In ECM, the material removal is due to
Corrosion
Erosion
Fusion
Ion displacement
Correct Answer :
D. Ion displacement
Related Questions
The maximum possible draft in cold rolling of sheet increases with the
Increase in coefficient of friction
Decrease in coefficient of friction
Decrease in roll radius
Decrease in roll velocity
In drilling aluminium, a drill with
Zero helix angle is used
Low helix angle is used
High helix angle is used
Any helix angle can be used
The saw milling is an operation of
Producing grooves around the periphery of a cylindrical or conical workpiece
Producing narrow slots or grooves on a workpiece
Reproduction of an outline of a template on a workpiece
Machining several surfaces of a workpiece simultaneously
The rake angle required to machine brass by high speed steel tool is
0°
10°
20°
100°
Which of the following operation is first performed?
Spot facing
Boring
Tapping
Drilling
In up-cut milling the work piece is fed
Against the rotating cutter
At angle of 60° to the cutter
In the direction of the cutter
At the right angle to the cutter
The object of caulking in a riveted joint is to make the joint
Free from corrosion
Stronger in tension
Free from stresses
Leak-proof
The hardness of a grinding wheel is specified by
Brinell hardness number
Rockwell hardness number
Vickers pyramid number
Letter of alphabet
Gear lapping is an operation
After heat treatment
Prior to heat treatment
For gear reconditioning
None of these
Crack in grinding wheel is developed due to
High temperature developed at the contact of the wheel face and work
Grinding hard work
Low speed of wheel
High speed of wheel
The material property which depends only on the basic crystal structure is
Fatigue strength
Work hardening
Fracture strength
Elastic constant
In oblique cutting system, the cutting edge of the tool
May clear the width of the workpiece
May or may not clear the width of the workpiece
May not clear the width of the workpiece
Should always clear the width of the workpiece
In a single point turning operation with a cemented carbide and steel combination having a Taylor exponent of 0.25, if the cutting speed is halved, then tool life will become
Half
Two times
Eight times
Sixteen times
Two plates of the same metal having equal thickness are to be butt welded with electric arc. When the plate thickness changes, welding is achieved by
Adjusting the current
Adjusting the duration of current
Changing the electrode size
Changing the electrode coating
In gear hobbing
Only hob rotates
Only gear blank rotates
Both hob and gear blank rotates
Neither hob nor gear blank rotates
Which of the following statement is correct about nose radius?
It improves tool life
It improves the surface finish
Both (A) and (B)
None of these
The obtuse angle, included between the chisel edge and the lip as viewed from the end of a drill, is called
Helix or rake angle
Point angle
Chisel edge angle
Lip clearance angle
A coarse grained grinding wheel is used to grind
Hard and brittle materials
Soft and ductile materials
Hard and ductile materials
Soft and brittle materials
Discontinuous chips are formed during machining of
Brittle metals
Ductile metals
Hard metals
Soft metals
Ceramic tools are fixed to tool body by
Soldering
Brazing
Welding
Clamping
The binding material used in cemented carbide tools is
Tungsten
Chromium
Silicon
Cobalt
If the tearing efficiency of a riveted joint is 50%, then ratio of rivet hole diameter to the pitch of rivets is
0.20
0.30
0.50
0.60
The tool may fail due to
Cracking at the cutting edge due to thermal stresses
Chipping of the cutting edge
Plastic deformation of the cutting edge
All of these
In ultrasonic machining, the metal is removed by
Using abrasive slurry between the tool and work
Direct contact of tool with the work
Maintaining an electrolyte between the work and tool in a very small gap between the two
Erosion caused by rapidly recurring spark discharges between the tool and work
Which of the following operations can be performed with milling cutters?
Cutting key ways on shafts
Cutting external screw threads
Cutting teeth of spur gears
All of these
The trade name of a nonferrous cast alloy composed of cobalt, chromium and tungsten is called
Ceramic
Stellite
Diamond
Cemented carbide
The top and sides of the table of a shaper usually have
L-type slots
T-type slots
I-type slots
Any one of these
The size of a lathe is specified by the
Length between centres
Swing diameter over the bed
Swing diameter over the carriage
All of these
As the cutting speed increases, the tool cutting forces
Remain constant
Increases
Decreases
First increases and then decreases
In machining metals, chips break due to __________ of work material.
Toughness
Ductility
Elasticity
Work hardening