The master's work has been done to improve the process of ultrasonic welding copper connections. During the welding process, cracks appear on certain parts of the workpiece due to vibrations. Welded joints must be tested by the pulling force, the joint is loaded to peel. The customer demands a minimum peel force of 214 N to break the weld and workpiece without crack. Process optimization was done with using the design of experiment method. The experiments focused on the influence of the welding process parameters on the mechanical strength of the weld and the appearance of cracks. Changing the parameters only partially improves the welding process, so during the experiments, design improvements of the welding template, anvil and the workpiece were made, which further help to optimize and achieve the goals. With additional experiments of the selected main parameters obtain the optimal process parameters.