🚀 go-pugleaf

On Thu, 23 Jul 2009 20:16:44 -0500, krw <krw@att.bizzzzzzzzzzz> wrote:

>On Thu, 23 Jul 2009 17:47:08 -0700, Archimedes' Lever
><OneBigLever@InfiniteSeries.Org> wrote:
>
>>On Thu, 23 Jul 2009 10:58:49 -0400, "Michael A. Terrell"
>><mike.terrell@earthlink.net> wrote:
>>
>>>   Most of what we used were marked with a two character code.  The
>>>cheaper suppliers were unmarked.
>>
>>  Wrong again.  Markings fell out of vogue as part size decreased to the
>>point where it was labor intensive to even examine the marking.
>
>Then why are they still there on resistors of the same size, DimBulb?


  Because resistors are fired glazed parts to seal the resistance medium
from moisture, and that can have legible letters included.  If chip caps
had an outer glaze or epoxy slab on them, lettering could easily be
added.  The industry has found better performance from uncoated MCCs, and
fire glazing is out of the question as the layer terminations are
thermally sensitive.

 The chip cap markings, even on the larger form factor parts, was a very
fuzzy, out of focus character set, beneath the actual first surface of
the mlcc.  Maybe laser etched or it is a very very thin ink.  Some were
surface marked, but most were submerged. On a smaller form factor, that
becomes very hard to see, and adds labor to inspect via the marking, and
it does become harder to manufacture as well, causing more fab failures
before they even get going.

  Visual comparison with the reel is the most common and preferred method
for already installed parts. Visual comparison and testing for loose
parts.  Some can be ID'd by their 'color', which *can* indicate substrate
choice,which should be easy to note on the reel info label.  When certain
caps are a buck each (microwave SMD chip caps), and others are fractions
of a penny (El Cheapo Browno), one wants to be sure that one places the
right part in the right locations.