Air Gages Validate Spindle Interface Components Advanced Machine and Engineering (AME, Rockford, IL) has been a customer of Stotz USA LLC (Freeport, IL) for a long time. Today, these two market leaders maintain a great working relationship, for all the right reasons. AME demands the highest level of quality in their machining and finishing departments and Stotz air gaging systems facilitate the accomplishment of that goal, every day, according to AME service manager Greg Hobbs. “Air gaging is the only technology we’ve found that’s accurate enough to check the machine tooling and especially the spindle tapers we produce here. In the past, we’d use hard gages and we still use them, but only for certain OD (outside diameter) checks. We’d blue up the tapers, insert them, give them a good twist and do our inspections, but there was way too much inconsistency. Today, with sophisticated HSK tooling, this method is too hit or miss to be reliable. Air gaging provides dead stops on the test stand and the documentation is unbeatable for validation on the straightness, surface finish and taper angles. Plus, the Stotz system allows us to upload all the data on every part, so we have our favorite word—documentation—for every part we produce.” Hobbs also comments on the userfriendliness of the Stotz air column. When the program is first input into the column for a part in the AME grinding department, for example, the Stotz column essentially becomes a programmable logic controller, providing hard data via the Ethernet connections to the host database. In this manner, every parameter of every part is documented and recorded. In a classic example of the law of unintended consequences, this process is not only used on the parts run, it also is used for calibrating the AME machines, in a predictive maintenance function. At AME, various testing of machined spindle interface and other components is performed both at the machines in the grinding department, in a temperature-controlled 72 F environment, plus in the company’s totally environment-controlled inhouse testing department, supervised by the company’s director of quality, Brad Patterson. He confirmed Hobbs’ observation that numerous other technologies have been investigated over the years for quality checking at AME and that air gaging has been found to be the best and most reliable for this company’s applications, particularly inside diameter (ID) dimensions and configuration. Patterson also observes, “The sophistication of the Stotz air column is unmatched in the industry. We get all the data required and we get it in exactly the fashion needed to support our customers. Repeatable results and elimination of error occur every time. Plus, the set-up is much faster than on our laser mics, which can’t be used for ID measurement.” Patterson further notes that the replacement of the bluing technique, one he termed a “black art,” with air gaging has brought and keeps AME up to the most current industry standards for quality evaluation. THE STOTZ AIR COLUMN The typical Stotz air column found here is the Model MSG, with four pneumatic channels or 10 LVDT channels operating simultaneously, pneumatic length measuring, user-specific programming up to 18 programs per column, full statistical analysis and full data transfer capability within the host network. All information is fed into the AME host computer by serial number, so any job can be quickly retrieved, while historical records on any part produced can be easily called up for evaluation, deviation claims or to dovetail with a customer’s internal quality protocols. Typically, as AME’s Grinding Supervisor Sam Schubert explains, the finished product will rest for 24 hours of soaking, allowing the diameters to normalize. Though statistically predictable for most metal materials, thermal expansion can cause off-normal readings to occur. For checking certain bearing journals or spindle shafts, snap gages are set to accommodate size measurements down to the 20 millionths (0. 00002 inch) range. The acceptable diameter tolerances for most AME products measured are in the one- to two-tenths (0.0001-0.0002 inch) range. In cases where new masters are made for setting control values, those values are preset offline and programmed into the air column’s software, according to Hobbs. Stotz typically performs this function for the customer in a remote manner over the Internet, through a proprietary IP address. Among the many products finished in this grinding department are CAT/ ISO 40 taper spindles, HSK test arbors, HSK grind quills and HSK steep taper milling tools. Often, older and worn spindle shafts are reverse engineered by AME for retrofits and remanufacturing. Even in these cases, air gaging is used to evaluate the finish process on the ID taper, as this technology is easily adapted to such applications, according to AME personnel. Schubert expands on the use of Stotz air gaging at AME. “We have a full and very expensive inventory of hard gages with state-ofthe- art indicators attached. But the air gages can do so much more. We use them for set-up on the grinding machines and they save us hours, every week. When you run the number of jobs we do here, that translates into substantial, additional work product and therefore more revenue for the company. In terms of reliability, some of the Stotz air gages we run here have been at AME since we began using the technology, nearly 10 years ago now.” Schubert also notes the air gaging set-ups on the grinders dramatically reduce the time to first part in his department’s operation. On one major spindle shaft project for an Asian machine tool builder, who was looking for a local source of supply in America, Schubert notes, AME was confronted with an unusually large quantity run, where tool degradation during the run would normally impact the production at some point. After an initial batch was produced, the machine builder claimed that everything but the taper was satisfactory. Surprised by this claim, AME checked all the documentation and determined that the customer’s test unit was actually out of spec, in a case where the error was repeated consistently and thus overlooked. In that instance, the AME products were deemed better than perfect. Schubert cites a useful analogy here. “The documentation we can produce from the air gaging procedure is like a birth certificate on every unit we make. All our spindle shafts for customers, for example, can be viewed as a series of genetically identical twins to each other and we’re providing the documentation of their DNA.” As evidence of their commitment to this technology, Schubert notes that AME is now purchasing air gaging fixtures for all new customer applications. This quality spindle interface manufacturer aims to “keep breathing easy” in their process and product validation, as a result. Improving Fuel Efficiency Aerodynamic Trailer Systems Ltd. (ATS, Auburn, OH) has developed a new product that fits on commercial trailer doors to provide a more aerodynamic shape to the rear of the trailer. The objective is to create a green technology product that reduces emissions by improving fuel efficiency of overthe- road trucks. The product, an inflatable boattail, is an aerodynamic device that reduces drag caused by air flowing in a random, turbulent manner around the rear of a commercial trailer. The design effectively changes the flat surface of the rear doors to a curvilinear shape. It is constructed from a heavy-duty flexible polymer material that automatically inflates and deflates by means of a blower and valving system at pre-set highway speeds. In the deflated position, the rear doors can be fully opened for loading freight. “The inflated boattail is a uniquely curved shape that is very difficult to pre-determine on engineering drawings or measure, which makes it difficult to model,” says Jim Domo, ATS chief executive officer. “We wanted to measure the aerodynamic profile of the device. Since a truck trailer is too big to fit in a wind tunnel facility, we needed to create a scaled model that would describe the exact physical shape. In parallel, we needed a digital version of the boattail in order to perform a software-based computational fluid dynamics (CFD) analysis.” DATA MANAGEMENT DELIVERS ATS contacted 3D Scan IT Inc. (Royal Oak, MI), to discuss alternatives to traditional data gathering techniques. 3D Scan IT technicians recommended a noncontact, high-density scanner as a data gathering approach, and brought an Imetric-IScan White Light scanner to the company’s facility. “We first used photogrammetry to set up navigation points on the surface of the boattail, and then we performed a complete scan using the Imetric white light scanning system,” says Bob Squier, 3D Scan IT Inc. president. “The scanning process took about three hours.” The data was acquired using the PolyWorks software suite. A total of 62 scans were taken and registered to the photogrammetry coordinate system. The aligned scans were then processed to create a polygonal mesh that removed all the overlapping scan data while removing the fabric texture and reducing the file size. PRECISION MODEL ATS also wanted to test the boattail performance in a wind tunnel. “The goal was to create a file that we could use in a rapid prototyping process to quickly create a . Scale model of the boattail device that would be used for performance testing in a wind tunnel,” said Patrick Ryan, president of ATS. To perform the simulation, the polygonal model was sent to the Auto Research Center in Indianapolis. This wind tunnel testing facility, designed primarily for testing race cars, is an open jet, rolling road design that accurately replicates highway conditions. To create a scaled model of the boattail, they used a Stratasys FDM 8000 rapid prototyping machine and the watertight polygonal model. “We planned to use that wind tunnel test data to make any lastminute design changes to the device before we went into production, so it Was critical to our program that the model be as accurate as possible,” Ryan says. First, a curve network was created by using the curve extraction and editing functions of IMEdit. Automatic NURBS surface fitting procedures create the surfaces as the curves are completed. The PolyWorks IMInspect module was used to align the model to the global coordinate system of the trailer doors since the boattail had to exactly fit the door area without obstructing the hinges. The optimized NURBS model was sent to specialists from NASA to perform CFD analysis. This analysis provided a quick overview of the aerodynamic performance of the inflatable boattail under various conditions. The NURBS model also was exported to ATS’s SolidWorks software suite to be used for future modifications and production purposes. REDUCING FUEL CONSUMPTION UP TO 5% According to Domo and Ryan, the . Scale model of the boattail created by the laser scanning and point cloud data management process was a dimensionally precise model of the full-size device, virtually an exact replica. “We were confident that when we conducted wind tunnel testing we would get meaningful results that would apply directly to the full-size device,” Ryan says. Test results indicated that the boattail could reduce fuel consumption by up to 5%. “That translates into fewer emissions and reduced fuel costs through the improvements in aerodynamic drag on the trailer,” says Domo. A traditional approach to product design and development would simply not have achieved the results for which the company was looking. Design in Cost Reduction With campuses around the globe, Motorola University (MU, Chicago) has been an educational innovator in business and technology since 1974. Newer campuses in Asia meet a growing need for business optimization programs that produce results in a global marketplace of shifting economies and rising manufacturing costs. Steven Lee, instructor at Motorola’s Quality Institute in Taiwan, trains teams of Motorola employees, customers and supply chain partners to integrate Motorola’s legacy Six Sigma program with lean initiatives and software that facilitates the design for manufacture and assembly. His approach is an applied business strategy that works: This year, a top electronic device manufacturer completed 12 product redesign projects in four months, saving $6.8 million. The quest for faster and better product development strategies leads busy engineers and business managers to Motorola University. “The average product manufacturing lifecycle is very short, about three to six months, and Motorola’s global development teams and customers launch hundreds of new products each year,” says Lee. “So we are always under pressure to improve, to retain quality with a current heightened emphasis on cost.” This focus on speeding a highquality, yet inexpensive product to the consumer includes using Design for Manufacture and Assembly (DFMA) software from Boothroyd Dewhurst Inc. (Wakefield, RI). DFMA INTEGRATION DFMA software is based on two interlocking approaches: Design for Assembly (DFA) and Design for Manufacturing (DFM). DFA guides engineers to evaluate the functional purpose of each assembly component in a conceptual design, helping them to simplify the design and reduce parts. DFM identifies and calculates the costs associated with manufacturing and finishing parts in alternative processes. A clear goal of a DFA project is part reduction, as part-count reduction is the mechanism for eliminating labor content. While no design tool removes labor content from a product, reduced labor content is the result of partcount reduction. “Our primary mission at MU is to provide learning solutions to internal and external customers to enhance overall business performance,” says Lee. “Six Sigma can enhance product quality, cost, delivery, service and customer satisfaction, and the DFMA program is key to optimal design and reducing manufacturing costs.” Motorola University emphasizes collaboration and integration, with cross engineering between design and industrial engineers, and even interorganizational teams of engineers and business managers. “We also encourage customers to build their annual business balance scorecard according to customer cost strategies and key performance indexes that integrate Six Sigma and DFA methodology,” says Lee. Each company is required to keep a scorecard that blends all these sciences and helps quantify project goals and results. Students find DFA user friendly, and are impressed by the significant reductions in part count and assembly time. “Overall average part-count reduction is 35% for new product design and 11% for existing product redesign,” says Lee. “We find that introducing DFA at the initial design stage generally gives the most cost benefits.” Ultimately, a direct engagement of business leaders, and training in DFMA, promotes support from top management in customer organizations. When the value of engineering tools such as DFMA is made clear to management and to Motorola customers, “DFMA becomes institutionalized as part of a greater business strategy,” says Lee. This approach reinforces success. “Then these people return to their companies, taking with them lean, Six Sigma and DFMA real-world experience— carrying this message with them.” DFMA LAPTOP DESIGN A top Asian electronic device manufacturer (EDM) wanted to reduce the manufacturing cost of their laptop by at least 30% within six months. The company had been using Six Sigma for several years, but was “looking for a systematic methodology to improve overall performance,” says Lee. With this In mind, Lee trained a team of the company’s employees to reduce the part count and assembly time of the laptop with DFMA. Part-count reduction as a means to reduce labor content is fast becoming a cost reduction strategy to offset rising labor costs in Asia. “Each year labor costs in China increase by 10%, driving either cost reduction or shifting labor to Vietnam or back to home countries,” says Lee. The EDM training class had more than 100 participants, from backgrounds that included design engineering, manufacturing and product management, with professional experience ranging from two to 20 years. Some had Six Sigma Black Belts and others were assigned Green Belts. To stay on track, Lee had just one day to train his class in DFA software, and two days for project coaching. Along with the Six Sigma statistical method, and the lean approach to cutting waste, Lee taught the EDM team to integrate DFMA—for design iteration, benchmarking and overall cost reduction. The cost information stored in the program reduces time-consuming recalculating that engineers would otherwise need to do. “To improve manufacturing time, we simply consult the program instead of standing on a factory floor with a stopwatch doing time studies, which have become obsolete,” notes Lee. The Motorola/EDM team reduced their laptop parts by 36% in 90 days using the DFA Project Quick Win model. They also were trained in DFMA practices. In total they completed 12 projects, saving 30% on part count and assembly time for a PDA, 41. 3% part count reduction on an LCD TV and 57.5% reduced part count on a server. For the laptop, DFA identified fasteners and clamps for elimination, parts for consolidation and improved ease and time of assembly. Laptop design engineers brought their original design to the table, and in collaboration with Motorola instructors the laptop design was refined and improved dramatically using a smooth and focused collaborative process. Lee notes that DFA as a “systematic and objective methodology clearly promotes the evolution of design iterations and overcomes any hypothetical resistance against innovation.” Lee believes that the University’s Six Sigma, lean and DFMA project model, through sponsorship from business unit heads, business scorecards and presentations of final product design, fully engages business management in the product design process, producing lasting effects. In other organizations, engineering is largely separated from business management, but the Motorola approach bridges that divide and brings business leaders right to the CAD table. “To realize maximum cost efficiency in the long term it is imperative to foster a shared perspective between management and engineering,” says Lee.
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