IE 312 Machining Module ONLINE Lab Week 1 FA22

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Pennsylvania State University *

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312

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Mechanical Engineering

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Dec 6, 2023

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Machining Module – ONLINE Lab Week I Orthogonal cutting is the simplest type of machining process that gives us insight into the mechanics of chip formation during machining operations and allows us to critically examine the influence of machining process variables on machining performance. In machining operations as a cutting tool engages the workpiece, it compresses the material ahead of the advance of the cutting tool causing the material to deform, shear and fracture from the surface of the workpiece. The region ahead of the cutting tool is referred to as the primary shear zone. Severe shearing of the workpiece commonly occurs along a distinct shear plane at a measurable shear angle. Analysis of this region, as well as the resultant chip that moves up the face of the cutting tool can be studied along with the cutting forces to give us insight into the machining process and the machinability of the material being machined. Materials Used: AISI 1018 Steel UTS = 77,000 psi 29% Elongation Hardness = 156 HB Class 30 gray cast iron UTS = 33,000 psi 0% Elongation Hardness = 216 HB 360 brass UTS = 54,700 psi 36% Elongation Hardness = 112 HB Chip Formation Data 0.005 in. depth of cut ( workpiece width 0.125 in., tool rake angle 10 0 , cutting speed 2.5 ipm) Material Shear Angle Chip Thickness Chip Type steel 23 xxx continuous Gray cast iron 51 xxx discontinuous brass 32 xxx segmented 0.002 in. depth of cut ( workpiece width 0.125 in., tool rake angle 10 0, cutting speed 2.5 ipm) Material Shear Angle Chip Thickness Chip Type steel Fig 1 xxx continuous

Gray cast iron Fig 2 xxx discontinuous brass Fig 3 xxx continuous Fig 1 Fig 2 Fig 3 Cutting Force and Chip Formation Data 0.005 in. depth of cut ( workpiece width 0.125 in., tool rake angle 10 0 , cutting speed 2.5 ipm) Material Shear Cutting Thrust

Angle Force (N) Force (N) steel 25 467 200 0.005 in. depth of cut ( workpiece width 0.125 in., tool rake angle -5 0 , cutting speed 2.5 ipm) Material Shear Angle Cutting Force (N) Thrust Force (N) steel 16 676 454 Lab Report (4 pages text, single-spaced + data presentation and interpretation figures and tables) Use the principles described in your textbook (Chapter 21, sections 21.2 and 21.3) to understand and interpret the chip formation lab data. Discuss the influence of the material being machined and depth of cut on the shear angle and the resultant cutting forces. For the cutting force data, estimate the chip thickness and the coefficient of friction at the chip tool interface. How would you expect the values calculated during orthogonal cutting to change if a cutting fluid was used? Explain. What are the practical limits to the maximum depth of cut that can be used for a machining operation? Explain how grinding processes are similar and different from machining processes from the perspective of tool engagement and chip formation. Why is the use of a cutting fluid particularly important during grinding?

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