Design for Manufacturability (DFM) is a design doctrine that seeks to minimize costs and optimize process stability. This approach to product development focuses on designing parts, assemblies, and systems for efficient, reliable, and low-cost production. Rather than treating manufacturing as a downstream step, DFM brings manufacturing considerations into the design phase—where the majority of cost, complexity, and risk are ultimately determined.
DFM can be accomplished in a variety of ways. The best approach will vary based on the manufacturing process (such as machining, molding, or assembly), the organization’s capabilities, and the specific product requirements set by the customer. As a result, DFM is not a rigid checklist, but a set of guiding principles that must be applied with an understanding of both engineering intent and manufacturing reality.
This article outlines the core principles of DFM and explores its measurable benefits, including cost reduction, improved process stability, higher quality, and faster time to market.
At its core, DFM strives to simplify designs and the processes used to manufacture those designs. The key areas where these benefits are realized are cost reduction and process repeatability.
DFM targets cost reduction by minimizing the following:
In addition to cost reduction through simplicity, DFM can increase process stability and repeatability, improving quality and further reducing cost. Principles such as Poke Yoke (error proofing) are best implemented at the design stage by ensuring the design lends itself to proper assembly. For example, designing parts that can only be assembled correctly by having fasteners and assembly features that permit the assembly to fit together only in the correct orientation.
DFM also places a focus on the reduction of assembly steps or operations. This decreases defect opportunities and also reduces storage and travel time through the manufacturing facility. Furthermore, simplicity in design and process flow lends itself well to automation. Simplified, standardized, or consolidated processes are generally easier to automate than complex processes. There are certainly other considerations when implementing automation, such as expected production volume and ROI potential, but designing parts to be automation-friendly and cost-effective can significantly reduce labor costs and improve process repeatability.
Design for manufacturability should start early in the design process. It should seek to align design goals with manufacturing capabilities. This varies for every organization; leveraging existing capabilities may not be feasible in every design case. Strategically aligning the growth of manufacturing capabilities with the design process enables rapid adoption of new production methods and technologies. This leads to quicker ROI and an accelerated learning curve when new processes, machines, and work centers are implemented.
Many companies easily realize manufacturing success with familiar, proven, and stabilized processes. Design teams must be aware of these existing processes and grasp how best to utilize them in new designs. It is also important to understand the limitations of existing processes as well as the long-term strategic goals of the manufacturing organization.
The DFM process is not intended to be linear, but rather a cycle of continuous iterations optimizing designs as manufacturing results are realized from prototype and low-rate initial production (LRIP). Periodic review of production results and data is critical to continued success as manufacturing volume increases. Lessons learned should be incorporated into the design and manufacturing processes wherever possible.
The best part is no part. This maxim must be followed to fully optimize a design for manufacturing. Every additional part, no matter how small or seemingly insignificant, adds cost, complexity, and opportunities for defects. Design teams must strive to remove all unnecessary parts, while also not compromising the design objectives and performance goals. This is sometimes called “undesigning,” which may sound counterintuitive, but in addition to the cost benefits of removing unnecessary parts from a design, this approach drives Lean thinking among the design team. This can lead to pleasant side effects that are important in some applications, such as reducing the product weight.
Similarly, the best process is no process. The same approach that is taken to “undesign” an assembly should also be used for the assembly process. Unnecessary procedural steps should be removed. Necessary steps must be consolidated to minimize travel, storage, and other wastes. Specialization and unique processes are the enemy of DFM. They should be identified early and eliminated wherever possible.
Another method used to design for manufacturability is to leverage proven designs wherever possible. In addition to diminishing the learning curve, this can minimize the upfront setup costs for various manufacturing processes. For instance, using a shared PCB design in a box build can eliminate the time needed to program that PCB on various assembly and test equipment. This can also apply to CNC-milled parts, molded parts, etc.
Simplifying the geometry of parts is another way to reduce complexity. This may not apply to all parts and processes; however, in most cases, simple geometry reduces the cycle time to create the part, the complexity of the initial programming and/or setup costs, and the risk of defects. For example, it may seem obvious that a CNC-milled part would see reduced setup costs, programming costs, and cycle time if the geometry were as simple as possible. It may not be as obvious that even a molded or stamped part would also benefit from simplified geometry. In the case of a molded part, simpler geometry may reduce the cost of the mold. In the case of a stamped part, simplified geometry could reduce tooling costs and the number of operations required to create the finished part.
Standardization of common parts and common designs is another method that can be used to increase the manufacturability of an assembly. Depending on the complexity of the design, this can manifest in several ways:
Modularity is another consideration that can decrease cost and complexity in manufacturing. Implementing modular designs with common sub-assemblies or manufactured parts can net similar benefits in the production environment to the benefits that standardization brings to the supply chain. Common manufactured modular parts can be more easily planned, manufactured on existing lines, and stored. Modularity may enable the implementation of Kan Ban or safety stocking systems when common modules are designed into a wide variety of product lines. This can also minimize many of the challenges seen in high-mix, low-volume manufacturing environments. By implementing common modular designs across a wide range of products, manufacturers can realize the benefits of higher-volume production runs even if the final product is low volume.
Design choices made early in development largely impact manufacturing outcomes. Decisions around part geometry, tolerances, and assembly methods influence cycle time, tooling complexity, defect rates, and supply chain requirements.
At Advanced Conversion Technology (ACT), we’re vertically integrated, which means we design and manufacture all of our products under one roof. Our design team works closely with our manufacturing team to ensure that products are designed with manufacturability in mind early on in the process. Our design process includes multiple stage gate design reviews that involve manufacturing experts as well as the core design team. This addresses these factors upfront, helping to avoid costly redesigns, production bottlenecks, and any quality hiccups later in the product lifecycle.
We also align our strategic manufacturing capability expansion plans with the design and business development teams to ensure that new designs are leveraging our latest capabilities and growth opportunities. This collaboration and focus on manufacturability allow us to respond rapidly, maintain direct control of production capacity and priorities, and significantly reduce development time.
Let’s partner in power! Contact our expert staff today.
