Utilizing the two technologies to reduce costs and increase productivityKUMAGAI-SEIKI CO.,LTD.


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Sophisticated machining is possible using the two technologies.

Technology / service name = cold forging / precision shearing

"Cold forging" and "Precision shearing" require advanced technology and experience

"High precision" and "high quality" are keywords that symbolize Japanese manufacturing. These kinds of strong Japanese brands are supported by advanced, ultra-precision processing technology.

Kumagai Seiki has more than half a century of history in Nagano Prefecture, and offers two advanced processing technologies: cold forging and precision shearing. "Cold forging" involves performing molding while applying pressure to the metal in an ambient temperature environment. It results in less material loss and higher finishing precision than “hot forging” in which metalworking is performed in a high temperature environment. On the other hand, “precision shearing” (shaving) reduces unnecessary elements such as “sag” and “fracture surface” on the cut surface.

All of these technologies have great benefits, but providing them requires a high level of technical expertise and extensive experience. They can provide these two technologies individually or in combination. In addition to creating shapes that are normally difficult, it is also possible to control costs by changing the construction method.

Changing the construction method to reduce processes and control costs

The company's "cold forging" provides a specialized process within the progressive mold stage, which enables pressing including thinning and thickening of plate thickness up to 6mm. If this technology is utilized to change the conventional manufacturing method to pressing, the secondary process may be significantly reduced, lead time can be shortened, and the product unit price can be reduced.

In addition, "Precision shearing" can be applied in both progressive and single-shot styles, and the finish provides a shearing surface equivalent to FB (fine blanking) processing*. Although the technology struggles to keep the finished quality constant, the company has established its own "mold technology” through many years of pressing experience, and maintains a high-frequency maintenance and management system to maintain quality.

* Fine blanking: A high precision punching and shearing method that can achieve a processing accuracy of μms (1μm = 0.001mm).

Potential applications in all fields that require metalworking

Approximately 70% of current orders are related to automobile parts, among which there are especially many products with a plate thickness of 3.2mm or more such as automobile seats and doors. It is also increasingly used in the fields of notebook computers and industrial machinery.

However, the real advantage of both technologies is that they can be applied to all fields that require metalworking. There are elements of implementation you should get a handle on such as the benefits of larger lot sizes due to initial costs. You can consult them about this and also make a proposal for creating benefits including a cost comparison with existing construction methods and an initial amortization period.

They aim to convert their factory into a smart factory. In the near future the factory should be producing value-added technologies and competitive products that meet the needs of the world.

Coverage date July 1, 2019


Company overview


Integrated support from mold design/manufacturing to pressing. Also supports post-treatment such as heat treatment and plating through partner companies. By applying their original press technology, they can reduce the costs of various fields by providing pressing of cutting parts, eliminating secondary cutting, and integrated molding of multiple parts. One of their strengths is a fast response time that only small teams can manage.

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