This Is AuburnElectronic Theses and Dissertations

Slow Speed Orthogonal Machining of Polycrystalline FCC BCC HCP Alloys at Various Levels of Hardness using Gaseous Coolants




Carter, James Michael

Type of Degree

Master's Thesis


Mechanical Engineering


A statistically designed slow speed orthogonal machining experiment was conducted to compare the effects of various metal-working gases upon the cutting process. Several metals with different crystalline structures and materials conditions were utilized (face centered cubic aluminum alloy 6061 with three tempers (T0, T4 and T6), close packed hexagonal AZ31B at two tempers (H0 and H24), and body centered cubic steel alloy 4130 at three levels of hardness (22, 32, and 42 HRC). A single tool material of High-Speed Steel (HSS) was utilized with three different tool rake angles () of 25°, 30° and 35°. The cutting fluids utilized were air, argon, and nitrogen. Classic Merchant Force Diagram (MFD) data was collected using a Kistler force Dynamometer and processed using LabVIEW software. The tools were pushed through the 2” long x 0.125” thick piece of stock material at two different depths of 0.004 inches and 0.008 inches. After 10 inches of cut, each tool was studied under a Keyence 3-D microscope in order to quantify the tool wear. High speed, high magnification video was taken of each cut to study all the visible shear angles. The video analysis was completed using KINOVEA video analysis software. The force data was then used to explore different orthogonal metal working models to validate against literature. Statistical analysis was utilized to determine the relationships between visual shear angles and cutting environment. Analysis was made between tool wear and cutting atmosphere.