What Is Cutting? 120

This class addresses the theory of proper chip formation during the machining process. Includes an Interactive Lab.

Class Details

Class Name:
What Is Cutting? 120
This class addresses the theory of proper chip formation during the machining process. Includes an Interactive Lab.
Number of Lessons:
Additional Language:
Spanish, Chinese
Related 2.0 Classes:
Cutting Processes 111, Basic Cutting Theory 201

Class Outline

  • Objectives
  • What Is Cutting?
  • Cutting Tools
  • What Is a Chip?
  • The Making of a Chip
  • Cutting Angles
  • Continuous and Discontinuous Chips
  • Built-up Edge
  • Chip Control
  • Cutting Variables for Turning
  • Cutting Variables for Drilling
  • Cutting Variables for Milling
  • The Importance of Cutting Conditions
  • Summary


  • Define cutting.
  • Describe single- and multi-point cutting tools.
  • Identify which cutting operations make chips.
  • Describe how a chip is made.
  • Describe the significance of cutting angles.
  • Describe continuous and discontinuous chips.
  • Describe a built-up edge.
  • Describe methods of chip control.
  • Define cutting variables for turning.
  • Define cutting variables for drilling.
  • Define cutting variables for milling.
  • Describe the importance of cutting conditions.


  • MSSC Manufacturing Processes and Production


Vocabulary Term Definition
axis The imaginary line around which a part rotates as it is turned.
brittle Difficult to bend, stretch, or form without breaking. Brittle metals tend to produce discontinuous chips.
built-up edge Deformed metal that adheres to the cutting edge of the tool under high pressures and temperatures.
carbide A common cutting tool material that is used to make both indexable inserts and solid cutting tools. They provide a cutting edge that is very hard and wear resistant.
casting A metal part that is formed by pouring molten metal into a mold. The metal then cools and solidifies into its final shape.
chip An unwanted piece of metal that is removed from a workpiece. Chips are formed when a tool cuts or grinds metal.
chip breaker A device located on the cutting tool or toolholder that is designed to prevent chips from forming into long pieces.
continuous chip A chip that does not break apart and instead continues to fold in on itself. Ductile metals tend to create continuous chips.
crystalline structure The arrangement or pattern of molecules in a metal. Each metal has a specific crystalline structure that determines its unique properties.
cutting The use of single- or multi- point tools to separate metal from a workpiece in the form of chips.
deform The forming of a metal into a distorted shape. Deformed metal has permanently lost its original shape.
depth of cut The distance that the cutting tool is plunged into the workpiece. Depth of cut is typically measured in millimeters or inches.
discontinuous chip A chip that easily fractures from the workpiece into small, separate pieces. Brittle materials tend to create discontinuous chips.
drill press A machine tool that rotates a cutting tool with enough force to cause it to penetrate the surface of the workpiece and make a round hole to a certain depth.
drilling The use of a multi-point tool to machine a new round hole into the surface of a workpiece.
ductile Able to bend, stretch, or form without breaking. Ductile metals tend to produce long, continuous chips.
end mill A thin, tall mill cutter with cutting edges that wind up the sides. Both the bottom and side of the end mill are used during milling operations. End mills resemble drills.
face mill A flat mill cutter with multiple cutting teeth surrounding the tool. The bottom of the face mill is primarily used during milling operations.
feed The rate at which the cutting tool and the workpiece move in relation to one another.
fixture A customized workholding tool used on machine tools to position and hold a part during various machining operations.
flute The spiral grooves in a tool that create a path for the removal of chips during cutting.
forging A metal working process that involves forming or shaping bulk metal into parts at elevated temperatures.
insert A cutting bit that has multiple cutting edges. Once a cutting edge is excessively worn, it can be indexed to another edge, or the insert can be replaced.
lathe A machine tool that holds a cylindrical workpiece at one or both ends and rotates it while various cutting tools remove material. Turning is a common operation performed on the lathe.
machining The process of removing metal to form or finish a part, either with traditional methods like turning, drilling, milling, and grinding, or with less traditional methods that use electricity, heat, or chemical reaction.
metal working A material manufacturing process that produces parts by mechanically deforming metal into parts. Stamping and forging are two major types of metal working processes.
milling The use of a rotating multi-point cutting tool to machine flat surfaces, slots, or internal recesses into a workpiece. Milling includes a wide range of versatile metal cutting operations.
milling machine A machine tool used to perform milling and various other cutting operations. Milling machines are most often used to produce flat or rectangular workpieces.
multi-point cutting tool A machining tool that has two or more cutting edges.
rake angle The angle that the front of the cutting tool is tilted either forward or backward from its perpendicular position.
relief angle The angle that is formed by the surface of the workpiece and the bottom end of the cutting tool.
shear force A force that attempts to cause the internal structure of a material to slide against itself.
shear strain The deformation that occurs due to forces that attempt to cause the internal structure of a material to slide against itself.
single-point cutting tool A machining tool that has one single cutting edge.
speed The rate that the cutting tool or workpiece moves at the point of contact.
stamping A metal working process that involves forming or separating sheet metal into parts with the use of dies and punches.
tool chatter The development of surface imperfections on the workpiece caused by vibrations of the cutting tool.
tool life The length of time that a cutting tool can function properly before it begins to fail.
turning The machining process used to make cylindrical parts. Turning is commonly performed with a lathe.