Ch 21
Sawing
A basic machining process in which chips are produced by a succession of small cutting edges, or teeth, arranged in a narrow line on a saw "blade".
Machine Tool
A stationary, power-driven machine used to cut, shape, or form materials such as metal and wood.
Built Up Edge
A variation of continuous chip, often encountered in machining ductile materials.
Shear force
Aka flow stress-is a material constant.
Shear velocity
Can be found using sophisticated electronics and slow-motion playback.
Cutting Velocity
Can cause the process-induced variation in the cutting force.
Regenerative chatter
Caused by a phase shift between overlapping cutting paths ;a self-excited vibration that is caused by the closed -loop displacement response of the machining process
Shear strain
Depends only on the rake angle (alpha) ; expressed as cosine of alpha divided by one plus the sine of alpha.
Work piece
Held in work holding devices.
Work holding device
Holds work pieces.
Feed
Is the amount of material removed per revolution per per pass of the tool over the workpiece.
Grinding
One of the 7 basic chip formation processes. (Discussed in chapters 23-27).
Drilling
One of the 7 basic chip formation processes. A rotational multiple-edge tool process.
Broaching
One of the seven basic machining processes in chip formation. Broach, cutting tool moves into work, and work stationary are the machine areas.
Speed
Primary cutting motion, which relates the velocity of the cutting tool relative to the work piece.
Stability lobe diagram
Relates the total width of cut that can be machined to the rotational speed of the tool with a specified number of cutting edges.
Back Rake Angle
The angle that the tool makes with respect to a vertical from the workpiece.
Chip Velocity
The chip has a velocity V_c. (NOTE: look at figure 21-17 page 498)
Depth of Cut
The distance the tool is plunged into the surface.
Vibration
The mechanism by which a process dissipates energy.
Chatter
The most common metal cutting example due to the regeneration of surface waving. Part of self-excited vibration in machining.
Shear angles
The onset of the shear process takes place along the lower boundary of the shear zone defined by the shear angle (phi)
Self-excited vibration
The periodic response of the system to a constant input
Milling
The process of ____ requires two figures because it takes different forms depending upon the selection of the machine tool and the cutting tool; a multiple tooth process, has two feeds; has replaced shaping and planning
Turning
The process of machining external cylindrical and conical surfaces.
Metal Cutting
The process of removing unwanted material from a metal workpiece in the form of chips (often called metal removal).
Dynamics
The product of static stiffening and dampening.
Shaping
The work piece is fed at right angles to the cutting motion between successive strokes of the tool
Oblique machining
Three-dimensional geometry; the cutting edge and the cutting motion are not perpendicular to each other
Orthogonal machining
Two dimensional geometry; done to test machining mechanics and theory; the cutting velocity vector and the cutting edges are perpendicular.
Cutting Stiffness
Used interchangeably with the term specific energy U. A material property related to shear flow stress, hardness and work hardening and is often described in a relative sense of the machinability of materials.
Chip Ratio
Used to compute the shear angle. Defined as t/t_c.
Cutting Tool
Used to machine the workpiece and is the most critical component.
Specific horsepower
Values found experimentally using orthogonal machining
Friction Force
What the resultant R is composed of along with the normal force N acting on the tool/chip interface contact area.
Boring
Where a reduced lead angle or a less round (and smaller nose radius compared to DOC) inserts maintains more axial (stiffer tool direction) orientation of Y, leading to greater stability.