With the idiamCONTROL measurement system from Micro-Epsilon, measuring the inner diameter of drilled holes in the housings of double worm extruders is now much easier. This instrument has been specifically designed for checking bore diameters by using non-contact capacitive displacement sensors.
To measure the diameters, the sensor unit is inserted into the housing bore of the extruder and pushed as far towards the upstream end as possible. The measuring technology gauges the clearance to the housing bore wall using non-contact distance sensors positioned opposite one another. The distance signals from the sensors are converted in the controller to provide diameter values. These diameter values can be recorded by turning the cross rollers through 40°, for a total of six measuring tracks in a double worm extruder. Guide bolts, which run along the saddle of the two bores, ensure that the measuring tracks are adhered to exactly. While retracting the sensor unit, the evaluation unit records and stores the diameter measurements and the distance covered. Data transfer to a PC for archiving and graphical evaluation purposes is performed by using an RS232/USB interface. The values recorded can be displayed as diameters over the complete length of the bore, and any tolerance deviations are immediately displayed.
Measurement is conducted over the entire length of the extruder, as it is not necessary to dismantle the processing sections. This leads to significant time savings. The idiamCONTROL system helps to optimise the maintenance work on the extruder housings. Service intervals can be accurately planned due to precise knowledge of the condition of the housing bores at any particular point.