Manufacturing process: For which applications is broaching typically used in practice?

Introduction / Context:
Broaching is a high-productivity machining process where a multi-tooth tool (the broach) is pushed or pulled past the work to remove metal in a single pass. It is widely used for internal profiles such as keyways and splines, as well as for external flats and contours. This question checks your understanding of the scope of parts and surfaces that can be produced by broaching.

Given Data / Assumptions:

• The broach has progressively taller teeth that perform roughing to finishing in one stroke.
• Fixtures and guides are available to control alignment for internal or external features.
• Production context favors repeatability and speed over flexible toolpaths.

Concept / Approach:
Because the broach's tooth geometry is pre-formed, any shape that can be guided through the work envelope within force limits can be reproduced—internal (holes, splines, polygons), external (flats, slots, contours), and specialized (rifling, turbine root forms). Broaching excels when the same geometry is repeated in medium to high volumes.

Step-by-Step Solution:

Verification / Alternative check:
Industry case studies and tooling catalogs show dedicated internal broaches (push/pull) and surface broaches (external) for a wide range of geometries, confirming the comprehensive capability of the process.

Why Other Options Are Wrong:

• External flat and contoured surfaces: true, but not the only use.
• Round or irregular shaped holes: true, but not the only use.
• Internal and external surfaces: true, but still not exhaustive.
• Only keyways inside hubs: overly restrictive; broaching is applicable far beyond keyways.

Common Pitfalls:
Believing broaching is only for internal keyways; ignoring the need for precise fixturing and the high initial cost of custom broaches which is justified by production quantities.

Final Answer:
all of these