Recent Twomarks Document (4)

7/26/2019 Recent Twomarks Document (4)

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Manufacturing Technology (ME-6352)-Two marks

1. What is the difference between progressive solidification and directional solidification?

Progressive solidification involves the transformation metal in to the solid

state.Directional solidification is used to describe the aspect of freezing process and which it iscontrolled from the zone of freezind area to the riser to prevent shrinkage voids during freezing.

2. What are the common allowances provided in the pattern ? why?

i !hrinkage allowance

ii "achining allowance

iii #aper allowance

$iv !hake and distortion allowance

%. What are the limitations of resistance welding process?

1. &mount of current passing through the work piece

2. #he pressure that electrodes that transfers to the work piece.

%. #ime during which the current flows

'. &rea of electrode tip in contact with the workpiece.

'. (ive the causes and remedies for undercut and hot cracking?

&d)acent to the weld* the formation of groove is called undercut. Due to non uniform

feed of welding rod* improper position of the electrode or e+cessive heating.

,ot cracking due to lot of stresses set up by non uniform heating and cooling* e+cess

sulphur or phosphorous in the weld metal.

-. What are the differences between shaper and planer?

!haper is a reciprocating type of machine tool intended primarily produce flat surfaces

may be horizontal*vertical*or inclined.

Planer is a machine tool primarily intended for machining large flat surfaces *these

surfaces may be horizontal* vertical or inclined. Planer is capable of machining heavy work

pieces which cannot be accommodated in shaper table.

. (ive the difference between counter boring and counter sinking?



/ounter boring0 t is the operation of enlarging a entry of the drilled hole by using

counter boring tool to accommodate the bolt head etc.

/ounter sinking0 t is the operation to bevel the top of a drilled hole for making a conical

seat.counter sink tool is used for this operation.

. What is thermoforming and write its applications?

t is a series of processes for forming thermo plastic sheet or film over a mould with the

application of heat and pressure.which is used for making flat wares *gears

*buttons*buckles*knobs*handles*electrical and electronics components and washing machine

housings and agitators.

3. What are reinforced plastics?

#hese plastics are laminated with the fibres* asbestos* boron* cotton and nylon fibres.the

reinforced plastics are used for storage bins* machinery housings* aircraft panels.

4. What is spring back? ,ow it overcome in sheet metal work?

!pring back is beyond as the movement of the metal to resume its original position

causing a

Decrease in bend angle after the applied force is withdrawn.

15. What are the various forging defects?

/old laps Die shift /racks 6lakes De carbonization

11. 7ist out the basic ingredients of molding sand and their purpose?

#he principal ingredients of moulding sands are asilica sands and grains bclay

cmoisture dmiscellaneous materials. !ilica is the granular 8uartz *itself a sand impart

refractoriness*chemical resistivity and permeability to the sand. /lay imparts the bonding

strength to the molding sand *so that the mould does not lose its shape after ramming.

12. Define the term green strength and e+plain its importance in the conte+t of molding?

#his property of sand in its green or moist state is known as green strength. & mould

having ade8uate green strength will retain its shape and will not distort or collapse even after the

pattern is removed from the molding bo+.

1%. 9+plain the term weld ability and give two e+amples of metal and alloys?



Weld ability is defined as the capacity of the material to be welded under fabrication

conditions imposed in a specific and suitably designed structure to perform satisfactorily in the

intended service. "ild steel* cast iron* stainless steel* aluminum alloys* magnesium alloys.

1'. (ive the advantages of resistance welding?

1. :ery little skill

2. ,igh production rate

%. ,eating is confined to small area

'. ;o flu+ and no filler rod re8uired.

-. !emi automatic e8uipments are available

. !imilar and dissimilar metals can be welded.

1-. What are the factors affecting mach inability?

1. "etal of casting

2. "achining method used

%. /asting method used

'. !hape and size of casting

-. &mount of finish re8uired on the machined portion.

1. Write the functions of dielectric fluid in 9D" process?

1. #o keep away the chips from the welding area

2. #o accelerate the 9D" machining process

%. #o act as a cooling medium.

1. !tate three types of compression molding and their utilities?

/ompression molding is used for making flat wares* gears* buttons* buckles* knobs*

handles* electrical and electronics components and washing machine housings and agitators.



13. What are the different types of castings?

/onventional method0 (reen sand mould casting* dry sand mould casting

<nconventional methods0

14. What are the casting defects?

$i Dirt

$ii Porosity

$iii =low

$iv Dross

$v !cab

$vi (as hole

$vii !car

$viii nclusion

$i+ =lister

$+ Pinholes

25. !tate the working principle of o+yacetylene welding process?

When acetylene in correct proportion* is mi+ed with o+ygen in welding torch and ignited then

the flame resulting at the tip of the torch is sufficiently hot to melt and )oin the parent metals.

21. 7ist out the limitations of electron beam welding?

$i nitial cost of e8uipment is high and portable e8uipment is rare

$iiWork is to be manipulated through vacuum seals.

$iii#ime and e8uipment is re8uired to create vacuum very time a new )ob

is to be welded.

$iv Precaution are needed to prevent damage from >rays

22. (ive the applications of 9D"?

1. "icro machining* 2.micro drilling %. "achining in)ector nozzle for diesel engines.



2%. !tate the working principle of blow molding?

n blow molding* the plastic is fed in a granular form in to the heated section*n this heated

section the granular form melted in to the li8uid and fed in to themould. #he air is forced in to

the mould which forces the plastic in to sides *give the shape of mould.#he mould is cooled and

removed.

2'. !tate the difference between e+trusion and wire drawing?

#he e+trusion process consists of compressing a metal inside a chamber to force it out through a

small opening which is called die.

2-. What are the advantages of special casting process over sand casting processes?

$i (reater dimensional accuracy

$ii ,igher metallurgical 8uality

$iii 7ower production cost

$iv ,igh production rate

2. What are the three types of centrifugal casting?

$i #rue centrifugal casting

$ii !emi centrifugal casting

$iii /entrifuge casting

2. What are the methods involved in brazing?

$i #orch brazing

$ii 6urnace brazing

$iii nduction brazing

$iv @esistance brazing

$v Dip brazing

$vi nfrared brazing

23. What are the advantages of compression moulding?

A 7ittle waste $no gates* sprues* or runners in many molds

A 7ower tooling cost than in)ection molding

A (ood surface finish



A 7ess damage to fibers

A Process may be automated or handoperated

A "aterial flow is short* less chance of disturbing inserts* causing product stress* andBor eroding

molds.

24. What are the disadvantages of compression moulding?

A ,igh initial capital investment

A 7abor intensive

A !econdary operations maybe re8uired

A 7ong molding cycles may be needed.

%5. Define cold moulding.

/harge is pressed into shape while cold then cured in an oven. 9conomical but usually poor

surface finish.

%1. Define e+trusion process.

9+trusion is the process of s8ueezing metal in a closed cavity through a tool* known as a die

using either a mechanical or hydraulic press.

%2. What are the advantages of stretched forming operations?

1. =lanks can be stretched in a single operation

2. ;o need of any heattreatments before and after the stretching process.

%. !pring back is reduced or eliminated when compared to other forming methods

'. Direct bending is not introduced

%%. 7ist out the applications of stretch forming operations.

1. Production of aircraft wing and fuselage parts.2. Production of contoured panels for truck

trailer and bus bodies in automobile industry

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Recent Twomarks Document (4)