This paper investigates the impact of algorithms for trajectory interpolation in collaborative robot painting processes on energy efficiency and operational execution time. The study aims to develop an algorithm for trajectory planning that works with complex geometric details and identifies a suitable trajectory interpolation method for synthesizing the painting control program. MATLAB is used for software implementation. Analytical geometry methods and affine transformations are employed to generate the spray gun trajectory based on child geometry and technological requirements. Various interpolation techniques (spline, makima, and pchip) are examined for their effectiveness in creating smooth trajectories in joint space, minimizing deviations from the intended path. The results demonstrate significant variations in energy consumption and trajectory deviations between the different interpolation methods. CubicSmooth/spline demonstrated the best performance in minimizing energy consumption and deviation from the planned trajectory. The trajectory calculated by the algorithm proved its operability and adherence to technological requirements. Our findings emphasize the significance of selecting appropriate interpolation algorithms based on the specific requirements of the technological process in order to optimize robot performance and energy efficiency. Future research will focus on extending the range of robotic applications and trajectory shapes while considering safety measures for collision avoidance.