In production engineering, what is the principal purpose of using jigs and fixtures during machining and assembly operations?

Introduction / Context:
Jigs and fixtures are essential workholding and guidance devices in manufacturing. They position, clamp, and locate parts while guiding tools (jigs) or simply holding the work (fixtures) to reduce variability and increase throughput. The question probes their broad benefits on quality and cost.

Given Data / Assumptions:

• Repetitive or batch production environment.
• Standardized components with specified tolerances.
• Skilled or semi-skilled operators using dedicated setups.

Concept / Approach:
By ensuring consistent location and orientation, jigs and fixtures reduce setup errors and improve repeatability. This raises accuracy, enables interchangeability (parts fit without selective assembly), and reduces inspection time and rework, lowering quality control expenditure overall.

Step-by-Step Solution:

Verification / Alternative check:
Compare process capability indices (Cp/Cpk) with and without dedicated fixtures; capability improves, supporting reduced QC costs and higher first-pass yield.

Why Other Options Are Wrong:

• Each single benefit is valid, but the full purpose is comprehensive, so “all of these” is best.
• “None of these” contradicts established manufacturing practice.

Common Pitfalls:
Assuming jigs/fixtures only improve speed; in reality, accuracy and consistency gains are primary and directly influence cost and quality.

Final Answer:
all of these