1 Lathe Machine Introduction Milling Machine Shaper 1 Drilling Machine Metal Cutting A. Rizwan ME – 143 WORKSHOP PRACTICE II SPRING 2010 Lecture 1: Introduction Instructor Asst. Prof. Rizwan Arshad Department of Mechanical & Aerospace Engineering Institute of Avionics & Aeronautics (IAA) AIR University, E-9 Islamabad ME 143 - WORKSHOP TECHNOLOGY Lathe Machine Milling Machine Shaper 2 Drilling Machine Metal Cutting A. Rizwan Introduction • Metal cutting operations are carried out in a machine shop using machine tools • Leading manufacturing industries (aerospace, automobiles etc) use state of the art machine tools to manufacture their products • A machine tool is a metal cutting machine. Conventional machine tools are, • Lathe machine • Shaper • Planer • Slotter • Drill press • Milling machine • Grinding machine etc. Introduction [A typical machine shop]
Lecture 1 - Intro to Single Point Cutting Tool Geometry
Sep 23, 2014
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1
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
1
DrillingMachine
Metal Cutting
A. Rizwan
ME – 143 WORKSHOP PRACTICE IISPRING 2010
Lecture 1: Introduction
Instructor
Asst. Prof. Rizwan Arshad
Department of Mechanical & Aerospace Engineering
Institute of Avionics & Aeronautics (IAA)
AIR University, E-9 Islamabad
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
2
DrillingMachine
Metal Cutting
A. Rizwan
Introduction
• Metal cutting operations are carried out in a machine shopusing machine tools
• Leading manufacturing industries (aerospace, automobiles etc) use state of the art machine tools to manufacture theirproducts
• A machine tool is a metal cutting machine. Conventionalmachine tools are,
• Lathe machine• Shaper• Planer• Slotter• Drill press• Milling machine• Grinding machine etc.
Introduction
[A typical machine shop]
2
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
3
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
• In metal cutting on a machine tool, relative motion b/w cutting tool and job changes the size and shape of the workpiece
• Due to the interaction between workpiece and cutting tool, material is removed in the form of shaving or swarf commonly known as chip
• On the basis of tool orientation, cutting operation can be classified into two
• Orthogonal cutting• Oblique cutting
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
4
DrillingMachine
Metal Cutting
A. Rizwan
[Motions of tool & workpiece]
Metal Cutting
Metal Cutting
3
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
5
DrillingMachine
Metal Cutting
A. Rizwan
[Motions of tool & workpiece]
Metal Cutting
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
6
DrillingMachine
Metal Cutting
A. Rizwan
Metal CuttingMetal Cutting
[Metal cutting operation]
Metal Cutting
4
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
7
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
CUTTING TOOL
• Body having teeth or cutting edges on it
• Single point cutting tool has only one cutting edgee.g. lathe, shaper, planner & boring tool
• Multi-point cutting tool has a number of teeth or cutting edges on its peripherye.g. milling cutter, drill, reamer and broach
[Single point cutting tool] [Multiple point cutting tool. A drill bit]
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
8
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
SINGLE POINT CUTTING TOOL
• A typical geometry of single point cutting tool comprises ofnose, rake face, flank, heel and shank
[Geometry of a single point cutting tool]
Metal Cutting
5
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
9
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TYPES OF SINGLE POINT CUTTING TOOL
• Solid type of single point cutting tool (made of HSS)• Tipped type single point cutting tool (HSS, cemented carbide) • Index able insert type single point cutting tool
[(a) Solid type of single point cutting tool (b) Tipped type single point cutting tool (c) Index able insert type single point cutting tool]
Metal Cutting
(a) (b) (c)
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
10
DrillingMachine
Metal Cutting
A. Rizwan
Metal CuttingNOMENCLATURE – SINGLE POINT CUTTING TOOL
Back rake angle (Positive or Negative)
• Angle between the face of the tool and a line parallel with baseof the tool measured in a perpendicular plane through the sidecutting edge
• Helps to remove chips away from the work piece
Metal Cutting
[Back Rake Angle]Side View
SideView
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ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
11
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
Back rake angle (Positive or Negative)
Metal Cutting
[http://www.mmsonline.com/cdn/cms/Fig.%204%20-%20Chip%20formation.gif]
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
12
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
Side rake angle
• Angle by which the face of tool is inclined side ways. • Provides clearance between work piece and tool so as to
prevent the rubbing of work- piece with end flake of tool
Metal Cutting
[Side Rake Angle]
End View
End View
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ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
13
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
End relief angle
• Angle between the portion of the end flank immediately below the cutting edge and a line perpendicular to the base of the tool, measured at right angles to the flank
• Allows the tool to cut without rubbing on the work- piece
Metal Cutting
[End relief angle]Side View
SideView
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
14
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
Side relief angle
• Angle between the portion of the side flank immediately below the side edge and a line perpendicular to the base of the tool measured at right angles to the side
• Prevents the interference as the tool enters the material
Metal Cutting
[Side Relief Angle]End View
End View
8
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
15
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
End cutting edge angle
• Angle between the end cutting edge and a line perpendicular to the shank of the tool
• Provides clearance between tool cutting edge and work piece
Metal Cutting
Top View Top View
[End Cutting Edge Angle]
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
16
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
Side cutting edge angle
• Angle between straight cutting edge on the side of tool and the side of the shank. It is also known as lead angle
• Responsible for turning the chip away from the finished surface
Metal Cutting
Top View Top View
[Side Cutting Edge Angle]
9
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
17
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
Nose radius• Connects the side cutting edge & end cutting edge • Responsible for generating surface finish on the work-pieceMetal Cutting
Top View Top View
[Nose Radius]
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
18
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
[Elements of tool signature or nomenclature of single point tool]
Metal Cutting
10
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
19
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
NOMENCLATURE – SINGLE POINT CUTTING TOOL
[Elements of tool signature or nomenclature of single point tool]
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
20
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TOOL SIGNATURE – SINGLE POINT CUTTING TOOL
• Angles that a tool utilizes during the cut. It specifies the active angles of the tool normal to the cutting edge
• Valid as long as the tool shank is mounted at right angles to the work-piece axis.
The seven elements that comprise the signature are,
Tool signature 0-7-6-8-15-16-0.81. Back rake angle (0°)2. Side rake angle (7°)3. End relief angle (6°)4. Side relief angle (8°)5. End cutting edge angle (15°)6. Side cutting edge angle (16°)7. Nose radius (0.8 mm)
Metal Cutting
11
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
21
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
MECHANICS
• Workpiece is clamped in machine tool vice• A wedge shaped cutting tool is set to move against the
workpiece with certain depth of cut• By moving the tool against the workpiece, the surface
metal is compressed and split from the workpiece• Unwanted metal is removed by sliding the sheared metal
against the cutting tool• Removed metal takes the form of chips
[Metal cutting operation]
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
22
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
MECHANICS-ORTHOGONAL CUTTING
[Schematic illustration of a two-dimensional cutting process, also called orthogonal cutting]
Metal Cutting
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ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
23
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
MECHANICS-ORTHOGONAL CUTTING
[Forces acting on a cutting tool in two-dimensional cutting. Note that the resultant force, R, must be colinear to balance the forces.]
Metal Cutting
-Cutting force , Fc
-Thrust force , Ft
-Normal force , N
-Friction force , F
-Resultant force , R
-Shear force , Fs, at
the shear plane
-Normal force , Fn,
at the shear plane
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
24
DrillingMachine
Metal Cutting
A. Rizwan
Metal CuttingMECHANICS – OBLIQUE CUTTING
[Schematic illustration of cutting with an oblique tool. (b) Top view showing the inclination angle, i. (c) Types of chips produced with different inclination]
Metal Cutting
13
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Lathe Machine
Introduction
Milling Machine
Shaper
25
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TYPES OF CHIPS
• Continuous• Built up edge• Serrated or segmented • Discontinuous
[Continuous chips, Discontinuous Chips, BUE]
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
26
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TYPES OF CHIPS
Continuous Chip Formation
• Usually formed at high rake angles and/or high cutting speeds• A good surface finish is generally produced• Not always desirable, particularly get tangled around the tool• Need to be remove during the cutting operation
[Continuous Chip Formation Source: After M. C. Shaw, P. K. Wright, and S. Kalpakjian.]
Metal Cutting
14
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
27
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TYPES OF CHIPS
Continuous Chip Formation
[Continuous Chip Formation. Secondary shear zone Source: After M. C. Shaw, P. K. Wright, and S. Kalpakjian.]
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
28
DrillingMachine
Metal Cutting
A. Rizwan
Metal CuttingTYPES OF CHIPS
Built Up Edges (BUE)
• layers of material are deposited over from the workpiece on the tool.
• Unstable and therefore breaks• BUE material is carried away on the tool side of the chip• Rest is deposited randomly on the workpiece surface.• Results in poor surface finish• Reduced by increasing the rake angle & therefore decreasing
the depth of cut
[BUE. Source: After M. C. Shaw, P. K. Wright, and S. Kalpakjian.]
Metal Cutting
15
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
29
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TYPES OF CHIPS
Built Up Edges
[BUE. Source: After M. C. Shaw, P. K. Wright, and S. Kalpakjian.]
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
30
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TYPES OF CHIPS
Segmented or Serrated Chips
• Semi continuous chips with zones of low and high shear strain• Low thermal conductivity and strength metals exhibit this
behavior
[Segmented chips. Source: After M. C. Shaw, P. K. Wright, and S. Kalpakjian.]
Metal Cutting
16
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
31
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TYPES OF CHIPS
Discontinuous
• Discontinuous chips consist of segments that may be firmly orloosely attached to each other
• These chips occur when machining hard brittle materials suchas cast iron.
• Brittle failure takes place along the shear plane before any tangible plastic flow occurs
• Discontinuous chips will form in brittle materials at low rake angles (large depths of cut).
[Discontinuous chips. Source: After M. C. Shaw, P. K. Wright, and S. Kalpakjian.]
Metal Cutting
ME 143 - WORKSHOP TECHNOLOGY
Lathe Machine
Introduction
Milling Machine
Shaper
32
DrillingMachine
Metal Cutting
A. Rizwan
Metal Cutting
TYPES OF CHIPS
Discontinuous
[Discontinuous chips Source: After M. C. Shaw, P. K. Wright, and S. Kalpakjian.]
Metal Cutting
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