To maintain and improve its competitive position in the marketplace, Millennium Industries -- an Auburn Hills, MI-based automotive fuel rail manifold manufacturing company -- recently challenged itself to further improve manufacturing processes as well as reduce both capital equipment and operating costs. This task involved modifying its leak testing process to provide faster and more cost-effective feedback as to the quality of the brazing operation, a form of soldering that utilizes high temperature alloys to join high temperature metals.

The Situation

Traditionally, fuel rail manifolds are tested using either pressure decay or helium mass spectrometer technology. However, Millennium Industries wanted to move the testing closer to the critical brazing process to receive immediate feedback that would not only identify the presence of a leak but also pinpoint its actual location, an even more critical aspect of leak detection that significantly improves manufacturing efficiency. This immediate feedback would reduce scrap as well as permit the company to accurately and efficiently monitor and correct the fluxing and brazing process. To accomplish this task, the company needed a more accurate and effective leak test system -- a system that would not be affected by temperature and that would also require less maintenance than the existing system.

The fuel rail manifold distributes gasoline from the gas tank via fuel lines to fuel injectors mounted to each cylinder of the automobile engine. The fuel rail manifold construction consists of three to four injector cups, fuel regulator mount, and fuel line tubes, which all need to be brazed to a sealed tube. The leak-tight integrity is critical for safety, engine performance, and environmental protection. Leaking gasoline on a hot engine is detrimental to safety and also increases vehicle operating costs while adversely affecting engine performance. The emission of hydrocarbon vapor (fuel vapor) is an environmental concern.

The Solution

Cincinnati Test Systems, Inc, which had previously supplied the fuel rail company with pressure decay and mass spectrometer systems, introduced the Falcon Leak Test System® as a cost-effective solution to the customer's challenging quality improvement initiative. The Falcon Leak Test System is a helium-based system with chambers, designed for each fuel rail manifold, that incorporate strategically placed Intelense helium sensors. The Falcon System® monitors the Intelense sensors -- which respond immediately to a helium leak -- to accurately determine the leak location and accumulate the total leak rate for the manifold under test. An immediate response is provided that is both accurate and consistent because the Falcon Leak Test System® functions independently of the fuel rail manifold's temperature as well as any small changes in pressure due to temperature variations within each manifold being tested. This system significantly improves upon the function of other pressure decay systems.

Temperature neutrality allowed the Falcon System® to be integrated into the manufacturing process immediately after the brazing furnace, when parts are more than 120º F and rapidly cooling. After each test, a graphic depiction of the fuel rail manifold appears on the operator screen. If a leak is detected, its specific location is indicated on the onscreen view of the fuel rail manifold, along with the total leak rate. The leak location and leak rate information are immediately communicated, alerting operators to take corrective action to ensure that proper adjustments are made quickly to the fluxing operation.

Timely feedback was pertinent in the success of reducing scrap and improving production efficiency at Millennium Industries. Overall long-term maintenance on the system was greatly reduced vs the mass spectrometer vacuum system because the Falcon Leak Test System® does not have a vacuum chamber, a chamber vacuum pump, a mass spectrometer instrument, or a backing pump for the mass spectrometer.

Conclusion

Automotive supplier Millennium Industries successfully met its objective to improve manufacturing process efficiency, improve quality, and reduce costs. With more effective, easier-to-maintain leak test equipment, it received faster leak test results due to the ability of the Falcon System® to operate effectively, even in close proximity to the brazing operation. Immediate feedback indicating the leak rate as well as the specific leak location allowed the supplier to make timely corrections to the manufacturing process, reducing the scrap rate. The company also saved floor space and reduced capital equipment by eliminating an offline repair test station. The Falcon Leak Test System® helped Millennium Industries reduce its overall costs, improve product quality, and enhance its competitive market position.