According to different applicable objects, the rubber hardness tester mainly comprises three categories: type A, type C (AO), and type D. Their measuring principles are precisely same. The difference is that the size of the measuring needle. The diameter of the needle tip of Shore A hardness tester is 0.79 mm, which is used to measure soft plastic, rubber, synthetic rubber, felt, leather. The needle tip diameter of the Shore D hardness tester is 0.2 mm. That is, the radius is R0.1. Type D is used to measure the hardness of hard plastics and hard rubber, such as floor materials, bowling balls, and other plastic plates. The Shore C (AO) hardness tester’s test pin is a ball with a diameter of 5 mm (R0.25). Type C is used to measure soft materials such as foam and sponge.
- Type A durometer is suitable for general rubber, synthetic rubber, soft rubber, polyester, leather, wax, etc.
- Type C (AO) durometer is applicable to rubber and plastic containing foaming agents made of microporous materials with low hardness.
- Type D is applicable to harder rubber, resin, acrylic, glass, thermoplastic rubber, printing plate, fiber, etc., which have higher hardness.