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July, 2019

Page 63

SN100C Achieves 20 Years ofReliable ServiceT

By Keith Howell, Technical Director, Nihon Superior USA

he implementation of the European Union’s RoHS directive mandated can accommodate the long-term and impact strains to which a solder joint can
the use of lead-free solders in the electronics industry by 2006. However, be subjected. The eutectic character of SN100C alloy and the associated highfluidity provides faster wetting and increased
five years before, Japan’s appliance recyspreadability over SAC305, which is beneficial
cling waste electronic and electrical equipmentin wave and hand soldering applications, as well(WEEE) regulation went into effect. This regulaas in reflow.
tion covered home electrical goods, air conditionDue to the significant increase in ecoers, refrigerators, freezers, TVs, washingfriendly hybrid and electric vehicles, the demandmachines, and clothes dryers.
for solder joints to resist thermal fatigue is also
A new category of waste type, a category thatgrowing. Vehicles are often exposed to extreme
includes precious metals, as well as such toxic subtemperatures during service and the solder must
stances as lead (Pb) and polybrominated biphenyls
function in a range of environments.
(PBBs) was included in the WEEE regulation. For
the solution to replace tin-lead solder, the industry
Continued on page 69
SnCu (left) and SN100C (right).
looked to lead-free alloys, including
tin-copper (SnCu).
But, the SnCu did not perform
as expected as a eutectic solder. The
industry was forced to research
improvements to turn SnCu into auser-friendly solder.
The Birth of SN100C

In 1998, Tetsuro Nishimura, thenNihon Superior’s technical manager,
now CEO, in partnership with theaudio and video division of Panasonic
Corporation extensively investigatedthe causes of the poor performance ofSnCu. Nishimura identified nucleationof the second phase of the eutectic
Cu6Sn5 as the problem.
Adding a trace amount of nickel,
0.05 percent, was discovered as themost effective method of enhancing theperformance of the solder. Duringsolidification, nickel works by facilitating the nucleation of the intermetallic
Cu6Sn5, making it possible to solidify
as a eutectic, such as tin-lead solder.
With the microalloying of nickel
to SnCu, SN100C was born. During
the development, a germanium (Ge)addition was identified as the mosteffective way to control the oxidationthat generates dross.
Nishimura was awarded “BestInventor” by SMT Today magazineduring the 2015 SMTA International
conference and exhibition in recognition throughout the electronics
industry as the inventor of SN100C
and the pioneer of microalloyed solders.
This award recognizes an individual or team whose innovations
have not only addressed a need andsolved a problem, but also have beenused to drive improved efficiency, productivity and performance within theelectronics manufacturing industry.
“The small amount of nickel islike the effect of salt in a dish. Asmall amount has no taste, no effect,
but a large amount overpowers thedish, ruining the taste. A good dishrequires the right amount of salt, justas SN100C has the right amount ofnickel. On the other hand, germanium is like pepper, which gives a goodtaste, but the amount may be varied,”says Nishimura.
Commercial Debut
The first commercial use in mass
production for the newly developed
SN100C solder was in 1999 for a
Panasonic VCR. Since then, SN100C
has been widely accepted and has
gained a reputation as a reliable solder.
The reliability of SN100C has
been proven in a wide range of electronics assembly products, fromappliances to industrial, automotiveand aerospace. The alloy delivers asilver-free stable microstructure that

July, 2019www.us - tech.com

Page 67

Model-Based Engineering for Wire Harness Manufacturing
Continued from previous pageknowledge. Tribal knowledge is information aboutprocesses, methodologies and more that is stored
only in certain employees’ memories. This information is unwritten, but is often critical to successfully implementing a process, creating a product ormaintaining quality levels.
Employees that change roles or leave thecompany will take this information with them,undermining the process or product they once
oversaw. This presents a real risk for many companies, harness manufacturers included. Ten thousand Baby Boomers retire every day in the U.S.
In Canada, from 2011 to 2016, there was a 20
percent increase in the number of Canadians thatreached the age of retirement. In the U.K., it is predicted that between 2016 and 2020 the number ofpeople between 16 and 49 will decrease by 700,000.
The workforce is shrinking. How can managers
maintain productivity with a younger, less-experienced and smaller workforce? In particular, how can they capture the vital
information and expertise held by
their current employees to prevent a
catastrophic loss of tribal knowledge?
In a typical, high-level, wire
industry, manufacturing engineering
flow, design engineering first releases
initial designs or engineering changes
for costing and to provide quotes to thecustomer. Next, the main formboard isdesigned, followed by production modules and subassemblies, which occasionally require their own assemblyboard. Then, the engineers will design
a bill of process (BOP) for the entire
harness, allocating wires, splices,
twisted wires, and all remaining material to its designated equipment orworkstation.
The BOP is then released into
the enterprise resource planning(ERP) system. This is followed by balancing and optimization of the final
assembly carousel and then creationof the work instructions.
Introducing Error
Errors from data reentry canoccur at any of these stages, each ofwhich requires great skill and experience. Adjustments and corrections
made downstream in the flow must
be fed upstream manually in order toachieve data coherency.
The conventional wire harness
manufacturing methodology is vulnerable to errors from fragmented
processes and the loss of tribal knowledge as engineers retire or leave theirjobs. Other key issues include inconsistent or inaccurate costings, suboptimal
formboard design or manufacturing
process design, as well as misplacing
key information on the shop floor.
These can lead directly to inefficiency
during production. As a result, manufacturing and overall costs can overshoot the quote made to the customerand production quality can suffer.
Model-Based Engineering
A model-based flow unifies thepreviously fragmented domains ofdesign and manufacturing byautomating data exchange and providing engineers with access to crossdomain decisions. Tribal knowledge,
previously held by experienced engineers, is captured through integrated
design rules that support automation, guide all engineers consistently
and check designs for issues.
There are three key aspects todigitalization and the model-based
enterprise in the wire harness industry. First are digital models of thewire harness product and the manufacturing process. The digital modelsof the harness and production process
together create what is known as a“digital twin.”
Automation is the second key aspect. Today’s
harness design and manufacturing solutions canconsume design rules created by veteran engineers
and use them to automate the transformation of
the digital harness and process models into BOPs,

The three key tenets of a model-based
enterprise: digitalization, automation anddata reuse.

work instructions and other output formats. This
simultaneously embeds tribal knowledge into thecompany’s production flow, safeguarding it from
employee turnover.
The third aspect is data reuse. Instead ofrecreating or reengineering data, in a model-basedengineering flow, data is created once and reusedto the greatest extent possible by all upstream anddownstream consumers.
In a digital world, companies create a digital
thread in which all of the functions, from architectural and functional design through to physicaldesign, manufacturing engineering and after-sales
service, can all use the same data. At each stage ofthe harness lifecycle, each stakeholder can use thesame data models and have access to decisions
that are made in other domains. Using a digital
thread, design cycles are faster and issues can becaught and resolved earlier in the process when
Continued on page 69

www.us - tech.com

July, 2019

Page 69

SN100C Achieves 20 Years of Reliable Service

Continued from page 63
In a thermal cycling test, it was shown that
there are significant differences in the reliability ofSN100C versus that of the Sn-3.8Ag-0.7Cu alloy.
After 2,000 cycles, cracks started to appear. At
4,000 cycles the alloy failed completely. In the solder joints made with SN100C, there was no significant cracking until 4,000 cycles.

Another product the company has developed isthe Alconano silver sintering paste, which is basedon a patented technology that makes it possible toNihon Superior’s Heritage
Nihon Superior has been a leader in solderingand brazing since it was founded in 1966 byToshiro Nishimura and continues its tradition ofdeveloping lead-free joining materials withimprovements in reliability, thermally stable joining and lead-free die attach. Toshiro’s son,Tetsuro, now runs the company and Toshiro’sgrandson, Takatoshi, is also involved in the company, making Nihon Superior a third-generation
family-owned business.
The company continues todevelop highly reliable products andis committed to earning its customers’ highest level of trust by taking full responsibility for every product delivered. The company remains
ready to meet rising demands fordiversification, increasingly sophisticated technologies and environmental protection.

Three generations of the Nishimurafamily (from left): Takatoshi, founderToshiro, and CEO Tetsuro.

effectively join most metals, as well as silicon and silicon carbide at low sintering temperatures, in nitrogen if necessary, without the nitrous or sulfurous
residues that are the byproducts of the sintering ofsome other nanosilver pastes. The highly active surface of the nanosilver particles and the consequent
strong capillary forces make it possible to achievestrong bonds with high electrical and thermal conductivity at low temperatures, without the needfor external pressure.
Twenty years ago, when SN100C was invented,
it was considered to be a reliable and stable alternative to SnPb solders. Now, its reputation has growneven stronger and has evolved to meet new industry
challenges.
Contact: Nihon Superior USA, LLC, 1395
Hawk Island Drive, Osage Beach, MO 65065
E-mail: k.howell@nihonsuperior.co.jp
Web: www.nihonsuperior.com r™

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Beyond SN100C

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It is becoming increasingly apparent that the simple ternary
SAC305 alloy cannot deliver everything that the electronics industry
requires from a solder, in terms of
cost and performance. The cost of thethree to four percent silver required
to get the 422.6°F (217°C) solidus
temperature was one of the main reasons for choosing SnAgCu eutectic
that had reduced silver content as
low as 0.1 percent, or even without
silver altogether.
Nihon Superior has now developed its SN100CV alloy that gains its
strength from solute atoms in the tin
matrix of the joint unlike silver-containing alloys that derive theirstrength from a dispersion of fineparticles of eutectic Ag3Sn. The addition of bismuth enables thermallystable solder joints, even after thermal cycling.

Model-BasedEngineering...
Continued from page 67
they are much less expensive. By
also reducing design rework, datareuse minimizes costs and enables
superior manufacturing efficiency.
In order to survive and grow inthis challenging environment, harness
manufacturers must significantly
change their methods. Digitalization
is a key adaptation for harness makers, offering the tools needed to survive in an extremely dynamic industry. A digital model-based flow unifies
the previously fragmented domains ofdesign and manufacturing and captures tribal knowledge held by experienced engineers through integrated
design rules. To meet the demands ofan evolving industry, it is time for wire
harness makers to become digitalenterprises.
Contact: Mentor, a Siemens
Business, 8005 S.W. Boeckman
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E-mail: larry_toda@mentor.com
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See at SEMICON West,
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See at SEMICON West, Booth 1534