Ultrasonic machining (USM): identify the incorrect statement Evaluate the properties of USM for hard/brittle materials (e.g., glass, ceramics). Choose the statement that is <em>wrong</em> for ultrasonic machining.

Given / Concept
USM uses high-frequency vibrations with an abrasive slurry to micro-chisel brittle materials. It is non-thermal and well-suited to glass, carbides, and ceramics.

Why option (c) is wrong
USM has low MRR compared to conventional cutting or grinding; it does not remove large amounts of material rapidly.

Validation of other options
(a) True — ideal for brittle, hard materials.(b) True — MRR is slow.(d) True — produces fine features and good finishes without heat-affected zones.

Final Answer
It removes large amount of material quickly.