*BONUS FEATURES*WIRE PROCESSING SPECIAL SECTION after pg 44

Testing Transmissions

pg 62

Medical Assembly 34

Dispensing Grease 40

Automated Riveting 46

Postponement Strategy 52

Welding Aluminum 56

ASSEMBLYJANUARY 2015 www.assemblymag.com

Editorial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Are you ready for Industry 4.0?—John Sprovieri

New & Noteworthy . . . . . . . . . . . . . . . . . . . 8Cordless pulse tools features brushless motor.—Austin Weber

Automotive Assembly . . . . . . . . . . . . . . . 10The future looks bright for smart headlights.—Austin Weber

Assembly Lines . . . . . . . . . . . . . . . . . . . . . 12‘Assembly Plant of the Year’ award call for nominations.—Austin Weber

Assembly in Action . . . . . . . . . . . . . . . . . . 22Welding cell a productivity boom for Liebherr.—Jim Camillo

Assembly Products . . . . . . . . . . . . . . . . . . 72Adhesives, grippers and other assembly products.

Classified . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Advertisers Index . . . . . . . . . . . . . . . . . . . . 87

On Campus . . . . . . . . . . . . . . . . . . . . . . . . . 88UC San Diego lab delves into wearable electronics.—Austin Weber

Leak Testing Aluminum CastingsHelium-based leak detectors can quickly find even microscopic leaks in cast aluminum components.—Steve Kurzava

How to Respond to FDA Form 483Manufacturers must react promptly or they risk getting a Warning Letter.—Austin Weber

Lubricant DispensingAccurately placing just-enough oil or grease onto a part is easy with the right dispensing system.—Jim Camillo

Automating the Riveting ProcessPlenty of options are available for semi- or fully automatic riveting.—Jim Camillo

Postponement Helps Sensor Maker ThriveTo reduce its inventory costs, Dynisco needed to change how it designed and assembled its products.—Miles Parker

Aluminum Welding Made EasierNew technologies are making MIG welders a good option for joining aluminum.—Mike Vandenberg

Drawers vs. ShelvingFlexible drawer storage cabinets can save time and floor space.—John Alfieri

COVER STORY

FEATURES DEPARTMENTS

34

40

62

66ASSEMBLYJanuary 2015 Vol . 58, No . 1

2 ASSEMBLY / January 2015 www.assemblymag.com

40

52

56

66

34

46

62

Cover photo courtesy Ford Motor Co.

Delta Robots

Laser Welding of Plastics

Automatic Screwdriving

Pneumatic vs . Electric Actuators

NEXT MONTH

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. Detect-ing component leaks at the earliest stages of manufactur-ing—after casting and before assembly—saves transmis-sion manufacturers signifi-cant expense and headaches.

KUKA Assembly and Test Corp. is a systems integrator specializing in assembly and test systems for major auto-motive subsystems, such as engines, transmissions, axles,

suspension components and steering components. Our customers include Ford Motor Co., Borg Warner Inc., Har-ley-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 TranniesKUKA’s leak-test processes use part-

specific 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

Leak Testing Aluminum Castings

ASSEMBLY Leak Testing

Helium-based leak detectors can quickly find even microscopic leaks in cast aluminum components.

By Steve KurzavaTechnical SpecialistKUKA Assembly and Test Corp.Saginaw, MI

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.

62 ASSEMBLY / January 2015 www.assemblymag.com

drop (which is needed to measure the low leak rates now required by automakers) might be days.”

Helium leak detection takes seconds, with a total part-to-part test time of roughly 30 to 40 seconds. This short interval makes leak detection as timely as any production process.

A standard industry-per-missible leak rate is approxi-mately 1 standard cubic cen-timeter per minute (sccm). As transmissions have become more complex, so, too, have the fluids inside them. Per-formance requirements are higher, and leak rates are lower. For instance, newer nine-speed and 10-speed transmissions may have leak rate requirements of 0.1 sccm or lower.

Final CheckNear the end of the assembly line,

transmissions are often leak-tested

again, this time from the inside-out. Instead of pulling a vacuum on the part and filling the test chamber with helium, the procedure is reversed. A vacuum is pulled in the test chamber, and the transmission is filled with helium.

The process works like this: The fully assembled transmission is placed

in the chamber and sealed. The transmission and test chamber are then evacuated simultaneously, and the trans-mission is backfilled with helium. Because the pressure differential on the transmis-sion seals cannot exceed 4 psi, the transmission is inter-nally pressurized with 100 percent helium at approxi-mately 3 psi.

If a leak is present, helium will migrate out of the trans-mission housing and into the test chamber, where it will be detected by the Inficon LDS3000 instrument.

The inside-out test is per-formed because manufacturers pre-fer to test within the design criteria of the item being tested. For an auto-matic transmission, fluid pressures are exerted from interior to exterior. The inside-out test with helium replicates those operational conditions. If, under pressure, passageways are squeezed or

Detecting component leaks at the earliest stages of manufacturing—after casting and before assembly—saves transmission manufacturers significant expense. Photo courtesy KUKA Assembly and Test Corp.

Leak Testing

64 ASSEMBLY / January 2015 www.assemblymag.com

joints expanded, helium can escape in the same manner fluids might leak. Despite the complexity of a transmission—with its solenoid valves, torque converters, worm trails and other pathways—helium can pass rapidly into the vacuum if there are leaks.

“The helium process is a more repeatable test when compared to other test meth-ods, and it’s not temperature-dependent,” explains Parker. “Helium leak detection takes many variables out of the test equation, achieving high gauge repeat-ability and reproducibility.”

Compared with air-testing methods, helium testing offers several advantages. For one, air testing is significantly affected by temperature. Hot parts or cooling parts can cause a mass-flow test to be inaccurate and unrepeatable. Second, tracer-gas leak tests are not dependent on the volume of the part. Air test methods, such as mass flow and

pressure decay, are influenced by part volume. Larger volumes equal longer test times and reduced sensitivity.

Pressure-decay testing requires stabilization time. In some cases, the pressure in the part might need to be “topped off” multiple times. However, adding pressure also adds heat, which can affect the accuracy of the test.

Helium leak detection takes place at lower pressures. That saves time and

improves safety. Because of the sensitivity of Inficon helium leak detectors, only a small amount of helium is required to test a part. Depending on the part, a typical helium test costs approximately $0.09 per part. Even at low pressures, helium can reveal time-based leaks, such as stringers and porosity, which might be missed with mass-flow and pressure-decay tests.

“If you have a porosity condition in which there are a trillion tiny holes, tracer gas is

the only method that can find the leak,” says Parker. “You may miss a leak with pressure-decay or mass-flow testing, because they are not going to find…millions of near-molecular sized leaks. Defects are often at the gusset points of a casting. The casting process causes inclusions in the aluminum, which creates a leak pathway. Weight-saving thin walls also can create potential porosity problems.”

The “worm trail” and other cavities are sealed with a part-specific fixture machined to tight dimensional tolerances. Photo courtesy KUKA Assembly and Test Corp.

ASG, Division of Jergens, Inc. 888.486.6163 | 216.481.4519

www.asg-jergens.com

Products and Solutions for Assembly

Visit ASG at the February 24-26, 2015 | San Diego Convention Center | San Diego, CA

Booth 3118

www.assemblymag.com January 2015 / ASSEMBLY 65