra credence to my advice.)

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  • erez shadach

    Hi Brad, thanks for your comments.

    "Make sure you factor in what voltage you plan to be applying to the "plates", and calculate how much clearance you need between the holes and the copper plane to prevent arcing."
    Reply: My main worry is that the copper would not be sealed when "looked at" from within the hole (put any clearance aside for the moment) and thus would be "spark approachable".

    "Coating a drilled or punched sheet with insulating varnish could solve the arcing problem"
    Reply: Bin there, done that, and it partly solves the arcing problem, but unreliably. 

    "If you are concerned about flatness, you might consider a rigid larger-spacing support grid behind the copper grid, to provide additional stiffness"
    Reply: It's already in the pipe line for the PCB project, in case it fails to be rigid enough.

    Question: Any tips regarding the 1:10 scaling process?

    Thanks again!

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