The transition to a clean, dry, and energy efficient polishing process: an innovative upgrade of abrasive flow machining for simultaneous generation of micro-geometry and polishing in the tooling industry

On account of the current different requirements in the field of finishing/polishing, e.g., reducing the finishing time, process control, ensuring a clean process, and energy efficiency, hand polishing needs to be replaced with a superior process. One alternative is abrasive flow machining (AFM). In comparison with hand polishing, AFM is an efficient process, suitable for finishing external as well as internal surfaces, which are often complex and out of reach. Due to the drawbacks of AFM, in this work a novel method of abrasive flow machining with a movable mandrel (AFMmm) is proposed and introduced through a case study from the automotive industry. As in the manufacturing sector electric power consumption is the main driver that influences CO2 emissions, a comparative analysis of the energy efficiency of AFM vs. AFMmm is performed. The results of this work show that the application of the novel AFMmm method is capable of removing WEDM-damaged (wire electric discharge machining) surface and produces a polished surface under dry conditions, leaving the machined surface clean. Moreover, the novel upgrade of the AFM process can be significantly more energy efficient and with finishing is simultaneously able to control the micro-topography of the product. The gearing injection mold tool case study shows that the benefits are not related merely to the process, but also to the product. It offers a significant improvement in gear performance, energy efficiency in operation, as well as in fatigue life, which is extended by more than a factor of two. As a contribution, a novel clean and energy efficient AFMmm is presented, capable of synergistically shaping and polishing the geometry of the final product on a micro level and under dry conditions.