production some key poins

8/10/2019 Production some key poins

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A single point thread cutting tool should ideally have zero rake angle

The work or surface speed for cylindrical grinding varies from 20 to 30 m/min

Twist drills are made of stainless steel or high speed steel . It is an end cutting tool

The rake angle reuired to machine !rass !y high speed steel tool is 0"

The average cutting speed for turning !rass with a high speed steel tool is #0 to $0 m/min

The method of grinding used to produce a straight or tapered surface on a workpiece% is external cylindrical

grinding

Gear lapping is an operation after heat treatment

A drill considered as a cutting tool having zero rake% is known as a straight fluted drill

Thelead screw of a lathe has single start threads.

Aleft hand tool on a lathe cuts most efficiently when it travels from left to right end of the lathe !ed

tool materials in increasing order of their a!ility to retain their hot hardness is cermet% car!ide% ceramic%

!orazon

In the relation &T'n ( )% the value of n for car!ide tools is 0.20 to 0.2*

The machining of titanium is difficult due to ow tool+chip contact area

If the heli, angle of the drill is madeless than 30"% then the torue reuired to drive the drill at a given feed will

!e more.

The velocity of tool relative to the workpiece is known as cutting velocity

Gear hobbing is a machining process in which gear teeth are progressively generated !y a series of cuts with a

helical cutting tool. All motions in ho!!ing are rotary% and the ho! and gear !lank rotate continuously as in two

gears meshing until all teeth are cut.

Cemented carbides are composed of a metal matri, composite where car!ide particles act as the aggregate

and a metallic !inder serves as the matri,. The process of com!ining the car!ide particles with the !inder is

referred to as sintering or -ot Isostatic ressing -I. 1uring this process the !inder eventually will !e entering

the liuid stage and car!ide grains much higher melting point remain in the solid stage. As a result of this

process the !inder is em!edding/cementing the car!ide grains and there!y creates the metal matri, composite

with its distinct material properties. The naturally ductile metal !inder serves to offset the characteristic !rittle

!ehavior of the car!ide ceramic% thus raising its toughness and dura!ility. uch parameters of car!ide can !e

changed significantly within the car!ide manufacturers sphere of influence% primarily determined !y grain size%

cobaltcontent% dotation e.g. alloy car!ides and car!on content.

Trepanningis an operation of producing a hole !y removing metal along the circumference of a hollow cutting


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tool

The a!rasive recommended for grinding materials of high tensile strength is aluminium o,ide

In centreless grinding% the surface speed of regulating wheel is 4* to #0 m/min

Thread grinding reuires work speed from 4 to 3 m/min

Glazingin grinding wheels can !e decreased !y using a softer wheel or !y decreasing the wheel speed

Down milling is also called clim! milling

The depth of cut in drilling is one+half the drill diameter.

In centreless grinders% the ma,imum angular ad5ustment of the regulating wheel is 40"

The snag grinding is done to remove considera!le amount of metal without regard to accuracy of the finished

surface

The trade name of a non+ferrous cast alloy composed of co!alt% chromium and tungsten is called stellite

-igh speed steel cutting tools operate at cutting speeds 2 to 3 times higher than car!on steel tools.

In lapping operaion% the amount of metal removed is 0.00* to 0.04 mm

The cutting speed for drilling copper with high speed steel drills varies from 46 to 30 m/min7

-igh speed steel tools retain their hardness upto a temperature of $00")

)eramic tools are fi,ed to tool !ody !y !razing

The main purpose of a boringoperation% as compared to drilling% is to enlarge the e,isting hole

Carbide tipped tools usually have negative rake angle

The saw milling is an operation of producing narrow slots or grooves on a workpiece

The type of reamer used for reaming soft aluminium or copper% is left hand spiral fluted reamer

8ow heli, angle drills are preferred for drilling holes in plastics

Inplunge grinding the work rotates in a fi,ed position as the wheel feeds to produce cylinders eual to or

shorter than the width of wheel face

In drilling operation% the metal is removed !y shearing and e,trusion

In the relation &Tn ( )% the value of n for ceramic tools is 0.90 to 0.**

The actual speed in centreless grinders is given !y where d ( 1ia. of regulating wheel% n ( :evolutions per

minute% and ; ( Angle of inclination of wheel


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Gang drilling machine to perform the operations like drilling% reaming% counter+!oring etc. on a work piece.

The lathe centres are provided with standard taper known as morse taper

In a plain milling cutter% the chip space !etween the !ack of one tooth and the face of the ne,t tooth is called

gash

In machining%boring is the process of enlarging a hole that has already !een drilled or cast% !y means of a

single+point cutting tool or of a !oring head containing several such tools% for e,ample as in !oring a gun

!arrel or an engine cylinder. =oring is used to achieve greater accuracy of the diameter of a hole% and can !e

used to cut a tapered hole. =oring can !e viewed as the internal+diameter counterpart to turning% which cuts

e,ternal diameters.

vertical boring mills workpiece rotates around a vertical a,is while !oring !ar/head moves linearly> essentially

a vertical lathe and horizontal boring mills workpiece sits on a ta!le while the !oring !ar rotates around a

horizontal a,is> essentially a specialized horizontal milling machine

The cutting fluid mostly used for machining alloy steels is sulphurised mineral oil

The operation of smoothing and suaring the surface around a hole is known as spot facing

:elief angles on high speed steel tools usually vary from 20" to 30"

A drill mainly used in drilling !rass% copper or softer materials% is straight fluted drill

?or machining a mild steel workpiece !y a high speed steel tool% the average cutting speed is 30 m/min

A tool used to withdraw a drill from the sleeve is called drift

The lip angle is the angle !etween the tool face and the ground end surface of flank

mall nose radius results in e,cessive stress concentration and greater heat generation

wheel clogging can lead to an overloading of the grinding wheel% high grinding wheel wear and to thermal

damage of the workpiece

oft materials can not !e economically ground due to freuent wheel clogging

The grinding wheel speed surface speed in m/min usually varies from 4*00 to 2000

In a milling operation% two side milling cutters are mounted with a desired distance !etween them so that !oth

sides of a workpiece can !e milled simultaneously. This set up is called straddle milling.

)rack in grinding wheel is developed due to high speed of wheel

The average cutting speed for turning mild steel with a high speed steel tool is 2* to 34 m/min

The relief or clearance at the cutting edge of a flat drill varies from 3" to 6"

In centreless grinders% the regulating wheel is inclined at 0" to 6"


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Spot facingis an operation of smoothing and suaring the surface around a hole

The operation of making a cone+shaped enlargement of the end of a hole is known as counter-sining

Internal or e,ternal threads of different pitches can !e produced !y planetary milling machine

)eramic cutting tools are made !y cold pressing of aluminium o,ide powder% availa!le in the form of tips %

!rittle and have low !ending strength

Tapping+Internal threads in the holes of workpieces are produced !y taps. After tapping% the tool is

mechanically collapsed and removed without having to rotate it. izes up to 9 in.

Core Drilling + 1rill a larger hole on a smaller hole.

Step drilling + 1ou!le sized drill

Counterboring + stepper hole. @seful to seat !olt heads in the holes.

Countersining+-ole is cone shaped for flat head screws.

!eaming+ nlarge the hole% provide !etter tolerance/finish.

Center Drilling + To !egin the center for a hole.

Gun Drilling+ deep holes with aspect ratios B 300

production some key poins

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