Illustrator Ryoko Takagi visits Sumitomo Group
Tohoku Sumiden Precision

The principal site of Sumitomo Electric Hardmetal, a manufacturer of IGETALLOY carbide tools such as carbide drills and milling cutters, in Miharu-machi, Fukushima Prefecture. The company’s stirring slogan is “Flourish with people: From Miharu to the world!”

  • Tohoku Sumiden Precision

    Tohoku Sumiden Precision

    Manufacturing processes are computer-controlled.

Neat and tidy!

Opened in May 2017, the plant is proud of its excellent environmental performance. On-site photovoltaic systems and wind turbines help power the plant and surplus electricity is fed into the grid.

A40-minute drive from Kooriyama Station, Miharu-cho, whereTohoku Sumiden Precision (THS) is based, is midway between the three cities of Fukushima, Aizu-Wakamatsu, and Iwaki.

“This place gets its poetic name ‘Miharu,’ meaning ‘three aprings’ in Japanese, because the plum, peach, and cherry, the three trees heralding the arrival of spring, apparently blossom here simultaneously,” explains President Tanaka. He was one the people instrumental in opening THS in Fukushima. The 2011 Great East Japan Earthquake hit Fukushima hard, causing great damage.TSP’s decision to establish a service network in east Japan at Fukushima was in line with the business strategy. But the experience of parent company Sumitomo Electric Hardmetal, based in west Japan, during the 1995 Hanshin Awaji Great Earthquake gave a particular resonance to this commitment to helping the Tohoku region recover. Knowing how hard it is for communities to get back on their feet after an earthquake, the company was eager to assist Fukushima. Manufacturing operations at THS, founded in April 2016, were in full swing by November 2017. The employees, 80% of whom were born in the region, are proud that Fukushima is the source of made-in-Japan cemented tools synonymous with world-leading quality destined for the global market.

THS is pursuing initiatives to maintain its international competitiveness. Firstly, the company is fostering people capable of thinking issues through and taking the initiative. With this in mind, it is creating a workplace environment where employees are encouraged to question received wisdom, come up with KAIZEN proposals, and share awareness that each person has a responsibility to improve safety and efficiency through day-to-day activities. Indeed, KAIZEN proposals are being applied one after another. Secondly, it is trying to make the most of robotics and automation throughout the operation. This means robots and computers do the things at which they excel, with people issuing instructions and supervising. The idea is to optimize the division of labor between man and machine. Thirdly, Sumitomo Electric Hardmetal has established Tool Engineering Centers (TECs) around the world to offer services, such as training courses on the use of cutting tools corresponding to customers’ skill levels, test cutting, and technical consultation.

  • A cutting tool on which carbide inserts are mounted rotates at high speed to mill the side and bottom of steel parts.
  • A carbide insert mounted on a milling cutter.

A carbide drill in action.

Is it really hard? Is it really hard?

I was so impressed when I saw a drilling demonstration at the TEC at THS. First, the demonstrator drilled a hole in a block of steel using a high-speed steel drill of a type available at your local DIY store. He made a pilot hole before slowly drilling deeper.

Because of the heat generated by friction between metals, he sprayed on plenty of coolant. Since wood is the only material I have ever drilled, I was surprised that an ordinary drill can make a hole in steel. But what made my jaw drop came next. He changed the high-speed steel drill to a carbide one… Wow! The drill goes through the steel so quickly and easily. Is this the same steel as was used in the first demonstration? Yes it is. It’s like making a hole in an eraser or some other soft material. I couldn’t believe my eyes. And I couldn’t help but touch the steel block that had just been drilled.

Two neat holes were made swiftly and smoothly! The hardness of the drill makes such a huge difference. I know hardness varies according to the type of metal but I thought all metals were so hard they couldn’t be drilled without a struggle. So much for my common-sense view of the world!

Products made by Tohoku Sumiden Precision

Carbide drills
Milling cutters

Carbide drills for drilling automotive cylinder blocks and the likes (left). Milling cutters are replaceable carbide inserts mounted on cutting tools (right).

Next I visited the spacious workplace where carbide drills and milling cutters are made. A signboard bearing the directive “Stop, Call, Wait” caught my eye. Although the state-of-the-art manufacturing equipment is designed to ensure safety in the workplace, risk of injury can’t be entirely eliminated. “Safety comes first, not production,” says President Tanaka. Under his leadership, THS provides thorough safety training for employees, including training for new recruits before they actually start work at the company and periodic safety training thereafter.

Carbide contains valuable rare metals. So, THS recovers its products disposed of by customers and recycles the materials. Being considerate to people and the environment is good business practice not only ethically but also because it leads to lower costs while enhancing international competitiveness. The operation at Miharu reflects this recognition.

As THS's slogan says "Flourish with people: From Miharu to the world!," it may not be long before Miharu is renowned worldwide for the quality of its products.

This machining center equipped with a suite of 60 distinctively shaped tools makes milling cutters.

Working in tandem, two robots assemble products according to a plan determined by the computer system.

Signboard bearing the safety slogan.
A periodic safety patrol in progress.

A wide variety of carbide inserts for milling cutters.

They look like old coins from the Edo era! They look like old coins from the Edo era!

Thorough computerized progress control

This is where the products are made.
Work completed Work not completed 「What’s this?」 「It’s computerized progress control.」
This reminds me of something…
「I know the feeling!」 editor「don’t miss that deadline!」

Editor’s note

The material used for drills is very heavy.
A carbide chip for milling cutters is no bigger than the tip of your finger.

Long before visiting the site, we were all excited by the prospect of seeing a tool in action that is made of material so hard it can mill steel.

Though no bigger than a pen, the drill we saw at the plant was far heavier than you might expect. The carbide insert for milling cutters is the size of one’s fingertip.

What impressed us most was how swiftly the steel was milled using a CBN (cubic boron nitride) insert . The thousands of sparks produced during the milling of a steel bar rotating at a high speed by a CBN insert created a spectacular, though brief, display like a firework. Momentarily, there was a fiery disk of sparks. Ms. Takagi, struck by its beauty, exclaimed, “It’s unlike anything I’ve seen before”

A milling cutter shaping a steel bar.
The mockup of a milling cutter that Ms. Takagi received as a souvenir.
Ms. Takagi, fascinated by the milling cutter mockup.

The people at Tohoku Sumiden Precision were so pleased by Ms. Takagi’s passion for milling cutters that they presented her with a mockup of one as a souvenir. “Awesome!” she cried, smiling broadly as the rest of us admired the gift.

Number (Manga Reportage "Visits to Sumitomo Group")