For Hamilton Sundstrand, providing aerospace systems and components to customers like Boeing is no flight of fancy. A subsidiary of United Technologies Corporation (Windsor Locks, CT), Hamilton Sundstrand is among the largest global suppliers of technologically advanced aerospace and industrial products, designing and manufacturing aerospace systems for commercial, regional, corporate, and military aircraft, as well as supplying NASA and international space programs.
Within Hamilton Sundstrand''s multiple business units, the company''s Aerospace Division is taking flight with an aggressive quality assurance methodology called Achieving Competitive Excellence, or ACE, a comprehensive process improvement methodology that is UTC''s strategic way of doing business. An integrated approach to quality improvement driven by consistent and measurable goals, ACE focuses on such activities as 5S or workplace organization, total predictive maintenance on factory and office machines, root cause analysis in both product and process, mistake-proofing causes of variation, and Process Certification, the variability reduction arm of ACE.
Process Certification, which is implemented internally at Hamilton Sundstrand and externally at their suppliers, uses VisualSPC (Statistical Process Control) software from CimWorks, a GE Fanuc company, to monitor and control key characteristics for new and existing products and processes that drive critical customer requirements. Process Certification is an outgrowth of Hamilton Sundstrand''s implementation of Boeing''s D1-9000 Advanced Quality System (AQS) requirements. The goal of Process Certification is to reduce variability in crucial process inputs that affect the variability in key characteristics. This focuses on the processes that result in products that meet, and often exceed, customer requirements. Meeting with soaring success, Process Certification has helped to achieve vastly improved customer acceptance rates while providing dramatic reductions in scrap, rework, and repair (SRR), cost of quality (COQ), and cost savings and avoidance.
Providing Quality Inside and Out
After years of experience working with and using CimWorks quality solutions, Hamilton Sundstrand selected VisualSPC to provide the real-time process information, data collection, analysis, and reporting needed to implement Process Certification. In addition to CimWorks'' history of quality and outstanding support at Hamilton Sundstrand, the software''s flexibility in setup and gage connection was a key consideration in this decision, as Hamilton Sundstrand connects gages to many different applications throughout its Aerospace Division Manufacturing facilities. Designed with the operator in mind, VisualSPC also offered Hamilton Sundstrand a user-friendly setup interface that significantly reduced implementation and operator training time. In place since 1998, VisualSPC has been a great success from the supplier, business, and user perspectives.
Similar to Six Sigma quality processes, Hamilton Sundstrand''s ACE Process Certification is a prevention-oriented system that has been implemented internally as well as externally at the company''s suppliers. Like Six Sigma, Process Certification identifies critical-to-quality (CTQ) and other key characteristics that are monitored and analyzed using VisualSPC. Process Certification also employs Certified Quality Engineers, similar to Six Sigma "Black Belts," who are responsible for implementing new manufacturing tools and practices from day to day.
Hamilton Sundstrand also implemented Process Certification at the supplier level, requiring that products brought into the plant for further manufacturing be held to the same quality standards as those produced on site. "If you consider that we purchase 80 percent of our parts, you can see the significance of quality assurance at the supplier level," notes Peter E. Teti, Process Certification manager. "When suppliers are able to demonstrate that they can meet Hamilton Sundstrand''s process control and capability requirements, we can receive material from them without additional oversight."
According to Teti, Hamilton Sundstrand suppliers who participate in implementing a process control approach like Process Certification have achieved a 200 parts per million (ppm) defect rate as compared to an average 15,000 ppm for non-participating suppliers.
Proving the Process
VisualSPC is designed to reflect plant floor processes. The Windows™-based software incorporates extensive capabilities that provide the flexibility and control required for data collection, analysis, and reporting. Easy-to-read graphics provide instant feedback about a process, and operators can evaluate variation in measurement systems. A handy importer allows engineers to import data from their coordinate measuring machines, output in ASCII files, directly into VisualSPC''s standard Microsoft Access® database, while VisualSPC facilitates the monitoring of production floor activity from a PC on the plant''s Ethernet network. Histograms, control charts, Pareto diagrams, and other charts also provide detailed information.
Using VisualSPC, Hamilton Sundstrand enjoys networked real-time data collection and analysis with over 1,000 key characteristics being monitored throughout factory cells. Operators at Hamilton Sundstrand''s Windsor Locks mechanical systems facility are responsible for the one-step data input that triggers automated chart generation on individual PCs set up at stations alongside their machines. At the shop floor level, VisualSPC provides a window into company processes like turning, boring, and grinding via a variety of chart options that follow the key characteristics input by the operators. From the graphic displays, operators are instantly alerted to process changes and problems and can quickly adjust the process specifications or enlist engineering assistance as needed.
At Hamilton Sundstrand''s electronics plant in Farmington, CT, VisualSPC generates a special DPMO (defects per million opportunities) Chart, incorporating features that CimWorks designed specifically for Hamilton Sundstrand. The DPMO Chart is an attribute chart used for focus on processes as opposed to product. The DPMO concept involves normalizing the complexity of different assemblies processed by the same equipment (e.g.; identifying opportunities for defects in the wave soldering process). This feature allows the use of one chart for the process where a chart for each part number was required. It also keeps track of part numbers and any other traceability data considered important by the customer and will allow the generation of charts for each individual part number.
One of the best features of the DPMO chart is that it develops a defect Pareto diagram that is instrumental in understanding and prioritizing root cause analysis of defects. All the information gathered is displayed on a single, comprehensive screen without the back-and-forth, multi-screen burden typically associated with multiple-characteristic analysis. Operators can cut and paste DPMO charts and send them to engineers over the network. They can also input "assignable causes," which refers to such process events as circuit board design changes that further assist in purifying a process.
"Our operators are very motivated by the freedom of control, and they know what to expect in the process," Teti says. "CimWorks understood the needs of our electronics operation and created a powerful tool that truly streamlines the process setup."
From a quality engineering standpoint, VisualSPC provides preventive information for new processes and reactive information for existing, mature processes. Preventive process control analyzes new processes by reviewing similar programs and operations with the goal of avoiding warranty claims and assuring reliability. For new processes, engineers can analyze "what might be" and use the software as a prediction tool for creating new blueprint tolerances that are producible from day one, thus avoiding scrap, rework, and repair activities. Reactive process improvement tests an existing, mature process to drive down SRR and reduce labor variation. Engineers can input key characteristic data, allowing VisualSPC to track the outcome and determine the success of the process using advanced statistical analysis.
In Hamilton Sundstrand''s disk and shaft area, for example, operators perform finished turning work while tracking two key characteristics: inside diameter and outside diameter. VisualSPC assures the maintenance of these process outputs during manufacturing to produce a tight tolerance of +/- .0005 of an inch. Similarly, key characteristics for the heat exchanger core produced for Boeing, Lockheed-Martin, Embraer, Northrop, and other customers focus primarily on core height. Inspectors can watch from their PCs as the software performs six automated readings, tracking results to meet Hamilton Sundstrand quality standards, which are even more rigorous than the customer requirements. Core height tolerances are set on average at +/-.080 of an inch. By controlling the detail fins and closure bars (which are stacked in layers that ultimately result in the final core height) to a +/- .001 tolerance using VisualSPC, the final core height can be controlled to a +/- .015 tolerance. This has relieved the company of the additional rework, trimming, and fitting they experienced prior to introducing Process Certification with VisualSPC.
Propelling Improvement
The implementation of VisualSPC within Hamilton Sundstrand''s ACE Process Certification initiative marks a tremendous achievement in customer service with a near-perfect acceptance rate of 99.96 percent for Boeing systems -- a 60 percent improvement. Likewise, overall customer acceptance rates have increased 30 percent, while the company has reduced its SRR by 30 percent over the year. Supplier Process Certification initiatives add to the impressive outcomes with a 30 percent reduction in lead times accompanied by a 40 percent increase in quality.
"VisualSPC is helping us achieve the goals of ACE with significant decreases in SRR and warranty claims, as well as increasing quality and improving customer relations," Teti observes.
To date, more than 40 sites within Hamilton Sundstrand''s Air Management System plant are using VisualSPC. Ultimately, Teti hopes to implement the software in every business unit within the company to share process data and link similar processes to form a process database. Currently, the company is implementing Process Certification with VisualSPC into test sites within its Environmental Control Systems, Propellers, Mechanical Engine Systems, and Flight Systems divisions, striving for another 30 percent reduction in SRR.
"The results speak for themselves," Teti says. "Process Certification with VisualSPC has completely revolutionized the way that we reduce process and product variation, and it''s this ability to make products better than blueprint that gives us an unmatched edge over our competition."
How Engineers Use SPC Data: An Example
Hamilton Sundstrand engineers not only collect, analyze, and report data using VisualSPC from CimWorks, they also document how they improve their manufacturing processes based on the SPC data. For example, Certified Quality Engineers (CQEs) in the Special Process Area recently selected sulfuric acid concentration level as a key characteristic and started recording these levels and monitoring the data in VisualSPC. After entering historical data, the engineers noticed two occurrences in the X-Moving Range chart that looked unusual, even though none of the points were out of the control range. They noticed that concentration levels seemed to stay fairly consistent, then drop suddenly -- not enough to cause out-of-control points, but enough to merit further investigation. They also noticed that, whenever a drop occurred and they added more concentrate, the concentration level did not rise as high as it was before the drop.
After some investigation, the engineering team discovered that the sudden drops were correlated to the addition of dry ice to the solution. Now, when dry ice is added, operators know that they also need to add concentrate to offset the drop in the concentration level. After talking to operators, the team also learned that the amount of concentrate that the operators add is not an exact measurement. Knowing that they can always add more concentrate, operators normally add less than needed to make sure the level does not rise too high because, if the level exceeds the height limit, the operator has to perform a tank dump. As a result of these findings, the Special Process team was able to justify the purchase of measurement equipment that will enable operators to add precise amounts of concentrate, thus allowing them to bring the levels back to their original levels more accurately and enabling Hamilton Sundstrand to provide yet another level of quality assurance for their customers.