In dumbbell-type tensile testing for rubber products, specimens must meet strict standards for thickness and shape.
Our slicing machine, the NP-120RS, has been widely used by Japanese rubber and automotive parts manufacturers, recognized for its stable accuracy and quality.
This article introduces how it solves specimen preparation challenges, with real-world examples of its impact.

What is Dumbbel -type  Tensile testing for Rubber ?

Dumbbell-type tensile testing is a commonly used method for evaluating the quality, material properties, and mechanical strength of rubber products in quality control, material testing, and R&D.
In this test, rubber specimens are stretched until they break to measure their tensile strength. The specimens must conform to strict standards for shape and thickness.
While test pieces are usually cut from unprocessed materials, the ability to precisely slice them from molded or finished rubber products allows for more realistic and application-specific evaluations.

Challenges in Rubber Dumbbell Specimen Preparation

　〇Complex shapes make it difficult to extract uniform specimens

→Tire treads, cable sheaths, and anti-vibration rubber parts are often molded into complex shapes with irregular surfaces, curves, or non-standard geometries.
As a result, it is difficult to extract smooth, uniform test specimens that meet standard specifications.
This challenge becomes even more critical when testing under actual usage conditions is required, as conventional methods often struggle to process such intricate shapes with sufficient accuracy.

〇Thickness variations and poor surface finish reduce test reliability

→In dumbbell-type tensile testing, it is essential that the specimen has a uniform thickness and a smooth slicing surface with low surface roughness.
Manual processing or low-precision equipment often results in thickness variations and rough cut surfaces, which can lead to significant inconsistencies in test results.
As a consequence, it becomes difficult to perform reliable and repeatable quality evaluations.

〇Manual slicing is dangerous and inefficient

→In many production environments, test specimens are still prepared manually using paper grinders or cutters.
This method not only results in significant variability and poor reproducibility due to inconsistent cutting precision, but also poses safety risks because it involves handling sharp tools.
Additionally, the manual process is time-consuming, as each specimen must be prepared individually, which increases the overall workload and significantly reduces productivity.

〇High material loss due to low yield

 →In tensile testing, it is necessary to obtain test specimens that conform to specific dimensions, shapes, and thicknesses as defined by international standards .
However, molded rubber products often have irregular thicknesses and shapes, which limits the usable areas for specimen extraction and significantly reduces material yield.
In the case of complex or non-standard geometries, large portions of the material must be trimmed or repeatedly processed to obtain specimens that meet the standards, resulting in substantial material waste, increased costs, and extended preparation time.

Solution: High-Precision Slicing with NP-120RS

■what is High-precision slicing with NP-120RS？

The NP-120RS is a high-precision slicing machine designed specifically for rubber, sponge, and soft foam materials.
It enables users to prepare dumbbell-shaped test specimens with consistent thickness, smooth surface finish, and minimal material waste.
Unlike manual cutting methods that rely on operator skill, the NP-120RS ensures repeatable slicing accuracy　, improving both the efficiency and reliability of tensile testing.
This equipment has been widely adopted by major manufacturers in Japan, including automotive parts makers, cable producers, and rubber processing companies.
It is trusted for meeting the strict quality requirements of the Japanese market, and is now available for global customers seeking reliable test specimen preparation.

■Key benefits

　〇Consistent slicing thickness from 0.3 mm to 3.0 mm
　〇Compatible with irregular-shaped molded rubber parts
　〇Reduces manual workload and safety risks
　〇Proven in Japan’s high-standard testing environments

Case Studies (Tire, Cable, Packing, Anti-Vibration Rubber)

Case Study①　：2mm-Thick Specimets from Tire Rubber 

We successfully performed precision slicing to extract 2mm-thick test specimens from molded tire products, including tread surfaces with complex textures.
The NP-120RS is compatible with rubber materials used in passenger vehicles, trucks, and motorcycles—each with different structures and properties—meeting the specific testing requirements of various tire manufacturers.

Case Study②　：Slicing from Arched Cable Sheath Rubber

We sliced arched rubber test specimens from cable sheaths after removing the internal wire core.
Even though the shape was curved and non-flat, the NP-120RS achieved precise thickness and stable specimen quality from these irregular materials.

Case Study③： Selective Layer Slicing from Water Pipe Packing

We used the NP-120RS to precisely extract only the necessary rubber layer from multilayered water pipe packing materials.
Even in complex composite structures, the machine enabled selective slicing of layers with the desired mechanical properties—something that is highly valued in fluid sealing applications.

Case Study④　：Multi-Step Slicing of Engine Mount and Anti-Vibration Rubber

For irregular-shaped, stiff rubber components like engine mounts and vibration isolators, we performed multi-step slicing to reach a final uniform thickness of 2mm.
This method enables consistent test specimen supply and supports quality control efforts for automotive part manufacturers.

Case study⑤　：Flattening and Slicing from Textured Shoe Soles
From rugged soles of safety shoes and sneakers, we removed the textured surface and produced flat, tensile test-ready slices.
By replacing time-consuming manual grinding with automated slicing, we reduced labor time by approximately 60% and significantly improved worker safety and consistency.

■Specification(NP-120RS) & Application Field

■Main Application Fields 

• Tires, cables, packings, anti-vibration rubber, and shoe sole materials

• Semiconductor materials, chemical products, and LCD panel components

• Industrial sponges, nonwoven fabrics, gelatin, and similar materials

• Soft, low-density, highly viscous, and flexible materials

〇Silicone rubber was successfully sliced from 4 mm down to 0.4 mm thickness.

〇Foam material was sliced down to a minimum thickness of 100 μm.

〇Achieved a surface roughness of Ra 3.2 on urethane rubber.

Company Profile

• Company Name: Nippy Machinery Co., Ltd.
  Head Office　　: 767-1 Shimomiyaki-cho, Kasai City, Hyogo, Japan
  Founded　　　　:1947
  Business Fields:Slicing machines for rubber and foam materials & Equipment for preparing dumbbell-shaped test specimens,Leather processing machinery
  Patents:　４Japanese patents ,1 internat
  Awards:2023: “Director-General Award of the Small and Medium Enterprise Agency” by the Japan Machinery Federation
  2024: “Invention Merit Award” at the Japan Invention Grand Prize

• Website: 　https://www.nippy.jp/en/index.php

  　

  

Contact & Next Steps

If you are interested in a slicing sample or a live demonstration of the machine, please feel free to contact us.
We support your implementation process through the following steps:

• Trial slicing with your sample material

• Evaluation and feedback from your team

• Detailed specification discussion

• Quotation and order placement

• Manufacturing, factory acceptance test, delivery, and commissioning

If you would like to learn more about our slicing technology, we also provide in-depth technical documentation.
You can download it from the link below.

バックナンバー

発泡体スライス技術 – 軟質素材をミクロン単位で精密加工

高精度発泡体スライス加工 – TPOシートと発泡体の精密分離

研磨材用羊毛バフフェルトを薄くするスライス加工-10ｍｍ→4.2mm±0.05

ウレタンスライス加工事例-発泡ウレタンフォームを0.3㎜に精密スライス加工

ゴムスライス加工事例 – 未加硫ゴムをミクロン精度でスライス加工

【ミクロン精度の加工事例】名刺を100μmの薄さに高精密スライス

【ミクロン精度のスライス加工事例】葉っぱ200μmを究極の薄さに加工

【ミクロン精度のスライス加工事例】キッチンペーパーを0.1㎜に精密スライス加工