Design for Machining: Selection of Manufacturing Processes Notes | EduRev

: Design for Machining: Selection of Manufacturing Processes Notes | EduRev

 Page 1


 
 
 
 
 
 
 
 
 
 
 
 
Module 
3 
Selection of Manufacturing 
Processes 
Page 2


 
 
 
 
 
 
 
 
 
 
 
 
Module 
3 
Selection of Manufacturing 
Processes 
 
 
 
 
 
 
 
 
 
 
 
 
 
Lecture 
5 
Design for Machining 
Page 3


 
 
 
 
 
 
 
 
 
 
 
 
Module 
3 
Selection of Manufacturing 
Processes 
 
 
 
 
 
 
 
 
 
 
 
 
 
Lecture 
5 
Design for Machining 
Instructional objectives 
By the end of this lecture, the student will learn 
(1) what are the different machining processes and their applications, 
(2) advantages, disadvantages and design guidelines of parts for machining, 
(3) concept and definition of machinability, and how to improve the same. 
 
Introduction and Classification 
Machining is the manufacturing process by which parts can be produced to the desired 
dimensions and surface finish from a blank by gradual removal of the excess material in the 
form of chips with the help of a sharp cutting tool. Almost 90% of the all engineering 
components are subjected to some kind of machining during manufacture. It is very important 
to design those parts in such a way that would lead to the increase in efficiency of the 
machining process, enhancement of the tool life and reduction of the overall cost of 
machining. To achieve these targets, a brief knowledge of various machining processes is 
required. Figure 3.5.1 depicts a brief classification of various machining processes that are 
widely used in the manufacturing and fabrication industries of all kinds. 
 
Overview of Major Machining Processes 
Turning 
Turning is the most important machining process and can produce a wide variety of parts. 
Primarily, turning is used to produce parts cylindrical in shape by a single point cutting tool 
on lathes. The cutting tool is fed either linearly in the direction parallel or perpendicular to 
the axis of rotation of the workpiece, or along a specified path to produce complex rotational 
shapes. The primary motion of cutting in turning is the rotation of the workpiece, and the 
secondary motion of cutting is the feed motion. Figure 3.5.2 depicts a typical turning 
operation in lathes. Different types of lathes are available today from general purpose to 
specific job oriented special purpose machines. In general, turning refers to a class of 
processes carried out on a lathe. A brief outline of some the sub-class of turning processes 
are presented below.  
 
 
 
Page 4


 
 
 
 
 
 
 
 
 
 
 
 
Module 
3 
Selection of Manufacturing 
Processes 
 
 
 
 
 
 
 
 
 
 
 
 
 
Lecture 
5 
Design for Machining 
Instructional objectives 
By the end of this lecture, the student will learn 
(1) what are the different machining processes and their applications, 
(2) advantages, disadvantages and design guidelines of parts for machining, 
(3) concept and definition of machinability, and how to improve the same. 
 
Introduction and Classification 
Machining is the manufacturing process by which parts can be produced to the desired 
dimensions and surface finish from a blank by gradual removal of the excess material in the 
form of chips with the help of a sharp cutting tool. Almost 90% of the all engineering 
components are subjected to some kind of machining during manufacture. It is very important 
to design those parts in such a way that would lead to the increase in efficiency of the 
machining process, enhancement of the tool life and reduction of the overall cost of 
machining. To achieve these targets, a brief knowledge of various machining processes is 
required. Figure 3.5.1 depicts a brief classification of various machining processes that are 
widely used in the manufacturing and fabrication industries of all kinds. 
 
Overview of Major Machining Processes 
Turning 
Turning is the most important machining process and can produce a wide variety of parts. 
Primarily, turning is used to produce parts cylindrical in shape by a single point cutting tool 
on lathes. The cutting tool is fed either linearly in the direction parallel or perpendicular to 
the axis of rotation of the workpiece, or along a specified path to produce complex rotational 
shapes. The primary motion of cutting in turning is the rotation of the workpiece, and the 
secondary motion of cutting is the feed motion. Figure 3.5.2 depicts a typical turning 
operation in lathes. Different types of lathes are available today from general purpose to 
specific job oriented special purpose machines. In general, turning refers to a class of 
processes carried out on a lathe. A brief outline of some the sub-class of turning processes 
are presented below.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.5.1 Classification of Machining Processes [5] 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.5.2 Schematic depiction of turning operation [4] 
 
Straight turning is used to reduce the diameter of a part to a desired dimension (Figure 
3.5.3a). The resulting machined surface is cylindrical. Contour turning and Taper turning 
(Figure 3.5.3b) are performed by employing a complex feed motion using special 
attachments to a single point turning tool thus creating a contoured shape on the workpiece. 
Turning 
Milling  
Drilling 
Planing 
Shaping 
Broaching 
Gear cutting 
Boring 
 
Polishing 
Buffing 
Lapping 
Grinding 
Honing 
Superfinishing 
Abrasive jet machining 
Ultrasonic machining 
Water jet machining 
Magnetic abrasive 
finishing 
Electro chemical machining 
Electro Discharge machining 
Laser beam machining 
Plasma beam machining 
Page 5


 
 
 
 
 
 
 
 
 
 
 
 
Module 
3 
Selection of Manufacturing 
Processes 
 
 
 
 
 
 
 
 
 
 
 
 
 
Lecture 
5 
Design for Machining 
Instructional objectives 
By the end of this lecture, the student will learn 
(1) what are the different machining processes and their applications, 
(2) advantages, disadvantages and design guidelines of parts for machining, 
(3) concept and definition of machinability, and how to improve the same. 
 
Introduction and Classification 
Machining is the manufacturing process by which parts can be produced to the desired 
dimensions and surface finish from a blank by gradual removal of the excess material in the 
form of chips with the help of a sharp cutting tool. Almost 90% of the all engineering 
components are subjected to some kind of machining during manufacture. It is very important 
to design those parts in such a way that would lead to the increase in efficiency of the 
machining process, enhancement of the tool life and reduction of the overall cost of 
machining. To achieve these targets, a brief knowledge of various machining processes is 
required. Figure 3.5.1 depicts a brief classification of various machining processes that are 
widely used in the manufacturing and fabrication industries of all kinds. 
 
Overview of Major Machining Processes 
Turning 
Turning is the most important machining process and can produce a wide variety of parts. 
Primarily, turning is used to produce parts cylindrical in shape by a single point cutting tool 
on lathes. The cutting tool is fed either linearly in the direction parallel or perpendicular to 
the axis of rotation of the workpiece, or along a specified path to produce complex rotational 
shapes. The primary motion of cutting in turning is the rotation of the workpiece, and the 
secondary motion of cutting is the feed motion. Figure 3.5.2 depicts a typical turning 
operation in lathes. Different types of lathes are available today from general purpose to 
specific job oriented special purpose machines. In general, turning refers to a class of 
processes carried out on a lathe. A brief outline of some the sub-class of turning processes 
are presented below.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.5.1 Classification of Machining Processes [5] 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.5.2 Schematic depiction of turning operation [4] 
 
Straight turning is used to reduce the diameter of a part to a desired dimension (Figure 
3.5.3a). The resulting machined surface is cylindrical. Contour turning and Taper turning 
(Figure 3.5.3b) are performed by employing a complex feed motion using special 
attachments to a single point turning tool thus creating a contoured shape on the workpiece. 
Turning 
Milling  
Drilling 
Planing 
Shaping 
Broaching 
Gear cutting 
Boring 
 
Polishing 
Buffing 
Lapping 
Grinding 
Honing 
Superfinishing 
Abrasive jet machining 
Ultrasonic machining 
Water jet machining 
Magnetic abrasive 
finishing 
Electro chemical machining 
Electro Discharge machining 
Laser beam machining 
Plasma beam machining 
Facing (Figure 3.5.3c) is done to create a smooth, flat face perpendicular to the axis of a 
cylindrical part. The tool is fed radially or axially to create a flat machined surface. Thread 
cutting (Figure 3.5.3d) is possible in lathe by advancing the cutting tool at a feed exactly 
equal to the thread pitch. The single-point cutting tool cuts in a helical band, which is 
actually a thread. The tool point must be ground so that it has the same profile as the thread to 
be cut. Thread can be both external and internal types. In form turning (Figure 3.5.3e), the 
shape of the cutting tool is imparted to the workpiece by plunging the tool into the workpiece. 
In form turning, the cutting tool can be very complex and expensive but the feed will remain 
linear and will not require special machine tools or devices. Boring (Figure 3.5.3f) is similar 
to straight turning operation but differs in the fact that it can produce internal surface of 
revolution, which is often considered to be difficult due to overhanging condition of the tool. 
 
(a) (b) (c) 
(d) (e) (f) 
Figure 3.5.3 Different types of Turning Operations [5] 
 
Milling 
Milling is a process of producing flat and complex shapes with the use of multi-point (or 
multi-tooth) cutting tool. The axis of rotation of the cutting tool is perpendicular to the 
direction of feed, either parallel or perpendicular to the machined surface. Milling is usually 
an interrupted cutting operation since the teeth of the milling cutter enter and exit the 
workpiece during each revolution. This interrupted cutting action subjects the teeth to a cycle 
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