Establishing assembly-oriented modular product architectures through Design for Assembly enhanced Modular Function Deployment

TL;DR

This paper addresses the lack of systematic assembly consideration in early modular product design by extending Modular Function Deployment (MFD) with Design for Assembly (DFA) principles. It introduces assembly-oriented heuristics, a module-driver taxonomy, a coded interface taxonomy, and quantitative metrics (MSASM and TAC) that integrate DFA into early conceptual and architecture decisions without disrupting MFD workflows. Through a handheld leaf blower case study, the approach demonstrates tangible gains: reduced assembly complexity, streamlined interfaces, and enhanced automation potential, evidenced by an increase in MSASM scores from $5.2$ to $7.3$ and a TAC reduction from $26.25$ to $7.25$. The method offers a practical, scalable framework for production-informed modular design, enabling faster ramp-up to volume production and improved lifecycle adaptability, while highlighting areas for industrial validation and tool integration. $MSASM$ and $TAC$ examples illustrate how assembly considerations can be quantified and traded off alongside functional and market criteria to achieve robust, automation-ready architectures.

Abstract

Modular product design has become a strategic enabler for companies seeking to balance product variety, operational efficiency, and market responsiveness, making the alignment between modular architecture and manufacturing considerations increasingly critical. Modular Function Deployment (MFD) is a widely adopted method for defining modular product architectures, yet it lacks systematic support for assembly considerations during early concept and system-level development. This limitation increases the risk of delayed production ramp-up and lifecycle inefficiencies. This paper proposes a set of enhancements to MFD that integrate Design for Assembly (DFA) logic into architectural synthesis. The extended method introduces structured heuristics, assembly-oriented module drivers, a coded interface taxonomy, and quantitative metrics for assessing assembly feasibility and automation readiness. These additions preserve compatibility with standard MFD workflows while enriching decision-making with traceable, production-informed reasoning. An illustrative case study involving a handheld leaf blower demonstrates the method's usability and effectiveness. The redesigned architecture shows reduced assembly effort, simplified interfaces, and increased automation potential. By supporting early-stage evaluation of architectural alternatives through an assembly lens, the method enables faster transition to efficient volume production and provides a foundation for continuous improvement throughout the product lifecycle.

Figures (7)

• Figure 1: Original MFD method (adapted from lange_modular_2014). It links customer requirements to TS through a structured flow of matrices. Evaluation relies on functional and market-related criteria.
• Figure 2: Development of the DFA-enhanced MFD method under DRM. It was developed through systematic review (SLR), industrial insight (DS-I), method proposition (PS-I), and iterative refinement. Arrows indicate feedback loops between stages. Future steps target industrial implementation.
• Figure 3: Expanded MFD method with DFA enhancements. Additions include: (1) assembly internal criteria for technical solution evaluation; (2) assembly-oriented module drivers for module formation; (3) a coded interface taxonomy; (4) the ADCD tool for directional interface planning; and (5) the MSASM for quantitative evaluation of architecture-level assemblability. Fully integrated into the MFD workflow, these additions support proactive assembly-oriented decision-making. The concept evaluation stage also remains open for extensions addressing disassembly or other life-cycle criteria (X).
• Figure 4: Cheat sheet for interpreting the interface code string (e.g., M1-P3-H1-A2-T1-I0-D0). Each component encodes an assembly-relevant attribute: interface type, priority, handling, alignment, tooling, fit, and fixing. The structure enables systematic comparison and complexity scoring.
• Figure 5: Comparison of legacy and expanded modularisation workflows. Bottom-up teardown-based modularisation (left) and assembly-oriented top-down architecture development (right). The proposed method incorporates the added tools.