1 . Define how the definition of reliability presented in the attached applies to the performance tests described. Do these tests measure inherent reliability or achieved reliability?

2. For the examples of product testing provided in the attached case, discuss what quality/reliability measurements might be taken and how the data might be analyzed. For example, are the measurements attributes or variables? Would they be analyzed using descriptive statistics, Pareto charts, etc.?

QUALITY in PRACTICE testing Audio Components at Shure, Inc. ure Incorporated is a global, privately held com- headquartered in Evanston, Illinois, with . Mobile Communications: Audio subsystems, such any anufacturing facilities in illinois, Texas, and Mexico, as hands-free cellular, within the automotive envi- nd sales offices in s in Germany and Hong Kong ronment. Microphones need to perform in a vari- ure's mission is to deliver high-performing, quality. ety of temperatures. aged and reliable audio products, and to provide 5. N. Shure began the company by launching a perior customer service and support. Shure's phi- one-man operation in 1925 that sold radio parts kits. sophy is to be market-driven iven and customer-focused It was the microphone that marked the company's their chosen markets. Each market segment has its entry into manufacturing in 1932, and the micro- wn quality and reliability needs: phone remains Shure's flagship product to this day. Because of its emphasis on engineering research, Performance Audio: Musical performers and Shure products became known early on for their out- those who record and monitor their work on standing quality and durability. During World War II, stage or in the studio. Anyone who has attended Shure was awarded a U.S. government contract to a rock concert can attest to the rough treatment provide microphones to the military, and needed to microphones receive from the entertainers, some meet strict specifications for performance and rugged- actually throwing them across the stage. ness. Shure took the extra step to develop a rigorous Presentation and Installation Audio: Anywhere a in-house testing program that remains in place today. sound system is installed, such as houses of wor- In addition to microphones (both wired and wire- ship, hotels, conference rooms, clubs, theaters, less) and phonograph cartridges, Shure manufactures and auditoriums. Many users are unfamiliar with a number of other audio electronics products, include the acoustical characteristics of the equipment ing mixers, digital signal processors, personal monitor- they are using and sound technicians are often ing systems, and digital feedback reducers. Shure's not on site, so the equipment really needs to quality philosophy is reliability oriented. Products are run by itself. tested for reliability well beyond the warranty period, * Radio and TV: Broadcast industry both in studio and with the goal of providing the customer long-term on location in the field. Technicians need to have service and satisfaction. Testing is designed to simu- total confidence in the equipment they are using late actual operating conditions. Shure has more than on a live, remote broadcast, because they cannot 80 test procedures in place. The following are a few go back and redo that on-the-spotinterview. examples: Consumer Market: Phonograph cartridges and . Microphone Drop Test: To determine whether a low-cost microphones, including audiophiles, microphone is capable of dynamic shock stress. hip-hop DJ's, and home recording. Scratch DJs lit- Initial performance data are taken on the mic. Braly take a record and pull it back and forth to Then the mic is dropped numerous times onto a the beat of a song, causing tremendous pressure hardwood floor from a height of 6 feet at random on the phonograph stylus. angles. The mic is "talked out" after every twoPART 2 Tools and Techniques for Quality drops. After the drop tests, level and response are impacts. A cartridge mounted in a tone arm is tested and compared to the initial data. Any unit dropped onto a moving record at least 100 times not meeting original print specifications is consid The cartridge is scraped across a moving record 100 times. This test simulates and exceeds any abuse ered a failure. Perspiration Test: To evaluate the corrosion resis- given to the cartridge and stylus in normal use. tance of painted/plated parts exposed to an acid Temperature Storage: To determine ability to solution simulating sweat. Parts are placed in a withstand extreme temperatures for extended perspiration chamber that consists of a stand sup- periods of time. Initial performance data are porting the parts over a large glass jar containing taken. For high temperature, the product is acid solution. Parts are inspected daily for placed in a preheated high temperature chamber amounts of corrosion for a period of seven days. for seven days. The product is allowed to stabilize Parts are then compared to good control parts to at room temperature for 24 hours and then the determine amount of corrosion present. same performance data are taken. For low tem Cable and Cable Assembly Flex: To ensure that any perature, the product is placed in a low tempera cable that would normally be subjected to random ture chamber for seven days, allowed to stabilize twisting motion under tension will meet field require- to room temperature for 24 hours, and tested. ments. Cable flex test equipment provides for two independent motions: rocking motion and rotation, By performing these and other rigorous tests, Shure and twisting motion and rotation. Cables not meet- consistently meets its goal of exceeding customers ing flex life specification are considered a failure. product performance and reliability expectations. Sequential Shipping: To evaluate the packaging effectiveness and mechanical integrity of the prod- Key Issues for Discussion uct under simulated shipping conditions. This test 1. Describe how the definition of reliability pre- is used for all Shure products. Products packaged sented in this chapter applies to the performance for shipping are given the following tests, in order: tests described here. Do these tests measure drop test, vibration test, and rough handling test. inherent reliability or achieved reliability? When the product is removed from its packaging, 2. For the examples of product testing provided in it must appear and operate as new. If appropriate, this case, discuss what quality/reliability mea an electrical test is performed and compared to initial electrical test data. surements might be taken and how the data might be analyzed. For example, are the measure Cartridge Drop and Scrape Test: To determine abil- ity of stylus to withstand accidental drops and side ments attributes or variables? Would they be analyzed using descriptive statistics, Pareto charts and so on