Page 20 - MetalForming December 2009

A New Day Dawns for this Wisconsin
Heavy-Metal Fabricator
D&S Manufacturing puts the pedal to the metal to increase the velocity at which parts and assemblies move through its 140,000-sq.-ft. plant, with impressive results to show for its efforts—improved on-time delivery, slashed scrap costs and customer rejects, and lead times cut in half.
BY BRAD F. KUVIN
Ahuge workforce-development ini- tiative coinciding with a major facil- ity overhaul has metal fabricator D&S Manufacturing, Black River Falls, WI, focused on increasing the velocity of its operations. “We’re adding speed through our plant,” says company pres- ident Michael Dougherty, “creating new opportunities to further reduce costs in areas such as inventory control, material handling and scrap and rework.”
D&S embarked on a mission late in 2006 to reinvent itself from a tradi- tional batch and queue process flow to a flow more suitable to its high-mix low-volume style. “We had no visual
triggers, no line-of-sight scenarios,” says the firm’s director of continuous improvement Frans Carlstrom. Being primarily a custom manufacturer of large-scale parts and assemblies for heavy-metal customers such as Cater- pillar, CNH, Oshkosh Corp. and the Trane Co., D&S sought a process to help it prioritize kaizen events, identify waste and provide greater visibility into its value stream of fabrication process- es, including laser- and plasma-cutting machines, vertical machining centers, press brakes, and four robotic arc-weld- ing cells. It found the solution by per- forming value-network mapping (VNM).
What’s a Value-Network Map?
“We took most of our parts that we process and divided them into three
categories—strangers, repeaters and runners,” says Carlstom. Strangers run infrequently, maybe once per month; repeaters run two or three times per month; and runners might hit the shop floor weekly, perhaps even daily.
“Dividing the product mix into groups allowed us to put them into process-flow families,” says Carlstrom, explaining how a value-network map comes together. “From this we were able to discover a better way to organize our machines and redesign our building layout, locating as many of our opera- tions as possible within line of sight. This allows us to then apply additional lean tools that use visual cues to trigger operations. We went from grouping jobs by weeks down to a couple of days to now daily groupings in how we get our materials and other resources.”
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At D&S, improving the flow of materials from its gateway work centers—lasers, oxyfuel and plasma-cutting machines—and into its fabrication area of press brakes, machining centers and the like, and eventually on to assembly and robotic welding cells, has helped the firm eliminate delays and waste in its material-handling operations.