by John Gilligan and Nick Dewhurst Boothroyd Dewhurst, Inc.
By its very nature, research is an upfront effort. Those who practice it best understand how critical it is to quantify new advances early on before applying them in full product development. In the field of manufacturing, the research role is changing. It’s increasingly spread-out among designers, analysts and managers once exclusively responsible for development. Credit some of this change to how closely, and early, that CAD, FEA multiphysics and PLM tools converge to capture geometry and simulate the performance of designs and materials. But acknowledge also that the trend away from dedicated, separate research is occurring because of perceived budget and time-to-market pressures.
Is the current approach of compressing research into development working? The short answer is yes; products are improving and goods are getting to market more quickly. But how can companies continue to build better products and make even stronger use of integrated digital systems? What’s still largely missing from the R&D equation is quantitative costing and the remarkable collaboration that can result from it.
Many people view costing as if it were a 19th century practice. It’s mostly done through late-stage supplier bidding or by price-referencing past designs. When numerical models are used, they’re generally rudimentary material weight- and volume-based estimations. This all comes near the end of the development process, a step before launch, and rarely influences decisions about redesigning features or substituting different materials and processes. But costing should be ideally started before designs are locked down into details and simulations that teams may not question or repeat because of perceived time constraints.
View of the pilot arc controller, which is a subassembly in the power supply unit. The original subassembly (left) had 88 parts. For the DFMA redesigned HPR130 (right), Hypertherm engineers cut the number of parts to 16.
Why upfront costing matters
Engineering teams today are concentrating overwhelmingly on functionality and time-to-market. Of course, products must work fully, meet high customer expectations, and be introduced when demand is highest. Paradoxically, though, in not deploying early, science-based costing during concept phases, teams further lengthen the detailed design and supplier negotiation stages. This wastes time that could otherwise be devoted to exploring design alternatives and improving functionality. It also delays launches.
The solution to easing this cycle is use of Design for Manufacture (DFM) and Design for Assembly (DFA) techniques and software. DFM today is an umbrella term for all DFM/DFA programs related to ease of manufacture and assembly. These range from CAD-based producibility software for sheet metal and molding, to rules-based handbooks and in-house cost/time studies captured in spreadsheets.
Whatever mix is used, it’s important to apply DFM methods and software early, and in conjunction with quantitative cost analysis. This allows more resources to be focused on product performance and profitability and drives resources back into the true R&D function: exploring design trade-offs and alternatives, with an eye toward trouble-free manufacturing and on-time delivery.
What the hard numbers can provide
Quantitative DFA is a set of questions—attached to assembly time and labor tables—that when answered serve to guide engineers to reduce product complexity by consolidating parts into unified, multifunctional designs. Product simplification is key to eliminating unnecessary parts and processes that devour organizational resources. Each part removed from a product configuration saves in CAD and PDM documentation, inspection, inventory, part tracking, ERP/BOM/MRP, supplier management and general overhead.
Efficient assemblies improve factory floor utilization, production throughput, quality, and landed costs, such as shipping, warranty and service. Survey results spanning more than twenty years also reveal an outstanding 42 percent average reduction in labor costs for DFA analyzed products. What would be the impact of that improvement alone for manufacturers seeking to produce within their primary domestic markets and avoid offshoring?
DFM analysis, often known as “should costing,” is a companion approach to DFA and allows the design engineer (often the central person between requirements creation and procurement) to quickly judge the cost of producing a new design against the original model. Working alone, or in a cross-disciplinary team, comparative trade-off studies can be done in DFM that select among the most feasible shape-forming processes and then determine the ideal material, process and manufacturing sequence for the given geometry.
DFM isolates overly expensive features (bosses, bevels, radii…) for redesign consideration, and accounts for secondary operations (deburring, polishing…), cost by volume, set-up times, and waste. This valuable information allows teams to avoid subjective opinions and do authentic “what if” exercises. Outside quotes and expert input are quickly reviewed with transparent DFM databases, bringing in suppliers as well for an early, faster and more dynamic design-review system.
Part interfaces are a traditional source of quality failure in products. Elimination of separate parts into single, unified assemblies helps reduce stress points and improve performance and durability. Using Boothroyd Dewhurst DFMA on a prototype transducer housing for the energy industry, Dynisco eliminated 18 parts and fasteners. FEA test results (above) reveal a corresponding improvement in quality throughout the cast housing, which must endure stray hammer blows in the field that occur in the routine sealing of a locknut mechanism.
Making the business case for using DFM.
Improving functionality, shortening time-to-market and reducing costs go hand in hand. Hypertherm Inc., the world leader in plasma metal cutting technology, undertook their DFMA program with a five-year plan to transform both product performance and cost. Research, development and manufacturing are all grouped together in their Hanover, N.H. headquarters. In terms of R&D, Hypertherm product development teams interact closely and, like most others in U.S. manufacturing, share a research function.
With the goal of continuous improvement, the company undertook the redesign of its leading plasma cutter as the first project. Their director of engineering, Dr. Mike Shipulski, an expert in Lean and Six Sigma, sought clear engineering and business progress. A multi-disciplinary team was gathered (because what would take place would affect everyone) and designers were asked to visit the factory and disassemble the previous system. Together they set an aggressive benchmark. With a DFA analysis of structural efficiency as a guide for brainstorming and measuring, they reduced half of the 1000 parts in the system.
In the new plasma cutter, named the HPR130, system subassemblies took 45 to 89 percent less time to put together. Assembly floor space availability increased by 40 percent. Warranty cost decreased 83 percent. Cost savings accrued to $5 million over 24 months, helping the company achieve record earnings that year. A new modular design approach derived from the project enabled standardization across the entire product family.
This image shows a series of cost curves for making the sheet metal end plate pictured at left. The Boothroyd Dewhurst DFM analysis compares five different sheet metal tooling options and shows how costs vary depending on the life volume planned for the part. At a life volume of 25,000, the least expensive manufacturing strategy utilizes a turret press. As volume increases, however, the analysis shows that other processes become more economical.
Most remarkable were the results as measured by the initial five-year redesign plan. Across several product lines, Hypertherm achieved a 600 percent increase in profit per square foot of factory floor space; warranty cost per unit declined more than 75 percent in that period; and unit labor expenses fell by 50 percent. The company is seeing success in both up- and down- markets and enjoys strong cost-to-performance ratios in its products.
As Hypertherm and many other companies know, DFM/DFA tools and techniques complement emerging PLM technologies in advancing product excellence and breaking down walls.
Continued success for R&D departments involves understanding and exploiting the dynamic relationship between product design, production efficiency and profits. The role of R&D in product development is to not only advance functionality, but to fully comprehend the impact that design decisions have on the extended organization and its customers. Structurally efficient, simplified designs, achieved through DFM/DFA costing and redesign methods, ensure that problems downstream are prevented and that financial resources are preserved and repurposed for further product improvement.