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Akhilesh Kumar Kanik
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Lathe machines
fig. the lathe machine .
definition: A lathe machine is a machine tool which is used to remove metals from a workpiece to give a desired shape and size. In other words it is a machine that is used to hold the workpiece to perform various metal removing operations such as turning, grooving, chamfering, knurling, facing, forming etc with the help of tools. It is also called as mother of machine.
types of lathe machines:
The four main types of lathes are
Speed Lathes
Engine Lathes
Tool Room Lathes and
Turret Lathes
So let’s start .
Speed Lathes
It is very simple is design. It only has headstock, tailstock and a very simple tool post. It can operate in 3-4 speeds. The spindle speed is very high. It is used for light machine works like wood turning, metal spinning and metal polishing.
Engine Lathes
Engine lathes are the most common types of lathe machine. It is designed for low poweroperations as well as high power operations. Various lengths of the machine is available. The length can be up to 60 feet. Engine lathe is commonly seen in every machine shop. Various metals can be machines. The machine can operates at a wide range of speed ratios.
Engine Lathes
Tool room Lathes
It is a very versatile lathe machine. It can give better accuracy and finishing . It has wider range of speeds . It can give different types of feeds. It can be a great device to manufacture die.
Turret Lathes
It is a great machine for quick operations. It has various types of tool posts mounted on a single structure. As a number of tools are set up on machine, the job can be completed very quickly with the help of a single setup. A capstan wheel is used to position the next tool. A sequential machining process can be done by using the turret lathe without moving the workpiece. It eliminates the error that occurs due to misalignment.
types of lathe machines - turret lathe
Special Types of Lathe Machines
These are the machines which are allows the worker to perform tasks which are not possible in normal lathe machines. These lathes include –
bench type jeweler’s lathe
Automatic lathes
brakedrum lathes
multispindle lathes
crankshaft lathes
duplicating lathes
Please read :
Types of Chips Produced in Machining Operations
Types of Operations in Lathe Machines
Forming and generating methods
Laser Beam Machining process
CNC Lathe Machine Parts
Conventional machining operation always produces some chips. The nature of the chips depend on
operation
properties of the workpiece material
cutting environment
The cutting tool has to overcome the resistance of the work material to give it a desired shape. So cutting tool must be more harder, wear resistance than the w/p. The main reason for the chip formation is due to the deformation by shear stress. This stress is applied to metal lying ahead of the cutting edge of the tool . Four main types of chips in machining process are –
Discontinuous Chips
Continuous or Ribbon Type Chips
Continuous Chip Built-up-Edge (BUE)
Serrated Chips
Discontinuous Chips:
Main reason of discontinuous chip formation is the deformation due to repeated fracturing. Hard and brittle metals like C.I , bronze and brass are prone to produce discontinuous chips. These are small pieces which are loosely connected to each other.
Discontinuous Chips formation
Continuous or Ribbon Type Chips:
In this type of chip formation the chips are bonded together and form long coils. These are continuous chips which undergo continuous plastic deformation. There isn’t any fracture ahead of the cutting edge of the tool. The inside part of the chip shows steps due to intermittent slip. The outside is smooth.
Types chips continuous chips
Continuous Chip Built Up Edge:
These are very similar to the ribbon type chips but it is not as smooth as those. These chips are seen in the workpieces with poor surface finish. These chips protect the cutting edge from wear because of the chips movement. The tool life increases by the action of heat.
continuous chips with built up edges
Serrated Chips:
These are semi-continuous . They posses a saw tooth profile. The main reason reason for this appearance is the alternating high shear strain followed by a low shear strain. These chips are seen metals like titanium alloys, austenitic stainless steel and nickel based super alloys which are very difficult to machine. When materials are cut at very high speed these chips are likely to be formed.
various operations performed on Lathe machine: As we know that the lathe machine is used for producing basically cylindrical and conical shape jobs with the help of various tools. Different shapes are produced by different operations. Some of operations are as follows:
Turning
Turning
Turning is the operation when the metal removal takes place from the surface of the cylindrical work piece. In this process the tool is fed along the axis of the spindle. Turning is the removal of metal from the outer diameter of a rotating cylindrical work piece. Turning is used to reduce the diameter of the work piece, usually to a specified dimension, and to produce a smooth finish on the metal. Often the work piece will be turned so that adjacent sections have different diameters.
Shoulder Turning
Shoulder turning
A shoulder is a point at which the diameter of the work piece changes with no taper from one diameter to the other. In other words, there is a 90 degree face moving from one diameter to the other. To get a nice square edge it must be machined with a tool having sharp point. It should be ground to an angle of less than 90 degrees so that it can work right down into the corner of the shoulder. To get a nice square face on the shoulder it will be needed to make a facing cut. While doing so the carriage should be locked. This gives the best result. Face of the shoulder should be cleaned up by locking the carriage until it is square. While using sharp pointed tool it will needed to use fairly high RPM, say 1500, and advancing the tool slowly otherwise it will get little grooves from the pointed tip instead of a nice smooth finish. Finally, sharp corners are to be removed by using a file to make a nice beveled edge on outside edge of the shoulder and on the end of the work piece.
Facing
Facing is the process of making flat surfaces on a lathe. The job is held on a faceplate or chuck and the tool is fed at right angles to the bed to obtain flat surfaces. Most often, the work piece is cylindrical, but using a 4- jaw chuck you can face rectangular or odd-shaped work to form cubes and other non-cylindrical shapes. To safely perform a facing operation the end of the work piece must be as close as possible to the jaws of the chuck. The work piece should not extend more than 2-3 times its diameter from the chuck jaws unless a steady rest is used to support the free end.
Boring
Boring
The process of removal of stock from a hole in the workpiece is called boring. Holes are bored by single point cutting tools. The cutting tool shaves off a thin layer of material to an accurate size. Tapered holes are bored in the same manner as in the case of taper turning. The boring processing is said to be difficult for some of the following reasons:
(a) It is hard to see the processing surface.
(b) The scraps are kept in the hole. When the scraps are kept, the surface cannot be finished to high roughness.
(c) Because we cannot see the bottom of a deep hole, it is hard to stop the boring bar at the bottom location. We must depend on the scale of the lathe and the sound.
(d) Especially the case of a small hole, the backside of the boring bar touches the material. We must set the height of the edge suitably.
(e) Because a boring bar is long, the tool has vibrations easily. It is dependent on the rigidity of the boring bar.
Drilling
Drilling
This is the process of making holes in the workpiece with the help of drills. The drill is held in the tailstock and the drilling operation is c
fig. the lathe machine .
definition: A lathe machine is a machine tool which is used to remove metals from a workpiece to give a desired shape and size. In other words it is a machine that is used to hold the workpiece to perform various metal removing operations such as turning, grooving, chamfering, knurling, facing, forming etc with the help of tools. It is also called as mother of machine.
types of lathe machines:
The four main types of lathes are
Speed Lathes
Engine Lathes
Tool Room Lathes and
Turret Lathes
So let’s start .
Speed Lathes
It is very simple is design. It only has headstock, tailstock and a very simple tool post. It can operate in 3-4 speeds. The spindle speed is very high. It is used for light machine works like wood turning, metal spinning and metal polishing.
Engine Lathes
Engine lathes are the most common types of lathe machine. It is designed for low poweroperations as well as high power operations. Various lengths of the machine is available. The length can be up to 60 feet. Engine lathe is commonly seen in every machine shop. Various metals can be machines. The machine can operates at a wide range of speed ratios.
Engine Lathes
Tool room Lathes
It is a very versatile lathe machine. It can give better accuracy and finishing . It has wider range of speeds . It can give different types of feeds. It can be a great device to manufacture die.
Turret Lathes
It is a great machine for quick operations. It has various types of tool posts mounted on a single structure. As a number of tools are set up on machine, the job can be completed very quickly with the help of a single setup. A capstan wheel is used to position the next tool. A sequential machining process can be done by using the turret lathe without moving the workpiece. It eliminates the error that occurs due to misalignment.
types of lathe machines - turret lathe
Special Types of Lathe Machines
These are the machines which are allows the worker to perform tasks which are not possible in normal lathe machines. These lathes include –
bench type jeweler’s lathe
Automatic lathes
brakedrum lathes
multispindle lathes
crankshaft lathes
duplicating lathes
Please read :
Types of Chips Produced in Machining Operations
Types of Operations in Lathe Machines
Forming and generating methods
Laser Beam Machining process
CNC Lathe Machine Parts
Conventional machining operation always produces some chips. The nature of the chips depend on
operation
properties of the workpiece material
cutting environment
The cutting tool has to overcome the resistance of the work material to give it a desired shape. So cutting tool must be more harder, wear resistance than the w/p. The main reason for the chip formation is due to the deformation by shear stress. This stress is applied to metal lying ahead of the cutting edge of the tool . Four main types of chips in machining process are –
Discontinuous Chips
Continuous or Ribbon Type Chips
Continuous Chip Built-up-Edge (BUE)
Serrated Chips
Discontinuous Chips:
Main reason of discontinuous chip formation is the deformation due to repeated fracturing. Hard and brittle metals like C.I , bronze and brass are prone to produce discontinuous chips. These are small pieces which are loosely connected to each other.
Discontinuous Chips formation
Continuous or Ribbon Type Chips:
In this type of chip formation the chips are bonded together and form long coils. These are continuous chips which undergo continuous plastic deformation. There isn’t any fracture ahead of the cutting edge of the tool. The inside part of the chip shows steps due to intermittent slip. The outside is smooth.
Types chips continuous chips
Continuous Chip Built Up Edge:
These are very similar to the ribbon type chips but it is not as smooth as those. These chips are seen in the workpieces with poor surface finish. These chips protect the cutting edge from wear because of the chips movement. The tool life increases by the action of heat.
continuous chips with built up edges
Serrated Chips:
These are semi-continuous . They posses a saw tooth profile. The main reason reason for this appearance is the alternating high shear strain followed by a low shear strain. These chips are seen metals like titanium alloys, austenitic stainless steel and nickel based super alloys which are very difficult to machine. When materials are cut at very high speed these chips are likely to be formed.
various operations performed on Lathe machine: As we know that the lathe machine is used for producing basically cylindrical and conical shape jobs with the help of various tools. Different shapes are produced by different operations. Some of operations are as follows:
Turning
Turning
Turning is the operation when the metal removal takes place from the surface of the cylindrical work piece. In this process the tool is fed along the axis of the spindle. Turning is the removal of metal from the outer diameter of a rotating cylindrical work piece. Turning is used to reduce the diameter of the work piece, usually to a specified dimension, and to produce a smooth finish on the metal. Often the work piece will be turned so that adjacent sections have different diameters.
Shoulder Turning
Shoulder turning
A shoulder is a point at which the diameter of the work piece changes with no taper from one diameter to the other. In other words, there is a 90 degree face moving from one diameter to the other. To get a nice square edge it must be machined with a tool having sharp point. It should be ground to an angle of less than 90 degrees so that it can work right down into the corner of the shoulder. To get a nice square face on the shoulder it will be needed to make a facing cut. While doing so the carriage should be locked. This gives the best result. Face of the shoulder should be cleaned up by locking the carriage until it is square. While using sharp pointed tool it will needed to use fairly high RPM, say 1500, and advancing the tool slowly otherwise it will get little grooves from the pointed tip instead of a nice smooth finish. Finally, sharp corners are to be removed by using a file to make a nice beveled edge on outside edge of the shoulder and on the end of the work piece.
Facing
Facing is the process of making flat surfaces on a lathe. The job is held on a faceplate or chuck and the tool is fed at right angles to the bed to obtain flat surfaces. Most often, the work piece is cylindrical, but using a 4- jaw chuck you can face rectangular or odd-shaped work to form cubes and other non-cylindrical shapes. To safely perform a facing operation the end of the work piece must be as close as possible to the jaws of the chuck. The work piece should not extend more than 2-3 times its diameter from the chuck jaws unless a steady rest is used to support the free end.
Boring
Boring
The process of removal of stock from a hole in the workpiece is called boring. Holes are bored by single point cutting tools. The cutting tool shaves off a thin layer of material to an accurate size. Tapered holes are bored in the same manner as in the case of taper turning. The boring processing is said to be difficult for some of the following reasons:
(a) It is hard to see the processing surface.
(b) The scraps are kept in the hole. When the scraps are kept, the surface cannot be finished to high roughness.
(c) Because we cannot see the bottom of a deep hole, it is hard to stop the boring bar at the bottom location. We must depend on the scale of the lathe and the sound.
(d) Especially the case of a small hole, the backside of the boring bar touches the material. We must set the height of the edge suitably.
(e) Because a boring bar is long, the tool has vibrations easily. It is dependent on the rigidity of the boring bar.
Drilling
Drilling
This is the process of making holes in the workpiece with the help of drills. The drill is held in the tailstock and the drilling operation is c
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