Electronics Forum | Wed Feb 23 16:49:08 EST 2000 | Dave F
John we paced through the same question recently. Both automatic dispensers and printers can be used to deposit SMT adhesive or solder paste on substrates with a relatively high component density. Dispensers are superior to printers in terms of exa
Electronics Forum | Mon Sep 21 08:14:14 EDT 1998 | Steve Gregory
| Hello: | I would like to know what causes tombstombing and how can it be prevented? | Thx. | Nichol Hi Nichol! A tombstone happens when solder doesn't wet equally on both terminations during reflow...now why that happens can be found by looking at
Electronics Forum | Mon Jan 17 21:01:21 EST 2000 | Dave F
Dennis: On your BGAs: * Never seen voids any place other than the top ... lower density stuff rises. * Our spec on voids says: 1 Voids 1a Voids in soldered balls shall be less than 20% of the diameter of the solder ball. 1b No void shall sho
Electronics Forum | Mon Jan 27 12:27:03 EST 2003 | ksfacinelli
We have an assembly that requires a number of high density connectors to be placed after SMD. The process will not allow a normal wave solder setup due to the population of SMD comps. We cannot use a selective solder pallet due to profiles. We are
Electronics Forum | Mon Sep 21 01:57:55 EDT 2009 | kaz
Hello All, My first visit here. I own and operate a small Industrial & Consumer Electronics Service Shop. There is more and more modules with high density fine pitch SMDs that we cannot handle. We bought PACE ThermoFlow BGA SMD station with a bunch o
Electronics Forum | Mon Jan 13 18:22:55 EST 2003 | davef
100 sec) and decrease reflow temp to 205C. * Understand that voids are primarily process indicators. There is experimental evidence that voids retard crack propagation locally around the void on a temporary basis. There is no standard, IPC or otherw
Electronics Forum | Sat Jan 06 21:56:54 EST 2001 | Greenman
While solder paste height is one possible process indicator, the other guys are right on the money - volume is key. One way to study overall paste volume is to measure every single pad, using a 3D laser analysis (see you next week for board 2)... OR
Electronics Forum | Thu Apr 27 21:04:33 EDT 2000 | Dave F
Ron: Good news: Nicolet makes excellent machines. Bad news: I�m unaware of a machine with the capabilities you seek. * X-ray machines lack of resolution needed in relation to the crack geometries encountered within a high density single material.
Electronics Forum | Wed Jun 12 08:24:03 EDT 2002 | davef
Tough. 0402 capacitors are more prone to tomb stoning than resistors. Tailor your process to the 0402 and let the other stuff fall where it falls. Search the fine SMTnet archives for discussion on tomb stoning. Consider: * Changing paste. * Apply
Electronics Forum | Mon Aug 02 18:46:33 EDT 1999 | Jim Blankenhorn
| | Has anyone done the research on BGA pad size? suppose I have a 0.030" diameter pad as recommended pad size from the spec, what will the minimum pad size allowed? We are laying out a high density board. | | If you know what component your'e going
