If a mass-throughput unit is not essentially necessary, or not accurate because of too little material throughput, the user often chooses manual calibration. Thus the installed hardware is cheaper and more reliable. Generally, it should be the user's accuracy demands that assumes the decision. The PC's receipt handling supports the manual method, by recalling the same calibration during a later machine start-up procedure. This has been practiced by a few extruder line suppliers for a number of years.
Users often request only a die centering support as the key function of the system.
In that case, an absolute accuracy demand is not necessary. Also new is a system that compensates with software the influence of cooling water on the calibration. The accuracy statements of In-Line ultrasonic measurement systems can only be made when facing all the influences mentioned. The accuracy gained practically is dependant on individual conditions and covers a range from 0,02 mm - 0,10 mm.