Solderability Testing

Lflt-versuch, m. blowpipe test soldering test, -wasser, n. soldering fluid, -zinn, n. soldering tin. 

The alchemist may earn a scanty livelihood by the production of medicaments or cosmetics, or he may use his art, as very many do, to carry on the business of a coiner. But the true searcher after the Stone which is to metamorphose all base metals into gold, converts only farms, goods and patrimonies into ashes and smoke." He added somewhat grudgingly, "Nevertheless, I do not deny that to this art many excellent inventions owe their origin. Hence we have the discovery of azure, cinnabar, minium, purple, that which is called musical gold, and other colors. Hence we derive the knowledge of brass and mixed metals, solders, tests and precipitants."... 

Figure 2. Solder test specimens two-inch immersion for five...

An aqueous chemical pretreatment for unfilled polyetherimide substrates is described. The process includes the use of a chemical impregnator to increase the mechanical adhesion component and avoid metal lymer delamination during the initial electroless metallization step. Excellent adhesion was achieved for copper or nickel to both injection-molded plaques and extruded films. The metalA>olymer bond was found to be durable in thermal environments (dry and moist) as well as in simulated solder tests. Failure occurred within the polymer substrate during 90° peel testing. The process was found to be applicable to filled substrates as welt. 

The adhesion of specimens subjected to environmental exposure tests was evaluated prior to and subsequent to the contact. Wet thermal shock testing consisted of five cycles each for IS minutes in boiling water and 2 minutes in ice water. The maximum transfer time between the two baths was 30 seconds. Thermal and temperature/humidity exposures were performed in controlled atmosphere chambers for 200 hours. Simulated solder tests comprised immersing the test. specimen in a silicone oil followed by solder flotation. The solder temperature varied from 232 to 288 C and the contact time was S or 10 seconds. In some cases, two flotations were performed on the same sample. The effect of a heat treatment at 135 C prior to solder testing was examined the heat treatment time varied from 0 to 16 hours. ... 

If the reactive blending is stopped at an intermediate stage, the micelles and the shrunken particles coexist and a bimodal particle distribution is realized, as shown in Fig. 8.39. In the case of Fig. 8.39, PA-6 was mixed with polyethylene (PE) modified with a small amount of MAH (0.1 wt%) and glycidyl methaciylate (3-12 wt%), at a 70/30 (PA/PE) blend ratio. The bimodal system can be easily crosslinked by electron beam irradiation at a low dose level, the same as that used for neat PE (Pan et al. 2002). The crosslinked PA/PE alloy shows good heat resistance in a lead-free solder test thus, it may be applied in making construction parts with melt-down resistance in fires, e.g., a window frame. 

If done as part of the electronic design automation (EDA) process using appropriate electronic computer-aided design (ECAD) software, the software wiU automatically assign copper directions to each component footprint, as weU as appropriate coordinates and dimensions. These may need adjustment based on considerations related to wave soldering, test points, RE, power and EMI/RFI issues, and board production limitations. Allowing the software to select 5-mil traces when the board production facility to be used can only reliably do 8-mil traces would be inappropriate. Likewise, the solder mask patterns must be governed by the production capabilities. 

Float solder test This test includes prebaking and flux, using a 5 to 20 sec. float in a solder pot (60 40) at 550°F, followed by cross-sectioning for evaluation. 

TABLE 42.1 Solderability Test Methods with Accept/Reject Criteria... 

When a lead, component, or PCB is immersed into solder during a solderability test, the following can be derived from the component solder interface Equation 42.1... 

Solderability testing by dip and look methods do not meet this minimum requirement. The science of GR R has since evolved into Measurement System Analysis (MSA), where GR R is only one part of a system that evaluates the total measurement capability. MSA is an experimental and mathematical method of determining how much the variation within the measurement process contributes to overall process variability. It takes into account... 

AH of these requirements can be attributed to solderability testing, even though at first glance it would appear to have nothing to do with it. Being able to test to a protocol that meets the previous requirements provides useable data for process development and improvement and hopefully wHl facUitate a much shorter development time than might otherwise be the case. 

FIGURE 42.6 Possible outputs from a solderability test using a wetting balance. 

INTERPRETING THE RESULTS WETTING BALANCE SOLDERABILITY TESTING... 

It is very important that the solderability test, including any stressing that may be imparted on the deposit, be representative of the failure mode that the surface finish finally succumbs to naturally over time.The use of steam to stress a deposit other than a lead-bearing one is not to be used the recommended stressing is eight hours of exposure to 72°C/85 percent R.H. 

PCB Surface Finishes and Solderability Testing for Plated Through Holes... 

J-STD-002, Solderability Tests for Component Leads, Terminations, Lugs, Terminals, and Wires. This standard prescribes the recommended test methods, defect definitions, acceptance criteria, and illustrations for assessing the solderabihty of electronic component leads, terminations, solid wire, stranded wire, lugs, and tabs. 

J-STD-003, Solderability Tests for Printed Boards. J-STD- 003, Solderability Tests for Printed Boards, was released in April 1992 to complement the requirements of J-STD-001. This standard prescribes the recommended test methods, defect definitions, and Ulnstrations for assessing the solderability of printed board surface conductors, attachment lands, and plated-through holes. 

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