Process Measurement, Scrap Reduction, and Performance Reporting
Today's growing emphasis on higher quality at lower cost
has caused manufacturers to look at creative ways to apply quality improvement
technology. This was the case with one of MAP Quality Engineering's privately
held clients facing excessive scrap costs. As the global leader in their
market, MAP's client needed to increase productivity to meet a growing
demand. But in a tight economic climate, they could not justify the capital
expense for new production equipment. Instead, they had to make better
use of the existing process and machinery.
Quality Improvement ObjectivesThe client identified two key project
objectives. First, reduce scrap levels of the assembled product. Scrap amounts
were running approximately 4000 square yards per assembly line per day.
Second, enable production schedulers to schedule production based on real-time
WIP inventory amounts.Manufacturing ProcessThe client has a centralized
manufacturing facility with several buildings housing different steps of
the process. In the first step, spooled wire is coated with PVC in the coating
process. After coating, the wire is drawn through an oven to cure the PVC
and is wound onto spools. In the final step of the process, the spools are
staged as WIP inventory for use in the assembly department.Strategy DevelopmentVariation
in coated wire diameter causes the majority of scrap in the assembly stage.
This fact drove MAP's strategic thinking. MAP's consulting engineers posited
that if spools of coated wire could be segregated according to their average
diameter and standard deviation, then the assembly department could pick
spools that met the specifications for the product they were assembling.
Measuring the diameter of the coated wire in real-time, as it was wound
onto the spool, could enable the assignment of a quality disposition. Tracking
the spools by disposition could also enable schedulers to monitor WIP and
adjust production accordingly.Strategy ImplementationA vision system
that allowed the measurement of the diameter of 80 wires being wound at
a rate > 60' per minute was identified and implemented. After fine-tuning
the data collection by the vision system, MAP engineers implemented Wonderware®
InTouch™ to crunch the data and to provide operators with a visual
summary of each spool and a corresponding disposition label. Based on the
disposition, assembly workers now pick spools that meet the quality requirements
for the product in production.InTouch was also used to manage the logging
of actual and summary data to a Microsoft® SQL Server® database.In addition
to reporting current quantities on hand, production schedulers wanted the
ability to analyze the data and to create statistical charts, in an ad hoc
manner, from remote locations. Therefore, Northwest Analytical® Quality
Analyst Web Server™ was chosen to facilitate WIP reporting. Production
schedulers are now able to schedule specific products based on the actual
coated wire inventory levels and production trends.Production managers also
used Quality Analyst Web Server to access manufacturing performance metrics
such as scrap rates and throughput. Client engineers are now able to identify
when substandard production has occurred, and they have immediate access
to data that help uncover assignable causes.
Quality Improvement ResultsIn total, the project required an investment
of approximately $250,000 U.S. dollars. While the necessary investment was
substantial, the results were fantastic! As explained by the client's project
manager, "Over the first three months, we observed a reduction in assembly
scrap from approximately 4000 square yards per assembly line per day to
an average of 250 square yards per assembly line per day." This calculates
to a 94% reduction in scrap.
The reduced scrap, in turn, reduced the amount of "rescheduled production."
This effect resulted in a throughput gain calculated at 5% " …which
is a significant amount of product when you consider the total volume produced
each day!"The projected annual savings, with the new system deployed
to the other manufacturing lines, are estimated at ~$1.6 million U.S. dollars.About
MAP Engineering:MAP is a consulting firm specializing in the integration
and utilization of statistical tools for process improvement. To contact
MAP, please visit www.mapqe.com
or call 1-877-SPC by MAP.About NWA:NWA is a leading provider of analytical
software for statistical analysis. NWA's tools for on-line SPC and off-line
SQC are HMI/SCADA independent. To contact NWA, call 1-888-692-7638.About
Wonderware:Wonderware is the world’s leading provider of HMI software.
To contact Wonderware, please visit www.wonderware.com
or call your local Wonderware |
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