This research activity is focused on improving machine tool system performance. One specific research activity is centered on the robust design of machine tool structures, a technique that optimizes performance in the presence of noise sources including those that are time-varying. Another effort is focused on the static and dynamic design/analysis of novel machine tool structures - in particular a Stewart Platform-based structure. Research is underway to model the damping performance of machine tools by characterizing the damping associated with the mechanical joints of the machine tool. Machine tool metrology and machine tool error modeling are other areas of investigation. It is envisioned that many of these research efforts can be incorporated into virtual model for machine tools on the World Wide Web.
The ability to position a cutting tool with respect to a workpiece is often desired to rectify positional inaccuracies/disturbances during a machining process. In a turning process, fast and precise repositioning of a cutting tool may permit the manufacture of unconventional workpiece shapes (i.e., non-circular cross-section) on a conventional lathe. Repositioning of the cutting tool may also be used to reduce vibration levels and improve the surface finish generated by the process. In this project, magnetostrictive and piezo-based actuation systems are being investigated for potential use in machining applications, e.g., turning, milling, and grinding processes. The goal of the project is to develop actuation schemes and control strategies for real-time active control of machining processes.
Markov Decision Process is a decision making tool in Operations Research. The research will combine principles of Life Cycle Analysis and Markov Decision Processes to achieve environmentally Conscious Decision Making. Markov Decision Process(MDP) is an application of Markov chains. MDP can be applied to any system which obeys the Markovian property. The Markovian property states that the conditional probability of a future state of a system does not depend on the past states of the system but only on the current state of the system. There are a few underlying assumptions involved in MDP. We plan to apply the MDP to a cutting fluid system. Cutting Fluids are very hard to maintain and dispose off. During the life cycle of a cutting fluid, the environment is harmed in many different ways, for e.g., fluid splashes cause skin irritation to workers, mist is generated which can on a long term basis affect the respiratory system of the workers. There is a growth in the number of bacteria in the cutting fluid which in turn increases the pH of the fluid. Disposal is another big problem. Straight oils are the toughest to dispose because they have to be broken down chemically before their disposal. Such degradation of the cutting fluid system will be modelled as discrete states and the economic as well as the environmental costs of different decisions and policies adopted during the coolant life cycle, will be determined. From these costs, the most optimal maintenance policy will be determined. This policy will not only be the most economical but simultaneously provide us with the least environmentally harmful policy.
Cutting fluids are widely used in machining operations to obtain accuracy of part dimensions, longer tool life and in some cases better surface finish. The research literature identifies two primary functions of cutting fluids in machining operations: lubrication to reduce process friction and cooling to remove process generated heat. A secondary function of the cutting fluid is to transport the chips from the cutting zone. Cutting fluid systems are used in industry to deliver fluid to the cutting process, recirculate fluid, separate chips, and collect fluid mists. A recent German study found that 16% of machining cost in the high volume manufacturing industries is associated with the use of cutting fluids in machining (procurement, maintenance and disposal) while only 4% of the cost was associated with cutting tools [Cselle, 1995]. The use of cutting fluids also requires additional equipment for plant housekeeping. Contact with cutting fluids has been shown to cause skin diseases such as dermatitis and some of the additives used to formulate cutting fluids may be carcinogenic. Mist is generated when cutting fluids are used in machining and inhalation of fluid mist may cause respiratory diseases among factory workers.Fundamental Research
Although much research has been done on cutting fluid action, much still remains undone. To date, no adequate model of mean heat generation/heat transfer in orthogonal machining exists. The non-coulombic friction mechanism on the chip/tool interface must be better explained. Much work on chip fluid carryoff and mist formation remains completely unexplored. Previously, an empirical approach has been adopted, merely stating what is occurring, and neglecting the why of the occurrence. No modeling of the process beyond simple empirical relationships can be performed until each mechanism of the machining process is better explained. Hereafter are the identified research issues we are working on: