You have probably seen it yourself: images of Chinese workers toiling in mud-floored factories, each feeding a separate punch press, as if part and parcel of a living, progressive die. The lure of this cheap labor has sent many U.S. manufacturers scrambling overseas to cut production costs.
Although design-for-manufacturing tools that would have made this exodus unnecessary have been around for more than 20 years, companies continue to overlook them, says Mike Shipulski, chief engineer of plasma-cutter manufacturer Hypertherm, hypertherm.com, Hanover, N.H. “Companies are sticking their heads in the sand. Many U.S. firms have become too entrenched in doing things the same way. For example, a typical product-cost breakdown shows material to be the largest cost at about 72%. Overhead is around 24% and labor is only about 4%. The question becomes, why continue to move manufacturing to so-called ‘low-cost countries’ to chase 50% labor reductions for a whopping 2% cost reduction? And it’s sillier than that because companies don’t account for cost increases in shipping and quality control.”
The problem is that companies neglect to efficiently account for cost during the design side of product development, says Shipulski. “It is possible to slash costs during design that would realize large, discrete improvements, not just small, continuous changes, as in manufacturing.” he says. “To do this, companies should practice what I call ‘discontinuous improvement’ techniques, which lie at the heart of innovation. Although probably familiar to many, companies have not exploited to their full potential techniques in the form of Design for Manufacturability (DFM) and Design for Assembly (DFA), or DFMA. They provide quantitative ways to cut material costs and simplify assemblies, without affecting part function.”
Shipulski says Six Sigma and lean manufacturing work well on the production floor to reduce part variation and streamline manufacturing processes. “The approaches are valuable and, in fact, have helped companies stay in business through the recent downturn. Problem is, they focus solely on minimizing. Each method involves small, continuous improvements in labor costs and throughput. Manufacturers have neglected the biggest piece of the puzzle. They should be using DFMA in the design phase and introduce a low-waste design into production. From there, the well established lean manufacturing engine can further reduce waste.”
Just as mechanics need tools to fix cars, designers need tools to implement DFMA, says Shipulski. Software from Boothroyd Dewhurst, dfma.com, Wakefield, R.I., provide tools in the form of two complementary programs, Design for Manufacture (DFM) and Design for Assembly (DFA), each named after the method.
DFM comes in handy by letting engineers easily investigate the feasibility of using unfamiliar materials and manufacturing processes to produce more economical designs. The software helps quantify manufacturing costs for competing design alternatives. It also provides a guide for selecting materials and generates piece-part and tooling cost estimates at any stage of product design.
DFA, on the other hand, provides a quantifiable way to identify unnecessary parts in an assembly and determine assembly times and costs. This analysis suggests part-reduction strategies such as incorporating several features into one part. The outcome is a more elegant product with fewer components. This results in lower part costs, better quality and reliability, and shorter development cycles.
“Design engineers like DFMA software because it is straightforward to use and data-driven in terms of seconds and dollars,” says Shipulski. “At Hypertherm we used it to slash costs by 45% and cut assembly times by 50%.These kinds of savings are not unusual, so the software pays for itself quickly.”
Hypertherm Inc., www.hypertherm.com