73 practice sets · Page 1 of 4
What are the disadvantages of PBM?
Toxic fumes produced
All of the mentioned
Large power supplies
Heat produced
Correct Answer: B — All of the mentioned
Explanation:
Large power for more thick materials, production of heat and toxic fumes are some of the main disadvantages of PBM.
How much amount of energy is required for machining using PBM?
Very high
Moderate
Low
High
Correct Answer: C — Low
Explanation:
The cost for operating the jobs in Plasma beam machining is less and also less energy is required for operating the machine in PBM.
Which of the following chemicals are used in PBM?
None of the mentioned
Dissolvable solvent chemicals
Harmful chlorinated fluorocarbons
Acid cleaning chemicals
Correct Answer: A — None of the mentioned
Explanation:
Plasma beam machining uses no harmful chlorinated fluorocarbons, acid cleaning chemicals or any dissolvable solvents.
Which of the following are the advantages of PBM?
Less harmful
No chemical analysis
All of the mentioned
Operates cleanly
Correct Answer: C — All of the mentioned
Explanation:
Main advantages of Plasma bema machining are no complicated chemical analysis, less harmful and no harmful exposure and it operates cleanly.
What is the maximum thickness of the walls of tube machined using plasma arc?
30 mm
10 mm
70 mm
50 mm
Correct Answer: D — 50 mm
Explanation:
The maximum thickness of the wall tubes that can be produced using PBM is about 50 mm.
What are the values of tolerances obtained by using PBM?
± 3.6 mm
± 0.6 mm
± 1.6 mm
± 2.6 mm
Correct Answer: C — ± 1.6 mm
Explanation:
The values of the tolerances obtained by using Plasma beam machining will be about ± 1.6 mm.
How much thickness of cracks may arise beyond HAZ due to rapid cooling?
1.6 mm
4.6 mm
3.6 mm
2.6 mm
Correct Answer: A — 1.6 mm
Explanation:
The cracks due to rapid cooling in PBM may extend beyond HAZ to a thickness of 1.6 mm.
What is the thickness of the HAZ in PBM?
1.3 to 2.56 mm
0.25 to 1.12 mm
2.73 to 5.26 mm
0.001 to 0.23 mm
Correct Answer: B — 0.25 to 1.12 mm
Explanation:
The thickness of the HAZ obtained in PBM range from 0.25 to 1.12 mm.
The cut edge of the material tends to be __________ than the base metal in PBM.
Smoother
Harder
None of the mentioned
Same as
Correct Answer: B — Harder
Explanation:
The cut edge of material in PBM tends to be harder than the base metal.
How much distortion is produced while machining using PBM?
10%
20%
30%
No distortion is produced
Correct Answer: D — No distortion is produced
Explanation:
Heat does not penetrate more than few microns from the edges of the cuts produced by machining using PBM that produce no distortion.
What is the machining speed required for machining of 12mm thick plate withkW energy?
1500 mm/min
1000 mm/min
2500 mm/min
2000 mm/min
Correct Answer: C — 2500 mm/min
Explanation:
Machining speed required for cutting 12-mm thick plate with 220 kW power is about 2500 mm/min.
What happens to the machining speed if the thickness of material is increased in PBM?
Remains same
Decreases
Enhanced
Increases
Correct Answer: B — Decreases
Explanation:
Machining speed in Plasma beam machining reduces with an increase in the thickness of the work piece material.
A low power factors indicates __________ energy required and __________ removal rates.
Low, high
Low, low
High, high
High, low
Correct Answer: A — Low, high
Explanation:
A low power factor in Plasma beam machining indicates low energy required and high material removal rates.
Material removal rates depend on which of the following factors?
Shielding gases
Work piece material
Type of cutting
All of the mentioned
Correct Answer: D — All of the mentioned
Explanation:
Material removal rates in PBM depend on work piece material, type of cutting and the shielding gas.
Action of abrasive grains depend on which of the following factors?
All of the mentioned
Hydrodynamic effects
Transport of electrolyte
Electric filed
Correct Answer: A — All of the mentioned
Explanation:
Action pf abrasive grains in the gap depends on the electric field, transport of electrolyte and the hydrodynamic effects.
ECG is a hybrid machining process of which material removal mechanisms below?
Mechanical abrasion
None of the mentioned
Electro chemical dissolution
Mechanical abrasion & Electro chemical dissolution
Correct Answer: D — Mechanical abrasion & Electro chemical dissolution
Explanation:
ECG is a hybrid machining process which uses MA and ECD for material removal.
What are the volumetric removal rates that are obtained in ECG process?
3200 mm³/min
800 mm³/min
400 mm³/min
1600 mm³/min
Correct Answer: D — 1600 mm³/min
Explanation:
The volumetric removal rates that are obtained in Electro chemical grinding process will be around 1600 mm3/min.
How much amount of burr is produce in Electro chemical grinding process?
High amount
Moderate amount
No burrs are produced
Less amount
Correct Answer: C — No burrs are produced
Explanation:
The Electro chemical grinding process is a burr free process which produce parts that are unstressed.
Removal rates of ECG process are how may time to that of the conventional machining processes?
4 times
2 times
5 times
3 times
Correct Answer: A — 4 times
Explanation:
The MRR of ECG process are nearly 4 times that of the conventional machining processes.
Mechanical abrasion counts to how much amount of the material removal in ECG?
10 to 15%
1 to 5%
5 to 10%
15 to 20%
Correct Answer: C — 5 to 10%
Explanation:
Material removal through abrasion counts to 5 to 10% of the total material removed.
