Centre lathe, constructional features, various operations and specifications, taper turning methods, thread cutting methods, special attachments, machining time and power estimation. Capstan and turret lathes – Automatic lathe: single spindle, swiss type, screw type, multi spindle - Turret Indexing mechanism - Bar feed mechanism
2. CUTTING TOOLS
• SINGLE POINT CUTTING TOOL
Its used for turning, facing , chamfering,
thread cutting and parting off operations
• MULTI POINT CUTTING TOOL
Its used for knurling, drilling and milling
operations
3. CLASSIFICATION OF CUTTING TOOLS
1.According to the manufacturing of cutting tool
a. Forged tool
b. Tipped tool brazed to the carbon steel shank
c. Tipped tool fastened mechanically to the
carbon steel shank
2. According to the method of holding the tool
a. Solid tool
b. Tool bit inserted in the tool holder
4. .
3.According to the method of using the tool
a. Turning
b. Chamfering
c. Thread cutting
d. Facing
e. Forming
f. Boring
g. Internal Thread Cutting
h. Grooving
i. Parting off
4. According to the method of applying feed
a. Right hand tool
b. Left hand tool
c. Round nose tool
5. 1.According to the method of manufacturing the tool
1. Forged tool – heating - hammering and cooling
2. Brazed tipped tools –
The tool is made up of cemented carbide,
Having high brittleness , strength and also cost
The different form of this tip is placed on the tip of HSS tool
6. Various brazing process
• Torch brazing
To melt the filler rod and to heat the base material
acetylene + natural gas + butane or propane + air are used to heat
Its used for mass production
7. Furnace Brazing
A electric heating coil or gas is
used to supply heat
The tip to be joined is placed
correctly on the base metal.
Due to heat the tip is joined
with base material
8. High frequency induction Brazing
The electric and magnetic
resistance of the changing
induction field are used to
produce the eddy current
The eddy current is used to heat
the metal to be joined
9. Dip Brazing
a. Chemical dip brazing
The parts to be joined is placed correctly and dipped in
the chemical solution
Its used for joining large parts
b. Molten metal bath
The parts to be joined is first pre fluxed and then
immersed in to the molten filler metal
Its used for joining smaller parts
10. Resistance Brazing
• Rapid heating on a spot by electric resistance used to
join the filler metal correctly on the base metal
11. Laser Brazing and electron beam
Brazing
• From the use of laser and electron beam the
heat is produced to join the filler metal with
base metal.
• It’s a costly process
• Only used for high precision work.
13. 2. According to the method of holding the tool
1. Solid Tool
Without any other process these tools are forged or ground to require
shape for direct use in lathe.
2. Tool bit Inserted in the tool Holder
A bit of require form of tool can be
Inserted by clamps.
It’s a cheapest method
We can adjust the cutting height easily
14. 3.According to the method of using the tool
1.Turning tool
a. Rough Turning – For removing more material
b. Finish Turning – For having fine and smooth surface
15. 2. Chamfering Tool
• A specially designed tool with some cutting
angle is used for chamfering operation
16. 3.Shoulder turning tool
• Usually square shoulder is turned by knife edge turning tool
or facing tool.
• But beveled surface are turned by a turning tool having a side
cutting edge and zero nose radius
• A curved shoulders are formed by tool having corresponding
fillet radius
17. 4.Thread cutting – External - Internal
• The single point cutting tool with correct cutting
edge corresponding to the shape and size of the
thread required are chosen to perform external
thread cutting.
• By adjusting the front clearance angles we can
perform the internal cutting on the same tool
18. 5.Facing tool
• In this type the side cutting edge of the tool
remove the metal.
• They give proper rake angles also.
19. 6.Grooving tool
• The tool shape can be made in to square,
round and V according to the shape to be cut
on the metal.
20. 7. Forming Tool
• To produce irregular shape on work piece the
tools are designed to different forms
21. 8.Boring tool
• A cemented carbide tool is attached to the
boring bar.
• This work is done on the already drilled hole
for enlarging the hole size
22. 9. Counter Boring
• This type of tool having multi point cutting
edges.
• This is done for enlarging the particular hole
23. 10. Under cutting tool
• Its a operation to reduce the diameter for a
small portion over the external surface of the
work piece.
• The cutting edge have more clearance angle
than the width of the cutting tool edge.
24. 11.Parting off tool
• These are forged type tool
• Cemented carbide tipped tools are used
• The cutting edge is formed into narrow to
remove minimum metal during parting off the
work piece.
• This tool have no side rake with small back
rake.
25. 12.Right – left Hand tools
• Right Hand – the cutting edge is formed on the left hand end
It cut the metal when it move from right to
the left hand end of the lathe bed
• Left Hand - It cut the metal when it move from left to right
hand end of the lathe bed
• Round nose tool – this tool having zero rake and side rake
angles. Perform on both direction
27. 1. Centering
• It’s a operation performed on the work piece
both ends.
• Here we make a conical hole on the work pice
28. Turning
• It’s a operation to
reduce the diameter of
the work piece.
• The job is revolving in
chuck or between
centers.
• The right or left hand
tool will perform the
operation
29. Facing
• Facing is the operation
to reduce length of the
work piece
• Here the tool moves
perpendicular to the
lathe axis
30. Chamfering & Knurling
• Chamfering is the process of beveling the
work piece edges. Some times for removing
burrs and sharpness
• Knurling is the process of making impressions
on the surface of the work piece by a special
multi point tool
31. Forming
• It’s a process of making
concave or convex or any
irregular shape on the work
piece by a form tool
32. Grooving
• It’s a process of reducing
diameter of the work
piece
• its also called recessing,
undercutting or necking
34. Eccentric turning
• It’s a process special turning.
• Used in manufacturing of
cam shaft , crank shaft
35. Drilling
• For Making a axial hole
in the work piece , the
drill bit is mounted on
the tail stock as shown
in fig.
36. Reaming
• Its performed on
the drilled hole
for removing
burrs.
• It’s a polishing
process or fine
finishing process
37. Boring
• Its used to
enlarge the dia
of the already
drilled hole
• The tool is
mounted on the
bar.
38. Milling
• The work is mounted
on the compound
rest with clamp . And
the multipoint cutter
is mounted in the
head stock
39. Grinding
• A special
grinding wheel is
mounted parallel
to the lathe bed.
• This kind of
process is used
to make
recessing,
polishing works
40. Tapping
• It’s a process of making
internal threads using a
multi point tool called
Tap.
41. Thread cutting
• To producing helical groove in the
cylindrical work piece.
• Here the job is held between the
centers and the tool is
automatically fed longitudinally by
using lock nut and lead screw
arrangement.
• Depend on the pitch to be cut on
the work piece , the required
speed can be altered by using
change gears.
• The longitudinal feed should be
equal to the pitch of the thread to
be cut per revolution of the work.
• A ratio b/w the rotation of
headstock spindle with work piece
and longitudinal feed is found out
so that the screw of a desired
pitch can be obtained.
42. Teeth calculations
If the pitch of the lead screw is 6mm
and the pitch of the work is 2mm
By calculation we found that the
spindle must rote 3 times the speed
of the lead screw
44. External Thread Cutting
• The job is turned to the require
diameter and its held between the
centers.
• Then the required speed is chosen
by using calculations.
• Now the lead screw is rotated ¼ th
of the spindle speed
• Now the lock nut is engaged for
automatic movement of carriage.
• After one helical cut the the tool is
adjusted to required depth . This is
done for getting the required
shape of thread as required.
46. TAPER TURNING
• Its defined as a uniform change in the diameter of the work
piece measured along its length
• It’s a process of making conical surface along the cylindrical
work piece
• D – Larger diameter of the taper
• d - Small diameter of the taper
• L – length of the tapered part
• Α – Half taper Angle
CONICITY , K = (D- d) / L
47. TAPER TURNING METHODS
• Form tool method
• Tail stock set over method
• Compound rest method
• Taper turning attachment method
48. Form tool method
• Its one of the
simplest method of
producing small taper
in the work piece.
• The tool is ground to
the required angle.
• Then the tool is fed
perpendicular to the
work piece
50. Tail stock set over method
• In this the tail stock is off set to some required
angle
51. Tail stock set over method
• This method is employed when the taper angle is less than 8
degree
• Here the work piece is held between the centers and the tail
stock is shifted from the lathe axis by adjusting the screws.
• This kind of method is for long and less tapered jobs.
52. Compound rest Method
• This is for doing steep
and short work pieces.
• Here the compound rest
is tilted up to 45 degree
• Tanα=D-d/2l
α=Half taper angle
53. Taper turning attachment method
This attachment is placed on the rear
bed of the lathe with bracket
This arrangement can swiveled to a
maximum angle of 10 degree on either
side
55. POWER ESTIMATION
• It’s a product of cutting force and velocity.
Power required Wc =
Cutting
Speed x
velocity of cutting
Or
cutting speed
Wc = Fc x V
56. Involvement of shear and friction
power due to shear
= power due to friction
+
Wc = Ws + Wf
(Fc x V) = (Fs x Vs) + (Ff x Vf)
Fs – Shear Force
Vs – Velocity of shear
Ff - Friction force
Vf - Velocity due to friction
57. In oblique Cutting
• In this the resultant force is calculated by considering the
forces acting in three directions
Fc = Fz2
Fy
Fx2
2
Fx – Force acting in X - X Direction
Fy – Force acting in Y - Y Direction
Fz – Force acting in Z - Z Direction
58. Measuring instruments
To estimate the power the following instruments are required
• Dynamometer
• Ammeter
• Wattmeter
• Calorimeter
• Thermo Couple
Among these mostly we are using dynamometer for measuring
cutting force
59. Mechanical Tool Force Dynamometer
• A sensitive dial indicator fitted in the tool holder
• Cutting force and thrust force is measured in terms of spring
deflections.
• The deflection in terms of sensitivity
• The corresponding values are indicated in dial indicators.
60. Strain Gauge Turning Dynamometer
• This bridge circuit is fitted in the tool holder
• One set of 4 gauges are connected for measuring cutting force
• Initial balancing given to the circuit using galvanometer
• The variations are taken in terms of resistance in galvanometer.
• This reading is converted in to cutting force using suitable scale.
61. Cuttingspeed
• Cutting speed for turning is the speed at
which the work rotates. This is also
known as surface speed
62. 47-42
CuttingSpeed
• Rate at which point on work circumference
travels past cutting tool
• expressed in meters per minute (m/min)
• Important to use correct speed for material
–Too high: cutting-tool break down
rapidly
–Too low: time lost, low production rates
64. • The hardness of the cutting tool material has a
great deal to do with the recommended cutting
speed. The harder the cutting tool material, the
faster the cutting speed. The softer the cutting
tool material, the slower the recommended
cutting speed
65. • The depth of the cut and the feed rate will also
affect the cutting speed, but not to as great an
extent as the work hardness
66. Factorsthat Determine cuttingspeed
• Thematerial being cut
• Therigidity and condition of themachine
• Thematerial of which the toolis made from
• Thedepth of cut and the feedrate
• Availability of coolant (cuttingfluid)
67. SettingSpeedson aLathe
• Speedsmeasured in revolutions per minute
– Changedby stepped pulleys or gearlevers
• Belt-driven lathe
– Various speedsobtained by changing flat belt
and back gear drive
• Geared-head lathe
– Speeds changed by moving speed levers
into proper positions according to r/min
chart fastened to headstock
Safety Note!! NEVER changespeeds
when lathe isrunning.
68. 48
Setting Speeds on a Lathe
• Speeds m e a s u r e d in revo utions per
minute
– Changed by stepped pulleys or gear levers
• Belt-driven lathe
– Various speeds obtained by changing flat belt
and back gear drive
• Geared-head lathe
– Speeds changed by moving speed levers into
proper positions according to r/min chart
fastened to headstock
69. LatheCuttingSpeeds
Material beingcut Cutting speed(metres/minute
• Mild steel
• Cast iron
• High carbon steel
• Brass
• Bronze
• Aluminium
20 to 28
18 to 25
12 to 18
45 to 90
15 to 21
Upto 300
47-49
70. 47-50
CalculatingLathecuttingspeed
• Given in metres per minute
• spindle speed of machine (N) and
diameter of work must be known
• S (m/min)= πDN/1000
• Where π= 22/7 or 3.142
•
•
D= diameter of material
N= Spindle
speed(rev/min)
71. Calculating Lathe Spindle speed
(rev/min)
D
N(rev/min)
1 0 0 0 xS
S (m/min)= cutting speed
Where π= 22/7 or 3.142
D= diameter of material N=
Spindle speed(rev/min
73. INTRODUCTION
• In ordinary lathe the tool changing and setting will take more time,
so the total production will be affected.
• So to minimize cost of production , we going to introduce some
special lathe called semi automatic lathe.
• Here the tool are preset. More than one tool used to complete the
work in the job
• So during machining the tool changing and setting time is minimized.
So its suitable for mass production
• In semi automatic machine loading and un-loading of work piece ,
bringing the tool to require position, coolant on off, selecting
require spindle speeds are done manually. The tool changing done
automatically.
• Capstan and turret lathe are the two types of semi
automatic lathe
78. PARTS
• Capstan lathe – for small and light duty work
• Turret lathe – for heavy duty lathe
MAIN PARTS
Bed
Head stock
Cross slide
Turret head and saddle
Preset stops or Feed stops rods
79. Bed
It’s a heavy base , over this we have all other parts
Cross slide
it has two types
1. Reach over type – its mounted on bed guide ways b/w head
stock and turret. It has two tool post. One is at the front
having four faces of square turret for mounting tools. Each
tool can be rotated to 90 degree . Stop bars are used to
control the movement of tools. The tool can move in
perpendicular and parallel to spindle axis
Rear post having parting off tool only
2. slide hung type
This has no rear post . It has great swing . So it can do work on
larger dia work piece
80. .
• Head Stock
Turret and capstan lathe having heavy and larger head stock and
powerful motor of 30 – 2000 rpm speeds is fitted
Types
1. Step cone pulley driven head stock
2. Direct electric motor driven head stock
3. All geared head stock
4. Pre selective Head stock – It has a friction clutches.
so we can do rapid stopping and starting . Also speed changing
for different machining operations can be done by simply
pushing a button or pulling a lever.
The required speed of the next operation can also be selected
in advance
81. .
• Turret Head
It’s a hexagonal block having six faces with a bore for mounting
six or more than six tools at a time. The turret head is
mounted on a ram on a saddle. The forward movement of
ram is controlled by a preset adjustable stop.
To index the cutting tool, the ram or turret is returned to its
starting position for tripping the stops.
Each tool is indexing to
60 degree by the
rotation of circular plate.
82. • Saddle
In Capstan Lathe – Turret head
mounted on ram which is slides on
saddle.
In Turret Lathe - Turret head
mounted directly on saddle. Which
slides bed ways during machining
84. Geneva Mechanism
• It’s a automatic indexing type to index the turret by 1/6 of a
revolution, the ram is returned to the starting position.
• Then the next tool comes into position to perform the
machining operation
• Turret head, an index plate , a bevel gear and ratchet are
mounted on the same vertical spindle of the saddle. A spring
actuated plunger is used to lock the index plate which
prevents the rotation of turret during machining.
• When turret trips the stop, the plunger is released with the
help of spring loaded cam and a pin already fitted with
plunger. So the index plate is free to rotate
• Then the indexing pawl is engaged with ratchet and rotates
1/6 or 60 deg. Of revolution. When the turret moves forward,
again the plunger locks the index plate.
86. Bar Feeding Mechanism
• In capstan and turret lathes, the bar is fed automatically without
stopping the lathe which reduces the production time
• The bar stock passes through a chuck and hollow spindle of the
lathe. The bar is fitted with the bar chuck by set screws.
• The chuck rotates in a sleeve along with bar. The loose sleeve is
housed on a sliding bracket which slides over a sliding bar.
• Its again attached to one end of a chain.
• A suspended weight is hanging at the other end of a chain to exert
a constant force on the bar chuck towards right.
• When the bar is released by the collet, the force due to weight will
feed the work towards right.
• It continues till the work piece butts against the bar stop held in
the turret. Then the collet is closed
87. Turret and capstan lathe
• The bar feeding mechanism used to supply the work piece.
• Six tools of turret head, four tools in front tool post and one tool in
rear tool post are used.
• The movement of front and rear tool post is controlled by pre-set
stop
• According to the order sequence of operations, the tool move
forward while machining by the turret head
• After completing each operation the turret head moves backward to
index the tool automatically along with adjustable stops.
• These stops control the forward movement of turret
S.NO OPERATION tool post
1 Drilling, boring , reaming, counter boring, turning
and threading tools
Hexagonal turret head
2 Forming , Chamfering, Knurling and necking tools Front tool post
3 Parting Off tool Rear Tool Post
88. SPECIFICATION OF TURRET AND CAPSTAN LATHE
• Based on the size of the work piece, swing over cross slide
and swing over bed
• If Turret Lathe is specified --- 80 – 150 – 225
Here 80 – diameter
150 – swing over cross slide
225 – swing over bed
And also based on
1. no. of spindle speeds
2. No. of feeds for the carriage
3. No. of feeds for the turret or saddle
4. Weight of the machine
5. Floor space occupied
6. Motor power
89. ADVANTAGES OF TURRET LATHE
1. Production Rate is high
2. Heavier and larger work piece can be chucking
3. Wide range of speeds
4. Large no . Of tools can be used
5. More than one operation can be performed at the
same time
6. More rigid.
7. Semi skilled operators are enough
8. Less labour cost
90. Difference
S.NO Capstan Lathe Turret Lathe
1 Turret head is mounted on a ram,
which slides on saddle
Turret head is directly mounted on
saddle, which slides on bed
2 Turret movement is limited Turret moves on the entire length of the
bed without any restriction
3 So shorter work piece can be
machined
Longer work piece can be machined
4 Less rigidity More rigidity
5 Only for light duty operations Used for heavy duty operations
6 Only 60 mm dia work piece only
machined
125 - 200mm dia work piece only
machined
7 No cross wise movement to turret For facing and turning operation there is
a cross wise movement
8 Turret head moved manually Turret head moved automatically
9 Over hung type of cross wise not
used
For some specific operations overhung
used
92. 1. COLLETS
• Its a device used to hold the different size of
work piece. They are having slits in its body for
spring action. The work piece is gripped in the
hole safely
93. Types of collets
1. Draw Back Collets
2. Push out Collets
3. Dead length Collets
94. 1.Draw Back Collets
• The taper of collet is smoothly
converged towards left side.
• The collet is fitted inside a taper
portion of the spindle nose
• A thrust tube is used to move the
collet provided behind the collet in
the spindle by moving axially either
a hand wheel or lever
• This action clamps the bar stock by
applying pressure on the collet and
pushes axially in ward
• So the collet is pushed in ward to
clamp the work piece
95. 2. Push out collet
• In this the taper of the collet
converges towards the right end.
• To clamp the stock, the collet is
pushed into the tapered hole by the
thrust tube which closes the jaws
and grips the work piece
• To unclamp or release the work
piece from the collet, the collet will
be pushed in
96. 3.Dead length collet
• While gripping ,the work piece
may move inward or outward in
the above two methods
• This difficulty is rectified by
providing a sliding sleeve in
between the spindle and collet
• When the work piece is
clamped the sleeve pushes
through thrust tube by applying
force on the collet.
• So there is no axial movement
either inward and outward
97. .
• Its used to grip the
heavy w/p quickly.
• Its operated either by
pneumatically or
hydraulically.
• The air cylinder
placed at the back of
the head stock. A
piston rod connects
the piston and jaws
by links which is
actuated by sliding
piston.
2.Power chuck
It has to air passage shown in fig.
when the compressed air admitted in the right of
the piston, it pushes the piston and jaw towards
left. So the work is gripped in the chuck tightly.
When the air passed through left passage , it
pushes the piston to move to right side. So the jaw
released and work held free in the chuck.
98. • It’s a simple specially designed device used to
hold the identical work pieces.
• Used in mass production
• Its mounted on spindle
• So the loading and unloading become easy in
lathe.
3. Fixture
99. TOOL HOLDING DEVICES
• Various types of tool holders are fitted in hexagonal turret ,
front tool post and rear tool post.
1. Straight cutter tool holder
2. Adjustable angle cuter tool holder
3. Multiple cutter holder
4. Offset cutter holder
5. Sliding tool holder
6. Knee tool holder
7. Flange tool holder
8. Roller steady box tool holder
9. Combination tool holder
10. Self opening type die holder
11. Knurling tool holder
12. Collapsible taps
13. Tap holder
114. Before starting the work, the following works are carried out
1. Selection of tools
2. Designing of special tools
3. Selection of speeds
4. Selection of feeds
5. Setting the require length of the work piece and tool travel length
These planning of operation in turret or capstan lathe is called Tool – Layout
THREE STAGES IN LAYOUT
1. Planning and scheduling
2. Detailed sketching and sequencing the operation
3. Sketching of work piece and tool movement
SIMPLE TOOL LAYOUTS
115. PROBLEM -1 -Prepare a tool layout of square headed bolt
from a square bar stock using a turret lathe
123. INTRODUCTION - Automats
Automatic lathe or simply automats are the machine tool in
which all operations are required to finish off the work piece
are done automatically without the attention of an operator
All the operations including loading and unloading are done
automatically
By using the control system , all the working and idle operations
are performed in a definite sequence
124. Advantages of Automatic Lathe over
conventional lathe
1. Mass production of identical parts
2. High accuracy is maintained
3. Production time minimized
4. Less floor space required
5. Unskilled labour is enough. So labour cost minimized
6. Constant flow of production
7. One operator can supervise more than one machine .
8. The bar stock is fed automatically
125. Classification of Automats
1. According to the type of work material used
a) Bar stock Machine
Bar type of work materials are machined to produce screws ,
nuts, rings, studs etc. collects are used to hold the work piece
b) Chucking Machine
blank type of components are produced in this machine. the
components are held in jaw chuck or special fixtures
126. Classification of Automats
2. According to the number of spindles
a) Single spindle Automats
These machines having only one spindle. So one component
can be machined at a time
EXAMPLE : Automatic cutting off machine
Automatic Screw Cutting Machine
Swiss Type Machine
b) Multi Spindle Automats
These machines have 2 to 8 spindles. operators performed
simultaneously in all spindles. So the rate of production is high
TYPES – Parallel Action Type
Progressive Action Type
127. Classification of Automats
• According to the arrangements of spindles
a) Horizontal spindle
The spindles are in horizontal position. These are
used to machine lengthy work piece with small dia.
b) Vertical Spindle
Here the spindles are in vertical position. These
machines are heavier and stronger.
Used to machine larger diameter & small length
work pieces
128. Classification of Automats
• According to the feed control
a) Single cam shaft rotating at constant speed
Here a single cam control the working and idle motion of the
tool. Both the things are happened at same time
b) Single cam shaft with two speeds
The cam rotate at slow speed at working motion. And rotates
faster speed during idle motion. So the idle time is reduced.
c) Two cam shaft
(i) Main Cam Shaft – Tool movement during working are
controlled by main cam shaft . It rotates at slow speed
(ii) Auxiliary Cam shaft – The tool movement during idle
motion is controlled by auxiliary cam shaft. Here the cam shaft
rotes at faster speed. So idle time is reduced.
129. Classification of Automats
• According to the Use
a) Single Purpose Machine
This machine is designed to produce single component of
fixed shape and size.
b) General Purpose Machine
This machine is designed to produce variety of components
with slight variations in shape and size
132. Automatic Cutting Off Machine
• These are the simple design machine used to produce large
quantities of small dia – shorter length work pieces.
• 2 cross slides are mounted for doing the work in front and
rear tool post.
• The operations are turning , facing , chamfering , under
cutting, forming and parting-off.
• It has single cam shaft – so the working and idle strokes are
done at same speed.
• In some time we also use end working slide to perform
drilling and reaming operations.
• The size of parts vary from 3 to 20mm diameter.
134. Automatic Screw cutting machine
• This is also called turret type automatic screw cutting machine .
Because it has turret head.
• This machine is used for producing small screws of all types
• We can do internal and external operations in this machine like
drilling , reaming , boring , spot facing, threading, tapering,
turning , forming and under cutting.
• It has one cam shaft with 3 plates of cam for
controlling the movement of front tool post , rear tool
post and top tool post.
• The turret head movement is controlled by lead cam.
It give slow forward and slow return to the turret.
135. Parts to be Produced in
Automatic Screw Cutting Machine
137. Swiss Type Screw Cutting Machine
• This machine is first developed in switzerland. So we
call it as Swiss type screw cutting machine.
• Its also called sliding head stock machine or movable
head stock machine.
• These machines are used to produce lengthy work
piece with small diameter ( 2 to 25mm)
138. Features of
Swiss Type Screw Cutting Machine
1. Sliding head stock
2. A tool bracket having 4 to 5 tool slides
3. A special attachment called feed base
4. A cam shaft.
139. Swiss Type Screw Cutting Machine
1. Sliding Head Stock
The head stock has a collet. The bar stock
held in collet. The head stock slides along
the guide ways of the bed. A bell cam in the
cam shaft controls the sliding of head stock
140. Swiss Type Screw Cutting Machine
2.Tool Bracket
The tool bracket mounted on
the bed near to head stock.
It has 5 tool slides . Two
placed front and rear and
others placed radially.
The tools are moved front and
back in the guide ways.
The tool movement is
controlled by rocker arm and
plate cams.
The plate cams are placed in
the cam shaft
141. Swiss Type Screw Cutting Machine
3.Feed Base
• This is placed at the right of the lathe.
• Used to perform operations like drilling , boring , thread cutting
• The movement of this controlled by plate cams in cam shaft
142. .
• 4.Cam shaft
This have bell cam and plate cams. Plate cams are used
to control the movement of tool posts.
WORKING
The bar stock is held in the rotating spindle by the collet.
The moving head stock give longitudinal feed to the w/p.
All the tools perform the operation at the same time.
one revolution of cam shaft produce one component.
145. MULTI SPINDLE AUTOMATS
• They are having 2 to 8 spindles. The operation carried
out simultaneously in all spindles.
• So the rate of production is high
CLASSIFICATION
According to type of work piece
1. Bar type 2. Chucking type machine
According to the arrangements of spindles
1. Horizontal 2. Vertical spindle
According to the principle of operation
1. Parallel action 2. Progressive action
146. Parallel action Multi spindle Automatic
Machine
• Here the work piece is
finished in one working
cycle.
• Rate of production is high
• Suitable for producing
small parts of simple
shape from bar stock
148. Progressive actionMulti spindle Automatic
Machine
• The head stock has spindle carrier. And it rotates about
the horizontal axis of the machine
• There is one tool slide corresponds to each spindle.
• The tool slide move towards the work spindle during
machining
• During the indexing of spindle carrier the work is done
in every station.
• At the end of tools six station , the work is completed.
