Feasibility analysis and process characteristics of selective laser ablation assisted milling Inconel 718

Laser-assisted machining (LAM), as one of the most efficient ways, has been employed to improve the machinability of nickel-based superalloys. However, the conventional LAM process usually used high power laser with large spot size, easily leading to high processing costs and overheating of bulk materials. In this paper, a new approach of selective laser ablation assisted milling (SLA-Mill) process for nickel-based superalloys was proposed, in which low power laser with small spot size was used to selectively ablate the uncut surface in front of the cutting tool, resulting in plentiful surface defects emerging. Such defects would significantly weaken the mechanical strength of difficult-to-cut materials, which was different from the thermal “softening” principle of conventional LAM. Thus, the laser ablation effect with low power and small spot size was first studied. The relationship between process parameters (e.g., laser power, cutting speed and cutting depth) and process characteristics of SLA-Mill (e.g., chip morphology, tool wear and surface integrity) was systematically discussed. Moreover, the chip formation mechanism in the SLA-Mill process was indepth analyzed. Results show that the SLA-Mill process is an effective approach for enhancing the machinability of nickel-based superalloys. The resultant cutting force has a reduction of about 30% at laser power of 60 W, cutting speed of 90 m/min, and cutting depth of 0.1 mm. Furthermore, the chip formation, tool wear, and surface integrity have improved significantly. In general, this paper provides a new route for the application of LAM technology.