Original Date: 04/07/1997
Revision Date: 04/14/2003
Information : Statistical Process Control
Prior to 1982, Rock Island Arsenal’s (RIA’s) manufacturing operation relied on a detection/segregation type quality program. Although this method of establishing process dimensions to limit variation was used by industry for many years, it was expensive and ineffective due to high nonconforming material rates and untimely corrective actions. Parts were produced, defective parts were identified and dispositioned, etc., and throughout this cycle, the movement and/or storage of parts were required.
The adoption and expansion of statistical process control in RIA's manufacturing operation were administered by its Quality Assurance organization during the 1980s. Implementation and development of the program included the training of employees, automation of data collection, and acquisition of statistical analysis software. These steps were significant improvements and initiated RIA's transformation to a prevention type quality program.
As a result of RIA's participation in a customer established certification program, two significant developments occurred in 1992 and 1993. In 1992, SPC training was expanded to include statistical techniques as a tool for reducing variation in administrative processes. This detailed, application-specific training helped win support as others saw the value of the program. Another enhancement occurred in 1993 when the ownership of SPC applications in the manufacturing operation shifted to Planning/Production. With this development, manufacturing replaced Quality Assurance as the organization responsible for identifying SPC applications, and an enhanced level of process owner buy-in was established. The current structure is as follows:
SPC Coordinators provide technical support, administer training, and interface with management.
Process Planners identify SPC applications and submit requests for reduced inspection.
SPC Leaders provide floor-level technical support, analyze process capabilities, and calculate control limits.
Quality Engineers review process capability analyses and provide technical support to Planning/Production.
Facilitators set-up/download automated data collectors and facilitate SPC applications at the Cost Center level.
Machine Operators monitor processes using SPC techniques, maintain process stability, and document process improvements.
Quality Information Technician maintains the capability database, distributes customized reports, and summarizes data for management review.
As of March 1, 1997, 1,246 active characteristics were identified for SPC at RIA. Since 1993, the benefits obtained from the improved system include a 21% reduction in the overall manufacturing defect rate; and for two specific production items, 73% and 79% reductions in variation. In addition, a benefit was realized when the SPC team applied the principles to its own task and reduced the SPC data cycle time by 70%.
For more information see the
Point of Contact for this survey.