【Do You Assume Fracture Surfaces Are Unavoidable?】
In press blanking, fracture surfaces are often considered inevitable.
However, in precision components such as gears, fitting holes, and sliding parts, they can cause accuracy loss, wear, noise, and looseness.
Although fine blanking offers high-quality shear surfaces, its cost and limitations can be restrictive.
An effective alternative is precision shearing using general-purpose presses.

【What Is Precision Shearing】
〈Maximizing shear surface by suppressing fracture〉
Precision shearing applies high constraint pressure to reduce fracture and increase the smooth shear area, ideally achieving full-shear through the thickness.
Benefits:
・Improved surface finish
・Stable perpendicularity and accuracy
・Reduced burrs
・Enhanced fitting performance
It also enables reduction or elimination of secondary machining processes.

【Achieving Full Shear with General Press Machines】
〈Precision without dedicated equipment〉
Full-shear can be achieved with general press machines by optimizing die design and process conditions.
Kawamura Kikai Co., Ltd. leverages extensive press expertise and 50 machines (10–500 t) to develop precision shearing on standard presses.
At the prototype stage, full-shear has been achieved by optimizing:
・Clearance based on material and thickness
・Die geometry for material flow
・Die rigidity
・Pressing conditions

【Manufacturing System and Capabilities】
〈Flexibility through in-house die production〉
With 70+ years of experience, the company handles die design, manufacturing, and maintenance in-house, enabling fast improvement cycles for:
・Prototype optimization
・Mass production durability verification
・Wear-based die modification
Additional processes such as spot welding, riveting, and assembly are also supported, allowing optimization at the unit level.

【Typical Applications】
Precision shearing with general presses is effective for:
・Gear and tooth-profile components
・High-precision hole brackets
・Thin sheet parts requiring strength and fit
・Mass-production parts targeting machining reduction
Stable shear surfaces reduce burrs and variation, improving assembly stability and productivity.

【Key Considerations When Evaluating Precision Shearing】
When considering precision shearing, the key question is not whether specialized equipment exists, but how well processing conditions can be designed.
Important factors include:
・Current shear surface ratio
・Impact of fracture surfaces on part functionality
・Potential to reduce secondary machining
・Dimensional stability in mass production
Even at the prototype stage, feasibility studies based on drawings or existing parts can help identify optimal processes.

【Summary】
Precision shearing is not only about higher accuracy, but also about improving overall manufacturing efficiency and quality stability.
With optimized die design and processing conditions, it is possible to approach full-shear results even with general press machines.
If shear surface quality or machining reduction is a concern, reviewing the forming process may provide a practical solution.

【Contact Information】
Kawamura Kikai Co., Ltd.
Head Office: 2-4 Shimizu-cho, Itabashi-ku, Tokyo 【Composite Division】
Hanazono Factory: 10 Kitane, Fukaya-shi, Saitama 【Metal Press Division】
Website: https://www.kawamura-kikai.co.jp
Inquiry / Quotation: https://www.kawamura-kikai.co.jp/contact/
Consultations regarding precision shearing and full-shear processing using general press machines are available from the early planning stage. Sharing drawings or current challenges will help identify the most suitable processing method.