## 3 Mechanical Vibration Tests
### Electromagnetic Clamping Systems  
Electromagnetic chucks or clamps (Figure 12) work using electromagnetism via a coil with a ferromagnetic core. Direct current (DC) through the coil magnetizes the core, creating a strong magnetic field to hold ferrous materials. These chucks consist of insulated wire coils wound around a ferromagnetic core to enhance the magnetic force. The magnetic field is controlled by a unit that enables quick magnetizing and demagnetizing.  
The clamping force generated by electromagnetic clamps (chucks) per 1 cm\({}^{2}\) of the clamping surface depends on the design and specifications of the particular electromagnetic clamp in use. There is no universal clamping force value that applies to all electromagnetic clamps, as the force generated can vary significantly based on such factors as the size of the clamp, the strength of the magnetic field, and the current passing through the coil. However, the analysis of catalogue data for various electromagnetic chucks indicates holding forces in the range of 100...150 N/cm\({}^{2}\)[36].  
The clamping force was also experimentally tested on the same rig as used for the testing of the vacuum clamp, with a steel plate measuring 100 \(\times\) 150 mm. The obtained average break force equaled 5000 N, resulting in maximum fastening force of 33.3 N/cm\({}^{2}\). This value was significantly lower than the catalogue value, due to the intentional use of a thinner yet lighter than recommended steel plate, to avoid oversizing the mass of the entire clamping device.  
The masses of electromagnetic chucks are quite high due to the ferromagnetic materials used in their fabrication, as well as the thickness, which for medium-height chucks range from a few centimeters to several centimeters. For example, the type EMU electromagnetic  
Figure 12: View of the (**a**) electromagnetic chuck [36] and (**b**) the one without a cover [37].  
chucks from BRAILLON MAGNETICS SAS [38] have a thickness range from 77 to 90 mm. An analysis of catalogue data for the weight of electromagnetic chucks of different holding areas (ranging from 200 \(\times\) 600 mm to 600 \(\times\) 1500 mm) yielded an average electromagnetic chuck mass per 1 cm\({}^{2}\) of holding area equal to 0.055 kg/cm\({}^{2}\) (results ranged from 0.049 to 0.060 kg/cm\({}^{2}\)).  
The advantages of electromagnetic chucks are as follows:  
* Strong holding power: can securely hold ferrous materials due to a strong magnetic field;
* Versatility and controllability: ability to hold different materials, with a control unit for easy activation or deactivation of the magnetic field;
* Adjustable holding force: the magnetic field's strength can be adjusted to suit specific workpiece requirements;
* A uniform and consistent clamping force across the entire workpiece surface. The disadvantages of electromagnetic chucks include the following:
* Quite high thickness and mass of the clamp, i.e., a 60 \(\times\) 60 cm electromagnetic clamp weighs about 200 kg and is about 7-8 cm thick;
* Continuous power requirement: need a constant power supply, with backup necessary to prevent de-clamping during outages;
* Heat generation: prolonged use causes heat buildup in coils, affecting performance;
* Maintenance needs: require cooling and regular maintenance for reliable operation;
* Power and thermal management: careful attention to power and thermal aspects for efficient and safe operation is necessary;
* The cost of purchasing and installing can be relatively high.