Showing papers by "Simon S. Park published in 2004"

On‐line measurement of the PVT properties of polymer melts using a gear pump

Abstract: This paper presents a newly developed experimental apparatus, based on an extrusion system, which can economically and accurately measure the pressure–volume–temperature (PVT) properties of polymeric fluids. The density or specific volume of a polymer melt is determined by measuring the mass and volume flow rates of the melt. A positive displacement gear pump mounted on an extruder is used to measure the volume flow rate of the melt. In order to reduce the leakage across the gear pump, the difference between the upstream and downstream pressures is minimized by using a variable resistance die attached to the downstream outlet of the gear pump. The positive displacement volume of a gear pump was determined in calibration experiments with water and oil with the aid of a syringe pump. Two critical sets of experiments were carried out to measure the specific volumes of polystyrene and polypropylene as case examples. The measured results were compatible with the known PVT data, confirming the validity of the system. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 316–327, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20020

Adaptive Control and Monitoring Using the Spindle Integrated Force Sensor System

Abstract: Applications of spindle integrated force sensors are examined where the cutting forces are reconstructed from the piezoelectric force sensors that are imbedded in the spindle housing. The reconstruction of the cutting forces using the disturbance Kalman filter effectively provides the high bandwidth sensor requirements. The three applications that are presented in this paper are Adaptive Control with Constraint (ACC), chatter detection, and tool breakage detection, all using the spindle integrated sensors. ACC provides effective means of increasing machining productivity through the adjustment of feed rates by constraining cutting forces. The detection of chatter vibration in machining operations is important in order to ensure quality surface finishes. The cutting forces measured from the spindle sensors provide sufficient information as to whether the cutting operations are stable or not. Tool breakage detection is performed using both a good tool and a damaged tool. Two residual indices based on the first order auto-regressive (AR) filter are examined to determine tool breakage. The experiments verify the successful monitoring strategies using the spindle integrated force sensors.Copyright © 2004 by ASME