Broaching tool design In a standard push or pull broach used for internal or surface broaching, how does the height of successive teeth vary along the tool length?

Introduction / Context:
Broaching is a high-production machining process that uses a multi-tooth tool to remove metal in a single pass. Understanding tooth geometry—especially how tooth height changes along the broach—is fundamental to why broaching achieves accuracy, surface finish, and short cycle time.

Given Data / Assumptions:

• The tool is a conventional broach (internal or surface type).
• Each tooth removes a small layer of material called rise per tooth.
• The broach carries roughing, semi-finishing, and finishing teeth in one tool.

Concept / Approach:
The tooth height must increase progressively so that each subsequent tooth removes slightly more depth than the previous one until the final geometry is reached. After roughing teeth, semi-finishing teeth reduce scallops, and finishing teeth (often with equal height) refine size and surface finish.

Step-by-Step Solution:

Verification / Alternative check:
Shop practice and tool catalogs specify a defined rise per tooth (for example, 0.02–0.08 mm per tooth depending on material), confirming progressive increase through roughing and semi-finishing sections.

Why Other Options Are Wrong:
Same throughout: would not remove material progressively; only the first tooth would cut.Progressively decreasing: later teeth would not engage; cutting would cease prematurely.None of these / exceptions: while finishing teeth may be equal, the general cutting section increases progressively.

Common Pitfalls:
Confusing the finishing section (equal height) with the entire broach. The question concerns the overall cutting principle, not just the last few teeth.

Final Answer:

In progressively increasing order