Investigation on Drilling Behavior of CFRP Composites Using Optimization Technique (original) (raw)
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Experimental Study on Drilling Process of CFRP Composite Laminate
Materials Science Forum, 2010
This thesis deals with carbon fiber reinforced plastics (CFRP) composites, an advanced material which is widely used in manufacturing aircrafts because of their unique mechanical and physical properties. The research mainly involved drilling of CFRP. This study is focused on analyzing the thrust force and delamination against drilling parameters namely feed rate, spindle speed and type of tool materials. Also, the optimal parameters were chosen using an optimization method called D optimal. It was observed that the higher the feed rate and spindle speed employed, the higher the thrust force and delamination occur. The split point fibre (SPF) drill gave the lowest values of thrust force and delamination. Based on the optimal parameters, a verification test was conducted and the prediction error was 2.3% and 5.6% for thrust force and delamination respectively. This shows, that the optimal parameters obtained is reliable as it could improve the process considerably. The results of this...
DRILLING OF CARBON FIBRE REINFORCED POLYMER MATERIALS -A REVIEW
Drilling is a secondary manufacturing process used for the finishing of the parts done in the primary manufacturing. For drilling of traditional materials, there are several techniques available to attain the objective of good circularity of the hole without any damage. Drilling of the CFRP material is difficult, because of its anisotropic and non-homogeneous in nature. Carbon fibre reinforced materials extensively used in the aerospace industries, because of its specific properties in strength and stiffness. Hence, the drilling of CFRP requires a lot of research for using in the aerospace industry. The principal aim of this paper is to present an extensive literature report in the drilling of CFRP and that includes the studies on different input variables such as machining parameters (speed, feed and drill point angle) and drill biton the drilling induced damages. Also, the study focuses effects of input variables on delamination and hole circularity and induced thrust force and torque.
2015
The demand of CFRP have been arises because of their capabilities and high strength to weight ratio properties. It has been remarkably used in most field nowadays as an example in aerospace industries as it provide weight reduction and reduce the fuel consumption at the same time. However, the inherent anisotropy, inhomogeneous properties of CFRP and low bonding strength within the laminates make machining of these composite materials results in several undesirable effects such as delamination, burr and chipping. This experimental study was conducted on drilling CFRP using 3mm-diameter ball nose Diamond coated, Titanium Aluminum Nitride (TiAlN) coated and uncoated tool. Relationship between the machining variables and the output variables is analyze and the tool that performs better were selected so that the experiments can be continue to prove the findings. It was observed that minimal delamination at entry and exit is achieved when using TIAlN at high spindle speed and feed.
Manufacturing Technology
Nowadays, Carbon Fibre Reinforced Polymer (CFRP) materials are extensively used as substitutes for metal parts in aircraft and automotive components since they are lighter in weight. However, micro drilling CFRP materials during the assembly process poses various challenges such as low hole accuracy and delamination. Hence, an experiment has been executed to investigate the influence of micro drilling parameters towards hole accuracy. The spindle speed and feed rate are the machining parameters that have been considered in this experiment. Three different optimum parameters have been obtained from previous experiments, involving the spindle speed combinations of 8,000, 10,762 and 11,017 min-1 with a feed rate of 0.01 mm/rev. A drill bit with a diameter of 0.9 mm is used to drill approximately 300 holes. It has been revealed that the combination of the spindle speed of 11,017 min-1 and feed rate of 0.01 mm/rev produce high hole accuracy at the 2 nd hole compared to the 300 th hole due to the presence of uncut fibres at the 300 th hole which have reduced the hole area. Hence, outcome of this research could provide the benefit to the industries in term of manufacturing time and materials expenditure.
Machining Characterization of CFRP Laminates with Respect to Drilling Operation-A Review
2013
Carbon Fiber Reinforced Plastic (CFRP) composite materials have potential applications in various domains. In machining, drilling is essentially required to join different structures. But CFRP drilling poses many problems that decrease the quality of holes. This paper reports an experimental investigation of a full factorial design performed on thin CFRP laminates using Solid carbide drill (Coated and Un coated both) by varying the drilling parameters such as spindle speed and feed rate to determine optimum cutting conditions. The hole quality parameters analyzed include hole diameter, Delamination, Surface roughness, Thrust force and Circularity. Analysis of variance (ANOVA) will carry out for hole quality parameters and their contribution rates will determine. Design of Experiments (DOE) methodology by full factorial Design will use in the multiple objective optimizations (using Mini Tab 16, a software) to find the optimum cutting conditions for defect free drilling.
In aerospace engineering, CFRP is a mostly used material for making different parts of aero planes. The CFRP material is a one of the composite material .Till now no any technique which is used to weld together of cfrp material.so that there is a only one technique is mostly used and that is a drill the hole and use the fasteners to join them. So that the quality of hole is very most important. Thus, the choice of optimized cutting parameters is very important for controlling the required hole quality. In this present work the aim is to optimized the cutting parameters through work piece hole size, circularity and delamination.in this research an experimental investigation of a full factorial design performed on thin CFRP laminated sheet using HSS drill with different point angle 90°,120°,150°and by varying different spindle speed (3500,4500,5500 rpm )and feed rate(200,500,900 mm/min )to determine optimum cutting condition. The hole quality parameters analyzed include hole diameter, circularity and delamination. Analysis of variance (ANOVA) was carried out for Hole quality parameters and their contribution rates was determined. Design of Experiments (DOE) methodology by full factorial Design was used in the multiple objective optimizations (using Mini Tab 17, software) to find the optimum cutting conditions for defect free drilling.
In drilling operation, the quality of hole is an important requirement for many applications. Thus, the choice of optimized cutting parameters is very important for controlling the required hole quality. The focus of present experimental study is to optimize the cutting parameters through work piece circularity and hole size. This paper reports an experimental investigation of a full factorial design performed on thin CFRP laminates using coated Solid carbide drill with point angle 60 0 and helix angle 30 0 by varying the drilling parameters such as spindle speeds (1500, 2500, 3500, 4500 and 6000 rpm) and feed rate (0.01, 0.03, 0.07, 0.1 and 0.15 mm/rev) to determine optimum cutting conditions. The hole quality parameters analyzed include hole diameter and circularity. Analysis of variance (ANOVA) was carried out for hole quality parameters and their contribution rates was determined. Design of Experiments (DOE) methodology by full factorial Design was used in the multiple objective optimizations (using Mini Tab 15, software) to find the optimum cutting conditions for defect free drilling.
The major objective of this work was to investigate a statistical model, based on Taguchi technique and to estimate the quality of drill in CFRP composite material prepared by hand layup technique. The design of experiments were made to investigate the influence of drill parameters such as cutting speed, feed rate and drill diameter on thrust force and delamination factor in drilling of CFRP laminates. Analysis of variance (ANOVA) was used to analyze the significance level of every drill parameters. The statistical model yields the results showing that the speed and feed rate were the major parameters affecting significantly the drilling process. Delamination due to drilling was analyzed by the stereomicroscope.
Analysis of Delamination Factor in Drilling of CFRP Composites Using Design of Experiments
The use of Carbon Fibre Reinforced Polymer (CFRP) composites has increased rapidly in recent times. Due to the complex cutting mechanism irregularities occur in the surface. The delamination factor should be minimized to obtain better surface quality. In this study, a CFRP composite material were drilled to experimentally minimize the delamination factor on the machined surfaces, using a drilling machine with different combinations of cutting parameters namely point angle, spindle speed, feed rate. Experimental results showed that the delamination factor increased rapidly with increasing spindle speed and lesser increase of delamination factor for feed rate and a very small change for point angle. In addition, analysis of variance (ANOVA) results clearly shows that the spindle speed was the most influential parameter affecting the delamination factor in drilling of CFRP composites. Response Surface Methodology (RSM) technique was adopted to optimize the responses and the relation between factors and response was plotted in 2D and 3D contour plots. 1. Introduction CFRP composites are already made to near net shape and machining is carried out for deburring, trimming and to achieve contour shape accuracy [1]. In CFRP metal removal is conducted at lower rates because small cutting depths produce smaller and fewer cracks. Most of the metals are replaced by Carbon Fibre Reinforced Plastics (CFRP) composite because they are economic and have high strength. They have a wide variety of applications in automotive, aircraft, construction, spaceship, interior design, sports goods and sea vehicles industries due to their light weight, high modulus, specific strength, high resistance to corrosion and high fracture toughness [2]. The machining of composite is different from the conventional machining of metal due to the composite's anisotropic and non-homogeneous nature [3].CFRP composite materials are extremely abrasive when machined. Thus the selection of the cutting tool and the cutting parameters is very important in the machining process [4]. During the process of machining of CFRP laminates due to the action of machining force the composites tend to delaminate and in order to improve the dimensional accuracy, performance and production, the cutting conditions that influence delamination factor should be optimized. For achieving the desired machining force, it is necessary to understand the mechanisms of the material removal, and the kinetics of machining processes affecting the performance of the cutting tool [5]. The machinability of the composites is mainly dependent on the cutting parameters namely spindle speed, feed and depth of cut. Paulo Davim and Mata (2007) proposed a new machinability index for turning FRP materials using polycrystalline diamond (PCD) and cemented carbide (K15) cutting tools. According to the study it was found that PCD tools had better surface finish and specific cutting pressure than cemented carbides [6]. Paulo Davim et al [7] established that the cutting parameters (feed and dept of cut) influence the machining force, delamination, dimensional precision and surface roughness in two composites (Viapal VUP 9731 and ATLAC 382-05). The orthogonal Design of Experiments of Taguchi has been applied to investigate the effect of the fiber orientation, the tool rake angle, the depth of cut, and the tool edge radius. The induced damage can strongly affect the surface roughness (surface quality of the work pieces) and considerably limits the use of these materials in many industrial applications. Satisfactory numerical results have been found and a good correlation has been obtained compared to experimental trends. The results reveal that the interaction between some factors could be neglected and the obtained responses are greatly influenced by the fiber orientation and the depth of cut rather than the tool rake angle and the tool edge radius [8]. Machining of composite materials, have shown that the surface quality (surface roughness), and delamination factor is strongly dependent on cutting parameters, tool geometry and cutting forces. [9-13]. In this study, the experiments were carried out using RSM technique the machining force was observed for second order response surface and the validity of the experiment was checked using analysis of variance (ANOVA). The machining parameters namely point angle, spindle speed and feed rate were selected in order to analyze the delamination factor. Response Surface Methodology (RSM) is a sequential process which involves a series of mathematical and statistical techniques which is used to analyze the problems and produce the optimizing the responses. By experimentation and regression analysis the independent variables of a response model are found and in turn used to find out the optimal point of the response. The relationship between control factors and response can also be found and respective 2-D and 3-D plots could be generated.
Composite Structures, 2016
This work investigates the influence of cutting speed and workpiece constituents on the thrust force and torque developed in the conventional dry drilling of woven carbon fibre reinforced polymer (CFRP) composites using uncoated WC-Co tools, by applying experimental techniques and statistical test methods. The type of thermosetting matrix showed significant impact on both the maximum thrust force and torque developed, whilst the type of carbon fibre fabric and cutting speed showed negligible effects on the maximum thrust force. Cutting speed exhibited a strong influence on the maximum torque developed; and high modulus CFRP composites showed increased sensitivity to cutting speed and strain rate compared with intermediate modulus composites. In the characteristic helical machining and feed directions in drilling, the strength and failure behaviour of the composite is dominated by the mechanical properties and failure mechanisms of the matrix, which explains the significant impact of resin on the cutting forces. On the other hand, the impact of cutting speed on torque is justified by the negative impact of strain rate on the ability of the matrix to transfer the load to the reinforcement, thus explaining the decreasing the maximum torque with the increasing cutting speed.