Everything has two sides, with its superior performance, while there are less than undeniable. Rubber joint material as engineering material, its main drawback is the strength and modulus of elasticity of metal is much lower, the use of low temperature, and easy to aging, while the different varieties of rubber in performance is vastly different; so in the selection, design manufacture of rubber parts and other engineering materials as well, so take full note of how a reasonable selection problem. Consider the use of the environment, process, cost and so on.     The first consideration is the use of parts of the environment and working conditions, to meet its performance requirements, which is the basic principle of material selection;
Secondly processing properties of the material, suitable for mass production, to ensure product performance, size, consistency;
Costs, due to the difference between organic sources of raw materials and ingredients, the price is very different;
Reliability, engineering materials due to their differences in the use of the environment, particularly rubber conditions of use and its own reasons, usually easier to fail than other parts.