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MACHINING PROCESS
LATHE• Lathe is the most general purpose machine tool.
• The work piece is held and rotated against suitable cutting tool.
• It has provision to hold the workpiece and to rotate it about an
axis.
• If the cutting tool is moved parallel to the axis of rotation of the
work, then a cylindrical surface is produced
• If the tool is moved perpendicular to the axis of rotation of the
work, then flat surface is obtained.
lathe
PARTS OF LATHE
FEED MECHANISM : LONGITUDINAL, CROSS FEED AND ANGULAR FEED
Tail stockchuck
Lead screw bed
carriage Tool post
SPECIFICATION OF LATHE• The overall length of bed
• Largest diameter of the work piece that can be rotated (height of live and dead center above the bed)
• Distance between the centers (max w/p length)
• Range of spindle speed
• Power rating of electric motor
• Diameter of lead screw and number and range of threads that can be cut.
OPERATIONS PERFORMED ON LATHE1. TURNING- Obtaining cylindrical surface2. TAPER TURNING
METHODS3. FORMING TOOL METHODE
HOLDING OF W/P - CHUCK AND LATHE CENTERS
2. TAIL STOCK SET OVER METHODE
The principle of this method is to shift the axis of rotation of the w/p at an angle to the lathe axis and feeding the tool parallel to the lathe axis.
The taper angle will be twice the inclination of the axis.
• 3. COMPOUND REST METHOD
Swiveling angle should be half of the taper angle
Turning
Taper turning
• THREAD CUTTING
Thread can be cut either on outside or inside of the w/p called external and internal thread respectively
Pitch- lead screw – gear adjustment
Thread cutting
• KNURLING
ROUGHENING A SMOOTH SURFACE
knurling
SHAPING MACHINE
Function- production of flat surface
Single point tool
Tool reciprocatesFrwd stroke—cut
PRINCIPLE PARTS OF A SHAPER
-----
RAMQuick return mechanism---ram
Slower cutting stroke
Faster return stroke
Shaping machine
Planer Machine• Planer Machines are used to
produce flat surfaces by a stationary single point cutting tool.
• The table on which workpiece is clamped moves against the tool.
• The feed is given to the cutting tool.
• Planer machine is capable of holding very large workpiece which cannot be accomodated by a shaper machine.
Slotter Machine• In slotter machine the
tool reciprocates in vertical axis.
• Cutting action is only during the downward stroke.
• It operates on the same principle as that of shaper
DRILLING MACHINE
• Drilling is the operation of
making holes in a workpiece
by forcing a rotating tool
called drill against it.
• Main parts are: Base
Column
Table
Drill Head
Drilling machine
OPERATIONS ON DRILLING MACHINE
1. DRILLING (a)2. REAMING (b)3. BORING4. COUNTER BORING (c)5. COUNTER SINKING (d)6. TAPING (e)
Drilling:It Is the Operation of producing circular hole using a drill by removing metal from the workpiece.Reaming:It Is the Operation of finishing a hole using a reamer.Boring:It Is the Opreation of enlarging a hole.Counter Boring:It is the operation of increasing the diameter of a hole for a certain distance.Counter Sinking:It is the operation of creating a cone shape at the end of a hole.Taping:It is the operation of cutting internal threads by means of a tool called TAP.
MILLINGUP MILLING
(Conventional Milling)DOWN MILLING(Climb Milling)
• Milling is the process of removing metal by feeding the workpiece against a rotating multipoint cutter. As the cutter rotates, each cutting edge removes a small amount of material from the workpiece.
In up milling the workpiece is fed
against the rotating milling
cutter.
In down milling the workpiece is
fed in the same direction of that
of rotating milling cutter.
Milling machine
Milling machines can be classified as
1. Horizontal Milling Machine
2. Vertical Milling Machine
Horizontal Milling Machine
Vertical Milling Machine
MILLING OPERATIONS
1. PLAIN MILLING 2. FACE MILLING
• 3. SIDE MILLING 4. END MILLING
• 5. T SLOT MILLING 6. ANGULAR MILLING
• 7. FORM MILLING 8. GEAR CUTTING
GRINDING
Grinding is the process of metal
removal in which the cutting tool used
is an abrasive wheel.
It is used for the following purposes
1. To remove small amount of metal
from workpiece.
2. To obtain better surface finish
3. To machine hard surfaces
4. To sharpen cutting tools
Grinding machine
TYPES OF GRINDING• 1. CYLINDRICAL GRINDING
Grinding wheelsMade of abrasive materials
bonded together.2 types1. Natural : sand stone,
emery, diamonds etc.2. Artificial : silicon
Carbide, Aluminium oxide, boron carbide etc.
• 2. SURFACE GRINDING 3. FORM GRINDING
NC Machines• It is the method of controlling
manufacturing operations by means of numerical instructions.
• A programme is prepared by the programmer after product drawing and process planning
• This programme is recorded in a magnetic tape and fed to the control unit.
• This unit sends signals to the machine through position command unit.
CNC Machines• It is the method of controlling
manufacturing operations by
means of a computer.
• A CNC code is generated by the
computer after product drawing
and process planning
• The computer send signals to the
machine as per the CNC code.