## 2 Materials and Methods  
The experimental setup is shown in Figure 1. The test series were carried out with the power source Plasmastar 500, a standard welding torch (type Plasmastar MV230) in combination with the powder feed unit Plasmastar PFII. The relative movement was realized by a 6-axis welding robot type Reis RV20-16.  
The advantage of the PTA process in the context of additive manufacturing is its high flexibility due to a huge number of setting parameters, which can be adjusted mostly independently of each other [9]. The lack of a direct link from the added feedstock mass to the added welding power is an example of this. This is an advantage compared to other arc-based process variants, especially for a multi-material additive manufacturing application with different raw material properties. To visualize the system complexity, Figure 2 shows all parameters that can be varied before or during the building process and forms the basis for the subsequent system analysis.  
The system analysis of the PTA process was based on the specifications of the DoE method. The aim of these was to prioritize the parameters shown in Figure 2, asking the question, \"Which parameters can be used during the construction process to affect the component geometry directly?\" Parameters which correspond to this criterion are defined as control factors. To achieve this, first the process was analyzed in general, then the determined system variables were prioritized and finally control factors were defined. The control factors identified as relevant are the welding speed, the welding current and powder mass flow. The investigation of the control factors was carried out by means of a 2-level full-factorial experimental design with a centered reference point. The settings of the reference parameters were determined in systematic preliminary tests [21]. The parameters of the reference point [21] and the changes of the control factors (see bracketed values) are shown in Table 1.  
Figure 1: Experimental setup of the additive process 3 DPMD.  
Figure 2: Setting parameters of the PTA process.  
Demonstrator components in hollow cuboid design with the dimensions \(b^{\pi}\)!\(h\) = 25\({}^{\circ}\)110\({}^{\circ}\)20 mm were produced to determine the relationships. An argon gas-atomized powder of the alloy 316L (X2 CrNiMo17-12-2), particle size 50-150 \(\upmu\)m with a spherical shape, was used for all tests.  
The evaluation of the part geometry was based on metallographic cross sections. In order to avoid random deviations, three cross sections per component, which are distributed around the circumference of the component, were produced and optically evaluated. The metallographic preparation followed the standard procedure according to ASTM E3-95 [22]. The measurement of the cross sections was carried out with an optical microscope (Zeiss) with integrated evaluation unit. To measure the component temperature during the build-up process, a combination of two pyrometers was used. In order to measure the entire temperature range, the IGAQ 10-LQ Impac two color pyrometer with a measuring range of \(T\) = 300-1000 \({}^{\circ}\)C was supplemented by a narrow-band METIS MQ11 pyrometer (\(T\) = 750-1800 \({}^{\circ}\)C). To display the size of the melt pool, a high-speed camera system (Phantom V7) with a frame rate of \(f\) = 2000 Hz in combination with a laser illumination unit was used.