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Article #778Re: Why don't they mark SMD caps?
From: Michael A. Terrell
Date: Thu, 23 Jul 2009 14:58
Date: Thu, 23 Jul 2009 14:58
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2940 bytes
"David L. Jones" wrote: > > An interesting question was posted on another forum: > "can you get (ceramic) SMD caps (1206,0805 etc) with the values printed on > them?". > > My first response was that I've very rarely seen this (like maybe once), and > while it is possible (see > http://www.synrad.com/search_apps/application_briefs/117-2.htm), you > basically can't get labeled ones, they are almost always without markings. > > It got me to thinking, why is it so? > My guess would be that it's due to the surface finish (or lack thereof) on > ceramic capacitors, and/or the delicate nature of their multi-layer > construction means they could be more easily damaged or properties altered > by the process. > As opposed to most SMD resistors that have a coating on them which would > allow for easy and accurate printing using various technologies. > > Any know the real reason(s) why ceramic SMD caps don't have markings? Most of what we used were marked with a two character code. The cheaper suppliers were unmarked. I have a javascript I wrote to let production workers ID SMD caps. Of course we were building equipment for NASA, NOAA, the ESA and military, so they didn't mind the fraction of a cent more per cap to pay for markings. I'll try to upload the zipped script files if you'd like to see them. -- You can't have a sense of humor, if you have no sense!
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