For most materials such as hardware and plastics, hardness and softness directly determine product value and functionality. Materials with different hardness levels vary in price and quality, and their soft or hard properties decide whether a product can work as designed. Like metal and stone, silicone is refined and compounded artificially instead of being natural minerals. Different hardness requirements also lead to distinct production processes.
This also applies to the silicone products industry. Many consumers struggle to distinguish silicone hardness. During product design and development, it is often hard to confirm the proper hardness to meet functional demands. So how to select the right hardness for silicone products?
The hardness of silicone determines assembly performance as well as cushioning and shock absorption effects. The conventional hardness range of silicone products across various industries is 20 Shore A to 80 Shore A. With the advancement of material R&D in recent years, the maximum hardness can now reach 90 Shore A. The standard hardness tolerance is ±5 Shore A, and premium raw material suppliers can control the tolerance within ±2 Shore A. For certain products, hardness accuracy is critical to their normal function.
The majority of compounded silicone rubber products feature a hardness between 40 Shore A and 60 Shore A. Unlike metal materials, silicone has relatively wider tolerances for hardness and dimensional precision. Manufacturers that can strictly control the hardness and dimensional tolerance of finished silicone products require sophisticated production management.
Characteristics of High-hardness Silicone
Higher silicone hardness means greater brittleness and higher tear tendency. Products with high hardness are prone to cracking at mold parting lines and burrs. Product structure is therefore extremely important. For items with complex structures, undercuts or right-angle designs, damage may easily occur with improper use. To guarantee yield rate and service life, high-hardness silicone products are generally designed with simple structures. Overly complex designs will result in lower production yield and shorter service life.
Characteristics of Low-hardness Silicone
Low-hardness silicone has opposite properties. It is suitable for complex structures and easy to process, with excellent ductility and resilience. However, it may tear when stretched, which is also related to raw material quality. During production, low-hardness silicone is likely to suffer from incomplete curing and excessive softness. In service, stress on bevels or right-angle positions can also cause breakage.
Silicone products of different hardness serve different purposes. The optimal functional performance is achieved at a hardness of 30 Shore A to 70 Shore A. Hardness that is too high or too low will complicate processing, raise production costs and reduce production efficiency.