Fabrication of high aspect ratio free-standing structures using abrasive water jet micro-machining

Azarsa, Ehsan; Cinco, Lorenzo; Papini, M.

doi:10.1016/j.jmatprotec.2019.116318

Cited by 17 publications

(24 citation statements)

References 35 publications

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“…On one hand, AWJ machining applies very low cutting forces to the workpiece while the yielded thermal influence is negligible (Wei et al, 2019); hence, no thermal effect on the machined surface is expected. On the other hand, a high machining versatility, simplicity and cutting flexibility can also be obtained as the high pressure jet plume is utilised as a 'cutting tool' (Azarsa et al, 2020). Furthermore, as reported by Axinte et al (2009), the AWJ machining is also an economical process with high material removal rate at low cost, while it is virtually possible to cut almost any material.…”

Section: Introductionmentioning

confidence: 99%

Dual-processing by abrasive waterjet machining—A method for machining and surface modification of nickel-based superalloy

Liao

Sanchez

et al. 2020

Journal of Materials Processing Technology

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Abrasive waterjet (AWJ) is widely used for machining of advanced (e.g. nickel-based) superalloys as it offers high material removal rates and low cutting temperatures. However, the inadequate surface integrity, e.g. large number of scratches and embedded particles in the machined surface, which would induce severe deteriorations of the materials functional performance, has been one of the greatest issues of the AWJ machining technique. To solve this problem, this research proposed a dualprocess abrasive waterjet machining method, whereby two different functions of abrasive waterjet were employed: materials removal (first process) and surface modification (secondary process), hence, to improve the workpiece surface integrity. Two types of entrained particles, i.e. with sharp cutting edges (e.g. garnet) and smooth surfaces (e.g. stainless steel ball), that depending on their kinetic energy density can either cut or modify the workpiece surface respectively, are employed for these the two constitutive processes of the proposed dual-waterjet machining method. A critical standoff distance and inclination angle of the waterjet nozzle has been defined for the surface modification process thus, to eliminate the embedded particles and scratches left by the first cutting process while also introducing a surface strengthening effect. To support this approach, a mathematical model has been proposed for determining the surface modification parameters (e.g. jet feed speed and abrasive flow rate). In-depth analysis of the microstructural and metallurgical alternations of the machined workpiece surface and superficial layer have also been conducted to reveal the mechanisms responsible for the surface damage elimination and surface strengthening.Moreover, a four point bending fatigue test has been conducted to validate the mechanical performance, whereby a significant improvement of the fatigue life on the machined workpiece was achieved when compared with the case that single AWJ cutting method (91%) and conventional machining (34%) are employed. This proves that the proposed dual-processing AWJ machining method is of high efficiency to improve the functional performance of components on a single machine tool platform.

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Section: Introductionmentioning

confidence: 99%

Dual-processing by abrasive waterjet machining—A method for machining and surface modification of nickel-based superalloy

Liao

Sanchez

et al. 2020

Journal of Materials Processing Technology

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“…The setup used by Azarsa et al [87] was utilized for all of the AWJM processes. It included a micro-nozzle assembly with an orifice and mixing tube having diameters of 127 µm and 254 µm, respectively, and an in-house manufactured hopper with a gate valve to control the particle mass flow rate [95].…”

Section: Awjm Setupmentioning

confidence: 99%

“…AWJM utilizes high-pressure water passing through a small orifice in order to entrain dry abrasive particles and air. The resulting mixture passes through a micro-sized mixing tube at high speed, and can be used to perform controlled-depth micro-machining [27,87,88] on virtually any material. High-pressure ASJM entrains a slurry rather than dry abrasive, thus eliminating the effect of entrained air into the mixing tube, resulting in improved surface finish, although at the penalty of a reduced material removal rate [1].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Free-Standing Structures Using Abrasive/Slurry Jet Micro-Machining

Azarsa¹

2023

Preprint

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Many advanced engineering materials are machined using abrasive water jets, a non-traditional machining method that has certain advantages compared to other approaches. This dissertation aims at developing methodologies to use abrasive water and slurry jets to micro-machine free-standing structures for heat sink and microfluidics applications. The first aim was to fabricate high aspect ratio free-standing structures with a minimum distance between each other that would lead to maximum heat transfer performance in heat sinks. The effect of machining process parameters on the quality of the resulting free-standing structures was studied. It was demonstrated that high-quality free-standing structures with aspect ratios of more than 40 to be used as fins in heat sinks could be fabricated. There is an increasing demand for metallic micro-molds that can be used for inexpensive mass production of polymeric microfluidic chips. Therefore, the feasibility of using abrasive water jet micro-machining (AWJM) and abrasive slurry jet micro-machining (ASJM) to fabricate such micro-molds was studied. Jet raster scans under various combinations of process parameters were used in order to machine micro-pockets containing free-standing structures, representing molds for casting microfluidic chips with channel networks. The optimum process parameters and material were determined in order to fabricate the molds with the best possible surface finish. Because unmasked machining could not be used to fabricate molds with sharp-edged intersecting features, a hybrid AWJM/ASJM masked machining technique was introduced. By careful selection of the process parameters, high quality molds with both single and intersecting free-standing structures at multiple heights could be fabricated, thus making three-dimensional microfluidic chip mold fabrication feasible. Finally, a new method of mold fabrication that utilized water jet cutting technology to cut free-standing structures out of mild steel sheets, to be used as a mold for PDMS casting, was developed. This enabled 3D features having very abrupt changes in depth with almost 90o angles for use in microfluidic devices. As a proof-of-concept, a polydimethylsiloxane (PDMS) chip was made and tested. It was shown that this alternative approach to create microfluidic molds is versatile and may find utility in reducing the cost and complexity involved in fabricating 3D features in microfluidic devices.

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“…have been used to coat. Etching [9], layer-by-layer assembly [10], sol-gel chemistry [11], hydrothermal treatment [12], successive ionic layer adsorption and reaction (SILAR) [13], hydrothermal synthesis [14], electrochemical micromachining (EMM) [15], abrasive water jet micro-machining [16] [17] have been used to generate microstructures. However, fabrication of hydrophilic microstructures on glass while maintaining the transparency of the microstructured glass remains challenging.…”

Section: Introductionmentioning

confidence: 99%

Manufacturing of anti-fogging super-hydrophilic microstructures on glass by nanosecond laser

Yang

Luo

Chang

et al. 2020

Journal of Manufacturing Processes

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Fabrication of high aspect ratio free-standing structures using abrasive water jet micro-machining

Cited by 17 publications

References 35 publications

Dual-processing by abrasive waterjet machining—A method for machining and surface modification of nickel-based superalloy

Dual-processing by abrasive waterjet machining—A method for machining and surface modification of nickel-based superalloy

Fabrication of Free-Standing Structures Using Abrasive/Slurry Jet Micro-Machining

Manufacturing of anti-fogging super-hydrophilic microstructures on glass by nanosecond laser

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