Language: 日本語 | English
Language: 日本語 | English
High-precision and complex-shape processing of spring materials (SUS304, SUS631, beryllium, phosphor bronze, etc.)
We offer a comprehensive service, from considering shapes with 3-D diagrams to examining and proposing materials,
plate thickness and various processing methods, followed by testing, evaluation, progressive mold manufacturing and mass production.
We provide 100% support to speed up development for our customers.
Use our ability to make proposals, procure materials and cope with quick delivery when you have no time to spare between testing and mass production! In particular, leave fine, narrow, small, thin and complex leaf springs to us. Example: thin: 0.03, small: rice grain size, narrow: diameter 0.5.
Forging is a process that makes three-dimentional objects out of materials by crushing, exciting and other deforming procedures.
Various shapes are possible. Consult with us.
We also accept press stamping with dies produced by other companies. Put our ability to maintain dies and our quality assurance to good use. We have presses between 20 and 150 tons and can handle die sizes of up to 900 mm, plate thickness of 2 mm and materials width of 200. Materials include SPCC and SUS springs.
When manufacturing round shapes with press stamping there are two ways: curling and drawing.
Either method is available at our company.
We'll propose the optimal method keeping in mind the purpose for using the product, the required strength, the lead time allowed, etc.
A progressive die with a total of 25 processes, die length of 700mm, and a 150-ton press machine.
Material: SUS304CSP-1/2H (spring steel)
Thickness: t0.3mm
Processing elements included: Blanking, punching (round, square), right-angle bending, hemming, drawing, etc.
The more bending points there are, the exponentially more difficult it becomes to maintain overall precision.
We specialize in precision-demanding stamped parts with a high number of processes, from prototyping to mass production.
For more examples of complex-shaped products, click here:
https://www.kyowa-hearts.com/press/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■TEL:045-593-6116 FAX:045-593-6121
■Official website: https://www.kyowa-hearts.com
Material: Phosphor Bronze C5210R-1/2H, t0.15mm
Outer Diameter: φ2.3mm
Circularity: 0.03mm
At the customer's request, we designed a shape that secures the part inside the hole of the mating component.
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
Product Name: Sound Port (Hearing Aid Component)
Material: Phosphor Bronze C7521R-1/2H, t:0.1mm
Drawn Outer Diameter: Φ1.4mm
Product Dimensions: 3.2mm × 3.2mm
Total Height: 1.5mm
Key Points in Die Design:
Due to the non-circular drawn shape, innovative process design was necessary.
At Kyowa Hearts, we take on the challenge of new manufacturing technologies, including progressive deep drawing. This enables us to provide deep drawing as an alternative to conventional curling techniques for components requiring higher strength, offering customers greater flexibility in design and development.
We take full responsibility for the entire production process—from die design to final product—ensuring top-level precision and durability. With all operations, from prototyping to die design, manufacturing, and mass production, carried out at our Yokohama factory, we can respond flexibly and quickly to customer needs. Feel free to contact us.
For more deep drawing product examples, click here:
https://www.kyowa-hearts.com/sibori/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
Product Name: Reinforcement Plate
Material: Brass C2680R-H with Nickel Plating
Key Points in Die Design:
Due to the narrow U-shaped bending cam, special reinforcement measures were required for durability.
Key Points in Press Processing:
Angle adjustment is necessary when material lot changes occur.
At Kyowa Hearts, we specialize in micro, precision, and complex leaf spring processing.
We excel in manufacturing contacts and leaf springs for PC connectors and other electronic components.
Leaf spring processing requires a deep understanding of material properties, especially experience-backed data on springback behavior.
Once a drawing is ready, prototyping comes first.
We offer blanking processes such as laser cutting, wire EDM, and etching, followed by bending using temporary dies, allowing production from a single piece to 1,000 pieces.
For mass production, we utilize progressive dies to manufacture from 5,000 to over 1 million pieces—covering all production needs.
Feel free to contact us for inquiries.
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
Product Name: Contact Spring
Material: Beryllium Copper C1720R-1/2H, t:0.2mm
Key Points in Die Design:
Since the part is press-fitted into a pipe, special measures are required to achieve precise circularity.
Key Points in Press Processing:
As load management after heat treatment of the tip is crucial, strict dimensional control is essential during press processing.
At Kyowa Hearts, we specialize in micro, precision, and complex leaf spring processing.
We excel in manufacturing contacts and leaf springs for PC connectors and other electronic components.
Leaf spring processing requires a deep understanding of material properties, especially experience-backed data on springback behavior.
Once the drawing is completed, we start with prototyping. From 1 to 1000 pieces, using laser processing, wire EDM, etching, and bending with temporary dies for blanking.
For mass production, we utilize progressive dies to manufacture from 5,000 to over 1 million pieces—covering all production needs.
Feel free to contact us for inquiries.
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
Material: SUS304CSP
Thickness: t0.15mm
Processing Method: Press processing using progressive dies
It is possible to incorporate various processing elements into a small shape.
This product is a leaf spring with two contact points in different directions within a compact space.
When considering parts for weight reduction, multifunctionality, etc., please provide details regarding space constraints and required functions. We can consider the shape and make proposals.
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
【Product Specifications】
Thickness: 0.05mm
Material: Stainless Steel
Max Width: 2mm
Total Length: 3.6mm
Height: 0.7mm
Processing Method: Press processing using progressive dies
This is a low-load leaf spring designed to minimize applied force.
The die clearance is 2μm, which requires manual fine adjustments beyond the precision of machining tools.
Maintaining quality with minimal burrs is the key to press processing.
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
【Product Specifications】
Material: Phosphor Bronze
Thickness: 0.2
Shape:
φ1.9 (1 location)
φ3.7 (3 locations)
Total Length: 14
Application: Antenna Element
Precision in Concentricity & Coaxiality! Complex-Shaped Antenna Element
We successfully achieved concentricity and coaxiality within 0.03 for four interconnected circles of varying diameters, despite their unstable connections.
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
【Product Specifications】
Product Name: Leaf Spring for Socket Contact
Material: C5210R-H (Phosphor Bronze)
Thickness: t0.1
Total Length: 4
Inner Diameter:
Both Outer Sides: φ1.3mm
Center Section: φ0.8mm
Slit Dimensions: Width 0.3 × 6 slots
Roundness Accuracy: Within 0.05
Processing Method: Progressive Curling Processing
Key Explanation
Curling processing refers to the technique of rolling a flat sheet into a cylindrical shape.
The product shown in the image is a tsuzumi (drum) shape, where the center diameter in the length direction is larger than the diameters at both ends. Additionally, it is also possible to process a tawara (barrel) shape, which has a similar structure.
We can handle various spring materials, including phosphor bronze, beryllium copper, and stainless steel (SUS).
We have also successfully developed even smaller-sized components.
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
【Product Specifications】
Material: Brass C2680R-1/2H
Thickness: 0.64mm
Height: 4.5mm
Drawn Outer Diameter: φ4.6mm
Necked Section:
Outer Diameter: φ1.6mm
Inner Diameter: φ0.7mm
Processing Method: Progressive Deep Drawing
Key Explanation
Deep drawing is a forming process where pressure is applied to a sheet material to create a seamless, three-dimensional shape. This method is ideal for applications requiring airtightness and high strength.
Creating a necked section in the middle of the product presents a high level of difficulty.
Progressive deep drawing is well-suited for small, high-precision products. However, successful execution relies on experience and know-how that cannot be fully quantified.
For more examples of deep-drawn products, click here:
https://www.kyowa-hearts.com/sibori/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
Our company specializes in manufacturing components using micro-slit processing, micro-curling processing, and complex bending processing techniques. We have extensive experience in producing contacts and leaf springs for devices such as mobile phones, computers, and connectors.
Specifications
Material: C1720R-H
Thickness: t0.15mm
Inner Diameter of Both Narrow Ends: φ0.75±0.02mm
Outer Diameter of the Center (Wider Section): φ1.5±0.025mm
Total Length: 5.9±0.05mm
＊Additionally, our champion data is:
Material: C5210
Thickness: t0.05mm
Rolled Inner Diameter: φ0.3mm
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
Product Name: Connector Terminals
Material: C1100R-1/2H (ROHS Compliant)
Thickness: 0.2mm
Total Length: 2.9mm
Bending Angle: 135°
Expertise in Micro Precision Press Processing
Kyowa Hearts specializes in manufacturing thin, small, and narrow micro-press processed products. Our expertise particularly lies in the production of compact leaf springs and connector components for PCs and electronic devices.
From prototyping, mold design, and manufacturing to mass production, all processes are carried out in-house at our Yokohama factory, ensuring short lead times and flexible support to meet customer requirements.
We also have metal material specialists available, so please feel free to consult us regarding material selection or any other inquiries.
For more examples of leaf spring products, click here:
https://www.kyowa-hearts.com/spling/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
Material / Thickness:
Material: C2680R-1/2H
Thickness: 0.2mm
Processing Details / Precision:
Drawn Section: Outer diameter φ1.2, Height 3mm
Curling Section: Outer diameter φ7mm
Key Points in Progressive Die Manufacturing:
Ensuring that the φ1.2, Height 3mm narrow-drawn section is processed without tearing.
Designing the curling process to achieve roundness without using a core metal.
Key Points in Press Processing:
Proper handling of scrap from piercing the tip of the drawn section.
For more examples of deep drawing processing, click here:
https://www.kyowa-hearts.com/sibori/
☆ Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
☆ Equipment Information
https://www.kyowa-hearts.com/setsubi/
☆ Contact & Process from Prototyping to Mass Production
https://www.kyowa-hearts.com/flow/
＜Contact Information＞
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
■ Address: 1-5-1 Takata-Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
■ TEL: 045-593-6116 FAX: 045-593-6121
■ Official Website: https://www.kyowa-hearts.com
Material: Beryllium Copper C1720R-HM
Sheet Thickness: 0.15 mm
Curling Outer Diameter: φ1.1 mm
Post-Press Processing: Gold Hoop Plating
The product is the round component in the center of the image. The lower three-fifths of the vertical section is shaped into four blades, with their tips evenly and tightly pressed together.
To ensure the four blade tips are securely in contact, various techniques are applied, such as surface pressing around the blades and shaping them into a perfect circular form. The biggest challenge in the curling process is preventing twisting and eccentricity, as the connecting section to the carrier is only 0.3 mm wide and the pre-curling developed length is just 3 mm.
If you are facing difficulties with precision curling processing, please feel free to contact us.
Other Examples of Leaf Spring Products
https://www.kyowa-hearts.com/spling/
Frequently Asked Questions
https://www.kyowa-hearts.com/faq/
Equipment Information
https://www.kyowa-hearts.com/setsubi/
From Inquiry to Prototyping & Mass Production
https://www.kyowa-hearts.com/flow/
Contact Information
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
Address: 1-5-1 Takata Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
TEL: 045-593-6116
FAX: 045-593-6121
Official Website: https://www.kyowa-hearts.com
Introducing Load Testing / Load Measurement Services for Leaf Springs
At Kyowa Hearts, we specialize in the processing of leaf springs.
There are several key points in quality control for leaf springs, but load is one of the most critical factors.
To achieve sufficient load capacity, fine adjustments to the product shape and careful selection of materials are essential.
We have multiple load measurement machines in-house, allowing us to collect data during the prototyping stage to assist in selecting the optimal material and sheet thickness.
Additionally, during mass production, we can measure the load of leaf springs in real time and make fine adjustments to ensure product quality.
Even if you don’t have design drawings, no problem! Reverse engineering is also available.
Feel free to contact us anytime!
☆ Frequently Asked Questions:
https://www.kyowa-hearts.com/faq/
☆Equipment Information:
https://www.kyowa-hearts.com/setsubi/
☆From Inquiry to Prototyping & Mass Production:
https://www.kyowa-hearts.com/flow/
Contact Information
Kyowa Hearts Co., Ltd. – Rumi Sakamoto
Address: 1-5-1 Takata Nishi, Kohoku-ku, Yokohama, Kanagawa, Japan
TEL: 045-593-6116
FAX: 045-593-6121
Official Website: https://www.kyowa-hearts.com
