Slide 1

UNIT-3SHAPING , SLOTTING & PLANING MACHINESByD. Kanaka RajaDepartment of mechanical engineering,AITS

2Shaping Machine is also called Shaper

3What is a shaper ?A Machine which produces flat surfaces

A Ram holding the Tool reciprocates

Work is fed perpendicular to the tool

4Shaper - working principle

WORKTOOLBA

In the shaper, the cutting tool has a reciprocating motion, and it cuts only during the forward stroke.

Cutting Tool repeatedly travels along line A B

Work is fed a small distance each time

Feed of work & line of tool motion are in same plane but perpendicular

5 Working principle Contd.The tool line eventually reaches position C D

Combination of two movements results in the flat plane ABCD being machined

BADC

6Classification of shapersBasic types:

Horizontal Shaper

Vertical Shaper

Traveling head Shaper

7 Horizontal shaper:Ram holding the cutting tool moves In horizontal plane

Vertical shaper:The cutting tool moves in vertical plane

Traveling head shaper:Cutting tool reciprocates & moves cross wise simultaneously.

8Detailed classification

M305.239 a) Push Type Shaper 1. Acc. to Cutting Stroke action b) Draw Type Shaper

a) Standard Shaper 2. Acc. to the Table Design: b) Universal Shaper a) Crank type 3. Acc. to Driving Mechanism: b) Geared type c) Hydraulic

Shaper

10Push type shaperMetal is removed when the ram moves away from column

Most common type used in practice

Unless otherwise specified, the term shaper refers to Push type Shaper

11Draw type shaperMetal is removed when the tool is drawn towards the column

Allows heavier cuts to be made

Less vibration during cutting

12 Standard shaper Work Table can be moved Vertically & Horizontally. it cannot swivelled or tilted. Universal shaper Table can be moved Horizontally Vertically Swivelled & Tilted This is mostly used in Tool Rooms

13 Crank type shaper:Driving mechanism is by crank and a slotted lever quick return motion mechanism is used to give reciprocating motion to the ram.The crank is adjustable and is arranged inside the body of bull gear.

Geared type shaper:Driven by Rack & Pinion mechanism

Hydraulic shaper:Driven by oil pressure developed by a pump, which is run by an electric motor.It is more efficient than the crank and geared type shapers.

14

SHAPING MACHINE - Working

15SHAPING MACHINE - PARTS

BASECOLUMNRAM

CROSS RAILTABLE

TOOL

16Main parts of a shaping machine

1. BASE 5. CROSS RAIL

2. COLUMN 6. SADDLE

3. RAM 7. TOOL HEAD

4. TABLE 8. CLAPPER BOX

17

Constructional details of a shaperBASETABLECROSS RAILRAM

TOOL HEAD

RAM CLAMP

CLUTCH

COLUMN

TOOL POST

BASE

18Parts - functions 1. BaseBottom most partSupports other parts of the machineActs as a reservoir of lubricating oilMade of Cast Iron

BASE

192. Column

Vertically mounted on the baseHouses Driving Mechanism of RamHas guide ways on which Ram slidesMade of Cast Iron

COLUMN

203. Ram

The main moving part of a Shaper It carries Tool Head Connected to Driving Mechanism

R A M

214.Table

A box like casting with T-slots on its topShaper vice is fitted in the T-slotsWork is fixed in the vice

TABLE

225. Cross railUsed to move the Table Up & DownUpward movement is controlled by an Elevating ScrewSide movement is controlled by lead screw

CROSSRAIL

236. Saddle

It is mounted on cross rail It supports the TableMoves across the cross rail left to rightMovement obtained by a cross feed screw

SADDLE

CROSS RAIL

247. Tool head

It is attached to the front end of RamCarries Clapper box & Tool post on itCan be swiveled at any angle on either side

TOOL HEAD

TOOL POST

CLAPPER BOX

258. Clapper boxIt is hinged to the tool headIt houses clapper blockSwings outward in return strokeTool post mounted on clapper block

CLAPPER BOX

25

26

Specifications of Shaping MachineMax. length of Stroke of RamType of DrivePower inputFloor Space requiredWeight of the MachineCutting to Return Stroke ratioFeed Size of tableMaximum horizontal and vertical travel of the table

27Working of shaperShaper drive Mechanism changes rotary motion of power source (Electric motor) to reciprocating motion of Ram.Material removal (cutting) of work piece takes place in the forward stroke of ram. The return stroke of the ram does no cutting, hence is called Idle stroke.The Ram with cutting tool has to move slowly in cutting stroke.

28Since return stroke does no cutting the ram should move faster during return stroke.The shaper drive system incorporates quick return mechanism. So that the ram moves faster during return strokeThus minimizing the (idle time) Quick Return time.Working of shaper

29Shaper OperationsMachining Horizontal Surfaces

Machining Vertical Surfaces

Machining Angular Surfaces

Cutting Slots, Grooves & Key ways

Machining irregular surfaces

Machining Splines / Cutting Gears

30Steps for MachiningWork is properly held in a viceTable is raised to a gap of 25 to 30 mm between tool & workThe length & position of stroke are adjustedThe length of stroke should be nearly 20 mm longer than the work

31Steps for MachiningThe approach & over run should be 10 & 5 mm respectively.

Depth of cut is adjusted by rotating down the feed screw of tool head

Feed is adjusted about half the width of cutting edge of tool

32Machining Horizontal SurfacesFix the work properly on the tableAdjust the length of strokeSet the required cutting speedGive required feed of the tableFix an appropriate tool in the tool headGive suitable depth of cut for rough cutsFinishing the job by giving less depth of cut

33Machining Horizontal Surfaces

34Machining Vertical SurfacesFix up the job on the table firmlyAlign the surface to be machined properlyFix up a side cutting tool in the tool headSet the vertical slide exactly at zeroSwivel the apron away from the jobSwitch on the machine Rotate down feed screw by hand to give down feedFeed in about 0.25 mm

35Machining Vertical Surfaces

36Machining Angular SurfacesAngular shaping is carried out to machine inclined surfaces, bevelled, dove tail etc.,Set the work on the tableSwivel the vertical slide of tool head to the required angle ( to the left or right)Set apron away from work Give down feed as per requirement

37Machining Angular Surfaces

38Cutting Rack or SplinesFix up a square nose tool in tool headAdjust the length & position of strokeReduce the cutting speedGive suitable depth of cut Feed the work properly to get equal splines

39Cutting Rack or Splines

40Cutting Key waysFix up the job between two centresCut first spline similar to a key wayMove / Rotate work by the required amountUse index plate for this purpose

41Cutting Key ways (At the end)

42Cutting Key ways (Midway)

43Machining irregular surfacesFix up a forming tool in tool postGive cross feed in conjunction with down feed Swivel the apron suitably according to the contour required

44Machining irregular surfaces

WORK

TOOL

Advantages and limitations of shaperAdvantagesThe set up is very quick and easy and can be readily changed from one job to another.The work can held easily.The single point tools used are in inexpensive;These tools can be easily grounded to any desired shape.Lower first cost.The cutting stroke has a definite stopping point.Because lower cutting forces, thin and fragile jobs can be conventionally machined on shapers.

LimitationsBy nature is a slow machine because of its straight line, forward and return stroke. The single point tool requires several strokes to complete a work.The cutting speeds are not usually very high speeds of reciprocating motion due to high inertia forces developed in the motion of the units and components of the machine. Owing to these reasons the shaper does not find ready adaptability for assembly and production line.

46 Shaper Driving Mechanisms

Whitworth quick return mechanismSlotted link quick return mechanismHydraulic quick return mechanism

47Quick Return Mechanism

Q.R.M

48Whitworth Quick Return Mechanism

49Whitworth Quick Return Mechanism

50Whitworth Quick Return Mechanism

51Whitworth Quick Return Mechanism

52Crank BC revolves at a uniform speed.During cutting stroke point C travels from Y to X through Z.Ram returns at high speed as the crank rotates from X to Y through T.Then: Time for cutting stroke 360 - Time for return stroke Since is smaller than 360 , the time for cutting is more than the idle time. Stroke length can be changed by varying the radius AE

=Whitworth Quick Return Mechanism

53

Crank & Slotted Link

54Crank & Slotted Link QRM

55Main Parts of the Mechanism

BULLGEARBULLGEAR SLIDING BLOCKCRANK PINBULLGEAR SLIDELEAD SCREWBEVEL GEARS

ROCKER ARM SLIDING BLOCK

56

Line diagram ofCrank & Slotted lever Mechanism

Driving PinionSlotted Lever Crank pinLead ScrewClamping leverRamRam BlockBevel GearsBull gear Sliding block Lever Sliding blockBull GearBull gear SlidePivot Bevel Gears

57 Elements of the MechanismCrank pin(11) is fitted in the slotted link(9)Bottom end of slotted link (rocker arm) is attached to frame of column(15)Its upper end is connected to ram(2).

58Working PrincipleElectric motor drives pinion (1)Pinion (1) drives the bull gear(14)A Radial slide (16) is bolted at the centre of bull gear.Radial slide carries a sliding block(12) & a crank pin (11)As the bull gear 14 rotates, crank pin 11 rotates.So sliding block 12 also rotates on the crank pin circle.Simultaneously crankpin will move up & down in the slot of the slotted link 9.

59Working Principle - concludedAs the crank pin11 moves, slotted link 9 gets rocking movement. This rocking movement is communicated to the ram.Thus the rotary motion of the bull gear is converted to reciprocating motion of the ram.

60PRINCIPLE OF Q.R.M.

PMNKOLC2C1

61Principle - ExplainedWhen the link is in the position PM, ram will be at the extreme backward position.

When it is at PN, ram is at extreme forward position.

PMNKOLC2C1

62 Principle - ContinuedPM&PN are tangents drawn to the crank pin circle. Forward cutting stroke takes place through the angle C1K C2Return stroke takes place through the angle C2 L C1 of the crank. It is evident that angle C2K C1 is greater than C2 L C1

PMNKOLC2C1

63Principle - Concluded

PMNKOLC2C1

Angular velocity of crank pin is constant. So Return stroke is completed in a shorter time. Therefore it is known as quick return motion.

64Ratio between cutting time & return time.

Cutting time : Return stroke = Angle C1KC2 : Angle C2LC1 Cutting time : Return time ratio usually varies bet 2 : 1.Practical limit is 3 : 2

MNKOLC2C1

Hydraulic drive

Quick return in the hydraulic shaper is accomplished by increasing the flow of hydraulic oil during the return stroke.In the hydraulic shaper the ram is connected to the hydraulic cylinder which is controlled by means of a 4 way valve.The hydraulic fluid is pumped to the hydraulic cylinder through 4 way valve; this valve is connected to the sump.The 4 way valve controls the direction of high pressure fluid into the cylinder and controls the direction of motion, either the cutting stroke or return stroke.Hydraulic drive

The flow control valve controls the flow rate of the hydraulic fluid thereby controlling the speed at which ram moves.Since the power available remains constant throughout, it is possible to utilize the full capacity of the cutting tool during the cutting stroke The starting and stopping of the machine is achieved by through a finger operator lever.An adjustable trip dog operated lever controls the operation of 4 way valve to control the ram reversible.The return or idle stroke is faster than the cutting stroke because of the smaller area in the return side of the cylinder if constant volume pump is used.Hydraulic drive

67

The cutting stroke has a more constant velocity and less vibration is induced in the hydraulic shaper.The cutting speed is generally shown on an indicator and does not require calculation.Both the cutting stroke length and its position relative to the work may be changed quickly without stopping the machine.The hydraulic feed operates while the tool is clear of work.More strokes per minute can be achieved by consuming less time for reversal and return strokes.

Advantages of hydraulic drive

The stopping point of the cutting stroke in a hydraulic shaper can vary depending upon the resistance offered to cutting by the work material.It is more expensive compared to the mechanical shaper.

Disadvantages

70Clamping the Work on a Shaper Work should be properly & firmly fixed on the Shaper table Work is fixed on the table by 3 methods. Using a Swivel Vice Using T bolts & Clamps Using Angle plate & C Clamps

Work holders

72 Using a Swivel Vice

73 Using T bolts & Clamps

Cutting speed is defined as the average linear speed in stroke in m/mm, which depends on the number of ram stokes(or ram cycles) per minute and the length of stroke.

The number of double strokes or cycles of the ram/minN= the number of double strokes or cycles of the ramL=length of the ram stroke, mmK= return stroke time Where k=2/3, 3/4Cutting speed Vc = NL(1+k)/1000 m/mm

The feed is the relative motion of the work piece in a direction perpendicular to the axis of reciprocating of the ram.Feed is given to the work piece.Depth of cut d is the thickness of the material removed in one cut,in mm.Feed

The machining timethe time required to complete one double stroke, from cutting speed Vc is given by

With a feed of f mm/double stroke, number of strokes required to machine a surface of width B will be Ns=B/f

Machining time

t = L(1+K)/1000Vc

Hence total machining the surface of width B will be

In terms of ram strokes N, the time for machining the surface is given by Ns=B/fN minMachine time tm = B/f ((L/Vc*1000)+(L /Vr *1000)Where B= width of the job mm f = feed mm/ stroke l = length of stroke, mm Vc = Cutting speed Vr = return stroke speed mm/mint = LB(1+K)/1000Vcf

Machining time

Slotting machine

89Slotting machineSlotting machine is also called as Slotter

90Line diagram of slotter

SADDLECROSSSLIDE

91Slotters

92Slotter A Machine which produces flat surfaces A Ram holding the Tool reciprocates Ram reciprocates in vertical direction Work is fed perpendicular to the tool

93Slotter - working principle

WORKTOOLBA

Cutting Tool repeatedly travels along line A BWork is fed a small distance each timeFeed of work & line of tool motion are in same plane but perpendicular

94 WORKING PRINCIPLE contd.The tool line eventually reaches position C D

Combination of two movements results in the flat plane ABCD being machined

BADC

95WORKING PRINCIPLE contd.Work is supported on a rotary table.

Table can have longitudinal and rotary movements

Straight and rotary cuts can be produced.

96CLASSIFICATIONAccording to design and purpose the slottersare classified into two typesPuncher SlotterPrecision tool room SlotterPuncher slotter:Intended for removing large amount of metal from heavy works. heavy and rigid machineRam driven by rack and spiral pinion mechanismused for machining large castings and forgings

Production slotter

98Precision tool room slotter:

Used for tool room work, where accuracy important Lighter in construction Fitted with quick return mechanism Operates at high speeds and designed for light cuts Gives accurate finish Suitable for small to medium size work pieces

99Difference between vertical shaper and Slotter

in vertical shaper the tool holding ram can tilt by about 100 with respect to vertical axis In slotter ram cannot tilt at all. In all other aspects vertical shaper and slotter are similar

M305.30100Slotting machine Introduction Having known the Working Principle we will now look at :

The Constructional Details of a slotting MachineFunction of each partSpecifications of a slotter

M305.30101Slotting machine -construction

BASE

CIRCULAR TABLE

COLUMN

RAM

CROSS SLIDE

SADDLE

T-SLOTS

TOOL HEAD

M305.30102Slotting machine

103Line diagram of slotter

104Main parts of a slotter

1. Base 5. Cross slide

2. Column 6. Saddle

3. Ram 7. Tool head

4. Table

105Parts - functions 1. BaseBottom most partSupports other parts of the machineActs as a reservoir of lubricating oilMade of Cast Iron

Contd..

106BaseRigidly built to take up cutting forcesTop of bed is accurately finishedGuide ways are provided for saddleGuide ways are perpendicular to column face

107ColumnVertically mounted on the baseHouses Driving Mechanism of RamHas guide ways on which Ram slidesMade of Cast IronAlso houses feeding mechanism

COLUMN

M305.30108RamReciprocating vertically up and down of a slotterMounted on guide ways of columnIt carries Tool Head / cutting toolConnected to Driving MechanismAn arrangement is provided on the body of ram to change length of strokeR A M

109TableIt holds the work piece.A circular casting with T-slots on its topMovement of table can be linear or rotaryTable is graduated in degrees so indexing can be doneSlotter vice may be fitted in the T-slotsWork may be fixed in the viceOperated manually or by powerTABLE

110SaddleIt is mounted on guide ways of bedIt can be moved towards or away from bedUsing saddle longitudinal feed is givenTop is accurately finished to provide guide ways for cross slideThese guide ways are perpendicular to the guide on the baseOperated either manually or by power

111Cross slideCircular work-table is mounted on the top.

Mounted on guide ways of saddle

Moves parallel to the face of the column

Using cross slide cross feed is given

Operated either manually or by power

112Tool head

It is attached to the bottom end of Ram

Carries Tool post on it

Tool is fixed in position

No swiveling along verticle axis or horizontal axis

113 Specifications of Slotting machine Max. length of Ram StrokeDiameter of work table in mm.Type of DriveMaximum table travel.Power inputFloor Space required

Specification

115Slotter driving mechanismA Slotting machine produces flat surfacesThe Ram holding the Tool reciprocates vertically up and downCuts the material only in down strokeThere should be some mechanism to move the ram in reciprocating motionIt is called as slotter driving mechanismThe mechanism commonly used is slotted disc mechanism

116Slotted disc mechanism

117Quick return mechanism (QRM)A Mechanism makes the ram to move slowly during cutting stroke.

During return stroke ram moves at a faster rate.

To reduce the idle time,It Should return quickly .

The mechanism adopted is known as QRM

118Methods to obtain Q.R.M. in slotter1. Whitworth Q.R.M. Mechanism2. Variable speed reversible motor drive mechanism3. Hydraulic drive Mechanism The mechanisms for QRM in slotter are similar to QRM in shaper

119Feed in SlotterIn Slotter feed is given by tableFeed movement is intermittentFeed is given at the beginning of the cutting strokeFeed may be given either manually or by powerTable will have three types of feed movementsa. longitudinalb. cross and c. circular feeds.

Contd

120Types of feed in SlotterLongitudinal feed:Table is fed perpendicular to the columnTable moves towards or away from the column

Cross feed:Table is fed parallel to the face of the columnCircular feed: table is rotated with respect to verticle axis

121Feed mechanism of a Slotter

Feed shaft

122Uses a ratchet and pawl mechanismFeed shaft engaged with cross, longitudinal / rotary feed screws has the ratchet mounted on it.Ratchet is moved by small amount in one direction only with the help of a connecting rod, lever.The roller moves in the cam groove cut on the face of the bull gear of slotting machine.Feed mechanism of a Slotter

123Operations on slotter 1. Machining flat surfaces

2. Machining Circular Surfaces

3. Machining internal surfaces

4. Machining grooves or key ways

124Setup for MachiningWork is properly held in a vice

Table is raised to a gap of 25 to 30 mm between tool & work

The length & position of stroke are adjusted The length of stroke should be nearly 20 mm longer than the workContd

125Setup for MachiningThe approach & over run should be 10 & 5 mm respectively.

Depth of cut is adjusted by rotating down the feed screw of tool head

Feed is adjusted about half the width of cutting edge of tool

126Machining Flat SurfacesFix the work properly on the tableAdjust the length of strokeSet the required cutting speedGive required feed of the tableTool is held in the tool head of ramRam reciprocates up and down

127Machining Flat SurfacesFeed has to be given at the beginning of cutting strokeBoth internal and external surfaces can be machinedGive suitable depth of cut for rough cutsFinishing the job by giving less depth of cut

128Machining flat surfaces

129Machining circular surfacesTool is set radially on the workWork piece is placed centrally on the rotary tableFeed is given by the rotary table feed screwFeed screw rotates the table through an arcAdjust the length of strokeSet the required cutting speedFinishing the job by giving less depth of cut

130Machining internal surfacesFix up a tool in tool postCross, longitudinal and rotary feed are combinedAny contoured surface can be machinedMostly done manuallyGood skill is required from operator

131Machining grooves or key waysSlotter is specially intended for cutting internal groovesExternal or internal gear teeth can be machinedFix up the job between two centersCut first a key wayMove / Rotate work by the required amountIndexing can be done by using graduations on rotary table

132Cutting Key waysFix up the job between two centresCut first spline similar to a key wayMove / Rotate work by the required amountUse index plate for this purpose

133

Cutting Key ways

134Work holding devices Work should be properly & firmly fixed on the Slotter table

Work is fixed on the table by 3 methods.

1. Using a Swivel Vice 2. Using T bolts & Clamps 3. Using Angle plate & C Clamps

135 Clamping the work on a Slotter is depicted in the following Slides, one by one

1361. Using a Swivel Vice

137 2. Using T bolts & Clamps

Planing machine

139Planing machine

140Another view of Planer

141

Table Movement in Planer

142

Table Movement in Planer- another view

143What is a planer ?A Machine which produces flat surfaces

Consists a stationary housing for holding the tools

A table holding the work reciprocates

Large works, that con not be accommodate on shapers

The tool is stationary but the work moves

144Planer - working principle

The table on which work is clamped is imparted a reciprocating movementCutting takes place during the forward stroke of table During return stroke the cutting tool is slightly lifted Tool is fed for each forward stroke

WORK

TOOL

Work is fixed on Table

145 WORKING PRINCIPLE contd.Table is driven by an electric motor

Length of table stroke can be adjusted

Speed of return stroke is also regulated

146Principle of operation of a planer

147Classification of planers 1. Double housing Planer 2. Open side Planer 3. Pit type Planer 4. Edge Planer or Plate Planer 5. Divided Table Planer

148

It is the Standard model & most widely usedVery heavy and robust Has a bed and two vertical housings are fixedTable moves along the guide ways of the bedHousing supports cross rail & tool heads.Cross rail carries two tool headsTool head carries tools Double housing planer:

149A double housing planer

150Open side planerIt has only one supporting column (housing)Area larger than the table can be planedCross rail is mounted as a CantileverTool holders are mounted on Cross railStroke length of bed is controlled by adjustable dogs

Open side planer

152PIT PlanerColumns and cross rail carrying tool head move longitudinally on massive rail above the work tableBed is recessed in the floorLoading and unloading of jobs is easyUsed for Planing heavy & large jobsTable and work piece resting on it are stationary and the tool reciprocates

153Edge / plate planerSpecially designed for squaring or beveling the edges of heavy steel plates for pressure vesselsCarriage supporting the tool is moved back and front directionCutting can take place during both directions of carriage travelOperator stands on the platform & operates

154Divided table planerAlso known as Tandem planerPlaner has two tables on the bedTable may be reciprocated together or separatelyEach table reciprocates under different tool headFor continuous production, small work pieces clamped on one table are being machined, another is stationary and can be used for setting up fresh worksUsed for quick & continuous production

155Planing machine - parts

BED

TABLE

CROSS RAIL

COLUMN

TOOL HEADS

Feed Mechanism

155

156Main Parts of Planing machine

1. Bed 2. Table 3. Housing or Column 4. Cross rail 5. Tool heads 6. Driving Mechanism 7. Feed Mechanism

157Constructional details of a planer

TOOL HEADSCROSS RAILTABLECOLUMNBEDCROSS MEMBER

COLUMN

Feed Mechanism

158Parts of planer

159Parts of planer

1601. BedLarge box like castingLength is nearly twice the table lengthConsists guide ways on which table movesHouses the driving mechanism of tableMade of Cast Iron

1612.TableAlso called PlatenLarge rectangular casting mounted on bed waysHolds the work & reciprocates along bed waysTop surface has T slotsWork is clamped on T slots

1623.Housing or Column

Large vertical structures on each side of the bedSupports cross rail on which tool heads are mountedAlso supports the mechanism for operating the tool headsMade of Cast Iron

1634. Cross railA rigid casting mounted horizontally on the columnCan be moved up & down by elevating screwCarries two slides with tool headsTool heads can be moved horizontally on the guide ways of cross rail

1645. Tool headsContains tool posts for holding the toolsTool post (clapper block) is hinged to the headDuring return stroke cutting tool will be liftedTool heads can be swiveled through 60 on either side of its vertical position

165Specifications of a Planer 1. Distance between the two housings

2. Height between Table & cross rail at its uppermost position

3. Maximum length of table travel

4. Number of Speeds & feeds available

166Specifications of a Planer- contd. 5. Power input

6. Floor space required

7. Type of Drive

8. Net weight of the Machine

167Mechanism IntroductionA Planing Machine produces flat surfaces

The Table holding the Work reciprocates

There should be some mechanism to move the Table in reciprocating motion, and

Table to move quick during idle stroke

168Mechanisms to drive the Table (QRM) 1. Open & Cross belt drive

2. Reversible motor drive

3. Hydraulic drive

1691.Open & Cross belt drive Mechanism

Loose PulleyFast Pulley17. Belt shifter leverPulleys on ShaftOpen beltCross beltBelt shifterCounter ShaftLoose PulleysFast Pulleys9,1210,1113 - Bull gear shaft14 - Bull gear Rack18. Trip dog19 - TableChange gears Feed disc

170Open & Cross belt drive MechanismUsed for smaller capacity machines

Table is moved by gears & rack attached under the table

Counter shaft at the top of housing has 2 pulleys

These Pulleys transfer power to main shaft(Driving)

Main shaft drives the table by rack & pinion

171Open & Cross belt drive Mechanism2 Sets of fast & loose pulleys are mounted on driving shaft at one end and pinion is on another endRETURN STROKE:Smaller fast pulley is used for backward motion of table (Quick motion)It is connected by open belt driveThe open belt passes over small fast pulley to get Quick returnThe Cross belt is on loose pulley so it will not drive

172Open & Cross belt drive Mechanism FORWARD STROKE:Bigger fast pulley is driven by cross belt driveIt is used to drive the table during cutting strokeOpen belt is on loose pulleyAt the end of cutting stroke, cross belt is shifted from fast pulley to loose pulleySimultaneously open belt is shifted from loose pulley to fast pulleyThis is achieved by trip dog which operates belt shifting leverThus the direction of movement is automatically reversed

173Rack & Pinion used to move Table

1742. Reversible Motor Drive Mechanism

Electric motor drives the bull gear through gear trains

Motor is coupled to D.C. generator

When motor is started, generator supplies power to reversible motor

175 Reversible Motor Drive MechanismReversible motor causes the planer table to move

At the end of stroke, trip dog operates the switch which reverses the direction of table

Speed of cutting stroke is reduced by regulating the field current of the generator

176Reversible Motor Drive Diagram

ExciterA.C.driving motorGeneratorReversible motorMotor field resistanceMotor field Generator field Reversing switch

1773.Hydraulic Drive of Planer

TABLEOperating CylinderSpeed Control

178Forward Stroke of TableDuring cutting stroke, oil is pumped into LHS of cylinderAs the area is less due to presence of piston rod, less force actsSo the table moves slowly in cutting strokeAt the end of each stroke trip dog operates a leverLever actuates the control valve of circuit

TABLE

179Return Stroke of TableOil is pumped into the Operating cylinderCylinder contains piston & piston rodThe other end of piston rod is connected to the TableDuring return stroke, oil is pumped into RHS of cylinderMore force acts on the piston & it moves quickly

TABLE

180Cycle RepeatedFlow of oil is changed from one side to the other side of cylinder

The length of stroke can be varied by adjusting the distance between trip dogs

181Planer Operations 1.Planing Horizontal Surfaces

2. Planing Vertical Surfaces

3. Planing Angular Surfaces / Dovetails

4. Planing Curved surfaces

5. Planing Slots, key ways & Grooves

182Planing Horizontal SurfacesFix the work properly on the table

Set the required cutting speed

Give required feed of the tool

Give suitable depth of cut for rough cuts

Finishing the job by giving less depth of cut

183

WORKPLANER TABLEPlaning Horizontal Surfaces

TOOLCLAPPER BLOCK

184Planing Vertical SurfacesFix the job on the table firmlyAlign the surface to be machined properlyVertical side is adjusted perpendicular to the tableSwivel the apron away from the jobSwitch on the machine Rotate down feed screw by hand to give down feed

185Planing Vertical Surfaces

PLANER TABLE

WORK

186Planing Angular SurfacesMain angular planing is to make dove tails & V grooves Set the work on the tableSwivel the tool head to the required angle Set apron away from work Give down feed as per requirement

187Planing Angular Surfaces

188Planing Formed SurfacesFix up a square nose tool in tool head

Required form is obtained by feeding the tool simultaneously in both hor. & ver. Directions

Give suitable depth of cut

This can also be done with the aid of a special fixture

189

TOOL

WORK

PLANER TABLE

Planing Formed Surfaces

190Planing Slots & GroovesFix up the job on the table suitably

Fix Slotter tools in tool heads

Give feed using down feed screw

Move the tool by the required amount to get uniform slots / grooves

191Cutting Rack or Splines

PLANER TABLEWORK

Heavier, more rigid costlier machine.Requires more floor area.Work reciprocates horizontally.Tool is stationary during cutting.Heavier cuts and coarse feeds can be employed.Work setting requires much of skill and take longer time.Several tools can be mounted and employed simultaneously, usually four as a maximum facilitating a faster rate of production.Used for machining large size work pieces.

A comparatively lighter and cheaper machine.Requires less floor area.Tool reciprocates horizontallyWork is stationary during cutting.Very heavy cuts and coarse feeds cannot be employed.Clamping of work is simple and easy.

Usually one tool is used on a shaper.

Used for machining small size work piece comparativelyComparison between planer and shaperShaperPlaner