In the manufacturing operation of pressure sensors, autofrettage denotes the process of active ?overload? by subjecting the pressure sensor selectively once or many times to a pressure above the nominal pressure range. This process is applied, in order to achieve maximum stability, in particular of the zero point, in later operation. Assuming a suitable design of the sensor, autofrettage enables a long time of trouble-free operation of the sensors even at high load cycles reaching the specified overload range, without leading to zero-point shift or similar effects.
In autofrettage, certain local areas of the sensor, where through the selective overload the yield point of the sensor material is locally exceeded, become plasticised, resulting in a permanent change of the instrumentation characteristics. This selective influence on the structural conditions by way of autofrettage can be an integral portion of the development of the sensor and of the associated manufacturing process. Which pressure the sensor is put through and how often, should be determined individually for every sensor design through a complicated FEM simulation and extensive test series.
Caution ? no experiments of your! However, it should not be concluded that every sensor will automatically benefit from subjecting it to autofrettage. Autofrettage can only just be utilized for ductile materials, but for no reason for brittle ones. Conditioning must be scheduled and completed very selectively sufficient reason for great care during the production stages. Ill-considered ?overpressurising? of เกจวัดแรงดันลมราคา by laymen who like experimenting can not only damage the sensor permanently, but additionally result in dangerous preliminary damage and subsequently possibly in accidents due to fatigue and bursting of the sensor. In this manner, an improvement in instrumentation is only going to be achieved, if, by hit or miss.