Improving Milling Performance with High Pressure Waterjet Assisted Cooling / Lubrication

1995 ◽  
Vol 117 (3) ◽  
pp. 331-339 ◽  
Author(s):  
R. Kovacevic ◽  
C. Cherukuthota ◽  
R. Mohan

During machining, due to relative motion between tool and workpiece, severe thermal/frictional conditions exist at the tool-chip interface. Metal machining processes can be more efficient in terms of increasing the metal removal rate and lengthening tool life, if the thermal/frictional conditions are controlled effectively. A high pressure waterjet assisted coolant/lubricant system that can be used in conjunction with rotary tools (e.g., face milling) is developed here. The performance of this system is evaluated in terms of cutting force, surface quality, tool wear, and chip shape. The improvement in the effectiveness of the developed system with increase in water pressure and orifice diameter is also investigated. Stochastic modeling of the surface profile is performed to obtain more information about the role of waterjet in the machining process.

Author(s):  
M. A. Deore ◽  
R. S Shelke

The manufacturing process of surface grinding has been established in the mass production of slim, rotationally symmetrical components. Due to the complex set-up, which results from the large sensitivity of this grinding process to a multiplicity of geometrical, kinematical and dynamical influence parameters, surface grinding is rarely applied within limited-lot production. The substantial characteristics of this grinding process are the simultaneous guidance and machining of the work piece on its periphery. Surface grinding is an essential process for final machining of components requiring smooth surfaces and precise tolerances. As compared with other machining processes, grinding is costly operation that should be utilized under optimal conditions. Although widely used in industry, grinding remains perhaps the least understood of all machining processes. The proposed work takes the following input processes parameters namely Work speed, feed rate and depth of cut. The main objective of this work is to predict the grinding behavior and achieve optimal operating processes parameters. a software package may be utilized which integrates these various models to simulate what happens during surface grinding processes. predictions from this simulation will be further analyzed by calibration with actual data. It involves several variables such as depth of cut, work speed, feed rate, chemical composition of work piece, etc. The main objective in any machining process is to maximize the Metal Removal Rate (MRR) and to minimize the surface roughness (Ra). In order to optimize these values Taguchi method, ANOVA and regression analysis is used.


Author(s):  
S. Chakraborty ◽  
S. Mitra ◽  
D. Bose

The recent scenario of modern manufacturing is tremendously improved in the sense of precision machining and abstaining from environmental pollution and hazard issues. In the present work, Ti6Al4V is machined through wire EDM (WEDM) process with powder mixed dielectric and analyzed the influence of input parameters and inherent hazard issues. WEDM has different parameters such as peak current, pulse on time, pulse off time, gap voltage, wire speed, wire tension and so on, as well as dielectrics with powder mixed. These are playing an essential role in WEDM performances to improve the process efficiency by developing the surface texture, microhardness, and metal removal rate. Even though the parameter’s influencing, the study of environmental effect in the WEDM process is very essential during the machining process due to the high emission of toxic vapour by the high discharge energy. In the present study, three different dielectric fluids were used, including deionised water, kerosene, and surfactant added deionised water and analysed the data by taking one factor at a time (OFAT) approach. From this study, it is established that dielectric types and powder significantly improve performances with proper set of machining parameters and find out the risk factor associated with the PMWEDM process.


Author(s):  
Sagil James ◽  
Sharadkumar Kakadiya

Shape Memory Alloys are smart materials that tend to remember and return to its original shape when subjected to deformation. These materials find numerous applications in robotics, automotive and biomedical industries. Micromachining of SMAs is often a considerable challenge using conventional machining processes. Micro-Electrical Discharge Machining is a combination of thermal and electrical processes, which can machine any electrically conductive material at micron scale independent of its hardness. It employs dielectric medium such as hydrocarbon oils, deionized water, and kerosene. Using liquid dielectrics has adverse effects on the machined surface causing cracking, white layer deposition, and irregular surface finish. These limitations can be minimized by using a dry dielectric medium such as air or nitrogen gas. This research involves the experimental study of micromachining of Shape Memory Alloys using dry Micro-Electrical Discharge Machining process. The study considers the effect of critical process parameters including discharge voltage and discharge current on the material removal rate and the tool wear rate. A comparison study is performed between the Micro-Electrical Discharge Machining process with using the liquid as well as air as the dielectric medium. In this study, microcavities are successfully machined on shape memory alloys using dry Micro-Electrical Discharge Machining process. The study found that the dry Micro-Electrical Discharge Machining produces a comparatively better surface finish, has lower tool wear and lesser material removal rate compared to the process using the liquid as the dielectric medium. The results of this research could extend the industrial applications of Micro Electrical Discharge Machining processes.


Author(s):  
Greg Pasken ◽  
J. Ma ◽  
Muhammad P. Jahan ◽  
Shuting Lei

Abstract The most common problem when machining titanium using traditional metal cutting processes is that tools rapidly wear out and need to be replaced. This study examines the ability of a pure water jet to machine Ti-6Al-4V via simulations using ABAQUS’s Smoothed Particle Hydrodynamics (SPH). These simulations are then validated experimentally at two pressures, 138 MPa and 317 MPa. Using a Maxiem water jet built by Omax, experiments are conducted by creating a series of 5 lines that are 5 inches (127 mm) long placed 0.5 inches (12.7 mm) apart on a 1 mm thick Ti-6Al-4V workpiece. Predictive modeling is also conducted using the two additional pressures 400 MPa and 621 MPa as well as three orifice diameters 0.254 mm, 0.3556 mm, and 0.4572 mm. The simulations are validated at both pressures and had a percent error less than 2.6% which were within the standard deviation of the experimental results. The predictive modeling indicates that the pressures above 317 MPa create a near identical percent increase from the orifice diameter but the kerf has a more noticeable decrease in width of cut as the pressure increases. The 138 MPa has the smoothest surface profile compared to the other pressures. The volume of removed material decreases as the pressure increases but the material removal rate (MRR) increases as the pressure increases. This is due to the velocity of the water increasing as the pressure increases causing a lower run time. The 621 MPa is the best pressure to machine Ti-6Al-4V as it has a better MRR than the other pressures used in the predictive modelling.


2016 ◽  
Vol 836-837 ◽  
pp. 161-167
Author(s):  
Anna Thouvenin ◽  
Xin Li ◽  
Ning He ◽  
Liang Li

High speed milling is one of the most commonly used machining processes in many fields of the industry. It is regarded as a simple and fast solution to achieve a high material removal rate, which allows an important production of parts. Unbalance is a problem in any machining process but becomes a considerable problem when reaching high speed machining. The vibrations due to an unbalanced tool or tool holder can result in a poor surface quality and a damaged tool. The damping of the vibrations can be achieved with a specially designed tool showing an anti-vibration clearance angle. This paper shows the influence of the anti-vibration clearance angle by a computational model and a set of experiments to see if it can reduce or suppress the vibrations due to unbalance in high speed milling.


2011 ◽  
Vol 496 ◽  
pp. 205-210 ◽  
Author(s):  
János Kundrák ◽  
Gyula Varga

Abstract. The development of metal machining processes and procedures has been characterized by aiming at accuracy and economy for decades. The applied coolants and lubricants helped this process; however, they are polluting the environment. For today that is a social demand and technical possibility that environmental aspects should predominate better in production engineering. In the frame of this article, through the application of dry hard turning we shall spotlight on its economy and efficiency. We shall prove that, keeping the same accuracy and economic efficiency, it is possible to choose a machining process by which the environmental load can be reduced compared to the most frequently applied grinding.


2013 ◽  
Vol 394 ◽  
pp. 205-210
Author(s):  
A.K.M. Nurul Amin ◽  
Fawaz Mohsen Abdullah ◽  
Ummu Atiqah Khairiyah B. Mohammad ◽  
Muammer Din Arif

Chatter is a self-excited and violent form of vibration which is almost unavoidable in all machining processes. It affects surface roughness, machining accuracy, cutting tool and machine tool life, metal removal rate; and consequently operation cost. This research work focuses on investigation of the influence of the cutting parameters on chatter and implementation of a method based on application of permanent magnet for controlling chatter during turning of stainless steel AISI 304 using coated carbide tool. For this purpose, a powerful permanent bar magnet (of strength 1250-1350 Gauss) was placed inside a specially developed fixture mounted on the lathe machine carriage, to apply magnetic field to the base of the tool holder in the Z direction. The effectiveness of the application of the magnet on chatter suppression was measured in terms of reduction of amplitude of chatter compared to conventional turning. To achieve this, a small central composite design (CCD) of the Response Surface Methodology (RSM) with five levels and an alpha value of 1.4142, was used in the design of the experiments (DoE). Design-Expert 6.0 software was utilized in the model development process. Vibration monitoring was done using an online vibration monitoring system. FFT analysis of the recorded vibration signals was conducted using DASYLab software to evaluate the peak chatter amplitudes and their corresponding excited frequencies. The acceleration amplitude was found to be reduced by a maximum of 73.43% and an average of 31.58% due to the effect of damping on the resonant amplitude offered by the magnetic field created by the permanent magnet.


Author(s):  
Pankaj Kumar Shrivastava ◽  
Shrihar Pandey ◽  
Shivam Dangi

Electrical arc machining is the thermal energy-based unconventional machining process, which utilizes energy of arc to melt and vaporize workpiece material. Electrical arc machining has the capability to machine advanced materials such as metal matrix composites, superalloys, and conductive ceramics effectively. The process is considered to be efficient than most of the other unconventional machining processes in terms of the material removal rate. But it has got limitations because it results in a very poor surface finish. Tool wear rate, recast layer formation, surface and subsurface cracks, and geometrical inaccuracy are other limitations up to a certain extent. In this paper, the comprehensive review of research carried out so for in the area of electrical arc machining has been presented. The paper discusses the detailed experimental and theoretical studies done on electrical arc machining to elucidate the effects of various input control factors on different quality characteristics. The paper also contains modeling and optimization studies done so far in electrical arc machining and finally discusses the future research possibilities in the area.


Author(s):  
Navriti Gupta ◽  
◽  
A.K Agrawal, ◽  
R.S Walia ◽  
Ranganath Singari

D2 steel is an industrial tool steel. It is widely used in the tool and die industry for making cutting tool inserts, bending inserts, restriking inserts, etc. which can be taken out after their tool life. D2 steel is a very tough steel and difficult to machine also. High generations tool bits like Tungsten carbides and Titanium carbides are required to machine them. The heat treatment follows the machining process. Their machinability is very low. CNC machines are often used to finish them. Often they are machined using programs on UG-NX Uni Graphics(CAM) and DELCAM. And they have to be machined in three steps. Roughing operations, followed by Semi-Finish machining and the last step is finish machining.CNC machining centers are versatile in their applications in metal removal processes. Often they are so modernized that just like many manufacturing operations, metal removal can be automated too. The need for CNC machining arises due to extensive finishing requirements in the aerospace, automotive industries. However, the CNC or Computer and Numerically controlled machining process usage is not limited to these industries only. Tool and Die industry also is heavily dependent on CNC material removal and machining processes as now replaceable inserts are widely used in this industry.


NANO ◽  
2011 ◽  
Vol 06 (06) ◽  
pp. 561-568 ◽  
Author(s):  
G. TAHMASEBIPOUR ◽  
Y. TAHMASEBIPOUR ◽  
M. GHOREISHI

Electrical discharge machining (EDM) process is one of the advanced machining processes that can machine the various complex shapes from all conductor and semiconductor materials. Wide and diverse applications of Micro-EDM process in microfabrication and micro- to nano-miniaturization tendency is promising application of Nano-EDM process in nanofabrication. The Nano-EDM is a precise, sensitive and costly process. Therefore, simulation of nanocrater produced by each spark in this process prevents spending extra time and cost to perform Nano-EDM process through trial and error method. In this paper nanocrater machined by the Nano-EDM process on a gold nanofilm is simulated under practically experimental conditions. Radius, depth and volume of the nanocrater are evaluated versus process conditions (average power and pulse duration) and workpiece thickness (50 nm, 100 nm and 300 nm). It is observed that radius of the nanocrater is increased exponentially with increasing spark pulse duration. Also, depth, volume of the removed material from the workpiece surface and material removal rate (MRR) are increased with increasing consumed energy by each spark. By increasing thickness of the nanofilm, volume of the removed material and dimensions of the nanocrater are decreased.


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