Abstract: A sample grinder includes a base having a bowl and a rotatable drive plate to operably support a grinding wheel. A head is configured to support a specimen holder and has a first drive for rotational drive of the specimen holder and a second drive for moving the head and specimen holder toward and away from the drive plate. The head has a sleeve that is larger than the specimen holder. A cover is disposed over the bowl and has an opening larger than the sleeve so that the sleeve fits through the opening when the specimen holder is moved toward the rotatable drive plate. The grinding wheel is mountable to the plate in a single radial orientation only. A dressing system is operably connected to a controller to monitor the current of the drive plate motor and/or the head first drive actuates the dressing system based upon the current drawn by the drive plate motor and/or the head first drive motor falling below a predetermined value.

Abstract: A control system for a dynamic extruder wherein the pressure of the plastic melt is monitored and compared to a set point. When the melt pressure is equal to or greater than the set point, the supply of plastic to the extruder is halted, thereby preventing any increase in melt pressure and thereby precluding rupture of the extrusion die due to excess pressure.

Abstract: The temperature profile established across a heat exchanger, such as employed on an extrusion die, for example, is controlled by introducing fluid into the heat exchanger at a predetermined temperature. The temperature of the fluid withdrawn from the heat exchanger is measured, and the rate of flow of fluid through the heat exchanger is controlled in response to the measured temperature to maintain the measured temperature at a predetermined value.