This document discusses various topics related to turning machines and lathes. It begins by listing the topics to be discussed, which include the construction, operations, and attachments of center lathes. It then describes the main parts of a lathe such as the bed, headstock, tailstock, and carriage. The document outlines the specifications used for lathes and lists different types. It provides details on lathe operations including taper turning methods, thread cutting, and attachments. The document also covers topics like cutting speed, feed rate, material removal rate, and power estimation for lathe operations.
3. Topics to be Discussed
▰ Construction, specification and operations of Centre lathes
▰ Taper turning methods, Thread cutting methods and Special
attachments
▰ Machining time and power estimation.
▰ Capstan and turret lathes
▰ Tool layout
▰ Automatic lathes
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10. Specification of a Lathe
▰ The length of bed
▰ Type of bed
▰ Swing over the bed
▰ Swing over the cross slide
▰ Width of the bed
▰ Spindle bore
▰ Spindle speed
▰ HP of main motor and rpm
▰ Spindle nose diameter
▰ Feeds
▰ Floor space required
▰ Maximum distance between dead and live centres
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It is the volume of material removed per unit time.
Volume of material removed in one revolution = πDi x d x f mm3
MRR = πDi x d x f x N mm3/min
MRR = 1000 x V x d x f mm3/min
Di = initial diametre of the workpiece,mm
d = depth of cut,mm
f = feed,mm/revolution
Material Removal Rate (MMR)
Example Problem: 23.1 (Page No. 636) in Manufacturing
Engineering and Technology by Kalpakjian (Pearson, 7th Edition)
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Estimation of Power
Power (P) = Cutting Force (Fc) x Cutting Speed (V)
Cutting Force (Fc) = K x d x f
Where, K = Constant depending of workpiece
P = K x d x f x V
Problem: A blank 180mm long and 70mm diameter is to be machined in a lathe to
175mm long and 60mm diameter. The workpiece rotates at 450rpm, the feed is
0.3mm/rev and the max depth of cut is 2mm. For turning operation; the approach plus
over travel diatance is 6mm. Assuming that the facing operation is done after the
turining. Calculate the machining time. [AU - Apr/May 12].
60. Tool Layout
▰ Selection of tools
▰ Designing of special tools
▰ Selection of speed
▰ Selection of feed
▰ Setting required length of
workpiece and tool travel
length.
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