Every product designer is, or should be, familiar with DFX, or Design for X--the practice of incorporating different tangential factors into the design of a product that are intended to better integrate the new product with downstream activity. One of the more familiar DFX practices is design for manufacturing (DFM), where engineers design a product to be easier, safer and less costly to manufacture. The designer may decide on source materials that are easy and safer to work with or that require simpler tools to process. Or they make the product easier to assemble and move around on the plant floor. DFM engineers cannot put on blinders and focus exclusively on the manufacturing process, as a good manufacturability decision may have negative effects on another process. For example, the use of cheaper raw materials will lower the manufacturing costs, but may also result in inferior quality products. On the other hand, the choice of higher-grade and more costly materials that require special tooling will add manufacturing costs that will be passed on to the consumer. Product designers often face this type of dilemma: how to assess and balance design and manufacturing considerations that are, at least on the surface, at odds with each other, such as weighing the cost of materials against product durability, or how to justify more extensive product testing against the increased costs and a protracted time to market.

DFX is about carefully calculated tradeoffs. It is a total lifecycle design practice that takes into account the costs and benefits of each and every design decision in the different lifecycle phases of a product, considering both short and long term ramifications. For example, DFX affects the choice of raw materials that achieve a desired balance between material costs, manufacturing costs, reliability, environmental ramifications, and any number of additional consequences.

The design of a complex product requires that several DFX practices be applied in tandem. In addition to DFM, which is generally a well-understood process, there are several DFX disciplines that product companies need to consider.

Design for Supply Chain (DFSC): The design and architecture of a complex product should reflect the supply chain of the manufacturing and service of that product. Early interaction between design and supply chain is required to make build-versus-buy and sourcing decisions before design decisions are locked-in. This leads to further optimization and agility in the supply chain, and reduces the impact of the inevitable late changes and quality problems.

Generally, a modular product (personal computers being a prime example) should be supported by a modular supply chain--multiple sources of standard components. And a highly integrated product (e.g. automotive historically) should be supported by an integrated supply chain--suppliers of tailored components/sub-systems located near final assembly.

Design for Serviceability (DFS): Good design must consider the complex dependencies between product design, reliability, service, inventory planning and reverse logistics. Product failure rates dictate the frequency of field repairs. Product modularity defines field replaceable unit (FRU) or customer replaceable unit (CRU) levels and the optimal spare parts inventory that will be needed to support the desired service level. The frequency of repair and the type of parts replaced will determine the requirement of reverse logistics, depot repair, and part restocking.

Design for serviceability is a DFX practice that evaluates design modularity and supply chain alternatives in order to maximize serviceability and enhance the customer ownership experience with inventory and reverse logistics operations in mind. Failure to apply DFS principles results in products that are difficult to maintain, require long repair times, and encounter high rates of no fault found when they are returned for service. DFS is vastly underutilized by today's product companies, especially when considering the rising costs of servicing products and settling warranty claims. Many service organizations are transitioning to profit centers, but have little to no control over the failures and costs of repairing the products they are responsible for. Unfortunately, manufacturers of complex equipment do not usually consider diagnostics and service delivery until the design is essentially complete and handed over to the group responsible for developing service tools. Design decisions that impact failure rates and FRU levels are usually made very early in the design phase, before serviceability assessment takes place and supply chain and reverse logistics planning is initiated.

Design for Sustainability (Design for Compliance--DFC) : Compliance is critical to all manufacturers, ranging from industry-specific requirements such as ROHS and WEEE in electronics to TREAD Act in automotive, to corporate accounting regulations and overall social responsibility. Manufacturers take a broader view that applies corporate compliance throughout the product life cycle, not only to reduce risks and costs but also to increase profit and enhance competitive positioning. As manufacturers continue to outsource activities and operate across an elongated and more complex supply chain and, in many cases, act as brand owners more than manufacturers, they must ensure compliance throughout the ecosystem and assume surrogate responsibility for the actions of all their partners in the value chain, who may be operating in multiple geographies, and are held accountable for both global and local regulations.

In view of the criticality and pervasive impact of existing and emerging regulations, compliance cannot be an afterthought and companies must take it into account during design, manufacturing, shipment, servicing and decommissioning of products. Manufacturers that adopt a total life-cycle view of sustainability use a design for sustainability process to balance conflicting business drivers and weigh design alternatives that would provide the highest level of sustainability at an affordable cost. This allows all relevant participants in the product design and the supply chain to assess the impact of product-related decisions like material selection or maintenance practice on any and all regulations, and, because they are involved early in the process, they can identify compliance infringements and suggest design changes before any potential non-compliant design is locked in. DFC addresses the five main categories of sustainability: material selection, sourcing policies, demand and fulfillment, and end of life postponement. Design for sustainability stresses the need to evaluate alternative designs for sustainability alternatives: incremental costs of incorporating onboard capabilities versus the application of external tools to reduce environmental damage during operation and maintenance. For example, designers can assess the direct and indirect costs, hazardous waste, and emissions resulting from the use of photodegradable materials against the long-term environmental benefits of these materials.

Design for Warranty: Soaring warranty costs in many sectors call attention to the need to improve product quality and reduce repair activities that often exacerbate warranty costs. Manufacturers in industry sectors that experience high warranty costs often engage in design for warranty, using warranty information to identify weaknesses in product reliability and in service. One could argue that Design for Warranty is not a separate DFX activity and is more like applying warranty information as input for DFS and DFC.

Essential Guidance: DFX goes against the too common practice of focusing on short term cost cutting at the expense of reduced reliability, brittle supply chains and increased total cost of ownership. Those, in turn, not only increase lifetime costs that can potentially diminish the initial savings, but also increase total cost of ownership, create dissatisfied customers and tarnish brand image. Product companies should establish a DFX practice that extends throughout the product lifecycle. This starts as a product lifecycle strategy that recognizes that short-term savings are not always the smart decision--overall lifetime costs, quality and customer loyalty are. Therefore, DFX should not be implemented as a linear set of singular lifecycle phases but as a process that strives to harmonize the various needs and constraints of the different aspects of a product. As importantly, DFX must start early in the product lifecycle and continue while the product is in production. Organizations already familiar with value engineering could retrace the roots of that practice and apply similar principles to all phases and consideration of the product lifecycle, remembering, again, that the goal is to optimize the overall value and lifetime costs, including non-engineering considerations such as sustainability.

Product managers should be aware that like value engineering, DFX needs to be applied in the specific context of a product, its intended market, and the overall business environment. For example, the designed-in reliability of a product needs to be evaluated not only from the perspective of sale price and reliability of competitive products, but also considering warranty costs and the service offerings. Manufacturers should implement an IT environment to support DFX analysis and decision-making. An enterprise Product Data Management (PDM) platform is critical to provide a complete view of product information, which can be used at any phase of the product lifecycle to support what-if analysis and harmonize goals that may be at odds with each other in design, manufacturing and change management decisions. DFX spans multiple disciplines and involves a range of communities of practice and functions, each with their own technology and business needs and constraints. Manufacturing firms must establish appropriate inter- and intra-enterprise collaborative platforms that create knowledge transparency, improve decision-making, and enable corporate product strategy.
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