Leak Path Testing and Industrial CT Scanning

Industrial CT scanning services and a little ingenuity are used to solve leak path testing failures. Going above and beyond to get the customer inside a sealed bottle to find defects.

Leak Path Testing:

For medical device manufacturers, leak path testing can help attenuate risk, product failure, or problems in the assembly process. What happens when the test fails, but the leak path cannot be identified? A major medical device company comes to us with a bottle that holds sterile water used for irrigation in medical procedures. The leak path testing they conduct in their factory involves placing the bottle under vacuum pressure to detect inside-out leaks. Their leak tests are failing their maximum allowable leakage for proper functioning and safety. Nel PreTech uses industrial CT scanning on the known leaky bottles after they go through vacuum testing, but the leak path does not show after restoration of atmosphere. The evidence of leaking appears once pressure is released, but ct scanning once the bottle is returned to standard temperature pressure (STP) does not produce the necessary data to find the real source of the defect.

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Industrial CT Scanning Products Under Vacuum Pressure:

In this example, it is necessary to apply industrial ct scanning techniques on the bottle while it is still under pressure to determine what is different while the bottle is squeezed. Since the customer can’t see inside the product while they are conducting their leak path testing, we present a solution. At the Nel PreTech laboratory, our engineers surpass what our competitors are willing to take on. By combining our resources, expertise, and problem-solving skills we can work to find the customer a solution for their analysis needs. There is no single method that can fit every criterion. Each ct scan involves different techniques. In this case, Nel PreTech engineers design experiments, procure material, and validate through testing. The idea is to observe evacuation of liquid while under pressure over a pre-determined amount of time. A vacuum chamber is placed inside the industrial ct scanning machine as the entire unit with bottle enclosed is scanned using x-rays. The x-ray beam passes through the vacuum chamber and bottle leaving an image on a detector screen. This detector translates the x-rays into visible light, producing the image of the bottle while it remains under pressure.

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Filters and Contrast:

The less filter you have the better the contrast you’ll have in a computed tomography image. Some plastics and water are very close together in density, as in the case of the bottle of sterile water. It is hard to tell the materials apart when an industrial ct scan is performed. If you lower the contrast, you won’t see a difference between the plastic and water. A lot of pressure vessels used in leak path testing are made of steel, which is an extremely dense material. Fortunately, we have a vacuum chamber made of aluminum with thin walls. This essentially acts as a pre-filter and allows us to preserve contrast much better during the ct scanning process. For the customer, this procures the imagery needed to determine the flaws in the material or assembly that are causing the leaks.

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Sometimes at Nel PreTech, we take on unique projects that require a unique perspective and abilities. We welcome it and aim to exceed expectations to present the exact scans and support the customer needs.

If you have assemblies or products that need this level of inspection, contact us today!