This two-part paper presents the results from modeling and optimization of alternative sustainable machining processes of Inconel 718. Nickel and Titanium, as representatives of high temperature alloys, with their specific thermo-mechanical properties, pose significant difficulties in machining. The high temperature and the consequent work hardening of these materials during the machining processes adversely affect cutting forces, tool-wear, surface integrity and chip breakability. This first part (Part 1) of the paper presents the experimental study of sustainable high performance machining of Inconel 718 with the development of performance-based predictive models for dry, near-dry (MQL), cryogenic and cryo-lubrication (cryogenic + near-dry) machining processes using response surface methodology (RSM). The robustness of these models was verified using the ANOVA. Cutting forces, surface roughness and tool-wear were measured, analyzed and modeled. The results show that the cooling/lubrication condition has an influence on machining performance and that optimum machining conditions have to be determined, at which an improved overall machining performance can be achieved, while sustainability directions are followed in terms of reducing cutting forces/power consumption, the prolonging of tool-life, and increasing productivity. The models developed in the first part of the paper are used for process evaluation and optimization in the second part, to determine optimum machining conditions for an overall process performance improvement.
COBISS.SI-ID: 13552667
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. The work shows that 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. Moreover, it offers a significant improvement in final product performance, and fatigue life.
COBISS.SI-ID: 13457691
Machining with robots represents a promising, highly flexible and cost effective alternative to standard machining and hand labour applications when machining mid tolerance soft material end products. One of the most challenging issues is to know the vibration characteristics in milling with the robots which greatly affect tool life. In general, the technological bases of tool life expectancy while milling with robot arms are not available or studied. That`s why the purpose of this paper is to investigate the influence of attained vibrations analysis during the milling process and correlated tool wear. Primarily the study is focused on tool wear according to the distance between the milling position and the robot`s base. Results show that increasing distance between the robot's base and the milling position significantly affects tool wear because of the attained vibrations in proportion to the increasing distance respectively. Tool wear has also proved to be greater in comparison to machining with CNC machine and applicable new information for woodworking industry.
COBISS.SI-ID: 13789467