Laser vibrometers will help you to develop efficient tools for ultrasonic processing applications. Already used in various industries for applications such as wire bonding, welding and food cutting, Polytec vibrometers are essential for FE model validation and verification.
Polytec Scanning Vibrometers are perfectly suited for the verification of numeric simulations of ultrasonic welding tools. Its inherent properties like
- full-field measurements (1D and 3D)
- linear frequency response
- high frequnecy bandwidth
- geometry import from CAE
allow for a quick evaluation of the uniformity of deflection at the active surface.
Case Study: 3D Sonotrode measurement
Measured with PSV-400-3D Scanning Vibrometer
- 7,641 DOF / 2,547 measurement points
- Bandwidth: 100 kHz
- Nominal operating frequency: 20 kHz
The deflection shapes were measured in 5 sections, using mirrors to get optical access to the active surface.
For the measurements the sonotrode was positioned on a support plate. A mirror was placed below the sonotrode at 45 degrees. This arrangement allows the scanning laser vibrometer viewing and measuring the sonotrode active surface. The sonotrode was excited with a broadband periodic chirp signal from the PSV signal generator.
The object geometry with the nodes and elements was loaded into the PSV software. A simple referencing procedure (3D-alignment) aligned the sonotrode in order to match the numeric geometry to the object in the PSV video image.
Deflection Shape 20 kHz
The measured deflection shape at 20 kHz shows a well designed sonotrode: The active surface moves up and down very uniformly. There are hardly now parasitic modes visible.
Deflection Shape at 7 kHz
If the frequency is shifted away from the driving frequency, other modes become dominant. In the example at 7 kHz the deflection shape will introduce in-plane motion to the active surface, which is not desired in this case