ASSEMBLY JANUARY 2015 www.assemblymag.com Testing Transmissions pg 62 Medical Assembly 34 Dispensing Grease 40 Automated Riveting 46 Postponement Strategy 52 Welding Aluminum 56 *BONUS FEATURES* WIRE PROCESSING SPECIAL SECTION after pg 44
34 January 2015 Vol. 58, No. 1 ASSEMBLY 66 COVER STORY 62 Leak Testing Aluminum Castings Helium-based leak detectors can quickly find even microscopic leaks in cast aluminum components. Steve Kurzava FEATURES 34 How to Respond to FDA Form 483 Manufacturers must react promptly or they risk getting a Warning Letter. 40 Lubricant Dispensing Accurately placing just-enough oil or grease onto a part is easy with the right dispensing system. Jim Camillo 46 Automating the Riveting Process Plenty of options are available for semi- or fully automatic riveting. Jim Camillo 52 Postponement Helps Sensor Maker Thrive To reduce its inventory costs, Dynisco needed to change how it designed and assembled its products. Miles Parker 56 Aluminum Welding Made Easier New technologies are making MIG welders a good option for joining aluminum. Mike Vandenberg 66 Drawers vs. Shelving Flexible drawer storage cabinets can save time and floor space. John Alfieri 40 62 DEPARTMENTS Editorial...6 Are you ready for Industry 4.0? John Sprovieri New & Noteworthy... 8 Cordless pulse tools features brushless motor. Automotive Assembly...10 The future looks bright for smart headlights. Assembly Lines...12 Assembly Plant of the Year award call for nominations. Assembly in Action...22 Welding cell a productivity boom for Liebherr. Jim Camillo Assembly Products...72 Adhesives, grippers and other assembly products. Classified...86 Advertisers Index...87 On Campus...88 UC San Diego lab delves into wearable electronics. NEXT MONTH Delta Robots Laser Welding of Plastics Automatic Screwdriving Pneumatic vs. Electric Actuators Cover photo courtesy Ford Motor Co. 2 ASSEMBLY / January 2015 www.assemblymag.com
ASSEMBLY Leak Testing Leak Testing Aluminum Castings Helium-based leak detectors can quickly find even microscopic leaks in cast aluminum components. In the outside-in test method, a vacuum is pulled on the part and the test chamber is filled with a mixture of air and helium. If there s a leak, helium will migrate into the part, where it will be detected by the test instrument. Photo courtesy KUKA Assembly and Test Corp. For information on how to obtain reprints/e-prints of this article, please contact Cindy Williams at williamsc@bnpmedia.com or 610-436-4220 ext. 8516. By Steve Kurzava Technical Specialist KUKA Assembly and Test Corp. Saginaw, MI Next to the engine, the automatic transmission may be the most important subsystem of an automobile. It plays a key role in handling, performance and fuel economy. Since automatic transmissions rely on fluid couplings to transmit rotating mechanical power, it s vital that they don t leak. Detecting component leaks at the earliest stages of manufacturing after casting and before assembly saves transmission manufacturers significant expense and headaches. KUKA Assembly and Test Corp. is a systems integrator specializing in assembly and test systems for major automotive subsystems, such as engines, transmissions, axles, suspension components and steering components. Our customers include Ford Motor Co., Borg Warner Inc., Harley-Davidson Inc. and Caterpillar Inc. We use helium leak detectors to assist in the production of advanced automatic transmissions, such as the new nine- and 10- speed transmissions developed to help improve fuel economy. Historically, many leaks are discovered at or after final assembly. Our fixtures and jigs are equipped with helium leak detectors from Inficon. This enables us to detect most leaks soon after the parts are cast, reducing cost by eliminating defective castings early in the assembly process. Testing Trannies KUKA s leak-test processes use partspecific fixtures and automation. After casting and machining, transmission housings are robotically loaded into the test chamber. Inside the chamber, the worm trail and other cavities are sealed with a part-specific fixture machined to tight dimensional tolerances. Once the part has been clamped and sealed, the chamber is evacuated. Helium is then injected into the enclosure, which is connected to an Inficon LDS3000 helium leak detector. Fans agitate the air inside the enclosure to create a uniform mixture of 1 percent helium and air. The leak detector is connected to the test part through a valve and tooling on the worm trail. When the valve is opened, helium surrounding the exterior of the part can migrate into the interior of the part through porosity leaks, cracks, thread leaks and other pathways. It will move through the housing and into the transmission, where it will be detected and quantified by the leak detector. At that point, a pass-fail decision based on standardized leak rates can be made, and data can be collected for traceability. All passages are individually tested. The Inficon helium leak detector is more accurate than air or underwater testing for detecting porosity leaks, notes Thomas Parker, Inficon s automotive sales manager for North America. For example, an area just 1 inch in diameter on an aluminum casting might have up to a trillion holes that helium molecules can migrate through. Porosity of this kind would never be detected by air or underwater testing. Leaks don t necessarily look like cracks or perfect circular holes. They may resemble a cave-like system of microscopic cracks and pockets within the metal. With air pressure testing, the required time to detect a pressure 62 ASSEMBLY / January 2015 www.assemblymag.com
Leak Testing in the chamber and sealed. drop (which is needed to rates The transmission and test measure the low leak chamber are then evacuated now required by automakers) might be days. simultaneously, and the transhelium leak detection takes mission is backfilled with seconds, with a total part-tohelium. Because the pressure part test time of roughly 30 to differential on the transmis40 seconds. This short interval sion seals cannot exceed 4 makes leak detection as timely psi, the transmission is interas any production process. nally pressurized with 100 A standard industry-perpercent helium at approximissible leak rate is approximately 3 psi. mately 1 standard cubic cenif a leak is present, helium timeter per minute (sccm). As will migrate out of the transtransmissions have become mission housing and into the more complex, so, too, have test chamber, where it will Detecting component leaks at the earliest stages of manufacturing the fluids inside them. Per- after casting and before assembly saves transmission manufacturers be detected by the Inficon formance requirements are significant expense. Photo courtesy KUKA Assembly and Test Corp. LDS3000 instrument. higher, and leak rates are The inside-out test is perlower. For instance, newer nine-speed again, this time from the inside-out. formed because manufacturers preand 10-speed transmissions may have Instead of pulling a vacuum on the part fer to test within the design criteria leak rate requirements of 0.1 sccm or and filling the test chamber with helium, of the item being tested. For an autolower. the procedure is reversed. A vacuum matic transmission, fluid pressures are is pulled in the test chamber, and the exerted from interior to exterior. The Final Check transmission is filled with helium. inside-out test with helium replicates Near the end of the assembly line, The process works like this: The those operational conditions. If, under transmissions are often leak-tested fully assembled transmission is placed pressure, passageways are squeezed or 64 ASSEMBLY / January 2015 www.assemblymag.com
improves safety. Because of the joints expanded, helium can sensitivity of Inficon helium escape in the same manner leak detectors, only a small fluids might leak. Despite the amount of helium is required complexity of a transmission to test a part. Depending on the with its solenoid valves, torque part, a typical helium test costs converters, worm trails and other pathways helium can approximately $0.09 per part. pass rapidly into the vacuum if Even at low pressures, helium there are leaks. can reveal time-based leaks, The helium process is such as stringers and porosity, a more repeatable test when which might be missed with compared to other test methmass-flow and pressure-decay ods, and it s not temperaturetests. dependent, explains Parker. The worm trail and other cavities are sealed with a part-specific If you have a porosity Helium leak detection takes fixture machined to tight dimensional tolerances. Photo courtesy condition in which there are a KUKA Assembly and Test Corp. many variables out of the test trillion tiny holes, tracer gas is equation, achieving high gauge repeat- pressure decay, are influenced by part the only method that can find the leak, ability and reproducibility. volume. Larger volumes equal longer says Parker. You may miss a leak with Compared with air-testing methods, test times and reduced sensitivity. pressure-decay or mass-flow testing, helium testing offers several advantages. Pressure-decay testing requires because they are not going to find For one, air testing is significantly stabilization time. In some cases, the millions of near-molecular sized leaks. affected by temperature. Hot parts or pressure in the part might need to be Defects are often at the gusset points of cooling parts can cause a mass-flow topped off multiple times. However, a casting. The casting process causes test to be inaccurate and unrepeatable. adding pressure also adds heat, which inclusions in the aluminum, which Second, tracer-gas leak tests are not can affect the accuracy of the test. creates a leak pathway. Weight-saving Helium leak detection takes place thin walls also can create potential dependent on the volume of the part. Air test methods, such as mass flow and at lower pressures. That saves time and porosity problems. Visit ASG at the Booth 3118 February 24-26, 2015 San Diego Convention Center San Diego, CA Products and Solutions for Assembly ASG, Division of Jergens, Inc. 888.486.6163 216.481.4519 www.asg-jergens.com www.assemblymag.com January 2015 / ASSE M B LY 65