High Speed Videographic Quick Stop Device for Orthogonal Machining

Abstract

Advances in digital high speed video acquisition make it possible to create a fully integrated virtual quick stop device to observe the orthogonal metal cutting process in real time. This research aims to provide additional information and updated imagery to aid in the development of a predictive theory of the metal cutting process. Existing shear zone models are applied to force data paired with high speed video footage to see if these models accurately predict the way in which metal is deformed during orthogonal machining. A high speed videographic quick stop device was developed to observe the metal cutting process. This system allows force data from a dynamometer to be paired frame by frame with the imagery from a high speed camera. Frame rates as high as 1,000 frames per second were used to obtain a high resolution data set for analysis. The images of highly polished and etched metal surfaces allow the researcher to see how the grain structure of the metal deforms in front of the tool edge as it moves through the material. The angle at which the grain structure deforms can then be measured. Analysis of the data indicates that the plane in which a metal undergoes plastic deformation is affected by the material properties of the metal samples and the cutting factors (tool angle, feed, etc.) used. The hardness value of a metal undergoing the metal cutting process has been shown to have a significant effect on the resulting angle at which it will plastically deform. Copper 101, Aluminum 1100, and 1018 Steel were the materials used for this study. The hardness of these metals was increased by cold rolling. Tensile samples were cut from each unique metal sample and tested for precise material property values. Customized high speed steel (HSS) tools at three different rake angles were used for the orthogonal machining of the metal samples. The utilization of a fully integrated, computer controlled cutting environment in conjunction with the high speed virtual quick stop device permits the collection of a highly synchronized data set for all parameters being studied. A statistical analysis of this data provides the additional information on the shear process under orthogonal metal cutting conditions. The better understanding of the metal cutting process can aid in improvements to the control of metal machining processes.