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Cleaning
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The Effects of Solder Mask Selection Cleanliness
Contamination Studies Laboratories Some case studies illustrating how solder mask affects cleanliness and reliability of the end product. 
The Layman’s Guide to Qualifying A Process to J-STD-001B Contamination Studies Laboratories What you should no to qualify a process so that it meets the J-STD-001B specification
The Layman’s Guide to Qualifying New Fluxes For MIL-STD-2000A or MT-0002 Contamination Studies Laboratories The purpose of this general paper, is to get back to that original easily understood test document and give you some practical guidance and technical pointers on how to go about demonstrating that your new process is capable of producing reliable hardware.
Why Clean? A saga of 'no-clean' fluxes Protonique Article that tries to answer the question ''Can 'no-clean' fluxes offer reliability in electronics?''. Read it yourself to get an answer.
Residues In Printed Wiring Boards and Assemblies Contamination Studies Laboratories This paper is an examination of residues on printed wiring boards and printed wiring assemblies. Sources of residues are illustrated and the effects of various residues are discussed. Case studies (5) are presented for bare board cleanliness issues, water soluble flux and aqueous cleaning processes, and low solids flux (no-clean) processes, with and without cleaning.
Qualifying a New Manufacturing Process Contamination Studies Laboratories Introduction to qualifying manufacturing process, focussed on process residues and the harm they may do to your products.
QUALIFYING A PROCESS TO J-STD-001B Contamination Studies Laboratories This paper addresses some of the fundamentals that have to be considered when qualifying a candidate process to the B revision of J-STD-001.
The Consequences of Ignoring Residues Contamination Studies Laboratories Three case studies of what happened when a manufacturer was ignorant of the residue.
Qualification Of No-Clean Materials And Processes For Cleaning Of Printed Circuit Board Assemblies EPA (Environmental Protection Agency) Extensive report (59 pages) about selecting and qualifying no-clean processes, with several case studies.
A New Process for Cleaning Flip Chip Devices:Reliability and Process Control Austin American Technology Description of a cleaning process that can be incorporated for Flip Chip cleaning applications with a high degree of reliability and safety. The process control capabilities and the closed-loop nature of the process provide clear advantages over other alternative methods
The Nature of White Residue on Printed Circuit Assemblies Kester White residue remaining after cleaning circuit board assemblies can be caused by a variety of chemicals and reactions. Rosin and water-soluble fluxes, circuit board resins and epoxies, component materials and other contamination all contribute to this complex chemistry. This paper discusses many of the sources of the residues that seem to be an ever-increasing occurrence
ULTRASONIC CLEANING PRIMER THEORY OF ULTRASONICS Chip Scale Review Magazine Description of the theory behind cleaning with ultrasonics.
CleanTech Online magazine about cleaning
Test Method for Cleanliness of PCB Assemblies by Electrolytic Reaction Bob Willis Homepage Small textfile describing an easy but sensitive testmethod to asses ionic cleanlines of printed circuit boards (assemblies)
Residue Analysis and Printed Wiring Boards / Assemblies Contamination Studies Laboratories The electronics manufacturer of today has a great deal more freedom to determine what tests best characterize the manufacturing process or manufactured product, and what tests provide the best differential between good and bad. However, with that freedom comes the responsibility of background research and investigation, and thoroughly understanding every step of the manufacturing process. The days of the “one size fits all” test method, test protocol, or pass / fail limit, are gone.
No-Clean Soldering to Eliminate CFC-113 and Methyl Chloroform Cleaning of Printed Circuit Board Assemblies EPA (Environmental Protection Agency) This manual, dated 1993, describes some consideration for changing the cleaning process or introducing no-clean. As the title suggest this was written as a guideline to getting rid of CFC-113.
Contamination Studies Laboratories Contamination Studies Laboratories CSL's Technical Libraries about contamination and cleaning
Preventing Contamination with Process Optimization SMT Magazine This article gives insight into the tests and process optimization that can prevent that reliability of PCB's is destroyed by contamination. (added on 23-Aug-2003)
Closing The Loop on Solvent Cleaning Systems Austin American Technology Report from Austin American Technology Corporation, discussing the development of a closed-loop cleaning system made possible by a combination of separation techniques, electrochemical detection, and the special formulation of a CFC alternative nonhalogenated organic solvent. Commercially oriented, but still good technical information.
Step 8: Cleaning SMT Magazine Many factors drive the decision to clean electronics assemblies. For those that function in harsh or uncontrolled environments, cleaning residue is a common standard. This article discusses the issues driving electronics assembly as they relate to cleaning. (added on 28-Sep-2003)
True Costs of In-Line Cleaning Electronic Packaging & Production Discussion about calculating the real costs of cleaning (added on 27-Apr-2003)
Case Study 37 Residues vs. SIR Contamination Studies Laboratories In considering whether an assembly is considered as "acceptable", there are two basic schools of thought.
Protonique Protonique Home page of the UNEP Solvents Technical Options Committee The Solvents, Coatings and Adhesives Technical Options Committee (STOC) of the United Nations Environment Programme (UNEP) is advisory to the Parties to the Montreal Protocol, through the Technical and Economics Assessment Panel (TEAP), in all matters relating to the reduction of stratospheric ozone depletion caused by the use of solvents From here several reports and papers are available for download, of which ''The 1998 UNEP STOC ASSESSMENT REPORT'' (with a chapter about Electronics Cleaning) is the most interesting.
Component Compatibility for Cleaning Circuits Assembly Bob Willis describes some tests that can be done to verify compatibility of components with cleaning processes. (added on 22-Aug-2003)
Case Study #2 - Leakage Leakage Everywhere Contamination Studies Laboratories In this case study, the effects of surface and absorbed fabrication residues on an assembler's operation were examined.
Case Study 21 Sure Hope We Dont Get Caught Contamination Studies Laboratories Different kinds of manufacturing processes, some are done exceptionally well, and some are done exceptionally bad.
Garbage in = Garbage Out, Effects of Elevated Bromide on the Qualification Process Contamination Studies Laboratories In this case study, the effects of elevated bromide from the fabrication process on an assemblers qualification process were examined.
Case Study #22 What A Difference A Little Soap Makes Contamination Studies Laboratories Anyone who has small children can tell you that if you want to get the kids clean after a day of playing, water alone will not do it.
Case Study #11 - I Could Solder to Concrete Contamination Studies Laboratories In this study, we see what can happen when you use an active flux totally outside of the manufacturers recommendations.
Case Study #14 - Pop, Sizzle and Fry Contamination Studies Laboratories In this study, the cause of laminate blistering in aqueous cleaned assemblies was examined.
No More Than I HAVE To, Case Study 26 Contamination Studies Laboratories Anyone with a teenager is occasionally amazed at the effort put forth to avoid work.
Case Study 24 Bare Board Roulette Contamination Studies Laboratories This is the second of a two-part study. In part 1 (March 98), assemblies experienced high levels of corrosion, electrical leakage and metal migration.
Case Study 27 It Always Works for the Repairman Contamination Studies Laboratories One of Murphy's Laws says that any broken appliance will always work when demonstrated for the repairman.
Case Study #6 - Remedial Cleaning of the Mask From Hell Contamination Studies Laboratories This is a follow up study to the Mask from Hell. It involves trying to clean residues entrapped in a very porous, degraded solder mask.
Case Study #17 - Just Call Me Fireproof Contamination Studies Laboratories In this study, the effects of high levels of bromide residues on circuit boards was examines, and how much bromide is a hazard.
Case Study #10 - But Im Wearing Finger Cots! Contamination Studies Laboratories Every once in a while, it is good to examine assumptions you (or your management) have made in your manufacturing process. This case study involved handling residues.
What, Me Worry About Fumes? Switches mysteriously lose contact. Contamination Studies Laboratories Low solids fluxes are finding increasing usage around the world. The cost savings afforded by the elimination of the cleaning operation is often attractive, but the world of no-clean fluxes has many dangers to the uninformed.
Case Study #5 - The Mask From Hell Contamination Studies Laboratories A manufacturer of a low-end commercial product was experiencing a wide spread failure during burn in testing. The failure mechanism was excessive leakage currents and an almost instantaneous metal migration situation.
Case Study #12 - Peelable Mask, Unpeelable Residues Contamination Studies Laboratories In this study, the effects of temporary processing materials are studied, in this case a peelable latex temporary solder mask.
Case Study #20 Just Crank Up the Pressure Contamination Studies Laboratories In this study, we look at a study in cleaning that focuses on two misconceptions: (1) that you get better cleaning by increasing the spray pressures; and (2) that global board extractions will always tell you if you have a contamination problem.
Case 30 Microcanyons Contamination Studies Laboratories Nearly all electronics assemblers make some sort of surface mount or mixed technology assembly.
Case Study #13 That Darn Casting Contamination Studies Laboratories In this study, the outside factors were examined which were causing circuit failures during power temperature cycling (burn-in acceptance test).
Case 33 A Problem with Teflon Insulation Contamination Studies Laboratories Most of us consider polytetrafluoroethylene (PTFE or Teflon) as a fairly inert or benign material.
Case Study 1 - The Crystalline Entity Contamination Studies Laboratories In this case study, detrimental residues present in a water-soluble flux assembly process were examined.
Case Study #8 - Talk About Being Canned... Contamination Studies Laboratories In this study, an assembler was helped tracking down the cause of extensive corrosion on a printed wiring assembly.
Case Study #15 - Doing Everything Right and Still Fail Qual Testing? Contamination Studies Laboratories In this study, the assembler was examining different combinations of conformal coatings and OA fluxes, using qualification guidelines of MIL-STD-2000A, Appendix A.
Case Study #19 - Im Surprised You Have Any Leads Left! Contamination Studies Laboratories This is a case study involving component manufacturing and the residues involved.
Case Study #7 - When A Cool Flux Should Be A Hot Item Contamination Studies Laboratories In this study, work was done with an assembler who was attempting to qualify a hand soldering process to J-STD-001 A, Appendix D and F guidelines.
Case Study #25 Were All Fed Up Contamination Studies Laboratories Every once in a while, when doing failure analysis, it becomes necessary to try to recreate a failure mechanism in order to determine the base problem.
Case 34 Sulfates in Vias II Contamination Studies Laboratories In a previous column, a problem that an assembler was having with high levels of sulfate remaining in small diameter (less than 3 mils) vias was examined. In this case study, the examination is continued.
Case Study 23 On the Average, Im OK. Contamination Studies Laboratories In this case study, a problem concerning corrosion, metal migration, and electrical leakage is looked at, potentially affecting over 100,000 assemblies (field and inventory) with more produced every day.
Account of a Cleaning Systems Changeover SMT Magazine A self-contained aqueous cleaning and drying unit, supplemented with a wastewater recycling system, replaces an isopropyl alcohol vapor-degreasing system with Positive results. (added on 08-Nov-2003)
Cleaning Electronic Production Electronics Production Magazine does not exist anymore, but their extremely usefull online-encyclopedia is still available from SMTinfo.net. This part gives an introduction to cleaning of PCB's.
Cleaning Underneath 4 Mil Standoffs SMT Magazine The increase in component complexity results in a continuous decrease in standoff spacing between the components and the substrate's surface (currently 2 to 4 mil). This article looks at mechanical agitation cleaning systems for best cleaning results. (added on 25-Jan-2004)
White Residues on Soldered Printed Circuit Assemblies National Physical Laboratory A summary of NPL's accumulated experience with regards to the nature and origin of white residues remaining after cleaning soldered circuit board assemblies. (added on 04-May-2004)
Lead-Free Soldering: DOE Study to understand its affect on Electronic Assembly Defluxing Leadfreemagazine.com The purpose of the study described in this paper was to evaluate how the use of nitrogen versus non-nitrogen reflow atmospheres affect the cleanability of flux residue from RMA, synthetic and water-soluble surface mount solder paste residues. (added on 13-Jun-2004)
Assembly and Cleaning of CSPs for High, Low, and UltraLow Volume Applications. Nasa This paper presents lessons learned on assemblies with CSP's at three facilities with high, low, and ultralow volume production of. (added on 05-Aug-2004)
White Residue - Good or Bad - Part 1 Foresite This case looks at how different water qualities and cleaning chemistries affect the appearance of white residues and the cleaning effectiveness of BGAs. (added on 20-Dec-2005)
Mean Green Corrosion Foresite Selective soldering on ImAg boards built with a no clean process can be a very touchy situation. (added on 22-Jan-2006)
Can you Clean a No Clean? Foresite This article looks at a specific case involving NTF returns with a customer using a no-clean process, and looks at developing a successful cleaning protocol for cleaning assemblies constructed with a no-clean process. (added on 22-Jan-2006)
Does Conformal Coating Stop Electrical Leakage Problems? Foresite This analysis shows that conformal coating is only effective if there are no ionic residues entrapped underneath - though conformal coating may slow the absorption of moisture, it does not over time prevent moisture absorption and reaction with ionic contamination. (added on 22-Jan-2006)
Why Test for Ionics Anymore? SMT Magazine Short background on ionic contamination testing. (added on 11-Sep-2004)
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© 2004 Daan Terstegge - All rights reserved. |