New Software Improves OD Tolerance
The company began using SPC Express software from Major Micro Systems (MMS, Southfield, MI) to evaluate its manufacturing processes. “We were already using in-line OD measuring devices but we did not have the tools to fully analyze the process,” says Ron Mooneyhan, regional quality engineer for Sonoco. “The end result was that we were not meeting our customers’ desired results.”
Come a long wayIn the early 1980s, Sonoco (Akron, IN) used monitoring equipment to display single outside diameter (OD) readings on a small processor screen. The only feedback to the manufacturing crews was various warning lights that would notify the crews if the process was going out of control. “With no immediate feedback on process trends or out-of-control situations, there was no sense of urgency to use the unit to eliminate variation,” says Mooneyhan.
To collect SPC data on the core being produced, a crew member had to manually measure the core and record the measurements on a control chart, plot the readings on an X-bar and range chart and complete the traceability information. There was no real-time output on trends or on how close the process was to the upper or lower control limits using the manual system.
As part of the improvements, Sonoco purchased a new processor that had a video display output that could also transmit SPC data. With the new processor, manufacturing crews could now monitor measurements and make real-time adjustments as necessary. While this was a significant step, the company determined that statistical process control could further improve the process.
The task was to find an SPC software package that would interface with the OD monitoring processor. The SPC software package needed to download the core parameters when changing between different core sizes, as well as collect the measurement data from the processor output.
Tried and trueMooneyhan looked at the SPC Express software program that was already in use at another Sonoco plant. The manufacturer of the monitor shipped MMS, a monitor similar to one in use already and the software supplier customized its software to match Sonoco’s needs. “The feature worked correctly the first time we loaded the software,” says Mooneyhan. “That sold us on the product and the tech support.”
SPC Express is used to set up data collection files, called Part Files, by individual customer and location. Within each Part File, individual tube size files, called characteristics, are set up. Within the characteristics file is a reference to the OD file that will be downloaded after the tube size is selected.
When a new production order is set up, the operator selects the customer and location of the product to run and the core size to be manufactured. After selecting the core size, SPC Express downloads the predefined OD file to the OD monitoring device. Included in the downloaded OD file are upper and lower control limits. When the production run is started, the OD monitoring device outputs sample readings throughout the production run to SPC Express. This data is collected and displayed in an X-Bar and range chart format on one side of the operator’s computer screen. This not only allows the operator to view trends, but the operator can readily see data on previous shipments, because all data is maintained in individual customer data files. Additionally, traceability fields are displayed on the split screen that allow order information input. This is useful in being able to match production data to the production order being produced.
If a process goes out of control, a pop-up screen appears. The operator inputs the cause of the out-of-control situation along with the corrective action that brought the process back in control. The out-of-control information is automatically written to a separate data file that is later analyzed by quality technicians and used to eliminate nonconformance. “This is a key part of our quality efforts,” says Mooneyhan. “It helps promote continuous improvement in our operations.”
SPC Express allows the quality technician to create the data files with a predefined target for the desired core’s OD along with applicable control limits. This ensures consistent setup parameters, which are available to the line operator electronically, without having to manually input the data or recap on a manual control sheet. With selection of the core size, the applicable OD measuring processor is downloaded with the correct parameters. The crews can now watch the process and are able to denote trends and determine if corrections need to be made to the process. If the trend shifts are because of normal variation, crews know that the process will come back to target. This helps eliminate variation because continual adjustments can lead to greater variation than letting the normal process run it course, says Mooneyhan. “The crews have also learned a lot about our raw materials used in the process by watching trend lines and realizing that normal variation is just part of the process,” he says. “They have become trend managers.”
The software helped Sonoco reduce customer issues because the company is providing a more consistent product. Sonoco now uses the software in all production areas to record SPC data on key aspects of the product that they produce. It has also eliminated manual control charting within the production plant. Setup time and downtime were reduced during the manufacturing of the product. This has led to lower scrap, improved machine capability and reduction of product rejections—a truly cost-effective solution.
In addition, most of Sonoco’s measuring equipment is linked directly to the data collection program. The product to be measured is placed in the measuring device and with a push of a button, the data is automatically sent to the data file along with the traceability information.
For customers requiring QS- and ISO 9000 registration, Sonoco can now provide customers with SPC data to support their quality efforts. Many customers now request histograms as their Certificates of Analysis (COA) or Certificate of Conformance (COC). With a click of a button, a histogram can be printed from a particular production run and forwarded to the customer by e-mail, fax or sent with the shipment.
In addition, the SPC Express program is used to collect causes of scrap. With the Attributes file creation feature in the program, Pareto charts can be generated for the time frame desired or, by using the traceability fields, query a further refinement of the analysis.
For Mooneyhan, one of the best benefits of the software is its networking capability. “My computer is mapped to each of the plant’s SPC data file servers. During computer boot-up, I know if each individual SPC data file server is up and running,” he says. “If not, the plant can be contacted to see if there is a problem. Additionally, if they need assistance in creating new files or looking at a problem with a file, I can create or look at the file from my computer and make the corrections. The advantage is that I can be of service without having to physically visit the plant.”
Major Micro Systems Inc.
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- Parameters can be automatically downloaded when changing between different core sizes and collect measurement data from the processor output.
- A predefined OD file is downloaded to a monitoring device that includes upper and lower control limits. Production data is collected and displayed on the operator’s computer screen in an X-bar and range chart format.
- If the process goes out of a control, a pop-up screen appears.