April 12, 2016Effects of Ultrasonic Cleaning http://www.circuitnet.com/experts/52525.htmlDoes ultrasonic cleaning have an adverse effect on crystals or other components on a PCBA?If there is a negative affect are there any ultrasonic cleaning methodologies that would prevent problems?K.U. Experts CommentsThe answer is no. The answer is yes.Take your pick. There are two schools on this subject. Smart, intelligent, and experienced engineers will tell you that there is significant risk of component damage when exposed to ultrasonic energy. From damaged crystals to wire bond fractures, that fact is that there is the possibility of damage. In fact, several years ago, a major assembler of electronic assemblies published data linking component damage to ultrasonic energy.In reality, while the above statements are true, the chance of component damage on modern ultrasonic cleaning equipment is rare. Modern ultrasonic cleaning equipment utilizes frequencies of 40 kHz. The frequency is "swept" up and down to reduce potential component damage. Also, if the watts to fluid volume is low enough, damage will be further reduced.Here's the real issue. It doesn't really which school of thought you subscribe to. What matters is what your customer, QC manager, reliability engineer, and others think.The fact that there is legitimate belief that ultrasonic energy has the potential to cause component damage normally precludes it from being used to preform a defluxing process. The fact that you are asking this question, illustrates my point that ultrasonic energy is not openly accepted in the defluxing world, despite compelling arguments to the contrary.I would strongly recommend spray-in-air technology for your cleaning / defluxing requirements. It is universally accepted as the conventional wisdom for defluxing applications and is never suspected of contributing to component damage.Mike KonradPresidentAqueous TechnologiesMr. Konrad has been in the electronic assembly equipment industry since 1985. He is founder and CEO of Aqueous Technologies Corporation, a manufacturer of automatic de-fluxing equipment, chemicals, and cleanliness testing systems. We have several published articles available for download on ourweb site, click on the "Recommended Reading" button. The article by B.P. Richards et al. "Does Ultrasonic Cleaning of PCBs Cause Component Problems: An Appraisal" best addresses your question: "Does Ultrasonic cleaning have an adverse affect on crystals or other components on a PCBA?" My paper, "Reducing the Cost of Misprinted PCBs", addresses the parameters that would help prevent potential problems.I also recommend the IPC-7526, "Stencil and Misprinted Board Cleaning Handbook."Bill SchreiberPresidentSmart Sonic CorporationMr. Schreiber developed the original ultrasonic stencil cleaning process in 1989. Obtained the only EPA Verification for specific parameters of Environmental Safety, User Safety and Cleaning Efficiency for a stencil cleaning process. If the frequency of the crystal matches the frequency of the ultrasound, then there is resonance and the component can fail.Regular cleaners are better than ultrasonic cleaners precisely for this reason.Karthik VijayTechnical Manager - EuropeIndium Corp.Currently with Indium Corporation and responsible for technology programs and technical support for customers in Europe. Over 15 yrs experience in SMT, Power, Thermal & Semiconductor Applications. Masters Degree in Industrial Engg, State University of New York-Binghamton.In the early days of integrated circuits, say the 1960s and 1970s, ultrasonic cleaning was generally