Planer kinematics in shaping large work Which description correctly characterizes the fundamental motion in a planer during machining?

Introduction / Context:Planers and shapers are often contrasted by which element reciprocates. Understanding this difference guides fixture design and selection of machine for very large components.

Given Data / Assumptions:

• Traditional double-housing planer or open-side planer.
• Single-point tool mounted on a tool head or rail.
• Large, heavy workpieces requiring long strokes.

Concept / Approach:In a planer, the work table carrying the workpiece reciprocates linearly beneath a stationary cutting tool (except for feeds and small positioning motions). This arrangement allows massive workpieces to be machined with reduced moving tool mass, improving rigidity. By contrast, in a shaper the tool ram reciprocates while the work remains stationary on a small table.

Step-by-Step Solution:

Verification / Alternative check:Machine tool texts: “Planer → work reciprocates; Shaper → tool reciprocates.”

Why Other Options Are Wrong:Stationary work with reciprocating tool describes a shaper, not a planer.Other options add motions (continuous/circular/rotary) not present in planing.

Common Pitfalls:Confusing planer with plano-miller (where rotating cutters mill while the table feeds slowly); planing uses single-point cutting with reciprocation.

Final Answer:

Tool is stationary and work reciprocates under the tool