Testing of liners and measuring material properties

The milking liner is often considered as one of the most important parts of the milking machine, since it is the only direct contact between the machine and the cow. The interaction between liner and teat determines to a large extent the performance of the milking machine. Therefore liner performance is of great concern both from an economical and herd-health point of view. A lot of studies have attempted to investigate the relationships between the physical and the milking characteristics of the liner, however the manufacturing of the ideal liner still seems to be an enigma. The results of many liner experiments show that liner design has a greater effect on milking characteristics than any other machine factor. Six-fold differences in strip yield; eight-fold differences in the incidence of liner-slips and 33% differences in machine on times between liners are evident. The main question is how to measure liner performance for 'real life', for example, the benefit of the farmer. Several tests for liners are available. They range from common acceptance tests performed by the manufacturer to control the quality of the product, tests to measure physical characteristics of liners and tests to measure the milking characteristics of liners. For a complete validation of the characteristics of a liner, several tests have to be included.