High pressure abrasive slurry jet micro-machining using slurry entrainment

Haghbin, Naser; Ahmadzadeh, Farbod; Spelt, J.K.; Papini, M.

doi:10.1007/s00170-015-7769-8

Cited by 7 publications

(10 citation statements)

References 22 publications

(37 reference statements)

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“…These systems are distinguished by whether the abrasive is entrained into the flowing water as a dry powder in an air stream or whether it is entrained as a liquid slurry (e.g. Miller [5], Haghbin et al [6]). The work presented in this thesis focuses on UHP (ultra-high pressure) AWJ/micro-abrasive waterjet machining (µAWJM) using an abrasive-air injection system.…”

Section: Waterjet Technologymentioning

confidence: 99%

Predicting Surface Roughness and Delamination When Abrasive Waterjet Machining Fiber Reinforced Polymer Composites

Schwartzentruber¹

2023

Preprint

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The machining of composite materials is difficult because of their non-homogenous structure and their constituents commonly possess a high resistance to cutting. Abrasive waterjet machining (AWJM) is more attractive for composite substrates than conventional machining techniques because of its ability to rapidly machine a wide variety of materials with low reactionary forces on the workpiece, and without creating a heat-affected zone. However, AWJM is prone to producing variable surface roughness and delamination. This dissertation aimed to model these surface roughness and delamination mechanisms. The thesis presents 2D and 3D roughness models capable of predicting the surface roughness during abrasive waterjet (AWJ) trimming of composite substrates. The models were able to predict the measured surface roughness with an average error of 10% and 16%, for the 2D and 3D models, respectively. The thesis also presents experimental and numerical results characterizing the delamination when AWJ piercing and cutting a carbon-fiber/epoxy laminate. Fluid-structure interaction (FSI) models created to simulate the piercing process showed that interlaminar delamination was due to the hydraulic shock (‘water hammer’) associated with liquid jet impact. As expected, increased pressure and nozzle size resulted in ply debonding, and was experimentally verified using 3D x-ray micro-tomography. The composite anisotropy was found to produce an asymmetric shock loading along the liquid-solid interface, which contributed to the asymmetric delamination. The FSI model showed that delamination when cutting carbon-fiber/epoxy depended primarily on the normal interlaminar stress, with relatively large damage zones occurring ahead of the cutting front. This trend was also observed in x-ray micro-tomographs of an AWJ cut. The amount of delamination across different process parameters was also measured using a moisture uptake methodology, and showed that increase traverse speed, increased nozzle size, and decreased abrasive flow rate, increased delamination. Prediction and characterization of surface roughness and delamination when AWJM will allow further improvement of cut-surface finish and structural integrity of composite materials, respectively

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Section: Waterjet Technologymentioning

confidence: 99%

Predicting Surface Roughness and Delamination When Abrasive Waterjet Machining Fiber Reinforced Polymer Composites

Schwartzentruber¹

2023

Preprint

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“…Finally, the mixture enters into mixing tube and ultimately exits with speeds of generally 250-720 m/s. Abrasive slurry jet machining (ASJM), developed more recently by Haghbin et al [1] in the form that is used in this thesis, entrains a slurry rather than dry abrasive.…”

Section: Abrasive Water and Slurry Jet Machiningmentioning

confidence: 99%

“…As mentioned in Section 1.1, Haghbin et al [1] has recently developed a ASJM technique in which a slurry rather than dry abrasive enters inside the mixing tube, and the technique eliminates the effect of entrained air into the mixing tube. In contrast to traditional slurry setups, Haghbin et al [1] performed a simple modification to an existing commercial high-pressure water jet machine and the premixed slurry is not forced through an orifice, but instead entrained directly into mixing chamber. Therefore, by utilizing their new slurry device, it was possible to perform micromachining on both brittle and ductile materials without causing any significant damage to the nozzle components.…”

Section: Abrasive Slurry Jet Micro-machiningmentioning

confidence: 99%

“…The schematic of the setup can be seen in Figure 1-3. Haghbin et al [1] found that the entrained air in AWJM resulted in a relatively high waviness compared to ASJM due to variation in the abrasive flow rate in the air driven particle feeding system. They also found that in AWJM, the entrained air surrounds the peripheral area of the core jet, and causes an increase in the jet size, which may lead to a wider jet footprint than in ASJM.…”

Section: Abrasive Slurry Jet Micro-machiningmentioning

confidence: 99%

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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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“…Figure 18 shows the schematic of abrasive slurry jet micromachining process. In abrasive slurry jet micromachining (ASJM), pressurized water is used to accelerate the suspended abrasive particles such as garnet or aluminum oxide (Al 2 O 3 ) [35]. For the same jet dimension and flow speed, slurry jets have a much lower divergence angle than air jets, allowing for the micromachining of smaller features without the use of patterned masks.…”

Section: Abrasive Slurry Jet (Asj) Machiningmentioning

confidence: 99%

Advances in Nano-finishing of Optical Glasses and Glass Ceramics

Suresh¹,

Rasheed²,

Gupta³

2020

Handbook of Advanced Ceramics and Composites

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Optical glass and glass ceramic components with angstrom-level surface roughness and nanometer-level dimensional accuracy are in potential demand for sophisticated optical fabrication. In recent years, aspherical and free-form surfaces are gaining prominence for high-performance applications. Moreover, the new optical materials and fabrication process which exhibit superior mechanical properties are being developed to meet the stringent requirements and harsh environment. Fabrication of complex-shaped high optical finish components becomes a significant challenge as conventional finishing techniques are unable to machine aspherical or free-form surfaces precisely. This situation demands few highly advanced and precise finishing processes which ensure stress-free surfaces. Mostly, the optical components are fabricated by shaping or pre-finishing methods followed by final finishing processes. Final finishing processes include more deterministic and flexible polishing techniques that can achieve desired surface finish, figure accuracy and surface integrity to make it suitable for shorter wavelength applications. In this chapter, basic principle, mechanism of various material removal processes, and precision polishing techniques such as magnetorheological fluid-based finishing were discussed and are compared with the convention polishing techniques.

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High pressure abrasive slurry jet micro-machining using slurry entrainment

Cited by 7 publications

References 22 publications

Predicting Surface Roughness and Delamination When Abrasive Waterjet Machining Fiber Reinforced Polymer Composites

Predicting Surface Roughness and Delamination When Abrasive Waterjet Machining Fiber Reinforced Polymer Composites

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

Advances in Nano-finishing of Optical Glasses and Glass Ceramics

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