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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 1
CHAPTER 8
Material-
Removal
Processes:Cutting
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 2
Cutting Processes
FIGURE 8.1 Examples of cutting processes.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 3
Orthogonal Cutting
FIGURE 8.2 Schematic illustration of a two-dimensional cutting process (also called
orthogonal cutting).
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 4
Chip Formation
FIGURE 8.3 (a) Schematic illustration of the basic mechanism of chip formation in cutting.(b) Velocity diagram in the cutting zone.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 5
Chips Produced in Metal Cutting
FIGURE 8.4 Basic typesof chips produced in metal
cutting and theirmicrographs: (a)continuous chip withnarrow, straight primaryshear zone; (b) secondaryshear zone at the tool-chipinterface; (c) continuous
chip with built-up edge; (d)continuous chip with largeprimary shear zone; (e)segmented ornonhomogeneous chip; and(f) discontinuous chip.Source: After M. C. Shaw,
P. K. Wright, and S.Kalpakjian.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 6
Continuous Chip Formation
FIGURE 8.5 Shiny (burnished) surface on the tool side of a continuous chip produced in
turning.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 7
Chips Produced In Turning
FIGURE 8.8 Various chips produced in turning: (a) tightly curled chip; (b) chip hitsworkpiece and breaks; (c) continuous chip moving away from workpiece; and (d) chip hitstool shank and breaks off. Source: G. Boothroyd,Fundamentals of Metal Machining and
Machine Tools.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 8
Oblique Cutting
FIGURE 8.9 (a) Schematic illustration of cutting with an oblique tool. (b) Top view,showing the inclination angle i. (c) Types of chips produced with different inclination
angles.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 9
Right-Hand Cutting Tool
FIGURE 8.10 (a) Schematic illustration of a right-hand cutting tool. Although these toolshave traditionally been produced from solid tool-steel bars, they have been largely replacedby carbide or other inserts of various shapes and sizes, as shown in (b).
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 10
Terminology in Lathe Turning
FIGURE 8.19
Terminology used in a
turning operation on a
lathe, where f is the feed
(in./rev or mm/rev) and d
is the depth of cut. Note
that feed in turning is
equivalent to the depth of
cut in orthogonal cutting(Fig. 8.2), and the depth
of cut in turning is
equivalent to the turning
is equivalent to the width
of cut in orthogonal
cutting. See also Fig. 8.42.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 11
Types of Cutting Tool
Wear
FIGURE 8.20 (a) Types of wear
observed in cutting tools. The thermal
cracks shown are usually observed in
interrupted cutting operations, such as in
milling. (b) Catastrophic failure of tools.
(c) Features of tool wear in a turning
operation. The VB indicates average
flank wear. Source: (a) and (b) After V.
C. Venkatesh. (c) International
Organization for Standardization (ISO).
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 12
Crater and Flank Wear on a Tool
FIGURE 8.21 (a) Crater wear and (b) flank wear on a carbide tool.Source: J. C, Keefe,
Lehigh University.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 13
Range of
Surface
Rough-nesses
FIGURE 8.27Range of surfaceroughnessesobtained in variousmachiningprocesses. Note thewide range withineach group. (Seealso Fig. 9.27).
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 14
Carbide InsertsFIGURE 8.32 (a) Typicalcarbide inserts with various
shapes and chip-breakerfeatures. Round inserts arealso available. The holes inthe inserts are standardizedfor interchangeability.Source: Courtesy ofKyocera EngineeredCeramics, Inc., and
ManufacturingEngineering, Society ofManufacturing Engineers.(b) Methods of attachinginserts to a tool shank byclamping, (c) with winglockpins, and (d) with a
brazed insert on a shank.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 15
Relative
Edge
Strength
FIGURE 8.33 Relative edge strength and tendency for chipping and breaking of insertswith various shapes. Strength refers to that of the cutting edge shown by the included angles.Source: Kennametal, Inc.
FIGURE 8.34 Edge preparation of
inserts to improve edge strength.
Source: Kennametal, Inc.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 16
Properties of Tool Materials
FIGURE 8.38 Ranges of properties for various groups of tool materials. (See also various
tables in this chapter.)
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 17
Construction of Insert
FIGURE 8.39 Construction of polycrystalline cubic-boron-nitride or diamond layer on atungsten-carbide insert.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 18
Machining
Processes
TABLE 8.7 Generalcharacteristics of machining
processes.
Process Characteristics Commercial tolerances(mm)
Turning Turning and facing operations on all types ofmaterials; requires skilled labor; low production rate,but medium to high with turret lathes and automaticmachines, requiring less-skilled labor.
Fine: 0.05-0.13Rough: 0.13Skiving: 0.025-0.05
Boring Internal surfaces or profiles, with characteristicssimil ar to turning; stif fness of boring bar important toavoid chatter.
0.025
Drilling Round holes of various sizes and depths; requiresboring and reaming for improved accuracy; highproduction rate; labor skill required depends on holelocation and accuracy specified.
0.075
Mill ing Variety of shapes involving contours, flat surfaces,and slots; wide variety of tooling; versatile; low tomedium production rate; requires skill ed labor.
0.13-0.25
Planing Flat surfaces and straight contour profiles on largesurfaces; suitable for low-quantity production; laborskill required depends on part shape.
0.08-0.13
Shaping Flat surfaces and straight contour profiles on relativelysmal l workpieces; suitable for low-quantity production;labor skill required depends on part shape.
0.05-0.13
Broaching External and internal flat surfaces, slots and contourswith good surface f inish; costly tooling; highproduction rate; labor skill required depends on partshape.
0.025-0.15
Sawing Straight and contour cuts on flats or structural shapes;
not suitable for hard materials unless saw has carbideteeth or is coated with diamond; low production rate;requires only low labor skill.
0.8
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 19
Lathe
Operations
FIGURE 8.40 Variouscutting operations that canbe performed on a lathe.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 20
Designations for a Right-
Handed Cutting Tool
FIGURE 8.41 (a) Designations and symbols for aright-hand cutting tool; solid high-speed-steeltools have a similar designation. The designationright hand means that the tool travels from rightto left, as shown in Fig. 8.19 (b) Square insert in aright-hand toolholder for a turning operation. Awide variety of toolholder is available for holdinginserts at various angles. Thus, the angles shownin (a) can be achieved easily by selecting anappropriate insert and toolholder. Source:Kennametal, Inc.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 21
Turning Operation
FIGURE 8.42 (a) Schematic illustration of a turning operation showing depth of cut,d, andfeed,f. cutting speed is the surface speed of the workpiece at the tool tip. (b) Forces actingon a cutting tool in turning.Fcis the cutting force;Ftis the thrust or feed force (in thedirection of feed); andFris the radial force that tends to push the tool away from the
workpiece being machined. Compare this figure with Fig. 8.11 for a two-dimensionalcutting operation.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 22
Range of Cutting Speeds
FIGURE 8.43 The range of applicable cutting speeds and fees for a variety of tool
materials. Source: Valenite, Inc.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 23
Cutting Speeds in Turning
TABLE 8.8 Approximate range of recommended cutting speeds for turning operations.
CUTT ING SPEEDWORKPIECE MATERIAL
m/min ft/min
Aluminum alloys
Cast iron, grayCopper alloys
High-temperature alloysSteels
Stainless steelsThermoplastics and thermosets
Titanium alloys
Tungsten alloys
200-1000
60-90050-700
20-40050-500
50-30090-240
10-100
60-150
650-3300
200-3000160-2300
65-1300160-1600
160-1000300-800
30-330
200-500
Note:(a) These speeds are for carbides and ceramic cutting tools. Speeds for high-speed steel
tool are lower than indicated. The higher ranges are for coated carbides and cermets. Speeds fordiamond tools are significantly higher than those indicated.
(b) Depths of cut, d, are generally in the range of 0.5-12 mm (0.02-0.5 in.)(c) Feeds, f, are generally in the range of 0.15-1 mm/rev (0.006-0.040 in./rev).
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
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Components of a Lathe
FIGURE 8.44 Schematic illustration of the components of a lathe.Source: Courtesy of
Heidenreich & Harbeck.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
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Machine Tool Parts Example
FIGURE 8.46 Typical parts made on computer-numerical-control machine tools.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 26
Chisel and Crankshaft-Point Drills
FIGURE 8.48 (a) Standard chisel-point drill, with various features indicated. (b)
Crankshaft-point drill.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 27
Drills and Drilling Operations
FIGURE 8.49 Various types of drills and drilling operations.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 28
Speeds and Feeds in Drilling
TABLE 8.10 General recommendations for speeds and feeds in drilling.
SURFACE
SPEED
FEED, mm/rev (in./rev)
DRILL DIAMET ER
RPMWORKPIECE
MATERIALm/min ft/min 1.5 mm
(0.060 in.)12.5 mm(0.5 in.)
1.5 mm 12.5 mm
Aluminum alloysMagnesium alloysCopper alloysSteelsStainless steels
Titanium alloysCast ironsThermoplasticsThermosets
30-12045-12015-6020-3010-20
6-2020-6030-6020-60
100-400150-40050-20060-10040-60
20-6060-200
100-20060-200
0.025 (0.001)0.025 (0.001)0.025 (0.001)0.025 (0.001)0.025 (0.001)
0.010 (0.0004)0.025 (0.001)0.025 (0.001)0.025 (0.001)
0.30 (0.012)0.30 (0.012)0.25 (0.010)0.30 (0.012)0.18 (0.007)
0.15 (0.006)0.30 (0.012)0.13 (0.005)0.10 (0.004)
6400-25,0009600-25,0003200-12,0004300-64002100-4300
1300-43004300-12,0006400-12,0004300-12,000
800-30001100-3000400-1500500-800250-500
150-500500-1500800-1500500-1500
Note:As hole depth increases, speeds and feeds should be reduced. Selection of speeds andfeeds also depends on the specific surface finish required.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
Prentice Hall, 2003 page 29
Reamer and Tap Terminology
FIGURE 8.50 Terminology for a helical reamer.
FIGURE 8.51 Terminology for a tap.
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Manufacturing Processes for Engineering Materials, 4th ed.
Kalpakjian Schmid
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Milling Operations
FIGURE 8.53 (a) Schematic illustration of conventional milling and climb milling. (b)Slab-milling operation, showing depth of cut, d; feed per tooth,f; chip depth of cut, tc; andworkpiece speed, v. (c) Schematic illustration of cutter travel distance to reach full depth ofcut.