Expert Details

Expert in Electrical Connectors

Expert ID: 108424 Canada

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Expert has applied his physics background to generate a fundamental understanding of temperature generation and material transport in electrical contact spots (a-spots) in bulk electrical interfaces. Over 25 years, his research showed that 1) Sintering effects occur in a-spots even at room temperature, if a-spots are smaller than about 100nm. These effects contribute to self-healing of electrical contacts. 2) The growth of a-spots at elevated temperatures is driven by material interdiffusion across the a-spots. 3) The conventional voltage-temperature relation of contact physics breaks down whenever the a-spot diameter is of the same order of dimension or smaller than the electronic mean free path in the conductor. 4) a-spots in electrical interfaces of certain metals melt at a potential difference across the contact that is much lower than the conventional "melting" voltage. This effect has shown that a-spot temperature is sensitive to the temperature-dependence of the electrical resistivity and the thermal conductivity of the contacting bodies. It also explained the origin of early failure of selected electrical contacts where the mating surfaces consisted of plated nickel. 5) Intermetallic compounds at bimetallic interfaces grows within a-spots and affect deleteriously the resistance of the contact spots. The formation of these compounds is thus highly deleterious to the performance and life of an electrical interface. 6) The effect of contact wipe is effective in minimizing the effect of contaminant surface films on contact resistance, even in the case of aluminum surfaces where native surface oxide layers are formed almost instantaneously in air.

His research, along with other contact resistance information produced over 25 years, has allowed him to establish guidelines for the use of materials and platings/coatings in power connectors. He has shown that aluminum electrical contacts are reliable if the connections are prepared according to certain specifications. He also testified successfully at the Ontario Royal Commission on the use of aluminum wiring in favor of the continued use of aluminum electrical conductor in houses and at industrial sites. He also pointed to the limitations of conventional contact-resistance engineering for small connection devices (e.g., at the microchip level).

His work in the electrical contact arena led to numerous scientific/technical publications, including Chapter I in the recent book "Electrical Contacts, Principles and Applications" (Marcel Dekker, Inc., 1999), and to several international awards. The most recent such award is the Ragnar Holm Achievement Award presented in 1998 by the IEEE. He has consulted for clients in the power, automotive, and electronics industries in relation to contact materials, use of electroplates, connector design, and connector manufacture. He has also lectured extensively and internationally at seminars, workshops, and intensive courses on electrical contacts.


He has considerable experience in connector design relating to the power and industrial-electrical industries. He also has experience in connector design for the automotive industry. The connector types he has worked with include bolted, compression, crimp, wedge-type, insulation-piercing, insulation-displacement, sliding, coaxial, high-power switch, and other connector types. His design experience stems from many years of connector-evaluation work done at Alcan International Ltd. and connector design/testing done at AMP Inc. His approach to connector design emphasizes concept simplicity and an engineering design that can lead to reliable performance and to manufacturing cost-effectiveness. The use of computer-based design reduces the design cycle from months to weeks. Connectors are designed to meet specifications set by national and international Standards organizations such as CSA, ANSI, NEMA, IEEE, IEC etc. He has been closely associated with many of these organizations for many years. He is also thoroughly acquainted with the wide range of connector testing procedures. He has written extensively on the operating cost-effectiveness of well-designed, high-performance connectors.

He has extensive experience in wire and sheet-metal bonding. He has consulted on wire bonding produced by ultrasonic techniques, in particular the effect of substrate roughness, substrate material, and surface contamination on the ultrasonic bondability of aluminum and gold electronic wire. His experience in sheet-metal bonding relates primarily to roll-bonding techniques, particularly in copper-alloy/copper-alloy, aluminum/aluminum and copper-alloy/aluminum sheet bonding. Optimal adhesion in roll-bonded composites is sensitive to the total metal deformation. Roll-bonding processes are used primarily in metal cladding for high-power connectors and in the production of selected types of heat exchangers.


He has extensive experience in the tribology (friction/lubrication/wear) of mechanical and electrical interfaces relating to copper and aluminum alloys. His research has shown that lubricants are effective only when they react chemically with at least one of the sliding surfaces. He also showed that lubricants that react chemically with an oxidized surface such as tin, indium, aluminum, etc. may be detrimental to electrical contact properties with these metals. This stems from the reactivity of the lubricant with the metal substrate exposed to the lubricant through fractures in the surface oxide layers. He has worked with lubricant suppliers to eliminate additives that may be deleterious to electrical contact performance.


He has considerable expertise in failure analysis of electrical connectors and electric conductors that failed, both in laboratory tests and in service use. He consulted extensively on the causes of electrical failure (burnout) in connectors from the power utility, industrial-applications, and automotive industries. Some consultations have involved the use of failure mode and effect analysis (FMEA) to increase product reliability. He has carried out extensive investigations of the effects of corrosion, in particular the effects of salt spray and exposure to harsh marine environments, on connector performance. He has also written and made several presentations on these topics both to end-user audiences and at international conferences (see Selected Publications). He has also served as expert witness in litigation cases in which a major injury was attributed to the failure of a connector.

He has expertise in the metallurgy and metalworking of aluminum alloys, having spent many years in the aluminum industry before joining the electrical connector industry. His expertise covers heat treatment, rolling, extrusion, and twin-belt and twin-roll casting of aluminum. Jointly with colleagues, he developed a patented roll-casting technique in which the gaseous atmosphere around the rolls was modified to control surface finish and thermal heat transfer at the contact interfaces with the rolls. He also has experience in semi-solid forging to forge-cast aluminum components with small dimensional-tolerance requirements, which is often demanded for aluminum packaging in military microwave applications. He has also expertise in the corrosion resistance of aluminum alloys such as brazing alloys and electrical connector alloys. He has consulted extensively on the use of aluminum alloys for connector and microwave circuit applications.

He has expertise in the use of electroplated, vacuum-deposited, sputtered, and metallurgical coatings for protection against corrosion and/or mechanical wear. In the late 1970s, he was one of the first investigators to evaluate the use of TiN/TiC coatings on extrusion dies for aluminum to extend die life. He also designed and supervised the construction of a nanoindenter device to quantify the microhardness of thin coatings (thinner than 1 micron). He is fully familiar with microhardness and nanohardness measurement technologies and literature. He is one of the first investigators to use a nanoindenter device to characterize the hardness of novel multilayer coatings for electrical connectors. He has also consulted widely on the use of vacuum-sputtered and CVD (chemical vapor deposition) films as wear-resistant coatings on devices ranging from aluminum-based magnetic information-storage disks to prosthetic devices.

He has expertise in the characterization of surface roughness using a wide range of stylus-type and optical profilometers. He consulted with a major manufacturer of optical profilometers to identify the main surface roughness parameters characterizing the surface of hard magnetic information-storage disks. He has used surface profilometry extensively during his career to characterize surface roughness of a wide variety of products and devices such as metal strip, metal-forming rolls, semiconductors, electrical connectors etc. Optimal connector performance often stems from a tailored surface roughness. He is also familiar with atomic force microscopy (AFM) to characterize the surface of relatively smooth metal and semiconductor surfaces. He was a member of the ASME B.46 committee from 1987 to 1996, which was responsible for writing standards for surface roughness measurements and characterization using a wide variety of techniques, including AFM. He contributed to the standards that were issued by ASME in 1995.

He has considerable experience in the use of surface characterization techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), ESCA and Auger electron spectroscopies, SIMS, single-reflection infrared spectroscopy, Rutherford backscattered scattering (RBS), high-energy ion recoil spectroscopy, etc. He introduced the use of radioactive Ni63 as a source of energetic electrons to carry out EDX analyses of surfaces in vacuum. He was also the first investigator to determine the atomic structure of the interface between aluminum and its surface oxide using high-resolution TEM. He has used and consulted on the use of ESCA and Auger spectroscopies for the chemical characterization of surfaces of films, coatings, and other materials in a wide range of devices, including electrical connectors. These surface characterization techniques are often essential to identifying the causes of lubricant breakdown, the causes and rates of corrosion ingress into surfaces and interfaces, and the chemical composition of foreign layers detrimental to connector performance.

He invented a novel process for the brazing of aluminum in a nitrogen atmosphere. He is recipient of several patents on the process. In 1995, he was recipient of a major award from the American Welding Society for the invention. This new technology does not rely on the use of a "brazing alloy," which is relatively expensive, but instead generates brazing alloy in-situ in a joint by the reaction of a mix of silicon powder and oxide-dissolving flux at a temperature of about 600C. This process reduces significantly the cost of brazing aluminum components. He has consulted with several manufacturers of aluminum brazing materials and automotive companies on the process.


He has considerable experience in the measurement of intermetallic growth rates and on means of mitigating intermetallics formation at electrical interfaces. His expertise covers copper-alloy/tin, copper-alloy/indium, copper-alloy/zinc, copper-alloy/nickel, aluminum/copper-alloy, copper-alloy/gold and many other bimetallic systems. He has consulted widely on the prevention of intermetallic formation with electrical connector and printed circuit board manufacturers.


An expert in friction welding and cold welding technologies, with exceptional experience in the copper-aluminum and aluminum-aluminum metal systems, he has consulted with connector manufacturers on ways of increasing the strength of the bond at the bimetallic interface and mitigating the formation of deleterious intermetallic compounds in friction-welded power connectors.


He identified the cause of a connector failure at the generating station of a major electrical-power utility company in Western Canada. He led an engineering team in a product development project at a well-known connector manufacturer, which resulted in reduced product development time significantly. He accelerated design/development of a nitrogen-atmosphere brazing furnace at a well-known furnace manufacturer's facility.

Education

Year Degree Subject Institution
Year: 1970 Degree: PhD Subject: Physics Institution: University of Toronto
Year: 1965 Degree: MSc Subject: Physics Institution: University of Toronto
Year: 1963 Degree: BASc Subject: Engineering Science Institution: University of Toronto

Work History

Years Employer Title Department Responsibilities
Years: 1999 to Present Employer: Undisclosed Title: Consultant Department: Responsibilities:
Years: 1998 to 1999 Employer: AMP Inc., Markham, Ontario, Canada Title: Chief Technbologist & AMP Consultant Department: Responsibilities:
Years: 1996 to 1997 Employer: AMP, Inc. Title: Director of Technology Department: Responsibilities:
Years: 1994 to 1995 Employer: AMP, Inc. Title: Director of Research Department: Responsibilities:
Years: 1987 to 1993 Employer: Alcan International Ltd., Kingston R&D Centre, Kingston, Ontario, Canada Title: Principal Scientist Department: Responsibilities:
Years: 1987 to 1993 Employer: Alcan International Ltd. Title: Senior Scientist Department: Responsibilities:
Years: 1974 to 1983 Employer: Alcan International Ltd. Title: Senior Investigator Department: Responsibilities:

International Experience

Years Country / Region Summary
Years: to Present Country / Region: Europe & Middle East Summary: He traveled with Marketing/Sales teams to promote sales of connector products. His contributions focused on promoting the knowledgebase and technological leadership of AMP Incorporated. He gave frequent technology seminars in England, Scotland, and France and also made presentations in Italy and Israel. These presentations had a major impact on retaining accounts and acquiring new ones. He made presentations to selected automobile manufacturers in Germany and led to a joint development program with AMP Incorporated.
Years: to Present Country / Region: Summary: Australia, Thailand, Vietnam, Malaysia, Singapore, China, Japan: he traveled with Marketing/Sales teams to promote sales of connector products. His contributions also focused on promoting the knowledgebase and technological leadership of AMP Incorporated. He gave technology seminars in the Asian countries listed above. In particular, he carried out speaking tours at customers' locations in Shanghai, Beijing, Xian, Wuhan in China in 1995 and 1997. In 1996, Expert organized and funded research at the Beijing University of Posts and Telecommunication and Hebei University to support efforts to design connectors compatible with the demands of the Chinese power-connector market. He was actively involved in the development of China-specific connectors and in establishing manufacturing facilities/sourcing for these products in China.
Years: to Present Country / Region: Brazil, Mexico Summary: He traveled extensively with AMP's Director of Business Development in Brazil to promote new business and the sale of connector products. He presented technology seminars in Sao Paulo, Curitiba, Belo Horizonte, Salvador, Rio de Janeiro, and other major commercial centers in Brazil in 1995, 1996, and 1997. He presented similar seminars in Mexico City and Acapulco in 1996. The impact on the acquisition of new accounts was significant. His visit to Brazil in 1996 was recorded in Brazil's technology review Revista Cotaao.

Career Accomplishments

Associations / Societies
He is a member of the American Physical Society, the Institute of Electrical and Electronics Engineers, the Society of Tribologists and Lubrication Engineers, the American Association for the Advancement of Science, the Materials Research Society, and the New York Academy of Science.
Awards / Recognition
He was awarded the IEEE Erle Shobert Award for Best Paper. He was also recipient of the IEEE Ragnar Holm Achievement Award and the Robert L. Peaslee Brazing Award from the American Welding Society. He was honored with the Best Paper Award by the IEEE Holm Conference on Electrical Contacts and the 1980 Best Transactions Paper Award by the Components Hybrids and Manufacturing Technology division of the IEEE.

Additional Experience

Expert Witness Experience
He testified successfully at the Ontario Royal Commission on the use of aluminum wiring in favor of the continued use of aluminum electrical conductor in houses and at industrial sites. He also served as an expert witness in litigation cases in which a major injury was attributed to the failure of a connector in Illinois.
Training / Seminars
He was an instructor for the IEEE Intensive Course on Electrical Contacts. This course has been given yearly for the past 30+ years. Expert was invited to instruct in contact fundamentals. He developed the curriculum for his part of the course.

He was a prime-mover and instructor for the Workshop on Reliability of Power Connections, sponsored by the Canadian Electricity Association. The first two of these workshops were held in Montreal (presentations in French) and Toronto respectively on 28 April and 11 June 1999. Two additional workshops are scheduled for Quebec City and San Francisco respectively on 23 October and 16 November 1999. Additional Workshops are being planned for 2000.

He developed customer-oriented seminars on connector technologies for audiences in Canada, US, France, UK, Brazil, Mexico, several countries in Asia (particularly China). About half of these seminars addressed the cost advantages of high-reliability electrical connectors and the technological reasons for these advantages.
Vendor Selection
He has experience locating vendors of electrical connectors,
aluminum, copper alloy and wire and cable.
Other Relevant Experience
In addition, he has played a role in the assessment of technology competencies of high-technology companies seeking venture capital. He has been working with mutual fund companies to assess the technology competencies of high-technology firms prior to stock acquisition by the funds.

Language Skills

Language Proficiency
French Expert is proficient with French,
Hebrew Expert is proficient with Hebrew.
Italian Expert knows some Italian.

Fields of Expertise

bonding wire, circuit interconnection tie, conductor jointing, contact resistance, crimping, electrical coupling, insulation displacement connector, profilometry, switch contact, electric contact, electrical conductivity, thermal conductivity, contact potential difference, electric contact contamination, electric switch, electrical burnout, electrical contact material, electrically conductive material, crimped connector, electrical connector, high-voltage connector, electric contactor, electrical socket, electric contact design, electrical connector design, gold bonding wire, contact metal, electrical contact finish, plated gold, copper physical property, electric contact tribology, electric conductor failure, electrical connector corrosion, electrical connector reliability, aluminum alloy, aluminum corrosion, aluminum corrosion resistance, metal strip, corrosion protection, electrodeposition, surface hardening, vacuum deposition, profilometer, surface characterization, inerting, aluminum brazing, printed circuit board soldering, soldering, cold welding, friction welding, heat-affected zone, stage gate process, subsea electrical connector, switch selection, junction box, limit switch, electrical leakage, electrical connector injection molding, military connector, leakage current, electrical connector manufacturing, bed-of-nails testing, electrical impedance, metal-semiconductor-metal photodetector, magnet wire termination, battery terminal, optical connector, electrically conductive elastomer, electrically conductive gasket, indium electric contact, printed circuit board connector, sterling silver, electrically conductive ceramic, patch electrical connection, dry contact, slip ring, electrically conductive coating, high-voltage engineering, corrosion-resistant alloy, metal alloy, electronic interconnect system, hard solder, electronic interconnector, interconnect substrate, electrically conductive film, electrically conductive polymer, electrically conductive adhesive, interconnection wiring, induction brazing, electroplating, electrically conductive epoxy, technology mapping, interconnector, electric conductor, material wear, wire, wiping contact, point contact, ohmic contact, electrical lead, electrical jack, interconnection technology, inert-gas brazing, gold alloy, copper alloy

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