Papers by Keyword: Abrasive Water Jet Machining

Abstract: A composite is a solid material created by combining two or more different substances, each with its own set of qualities, to create a new substance with properties that outperform the original components for a specific use. Currently composite materials are widely applied across various fields due to its superior properties. The fibre reinforced composites being light in weight, and high strength are replacing metals in many applications. Nowadays, more focus is paid in developing sustainable and environment friendly materials without compromise in the quality. This reason led to the development of Natural Fibre Reinforced Composite (NFRC) materials, which is gaining more attention towards them. Though many NFRCs were developed, machining is a very big challenge. Compared to the traditional machining processes, the non-traditional machining process is proved to be recommendable for machining NFRC materials. In this article, the numerous research endeavors carried out in machining of NFRCs using Abrasive Water Jet Machining (AWJM) process is reviewed. This article describes the different parameters considered in AWJM process and their influence over the machining characteristics of NFRCs. Based on the different research carried out, the use of nanofillers in the right composition is expected to increase the performance of the AWJM process over NFRCs.

Abstract: Now a days, Non-Conventional Machining process is gaining more attention by the researchers. Abrasive Water jet machining (AWJM) is one of such machining process where material is removed with abrasive slurry as cutting tool. The present work discuss about the development of an optimal solution for minimizing surface roughness using a response surface methodology (RSM) while machining of EN grade steel. The machining parameters considered for the study are Abrasive Grain Size (AGS) and Hydraulic Pressure (HP) and Stand Off Distance (SOD) and the Abrasive Flow Rate (AFR). The response parameter is surface roughness (Ra). The experiments are performed based on the Box-Behnken design. Additionally, the significance of the developed optimization design has been identified using analysis of variance (ANOVA). Finally, the validity and adequacy of the developed model are done through confirmation tests. Key Words: Abrasive Water jet Machining, Response Surface Methodology, Optimization, ANOVA

Abstract: Abrasive water jet machining is a process that removes material using sand and water. This versatile process uses a high-pressure water jet loaded with abrasive particles of mineral origin. It allows the machining of all materials and is particularly suitable for machining or stripping applications on hard metal sheets. Due to a local action, the abrasive water jet limits heating and deformation. During machining, the removal of material occurs abrasion and erosion [1]. The identification of the respective importance of this abrasion and this erosion conditions the precision of the modeling of the machined depth. In this study, these mechanisms are presented and characterized for machining on 6mm thickness TiAl6V titanium alloys sheets with or without inclination of the jet. It is possible to model an elementary passage and it allows predicting the pocket bottom profile obtained after a succession of passages. During machining, two mechanisms appear. Abrasion occurs when machining an elementary pass. Erosion will characterize the effect of repetition of passages. The analysis of the machined profiles makes it possible to characterize the influence of the abrasion mechanism and abrasion mechanism. The variation of the coefficients associated with these mechanisms can be characterized as a function of the angle of inclination of the jet.Keywords: Abrasive water jet machining, Material removal mechanism, Abrasion, Erosion, Titanium alloy, Abrasive particles

Abstract: This paper explains and demonstrates how miniature gears of excellent surface quality can be manufactured by modern machining methods. Necessity of gear finishing by post processes such as grinding, lapping, honing etc. is the major limitation of all conventional methods of miniature gear manufacturing. To overcome this limitation, modern machining methods such as wire-EDM, abrasive waterjet machining, and laser beam machining etc. have been explored. It resulted in significant achievements in geometric accuracy, surface finish, and integrity of miniature gears. Using modern machining methods, it is possible to manufacture gears equipped with precision finish (average roughness 1 μm), high geometric accuracy (DIN quality 5), and defect-free tooth surfaces at significantly low cost. This paper aims to facilitate researchers by providing information on important aspects as regards to the manufacturing of miniature gears by modern machining methods and hopes research and development in this area to establish the field further.

Abstract: In order to increase the cutting and breaking capacity of abrasive water jet machining (AWJM), abrasive particles are usually added to water. The AWJM technology is generally used for harder and heavier machinable materials like thick sheets, composite materials with metal and ceramic properties and others within these categories to just cite a few. The contribution is mainly focused on the analysis of the surface properties of the steel S235 after the cutting process, and this depending on the cutting speed of the water jet. Three different cutting speeds were used for the analysis because this cutting parameter significantly affects the resulting quality of the machined surface. A contact profile method was used to analyze surface roughness. The observed surface roughness parameters were the Ra, Rt and Rz respectively. The above-mentioned surface roughness parameters were measured in three positions, i.e.: at the inlet, middle and exit positions of the water jet with respect to the machined material.

Abstract: Experiments were carried out in Inconel 718 in order to investigate the effect of abrasive water-jet process variables on surface and subsurface condition. A Design of Experiments (DoE) approach was taken, considering variables such as water pressure, traverse rate, abrasive mass flow rate and abrasive grit size. The experimental variables were related to taper ratio, surface roughness of different zones in the machined surface and subsurface condition (deformation and crater depth). Statistical analysis was carried out in order to develop mathematical models which include process variable interactions and quadratic terms. This led to models with high correlation and prediction power which allow a better understanding of the process and can form the base for further process optimisation. The models were validated with additional experiments and showed good agreement with the water jet system. The results showed that water pressure has a nonlinear behaviour in the quality of the surface and sub-surfaces and that interaction between the variables had a significant effect on the quality of the surfaces and sub-surfaces generated by the AWJ.

Abstract: The use of fiber reinforced polymer (FRP) composites in the aircraft and automotive industries exponentially. Reinforced fibers which are abrasive in nature make it hard to machine by the traditional machining. Dissipation of heat into workpiece which in turn results in enhanced cutting tool wear and damage to the workpiece is the common problems faced in traditional machining of FRPs. Nontraditional machining is favorable to reduce these issues. Abrasive waterjet machining (AWJM) is one of the best choices for machining FRPs. Development in AWJM of FRPs and the current research in this field will be discussed in details. Machining process of FRPs, quality dependents such as surface finish and variable cutting parameters will be addressed. One of main issues in AWJM noise due to high flow rate of water jet will be addressed. The importance of human safety aspects when AWJM is employed will be highlighted. Limitations and challenges in AWJM are presented elaborately.

Abstract: This Abrasive Water Jet Machining (AWJM) process is usually used to through cut materials which are difficult to cut by conventional machining processes. This process may also be used for controlled depth milling (CDM) of materials. This work primarily focuses on controlling the abrasive flow rate to reduce the time for machining the component. Here, an experimental setup is made with a modified attachment for abrasive feed system to machine for Ti-6Al-4V alloy. The work also investigates the surface morphology, tolerance on depth of machining and surface waviness for the modified setup. With change in mass flow rate of abrasive, the traverse speed is altered and its effects on the machining time are studied. It is observed that traverse speed is an important parameter in the case of CDM for AWJM. It is also shown that surface waviness can be reduced as traverse speed is increased by using modified abrasive feeding system.

Abstract: This Abrasive Water Jet Machining (AWJM) process is usually used to cut the materials which are difficult to cut by conventional machining processes. In this work, controlled depth milling (CDM) is done using AWJM. This work primarily focuses on controlling the abrasive flow rate to reduce the time for machining the component. Here, an experimental setup is made with a modified attachment for abrasive feed system to machine stainless steel. The work also investigates the surface morphology, tolerance on depth of machining and surface waviness for the modified setup. With change in mass flow rate of abrasive, the traverse speed may also be altered and its effects on the machining time are controlled. This work also employs Non-destructive Testing (NDT) method i.e. ultrasonic flaw detector to find out internal defects and cracks in the milled material.

Abstract: The experiments on dicing monocrystalline silicon wafer using micro abrasive water jet turning were performed. A specifically designed water jet machine tool with four axes was developed and a specially designed cutting head has developed, in which the inside diameter of orifice and focusing tube is f125 mm and f500 mm respectively, while the silicon carbide solid abrasives with average diameter of 25-100 mm was used. In order to control the flow rate of micro abrasives precisely, an abrasive feed system with auger mechanism driven by DC motor reducer was used. The diameters of monocrystalline silicon bars are around 50 mm. Two basic turning methods, i.e. turning with stationary jet and turning with moving jet were applied. The preliminary experimental results such as kerf width, wafer thickness, surface quality etc. were analyzed. It was found that micro abrasive water jet can be used to precisely turn brittle materials like monocrystalline silicon. The turned wafer with thickness of 1 mm above could be achieved. A thinner wafer less than 1 mm is difficult to obtain during experiments because of cracking or chipping. Experiments demonstrate that the wafer surface has macro stripping characteristics similar to linear cutting. It was observed that there is less waviness and smooth surface on the turned wafer when with moving jet. And it depends greatly on the water jet pressure, feed rate of the jet, rotation speed of silicon bar, abrasive particle size as well as flow rate of abrasive. The detailed analysis indicates that the surface roughness of turned wafer with moving jet is around R_a 1.5-5.6 μm, while that of turned wafer with stationary jet is around R_a6.3 μm, when other conditions are same. The results show that surface quality turning with moving jet is obviously better than that of stationary jet. Smaller surface roughness of turned wafer could be obtained when finer abrasive is used. The experiment shows also that the wafer is typically tapered with either the stationary jet or moving jet. There is a concave on the turned surface when feed rate of the jet is too low or dwell time is too long. This is attributed to the jet rebound from one face to the other. Therefore there is an optimizing rotational speed during turning. This study indicates that dicing mono crystalline silicon wafer using micro abrasive water jet turning has potential application in semiconductor industry.