Conventional Abrasive Water Jet Research Articles

Investigation of gelatin enabled abrasive water slurry jet machining (AWSJM)

The paper presents the development of an analytical model and Computational Fluid Dynamics (CFD) model of abrasive water slurry jet machining (AWSJM), along with the experimental investigation of the micro-channel formation. The proposed work presents an improvised approach of AWSJM by equipping the conventional abrasive water jet (AWJ) machine with a setup for injecting polymer (Gelatin) solution into the AWJ nozzle, which leads to efficient energy transfer, improved cutting efficiency, and increased material removal rate. The CFD model is developed to simulate jet dynamic characteristics. The modeling of abrasive water jet machining (AWJM) and AWSJM process indicates that the calculated material removal rate is proportional to the power of the water jet. It is further proven from the analytical calculations that during the process of material removal, there is energy loss in both the AWJM and AWSJM. The results from the analytical model are validated through experiments performed on an AWJ machine. The micro-channels were fabricated to compare the depth of cut in the present research work. The analytical model developed to calculate the total depth of jet penetration correlates quite well with the experimental data. It is also observed that the maximum error predicted by the analytical expression and the simulation model for velocity and energy are within 10%.

Performance evaluation of the submerged abrasive water jet turning process for improving machinability of castamide

In this study, the submerged abrasive water jet turning (AWJT) system was used for improving machinability of castamide material and process parameters have been investigated comprehensively. Optimum parameters were determined as to minimize the surface roughness and maximize the material removal rate in the submerged turning process of castamide. 3-level traverse speed (TS), abrasive flow rate (AFR) and spindle speed (SS) were taken as the input parameters, and the experimental design was made as a full factorial design. The effect ratios of the input parameters were analyzed statistically by ANOVA and graphical methods, and their interactions were examined by 3D surface images. Optimum test condition was determined by TOPSIS and VIKOR methods. Experimental results were compared with conventional abrasive water jet process. In addition, regression equations were obtained for the explanation of the experimental results mathematically to show the relationships between the variables. According to the experimental results, submerged AWJT increased the surface roughness of castamide material by 15% compared to conventional AWJT and decreased the metal removal rate by 5.22%. ANOVA results showed that the traverse speed is the most effective parameter on the machinability of castamide. Traverse speed was found to be 83.11% effective on surface roughness and 85.56% on material removal rate. According to TOPSIS and VIKOR optimization results, 40 mm/min TS, 310 g /min AFR and 300 rpm SS values were determined as the optimum test conditions.

Some Technical Issues and Critical Assessment of Abrasive Water Jet Machining ( AWJM ) Process

This paper is focused on reviewing previously carried out work and written in literature. Non- conventional abrasive water jet technology is being utilized to machine variety of metals, their respective alloys and nonmetals. Mainly concentrated on Titanium alloys and difficulty in its machining. Numerous variables associated with the technology and their consequence on response variable were analyzed and summarized in this review. Paper conclude numerous gaps in research along with future scope.

Experimental Investigation on Cryogenic Assisted Abrasive Water Jet Machining of Aluminium Alloy

The purpose of the present investigation was to evaluate the abrasive water jet cutting performance by the application of a cryogenic liquid nitrogen jet in the cutting process. This technique was developed for improving the process capability of conventional abrasive water jet machining and enable a higher depth of cut and material removal rate, and better kerf profile and surface integrity. The experiments were conducted on AA5083-H32 aluminium alloy, using two different cutting methods, namely, abrasive water jet cutting and cryogenic assisted abrasive water jet cutting. Both cutting conditions were investigated by varying the water jet pressure, the abrasive mesh size and the abrasive water jet impact angle. Optical microscopy and Scanning Electron Microscope with Energy Dispersive X-ray Spectroscopy was used for studying the micro structure and morphology of the cut surfaces under both cutting conditions. There was an improvement in cutting performance features such as depth of penetration, material removal rate and kerf profile with the use of cryogenic assistance cutting approach. These results were produced due to the beneficial modification of erosion mechanism in the cutting zone as well as a reduction in particle embedment with the cut surface by about 56%.

Experimental investigations of gelatin-enabled abrasive water slurry jet machining

This work presents a description of abrasive water-slurry jet machining (AWSJM) to improve machining capabilities of conventional abrasive water jet machine. This work proposes a novel approach of AWSJM, where the conventional abrasive water jet machine (AWJM) is equipped with a liquid (gelatin) polymer solution injection system and a programmable control valve for controlling abrasive flow rate (AFR) and polymer solution flow rate. Parametric study of gelatin enabled AWSJM reveals the improvements in machining performance. Experimental investigations have been performed by varying concentration of the gelatin, pressure of water jet, abrasive flow rate, and abrasive size. The present work identifies the optimal range of process parameters for AWSJM, with natural gelatin as binder, with the response parameters being material removal rate, kerf width, and depth of cut. Gelatin produces a coherent, three-phase, four-content beam of higher kinetic energy in comparison with AWJ and results in increased material removal rate and depth of cut, with reduced kerf width.

High pressure abrasive slurry jet micro-machining using slurry entrainment

A novel high-pressure (water pump pressure up to 250 MPa) abrasive 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 (mixing tube diameter of 254 μm), premature erosion of system components was avoided. An optimum erosion rate of 2.7 mg/g was reached when machining Al6061-T6 with a slurry of 25 μm aluminum oxide particles under conditions (slurry flow rate = 200 g/min and water pump pressure = 235 MPa) near to those which theoretically maximized momentum transfer between the inlet slurry and the water jet entering the mixing chamber from the orifice. It was found that when the standoff distance increased tenfold, the erosion rate almost doubled in glass, but decreased by 50 % in Al6061-T6, due to differences in the erosion at the jet periphery for the two materials. For aspect ratios greater than 0.9, high-quality symmetric channels with a centerline waviness below 6.9 μm and a centerline roughness below 1.1 μm could be produced using a single pass at a low traverse velocity of 40 mm/min. The use of multiple machining passes at a relatively high traverse speed (~1000 mm/min) was found to produce asymmetric channels when the aspect ratio was greater than 0.9, owing to jet deflection from steps formed on the cutting front. Channels produced by micro-milling Al6061-T6 and glass had a 50 % lower centerline waviness and 16 % lower centerline roughness than those made with the conventional abrasive water jet in which air and abrasive entered the mixing chamber.

Experimental investigations of thermally enhanced abrasive water jet machining of hard-to-machine metals

This work explores thermally enhanced abrasive water jet machining (TEAWJM) process to improve the machining capabilities of conventional abrasive water jet machine by heating the work by an external heat source. The present work describes an experimental study of thermally enhanced machining (TEM) by adding an oxy acetylene gas welding setup as an external heat source to the machine setup which heats the work locally and temperature is measured by non-contact laser thermometer. The experimental data of cutting parameters at critical temperatures of hard-to-machine metals Inconel 718, Titanium (Ti6Al4V) and mild Steel (MS-A36) (ductile in nature) with full factorial DOE is presented here. Further, the effect of thermal treatment (during cutting) on surface morphology of the material machined has been studied for analyzing the effectiveness of the proposed methodology. Due to TEM, an increase in material removal rate, reduction in power consumption machining time is observed.

S0510103 アブレシブサスペンションジェットの水中切断特性

An abrasive suspension jet (ASJ) formed by propelling abrasive suspension through a nozzle has a greater cutting capability than the conventional abrasive water jet. However the cutting capability of submerged ASJs decreases drastically with increasing the standoff distance and the pressure around the jet. A sheathed nozzle with ventilation for ASJs has been developed as a mean of extending the effective stand-off distance and improving the cutting capabilities under submerged condition. In the present investigation, cutting tests by ASJs in air and under submerged condition are conducted with specimens of aluminum alloy. Air coated ASJs are formed by using a sheathed nozzle with ventilation. The relative cutting depth is defined as the cutting depth under submerged condition divided by the cutting depth in air at the same standoff distance. The relative cutting depth is arranged effectually by the cavitation number based on the cavity pressure measured at the sheath.

Acceleration of Abrasive Particles in Premixed Abrasive Water Jet Nozzle.

It has been shown that the premixed abrasive water jet system has a greater capacity for drilling and cutting than the conventional abrasive water jet system. In the present investigation, the motion of spherical particles in a premixed abrasive water jet nozzle is investigated theoretically. The flow in the nozzle is treated as one-dimensional flow. Convergent nozzles with and without a cylindrical focusing section are studied. The numerical results show that the particle velocity at the outlet of the nozzle has a tendency to increase in proportion to the square root of the injection pressure. The outlet particle velocity decreases with increasing diameter and specific gravity of the particles. The optimum length of the focusing section increases with increasing diameter and specific gravity of the particles.

Acceleration Characteristics of Abrasive Particles in Premixed Abrasive Water Jet Nozzle.

It has been shown that the premixed abrasive water jet system has a greater capacity for drilling and cutting than the conventional abrasive water jet system. In the present investigation, the motion of spherical particles in a premixed abrasive water jet nozzle is investigated theoretically. The flow in the nozzle is treated as one-dimensional flow. Convergent nozzles with and without a cylindrical focusing section are studied. The numerical results show that the particle velocity at the outlet of the nozzle has a tendency to increase in proportion to the square root of the injection pressure. The outlet particle velocity decreases with increasing diameter and specific gravity of the particles. The optimum length of the focusing section increases with increasing diameter and specific gravity of the particles.

Erosion due to Premixed Abrasive Water Jet under Submerged Condition.

It has been shown that the premixed abrasive water jet system, in which an abrasive suspension jet is formed by propelling a premixed abrasive suspension through a nozzle, has a greater capacity for drilling and cutting than the conventional abrasive water jet system. In the present investigation, an apparatus of the premixed abrasive water jet system was constructed for experimental purposes, and the erosion characteristics under submerged conditions were studied. The maximum jetting pressure was 20 MPa. The pressure in the test cell was varied up to 1 MPa. The erosion tests with the cavitating water jet and the submerged abrasive jet were conducted. It is found that the mass loss and the erosion pit depth when using the submerged abrasive jet decrease with increasing stand-off distance and pressure in the test cell. The erosion characteristics due to the submerged abrasive jet is affected greatly by the cavitation phenomenon.