SPC Produces Big Savings at Steelcase
Steelcase has traditionally tracked millage based on average paint thickness, without giving major consideration to variation, notes Paul Dzwonek, quality engineer in the company's Office Systems plant in Grand Rapids. As a result, while Steelcase consistently maintained average millage at levels that kept customers happy, the company often applied more paint than was necessary. "Each color has a basic minimum heighting millage that we want to hit, so we would typically put on more to make sure that we hit that minimum customer requirement," Dzwonek explains. The result: significant excess paint costs for Steelcase.
That began changing about two years ago, however, when Steelcase acquired new statistical process control (SPC) software called the Statistica Enterprise-Wide SPC System (SEWSS), provided by StatSoft Inc. (Tulsa, OK). The software was acquired as part of a Steelcase enterprise-wide initiative to standardize on statistical software as a process improvement tool.
One of the first projects chosen for the initiative involved a liquid paint line and two powder coat paint lines at the Office Systems plant. On these lines--used for painting desk drawers, pedestals and other components--parts go through a two-stage process; human operators spray portions of the product, and the remaining portions are covered in an automatic spray booth.
For the project, paint line operators initially used film thickness gages to collect millage data on painted components after the paint had dried, and then used personal computers to enter and record the data. The data was analyzed using the SEWSS software by a project team including the paint superintendent, the finishing tech engineer and quality assurance personnel. When the data showed significant variation in paint millage, the team used various SEWSS tools to understand the sources of the variation and to help develop methods to improve the process.
A variety of process improvements were introduced, says Dzwonek. These included the addition of movable, height-adjustable platforms for use by operators during the manual part of the process, as well as a reduction in the number of spray guns in the automatic booths. In addition, operators were provided with gages that allow them to check millage of paint in the wet state, immediately after parts are painted, instead of after the paint has dried.
The latter change "probably had the biggest impact of all," says Dzwonek, by enabling millage variations to be caught and corrected almost immediately. "With this wet-film thickness gage, the product comes out of the spray booth and operators can test it right there, and they can make adjustments right away," he explains.
In the end, the project was "a tremendous success," Dzwonek says. The average paint millage on one powder coat line was reduced by 15%, and the variation was reduced by 40%, he notes. While the paint process continues to meet customer requirements for paint coverage, the process changes produced significant savings for Steelcase by eliminating wasteful paint overages. Indeed, according to Dzwonek, in just the first year following the process improvements, the Office Systems plant was able to document material savings of more than three times its total investment in the SEWSS software, training and implementation services.
The paint millage project was one of several early Steelcase uses of the SEWSS software, says Chuck Pergler, Steelcase project manager for process qualification. So far, four out of 15 Steelcase North American plants are using the software, he says, with expanded use planned.