<![CDATA[A dynamometer is an instrument used to directly measure the cutting force generated during a CNC milling process. Politeknik Negeri Lhokseumawe currently does not have a dynamometer to support laboratory practice and cutting-force research, so the development of an economical octagonal-ring-based dynamometer structure is required. This study applies parametric modeling based on Visual Basic for Applications (VBA) macros in SolidWorks to automate dimensional variation of the octagonal ring, and analyzes the effect of geometric variation on sensitivity, stress, factor of safety, stiffness, and natural frequency using Finite Element Analysis (FEA). Three geometric parameters were varied—side length (l), ring thickness (t), and ring width (b)—across seven dimensional combinations, each tested under fifteen loading scenarios (Fx, Fy, Fz at five points), producing 105 simulations. The VBA macro successfully automated parameter updates, model rebuilding, and simulation execution without manual intervention. Variation V1 produced the highest sensitivity but FOS 1, whereas variation V4 (l = 18 mm, t = 4 mm, b = 18 mm) was selected as the optimal design, increasing average sensitivity by 20% (Fx), 26.67% (Fy), and 35.29% (Fz) compared with the initial design, while maintaining a minimum factor of safety above 2 and a natural frequency of 130.49 Hz. This optimal design can serve as a reference for developing a physical dynamometer to support CNC milling machining practice and research]]>
