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cleaned using a solvent, then fol- lowed up with a DI water cleaning process to improve the cleanliness of the assembly’s surface. Water-based cleaning and, more importantly, water-based rinsing, typically pro- duces superior cleanliness results compared to solvent processes. This fact was reiterated in IPC’s “Phase II” test results — a comparison of sol- vent vs. water-based cleaning.


Conveyor vs. Batch Cleaning


Inline (conveyorized) cleaning machines are better than batch cleaning machines. True and False. The fact is that both batch and


www.us-tech.com Debunking Urban Legends


inline technologies clean equally well. No one configuration cleans bet-


ter or worse than the other. One should choose batch or inline based on the volume of assemblies that need to be cleaned. Batch cleaning systems


are capable of cleaning vol- umes ranging from low to high. Inline cleaning mach - ines normally are associated only with high volumes. When all cost centers


Cleanliness testing system.


are accounted for, the opera- tional cost of a batch process is approximately 10-20 per- cent of the cost of an inline cleaning process. As the cleaning volume increases, the cost differential lowers.


TAKAYA CORP.


Takaya pioneered Flying Probe Test and became the worldwide standard by providing the performance, reliability, and local support to meet the demanding and varying requirements of electronics manufacturers, especially in a quick-turn environment.


APT-9411CE


Industry Standard for Most Electronics Manufactures


APT-9411SL Maximum Test Area for Large Board Applications


The cost per assembly on an inline cleaner begins to lower when the cleaning volume approaches several thousand assemblies per day. Volumes less than that generally are better suited for batch-format clean- ing processes.


Dishwashers/Glassware washers work well. False. While many batch-format cleaning machines may resemble dishwashers, dishwashers typically are not compatible with the defluxing chemicals nor are they capable of acceptable under-compo- nent penetration. Dishwashers are for dishes.


We do not need a powerful machine. The defluxing chemical lowers the surface tension, allowing adequate impingement. False. While defluxing chemicals do lower the wash solution’s surface tension and allow for improved under-component penetration, the real issue is the rinse cycle. Today’s defluxing results fall into two cate- gories: excellent and disastrous. The worst thing one can do is to partially clean an assembly. Wash solution allowed to remain on an assembly, due to inadequate rinsing, is far worse than flux being allowed to remain on an assembly. Rinse is the most critical part of a successful defluxing process. Rinse water, unlike chemical-enriched wash solu- tion, has a higher surface tension. That means the rinse water must be forced into tight spaces to effectively displace the lower surface tension wash solution. This is accomplished by forcing water through multiple nozzles that diffuse the solution into smaller water particles. The smaller the water particle, the better its abil- ity to get under tight spaces.


IPC standards state how clean is clean. True and False. While IPC TM650 does state “how clean is clean,” we cannot recommend that anyone actually embrace that value. IPC allows for the use of a resistivity of solvent extract (R.O.S.E) test to determine the cleanliness of an assembly. These testers have been in production for more than 30 years. In fact, the cleanliness standard of >10µG NaCl/in.2 was developed in the 1970s.


APT-9611CER


Convertible Single / Dual Sided Probing


Today’s assemblies contain ad - 2012 IPC APEX EXPO


Visit us at the to see how a


Takaya Flying Probe Test system can help you! San Diego Convention Center February 28 - March 1, 2012 Booth 3403


TEXMAC, Inc. TEXMAC, Inc.


3001 Stafford Drive, Charlotte, NC 28208 704-394-0314


www.texmac.com www.texmac.com


3001 Stafford Drive Charlotte, NC. 28208 704-394-0314


vanced geographies not imaginable in the 1970s. There are some that sug- gest that we abandon the use of R.O.S.E. testers. That would be like throwing the baby out with the bath water. Instead, one should calculate the cost of failure. If an assembly fails, will that lead to property damage, loss of life, loss of reputation? If so, one should consider selecting a lower pass/fail value. In short, the more crit- ical the reliability, the closer to 0.0 one should strive to achieve. Aqueous Technologies Corpora -


tion is North America’s largest manu- facturer of fully automated defluxing and cleanliness testing equipment. The company manufactures deflux- ing, stencil cleaning and cleanliness testing equipment and has built more than 3,900 machines that are current- ly in use on six continents. Contact: Aqueous Technologies


Corp., 9055 Rancho Park Ct., Rancho Cucamonga, CA 91730 % 909-944-7771 fax: 909-944-7775 E-mail: konrad@aqueoustech.com Web: www.aqueoustech.com r


July, 2012


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