After the test boards had been produced, the final hole diameters were measured, and one ImSn board and one ENIG board were cross-sectioned to verify dimensions.
The cross-sectioning of two test boards (one ImSn and one ENIG) showed they had been well fabricated.
A total of 240 pins of each pin type were used in this test, which gives 40 pins for insertion and retention for each combination of hole plating (ImSn and ENIG) and hole size (min., nom., max.).
"We are proud to host IMSN
meeting and announce that this year marks the first time that the IMSN
will be holding their annual meeting in this region, as a milestone towards setting world-class practices in medication safety and following the UAE joining the network as a member in 2010.
SUPERVISION NETWORK (IMSN
), FINDINGS ON CROSS-BORDER REMEDIES, at http://www.icpen.org/imsn/cross%20border%20findings.htm (last visited Mar.
In the case of the second material, PCBs with ENIG finishes produced joints that performed as well as those with ImSn
or ImAg finishes.
In Part I, surface finishes included organic solderability preservative (OSP), electroless nickel-immersion gold (ENIG), immersion silver (ImAg) and immersion tin (ImSn).
As anticipated, ENIG finish showed complete spread even to the upper limit of the test and the ImSn showed similar behavior with only a few sites unbridged at the highest gap.
As expected, ENIG and ImSn showed full spread regardless of the aperture cropping, therefore it is suggested that assemblers currently cropping QFP aperture continue the practice when assembling onto ENIG or ImSn surface finishes.
It's an enigma being served by several candidates--some better than others--such as hot-air solder leveling (HASL--just what its acronym suggests), organic solderability preservative (OSP), electroless nickel/immersion gold (ENIG) and a couple of emerging contenders: immersion silver (ImAg) and immersion tin (ImSn).
For example, HASL is not "environmentally friendly"; OSP may not be a conductive contact surface; ENIG may not be compatible with soldermask; ImAg may have solderability shelf life issues; and ImSn may give you tin whisker problems.