You are correct. IPC wants you to pay for that standard, regardless if you get a hard copy or download it. Generally, it�s pretty boring stuff for production types. [Although, you will recognize some of the goofy things your designers have done to you.] Design types should get it tattooed to their bodies. On that note, what a surprise it would be if your design types already had a copy that you could borrow. [While you�re rooting around the design library, you may be able to find D-275, as an alternative. 2221 and 2222 replaced D-275 for rigid organic boards in March 1998.]
I appreciate what you�re saying about buying specifications. My boss [the owner of a previous company where I worked] felt IPC-A-610A was fine and would not buy Rev B, when it came-out. So, everyone in operations chipped-in to buy the new standards. So, he ended-up buying Rev B to save face, blaming me for his lack of fore-sight, and being too lazy to take the time to understand the business; and developed an unvarnished dislike for my internal organs. He�d be scratching, adjusting his toupee, and going-off on something eruther about "blue tick hounds, hunting-down, treeing, and killing a Yankee". And me being a Redbone fan [dang Blues er so cold nosed, anywho], I never could get a fix on what he was mumbling about. Some of which may help explain why that company is out-of-business.
Consider this: * Many fabs publish on-line "PCB Fabrication Guidelines". Do a net search, download some, and use the portions of each that you like. Hadco's was particularly good, as I recall. * Discard all of your notes on your fabrication drawings and just note "According to IPC-2221, Generic Standard On Printed Board Design and IPC-2222, Sectional Design Standard For Printed Board For Organic Printed Boards unless otherwise noted." [Then tell your boss you have to buy the standards, because they�re written into the fab drawings.] * IPC-2221 says something like ... For edge connectors and areas not to be soldered: nickel - 2.5um min [Class 2 & 3]. For edge connectors and areas not to be soldered: gold - 0.8um min [Class 2], 1.3um min [Class 3]. [Yagot me why there would be a difference in the gold for the two classes. More must be better!!!]
One, hopefully, final point: Think about leaving things just the way they are right now. Move on to something that�s broken. You will not save very much money messing around on this. In fact, you�ll probably not even recover the cost of the time you�ve spent so far. [Of course that assumes you earn the same level of chicken scratchings that I do, which is probably a reasonable assumption given your earlier comments.] And it may even end-up costing more, once your fab reprices your board, as part of your drill to determine the wonderfulness of reducing the gold on the board fingers.
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