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www.us-tech.com
The Parallel Evolution of PCBs and Cleaning Methods
Continued from page 53
ed. This leaves microscopic crystals behind. These salt crystals may appear as white residue on the PCB, which can be difficult to remove. If these salts are not removed,
they can corrode solder joints and cause the entire board to fail. Making matters worse is the tendency of tightly packed boards to run hot, resulting in even more damage. Stubborn white residues usual-
ly require an aggressive flux remover or cleaning fluid. The fluid should also have certain physical properties,
such as low surface tension and short drying times. Low surface tension allows it to flow into tighter areas, while fast drying keeps it from stay- ing underneath components after cleaning. These cleaning fluids are better
than aqueous or water-based cleaners, which have higher surface tensions, evaporate slower and need rinsing to wash away surfactants and other additives in the wash water. Fiber optic components cannot
be cleaned with the same products used on the PCB itself. Cleaning
these components requires lint-free wipes and cleaning sticks that will not leave glue residue or lint on the fiber connectors. For the best results, an ultra-pure water-free cleaning fluid should be used. When cleaning 3D-printed
PCBs, material compatibility must be taken into account. These types of boards are typically made of two or more different materials, including plastics and metals. In general, the stronger the cleaning fluid, the high- er the risk that it may damage the PCB, especially plastics.
Vacuum Tweezer™ Solutions
For over thirty years we have been a leading supplier of vacuum handling solutions to the world’s high technology
fi rms. Our patented ESD safe products are used by clean room personnel, electronic assemblers, semiconductor manufacturers, the optics
industry and universities around the world. Virtual Industries success has come from
developing innovative vacuum tweezer tools to eliminate part damage and increase productivity in pick and place operations throughout high tech industries.. These tools provide customer specifi c solutions that make assembly and processing operations more productive and ergonomic. Parts range in size from 0.004” (0.1mm) up to 12.0” (300mm) for easy handling.
• Self-contained vacuum tweezers
• Portable, battery-operated continuous vacuum handling systems
• Bench top 110/220 volt vacuum tweezer systems
• Complete kits available
Visit our website or contact us for additional information.
Verification and Testing The best way to ensure proper
cleaning is to run a cleaning trial on sacrificial or test boards. The trial should start with a mild cleaner and continue on with stronger ones until the optimal results are found. Tests should also be run on multiple areas of the PCB. Some PCB designers conduct
their own trials in house. But, in some cases it is better to send the test boards to a cleaning fluid manu- facturer for a laboratory cleaning assessment. This way, the manufac- turer can ensure the owner of the board that it is being cleaned correct- ly with the fewest risks to the device’s health. This is also a good way to learn about cleaning process- es, regulatory compliance and improved worker safety. There is a vast array of PCB
cleaners on the market today. Each fluid or flux remover must have the right physical properties to clean well. But, it should also be formulat- ed to help protect air quality and ensure worker safety. A cleaning expert, such as
MicroCare, can recommend the best cleaning fluids and process improve- ments to achieve optimal PCBA cleaning results. Contact: MicroCare, LLC, 595
John Downey Drive, New Britain, CT 06051 % 1-860-827-0626 E-mail:
info@microcare.com Web:
www.microcare.com r
Antistatic Flooring’s Role in
Protecting
Against ESD Continued from page 52
guaranteed electrical properties and can be installed with no downtime. OhmStyle ESD™ carpet tile is
designed to be more decorative and is comfortable to work and walk on. The carpet acts like a sponge, quick- ly absorbing static electricity from the source and into the flooring material. EpoxyStyle ESD is a tough,
two-part epoxy acrylate floor finish for industrial environments that require ESD protection. This product is designed for industrial areas, such as shipping and receiving, warehous- es, high-traffic aisles, and production floors. The epoxy is water-based and available in four matte-finish colors. ESD protection is essential in
30 MORE THAN
2130 Victor Place, Colorado Springs, Colorado 80915 USA Website:
virtual-ii.com E-mail:
info@virtual-ii.com USA Telephone: 719-572-5566 Fax: 719-572-5504
environments where an electrical discharge can damage or ruin elec- tronic devices. ESD flooring helps to prevent the generation of static. Installing ESD flooring can help to reduce the overall risk of a damaging ESD event, ultimately creating a safer workplace. Contact: SelecTech, Inc., 33
Wales Avenue, Avon, MA 02322 % 508-583-3200 E-mail:
jberk@selectech.com Web:
www.selectech.com r
September, 2020
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