###### Abstract  
Variation management in additive manufacturing (AM) is progressively more important as technologies are implemented in industrial manufacturing systems; hence massive research efforts are focused on the modeling and optimization of process parameters and the effect on final part quality. These efforts are, however, hampered by the very problem they are seeking to solve, as conclusions are weakened by poor validity, reliability, and repeatability. This paper details an elaborate experiment design and the subsequent execution with the aim of making the research data available without loss of validity. Test artifacts were designed and allocated to fixed positions and orientations in a grid pattern within the build chamber to facilitate rigid analysis between different builds and positions in the build chamber. A total of 507 specimens were produced over three builds by laser sintering PA12 before inspection with a coordinate measuring machine. This research demonstrates the inherent variations of laser-based powder bed fusion of polymers (LB-PBF/P) that must be considered in experiment designs to account for noise factors. In particular, the results indicate that the position in the xy-plane has a major influence on the geometric accuracy, while the position in the z-direction appears to be less influential. additive manufacturing; geometric tolerancing; part build orientation; powder bed fusion; selective laser sintering; PA12; PA2200 29 January 2020 20 February 2021 25 February 2021 25 February 2  
at a larger scale. Further classification of PBF is made by specifying the energy source and material type, i.e., electron beam or laser as the energy source, and metal, polymer, or ceramics as materials, as illustrated in Figure 1[5]. The current work reports on experiments on laser-based PBF of polymers (LB-PBF/P), popularly known as selective laser sintering (SLS). Layered manufacturing processes are generally prone to the so-called staircase effect arising from the discretization of a 3D surface into 2.5D layers. This inevitably affects the surface topography and accuracy [6]; hence the phenomena have been modeled in terms of both flatness [7] and cylindricity [8]. Because the severity of the staircase effect depends on the angle of the surface, the surface type plays a major role in how the staircase effect manifests, and therefore, also how the part builds orientation influences the geometric accuracy. In this context, a surface type may be any of the five geometric primitives--plane, cylinder, cone, sphere, and torus--and an occurrence of a surface type on a 3D-model is referred to as a shape feature. Because surface types are influenced differently by part build orientation, the shape features can be used to optimize part build orientation and to predict geometric deviations [9; 10]. Previous research has shown that PBF is a complex process with many variables affecting the product in terms of mechanical properties [11; 12; 13; 14; 15], surface quality [14; 15; 16; 17; 18; 19], and geometric and dimensional accuracy [15; 20; 21; 22]. The part build orientation is known to have a significant effect on final quality with regards to all of these areas in addition to its contribution to build time and cost [23]. Consequently, numerous studies include part build orientation as an experimental factor to gauge and model its effect on various measures [24]. While studies on surface roughness in various AM technologies have investigated part build orientations with 10- and 15-degree intervals [19], the effect on dimensional and geometric accuracy is typically not researched with the same level of detail. [PERSON] [21] performed a statistical analysis of dimensional accuracy in LB-PBF/P, where four orientations were utilized. [PERSON] et al. [25] conducted an experiment in LB-PBF/P with a central composite design where the effect of orientation on flatness and cylindricity was investigated in five levels from 0 to 90 degrees alongside several other factors.