3D Finite Element Assisted Numerical Simulation of Orbital Drilling Process of Ti6Al4V

Author(s):  
Salman Pervaiz ◽  
Ali Daneji ◽  
Sathish Kannan

Abstract Drilling is one of most executed manufacturing operations to assist the assembling of different engineering components. In orbital drilling process, a milling tool is rotating along its own axis in combination with the spiral rotational movement. The rotation of tool about its own axis is with high rotational speed, but the spiral movement of tool is at low rotational speed. These rotational movements generate a hollow geometry when moved in combination. Orbital drilling process is emerging as a viable drilling process when burr formation has to be reduced from the metallic workpiece. It is gaining more popularity in the aerospace industry due to its ability to machine holes in difficult to cut alloys, composites and composite stacks. Major advantages of orbital drilling are linked with efficient chip evacuation, reduction in heat build-up and low thrust forces due to its intermittent cutting nature. The cutting forces generated during the process can be taken as a significant output parameter that play a vital role towards the overall performance of the cutting process. Controlling the cutting forces under threshold value can improve the overall machining efficiency by limiting associated deflections, tool wear and energy consumption. The current paper aims to study the orbital drilling process using finite element (FE) assisted numerical methodology. The study will utilize different orbital drilling parameters such as spindle speed, orbit speed and axial feed rate, and explore their influence on the over all machining process.

2011 ◽  
Vol 70 ◽  
pp. 315-320 ◽  
Author(s):  
Riaz Muhammad ◽  
Agostino Maurotto ◽  
Anish Roy ◽  
Vadim V. Silberschmidt

Analysis of the cutting process in machining of advanced alloys, which are typically difficult-to-machine materials, is a challenge that needs to be addressed. In a machining operation, cutting forces causes severe deformations in the proximity of the cutting edge, producing high stresses, strain, strain-rates and temperatures in the workpiece that ultimately affect the quality of the machined surface. In the present work, cutting forces generated in a vibro-impact and hot vibro-impact machining process of Ti-based alloy, using an in-house Ultrasonically Assisted Turning (UAT) setup, are studied. A three-dimensional, thermo-mechanically coupled, finite element model was developed to study the thermal and mechanical processes in the cutting zone for the various machining processes. Several advantages of ultrasonically assisted turning and hot ultrasonically assisted turning are demonstrated when compared to conventional turning.


Author(s):  
A. Sadek ◽  
A. O. Nassef ◽  
M. Meshreki ◽  
M. H. Attia

Defects associated with drilling of Carbon Fiber-Reinforced Polymers (CFRPs) are of major economic and safety concerns for aerospace manufacturers. One of the most critical defects associated with drilling of CFRP laminates is delamination of layers which can be avoided by keeping the drilling forces below some threshold levels. Orbital Drilling (OD) is an emerging drilling process that exhibits lower cutting forces and temperatures, easier chip removal, higher produced surface quality, longer tool life, and a high possibility for dry machining. The OD process is featured by cyclic engagement and disengagement between the tool and the workpiece whereby a considerable part of the work done by the tool is directed towards the tangential direction while the work done in the axial direction is reduced. This reduces the risk of delamination at the exit. The objective of this research work is to investigate the effect of the OD process key parameters with respect to the produced hole attributes (surface roughness, delamination, and hole accuracy), as well as the cutting forces and temperatures. All the OD tests were performed under dry conditions using a four-flute 6.35 mm end-mill. The cutting forces were recorded using a 3-component dynamometer Kistler 9255B and cutting temperatures were measured using a FLIR ThermoVision A20M Infrared camera at the holes exit. A full factorial design of the experiment was used whereby the feeds varied from 60 to 360 mm/min and the speeds from 6,000 to 16,000 rpm. The test material used was a quasi-isotropic laminate comprising woven graphite epoxy prepreg. Analysis of the results showed 45% reduction in the axial force component in orbital drilling (OD), compared to conventional drilling. None of the holes produced by the entire set of experiments has experienced any entry or exit delamination. ANOVA was used to identify the significance of the controllable variables on the experimental outputs. To overcome the challenge of optimizing the competing parameters of the hole quality attributes while maximizing the productivity, an algorithm was applied by hybridizing Kriging as a meta-modeling technique with evolutionary multi-objective optimization to optimize the cutting parameters.


Author(s):  
Padmaja Tripathy ◽  
Kalipada Maity

This paper presents a modeling and simulation of micro-milling process with finite element modeling (FEM) analysis to predict cutting forces. The micro-milling of Inconel 718 is conducted using high-speed steel (HSS) micro-end mill cutter of 1mm diameter. The machining parameters considered for simulation are feed rate, cutting speed and depth of cut which are varied at three levels. The FEM analysis of machining process is divided into three parts, i.e., pre-processer, simulation and post-processor. In pre-processor, the input data are provided for simulation. The machining process is further simulated with the pre-processor data. For data extraction and viewing the simulated results, post-processor is used. A set of experiments are conducted for validation of simulated process. The simulated and experimental results are compared and the results are found to be having a good agreement.


Author(s):  
Bo Xue ◽  
Yongda Yan ◽  
Gaojie Ma ◽  
Zhenjiang Hu

This paper proposed a machining method for micro V-shaped grooves, which was achieved by introducing the revolving trajectory on the basis of tip scratching process. By coordinating the revolving direction and the tip orientation, four kinds of revolving scratches were developed which had the revolving radii larger than the groove depths. It was found that there were two revolving scratches among these four being able to eliminate the side burrs and produce much smaller cutting forces during machining grooves compared to the traditional scratch, respectively named as the up-milling of face-forward and the down-milling of edge-forward. By considering the tip geometry in the traditional scratching process, the burr formation has been studied which was mainly affected by the effect of chip interference and the amount of uncut chip thickness. By analyzing the machining trajectory, the undeformed chip, the machined surface and the chip morphology, the reason why the up-milling of face-forward and the down-milling of edge-forward had good performances for machining V-grooves was elucidated in detail. Meanwhile, the differences between these two revolving scratches were discussed, and their advantages and disadvantages were also given.


2015 ◽  
Vol 818 ◽  
pp. 233-238
Author(s):  
Krzysztof Szwajka

Particleboard is a wood based composite extensively used in wood working. Drilling is the most commonly used machining process in furniture industries. The surface characteristics and the damage free drilling are significantly influenced by the machining parameters. The thrust force developed during drilling play a major role in gaining the surface quality and minimizing the delamination tendency. In this study trials were made eighteen durability tools for different values of the parameters analyzed cut. Based on the results obtained from the study, the effect of cutting parameters selected signals of axial force and torque cutting. Proposed mathematical models using ANOVA, allowing to estimate the cutting forces.


2007 ◽  
Vol 359-360 ◽  
pp. 259-263
Author(s):  
Pai Shan Pa

In order to elevate the efficiency of the surface finish to reach the fast improvement of the surface roughness of the workpiece, so as to reduce the residual stress on the surface efficiently. The present study discusses the surface after traditional machining, of which the plane surface used a design of finish tool includes an electrode and a nonconductive grinding wheel to execute the synchronous process of grinding and electrochemical finishing. The electrode form and the machining process are obviously different from electrochemical grinding (ECG). In the experiment, the design electrode is used with continuous and pulsed direct current. The controlled factors include die material, and chemical composition and concentration of the electrolyte. The experimental parameters are flow rate of electrolytes, position of plate electrode, electrode thickness, electrode rotational speed, electrical current rating, feed rate of workpiece, and pulsed period. The experimental results show that the supply of current rating is near concern with the position and thickness of the plate electrode. The use of large electrolytic flow rate and thick electrode is advantageous to the finish effect. High rotational speed of finish tool produces better polishing. The finishing effect is better with longer off-time because discharge of polishing dregs becomes easier. Higher current rating with quicker workpiece feed rate effectively reaches the fast improvement of the surface roughness of the workpiece is recommend in current study.


Author(s):  
Vivek Bajpai ◽  
Ineon Lee ◽  
Hyung Wook Park

Titanium alloys are well-known material because of the excellent mechanical/chemical properties, corrosion resistance and light weight. These alloys are widely used in the high performance applications such as; aerospace, aviation, bio-implants, turbine blades etc. Machining is commonly used to create products out of Ti alloys. Despite of good material properties, Ti alloys have low thermal conductivity, poor machinability, burr formation, high machining temperature, tool wear and poor machinability. The tool wear and high machining temperature can be controlled through coolant. Cryogenic fluid (liquid nitrogen) is a common material used as coolant in various machining process. The current work is focused on the modeling of cryogenic machining on titanium alloy (Ti6Al4V). Dry machining and cryogenic machining processes are modeled for the chip formation and cutting forces in 2D. Experimental works have been performed to validate the model based on the cutting forces and chip morphology. It is showed that the model is capturing the process, evident by the cutting forces and the chip morphology. The error in prediction is limited to 18%. Model showed that the cutting forces are increasing in cryogenic machining due to the increased strength of the workpiece at low temperature. Chip formation is well captured by the current model. Shear band width have been captured in dry machining. Chip curling has been captured at dry and cryogenic machining. It is expected that the model can further useful in the selection of cryogenic process parameter, such as, flow rate, application techniques etc.


Sign in / Sign up

Export Citation Format

Share Document