Analysis of the Forces in Micromilling of Hardened AISI H13 Steel with Different Grain Sizes Using the Taguchi Methodology

Abstract

The micromachining process has been applied to the free form and micromolds markets. This has occurred due to the growth in demand for microcomponents. However, micromachining of hardened steels is a challenge due to the reduction in tool life and the increase of the surface roughness when compared with the macromachining process. This paper focused on the analysis of micromilling forces on hardened AISI H13 steel with different grain sizes. Experimental tests were carried out on workpieces with different austenitic grain sizes and a hardness of 46 HRC. Micro-end-mill cutters with a diameter of 0.5 mm and (TiAl)N coatings were applied in the milling of workpieces of 11 × 11 mm. The input parameters were two radial depths of cut, two cutting speeds, and two feed rates. The influence of the input parameters on the response cutting force was analyzed using the Taguchi method. Finally, considering the large grain size, the cutting forces in the x-, y-, and z-axes direction were small.

Influence of Workpiece Hardness on Tool Wear in Profile Micro-milling of Hardened Tool Steel

“…Based on literature sources, mentioned cutting edge radius is very significant factor. Increase of mentioned radius causes phenomena of size effect and related negative phenomena which is not found in machining on macro level [20].…”

A review on micro-milling: recent advances and future trends

“…Micro-milling is a precise and flexible technology to manufacture complex 3D geometries in various types of materials (metals and its alloys, polymers, ceramics, graphite, composites etc. [3,[26][27][28][29][30][31][32][33][34][35][36][37][38]) by relatively high material removal rates. The kinematic of micro-milling is similar to the conventionalsized milling process; however, there are some unique phenomena and key issues: (i) the size of the cutting tool can be extremely small (diameter of 25 μm [39] or 50 μm [40]), the length-to-diameter ratio is therefore often high.…”

“…Micro-machining researches are carried out in a wide range of materials, with a very significant proportion of the research being steels, which is the most widely used metal in the engineering world. For the sake of example, many researchers studied micro-machinability of AISI 1045 (partly as reference material) [4,38,46,77,88], different stainless steels [43,84,114], and also hardened steels [29,30,84,157]. Several researchers have also investigated aluminium micromachining [95,109,125,142].…”

“…In the captured images, the tool can be in any positions, and the algorithm can evaluate it correctly. This is based on the fact that the size of the tool (which perpendicular to the cutting edges of the tool) does [4], [33], [38], [46], [48], [51], [54], [83], [88], [89], [122], [133], [144], [164], [165], [166], [167], [168] AISI 1015: [169] AISI 1018: [125] AISI 1040: [77] AISI 1050: [37] AISI 4340: [119], [139], [170] AISI P20: [20], [145], [164] S960QL: [171] NAK80: [123], [172], [173], [174] AISI A2-annealed: [175] 42CrMo4: [167] X13NiMnCuAl4-2-1-1: [146] SK2: [176] Hardened steels AISI H13: [2], [30], [42], [72], [80], [164], [177], [178], [179],…”

Material microstructure effects in micro-endmilling of Cu99.9E

“…Lauro et al 29 conducted experimental trials to assess micro-milling forces when machining hardened steel with different grain sizes. It was found that feed rate was the most significant factors affecting the cutting force, that is, large grain sizes led to lower cutting forces.…”