Abstract-Technology of 3D-Printer based on fused deposition material has developed intensively with varying qualities. However, default setting of printing process parameters provided by the manufacturer in some cases does not guarantee quality (dimension error and strength) of the printed part, since there are several process parameters that need to be considered. A 3D-Printer with polylactic acid filament material has been applied in this study. A specimen standard of ASTM D638 Type IV has been used as a tensile strength and dimension error test to represent printed part quality. Keyword -3D-Printer, Optimization, Polylactic Acid (PLA), Taguchi Method, Response Surface Method I. INTRODUCTION Additive manufacturing (AM) or layer manufacturing (LM) technology and it is called 3D printer has developed intensively with varying material types and forms that can be used to build a 3D object. It is gaining ground for manufacturing prototypes, tools and functional end products [1]. Several of existing technologies include selective laser sintering/melting (SLS/M), laser-photo resin curing (SLA), laser-cutting of sheet material (LOM), fusing of melted filament material (FDM), electron beam melting (EBM) and many others. However, although these technologies have been available commercially, there are a wide range of qualities of the machine and the built part and so the price. Recently, the price of the machine is drop and even a small machine-FDM based technology in the kit pack is underway to become home appliances, just like coffee maker. Built part quality of 3D printer (FDM based technology) here is defined on the basis of mechanical strength, surface finish, and dimension error or dimension accuracy. Research related to the mechanical strength of printed parts built by 3D printer can be found in many publications. Tymrak, et.al. investigated tensile strength and modulus elasticity of PLA and ABS parts made by 4 types of open source RepRap 3D printer [2]. They used pattern orientation (0°/90°,+45°/45°) and layer thickness (0.2; 0.3; 0.4 mm) as printing parameters of printing object (ASTM D638). In this research, they found that the mean of tensile strength and modulus elasticity of PLA part were 56.6 MPa and 3368 MPa; while for ABS, there were 28.5 MPa and 1807 MPa, respectively. In relation to build orientation, Zaldivar et.al found that the orientation also affected thermal behaviour of 3D-Printed ULTEM 9085 Material [3]. By choosing suitable build orientation and reducing layer thickness, Singh Bual and Kumar could improve the surface finish of the printed part [4]. Similar research using FDM has also been done to investigate the combination effect of 5 raster angles (0°, 30°, 45°, 60° and 90°) and 3 part orientations (horizontal, vertical and perpendicular) to surface roughness, mechanical characteristic (tensile strength and flexural strength) of ABS printed part, production time and cost [5]. They found that raster angle and part orientation gave effect to surface roughness and mechanical characteristic. Amon...