Recent Developments in Mechanical Ultraprecision Machining for Nano/Micro Device Manufacturing

Abstract

The production of many components used in MEMS or NEMS devices, especially those with com-plex shapes, requires machining as the best option among manufacturing techniques. Ultraprecision machining is normally employed to achieve the required shapes, dimensional accuracy, or improved surface quality in most of these devices and other areas of application. Compared to conventional machining, ultraprecision machining involves complex phenomenal processes that require extensive investigations for a better understanding of the material removal mechanism. Materials such as semiconductors, composites, steels, ceramics, and polymers are commonly used, particularly in devices designed for harsh environments or applications where alloyed metals may not be suitable. However, unlike alloyed metals, materials like semiconductors (e.g., silicon), ceramics (e.g., silicon carbide), and polymers, which are typically brittle and/or hard, present significant challenges. These challenges include achieving precise surface integrity without post-processing, managing the ductile-brittle transition, and addressing low material removal rates, among others. This review paper examines current research trends in mechanical ultraprecision machining and sustainable ultraprecision machining, along with the adoption of molecular dynamics simulation at the micro and nano scales. The identified challenges are discussed, and potential solutions for addressing these challenges are proposed.

Keywords: brittle and hard materials; ductile regime machining; minimum quantity lubrication; sustainable manufacturing; ultraprecision machining.

Figure 1

Traditional (conventional) and non-traditional machining techniques.

Figure 2

Taniguchi’s chart for the prediction of the development of machining accuracy [22].

Figure 3

Ultraprecision machining classifications.

Figure 4

Geometrical machining model: modified from [40].

Figure 5

Cutting of brittle and/or hard materials at the nanoscale: complex phenomena involved, redrawn and modified from [58].

Figure 6

Schematic model for subsurface damage mechanism in silicon during ductile machining [73].

Figure 7

Interferometer measurements of surface form error after fine correction. Process I: grinding, polishing and smoothing, and fine correction; process II: grinding, ultraprecision grinding (UPG), polishing, and fine correction [79].

Figure 8

Comparison of relative process times of process chains I and II split into the respective process steps [79].

Figure 9

Raman spectroscopy examination of the finely ground silicon wafer at etching depths of (a) 0 nm, (b) 30 nm, (c) 55 nm, (d) 110 nm, (e) 135 nm, and (f) 242 nm [82].

Figure 10

Process parameters and output parameters of AWJ [90].

Figure 11

Schematic LAT (a) and experimental set-up of LAT (b).

Figure 12

(a) Laser-assisted milling process experimental setup (1: rotary stage for orienting the laser, 2: stacked linear stages—X, Y and Z, 3: spindle assembly, 4: fibre optic cable, 5: collimator and micrometer assembly); adapted from [105]; (b) Laser-assisted microgrinding (I—schematic diagram; II—Experimental setup); adapted from [106].

Figure 13

(a) Schematic overview of µ-LAM; (b) single-point diamond turning µ-LAM [63].

Figure 14

Effect of higher laser power on the machined surface finish (a) and (b) effect of highly negative rake angle on the machined surface finish [63].

Figure 15

Crucial factors for consideration in sustainable manufacturing [118].

Figure 16

Characteristics of sustainable machining [124].

Figure 17

Sustainable manufacturing techniques for cleaner production: modified from [124].

Figure 18

Influence of lubrication conditions on (a) the surface roughness and (b) the grinding force of C_f/SiC at C = 5 g/L, P = 7 bar, Q = 80 mL/h, L = 60 mm [126].

Figure 19

Influence of concentration of carbon nanoparticles C on (a) the surface roughness and (b) grinding force of C_f/SiC composites at P = 7 bar, Q = 80 mL/h, L = 60 mm [126].

Figure 20

Influence of the fluid flow rate Q on (a) the surface roughness and (b) grinding force of C_f/SiC composites at C = 5 g/L, P = 7 bar, Q = 80 mL/h, L = 60 mm [126].

Figure 21

SEM images of (a) uncoated, (b) AlTiN-coated, and (c) TiAlN-coated WC micro end-mills in nano-MQL conditions with 1 vol% CuO after 450 mm cutting length [127].

Figure 22

The variation of average surface roughness with machining length by uncoated, AlTiN-coated, and TiAlN-coated WC micro end-mill in (a) dry, (b) pure MQL, (c) 0.25 vol% CuO nanofluid MQL, and (d) 1 vol% CuO nanofluid MQL conditions [127].

Figure 23

Nanometric cutting: MD simulation model, adapted from [136].