Advanced Machining : Practice Questions and Answers

Large power for more thick materials, production of heat and toxic fumes are some of the main disadvantages of PBM.

The cost for operating the jobs in Plasma beam machining is less and also less energy is required for operating the machine in PBM.

Plasma beam machining uses no harmful chlorinated fluorocarbons, acid cleaning chemicals or any dissolvable solvents.

Main advantages of Plasma bema machining are no complicated chemical analysis, less harmful and no harmful exposure and it operates cleanly.

The maximum thickness of the wall tubes that can be produced using PBM is about 50 mm.

The values of the tolerances obtained by using Plasma beam machining will be about ± 1.6 mm.

The cracks due to rapid cooling in PBM may extend beyond HAZ to a thickness of 1.6 mm.

The thickness of the HAZ obtained in PBM range from 0.25 to 1.12 mm.

The cut edge of material in PBM tends to be harder than the base metal.

Heat does not penetrate more than few microns from the edges of the cuts produced by machining using PBM that produce no distortion.

Machining speed required for cutting 12-mm thick plate with 220 kW power is about 2500 mm/min.

Machining speed in Plasma beam machining reduces with an increase in the thickness of the work piece material.

A low power factor in Plasma beam machining indicates low energy required and high material removal rates.

Material removal rates in PBM depend on work piece material, type of cutting and the shielding gas.

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 which uses MA and ECD for material removal.

The volumetric removal rates that are obtained in Electro chemical grinding process will be around 1600 mm3/min.

The Electro chemical grinding process is a burr free process which produce parts that are unstressed.

The MRR of ECG process are nearly 4 times that of the conventional machining processes.

Material removal through abrasion counts to 5 to 10% of the total material removed.