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Electronics Forum / CAD / April 2005PCB holes overlapping
Is this generally acceptable? I want to overlap two of 0.136" holes by about 0.024" in several places. They are plated with no electrical function. Thanks! Best regards, Spehro Pefhany  Signature"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com > Is this generally acceptable? I want to overlap two of 0.136" holes by > about 0.024" in several places. They are plated with no electrical [quoted text clipped - 4 lines] > Best regards, > Spehro Pefhany One supplier I use for prototype PCBs (PCB-Pool)assumes that overlapping holes are slots to be routed. I don't think that PCB manufacturers would like actual overlapping holes as they might break their drills. Leon SignatureLeon Heller http://www.geocities.com/leon_heller >Is this generally acceptable? I want to overlap two of 0.136" holes by >about 0.024" in several places. They are plated with no electrical [quoted text clipped - 4 lines] >Best regards, >Spehro Pefhany Because the holes rather large compared to overlap you can probably get away with it. Check with your board manufacturer. SignatureBoris Mohar Regards, Boris Mohar Got Knock? - see: Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca Spehro, Do you want a slot or a figure eight shape? I always use one of either two methods for such things. 1) I use a unique hole size for one pad, 1 - 5mils, something they cannot attempt to drill. Then do a note referencing that drill size and a small drawing outlining the shape and dimensions based upon the unique hole size being the center of one of your lobes. 2) If it is a slot, then I usually use a mechanical layer to draw the shape I want in the correct location and orientation. Then reference it in your notes telling the fabricator that this shape is desired and that it is plated. Make sure there is some common reference between layers so that a Gerber set aligns the detail precisely where you want it and in the correct orientation on the PCB. I have also give these details on multiple layers with the lines actually including an offset for appropriate router bit diameters that I know the fabricator has. Theses layers are then just a router centerline path for them to program into their machine. SignatureSincerely, Brad Velander > Is this generally acceptable? I want to overlap two of 0.136" holes by > about 0.024" in several places. They are plated with no electrical [quoted text clipped - 4 lines] > Best regards, > Spehro Pefhany >Spehro, > Do you want a slot or a figure eight shape? Figure 8. I have 16 connectors with snap-in fingers on either side that I need to mount as close together as practical. > I always use one of either two methods for such things. >1) I use a unique hole size for one pad, 1 - 5mils, something >they cannot attempt to drill. Then do a note referencing that >drill size and a small drawing outlining the shape and dimensions >based upon the unique hole size being the center of one of your >lobes. What's the advantage of that? To draw attention to it so that they cannot "fix" it? >2) If it is a slot, then I usually use a mechanical layer to >draw the shape I want in the correct location and orientation. [quoted text clipped - 8 lines] >just a router centerline path for them to program into their >machine. Best regards, Spehro Pefhany Signature"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com Spehro, Yes the advantage is that it is a hole they just cannot drill if they have missed it's true function through the notes. The use of a hole also gives you (and them) one precise location relative to the rest of the database. So the figure 8 takes one snap in lead from two connectors and you just wanted them close so that they broke into each others holes? I am now wondering what type of connector your talking about and if maybe a short slot on the other axis would be better (a straight edge instead of the round edge). The connector doesn't fit over the figure eight I would guess, unless it doesn't connect electrically to the board at least. SignatureSincerely, Brad Velander > >Spehro, > > Do you want a slot or a figure eight shape? [quoted text clipped - 14 lines] > Best regards, > Spehro Pefhany >Spehro, > Yes the advantage is that it is a hole they just cannot drill [quoted text clipped - 8 lines] >connector doesn't fit over the figure eight I would guess, unless >it doesn't connect electrically to the board at least. It doesn't connect electrically (plastic snaps), and the legs are not round, they are rectangular. Ideally slots would be punched, but the volume isn't there. Best regards, Spehro Pefhany Signature"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com Spehro, Yeah, I was suspicious that the round holes probably weren't the optimum hole for anything that snapped in. Simply because most snap in parts would only fully catch at the outside corners rather than along the full length of the snap face. Would short routed slots not be better? Slightly longer than the length of the snap face. Then the whole face of the snap feature can bear the loading instead of just the corners. Typically you can get 0.032", 0.625" or 0.093" routing diameters from most fabricators. Other sizes would not be as common, even 0.032" is not so common with a lot of them. SignatureSincerely, Brad Velander > On Wed, 27 Apr 2005 03:46:12 GMT, the renowned "Brad Velander" > [quoted text clipped - 4 lines] > Best regards, > Spehro Pefhany >Spehro, > Yeah, I was suspicious that the round holes probably weren't [quoted text clipped - 7 lines] >from most fabricators. Other sizes would not be as common, even >0.032" is not so common with a lot of them. That's a very good idea. I'll ask when the final revision is done. Thanks! Best regards, Spehro Pefhany Signature"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com >Is this generally acceptable? I want to overlap two of 0.136" holes by >about 0.024" in several places. They are plated with no electrical >function. Hi Spehro, Yes totally acceptable at the size in question. I would be amazed if any manufacturer found it a problem. Only side effect of the double drill that I can think off would be the possibility of a few broken glass fibres protruding where the two holes intersect. SignatureRoger M Unwin P+M Services (R) Ltd Tel : 01706 815212 Fax : 01706 818636 Http://www.p-m-services.co.uk >>Is this generally acceptable? I want to overlap two of 0.136" holes by >>about 0.024" in several places. They are plated with no electrical [quoted text clipped - 5 lines] >that I can think off would be the possibility of a few broken glass >fibres protruding where the two holes intersect. Thanks! Out it goes. ;-) Best regards, Spehro Pefhany Signature"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
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