AQCURA | Acoustic Quality Control Testing

AQCURA can help to increase the number of samples tested and reduce the chance of failing products to be delivered to customers. Particle velocity sensor enables to perform EOL QC directly in the production line. This saves time and money but moreover due to fast test cycles it could increase the ratio of tested versus total produced products. E.g. instead of testing just 1 out 5 products test all of them. Reducing the change of a faulty product leaving your factory to the minimum.

Typically, the products under test are more complex comprising more (sub) components. The cos price per module is too high to simply discard bad tested products. Besides, objectively define good or bad a deeper level of insight is required. The state of the AI and ML algorithm will identify multiple complex vibro-acoustic problems that could lead to different reasons for failure. Using multiple advanced features helps to lead to the root cause. This information will help to fix the majority of the bad tested products and get them to pass in the second round.

AQCURA excels in flexibility; it can be used in combination with any sensor or testing routine and is easily scalable. This allows to control multiple production lines from a single manager module; either of the same product type and test routines as well as for a completely different product line with its own testing routines.

Until the invention of the Microflown sensor, acousticians were limited to the use of microphones to quantify sound. Being a scalar value, sound pressure provides information about the magnitude and phase of the sound field at the measurement location. Unlike sound pressure, particle velocity is a vector quantity and is thus described by magnitude and phase, as well as direction. Measuring three-dimensional particle velocity at one single spot in the sound field would provide a better description of a sound wave‘s physical behavior, as compared to the same measurement based only on sound pressure. Moreover, the physical behavior of particle velocity coupled with the unique features of the Microflown sensor, allow for accurate measurements under non-anechoic conditions, such as office spaces, test facilities, or even manufacturing environments. The two most important benefits are explained in the near field effect and directivity.

Measurement of normal particle velocity close to a surface of a sound source is less affected by background noise than a sound pressure measurement would be. This effect is caused by the near-field properties of a sound source. Such phenomena are referred to as the near-field effect. In order to understand the implications of the near field effect we will study two scenarios:1. First, consider a non-vibrating surface in an environment where background noise is present. Measuring sound pressure under such conditions, while gradually decreasing the distance between the measurement point and the rigid surface would result in continuous increase of the amplitude of sound pressure – sound will reflect off the rigid surface and cause an increase of sound pressure at the boundary. In contrast, normal particle velocity would behave in an exactly opposite fashion. Its amplitude would decrease in the proximity of a rigid surface.2. Second, consider a vibrating surface (a sound source) in an environment where background noise is not present. Measuring sound pressure in such conditions, while gradually decreasing the distance between the measurement point and the surface of the sound source, would result in a linear increase of the sound pressure level. In the case of the same experiment carried out with particle velocity, we would notice an exponential increase of the velocity near the source surface. This increase of amplitude is so significant, that it becomes the dominant source of excitation, largely suppressing external sound sources.

Whereas most sound pressure microphones have a omni-directional sensitivity pattern, the Microflown particle velocity sensor has a broad-banded figure-of-eight sensitivity pattern. Thanks to its directivity pattern, the Microflown sensor disregards 1/3 of the total sound field.