Illustrator Hiroki Tsuboi visits Sumitomo Group
NSG Vietnam Glass Industries Ltd.

The Nippon Sheet Glass (NSG) Group is a manufacturer of glass and glazing products for architectural, automotive and other applications. With a network of plants spanning the globe, it sells its products in over 100 countries. NSG Vietnam Glass Industries is a wholly owned subsidiary of Nippon Sheet Glass.

Sand is transformed into huge sheets of glass! Sand is transformed into huge sheets of glass!

The sheet of glass on the cutting line is about 4 meters in length.

The sheet of glass on the cutting line is about 4 meters in length (above). VGI is in an industrial zone in Ba Ria-Vung Tau Province, southeast of Ho Chi Minh City, Vietnam's largest city. Many Japanese companies have factories here (left).

As countries around the world set about decarbonizing their economies by embracing renewable energy, they are increasingly turning to photovoltaic power generation.

One of the planet's foremost glassmakers, NSG produces glass for solar panels that capitalizes on its thin-film formation technology. The Group's global operations include wholly owned subsidiary NSG Vietnam Glass Industries (VGI), whose factory is devoted to the manufacture of glass for solar panels. Following the completion in January 2020 of a comprehensive refurbishment of its facilities, VGI is deploying NSG's industry-leading proprietary coating technology on its production lines. Since an in-person visit is currently out of the question, I visited VGI online to find out more about this company and its cutting-edge technology.

“VGI is in Ba Ria-Vung Tau Province, one of the few parts of Vietnam to which natural gas is supplied via pipeline. It's also close to a power station. So VGI is well-positioned to secure all the power it needs for the energy-intensive business of glass manufacturing,” says Mr. Kiyotaka Ichiki, VGI president. I was surprised to learn that VGI occupies a site of about 30 hectares. That is enough space to accommodate half a dozen massive sports stadiums. The 650-strong workforce includes three people dispatched from Japan.

President Ichiki says: “Vietnamese is a tough language to master. Even if you make an effort to study, it's a struggle to get to the point where you can communicate efficiently with Vietnamese colleagues on work-related matters. For conversing with managers and engineers, I tend to use English, which makes for much more effective communication than my Vietnamese.” He notes that contemporary Vietnam is in some ways similar to Japan during its period of high economic growth. Vietnamese employees, admired for their diligence and energy, are starting to enjoy increasingly affluent lifestyles as the country's dynamic economy continues to forge ahead.

Our products are exported from a nearby port on the Thi Vai River. Your products are shipped to the world. Our products are exported from a nearby port on the Thi Vai River. Your products are shipped to the world.

Anticipating Vietnam's economic growth and with an eye to satisfying rising demand in the domestic architectural market, NSG established Vietnam Float Glass (VFG) near Hanoi in the north of Vietnam in 1995 and VGI near Ho Chi Minh City in the south in 1997. Meanwhile, demand for photovoltaic power generation soared worldwide. It was decided in 2010 that VGI would focus on production of glass for solar panels and, in 2011, its first solar glass float line came on stream. Subsequently, another float line was upgraded and repurposed for production of glass for solar panels. The two float lines have been running at full tilt since February 2020.

Firing up the refurbished float production line in 2020.

Why did the switch to producing glass for solar panels necessitate a comprehensive refurbishment of the line? It was to make possible the introduction of NSG's world-renowned online coating technology. It was time for me to learn more about this fascinating technology.

Chemical vapor deposition (CVD) is one of the methods for forming thin coatings on glass so as to endow it with special functions. With NSG's online coating technology, thin coatings are formed on the surface of the glass as it travels along the production line. Hence “online.”

How is glass manufactured? First, take a mixture of ingredients, of which silica sand is the principal one, and melt it in a furnace. Next, pour the molten glass into a float bath of molten tin. The molten glass floats on the tin and spreads out, forming a level surface. Then, the molten glass cools to yield beautiful sheet glass. Online CVD involves applying various gases to glass floating in the float bath that trigger chemical reactions resulting in the formation of coatings on the glass surface. This epoch-making technology achieves cost-effective, high-volume production of coated glass.

Manufacture of glass for solar panels

A long ribbon of glass before cutting A long ribbon of glass before cutting

The ingredients, mainly silica sand, are heated in a melting furnace. Molten glass is poured into a float bath of molten tin to form a sheet. During this process, a transparent conductive oxide (TCO) coating is applied by CVD on the surface of the glass for the electrodes of solar cells. In the annealing process, flat, flawless glass is made.

Using online CVD, the optical properties of glass can be changed. For example, glass used for display cases in museums has a coating to minimize luminous reflectance so that from the viewer's perspective it is as if there is no glass. On the other hand, glass with high reflectivity akin to that of a mirror can be used for the display of images and text. Transparent conductive oxide (TCO)-coated glass, as well as being used for solar panels, is applied for thermochromic windows. In response to solar radiation, the clear glass windows change, becoming darker as the temperature rises, and thus dispensing with the need for blinds.

The production process for making glass with such remarkable properties must be different from the conventional way of doing things. “Yes. Specifications of the facilities are markedly different from those for the conventional process, from the furnace for melting ingredients to ejection of the finished glass. So, we needed to refurbish virtually the entire line from start to finish, which in some respects was trickier than starting from scratch. Also, we introduced new facilities compliant with Vietnamese environmental standards, which have become more stringent,” says President Ichiki. The NSG Group has six plants with online CVD facilities dispersed across four countries. People from these plants came to VGI to help with the refurbishment. The smooth completion of refurbishment was in large measure attributable to superb teamwork!

Finished glass is loaded into a dedicated container by a robot.
On the cutting line, glass is snapped into sheets of predetermined size.

By the way, almost 100% of the glass manufactured at VGI is exported. In fact, VGI accounts for a whopping two-thirds of the glass for solar panels manufactured by NSG. President Ichiki says: “As environmental issues become ever more pressing and capture the world's attention, we are proud and happy to manufacture TCO glass for solar panels that makes a valuable contribution to the reduction of CO2 emissions. Working together with members of the NSG team in Vietnam and around the world, we will eagerly embrace new challenges so as to offer the world great products that benefit society.” From now on, I know that whenever I see solar panels, in my mind's eye I will see President Ichiki and the talented, dynamic employees of VGI in Vietnam.

Aim at transparency like glass!

Some places in our plant get very hot. I'm drenched with sweat but my colleagues don't seem to feel the heat.
Some even find  25℃ cold. Things affect  different people  differently!
I guess there are  cultural differences too,  aren't there? Yes,  there was  a barrier.
But I feel at home here. Our job is to make the barrier transparent like glass. Well said!

Editor’s note

Online coating adds heat insulation, heat shielding, conductivity, and other desirable functions to glass. So this technology is not only great for solar panels but also useful for solutions supporting the progress of society, such as smart buildings, ZEHs (Net Zero Energy Houses), ZEBs (Net Zero Energy Buildings), and electric vehicles. New technology can transform our everyday life for the better, making everything far more convenient. That is the hallmark of monozukuri. Having listened to the explanation, I realize afresh how life-enhancing technology can be.
While talking with President Ichiki on my PC, in the background I see tropical trees stirred by the breeze, bringing the sunny atmosphere of Vietnam into my Tokyo room. It is also thanks to the progress of technology that I feel as if I am actually there.

Some 650 Vietnamese work at VGI. When the first solar glass float line was launched in 2011, hardly any members of the workforce had experience of glass production. In 2020, nine years later, as the second line came on stream, those original recruits, now experienced glassmakers, were training the latest intake of new recruits to VGI’s expanding workforce.

Number(Manga Reportage "Visits to Sumitomo Group")