Prise winners list

Development of 'Tube Forming System' revolutionizing the manufacturing of metal pipes for automobiles

Higashi- ward, Hamamatsu-City
Kunimoto Kogyo Corp.
Other award winners
Mitsutoshi Ichikawa, Tomohiro Uchiyama, Hiroki Kunimoto, Shoji Matsuo
Recommended by
The Hamamatsu Chamber of Commerce and Industry

Kunimoto, Yukitaka  (62)

We thought, "Anybody can perform this work". However, actually it was the work only our own technology could perform. When we learnt of this fact, our new challenge started.

"If we form a metal gently and smoothly, it can be formed into any shape." Based on this concept, this company has established its "Tube Forming System" that combines the respective processes for bending the metal pipes for automobiles, tube expansion and shrinking, forming and thickness control and automates those processes. Its technology for forming the pipes with the dies has improved the flexibility for design and drastically reduced the production cost. This new technology can be used for iron and other metals such as titanium, aluminum, stainless steel and carbon steel. The company supplies its products to automakers and parts makers including Toyota, which assessed the company's technology highly ahead of other companies.


"We cannot buy an expensive machine." We acquired our own technology only one in the world through trial and error.

Many metal pipes and tubes are used around the engine and in the exhaust system of an automobile. Most of the pipes are not simple "straight round" ones. They are bent, twisted and swollen in some sections. There is even a long pipe called "inlet water pipe", which flows cooling water and the surface of which is irregular as if it was struck with a hammer randomly looking like an avant-garde art product. Some sections of that pipe are intentionally dented so that other parts can be mounted effectively. 

Conventionally these pipes and tubes have been manufactured in die casting or in the "bending with bender" method in which both ends of a pipe gripped and its center is bent to have an angle. This company has developed its own technology for "press forming a pipe with a die". Making use of the properties of metal that "a metal can be extended and formed in any shape", force is applied to a pipe from various directions to form it into the intended shape. 

"Although our knowhow is a secret, in this new method, we can freely perform "minimum bending", which bends a pipe at a sharp angle, and "continuous bending", which bends a pipe without any straight section between two bending sections. It is very difficult to perform this continuous bending in the conventional "bending with bender" method. Our new method has drastically improved flexibility for design. By extending, shirking or drilling metals, the new method enables us to manufacture parts in integral molding, which was conventionally manufactured by welding. The new method has clear merits such as reduced cost and weight of products even when compared with casting.

The company started machining of pipes with dies in 2001. In that year, its major business partner, a giant motorcycle maker, expanded its overseas production and stopped purchasing the parts from the company. 
"I was so concerned about our situation that I thought I would terminate my family business. However, my son said, "I wish to work with my father to manufacture products." I could not terminate my business because my son wished to succeed my business. Mr. Kunimoto gave up production of motorcycle parts and determined to enter the more potential automobile industry. Fortunately the company received purchase orders from an automobile parts manufacturer who was impressed by its technology. The company was asked to "bend pipes".

"Why did we try to bend pipes by press work? Because we could not buy an expensive bending machine. Therefore we tried to bend pipes with our existing pressing machines. Needless to say, however, we could not bend the pipes so easily. It took us ten months to bend them somehow, but they were all defective products. Some of them did not have enough thickness in certain sections, and the sections, which had to be a true circle, were crushed flat. It took us several more months to manufacture the products successfully, and we completed our production line only one month before production of automobile was started.

We must produce high-quality products in automatic mass production. Then we can manufacture products competitive with those manufactured in the emerging countries.

We have acquired this technology with many efforts. However, we simply thought, "Anybody can accomplish this if they work hard". 
When a responsible person in Toyota said at an exhibition in 2005, "This is an amazing technology", we became aware for the first time that our technology was an epoch-making one for manufacturing. 
"Honestly we thought at first that pipe manufacturing was not so required for an automobile. However, as we heard more about automobiles, we learnt that our technology could reduce weight of products and improve strength of them. 

Impressed by the technology of this company, Toyota started a direct business transaction with it exceptionally, not through any parts maker. The company also acquired higher technology while challenging to meet customers' difficult requests. Mr. Kunimoto focuses on the technology for forming the pipes into any shape, automation and laborsaving in his factory. His factory now operates "Tube Forming System", in which one worker can operate eight work processes. The manufacturing machine for it was also made by his factory.
"The existing machines can manufacture only the products which other companies can also manufacture. Our company devises our own work method and manufactures good products at low cost quickly. We will continuously pursue this policy named Kunimoto Model." We will further improve production speed and will pursue laborsaving so that one worker can operate twenty work processes. Mr. Kunimoto says confidently, "If we can achieve our these goals, our products will be surely superior to those made in China and other emerging countries."

Kunimoto Kogyo Corp.

May. 1970
20 million yen
61 (as of Dec. 2009)
Brief information:
Established as a manufacturer for motorcycle stands. The company converted its business from the motorcycle sector to the automobile sector and established its technology for press forming of the pipes.

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"Based on the concept that a metal can be formed in any shape," the workers form the metal pipes freely. This is the manufacturing technology we thought readily available but actually it was not.


Bending a pipe again just after bending it once. In this method, we can perform bending of a pipe very easily, which could not be performed by the conventional "bending with bender" method.


Automobile parts called "turbo oil tank" and "inlet water". The parts in Mr. Kunimoto's hand are the products of his company. They are smaller, lighter and lower cost than the cast products.