Experimental investigation of vibration of the shadow mask with different assembly conditions

In this paper, for different assembly conditions, the natural frequencies, mode shapes and amplitude fluctuation electronic speckle pattern interferometry (AF-ESPI) fringe patterns of the shadow mask were obtained and used to visualize the difference among the assembly conditions. Specimens of three groups including one original design, adding welds along the rims of the shadow mask in the direction of the horizontal axis and changing the thickness of the plate spring were investigated. From the AF-ESPI results, except the mode 3, the natural frequencies are increased by adding welding points along the rims in the direction of the horizontal axis. For the case of increasing the thickness of the plate spring, the natural frequencies of all modes are increased. Generally speaking, adding welds improve the vibration behavior for the third, fourth and fifth modes. The first and second modes, however, are predominated by the shadow mask. In addition, the vibration characteristics of the sixth mode is not improved by changing the assembly conditions.