SOHWA SEISAKUSHO Co., Ltd.

A precision press company specialising in fasteners

Sowa Manufacturing is a manufacturer possessing proprietary technology for ultra-small lock nuts. With a minimum nominal diameter of 1mm, it boasts the world's smallest class for press-formed lock nuts. Relying on this precision technology, technical enquiries such as ‘Could you make something like this?’ are pouring in from across the nation. The source of this consistently innovative technology lies in its deep expertise in deep-drawing processes, including die design. Specialising in fastening components such as nuts and washers, the company also handles small precision parts for medical equipment and electronic devices, supporting a wide range of industries.

In-house die production contributing to cost and quality

The intricately curved small components are completed by pressing a single sheet of metal multiple times. Sales Manager Shinya Sawahashi expresses confidence in the high level of this technology, stating, ‘When our experts in pressing see our sample products, which show the changes made at each stage, they are amazed.’ Cracking and wrinkling are the greatest enemies in press drawing. This is because the company achieves complex shapes where suppressing these defects is considered extremely difficult.
The amount of draw per operation is optimised for each material's properties, preventing cracking while maintaining efficiency. The company is acutely aware that customer selection hinges not only on precision forming technology but also on cost, stable mass production, and shortened lead times. Consequently, it handles mould design, manufacturing, and maintenance entirely in-house. By eliminating the need for mould transportation and waiting times associated with outsourcing, and by swiftly handling maintenance internally for wear or unexpected repairs, the company has established a system that thoroughly minimises downtime. This also enables flexible design changes and prototyping support during the product development phase.

Strengths

The Super E Nut, featuring a screw hole diameter range of 1.0 to 1.4 mm, employs a hollow structure and spring material elasticity to absorb vibration, symbolising the company's technological prowess. Through a 15-step pressing process and a proprietary thread-forming machine, it achieves multiple high-level characteristics: non-loosening, ultra-compact size, high precision, and lightweight construction.
Furthermore, the bolt possesses load-distribution characteristics, thereby reducing localised fatigue in the bolt and stress on the fastening materials. Consequently, it has been adopted by various premium eyewear brands based in Sabae City, Fukui Prefecture, one of Japan's foremost eyewear production hubs.

SOHWA SEISAKUSHO takes pride in its product range, which, while appearing structurally similar to competitors' offerings at first glance, achieves unparalleled performance. The “Stable Nut”, widely used in automotive and construction applications, employs a three-bladed spring ring that applies high pressure to the bolt threads, delivering stable anti-loosening effects.
Moreover, the ‘Speed Nut’ used for installing interior components such as insulation materials, features a structure that secures simply by pressing in, rather than requiring rotation. Meticulously calculated claw angles and shapes ensure it is difficult to pull out yet easy to press in, earning it a solid reputation among users.

Message from President

SOHWA SEISAKUSHO is committed to creating high-quality, outstanding products under the corporate philosophy of ‘striving for the prosperity of a more affluent society’. We aspire to become an industry benchmark through the development of unique products, and our guiding principle is to comply with societal rules and act responsibly.

Major Equipment

• Automatic presses for sequential feedingPXL110, etc.
  Washino, etc.16 units
• Cross-shaft power pressesPUX-110, etc.
  AMADA, etc.10 units
• Press for manufacturing stable nutsTP-45X, etc.
  AMADA, etc.7 units
• Surface grinding machineSG-64F and others
  AMADA, etc.6 units
• High-speed wire electrical discharge machineAQ537L, etc.
  Sodick, etc.2 units

Company Overview

Company Name

SOHWA SEISAKUSHO Co., Ltd.

Address

3-7-26 Wakamatsu-cho Higashi, Tondabayashi-shi, Osaka 584-0023

Company President

CEO Hiroshi Okagaki

Founded / Established

May.1948/January.1957

Number of Employees

26　

Phone

0721-25-7021

Fax

0721-24-9213

E-mail

shimazaki@sohwa-s.jp

Official Website

https://sohwa-e-nut.com/

Capital

10,000K JPY

Certifications

ISO 9001