Centerless plunge (infeed) grinding parameters For plunge grinding on a centerless grinder, the process requires very ______ work (regulating wheel) speed to achieve stability and dimensional control.

Introduction / Context:
In centerless grinding, through-feed and infeed (plunge) modes behave differently. Infeed grinding is used for shoulders, grooves, and profiles, where the workpiece does not translate axially past the wheel. The regulating wheel controls rotational speed and support.

Given Data / Assumptions:

• Plunge (infeed) centerless configuration; no axial feed of the work.
• Work is supported by a work-rest blade and rotated by the regulating wheel.

Concept / Approach:
For stability and to prevent chatter, the work rotational speed is intentionally kept relatively low in plunge grinding. The grinding wheel operates at high surface speed, while the regulating wheel sets a slow rotational speed adequate for grinding forces and cooling without inducing lobing or instability.

Step-by-Step Solution:
Identify mode: infeed (no axial through-feed), requiring rotational support only.Set regulating wheel speed low to maintain control and avoid thermal damage.Conclude: plunge grinding uses very low work speed.

Verification / Alternative check:
Machine setup guides list typical regulating wheel surface speeds that are much lower than the grinding wheel for plunge operations, emphasizing slow, steady rotation.

Why Other Options Are Wrong:

• High (A) risks chatter and lobing.
• Moderate/higher than through-feed (C) contradicts usual practice.
• Zero (D) is impossible; rotation is required for roundness.
• Variable sinusoidal (E) is not used; speed should be steady.

Common Pitfalls:
Setting excessive work speed causing chatter; insufficient support angle; incorrect work-rest blade height producing out-of-round parts.

Final Answer:
low