3-D printing 1 3D-printing 1 Additive Manufacturing 1 Additive technology 1 Additives 1 Geometric Accuracy 1 Geometric accuracy Individual factors 1 Laser heating 1 PA12 1 Pa12 1 Polymer powders 1 Powder material 1 Property 1 Research focus 1 Selective Laser Sintering 1 Selective laser sintering 1 Sintering 1 Surface roughness 1