73 practice sets · Page 2 of 4
The grinding wheel is _________ and the work piece is ________ in ECG process.
Cathode, anode
Cathode, cathode
Anode, anode
Anode, cathode
Correct Answer: A — Cathode, anode
Explanation:
The grinding wheel is cathode and the work piece is anode in the Electro chemical grinding process.
What is the main mechanism of material removal in Electro chemical grinding?
Electron removal from material
Electro chemical dissolution
Melting and vaporization
Mechanical erosion of material
Correct Answer: B — Electro chemical dissolution
Explanation:
Electro chemical grinding process removes the material mainly by electro chemical dissolution.
Current density depends on which of the following factors?
Applied voltage
All of the mentioned
Gap width
Machined material
Correct Answer: B — All of the mentioned
Explanation:
The current density values in Electro chemical grinding depend on machined material, gap width and the applied voltage.
What are the values of current densities used in the ECG process?
240 to 480 A/cm²
120 to 240 A/cm²
60 to 120 A/cm²
1 to 60 A/cm²
Correct Answer: B — 120 to 240 A/cm²
Explanation:
The values of current densities range from 120 to 240 A/cm2.
What is the value of gap voltage maintained in ECG process?
500 to 5000 V
1 to 10 V
4 to 40 V
40 to 400 V
Correct Answer: C — 4 to 40 V
Explanation:
The value of the gap voltage in ECG process is 4 to 40 V.
Which of the following lasers is used for ceramic materials in LBM?
None of the mentioned
Nd-YAG
Pulsed CO2
Pulsed CO2 & Nd-YAG
Correct Answer: D — Pulsed CO2 & Nd-YAG
Explanation:
Both pulsed CO2 and Nd-YAG lasers can be used for ceramic materials in LBM.
Which of the following lasers is used for organics and non-metallic materials in LBM?
Ruby
Nd-YAG
CO2 + gas assisted
Pulsed CO2
Correct Answer: D — Pulsed CO2
Explanation:
Pulsed CO2 laser is used for organics and non-metallic materials in Laser beam machining process.
Which of the following lasers is used for slitting of thin plastic materials in LBM?
Nd-YAG
Ruby
CO2 only
CO2 + gas assisted
Correct Answer: C — CO2 only
Explanation:
CO2 laser is used for slitting of thin plastic materials in Laser beam machining process.
Which of the following lasers is used for slitting of thin metallic materials in LBM?
CO2 only
CO2 + gas assisted
Nd-YAG
Ruby
Correct Answer: C — Nd-YAG
Explanation:
Nd-YAG laser is used for slitting of thin metallic materials in Laser beam machining process.
Which of the following lasers is used for cutting thick materials in LBM?
Nd-YAG
CO2 only
Ruby
CO2 + gas assisted
Correct Answer: D — CO2 + gas assisted
Explanation:
CO2 + gas assisted laser is used for cutting thicker materials in Laser beam machining process.
Which type of laser can be used for direct drilling or percussion?
Nd-YAG laser
None of the mentioned
Ruby & Nd-YAG laser
Ruby laser
Correct Answer: C — Ruby & Nd-YAG laser
Explanation:
Both Ruby and Nd-YAG laser can be used for direct (percussion) drilling purpose.
Which type of holes can be drilled using Nd-YAG laser?
Small & Large holes
Small holes
None of the mentioned
Large holes
Correct Answer: A — Small & Large holes
Explanation:
Nd-YAG laser can be used for drilling small holes as well as large holes by trepanning process.
Which of the following materials can be easily separated by laser scribing?
Ceramic
Glass
All of the mentioned
Silicon
Correct Answer: C — All of the mentioned
Explanation:
Brittle materials such as silicon, glass and ceramics may be effectively shaped or separated by laser scribing.
Material removal rates which are about mg/pulse produces which type of holes?
All of the mentioned
Shallow
Deep
Very deep
Correct Answer: B — Shallow
Explanation:
In LBM, material removal at the rate of milligrams per pulse produces shallow holes in the material.
Lasers of which type are used for modification of electronic components?
All of the mentioned
High power
Small spot size
Short pulse length
Correct Answer: A — All of the mentioned
Explanation:
Lasers of high power density, small spot size and short pulse length are useful devices for modification of electronic components.
The advantages of excimer laser are due to __________ laser wavelength and _________ pulse duration.
Short, short
Long, long
Long, short
Short, long
Correct Answer: A — Short, short
Explanation:
The practical advantages of excimer laser are mainly due to short laser wavelength and pulse duration.
What are the values of thickness used is fine cutting process?
0.01 to 0.05 mm
15 to 50 mm
0.05 to 0.1 mm
0.5 to 15 mm
Correct Answer: D — 0.5 to 15 mm
Explanation:
The thickness of material used in fine cutting process vary from 0.5 to 16 mm.
Work piece tilting depends on which of the following factors?
Beam speed
All of the mentioned
Incident power
Groove direction
Correct Answer: B — All of the mentioned
Explanation:
Work piece tilting depends on the incident power, beam speed, groove direction, and optical absorption coefficient of the material.
How the grooves in grinding wheels are produced using laser?
Evaporation & Damage of composite
Evaporation
Damage of composite
None of the mentioned
Correct Answer: A — Evaporation & Damage of composite
Explanation:
Grooves on the grinding wheels are produced due to evaporation and damage of the composite wheel material.
Which of the following are the other applications of LBM?
Dressing of grinding wheels
All of the mentioned
Micromachining
Scribing
Correct Answer: B — All of the mentioned
Explanation:
Dressing of grinding wheels, scribing, micromachining, controlled fracturing are some of the other applications of Laser beam machining.
