Identifying Failure Modes and Effects Through Design for Assembly Analysis

Abstract

Design for Assembly (DFA) time estimation method developed by G. Boothroyd and P. Dewhurst allows for estimating the assembly time of artifacts based on analysis of component features using handling and insertion tables by an assembler, who is assumed to assemble the artifact one-part-at-a-time. Using the tables, each component is assigned an assembly time which is based on the time required for the assembler to manipulate (handling time) and the time required for it to interface with the rest of the components (insertion time). Using this assembly time and the ideal assembly time (i.e. the absolute time it takes to assemble the artifact, assuming each component takes the ideal time of three seconds to handle and insert), this method allows to calculate the efficiency of a design’s assembly process. Another tool occasionally used in Design for Manufacturing (DFM) is Failure Modes and Effects Analysis (FMEA). FMEA is used to evaluate and document failure modes and their impact on system performance. Each failure mode is ranked based on its severity, occurrence, and detectability scores, and corrective actions that can be taken to control risk items. FMEA scores of components can address the manufacturing operations and how much effort should be put into each specific component. In this paper, the authors attempt to answer the following two research questions (RQs) to determine the relationships between FMEA scores and the DFA assembly time to investigate if part failure’s severity, occurrence, and detectability can be estimated if handling time and insertion time are known. RQ (1): Can DFA metrics (handling time and insertion time) be utilized to estimate Failure Mode and Effects scores (severity, occurrence, and detectability)? RQ (2): How does each response metric relate to predictor metrics (positive, negative, or no relationship)? This is accomplished by performing Boothroyd and Dewhurst’s DFA time estimation and FMEA on select set of simple products. Since DFA metrics are based on combination of designer’s subjectivity and part’s geometric specifications and FMEA scores are based only on designer’s subjectivity, this paper attempts to estimate part failure severity, occurrence, and detectability less subjectively by using the handling time and insertion time. This will also allow for earlier and faster acquisition of potential part failure information for use in design and manufacturing processes.

Design for manufacturing and assembly methods in the product development process of mechanical products: a systematic literature review

“…Other works published in conference proceedings are trying to extend DFMA principles in several ways. For example, Esterman and Kamath [27] attempted to apply DFMA to the improvement of assembly lines, Wood et al [28] and Nyemba et al [29] provided new design rules to cope with constraint production of the developing countries, and finally Favi et al [2], Hein et al [30], and Gupta and Kumar [31] included new principles and criteria for multi-objective analysis (i.e., cost, sustainability).…”

Product low‐carbon design, manufacturing, logistics, and recycling: An overview

“…Other works presented in the conference proceedings attempt to extend the DFMA principles in several ways (i.e., cost, sustainability, etc. ), for example, Wood et al (2014) and Wood et al (2014) provide new design rules to deal with constrained production in developing countries, and Hein et al (2018) and Gupta and Kumar (2019) incorporate new principles and criteria for multi-objective analysis. They found that one of the main difficulties was converting design specifications into valuable information for managing the selection and other essential stages of product development.…”