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Non-Pressurized Cabin Testing

This blog will explore the use of acoustic ultrasound to perform quality control inspections and end user maintenance on non-pressurized cabins in the aviation, automotive, and heavy equipment industries. Vehicles as varied as F-35 Joint Strike Fighters, compactors, railcars, and 4-door sedans can all be tested using a similar procedure.

Automotive / Heavy Equipment Cabin Testing

Most automotive manufacturers use some variation of “rain” or watershed testing to verify the integrity of gaskets and seals around windshields, doors, and passenger windows of their vehicles. Current methods used by most manufacturers are unnecessarily cumbersome and time-consuming.

Once a vehicle has progressed far enough through the assembly process for all glass fixtures and doors to be completely sealed, the cabin of the vehicle is tested for leaks in the gaskets around windshields, door frames, and door windows. This is typically accomplished with a watershed test station. A member of the manufacturing team is seated inside the vehicle, as the chassis is processed through the rain test stand.

Automotive / Heavy Equipment Cabin Testing

The watershed is turned on for 8-12 minutes, and the person inside the vehicle visually inspects all seals for signs of leakage. If a leak is located, it will be marked for repair. In some instances, immediate clean-up of the water is required after the vehicle is removed from the watershed in order to comply with safety regulations.

If no leaks are located, the vehicle is returned to a previous station for repair and must be tested again. The likelihood of a failed test varies between manufacturers and depending on the vehicle being tested, but it can be as high as 12%. The average in the automotive industry is approximately 1.2%, while the average for heavy equipment manufacture is approximately 3%. In all, the process requires at least two members of the manufacturing team to execute each inspection and consumes around 10-15 minutes of time per vehicle. Depending on the volume of the plant and the size of the vehicles it produces, the square footage of the assembly area dedicated to watershed testing can range from 500 to 5,000 square feet.

Ultrasonic cab testing is faster and safer than watershed testing. The UT200 ultrasonic transmitter is turned on and placed inside the cab on the dashboard. In larger vehicles, a second transmitter is placed in the rear of the cabin, as well. All doors are closed. The UL101 ultrasound receiver is turned on and utilized by the tester to scan all window gaskets, welds, and door seals. The entire procedure on a heavy equipment cab takes about two minutes. On an automobile, SUV, or truck, the procedure takes approximately five minutes. If there is no leak, the vehicle is moved on to the next station. If there is a leak, the vehicle is moved to a previous station for repair

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