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  1. Nickel-based superalloys belong to a category of material employed for extreme conditions and exhibit high strength properties at elevated temperatures that result in poor machinability. Machining such di cult-to-cut materials like Inconel 718 leads to a high rate of tool wear, and therefore trochoidal milling toolpath is used to improve productivity and tool life. The current study analyzes the evolution of the flank wear area of the tool during trochoidal milling of Inconel 718 using an image processing methodology. It is attempted by performing experimental studies until tool failure occurs at several cutting conditions. The machining is performed through several iterations on an identical cutting path, and the number of iterations to failure is recorded. The microstructural image of a flank wear area is captured upon each iteration and processed using an image processing algorithm. It is realized that the evaluation of flank wear area can be an e ective parameter to analyze tool wear. Also, the image processing methodology works e ectively and can be extended during real-time machining. 
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  2. The machining of nickel-based superalloys such as Inconel 718 still poses a great challenge. The high strength and temperature resistance of these materials lead to poor machinability, resulting in high process forces and extensive tool wear. However, this wear is stochastic when reaching a certain point and is di cult to predict. To generate consistent wear conditions, the tool wear can be decoupled from the milling process by creating artificial wear using grinding. In this paper, a multi-axis approach for decoupling tool wear is presented and analyzed. Therefore, scanning electron microscope images of di erent wear states – worn and artificially worn – are analyzed. In addition, the occurring process forces of naturally and contrived worn inserts are compared in orthogonal cutting experiments as an analogy setup. Finally, a finite element analysis using a novel methodology for segmenting relevant cutting edge sections using digital microscope images provides qualitative insights on the influence of different wear conditions. 
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  3. Trochoidal milling is an alternative path planning strategy with the potential of increasing material removal rate per unit of tool wear and therefore productivity cost while reducing cutting energy and improving tool performance. These characteristics in addition to low radial immersion of the tool make trochoidal milling a desirable tool path in machining difficult-to-cut alloys such as nickel-based superalloys. The objective of this work is to study the dynamic stability of trochoidal milling and investigate the interaction of tool path parameters with stability behavior when machining IN718 superalloy. While there exist a few published works on dynamics of circular milling (an approximated tool path for trochoidal milling), this work addresses the dynamics of the actual trochoidal tool path. First, the chip geometry quantification strategy is explained, then the chatter characteristic equation in trochoidal milling is formulated, and chatter stability lobes are generated. It is shown that unlike a conventional end-milling operation where the geometry of chips remains constant during the cut (resulting in a single chatter diagram representing the stability region), trochoidal milling chatter diagrams evolve in time with the change in geometry (plus cutter entering and exiting angles) of each chip. The limit of the critical depth of cut is compared with conventional end milling and shown that the depth of cut can be increased up to ten times while preserving stability. Finally, the displacement response of the cutting tool is simulated in the time domain for stable and unstable cutting regions; numerical simulation and theoretical results are compared. 
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