Design for X (DFX)

Design for X (DFX)- DFX techniques are part of detail design and are ideal approaches to improve life-cycle cost, quality, increased design flexibility, and increased efficiency and productivity using the concurrent design concepts. Benefits are usually pinned as competitiveness measures, improved decision-making, and enhanced operational efficiency. The letter “X” in DFX refers to performance measure or the ability.

DFX provides systematic approaches for analyzing design from a spectrum of perspectives. It strengthens teamwork within the concurrent DFSS environment. DFX focuses on vital business elements of concurrent engineering, maximizing the use of the limited resources available to the DFSS team. The X is used as a variable term that can be substituted with, for example, Assembly, Cost, Environment, Fabrication, Manufacture, Obsolescence, Procurement, Reliability, Serviceability, or Test.

• Design for Manufacture and Assembly – Designs that are constructed to be easy to manufacture during the conceptual stage of a product development are much more likely to avoid redesign later when the system is being certified for production readiness. The best way to ensure a concept can be manufactured is to have active involvement from the production and supply chain organizations during concept generation and selection. These are systematic approaches that the DFSS team can use to carefully analyze each design parameter that can be defined as part or subassembly for manual or automated manufacture and assembly to gradually reduce waste.
• Design for life-cycle cost – Life-cycle cost is the real cost of the design. It includes not only the original cost of manufacture but also the associated costs of defects, litigations, buybacks, distributions support, warranty and the implementation cost of all employed DFX methods. Probability distributions are given to represent inherent cost uncertainty. Monte Carlo simulation and other discrete-event simulation techniques are then used to model uncertainty and to estimate the effect of uncertainty on cost.
• Design for serviceability – It is the ability to diagnose, remove, replace, replenish, or repair any component or subassembly to original specifications with relative ease. Poor serviceability produces warranty costs, customer dissatisfaction, and lost sales and market share due to loss loyalty. The DFSS team may check their VOC (voice-of-the-customer) studies such as QFD for any voiced serviceability attributes. Ease of serviceability is a performance quality in the Kano DFSS strives to have serviceability personnel involved in the early stages, as they are considered a customer segment.
• Design for Reliability – Reliability is the probability that a physical entity delivers its functional requirements (FRs) for an intended period under defined operating conditions. The time can be measured in several ways. For example, time in service and mileage are both acceptable for automobiles, while the number of open-close cycles in switches is suitable for circuit breakers. The DFSS team should use DFR while limiting the life-cycle cost of the design. The assessment of reliability usually involves testing and analysis of stress strength and environmental factors and should always include improper usage by the end user. A reliable design should anticipate all that can go wrong. Various hazard analysis approaches are used like fault-tree analysis.
• Design for Maintainability – The objective of Design for Maintainability is to assure that the design will perform satisfactorily throughout its intended life with a minimum expenditure of budget and effort. Design for maintainability (DFM), Design for Serviceability (DFS), and Design for Reliability (DFR) are related because minimizing maintenance and facilitating service can be achieved by improving reliability. An effective DFM minimizes the downtime for maintenance, user and technician maintenance time, personnel injury resulting from maintenance tasks, cost resulting from maintainability features and logistics requirements for replacement parts, backup units, and personnel. Maintenance actions can be preventive, corrective, or recycle and overhaul. Design for Maintainability encompasses access and control, displays, fasteners, handles, labels, positioning and mounting, and testing.

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