Research at the Precision Engineering Consortium (PEC)
Turning has been the precision manufacturing method of choice over milling due to its combination of relatively short machining time and high-quality surface finish with single crystal diamond tools. However, one advantage that milling has over turning is the ability to uncouple the cutting speed from the material feed rate. The research underway at the Precision Engineering Consortium (PEC) is the development of a hybrid system that combines the advantage of milling and turning via a cyclic elliptical cutting motion. To this end, the Ultra Mill (UM), an in-plane (linear) elliptical tool servo, has been designed and built. Falling under the classification of Vibration Assisted Machining (VAM), UM research is also exploring the effects (tool-chip interaction) relating to duty cycle based cutting. A percentage quantity, the duty cycle is the fraction of the time per cycle that the tool is in contact with the material. Midway through its development, testing has shown that elliptical cutting has several advantages over standard cutting under identical machining parameters in the areas of surface finish and cutting force. As theorized, the ability both to uncouple part and tool speeds and to increase the projected tool cutting area, resulted in a 19% improvement in surface finish at part centers. The second advantage associated with the elliptical motion of the UM comes via a reduced cutting force. Closely following a PEC developed theoretical model of generated cutting forces, workpiece forces were reduced by as much as 50% verses standard cutting without any increase in surface roughness. The next step is the development of a high-speed version of the UM, ~8 kHz or 480,000 rpm equivalent. The effects of tool wear in elliptical milling and the potential of diamond milling of non-typical materials, i.e. steel and ceramics, will be investigated.
Spring 2000 Affilate Conference Presentaion (2.9 Mb)
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The following faculty, students, and PEC affiliates are involved in this project:
| Faculty | Students | Affiliates |
| Thomas A. Dow Ronald O. Scattergood |
Brandon Lane Meirong Shi |
National Science Foundation |
