## 1 Introduction
From the experiments, it was shown that the dimensional accuracy of the ME parts was improved significantly using this method. [PERSON] [24] had done a literature review about the dimensional accuracy of ME parts. It was summarized that dimensional accuracy of the built parts was dependent upon the processing parameters and the properties of the feedstock filament properties. Particularly, the contours and layer height played key roles in determining the parts' dimensional accuracy. [PERSON] [25] analyzed the dimensional accuracy of ME parts made of ABS-plus material in order to establish the dimensional tolerance ranges. The effect of two processing parameters (the infill density and layer height) on the dimensional accuracy was experimentally studied. It was concluded that the optimum configurations for the fabrication of ME parts with ABS-plus was set up. The infill density was the most influencing factor. With the increasingly wider application of ME products in actual working conditions, the study in terms of vibration characteristics requires urgent attention. However, very few investigations have been focused on this research area, and the built parts' reliability can hardly be determined, especially in actual working conditions, such as machining, transportation, etc. [PERSON] [26] used the DMA2980 equipment to conduct the frequency sweep test on ME samples from 1 to 100 Hz to determine their modulus, damping and viscosity values. The results illustrated that the strength of the part processed with the solid built style was higher than those fabricated with other built styles. Increasing temperature would increase their loss modulus, but decrease the viscosity values and storage modulus. [PERSON] [27; 28; 29] used the same test method to investigate different processing parameters' effect on the dynamic elastic modulus of samples, and pointed out that modulus values would decrease when the build direction, raster angle or air gap increased. In addition, the numerical values of maximum glass transition temperature and dynamic modulus were determined by optimizing the processing parameters. [PERSON] [30] studied the effect of processing and testing parameters on the dynamic response of ME samples. Dynamic mechanical analysis (DMA) was used to determine the storage and loss modulus under an oscillating load. The results showed that the number of contours was the most influential parameter. Processing parameters (nozzle diameter, air gap and number of contours) could control the storage modulus of the manufactured parts, and testing parameters(temperature, loading frequency, and amplitude) showed a great influence on their damping capacity. [PERSON] [31] performed a series of tests to investigate the dynamic behavior of ME parts made of polyethylene terephthalate glycol (PETG) and PETG reinforced with 20% carbon fibers. The results revealed that the loss factor and damping obtained from the cyclic compression and models tests dropped from 17.3% to 15.4% and 13.8% to 12.3%, respectively. Although the above studies were carried out under vibratory and cyclic conditions, the dynamics inherent characteristics of the samples were not taken into account, i.e., natural frequency and mode shape. Furthermore, the existing research mainly relies on experimental testing, and lacks theoretical basis and principle. In this paper, a theoretical model was established and experimental research was performed to quantify the influence of different processing parameters on the dynamic inherent characteristics of ME plates. The sample preparations are introduced first, followed by the theoretical analysis and experimental tests. The samples' material properties are then provided, and the effect of three processing parameters on the dynamic characteristics is quantified through the comparison between predictions and measurements.