Design for Assembly (DFA): Is it true that DFA is not important because assembly operations contribute little to total product cost?

Introduction / Context:
Design for Assembly (DFA) focuses on reducing part count, simplifying joins, improving orientation, and enabling mistake-proofing (poka-yoke). Assembly can represent a significant share of product cost and strongly affects quality, throughput, and time-to-market. The statement that DFA is unimportant because assembly contributes little to cost is misleading and generally false.

Given Data / Assumptions:

• Typical products require multiple parts and joining operations.
• Labor, fixtures, rework, and yield losses add to assembly cost.
• Early design choices lock the majority of lifecycle cost.

Concept / Approach:
DFA aims to minimize handling/orientation time, reduce fasteners, combine functions, and standardize features. These choices cut direct labor, shorten cycle times, improve first-pass yield, and reduce training/fixture complexity—benefits that persist whether assembly is manual or automated.

Step-by-Step Solution:

Verification / Alternative check:
Compare two designs: one DFA-optimized and one baseline. Measure takt time, station count, and defect rate. DFA usually lowers total cost of ownership and speeds ramp-up, even when raw material dominates BOM cost.

Why Other Options Are Wrong:
“Correct” contradicts widespread evidence. Limiting statements like “True only for automated lines,” “snap-fit only,” or “depends solely on material prices” ignore labor, quality, WIP, and capital utilization.

Common Pitfalls:
Late DFA after tooling freeze; optimizing parts in isolation; ignoring ergonomics and serviceability; underestimating changeover and learning-curve impacts.

Final Answer:
Incorrect