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Ernesto Gutierrez-Miravete
UNAM, March 2007
Mathematical Modeling of
Metal Machining Processes
Part I
A Common and Flexible Materials Processing
Operation used to produce Shaped Metal
Artifacts from a Bulk Work Piece.
The Operation consists of the Gradual and
Controlled Removal of Thin Layers of
Material from the surface of the Work by a
Special Cutting Process.
The Special Cutting Process consists of a
Hard Tool with a Large-Angled Wedge which
is driven Asymmetrically into the Work.
Definition of Metal Machining
• Starts in large scale as Machines and
Carbon Steel Tools are developed around
1800, to fulfill the needs of the Industrial
• Significant Increase in Efficiency around
1900 with the development of High Speed
Steel Tools and Management Science.
• Further enhancements during the XX
century due to New Tool Materials and
Advances in Machine Tools, Manufacturing
Engineering and Computers.
A Short History of Metal Machining
Very small tolerances possible
Very high surface finish quality possible
Very complex parts possible
Very large parts possible
Effectively incorporation and leveraging of
advances in machine tool technology,
manufacturing systems engineering and
materials technology for increased
process efficiency and productivity.
Attractive Features of
Metal Machining Processing
• Part Production with the Highest Possible
• Part Production at the Fastest Possible
• Part Production with the Lowest Possible
• Part Production with the Greatest Possible
Keys to Success in
Machining Processing
Factors in Machinability
Common Machining Materials
Recommended Tool Materials
• Detailed Specification of the Finished Part
Geometry (CAD)
• Detailed Specification of Tooling and Tool
Path Motions Required (CAM)
• Actual Machining (CNC)
• Finished Part Quality Check (Metrology)
Steps in Producing a
Modern Machined Part
A Modern Machined Component
(Intermediate Stage of Machining)
A Modern Machined Component
(Intermediate Stage of Machining)
Milling and Drilling
End Milling
Metallographic Methods in Metal
Machining Research
Chip Formation
Quick Stop Test
Quick Stop
Spheroidized Steel (Trent)
Chip Microhardness-316 Steel
Chip Shapes
Chip Metallography
Low Carbon Steel (Trent)
Chip Metallography (detail)
Secondary Shear Zone
Chip Engraving (Zorev)
Chip Engraving
Low Carbon Steel (Oxley)
Chip Time Lapse Photography
Chip Time Lapse Photo (contd.)
Chip Engraving with BUE
Undeformed and Deformed Chip
Primary and Secondary Shear
Zones in Cutting
Secondary Shear Zone Strain
Worn Tool Macrograph (Trent)
Pressure on Tool
Worn Tool Microhardness and
Cutting Temperature (Trent)
Cutting Tool Wear
Measurement of Cutting Forces
Measured Cutting Forces
Pure Metals
Calculated Flow Stress and
Temperature - Pure Metals
Measured Cutting Forces
Measured Cutting Forces
Copper Alloys
Measured Cutting Forces
Measured Cutting Forces
Fe, Ni and Ti Alloys
Calculated Flow Stress and
Temperature – Fe, Ni, Ti Alloys
Measured Cutting Forces
C and Alloys Steels
Calculated Flow Stress and
Temperature – C and Alloys Steels
Measurement of Cutting Temperature
Direct Thermocouple Method
Measured Cutting Temperatures
Measurement of Cutting Temperature
Embedded Thermocouple Method
Measured Tool Temperatures
WC Insert
Measurement of Cutting Temperature
Optical Pyrometer Method
Measured Tool Temperatures
WC Insert
• Machining is an Attractive and Useful Metal
Shaping Process.
• Much Machining Know-How to Date has been
obtained by purely Empirical Methods inside
actual Machine Shops for over 200 years.
• Much New Knowledge about the Physics of
Metal Chip Formation has been obtained by
direct Application of Standard Metallographic
Examination Techniques.
• Much Additional Useful New Insight about
Machining has been obtained from Experimental
Measurement of Cutting Forces and
• D.A. Stephenson and J.S. Agapiou, Metal Cutting
Theory and Practice, CRC, Boca Raton, 2006.
• M.C. Shaw, Metal Cutting Principles, 2nd ed. Oxford UP,
New York, 2005.
• E.M. Trent and P.K. Wright, Metal Cutting, 4th ed.
Butterworth-Heinemann, Boston, 2000.
• T.H.C. Childs et al. Metal Machining: Theory and
Applications, Arnold, London, 2000.
• Y. Altintas, Manufacturing Automation: Metal Cutting
Mechanics, Machine Tool Vibrations and CNC Design,
Cambridge UP, Cambridge, 2000.
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