shaper slotter plannerWhat is a shaper ? • A Machine which produces flat surfaces • A Ram holding the Tool reciprocates • Work is fed perpendicular to the tool working principle • 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 • The tool line eventually reaches position C D • Combination of two movements results in the flat plane ABCD being machined Classification of shapers Basic types: • Horizontal Shaper • Vertical Shaper • Traveling head Shaper 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. 1. Acc. to Cutting Stroke action a) Push Type Shaper b) Draw Type Shaper 2. Acc. to the Table Design: a) Standard Shaper b) Universal Shaper 3. Acc. to Driving Mechanism: a) Crank type b) Geared type c) Hydraulic Shaper Push type shaper • Metal 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 Draw type shaper • Metal is removed when the tool is drawn towards the colu mn • Allows heavier cuts to be made • Less vibration during cutting Standard shaper Work Table can be moved 1.Vertically & 2. Horizontally Universal shaper Table can be moved 1. Horizontally 2. Vertically 3. Swivelled &4. Tilted This is mostly used in Tool Rooms Crank type shaper: • Driving mechanism is by crank & 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. • Construction of Shaper Main parts of a shaping machine 1. BASE 5. CROSS RAIL 2. COLUMN 6. SADDLE 3. RAM 7. TOOL HEAD 4. TABLE 8. CLAPPER BOX 1. Base • Bottom most part • Supports other parts of the machine • Acts as a reservoir of lubricating oil • Made of Cast Iron 2. Column • Vertically mounted on the base • Houses Driving Mechanism of Ram • Has guide ways on which Ram slides • Made of Cast Iron 3. Ram • The main moving part of a Shaper • It carries Tool Head • Connected to Driving Mechanism 4.Table • A box like casting with T-slots on its top • Shaper vice is fitted in the T-slots • Work is fixed in the vice 5. Cross rail • Used to move the Table Up & Down • Upward movement is controlled by an Elevating Screw • Side movement is controlled by lead screw 6. Saddle • It is mounted on cross rail • It supports the Table • Moves across the cross rail left to right • Movement obtained by a cross feed screw 7. Tool head • It is attached to the front end of Ram • Carries Clapper box & Tool post on it • Stroke length can be changed by varying the radius AE • On entering the cut the highest pressure on the tool and the slowest speed is available. • Ram returns at high speed as the crank rotates from X to Y through T. So t hat the ram moves faster during return stroke • Thus minimizing the (idle time) Quick Return time. the time for cutting is more than the idle time. • The shaper drive system incorporates quick return mechanism.length of Stroke of Ram • Type of Drive • Power input • Floor Space required • Weight of the Machine • Cutting to Return Stroke ratio • Feed Shaper Drive Mechanisms • Since return stroke does no cutting the ram should move faster during return stroke. • During cutting stroke point C travels from Y to X through Z. Shaper Driving Mechanisms • Whitworth quick return mechanism • Slotted link quick return mechanism • Hydraulic quick return mechanism Whitworth Quick Return Mechanism • Crank BC revolves at a uniform speed.• Can be swiveled at any angle on either side 8. . Clapper box • It is hinged to the tool head • It houses clapper block • Swings outward in return stroke • Tool post mounted on clapper block Specifications of Shaping Machine • Max. • Then:Time for cutting stroke 360 – Ø Time for return stroke Ø • Since Ø is smaller than 360 – Ø. • So Return stroke is completed in a shorter time. • So sliding block 12 also rotates on the crank pin circle. Ratio between cutting time & return time. • When it is at PN. • Electric motor drives pinion (1) • Pinion (1) drives the bull gear(14) • A Radial slide (16) is bolted at the centre of bull gear. • Simultaneously crankpin will move up & down in the slot of the slotted link 9. • Forward cutting stroke takes place through the angle C1 K C2 • Return stroke takes place through the angle C2 L C1 of the crank. • It is evident that angle C2 K C1 is greater than C2 L C1 • Angular velocity of crank pin is constant. • As the crank pin11 moves. • Thus the rotary motion of the bull gear is converted to reciprocating motion of the ram. • This rocking movement is communicated to the ram. slotted link 9 gets rocking movement. • Cutting time : Return stroke = Angle C1KC2 : Angle C2LC1 • Cutting time : Return time ratio • usually varies bet 2 : 1. • When the link is in the position PM. • Therefore it is known as quick return motion. ram is at extreme forward position • PM&PN are tangents drawn to the crank pin circle. ram will be at the extreme backward position.• On entering the cut the maximum pressure is holding the ram down in its slides Crank & Slotted Link QRM • Crank 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). crank pin 11 rotates. • Practical limit is 3 : 2 Hydraulic Quick Return Motion Mechanism • The Ram with cutting tool has to move slowly in cutting stroke • Ram to return quickly in idle stroke • The first 2 methods are discussed already • The 3rd method is by Hydraulic Mechanism . • Radial slide carries a sliding block(12) & a crank pin (11) • As the bull gear 14 rotates. e. Machine is not overloaded Shaper Operations • Machining Horizontal Surfaces • Machining Vertical Surfaces • Machining Angular Surfaces • Cutting Slots. Grooves & Key ways • Machining irregular surfaces • Machining Splines / Cutting Gears Steps for Machining • Work 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 work • The approach & over run should be 10 & 5 mm respectively. pressure increases • Increase in pressure causes Speed of ram to increase in Return stroke Advantages of Hydraulic Shaper • Cutting tool works uniformly during cutting stroke • Reverse stroke is obtained without any shock • More no.• If the Quick Return Motion is obtained by hydraulic means in a Shaper • Then such a Shaping Machine is Known as HYDRAULIC SHAPER WORKING – Forward Stroke • Oil is pumped to Right side of Cylinder • Piston moves Left Hand Side • Ram moves Forward Stroke • Shaper dog hits the reversing lever • Reversing lever alters valve position • Oil is now pumped to Left side of Piston • Piston moves Right Side • Ram performs Return Stroke • Oil on the Right side of Piston goes to reservoir • At the end of Return stroke another trip dog hits reversing lever • Reversing lever changes direction of stroke of Piston • Thus the Cycle is repeated QRM is obtained • Due to the difference in stroke volume • Volume on Left side of piston is small due to presence of piston rod • Right side volume is larger ( absence of piston rod) • Pump pumps same amount of oil both sides • As volume is small on Left side. of cutting speeds are obtained • Good control on cutting speed • Relief valve ensures safety i. • 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 Machining Horizontal Surfaces • Fix the work properly on the table • Adjust the length of stroke . dove tail etc.25 mm Machining Angular Surfaces • Angular shaping is carried out to machine inclined surfaces.• Set the required cutting speed • Give required feed of the table • Fix an appropriate tool in the tool head • Give suitable depth of cut for rough cuts • Finishing the job by giving less depth of cut Machining Vertical Surfaces • Fix up the job on the table firmly • Align the surface to be machined properly • Fix up a side cutting tool in the tool head • Set the vertical slide exactly at zero • Swivel the apron away from the job • Switch on the machine • Rotate down feed screw by hand to give down feed • Feed in about 0. bevelled. • Using a Swivel Vice • Using T bolts & Clamps • Using Angle plate & C Clamps Slotting machine • A Machine which produces flat surfaces • A Ram holding the Tool reciprocates • Ram reciprocates in verticle direction • Work is fed perpendicular to the tool . • Set the work on the table • Swivel 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 Cutting Rack or Splines • Fix up a square nose tool in tool head • Adjust the length & position of stroke • Reduce the cutting speed • Give suitable depth of cut • Feed the work properly to get equal splines Cutting Key ways • Fix up the job between two centres • Cut first spline similar to a key way • Move / Rotate work by the required amount • Use index plate for this purpose Machining irregular surfaces • Fix up a forming tool in tool post • Give cross feed in conjunction with down feed • Swivel the apron suitably according to the contour required Clamping the Work on a Shaper Work should be properly & firmly fixed on the Shaper table Work is fixed on the table by 3 methods.. 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 Difference between vertical shaper and Slotter • in verticle shaper the tool holding ram can tilt by about 50 with respect to verticle axis • In slotter ram cannot tilt at all.Slotter . Ram 7. Base • Bottom most part • Supports other parts of the machine • Acts as a reservoir of lubricating oil • Made of Cast Iron Base • Rigidly built to take up cutting forces • Top of bed is accurately finished • Guide ways are provided for saddle • Guide ways are perpendicular to column face . Cross slide 2. Saddle 3. • heavy and rigid machine • Ram driven by rack and spiral pinion mechanism • used for machining large castings and forgings Precision tool room slotter: • Used for tool room work. Table 1. Base 5. Column 6.working principle • 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 • The tool line eventually reaches position C D • Combination of two movements results in the flat plane ABCD being machined • Work is supported on a rotary table. Tool head 4. • Table can have longitudinal and rotary movements • Straight and rotary cuts can be produced. CLASSIFICATION According to design and purpose the slotters are classified into two types Puncher Slotter Precision tool room Slotter Puncher slotter: • Intended for removing large amount of metal from heavy works. • In all other aspects verticle shaper and slotter are similar Main parts of a slotter 1. Column • Vertically mounted on the base • Houses Driving Mechanism of Ram • Has guide ways on which Ram slides • Made of Cast Iron • Also houses feeding mechanism Ram • Reciprocating vertically up and down of a slotter • Mounted on guide ways of column • It carries Tool Head / cutting tool • Connected to Driving Mechanism • An arrangement is provided on the body of ram to change length of stroke Table • It holds the work piece. • Type of Drive • Maximum table travel. • A circular casting with T-slots on its top • Movement of table can be linear or rotary • Table is graduated in degrees so indexing can be done • Slotter vice may be fitted in the T-slots • Work may be fixed in the vice • Operated manually or by power Saddle • It is mounted on guide ways of bed • It can be moved towards or away from bed • Using saddle longitudinal feed is given • Top is accurately finished to provide guide ways for cross slide • These guide ways are perpendicular to the guide on the base • Operated either manually or by power Cross slide • Circular 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 Tool 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 Specifications of Slotting machine • Max. length of Ram Stroke • Diameter of work table in mm. • Power input • Floor Space required Specifications Contd. . cross and c. Whitworth Q. Slotter driving mechanism • A Slotting machine produces flat surfaces • The Ram holding the Tool reciprocates vertically up and down • Cuts the material only in down stroke • There should be some mechanism to move the ram in reciprocating motion • It is called as slotter driving mechanism • The mechanism commonly used is slotted disc mechanism Quick return mechanism (QRM) • A Mechanism makes the ram to move slowly during cutting stroke. • Ratchet is moved by small amount in one direction only with the help of a connecting rod. of feeds available • Table feed. lever.R. Hydraulic drive Mechanism The mechanisms for QRM in slotter are similar to QRM in shaper Feed in Slotter • In Slotter feed is given by table • Feed movement is intermittent • Feed is given at the beginning of the cutting stroke • Feed may be given either manually or by power • Table will have three types of feed movements a. • The roller moves in the cam groove cut on the face of the bull gear of slotting machine. of speeds available • No. Mechanism 2. longitudinal / rotary feed screws has the ratchet mounted on it. • During return stroke ram moves at a faster rate. • To reduce the idle time. . • The mechanism adopted is known as QRM Methods to obtain Q. circular feeds. Types of feed in Slotter Longitudinal feed: • Table is fed perpendicular to the column • Table moves towards or away from the column Cross feed: • Table is fed parallel to the face of the column Circular feed: • table is rotated with respect to verticle axis Feed mechanism of a Slotter • Uses a ratchet and pawl mechanism • Feed shaft engaged with cross.R.It Should return quickly .• Amount of longitudinal travel in mm • No. longitudinal b. in slotter .M. Variable speed reversible motor drive mechanism 3.M. Machining Circular Surfaces 3. Machining flat surfaces 2. • 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 Machining Flat Surfaces • Fix the work properly on the table • Adjust the length of stroke • Set the required cutting speed • Give required feed of the table • Tool is held in the tool head of ram • Ram reciprocates up and down • Feed has to be given at the beginning of cutting stroke • Both internal and external surfaces can be machined • Give suitable depth of cut for rough cuts • Finishing the job by giving less depth of cut Machining circular surfaces • Tool is set radially on the work • Work piece is placed centrally on the rotary table • Feed is given by the rotary table feed screw • Feed screw rotates the table through an arc • Adjust the length of stroke • Set the required cutting speed • Finishing the job by giving less depth of cut Machining internal surfaces • Fix up a tool in tool post • Cross.Operations on slotter 1. longitudinal and rotary feed are combined • Any contoured surface can be machined • Mostly done manually • Good skill is required from operator Machining grooves or key ways • Slotter is specially intended for cutting internal grooves • External or internal gar teeth can be machined • Fix up the job between two centers • Cut first a key way • Move / Rotate work by the required amount • Indexing can be done by using graduations on rotary table Cutting Key ways . Machining grooves or key ways Setup for Machining • Work 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 work • The approach & over run should be 10 & 5 mm respectively. Machining internal surfaces 4. Using T bolts & Clamps 3. Edge Planer or Plate Planer 5. that con not be accommodate on shapers • The tool is stationary but the work moves Planer . Using a Swivel Vice 2. Using Angle plate & C Clamps What 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. Pit type Planer 4. Divided Table Planer Double housing planer: • It is the Standard model & most widely used • Very heavy and robust • Has a bed and two vertical housings are fixed • Table moves along the guide ways of the bed • Housing supports cross rail & tool heads.working principle • The table on which work is clamped is imparted a reciprocating movement • Cutting takes place during the forward stroke of table • During return stroke the cutting tool is slightly lifted • Tool is fed for each forward stroke • Table is driven by an electric motor • Length of table stroke can be adjusted • Speed of return stroke is also regulated Classification of planers Double housing Planer 2. 1.• Fix up the job between two centres • Cut first spline similar to a key way • Move / Rotate work by the required amount • Use index plate for this purpose Work holding devices Work should be properly & firmly fixed on the Slotter table Work is fixed on the table by 3 methods. • Cross rail carries two tool heads • Tool head carries tools Open side planer • It has only one supporting column (housing) • Area larger than the table can be planed • Cross rail is mounted as a Cantilever • Tool holders ( max.3) are mounted on Cross rail • Stroke length of bed is controled by adjustable dogs PIT Planer • Columns and cross rail carrying tool head move longitudinally on massive rail above . Open side Planer 3. Bed • Large box like casting • Length is nearly twice the table length • Consists guide ways on which table moves • Houses the driving mechanism of table • Made of Cast Iron 2.Table • Also called Platen • Large rectangular casting mounted on bed ways • Holds the work & reciprocates along bed ways • Top surface has T slots • Work is clamped on T slots 3. Cross rail 5. Bed 2. Housing or Column 4. Tool heads 6.Housing or Column • Large vertical structures on each side of the bed • Supports cross rail on which tool heads are mounted • Also supports the mechanism for operating the tool heads • Made of Cast Iron 4. another is stationary and can be used for setting up fresh works • Used for quick & continuous production Main Parts of Planing machine 1. Feed Mechanism 1. Driving Mechanism 7. Cross rail • A rigid casting mounted horizontally on the column .the work table • Bed is recessed in the floor • Loading and unloading of jobs is easy • Used for Planing heavy & large jobs • Table and work piece resting on it are stationary and the tool reciprocates Edge / plate planer • Specially designed for squaring or beveling the edges of heavy steel plates for pressure vessels • Carriage supporting the tool is moved back and front direction • Cutting can take place during both directions of carriage travel • Operator stands on the platform & operates Divided table planer • Also known as Tandem planer • Planer has two tables on the bed • Table may be reciprocated together or separately • Each table reciprocates under different tool head • For continuous production. small work pieces clamped on one table are being machined. Table 3. C. generator . Reversible motor drive 3. Floor space required 7. Maximum length of table travel 4. and • Table to move quick during idle stroke Mechanisms to drive the Table (QRM) . Number of Speeds & feeds available 5. Hydraulic drive Open & Cross belt drive Mechanism • Used for smaller capacity machines • Table is moved by gears & rack attached under the table • Counter shaft at the top of housing has 2 pulleys • Pulleys transfer power to main shaft • Main shaft drives the table by rack & pinion • 2 Sets of fast & loose pulleys are mounted on driving shaft • Smaller fast pulley is used for backward motion of table (Quick motion) • It is connected by open belt drive • Bigger fast pulley is driven by cross belt drive • It is used to drive the table during forward stroke • At the end of cutting stroke. Distance between the two housings 2. Reversible Motor Drive Mechanism • Electric motor drives the bull gear through gear trains • Motor is coupled to D. Power input 6. Open & Cross belt drive 2.• Can be moved up & down by elevating screw • Carries two slides with tool heads • Tool heads can be moved horizontally on the guide ways of cross rail 5. Tool heads • Contains tool posts for holding the tools • Tool post (clapper block) is hinged to the head • During return stroke cutting tool will be lifted • Tool heads can be swiveled through 60º on either side of its vertical position Specifications of a Planer . Net weight of the Machine Mechanisms used to drive the table • A Planing Machine produces flat surfaces • The Table holding the Work reciprocates • There should be some mechanism to move the Table in reciprocating motion. cross belt is shifted from fast pulley to loose pulley • Simultaneously open belt is shifted from loose pulley to fast pulley • This is achieved by trip dog which operates belt shifting lever • Thus the direction of movement is automatically reversed 2. Height between Table & cross rail at its uppermost position 3. Type of Drive 8. Hydraulic Drive of Planer Forward Stroke of Table • During cutting stroke. Planing Angular Surfaces / Dovetails 4. Planing Vertical Surfaces 3. generator supplies power to reversible motor • Reversible 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 3. oil is pumped into RHS of cylinder • More force acts on the piston & it moves quickly Planer Operations 1. . Planing Slots & Grooves Planing Horizontal Surfaces • Fix 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 Planing Vertical Surfaces • Fix the job on the table firmly • Align the surface to be machined properly • Vertical slide is adjusted perpendicular to the table • Swivel the apron away from the job • Switch on the machine • Rotate down feed screw by hand to give down feed Planing Angular Surfaces • Main angular planing is to make dove tails & V grooves • Set the work on the table • Swivel the tool head to the required angle • Set apron away from work • Give down feed as per requirement Planing Formed Surfaces • Fix up a square nose tool in tool head • Required form is obtained by feeding the tool simultaneously in both hor.• When motor is started. & ver. less force acts • So the table moves slowly in cutting stroke • At the end of each stroke trip dog operates a lever • Lever actuates the control valve of circuit Return Stroke of Table • Oil is pumped into the Operating cylinder • Cylinder contains piston & piston rod • The other end of piston rod is connected to the Table • During return stroke. oil is pumped into LHS of cylinder • As the area is less due to presence of piston rod. Planing Curved surfaces 5.Planing Horizontal Surfaces 2. • Both internal and external surfaces can be machined • But limited to removal of 6mm stock or less BROACH • Tool used in broaching • Broach is a multi-teeth cutter produced to close tolerances. semi finishing teeth. namely roughly teeth. is rough.Directions • Give suitable depth of cut • This can also be done with the aid of a special fixture Planing Slots & Grooves • Fix 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 broach BROACHING OPERATION • A method of metal removal with a special tool called Broach. • Available in different shapes and sizes • For irregular shapes one broach for one contour or shape has to be developed • High speed steel is the most widely used material for producing broach. • Cutting tool called broach has three types of teeth. semi finish. finish teeth. some of them are According to type of operation i) internal broach ii) external broach According to method of operation i) push broach ii) pull broach According to type of construction i) solid broach ii) built-up broach iii) inserted tooth broach iv) progressive cut broach According to function . • It has successively higher cutting edges along length • It has three types of teeth. finishing teeth • Broach can be pulled or pushed in a fixed path • Surfaces machined may be flat or contoured can be produced in a single pass or stroke of broach • Both internal and external surfaces can be machined • But limited to removal of 6 mm stock or less BROACHING OPERATION • Surfaces machined may be flat or contoured can be produced in a work piece by a single pass or stroke of broach. • Carbide tools are also used for machining steel castings CLASSIFICATION OF BROACHES Broaches may be classified on different criteria. i) surface broach ii) key way broach iii) round hole broach iv) Spiral broach PUSH BROACH • Designed to be pushed through a stationary work piece • It has tendency to bend under compressive load • It is short and stocky • Fewer teeth on broach • Less stock can be removed for each pass • So production time will be more PULL BROACH • Designed to pull through a stationary work piece • Tool is in tension during cutting • Pull broach is long and slender • It has large number of teeth • More stock can be removed • Production time will be less BROACHING METHODS According to method of operation the broaching may be classified as • pull broaching • push broaching • surface broaching • continuous broaching PULL BROACHING • Work is held stationary • Broach is held in a special head • Broach is pulled over or through the work • Mostly used for internal broaching • Surface broaching can also be done PUSH BROACHING • Work is held stationary • Broach is held in a special head • Broach is pushed over or through the work • Mostly used for i) sizing already drilled holes ii) cutting key ways • Broach is operated by i) manually or ii) Hydraulic arbor press • less metal is removed SURFACE BROACHING • Work is held in a fixture and tool in tool head • Either work or broach moves across each other • Tools must be specially designed for each work piece • Many irregular and intricate shapes can be broached . • Produces excellent surface finish • Time required will be very low when compared to other machining processes. Circular • Suitable for producing similar work pieces • Suitable for mass production • Suitable for small size work pieces only BROACHING MACHINES • Simplest of all machine tools • Have less components • Broaching machines consist of : work holding fixture broaching tool drive mechanism suitable supporting frame • Most machines are hydraulically operated • Has smooth and uniform cutting action • Used for low or high production quantities. Straight horizontal or ii. CONTINUOUS BROACHING • Broach tool is held stationary • Work pieces are moved continuously • Path of work piece movement may be i. CLASSIFICATION OF BROACHING MACHINES Broaching machines are mainly classified as • Horizontal broaching machines (push or pull type) • Vertical broaching machines • Special design continuous broaching machine • Rotary table continuous broaching machine • horizontal continuous broaching machine HORIZONTAL BROACHING MACHINE Main parts of the broaching machine are Bed Housing Drive mechanism Broach pilot Fixture BED: • Bottom most part • Supports other parts of the machine • Made of Cast Iron HOUSING: houses the driving mechanism houes the pulling head DRIVE MECHANISM drives the pulling head cutting stroke speed is less return stroke speed is more . • Broach pilot holds the broach rigidly • Fixture holds the work piece rigidly HORIZONTAL BROACHING MACHINE • Both surface and internal broaching can be done • Broach is securely held in a pulling head • In surface broaching broach is pulled over the surface • For internal broaching broach is pulled through work • Mainly used for internal broaching • Operated at cutting speed of 3 to 5 m/min • Speed of return stroke is 30 m/min • Hydraulic drive is used for pulling head • Operated at infinitely variable range of cutting speeds • Hydraulic cylinder is housed on right side of the machine • Long broaches are easily handled • heavy work pieces are easily handled • occupies more space than vertical machine Uses It is used to machine • Keyways • Splines • Slots • Round holes • Other internal shapes These are further classified as • Surface broaching machines • internal broaching machines VERTICAL BROACHING MACHINE • it may either push type or pull type • pull type is popular • Main parts of vertical broaching machines are Base Column Ram and broach Fixture and table Drive mechanism • Three models are available in vertical type pull up pull down push down • Pull up model is most popular • Broach is securely held in ram • Occupy less floor space • Modern vertical machines are available with • Hydraulic drive • Electro-mechanical drive • Hydraulic drive machines cost less . broaching machine with specification 1000-10 means • Machine has 1000 mm stroke length and • 10 tones broach driving force Other parameters to be specified are .e..• Require plat form or pit for the operator • Convenient to pass work from one machine to other • Employed in multiple operations • Two rams will be provided on some machines • Such machines are called duplex head machines DUPLEX HEAD BROACHING MACHINE • Machine with two heads • Simultaneously two surfaces can be machined • Mostly push type machines • Commonly employed for surface broaching • Rate of production is high CONTINUOUS BROACHING MACHINES • used for mass production of small parts • they are of two types – Rotary continuous broaching machine – Horizontal continuous broaching machine • In both machines – Broach is stationary – Work pieces move across broach ROTARY CONTINUOUS BROACHING MACHINES • Work pieces are loaded on the table • Table rotates continuously • During broaching broach is stationary • Work pieces are held in fixtures • Work pieces come into contact with broach during table rotation • Loading and unloading done on the table • It is a surface machining operation • Heavy production rate • • Chain carries work holding fixtures • Work pieces are placed in fixtures • Broach is held stationary • When chain rotates the work pieces move against stationary broach • It is a surface broaching operation • Heavy production rate SPECIFICATION OF BROACHING MACHINE • Main specification – Length of stroke in mm. – Force that can be applied to broach in tones i. 50 to 200 Rake angle: it corresponds to rake angle of lathe tool its value increases as ductility increases ADVANTAGES OF BROACHING • rate of production is high • Less skilled worker can be employed • High accuracy can be obtained • High surface finish can be obtained • Rough and finish cut both are completed in one pass • both internal and external surfaces can be machined • Any form that can be reproduced on broach can be machined • Cutting fluid may be readily applied • Life of broach tool is high • Cutting temperature and tool wear is low • Cutting force acts in clamping direction • Process can be semi or fully automised LIMITATIONS OF BROACHING • High tool cost • Economical only for mass production .P of the motor BROACHING OPERATIONS Broaching is applied for • various internal and external surfaces • round and irregular shaped holes of 6 to 100 mm diameter • Flat and contoured surfaces Most operations are completed with one pass of the broach In all broaching operations • Work is held in a fixture • Tool is held in tool head (pulling or pushing head) • Either work or tool move across each other • Various broaching operations are as shown in following slides Nomenclature of broach tooth Pitch: linear distance between cutting edge of one tooth and corresponding edge on next tooth Land: top portion of tool ground to provide a slight clearance Back off: it is the clearance angle of broach its value vary from 0.• Broaching speed • Return speed • Machine horse power • Floor space required • H. . Coolants and Lubricants About Me BIG NOTES View my complete profile .• Sharpening is difficult and expensive • Not suitable for very large work pieces • Surfaces should not have obstructions • Cannot remove large amount of stock • Very light and delicate jobs cannot be broached Posted by BIG NOTES at 4:31 AM 1 comment: gexhouse2 said. A Machine which produces flat surfaces A Ram holding the Tool reciprocates Work is fed perpendicular to the tool. 2013 at 12:48 AM Post a Comment Newer PostOlder PostHome Subscribe to: Post Comments (Atom) o Blog Archive ▼ 2008 (4) ▼ July (4) lathes&lathe works shper slotter planner METROLOGY Cutting fluids. Corrugated Carton Box Maker Rottery Slotter Machine July 8..