Unit 3

2 marks

What is shaper?The machine which is having a reciprocating type of machine tool with single point cutting tool used to produce flat surface called as shaper.

List any four important parts of a shaper.

Table

Tool head

Ram

Cross rail

Define one pass of the cutting tool.

The combination of one forward and one return stroke is called one pass of cutting tool.

No. of passes = Stroke to be removed

Depth of cut

Define cutting ratio of a shaper.

The ratio of cutting stroke time to the return stroke time is called the cutting ratio of a shaper.

m=cutting stroke time

return stroke time

List any two types of quick return mechanisms.

Hydraulic drive mechanism

Crank and slotted lever mechanism

How is the feed and the depth of cut given to the shaper?

Feed is given by rotating the down feed screws of total head. Depth of cut is given by rotating by raising or elevating the table.

State the various types of flat surface produced on a shaper

Horizontal surface

Vertical surface

Inclined surfaceWhat are the various types of shaper according to various conditions?

1. According to the type of driving mechanism

I. Crank drive type

II. Whit worth driving mechanism type

III. Hydraulic drive type

2. According to the position of ram

I. Horizontal shaper

II. Vertical shaper

III. Travelling head shaper

3. According to table design

I. Standard or plane shaper

II. Universal shaper

4. according to the type of cutting stroke

I. Push out type

II. Draw cut type

What are the other types of shaper?

Standard or plane shaper

Universal shaper

Draw cut shaper

Compare hydraulic shaper and mechanical shaper.

S.NOHydraulic shaperMechanical shaper

1.Smooth cutting operationRough and noisy cutting operation

2.Change of cutting speed is easyChange of cutting speed is difficult

3.Higher cutting to return ratio can be obtainedLower cutting to return ratio

4.Stroke length can be easily adjusted without stopping the machineChange of stroke length is not possible without stopping the machine

Mention any four shaper specifications.

Maximum length of stroke

Type of driving mechanisms

Power of the motor

Speed and feed available

State the type of mechanism followed on a shaper and state how it works.

Rack and pinion mechanism is used. The rotary motion of electric drive is converted into reciprocating motion of the ram by using gears and slotted link.What are the precautions to be carried out before machining any surface?

Position adjustment

Stroke length adjustment

State any two reasons for making the stroke length greater than work length.

If the crank pin is adjusted in such a way from the center of the bull gear, the rocker arm reciprocates for a larger distance. So, the stroke length is increased.

The stroke should always be greater than the working length i.e. some amount of approach and over run should be provided to the tool movement.

What are the types of feed?

Hand feed

Automatic feed

What are the various types of tool?The tools are classified as

1. According to the shape

I. Straight tool

II. Cranked tool

III. Goose necked tool

2. According to the direction of cutting

I. Left hand tool

II. Right hand tool

3. According to the finish required

I. Roughing tool

II. Finishing tool

4. According to the type of operation

I. Down cutting toolII. Parting off tool

III. Squaring tool

IV. Side recessing tool

5. According to the shape of cutting edge

I. Round nose tool

II. Square nose toolWrite down any four operations performed by a shaper.

Machining horizontal surfaces

Machining vertical surfaces

Machining inclined surfaces

Machining irregular surfaces

How are the feed and the depth of cut given to the shaper while machining irregular surfaces?

For machining irregular surfaces, a round nose tool is set on the tool head. By giving both cross feed and vertical feed at the same time, the irregular shape is obtained. The cross feed is given through the table and the vertical feed is given through the tool head. The apron is fitted to some angle from the machining surface to avoid rubbing of the tool on the work during return stroke.

Define feed and depth of the cut.

Feed: The relative movement of the tool with respect to work piece axis is known as feed.

Depth of cut: Amount of metal removed in one revolution or in cut is known as depth of cut.

Define the metal removal rate.

The volume of metal removed per unit time.

mmr (or) w = f t L s

How does a planer differ from a shaper?

In planer: The work reciprocates while the tool is stationary.

In shaper: The tool reciprocates while the work is stationary.Under what conditions planning operations would be preferred over other machining operations like milling, broaching, shaping etc.?In planer, the work piece mounted on the table reciprocates but the tool is stationary. A single point cutting tool is used for machining the work surface this tool is always fitted vertically the tool holder which moves on a cross-rail while feeding. Planer is mainly used for machining large and heavy work pieces. The machine surface maybe horizontal ,vertical or inclined surfaces

Mention the operations performed by a planer.

Planning horizontal surface

Planning of an angle

Planning vertical surface

Planning curved surfaceList the various types of planers.

1. Double hosing planer

2. Open side planer

3. Pit planer

4. Edge planer

5. Divided table planer

What the main difference in open side planer?

The only difference in this type is only one vertical column provided one side of the bed and other side is left free.

What is the main differtence made in divided table planer?

The working principle is similar to that of a standard planer. But it has two reciprocating tables.

Mention any four specifications of planer?

1. Maximum length of the table

2. Total weight of the planer

3. Power of the motor

4. Range of speeds and feed available

5. Types of drives required

What is the function of clapper block in a planer?

During cutting stroke,the tool block fits inside the clapper block rigidly.during the return stroke ,the tool block lifts out off the clpapper block to avoid rubbing of the tool on the job.

What are the various types of quick return mechanism?

1. Open and cross belt drive

2. Electric drive

3. Hydraulic drive

State the difference between vertical shapper and a slotter.s.noVertical shapperSlotter

1Vertical shapper generally fitted with rotary table to machine curved surfaces.The slides are fitted

2Rotary table along with tools will move.Slides will move to perform slotting.

3Vertical shapper is not fixed in vertical planeslotter is fixed in vertical plane.

List the various quick returm motion mechanism used in slotter.1. Whitworth quick return mechanism.

2. Variable speed reversible electric motor drive.

3. Hydraulic motor drive.

Mention the different feeds available in slotter.1. Longitudinal feed.

2. Cross feed.

3. Circular feed.

What are the operations that can be performed on a slotter?

1. Machining flat surface.,

2. Machining grooves,slotts,keyways.

3. Machining cylindrical surfaces.

4. Machining irregular surfaces.

Define milling process. Milling is the process of removi ng metal by feeding the work past against a rotating multipoint cutter.

What are the specification of milling machine?

1. The table length and the width.

2. Maximun longitudinal cross and vertical travel of the table.

3. The number of spindle speeds and feeds.

4. Power of driving motor.

Classify milling machine.1. Column and knee type

a) Plain milling machine.

b) Vertical milling machine.

c) Universal milling machine.

d) Ram-type milling machine.

e) omniversal milling machine.

2. Bed-type milling machine

a) Simplex milling machine.

b) Duplex milling machine.

c) Triplex milling machine.

3. Plano-type milling machine.

4. Special purpose milling machine

a) Rotary table milling machine.

b) Drum milling machine.

c) Profile milling machine.

Mention the various movements of milling machine table?

1. Vertical movement -throught the knee.

2. Cross slide movement -throught the saddle.

3. Longitudinal movement of the table.

What are the different ways for machining workpiece in plano-milling?

1. By moving the table, cutters rotating in position.

2. By keeping the table stationary and feeding the cutter by moving the milling heads.

3. By moving the table and the milling heads simultaniously.

4. By keeping the table stationary,moving the cross-rail downward and the side cutters up and down.

What are the various type of special purpose milling machine?

1. Rotary table or continuous milling machine.

2. Drum type milling machine.

3. Profile or contour milling machine.

What are the common work holding devices used on the milling machines?

1. V blocks.

2. Machine vice.

3. Milling fixture.

4. Dividing heads.

What are the cutter holding devices?

1. Arbors.

2. Adaptors.

3. Collets.

What are the two types of arbors?

1. Standard arbor.

2. Stub arbor.

Lists the various types of milling attachments.1. Vertical milling attachment.

2. Universal milling attachment.

3. High speed milling attachment.

4. Rotary attachment.

5. Slotting attachment.

Write any ten nomenclature of a plain milling cutter?

Body of cutter,cutting edge ,face,fillet,gash,lead,land,outside diameter,root diameter,cutter angles.

What is shell mill?

A shell mill is a large type of face or end mill that mount onto an arbor,rather than having an integral shank,typically there is a hollow or recess in the centre of the shell mill for mounting hardware onto a separate arbor.

What is meant by up-milling and down milling?

In up milling ,cutter rotates opposite to the direction of feed of the workpiece whereas in down milling,the cutter rotates in the same direction of travel of the workpiece.

What are the difference between up milling and down milling?

s.noEvent of operationUp millingDown milling

1Direction of travelCutter rotates against the direction of travel of workpiece.Cutter rotates in the same direction of travel of workpiece

2Chip thicknessMinimum at the beginning of cut greech max when the cut terminates.maximum at the beginning of cut greeches min at terminates.

3Cutting forceIncresing from 0 to max per toothDecreasing from max to 0 per tooth.

List out the various milling operation.1. Plain or slab milling.

2. Face milling.

3. Angular milling.

4. Straddle milling.

5. Gang milling.

6. Form milling.

7. End milling.

8. T-slot milling.

What is thread milling?

A thread milling has no chamfer. The mill is inserted into the hole along axis of spindle,deep enough to produce full thread depth required.

What is meant by the term indexing?

Indexing is the process of dividing the pheriphery of a job into the equal number of division.

Write down the rule for gear ratio in differential indexing?

Rule for gear ratio in differential indexing

Gear ratio =( (A-N)*40 ) / (A)

A= selected no which can be indexed by plain indexing and approximately equal to N.

N= required no. of divisions to be indexed.

What is the combination of a two movements in differential indexing?

When the indwex plate rotates in the same direction of the crank,the resulting movement of the crank will increase .when the index plate rotates in opposite direction of the crank, the resulting actual movement is decreased.

Classify drilling machine.1. Portable drilling machine .

2. Sensitive drilling machine.

a. Bench type.

b. Floor type.

3. Upright drilling machine.

a. Round column type or pillar type.

b. Box column type or square section type.

4. Radial drilling machine.

a. Plain type.

b. Semi-universal type.

c. Universal type.

5. Gang drilling machine.

6. Multiple spindle drilling machine.

7. Automatic drilling machine.

8. Deep hole drilling machine.

What are the main components of a radial drilling machine?

1. Base.

2. Coulmn.

3. Radial arm .

4. Drill head.

5. Spindle head and feed mechanism.

What are the various type of drilling machine?

a. Plain type.

b. Semi-universal type.

c. Universal type.

How do you specify radial drilling machine?

1. Maximum size of the drill in mm that the machine can operate.

2. Table size of maximum dimension of a job can mount on a table in sq.m.

3. Maximum spindle travel in mm.

4. No. of spindle speed and range of spindle speed in rpm.

Write down any four operation that can be performed in a drilling machine?

1. Drilling.

2. Counter sinking.

3. Tapping.

4. Trepanning.

What is meant by sensitive hand feed?

In the drilling machines , manual sensing of the hand does feeding of the tool towards the work piece is called sensitive hand feed.

Calculate the tap drill size to cut an internal thread for bolt of outside diameter of 10mm,pitch = 1.5mm and depth of the thread is 0.61 pitch.?

Ans :

Drill size = tap size 2 x depth of thread.

Depth of threads = 0.61 x 1.5 = 0.915mm.

So ,drill size = 10 2 x 0.915 = 8.17mm.

How does the reamer tool differ from drilling tool?

A reamer is a multitooth cutter which rotates and moves linearly into an already existing hole.

What do u know about straight fluted drill and fluted drill?

The reamer which helical flutes provides smooth shear cutting action and provides better surface finish. The pitch of flutes is made uneven to reduce vibration.Write the difference between drilling and taping?

Drilling is a process of producing a hole on the workpiece by using a rotating cutter called drill.

Diifferent shapes of holes can be made.

Taping is a procesas used for making internal threads in amachine components by a tool called tap. Internel thread can be cutt in exiting drilled holes.State any four specification of horizontal boring machine.

Type of machine- floor , planar type, etc..

Maximum size of boring spindle diameter in mm.

Maximum spindle travel in horizontal and vertical directi9on in mm.

Maximum travel of table in longitudinal and crosswise direction in mm.

Why is a jig boring machine called so?

A jig machine is a precision boring machinme used for boring accurate holes at proper centre to centre distance. It is specially designed machine tool for precision location and production of holes needed in jigs, fixtures, dies.

Specify the importance of jig boring machine.

A jig machine is a precision boring machinme used for boring accurate holes at proper centre to centre distance.

It is specially designed machine tool for precision location and production of holes needed in jigs, fixtures, dies.

The maching accuuracy of holes produced by machine tool lies within a range of 0.0025mm.

Built in precision measuring devicesfor axis movement is another speciality of this machine.

Classify sawing machine.

Reciprocating saw

Horizontal sawing machine

Vertical sawing machine

Circular saw

Cold saw

Friction saw

Abrasive disk

Band saw

contour hand saw

Friction bladeWhat is broaching?

Broaching is a process of machining a surface with a special multi point cutting tool called broach which has successively higher cutting edges in fixed path.

What are advantages of broaching?

Roughing, semi finishing and finishingcuts are completed in one pass of the broach.

It can be used for either external or internall surface finish.

What is a main difference between pull up and pull down type vertical broaching machine?

This broach is used in pushtype broaching machine in which the broach is pushed through workduring broaching.

This broach is pullled through work during broaching.What are the various types of broaching tools?

According to method of operation,

Push broach

Pull broach

According to kind of operation

Internal broach

External broach

What are the different operations that can be performed in a broaching machine

Broaching splines

BROAching a keyways

Why is sawing a commonly used process?Easy handling of machines

Fast operation and cost of machinery is less