Two pcb questions...

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Hi Everyone,

I've got two PCB questions:

Does anyone make a PCB (or tool) that has various sized plated holes in it - for example, 20mil, 22mil, 24mil in a range of sizes from 2-70 or something like this.

Also, I'm thinking of trying some SMD stuff and I noticed many datasheets include a recommended layout showing where the pads should be, how big, etc. My question is - are these types of layouts optimized for automated soldering such as baking, etc? If I were going to solder a few by hand, should the pads be sized a little larger in a direction that doesn't matter to make soldering easier?

Thanks,

Alan

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Those footprints provided in data sheets are intended for reflow soldering by a machine. QFPs and the like are OK for manual soldering, but I extend the pads a little for devices in QFN packages. It makes them much easier to solder by hand.

Leon Heller G1HSM

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Leon wrote:

Quote:
I extend the pads a little

Good idea. I gave those a name: Solder Assist Slab, or SAS ;)

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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Also, I put a large via in the central pad for the QFN. After soldering the side contacts I heat the via with a large tip and feed solder into it.

Leon Heller G1HSM

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Alan,

Entech Electronics (Australian company) makes this tool. Double sided.

Cheers,

Ross

Attachment(s): 

Ross McKenzie ValuSoft Melbourne Australia

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Wow, you can make newspaper print in PCB holes.

The Dark Boxes are coming.

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Hi Ross,

valusoft wrote:
Alan,
Entech Electronics (Australian company) makes this tool. Double sided.
Cheers,
Ross

Yes - that is exactly what I was thinking. Do they still sell it? I don't see it on their website...

Thanks,

Alan

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They have it as a promotional tool. Ask nicely and they might send you one.

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This may not be as useful as what Ross suggested, but I recalled Sparkfun selling a PCB somewhat like what you're looking for. (Digging around...) Yes, here it is:

Eagle Text Reference Board
US$4.95
sku: PRT-08754

Sparkfun website wrote:
Description: If you've ever played with Eagle PCB, you know that silk screen indicators are one of the most important aspects of your layout. We created this board to illustrate various text sizes and ratios (text width). You may use size 0.020 text with a ratio of 8% on your PCB layout, but as the reference board demonstrates, you really can't read it. We also included various drill sizes and trace widths but they are not completely accurate - the manufacturer increased the really small trace widths to avoid DRC violations. This is a great board to quickly determine the best size and ratio for text, drill sizes, and trace widths when creating your next design.

Dimensions: 2.2x3"

Take a close look at the expanded image files (Side 1 and Side 2). On Side 1 you'll see a demonstration of various annular diameters.

Also, if it's more useful than the actual PCB, EAGLE '.brd' and Gerber/drill files are provided in the "Eagle Source Files" link on that page.

HTH....