## 3 Design of Test Plate  
In literature [5; 36] and in many more studies, authors investigated how processing parameters (for example, layer thickness, surface finish, and build location) influence dimensional accuracy, surface roughness and mechanical properties. A thin wall test plate (0.2-1 mm in intervals of every 0.1 mm) was suggested, but for the Polylet process, the distance between these thin walls is equally important as wall thickness itself. In our previous experiment, the measurement results revealed limitations of the Polyjet process when printing small raised and recessed L structures. It was determined that when the distance between structures is larger than 0.4 mm, the structures are printed in accordance with the CAD model. However, when the distance between structures is at the level of 0.3 mm or less,the PolyJet machine fails to print structures in accordance with the CAD model, i.e., structures are then printed only partially [17; 37]. Our study is aimed to investigate the dimensional stability of a part during printing in the same series in intervals. Due to that, the test plate was designed with fewer features than other reviewed designs. From our previous research, some limitations of the machine itself were identified. Holes with diameters smaller than 0.5 mm cannot be printed, either horizontally or vertically. Even larger holes, such as 1 mm in diameter, are not circular and deviations exist. L raised profiles with a spacing of less than 0.5 mm merge together, and PolyJet also cannot make tapered cone tips [37]. All test plates were printed in the same orientation, according to results stated in literature by [PERSON] et al. [15] to maximally avoid the influence of the machine and specificity of the process. In a study by authors [PERSON] et al. [38], it was found out that build styles (surface finish types and layer thickness) influence dimensional accuracy. Surface finish types can be matte and glossy. Better dimensional accuracy is obtained with matte surface and printing along the \(z\) axis, but printing with glossy finish type reduces material cost and the subsequent removal of the support [5]. For this reason, it was decided that the matte finish type will be used only for the holes in the \(X\)Z plane, and everything else will be glossy finish type. A big limitation of PolyJet technology is the likelihood of destroying the small parts that the machine can print while cleaning them with water. According to some of the rules described in the introduction and our pre-test, the test plate design is shown in Figures 2 and 3. The hole diameters in plane \(XY\) and \(X\)Z are 3, 2, 1.5, 1, 0.75 and 0.5 mm. The distance between the beginning of each hole is 2 mm. The channel diameter is 1.5 mm on one side of the plate and 1.0 mm on the other side. The base diameter and height of a cone are both 6 mm. In order to test the repeatability of the results, a plan for printing the test plates was made so that three identical test plates were made successively in each cycle. Test plates were made of _VeroBlack_ material on machine _Object Connex 350_ with resolution in of 600 dpi \(x\) and \(y\) axis and 1600 dpi in \(z\)-axis More information about the printer can be found in reference [39]. Slicing software and preparation of the model was done in _Object Studio_ which is the default of the 3D printer itself. Material requirements for three plates were 20 g of _VeroBlack_ material and 10 g of supporting structures/material _SUP 705_. The support material was removed by pressurized water. The production time was 1 h. Test plates were built with a layer thickness of 0.016 mm with glossy surface finish and with position and orientation in the working platform in the left upper corner shown in Figure 4. The temperature of the printing head was 70 \({}^{\circ}\)C and printing was performed at room temperature, 22 \({}^{\circ}\)C, and humidity 45%. Figure 2: 3D Computer aided design (CAD) model of test plate. According to [PERSON] et al.