scholarly journals Micro-channel milling using abrasive waterjets and high pressure abrasive slurry jets

2021 ◽  
Author(s):  
Naser Haghbin
Keyword(s):  
High Pressure ◽  
Particle Velocity ◽  
Flow Rate ◽  
Water Jet ◽  
Machining Process ◽  
Micro Milling ◽  
Micro Machining ◽  
Abrasive Water Jet ◽  
Micro Channels ◽  
Entrained Air

Abrasive water jet technology can be used for micro-milling using recently developed miniaturized nozzles. This thesis develops methodologies to predict the shape of micro-channels milled using high pressure abrasive water jets, and presents a new high pressure abrasive slurry jet micro-machining process. Since abrasive water jet (AWJ) machining is often used with both the nozzle tip and workpiece submerged in water to reduce noise and contain debris, the performance of submerged and unsubmerged abrasive water jet micro-milling of channels in 316L stainless steel and 6061-T6 aluminum at various nozzle angles and standoff distances were compared. It was found that the centerline erosion rate decreased with channel depth due to the spreading of the jet as the effective standoff distance increased, and because of the growing effect of the stagnation zone as the channel became deeper. The erosive jet spread over a larger effective footprint in air than in water, since particles on the jet periphery were slowed much more quickly in water due to increased drag. As a result, the width of a channel machined in air was wider than that in water. It was also found that the erosive efficacy distribution changed suddenly after the initial formation of the channel. Then, a new surface evolution model was developed that predicts the size and shape of relatively deep micro-channels up to aspect ratios of 3 resulting from unsubmerged and iv submerged abrasive water jet micro-machining (AWJM) using a novel approach in which two different erosive efficacy expressions were sequentially applied. Since the channels produced by AWJM were found to be relatively wavy due to fluctuations in abrasive mass flow rate, a novel high pressure (water pump pressure up to 345 MPa) abrasive jet slurry micro-machining (HASJM) system was introduced by feeding a premixed slurry into the mixing chamber of a water jet machine with a micro-nozzle. Moreover, an existing model developed for AWJM abrasive particle velocities was modified and used to predict the particle velocity in HASJM, and then verified using a double disc apparatus (DDA). The HASJM system was then used to study the effect of entrained air in abrasive water jet micro-machining (AWJM) by performing experiments at the same particle velocity and dose for the two systems. The centerline waviness, Wa, of micro-channels made in SS316L and Al60661-T6 using HASJM were typically 3.4 times lower than those made with AWJM using the same dose of particles due to the more constant abrasive flow rate provided by the HASJM provided. The centerline roughness, Ra was approximately the same in both processes at a traverse velocity of Vt=4572 mm/min and a nozzle angle of 90°. For micro-channels of a given depth, the widths of those made with HASJM were 25.6 % narrower than those produced with AWJM, mainly due to the wider jet that resulted from the entrained air in AWJM.

scholarly journals Micro-channel milling using abrasive waterjets and high pressure abrasive slurry jets

2021 ◽  
Author(s):  
Naser Haghbin
Keyword(s):  
High Pressure ◽  
Particle Velocity ◽  
Flow Rate ◽  
Water Jet ◽  
Machining Process ◽  
Micro Milling ◽  
Micro Machining ◽  
Abrasive Water Jet ◽  
Micro Channels ◽  
Entrained Air

Abrasive water jet technology can be used for micro-milling using recently developed miniaturized nozzles. This thesis develops methodologies to predict the shape of micro-channels milled using high pressure abrasive water jets, and presents a new high pressure abrasive slurry jet micro-machining process. Since abrasive water jet (AWJ) machining is often used with both the nozzle tip and workpiece submerged in water to reduce noise and contain debris, the performance of submerged and unsubmerged abrasive water jet micro-milling of channels in 316L stainless steel and 6061-T6 aluminum at various nozzle angles and standoff distances were compared. It was found that the centerline erosion rate decreased with channel depth due to the spreading of the jet as the effective standoff distance increased, and because of the growing effect of the stagnation zone as the channel became deeper. The erosive jet spread over a larger effective footprint in air than in water, since particles on the jet periphery were slowed much more quickly in water due to increased drag. As a result, the width of a channel machined in air was wider than that in water. It was also found that the erosive efficacy distribution changed suddenly after the initial formation of the channel. Then, a new surface evolution model was developed that predicts the size and shape of relatively deep micro-channels up to aspect ratios of 3 resulting from unsubmerged and iv submerged abrasive water jet micro-machining (AWJM) using a novel approach in which two different erosive efficacy expressions were sequentially applied. Since the channels produced by AWJM were found to be relatively wavy due to fluctuations in abrasive mass flow rate, a novel high pressure (water pump pressure up to 345 MPa) abrasive jet slurry micro-machining (HASJM) system was introduced by feeding a premixed slurry into the mixing chamber of a water jet machine with a micro-nozzle. Moreover, an existing model developed for AWJM abrasive particle velocities was modified and used to predict the particle velocity in HASJM, and then verified using a double disc apparatus (DDA). The HASJM system was then used to study the effect of entrained air in abrasive water jet micro-machining (AWJM) by performing experiments at the same particle velocity and dose for the two systems. The centerline waviness, Wa, of micro-channels made in SS316L and Al60661-T6 using HASJM were typically 3.4 times lower than those made with AWJM using the same dose of particles due to the more constant abrasive flow rate provided by the HASJM provided. The centerline roughness, Ra was approximately the same in both processes at a traverse velocity of Vt=4572 mm/min and a nozzle angle of 90°. For micro-channels of a given depth, the widths of those made with HASJM were 25.6 % narrower than those produced with AWJM, mainly due to the wider jet that resulted from the entrained air in AWJM.

An Experimental Study of the Abrasive Water Jet Micro-Machining Process for Quartz Crystals

2012 ◽  
Vol 565 ◽  
pp. 339-344 ◽  
Author(s):  
H. Qi ◽  
J.M. Fan ◽  
Jun Wang
Keyword(s):  
Experimental Study ◽  
Removal Rate ◽  
Water Jet ◽  
Machining Process ◽  
Bottom Surface ◽  
Micro Machining ◽  
Abrasive Water Jet ◽  
Process Variables ◽  
Jet Impact ◽  
Micro Channels

An experimental study of the machining process for micro-channels on a brittle quartz crystal material by an abrasive slurry jet (ASJ) is presented. A statistical experiment design considering the major process variables is conducted, and the machined surface morphology and channelling performance are analysed to understand the micro-machining process. It is found that a good channel top edge appearance and bottom surface quality without wavy patterns can be achieved by employing relatively small particles at shallow jet impact angles. The major channel performance measures, i.e. material removal rate (MRR) and channel depth, are then discussed with respect to the process parameters. It shows that with a proper control of the process variables, the abrasive water jet (AWJ) technology can be used for the micro-machining of brittle materials with high quality and productivity.

Effect of entrained air in abrasive water jet micro-machining: Reduction of channel width and waviness using slurry entrainment

Wear ◽  
2015 ◽  
Vol 344-345 ◽  
pp. 99-109 ◽  
Author(s):  
Naser Haghbin ◽  
Farbod Ahmadzadeh ◽  
Jan K. Spelt ◽  
Marcello Papini
Keyword(s):  
Water Jet ◽  
Channel Width ◽  
Micro Machining ◽  
Abrasive Water Jet ◽  
Entrained Air

Miniaturization of injection abrasive water jet machining process

2006 ◽  
Vol 220 (11) ◽  
pp. 1697-1705 ◽  
Author(s):  
H Orbanic ◽  
B Jurisevic ◽  
D Kramar ◽  
M Grah ◽  
M Junkar
Keyword(s):  
Water Jet ◽  
Heat Sinks ◽  
Machining Process ◽  
Process Efficiency ◽  
Abrasive Water Jet ◽  
Element Analysis ◽  
Abrasive Particles ◽  
Cutting Head ◽  
Simulation Based ◽  
Awj Cutting

This contribution presents the possibilities of applying abrasive water jet (AWJ) technology for multi-material micromanufacture. The working principles of injection and suspension AWJ systems are presented. Characteristics of this technology, such as the ability to machine virtually any kind of material and the absence of a relevant heat-affected zone, are given, especially those from which the production of microcomponents can benefit. A few attempts to miniaturize the AWJ machining process are described in the state-of-the-art preview. In order to develop and improve the AWJ as a microtool, a numerical simulation based on the finite element analysis is introduced to evaluate the effect of the size abrasive particles and the process efficiency of microsized AWJ. An ongoing project in which an improved mini AWJ cutting head is being developed, is presented. Finally, the possible fields of application are given, including a case study on the machining of miniaturized heat sinks.

scholarly journals Permeability Enhancement Properties of High-Pressure Abrasive Water Jet Flushing and Its Application in a Soft Coal Seam

2021 ◽  
Vol 9 ◽  
Author(s):  
Xinzhe Zhang ◽  
Piotr Wiśniewski ◽  
Sławomir Dykas ◽  
Guojie Zhang
Keyword(s):  
High Pressure ◽  
Coal Seam ◽  
Water Jet ◽  
Gas Pressure ◽  
Theory And Practice ◽  
Abrasive Water Jet ◽  
Gas Drainage ◽  
Permeability Enhancement ◽  
Soft Coal ◽  
Soft Coal Seam

High-pressure abrasive water jet flushing (HPAWJF) is an effective method used to improve coal seam permeability. In this study, based on the theories of gas flow and coal deformation, a coupled gas-rock model is established to investigate realistic failure processes by introducing equations for the evolution of mesoscopic element damage along with coal mass deformation. Numerical simulation of the failure and pressure relief processes is carried out under different coal seam permeability and flushing length conditions. Distributions of the seepage and gas pressure fields of the realistic failure process are analyzed. The effects of flushing permeability enhancement in a soft coal seam on the gas drainage from boreholes are revealed by conducting a field experiment. Conclusions can be extracted that the gas pressure of the slotted soft coal seam is reduced and that the gas drainage volume is three times higher than that of a conventional borehole. Field tests demonstrate that the gas drainage effect of the soft coal seam is significantly improved and that tunneling speed is nearly doubled. The results obtained from this study can provide guidance to gas drainage in soft coal seams regarding the theory and practice application of the HPAWJF method.

Basis of Novel Technique for Spatial Objects Shaping With High-Pressure Abrasive Water Jet

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
P. J. Borkowski ◽  
J. A. Borkowski
Keyword(s):  
High Pressure ◽  
Feed Rate ◽  
Spatial Model ◽  
Theoretical Basis ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Spatial Objects ◽  
Novel Technique ◽  
Raster Image ◽  
Novel Method

Novel method for the 3D shaping of different materials using a high-pressure abrasive water jet is presented in the paper. For the steering movement process of the jet, a principle similar to the raster image way of record and readout was used. However, respective colors of pixels of such a bitmap are connected with adequate jet feed rate that causes erosion of material with adequate depth. Thanks to that innovation, one can observe spatial imaging of the object. Theoretical basis as well as spatial model of material shaping including steering program is presented in. There are also presented experimental erosion results as well as practical examples of the object’s bas-relief made of metal.

COMPUTATIONAL FLUID DYNAMICS SIMULATION OF EROSION-CORROSION IN ABRASIVE WATER JET MACHINING

2021 ◽  
pp. 2150031
Author(s):  
H. DENİZ ADA ◽  
MEHMET ERDEM ◽  
KADİR GOK
Keyword(s):  
High Pressure ◽  
Water Jet ◽  
Dynamics Simulation ◽  
Abrasive Water Jet ◽  
Manufacturing Method ◽  
Water Jet Cutting ◽  
Erosion Corrosion ◽  
Computer Environment ◽  
Manufacturing Methods ◽  
Traditional Manufacturing

Today, conventional machining with chip or machining without chip machining manufacturing methods is used to bring to the desired dimensions sizes the machines and equipment used in the industry. However, non-traditional manufacturing methods are used in cases where traditional machining manufacturing methods are inadequate. Cutting with water jet which is one of the non-traditional manufacturing methods is commonly used in several fields of industry. Unlike traditional manufacturing methods such as turning and milling, not using of a physical cutting tool is among the advantages of the method. Abrasive water jet manufacturing method was started to be applied by adding abrasive particles in the water jet. Apart from the superior properties of the method, possible damages occur in the water jet nozzle due to processes such as cutting or drilling by applying high pressure. Erosion-corrosion is the leading damage among these damages. In this study, the erosion-corrosion in the nozzle caused by high-pressure water and abrasive during the abrasive water jet cutting process was simulated in the computer environment. In this paper, the erosion rate in the nozzle was calculated as 6,90E-06[Formula: see text]kg/m2[Formula: see text]s. This value was converted as 0,30[Formula: see text]mm (27,09[Formula: see text]mm for yearly) via developed software for 100[Formula: see text]h.

Sustainable Solution to Low-Cost Alternative Abrasive From Electric Ceramic Insulator Waste For Use in Abrasive Water Jet Machining

2021 ◽  
Author(s):  
Sabarinathan Palaniyappan ◽  
Annamalai Veiravan ◽  
Rajkumar Kaliyamoorthy ◽  
Vishal Kumar
Keyword(s):  
Performance Indicators ◽  
Value Added ◽  
Water Jet ◽  
Raw Material ◽  
Machining Process ◽  
Abrasive Water Jet ◽  
Machining Performance ◽  
Electric Insulator ◽  
Abrasive Water Jet Machining ◽  
Ceramic Insulator

Abstract Increasing demand and resource overuse has prompted the exploration of spent secondary materials as a primary raw material for a variety of applications, leading to a more sustainable environment. Spent electric grid ceramic insulator, one of the waste materials of ceramic industry has a good hardness and strength. It can be reused as value added material in Abrasive Water Jet Machining (AWJM) industry. This present work deals with conversion of electric insulator rejects (EIR) into a cost-effective replacement material for abrasive water jet machining process. Mechanical crushing method is opted to generate the abrasive grit for the machining process. Grit generation pattern and the friability of the electric insulator rejects were determined experimentally. The results indicate that the friability of the processed electric insulator rejects is comparable with the commercially available garnet abrasive. Geometric parameters such as sphericity, elongation ratio, and shape factor for the processed electric insulator rejects were studied using scanning electron microscopy. The machining performance indicators for standard aluminium material such as volume of material removal, kerf angle, surface roughness and cutting width were measured for electric insulator rejects and compared with existing garnet abrasive grain. The experimental results of newly generated electric insulator reject abrasive were matched with performance indicators of the garnet abrasive. The observed deviation was lower proving that it can be used as alternative abrasive in the abrasive jet machining process. Cost analysis and recycling ability predict the economical usability of the newly generated abrasives.

scholarly journals A numerical and experimental study of oblique impact of ultra-high pressure abrasive water jet

2016 ◽  
Vol 8 (3) ◽  
pp. 168781401663679 ◽  
Author(s):  
Can Kang ◽  
Haixia Liu ◽  
Xiuge Li ◽  
Ya Zhou ◽  
Xiaonong Cheng
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Oblique Impact ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Ultra High Pressure
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