machine tools manuals 250214

8/16/2019 Machine Tools Manuals 250214

1/32

LATHE MACHINE

Introduction:-

A lathe is probably the oldest machine tool, stemming from the early

tree lathe, which was turned by a rope passed around the work a few times and attached to

a springly branch over head. The work was supported by two levels struck in adjacent

trees. The operators foot supplied the motion, which was intermittent and fluctuating. The

tool was held in the operations hand. Later a strip of wood called as “Lathe” was used tosupport the rope and hence named as “Lathe”. rom this crode beginning and over period

of more than two centuries, the modern engine lathe has evolved.

Working Principles:-

Lathe removes undesired material from a rotating work piece in the form

of chips with help of tool which is transverse across the work and can be deep in work.

The tool material should be harder than the work piece and lathe held securely and rigidly

on the machine. The tool may be given linear motion in any direction. A lathe is used

principally to produce cylindrical surfaces and planes, at right angles to a!is of rotation. "t

can also produce tapers and bellows etc operation of turning is done on parts as small as

these used by watches to huge parts weighing several tons.

Fig1: Working principle of lt!eFunction#$ The function of a lathe is to remove e!cess material in the form of chips by

rotating the work %iece against a cutting tool to produce cylindrical shapes. The tool

material should be harder than the work piece. The tool may be given liner motion along

work piece in any direction.

&


2/32

Fig": Prts of Center lt!e #c!ine

$i%e &or' specifiction of lt!e:-

&. The height of the centers measured form the lathe bed.

'. The swing diameter over bed.

(. )a!imum job length held between the two centers.

*. The swing diameter over carriage.Prts of Lt!e:-

&. +ase or +ed. '. ead stock. (. Tail stock. *. -arriage. . -ross /lide. 0.-ompound

rest. 1. Apron. 2. Lead /crew. 3. Tool %ost.

Prts (escription:

&. )ed# The bed is a heavy, rugged casting in which are mounted the working parts of the lathe. "t

carries the headstock and tail stock for supporting the workpiece and provides a base for the

movement of carriage assembly which carries the tool.

'. Legs# The legs carry the entire load of machine and are firmly secured to floor by foundation

bolts.

(. Hedstock # The headstock is clamped on the left hand side of the bed and it serves as housing

for the driving pulleys, back gears, headstock spindle, live centre and the feed reverse gear. The

headstock spindle is a hollow cylindrical shaft that provides a drive from the motor to work

holding devices.

*. *er )o+# The 4uick$change gear$bo! is placed below the headstock and contains a number of

different si5ed gears.

Fig,: $c!e#tic digr# of lt!e

(


3/32

. Crrige# The carriage is located between the headstock and tailstock and serves the purpose

of supporting, guiding and feeding the tool against the job during operation. The main parts of

carriage are#

a6 The saddle is an $shaped casting mounted on the top of lathe ways. "t provides support to

cross$slide, compound rest and tool post.

b6 The cross slide is mounted on the top of saddle, and it provides a mounted or automatic crossmovement for the cutting tool.

c6 The compound rest is fitted on the top of cross slide and is used to support the tool post and the

cutting tool.

d6 The tool post is mounted on the compound rest, and it rigidly clamps the cutting tool or tool

holder at the proper height relative to the work centre line.

e6 The apron is fastened to the saddle and it houses the gears, clutches and levers re4uired to

move the carriage or cross slide. The engagement of split nut lever and the automatic feed lever at

the same time is prevented she carriage along the lathe bed.

0. Tilstock # The tailstock is a movable casting located opposite the headstock on the ways of the

bed. The tailstock can slide along the bed to accommodate different lengths of workpiece between

the centers. A tailstock clamp is provided to lock the tailstock at any desired position. The

tailstock spindle has an internal taper to hold the dead centre and the tapered shank tools such as

reamers and drills.

Lt!e opertions:-

/.78. /e4uence of operation -utting tool.

&. acing acing ./././ingle point tool

%lain Turning ./././ingle point tool

/tep9 :nder cut. /ingle point tool ; %arting tool.

Taper Turning. ./././ingle point tool


4/32

d @ small diameter of taper in mm

L @ Length of tapered part in mm.

'@ full taper angle. ? @ half taper angle.

Met!ods of tpers:-

&. /etting over the tail stock centre.

'. +y swiveling the compound rest.

(. +y a taper turning attachment.

*. +y combining longitudinal and cross feed in a special lathe.

. +y forming tool method.

Fig/: Tpes 0f Lt!e 0pertions

C!#fering:- "t is the operation of beveling the e!treme end of the work piece. This is

done to remove burrs, to protect the end of the work piece from being damaged and to

have a better look.

nurling:-


5/32


6/32

*D

E '&

'D'D(D

E &2

E'*

E '.*

All dimensions are in FmmG

. +efore turning the workpiece conical holes must be provided at the ends

and turning may be done with side cutting tool.

$TEP T56NIN*:-

&. Arrange the workpiece between the headstock and tailstock.'. The parting tool can be fi!ed to tool post perpendicular to the workpiece.

(. The machine is started after the workpiece is properly set. Hive the

minimum feed and move the tool up to re4uired length.

*. Iepeat the process for attaining diameter &2mm 9 &*mm.

TAPE6 T56NIN*:-

&. The =$tool is selected for the taper turning and is fi!ed to the tool post.

The cutting edge should be perpendicular to the lathe a!is.

'. /tart with a minimum feed and rotation of compound slide screw which

cause tool to be feed at re4uired taper angles.

(. or every feed measure the smaller dia. >hich should be &2mm increase

the feed and rotate the compound slide screw once again for a good

surface finish.

P6ECA5TI0N$:-

&. /liding parts of lathe should be cleaned and lubricated.

'. /peed selector control shouldnGt be changed when spindle is rotating.

(. -huck should be secured properly.

*. -hips should be cleaned using a brush.

. Hoggles should be used which working on lathe.

6E$5LT:-

The workpiece is step turned, taper turned, threaded 9 knurled as per the

dimensions shown in figure.

$TEP T56NIN*

&&


7/32

*D

E '&

'D'D(D

E &2

E'*

E '.*


TAPE6 T56NIN*

E3P4N0:"

TH6EA( C5TTIN* AN( N56LIN* 0N LATHE MACHINE

AIM: - To perform the following operations on the given work piece using lathe

machine

&. /tep turning

'. Taper turning

(. Thread cutting

*.


8/32

*. /tart the machine with direct speed.

. +efore turning the workpiece conical holes must be provided at the ends

and turning may be done with side cutting tool.

$TEP T56NIN*:-a. Arrange the workpiece between the headstock and tailstock.

b. The parting tool can be fi!ed to tool post perpendicular to the workpiece.

c. The machine is started after the workpiece is properly set. Hive the

minimum feed and move the tool up to re4uired length.

d. Iepeat the process for attaining diameter &2mm 9 &*mm.

TAPE6 T56NIN*:-

a. The =$tool is selected for the taper turning and is fi!ed to the tool post.

The cutting edge should be perpendicular to the lathe a!is.

b. /tart with a minimum feed and rotation of compound slide screw which

cause tool to be feed at re4uired taper angles.

c. or every feed measure the smaller dia. >hich should be &2mm increase

the feed and rotate the compound slide screw once again for a good

surface finish.

TH6EA( C5TTIN*:-

&. -hange the gears and arrange them as per the re4uired pitch. The gears

must be arranged as per the table mentions to respective pitch.

'. 8ne part is selected on the screw and half nut lever is engaged now the

lever moves in the a!is at the workpiece direction.

(. The depth of cut usually varies from D. to 'mm is applied by advancing

the tool perpendicular to the a!is at workpiece.

*. A pitch of *mm say is usually set and pitch gauge is used to check the

correctness of the pitch.

CHAMFE6IN*:-

&. /liding parts, spindles, tools are lubricated sufficiently.

&


9/32

*D

E '&

'D'D(D

E &2

E'*

E '.*


'. The workpiece must be fitted tightly in the chuck and tool advances.

(. The tool is fed and up to the end gets chamfered.

N56LIN*:-

&. or this process, knurling tool is held rigidly on tool post.

'. The rollers are pressed against revolving workpiece to s4ee5e the metal

against the multiple cutting edges producing impossible in a regular

pattern surface with slow speed.

P6ECA5TI0N$:-

0. /liding parts of lathe should be cleaned and lubricated.

1. /peed selector control shouldnGt be changed when spindle is rotating.

2. -huck should be secured properly.

3. -hips should be cleaned using a brush.

&D. Hoggles should be used which working on lathe.

6E$5LT:-

The workpiece is step turned, taper turned, threaded 9 knurled as per the

dimensions shown in figure.

$TEP T56NIN*

&1


10/32

*D

E '&

'D'D(D

E &2

E'*

E '.*


*D

E '&

'D'D(D

E &2

E'*

E '.*


TAPE6 T56NIN*

TH6EA( C5TTIN*

&3


11/32

*D

E '&

'D'D(D

E &2

E'*

E '.*


N56LIN*

4(6ILLIN* MACHINE

Introduction: -

rilling is the process of making cylindrical holes in the work piece. "t is one of the most

important machine tool in the workshop. rilling machine is one of the simplest,

moderate and accurate machine tool. "t consists of a spindle, which imports rotary motion

to the drilling tool. The tool used for drilling holes is called the drill bit. "n this the rotary

motion is given to the tool and the work is stationery. rilling is a process of making a

hole in an object by forcing a rotating tool called drill. The same operation can be

performed in a lathe by holding the drill stationary and rotating work.

'&


12/32

Fig5: RADIAL DRILLING MACHINE

Working principle# The rotating edge of the drill e!erts a large force on the workpiece

and the hole is generated. The removal of metal in a drilling operation is by shearing and

e!trusion.

Fig9: Working principle of drilling #c!ine

Tpes of drilling #c!ines:-&. %ortable drilling m;c.,'. /ensitive drilling m;c. (Hang

drilling m;c. *. Iadial drilling m;c. . Automatic drilling m;c. Btc.6A(IAL (6ILLIN* MACHINE#$ "t is intended for drilling small and large holes on a

heavy work piece. This consists of a heavy round vertical column, mounted on a large

base. The column supports a radial arm which can be raised and lowered to accommodate

work piece of different heights. The arm may be swung around to any position over work

bed. The three movements in radial drilling machines when combined together permit to

be located at any desired point on a large work piece for drilling.

PA6T$ 0F A (6ILLIN* MC.#$ +ase, column, Iadical arm, Blevating screw, rill

head, rill spindle, Table, )otor for elevating the arm, )otor for driving spindle.

&. )se# The base is a heavy casting that supports the machine structureJ it provides rigidmounting for the column and stability for the machine. The base is usually provided with

'(


13/32

holes and slots which help to +olt the base to a table or bench and allow the work$holding

device or the workpiece to be fastened to the base.

'. Colu#n# The column is a vertical post that -olumn holds the worktable and the head

containing the driving mechanism. The column may be of round or bo! section.

(. T;le# The table, either rectangular or round. rill machine;press in shape supports theworkpiece and is carried by the vertical column. The surface of the table is 3D$degree to

the column and it can be raised, lowered and swiveled around it. The table can be

clamp;hold the re4uired the workpiece. /lots are provided in most tables to allow the jigs,

fi!tures or large workpieces to be securely fi!ed directly to the table.

Fig


14/32

a6 -ontact speed motor is mounted at e!treme end of

radial arm.

b6 Train of gearing within the drill head

/.78. /e4uence of operation Tool used

&. )arking =ernier height gauge, /urface plate.

'. %unching ot punch, hammer.

(. %ilot$holed drill rill bit.

*. rilling rill bit.

. Ieaming Ieamer

0. +oring +oring tool.

1. -ounter +oring -ounter bore drill.

2. -ounter /inking -ounter /ink drill

)arking#$ +efore drilling any hole on the given work piece, the center of the hole is

located by drawing two lines at angles to each by means of venire height gauge placed onsurface plate.

%unching#$ After locating a center, identification is made at the point where the hole is to

be drilled. %inching is done by means of center punch and ball peen hammer

%ilot$holed drill# +efore drilling a hole of a larger diameter, a pilot hole of K(mm which

is slightly Hrater then the width of the chisel edge must be drilled. The reason is that the

action of the chisel edge during drilling is more or less an e!trusion process. /o 2D to

2 of total thrust, i.e., vertically upward force will come on chisel edge which increases

the power re4uired and decreases the tool life. This refers to eliminate the thrust acting on

the chisel edge pilot hole is made prior to drilling.

rilling#$ "t is the operation of producing a cylindrical hole by removing metal by therotating edge of a cutting tool called the drill. The drilling is the one of the simplest

methods of producing a hole. rilling does not produce an accurate hole.

Ieaming#$ "t is an aureate away of si5ing and finishing a hole which has been already

drilled. "n order to finish a hole and bring it to the accurate si5e. The hole reamer is made

half that of drilling and used for reaming is known as reamer, which has multiple cutting

edges, reamer can not originate a hole, its simply follows the path, which has been

previously drilled and removes small amount of metal, the materiel removed by this

process is around D.(3mm and for the accurate work, this should not e!ceed D.&'mm.

+oring#$ To enlarge a hole by means of an adjustable cutting tool with only one

cutting edge, this is necessary where suitable si5ed drilled is not available or whole

diameter is so large that it can be ordinary drilled. To finish a hole accurately and to bringit to the re4uired si5e. To machine the internal surface of the hole already producing. To

correct all of roundness of the hole. To correct the location of hole as be boring tool

follows as independent path with respect to the hole.

-ounter +oring#$ The enlarged hole forms a s4uare shoulder with the original hole. This

is necessary is some cases to accommodate the heads of bolts, studs and pins. The tool

used for this is called counter bore. The counter bores are made with straight or tapered

shank to fit in the drills spindle. -ounter boring can give accurately of about K D.DDmm.

The cutting speed for counter boring is ' less than that of drilling operations.

'1


15/32

Fig>: Tpes 0f (rilling 0pertions

-ounter /inking#$ "t is the operation of making a cone shaped enlargement of the end of

a hole to %rovide a recess of a flat head screw or counter sink rivet fillet in the hole. The

Tool used for counter sinking is called counter sink standard counter sinkers have 0D

D ,

2'

D

and 3DD inclined angle that the cutting edges of tool are formed at the conical surface. The

cutting speed in counter sinking is ' less than that of drilling.

rill -hucks#$ A drill chuck is a device intended for holding smaller si5e drills. "t has

two or more adjustable jaws set radially to hold straight shank drills. "t is provided with a

taper shank which is fitted in the tapered hole of the spindle. These are made in

various si5es.

Twist rills#$ "t is an end cutting tool. "t is the most common type of tool used in drilling.

"t consists of a cylindrical piece of steel with special grooves called flutes

TypeGs twist drills# $ &6 %arallel shank twist drill. '6 Taper shank twist drill.

(rills #terils: $ -utting portion$$$$ igh speed steel /hank portion. $$$$-arbon steel.

-utting speed# $ "t is a measure of peripheral speed of the drill in operation e!pressed in

m;min. -utting speed C/6 @ M 7 ; &DDD m;min.

is the diameter of the drill in mm

7 is the r.p.m of the drill spindle.

eed @ the feed of a drill is the distances the drill moves into the work at each

revolution of the spindle. "t is e!pressed in mm; revolution or per min

The feed for min. @ eed per revolution N rpm

epth of cut @ the depth of cut in drilling is e4ual to one half of the drill

diameter.

E3P N0:,&' (6ILLIN* 0PE6ATI0N

AIM: -

To drill a hole on the given workpiece as per dimensions.

T00L$ 6E85I6E(: -

rill bit K &' mm.

MATE6IAL: -

-. ". circular blank.

'3


16/32

E &*mm

E 2Dmm9 'Dmm Thick

P60CE(56E: -

&. The given plate is fi!ed in the machine vice perfectly.

'. 8n the metal plate a point is marked at the central of the plate.

(. The drill feed handle is rotated counter clockwise so that the tool comes down

and make that the tool point coincide with marked point.*. The motor id started and slowly the feed is given to the tool.

. The hole had been done by the tool id checked by making the spindle up and

down.

0. The hole is checked for given dimension.

1. >hile removing plate first switch off the motor and the removed.

2. The hole is slightly higher in dia as the fit.

P6ECA5TI0N$: -

&. The feed must be ade4uate otherwise the drill bit may damage.

'. :se goggles when the operation is going.

(. >hen the operation is going, hold the metal tightly with benchvise jaws.

6E$5LT: -

The hole is drilled on the plate as per given dimensions.

E3P4N0:,&;'

TAPPIN* 0PE6ATI0N

A")# $

To tap the given hole internally and to make threads and e!ternal threads on the rod.

T00L$ 6E85I6E(: -

"nternal tapping tool, B!ternal threading die.

(&


17/32

E &*mm

E 2Dmm

9 'Dmm Thick

MATE6IAL: - -." circular blank

INTE6NAL TH6EA(IN* P60CE(56E: -

&. The tool is inserted in the hole.

'. The tool is turned in the forward direction for same rotation and reversed to

remove the chips that are in minute form.(. The oil is applied mean while for smooth operation.

*. The procedure is repeated until the hole gets threaded cleanly.

E3TE6NAL TH6EA(IN* P60CE(56E: $

&. The e!ternal tapping die is mounted on the rod and oil is applied.

'. The die is rotated until the thread impression occurs on rod and then rotated in

anticlockwise direction to remove the chips.

(. The procedure is repeated until the rod gets fully threaded.

6E$5LT: -

The internal threads and e!ternal threads are produced and the rod is inserted into the

hole.

((


18/32

)&' N p&.1 mm

INTE6NAL TH6EA(IN*

E3TE6NAL TH6EA(IN*

$HAPIN* MACHINE

(


19/32

Introduction:- The shaping machine is used for producing flat surfaces. )achining on

shaper more economical with easier work setting and cheaper tooling. 8n a shaper job is

fi!ed on able and the cuing tool reciprocates across the work piece. The tool cuts on

forward stroke and the return stroke remain idle. As there is no cutti3ng action in return

stroke, we deploy 4uick return mechanism to reduce cutting time. To produce flat

surfaces, channel sections, =$ channels and gear teeths.etc.

Fig 1/:$!ping Mc!ine

Working Principle: The job is rigidly fi!ed on the machine table. The single point

cutting tool held properly in the tool post is mounted on a reciprocating ram. The

reciprocating motion of the ram is obtained by a 4uick return motion mechanism. As theram reciprocates, the tool cuts the material during its forward stroke. uring return, there

is no cutting action and this stroke is called the idle stroke. The forward and return

strokes constitute one operating cycle of the shaper.

Fig1?: Working Principle 0f $!ping Mc!ine

Tpes of #ec!nis#s:- &. -rank shaper# "n construction the crank shaper employs a

crank mechanism to change circular motion of the bull gear to reciprocating motion of the

(1

>ork piece

Tool


20/32

ram. The bull gear receives power either from an individual motor from an over head line

shaft if it is a bell drive shaft.

'. Hear type shaper# this type of shaper carries a rack under it is ram which is driven by a

spur gear. The pinionCspur gear6 machining with the rack is driven by a gear drive. The

speed andthe direction in which the machine traverse depend on the number of gears in

the gear train.

(. ydraulic type# "n these shapers hydraulic pressure is used for driving the ram .it has

become very popular and is also more efficient than the both of the above tool.

Prts of t!e s!per:

&. +ase. '. -olumn (. -ross slide *, saddle . Table 0. -lapper bo! 1.

Iam 2. Tool head. 3. eed disc. Blevating screw. etc

Construction# The main parts of the /haper machine is +ase, +ody C%illar, rame, -olumn6,

-ross rail, Iam and tool head CTool %ost, Tool /lide, -lamper +o! +lock6.

)se# The base is a heavy cast iron casting which is fi!ed to the shop floor. "t supports the body

frame and the entire load of the machine. The base absorbs and withstands vibrations and other

forces which are likely to be induced during the shaping operations.

)od &Pillr7 Fr#e7 Colu#n': "t is mounted on the base and houses the drive mechanism

compressing the main drives, the gear bo! and the 4uick return mechanism for the ram

movement. The top of the body provides guide ways for the ram and its front provides the guide

ways for the cross rail.

Cross ril: The cross rail is mounted on the front of the body frame and can be moved up and

down. The vertical movement of the cross rail permits jobs of different heights to be

accommodated below the tool. /liding along the cross rail is a saddle which carries the work table.

6# nd tool !ed: The ram is driven back and forth in its slides by the slotted link mechanism.

The back and forth movement of ram is called stroke and it can be adjusted according to the

length of the workpiece to be$machined.

Fig19: Prts 0f A $!per

(3


21/32

Cutting sped:- "n a shaper the cutting action is intermittent and is considered only during

the forward cutting stroke.

Length of cutting stroke.

-utting sped#$ $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

Time re4uired by the cutting stroke.

Feed:- "t is the relative movement of the tool or work in a direction perpendicular tothe a!is of reciprocation of the ram for double stroke. "n is e!pressed in

mm. The feed is always

given at the end of return stroke when the tool is not cutting the metal.

(ept! of cut:- "t is the thickness of metal that is removed in one cut. "t is the

perpendicular distances measured between machined surface and non

machined surface of the work piece.

$pecifictions:&. )a!imum length of the stroke of ram

'. -utting to return stroke ratio.

(. 7o and amount of feed

*. Type of speed reduction.. Type of drive and 4uick mechanism

BN%.78#*

*&


22/32

MAIN* 0F FLAT $56FACE 0N $HAPIN* MACHINE

AIM: -

To generate flat surface according to the given dimensions by using shaping

machine.T00L$ 6E85I6E(: -

&. =$tool,

'. scriber,

(. steel rule and

*. center punch.

MATE6IAL 6E85I6E(: -

-." s4uare bar

P60CE(56E:-

&. )easure the dimensions of a given mild steel block.

'. i! the block in the shape vice and tight it fully.

(. +y providing a depth of cut of say D.* for rough finish and D.'mm for finish

remove the e!cess material on block by a .-.- tool until the re4uired

dimensions are obtained.

*. Apply chalk on the face of the block and mark the dimensions as shown in

figure.

. %unching is done by pilot punch along the marking lines.

0. Adjust the tip of tool such that it touches the metal piece and by providing

re4uired depth of cut, the machine is started.

1. /hape the material by increasing the feed and depth of cut

%IB-A:T"87/#$

-heck the tool not to cross the face of the material.

&. /lowly increase the feed of tool.

'. -heck dimensions for every stroke.

(. /et the workpiece e!actly below the tool before starting the machine.

6E$5LT:- /haping operation is performed for the given workpiece.

*(


23/32

'

$L0TTIN* MACHINE

*

ALL ")B7/"87/ AIB "7 mm


24/32

Introduction: The slotting machine is a reciprocating machine tool in which, the ram

holding the tool reciprocates in a vertical a!is and the cutting action of the tool is only

during the downward stroke.

Construction# The slotter can be considered as a vertical shaper and its main parts are:

&. +ase, column and table

'. Iam and tool head assembly

(. /addle and cross slide

*. Iam drive mechanism and feed mechanism.

The base of the slotting machine is rigidly built to take up all the cutting forces. The frontface of the vertical column has guide ways for Tool the reciprocating ram. The ram

supports the tool head to which the tool is attached. The workpiece is mounted on the

table which can be given longitudinal, cross and rotary feed motion.

The slotting machine is used for cutting grooves, keys and slotes of various shapes

making regular and irregular surfaces both internal and e!ternal cutting internal and

e!ternal gears and profiles The slotter machine can be used on any type of work where

vertical tool movement is considered essential and advantageous.

The different types of slotting machines are#

&. Punc! slotter# a heavy duty rigid machine designed for removing large amount of

metal from large forgings or castings

'. Tool roo# slotter# a heavy machine which is designed to operate at high speeds. This

machine takes light cuts and gives accurate finishing.

(. Production slotter# a heavy duty slotter consisting of heavy cast base and heavy

frame, and is generally made in two parts.

E3P4N0:?

*1


25/32

$L0TTIN* 0PE6ATI0N

AIM: -

To cut a keyway on given circular blank according to the given dimensions by

using slotting machine.

T00L$ 6E85I6E(: -

&. /lotter

'. scriber,

(. steel rule

*. center punch.

MATE6IAL 6E85I6E(: -

-." circular blank of dimensions C2D "A ! 'D T"-


26/32

E 2Dmm9 'Dmm Thick

AO0 N * mm

*. 7ever attempt to remove chips or reach across the table while the ram is in

motion.

6E$5LT: -

The re4uired groove is obtained on mild steel plate according to given dimensions.

&


27/32

MILLIN* MACHINE

Introduction:- )illing is a machining process in which metal is removed by rotating

multi$edge cutting tool called “milling cutter”, while the work piece fed against to it. A

milling machine is a machine tool that removes metal chips. >ork is fed against a

rotation multipoint cutter. "t removes metal at a very fast rate. The job movement is

hori5ontal, vertical and cross feeding.

GENERAL MILLING MACHINES

A milling machine is a machine tool that removes metal as the work is fed against a

rotating multipoint cutter. The cutter rotates at a high speed and because of the multiple

cutting edges it removes metal at a very fast rate. The machine can also hold one or more

no of cutters at a time. This is why a milling machine finds wide application in production

work. This is superior to other machine as regards accuracy and better surface finish and

is designed for machining a variety of tool room work.

Fig @ : nee And Colu#n Tpe Milling Mc!ine

Principle:-The milling machine mechanism is composed of spindle drive mechanism and

the table feed mechanism. The spindle drive mechanism is incorporated in the column.

All modern machines are driven by individual motors housed within the column, the

spindle receives power from a combination of gears and clutch assembly. )ultiple speedof the spindle may be obtained by attaining the gear ratio.

Fig1:Working principle of #illing #c!ine

(


28/32

PA6T$ (E$C6IPTI0N:%arts of milling m;c#$

&.+ase. '. -olumn. (.


29/32

0. 0=er rm# The 8ver arm is mounted at the top of the column and is guided in perfect

alignment by the machined surfaces. The 8ver arm is the support for the arbor.

1. Ar;or support# The arbor support is fitted to the 8ver arm and can be clamped at any location

on the 8ver arm. "ts function is to align and support various arbors. The arbor is a machined shaft

that holds and drives the cutters.

2. Ele=ting screB# The upward and downward movement to the knee and the table is given bythe elevating screw that is operated by hand or an automatic feed.

Types of milling m;c.#$ -olumn and knee type.

&. ori5ontal milling. '. =ertical milling. (. :niversal milling.

*. 8mniversal milling.

)illing m;c. mechanism#$

The spindle drive mechanism is incorporated in the column. All modern machines aredriven by individual motors housed within the column, and the spindle reeves power from

a combination of gears and clutch assembly. )ultiple speeds of the spindly may be

obtained by altering the gear ratio.

>ork holding devices#$ T$ bolts and clamps, =$blocks, Angle plate, =ices, etc.

-utter holding devices#$ Arbors, collets, Adapters, /pring collets, +olted cutters, /crew

C a 6 :p milling # The up milling which is also called conventional milling, is the process

of removing the metal by a cutter which is rotated against the direction of travel of thework piece.

C b 6 own milling # The down milling which is also called climb milling, is the process

of removing the metal by a cutter which is rotated in the same the direction of travel of

the work piece.

-utting speed#$ The cutting speed of a milling cutter is its peripheral linear speed

resulting from rotation. "t is e!pressed in meters per minute. The cutting speed can be

derived formula.

=@ M d n ; &DDD minutes per min.

=@ the cutting speed in inch per min.

d@ the diameter of the cutter in mm.

n@ the cutter speed in rpm.

eed#$ The feed in a milling machine is defined as the rate with which the work piece

Advances under the cutter.

epth of cut#$ The depth of cut in milling is the thickness of the material moved in one

pass of the work under the cutter.

1


30/32

E3P4N0:9

*EA6 C5TTIN* 0N MILLIN* MACHINE

AIM:-

To cut a spur gear on a given wooden specimen.MATE6IAL:- -ircular wooden specimen.

T00L$ 6E85I6E( :-

&. Hear tooth vernier

'. )illing cutter

(. /teel rule

P60CE(56E:-

&. The given workpiece is checked for dimensions.

'. rom the calculations no. of holes and no. of hole circles are known.

(. The workpiece is set in the machine correctly.

*. 7umber of holes and no. of hole circles are set on the inde! plate of the dividing

head.

. The cutter is first made to touch the workpiece and then the feed of mm is given.

0. After cutting one teeth the feed removed to cut ne!t teeth, the inde! circle is

rotated for one revolution as per remained number of tools.

1. the process is repeated, the remained number of teeth are cut.

P6ECA5TI0N$:

&. -heck the straightness of the a!is of work piece within the live centre of the

dividing head

'. should be careful while performing the inde!ing

6E$5LT:

Hear cutting on milling machine is performed successfully.

3


31/32

2D

'D

'D

0&


32/32

machine tools manuals 250214

Documents