Burr formation and surface roughness characteristics in micro-milling of microchannels

Chen, Liang; Deng, Daxiang; Pi, Guang; Huang, Xiang; Zhou, Wei

doi:10.1007/s00170-020-06170-4

Cited by 31 publications

(8 citation statements)

References 32 publications

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“…As the cutting-edge transitioned to down-milling commencing at the centre of the slot, the chip thickness reduced from a maximum value to zero at the end of the tooth–workpiece engagement, leading to diminished shearing but greater material side flow. Hence, larger burrs were observed on the down-milling side of the slot [ 41 ]. However, the discrepancy between the up- and down-milled sections became less apparent as the level of burring increased with the progression of tool wear, which led to higher chip extrusion and ploughing at both edges of the slot walls.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2023

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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.

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Section: Resultsmentioning

confidence: 99%

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

et al. 2023

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“…Mechanical micro-machining is capable of achieving unique features and small tolerances with various materials, including hardened steel, Inconel, aluminum, and polymer composites [ 47 , 48 , 73 , 74 ]. However, there are real-time challenges of chip removal in micro-sizes, tool deformation, burr formation, and vibrations [ 47 , 75 , 76 ]. Figure 4 shows some of the micro-milling procedures: down-, groove-, and up-milling, burr formation, and the problem of tool deflection while milling thin-walled structures.…”

Section: Alternative Micro-feature Fabrication Processesmentioning

confidence: 99%

“… ( a ) Schematic of micro-channel machining [ 47 ], ( b ) formation of burrs [ 76 ] and ( c ) deflection of micro-tool [ 75 ]. Copyright granted by Elsevier and Optica Publishing Group.…”

Section: Figurementioning

confidence: 99%

Electropolishing and Shaping of Micro-Scale Metallic Features

2022

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Electropolishing (EP) is most widely used as a metal finishing process. It is a non-contact electrochemical process that can clean, passivate, deburr, brighten, and improve the biocompatibility of surfaces. However, there is clear potential for it to be used to shape and form the topology of micro-scale surface features, such as those found on the micro-applications of additively manufactured (AM) parts, transmission electron microscopy (TEM) samples, micro-electromechanical systems (MEMs), biomedical stents, and artificial implants. This review focuses on the fundamental principles of electrochemical polishing, the associated process parameters (voltage, current density, electrolytes, electrode gap, and time), and the increasing demand for using environmentally sustainable electrolytes and micro-scale applications. A summary of other micro-fabrication processes, including micro-milling, micro-electric discharge machining (EDM), laser polishing/ablation, lithography (LIGA), electrochemical etching (MacEtch), and reactive ion etching (RIE), are discussed and compared with EP. However, those processes have tool size, stress, wear, and structural integrity limitations for micro-structures. Hence, electropolishing offers two-fold benefits of material removal from the metal, resulting in a smooth and bright surface, along with the ability to shape/form micro-scale features, which makes the process particularly attractive for precision engineering applications.zx3

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“…One of the earliest applications for the micro-milling process was in micro-structure and micro-component fabrication, which included blades of an impeller or turbine, walls of a microchannel, microcolumns, and fins of a heat exchanger. Presently, these microstructures have been widely applied in micro-fuel cells [1], microfluidic chip channels [2], electrical discharge machining (EDM) electrodes [3], microchannels for heat exchangers [4], and mass sensing in microelectromechanical system (MEMS) devices [5]. A key area for micro-milling is the mould making, which takes advantage of the high material removal rate to allow for cost effective manufacturing of moulds with high aspect ratio microstructures.…”

Section: Introductionmentioning

confidence: 99%

Optimal tool design in micro-milling of difficult-to-machine materials

O’Toole

2022

Adv. Manuf.

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The limitations of significant tool wear and tool breakage of commercially available fluted micro-end mill tools often lead to ineffective and inefficient manufacturing, while surface quality and geometric dimensions remain unacceptably poor. This is especially true for machining of difficult-to-machine (DTM) materials, such as super alloys and ceramics. Such conventional fluted micro-tool designs are generally down scaled from the macro-milling tool designs. However, simply scaling such designs from the macro to micro domain leads to inherent design flaws, such as poor tool rigidity, poor tool strength and weak cutting edges, ultimately ending in tool failure. Therefore, in this article a design process is first established to determine optimal micro-end mill tool designs for machining some typical DTM materials commonly used in manufacturing orthopaedic implants and micro-feature moulds. The design process focuses on achieving robust stiffness and mechanical strength to reduce tool wear, avoid tool chipping and tool breakage in order to efficiently machine very hard materials. Then, static stress and deflection finite element analysis (FEA) is carried out to identify stiffness and rigidity of the tool design in relation to the maximum deformations, as well as the Von Mises stress distribution at the cutting edge of the designed tools. Following analysis and further optimisation of the FEA results, a verified optimum tool design is established for micro-milling DTM materials. An experimental study is then carried out to compare the optimum tool design to commercial tools, in regards to cutting forces, tool wear and surface quality.

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Burr formation and surface roughness characteristics in micro-milling of microchannels

Cited by 31 publications

References 32 publications

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

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

Electropolishing and Shaping of Micro-Scale Metallic Features

Optimal tool design in micro-milling of difficult-to-machine materials

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