November 23, 2022

Sound Scanner makes machine noise visible – Metrology and Quality News

Seven Bel’s patented innovation of a moving sensor Sound Scanners is capable of simulating up to 480 microphone positions over a circular area while using only five built-in microphones. Comparable acoustic cameras are normally equipped with around 100 microphones. This advantage has a significant impact on the quality of the measurement. The unique mobility and handling and the high-quality measurement results make the Seven Bel Sound Scanner P132 a powerful measurement device that can be used and transported easily.

The latest version of the Seven Bel mobile application offers numerous optimizations of existing functions. Acoustic images and audio data can now be analyzed side by side on a large screen. Tablet users can enjoy a higher level of convenience by manipulating the time and frequency domain while immediately inspecting the effect on the acoustic image. The acoustic image and audio data section can be resized dynamically, increasing productivity and usability, leaving more time for problem solving.

Seven Bel’s Acoustic Camera enables machine builders to locate disturbing noises during development and on existing equipment, making it easier to implement targeted measures to sustainably reduce noise levels.

An example of sound application

Machines that work with aluminum are in a world apart. Their acoustics in particular. For example, when the extrusions are made of aluminum, the cavities in the extrusions sometimes increase vibration in a very unique way. The sounds generated are clearly audible, but it is often very difficult to find their exact source.

Matthias Gamisch, Sales Manager of the Upper Austrian special machine manufacturer Fill, gave his opinion on such a case: During the acceptance test, the machine, which was designed for a well-known Austrian customer, made a noise that no one has been able to identify. Quiet but clearly noticeable. However, due to the spatial conditions of the factory, this particular customer wanted maximum noise reduction.

“In such cases,” explains Gamisch, “there is actually a standard solution: the whole machine is enclosed in sound insulation and the job is done”. However, insulation requires space, which can be a problem in production halls where space is limited. However, for the machine delivered by Fill, there was another reason why insulation was not an option: one of the most important features of the machine is a window that provides a view inside, which was specially requested by the customer. If an insulating coating had been used, the window should have been covered.

“In cases where this coating is not an option, there is of course a solution. However, it is more expensive: you build components based on more or less justified suspicions, check if they can cause the noise, reinstall them, check the next one until you find the fault. Or not. You can also try to assess the machine with a microphone, record the noise, and hope the problem is where the noise is loudest. “Unfortunately, this only works to a very limited extent”, explains Gamisch. “Because sound is very easily deflected and rarely penetrates outward from where it is produced directly.”

The camera solution

Fortunately, says Gamisch, when the sound problem arose, he also knew of a third, relatively new option: using an acoustic camera. “We had occasional contact with Seven Bel beforehand. It was time to try out the sound scanner produced by Seven Bel in a real situation.

The result, Gamisch recalls, has repeatedly come as a surprise. Four different sound sources were identified in one afternoon. Above all: “Two of them we might have found without the camera, they made sense in the end. But the other two, I don’t think even our most experienced technicians thought of.

Either way, the time saved was significant. After about a week, during which unwanted noise was suppressed by improved construction, the Seven Bel Acoustic Camera was reused and it was documented, also for the customer, that everything was now green, and the problem arose. was deemed resolved after less than two weeks.

Using conventional methods, Gamisch says, it could have taken five times as long. “So I imagine that acoustic cameras are already used as a test tool for special orders that require particularly quiet machines when building the machine.”

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