This study explores the application of topology optimization to reduce the weight of a sliding arm in a mechanical effector mounted on a collaborative robot. The effector is designed to grasp PC motherboards, with the heaviest board weighing 5 kg. Given that the effector itself weighs 5 kg and the robot’s maximum payload is 10 kg, the system frequently operates at its limit, accelerating wear and reducing efficiency. Topology optimization was performed while preserving functional surfaces and structural integrity, achieving a 54% mass reduction (from 260 to 120 g) without compromising stiffness or safety factor. Finite Element Analysis (FEA) using Altair Inspire software confirmed a reduction in maximum displacement from 0.14 mm to 0.06 mm and an increase in the factor of safety from 15 to 18. The optimized arm was designed for Selective Laser Melting (SLM) with AlSi10Mg alloy, selected for its favorable weight-to-cost ratio and manufacturability. Future work includes experimental validation of the printed component. The results demonstrate that topology optimization combined with additive manufacturing can enhance collaborative robot efficiency by minimizing unnecessary mass without compromising mechanical performance or cost-effectiveness.