Influence of Size Effect in Milling of a Single-Crystal Nickel-Based Superalloy

Abstract

This paper details an experimental investigation on the influence of the size effect when slot-milling a CMSX-4 single-crystal nickel-based superalloy using 1 mm- and 4 mm-diameter TiAlN-coated tungsten carbide (WC) end-mills. With all tools having similar cutting-edge radii (re) of ~6 µm, the feed rate was varied between 25–250 mm/min while the cutting speed and axial depth of cut were kept constant at 126 m/min and 100 µm, respectively. Tests involving the Ø 4 mm end-mills exhibited a considerable elevation in specific cutting forces exceeding 500 GPa, as well as irregular chip morphology and a significant increase in burr size, when operating at the lowest feed rate of 25 mm/min. Correspondingly for the Ø 1 mm micro-end-mills, high levels of specific cutting forces up to ⁓1000 GPa together with severe material ploughing and grooving at the base of the machined slots were observed. This suggests the prevalence of the size effect in the chip formation mechanism as feed per tooth/uncut chip thickness decreases. The minimum uncut chip thickness (hmin) when micromilling was subsequently estimated to be less than 0.10 re, while this increased to between 0.10–0.42 re when machining with the larger Ø 4 mm tools.

Creation of an Aluminum Alloy Template with a Surface Structure by Micro-Milling for Subsequent Replication of the Microstructure to Achieve Hydrophobicity

“…Using multi-axis control, complex contours can be machined with excellent continuity of different pattern structures. Technological stability and relatively simple process control principles allow the use of micro-milling in the fields of medicine (production of chips for insulin pumps, various parts of implants, and dentistry), electrical engineering, and watchmaking [13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Effects of Oil Concentration in Flood Cooling on Cutting Force, Tool Wear and Surface Roughness in GTD-111 Nickel-Based Superalloy Slot Milling

“…When machining nickel-based superalloys, different types of tool wear-like mechanical wear, adhesive wear, diffusion wear, and oxidation wear-become notably more pronounced and challenging [10][11][12]. Furthermore, extremely precise tolerances must be maintained concerning the components' geometry, a factor significantly influenced by tool wear [13][14][15]. The presence of a substantial amount of metal carbides (MC, M 23 C 6 ) in the raw material further exacerbates tool wear [16].…”

Effects of Machining Parameters and Tool Reconditioning on Cutting Force, Tool Wear, Surface Roughness and Burr Formation in Nickel-Based Alloy Milling

“…In the context of machining Ni-based superalloys, various forms of tool wear, such as mechanical wear, adhesive wear, diffusion wear and oxidation wear, become significantly more pronounced and problematic [7,8]. In addition, very strict tolerances must be observed with respect to the geometry of the components, which is greatly affected by tool wear [9][10][11]. A high content of metal carbides (MC, M 23 C 6 ) in raw material further increases tool wear [12].…”