Experimental Investigations Towards Hole Accuracy in Micro-drilling of Carbon Fibre Reinforced Polymer Material (original) (raw)
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Carbon fiber reinforced polymers (CFRP) are increasingly employed within the aerospace industry, particularly within the aircraft sector. However, machining of fiber reinforced composites can be quite complex, first due to the inherent heterogeneity resulting from the reinforcements/matrix assembly and second due to the presence of high modulus/high strength fibers. In this dissertation work investigation on machining characterization of carbon fiber reinforced plastic is carried out for drilling operation with coated and uncoated twist drill. This investigation is carried out to find out hole quality parameters. Here comparison is made between the coated solid carbide drill conditions with the uncoated HSS drill condition for finding out the better one. In this study, the variable parameters, that affect much, are taken as input parameters. They are spindle speed, feed rate and point angle and output parameters are as Hole size and circularity and delamination.
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.
Investigation on Drilling Behavior of CFRP Composites Using Optimization Technique
Arabian Journal for Science and Engineering, 2020
Carbon fiber-reinforced polymers (CFRPs) have been applied to various fields such as electronic printed circuit boards, aircraft brakes, automobile forks, and machine tool-damped structures due to their low density and high tensile strength. These application components required micro-hole and macro-hole in it for joining. In this research work, a comparison of the experimental investigation on micro-and macro-drill on CFRP using a vertical machining center has been carried out. The input machining control factors were spindle speed and rate of feed, whereas the quality characteristics of drilling CFRP were considered as thrust force, delamination, and overcut. Analysis of variance (ANOVA) and gray relational analysis were employed to identify the most significant factor and optimum process parameters, respectively. Microstructural defects of micro-hole and macro-hole were studied using scanning electron microscopy. Results showed that the rate of feed linearly affected the thrust force and delamination and is inversely proportional to overcut.
OALib, 2021
Carbon fiber-reinforced polymer (CFRP) large diameter hole drilling is certifiably not a broadly examined theme on account of their non-homogeneity and anisotropic highlights. In the scope of aerospace industrial uses of this material, thousands of holes have to be machined for purposes of assembly. The quality of this machined hole is influenced adversely by matrix grid cratering, thermal damage, spalling, surface delamination, and material debasement or fiber pullout. Among these different deformities, delamination is considered the most severe for CFRP composite. The main objective of this work is to compare twist drilling, helical milling and pilot hole machining technologies concerning unidirectional CFRP composite. In addition, the force modules were also discussed. In the scope of this work, numerous machining experiments were conducted in unidirectional CFRP composite: herein the impact of the type of cutting tool and of process parameters on the quality of machined holes are analysed and discussed (diameter of holes, circularity error and characteristics of uncut fibres). In other to achieve a better hole quality, the Scanning electron microscope (SEM) analysis and evaluation of acquired data were conducted. Experimental results show holes machined using twist drilling method present the lowest-quality, with damages present at the tool entry and exit as compared to the other studied methods. This study intended to help in assisting technicians working on assembly large structural parts in aircraft or automobile industries in choosing the best hole machining procedure when this three are in consideration.
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.
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.
Recent advances in drilling of carbon fiber–reinforced polymers for aerospace applications: a review
The International Journal of Advanced Manufacturing Technology
Drilling is considered as one of the most challenging problems in aerospace structures where stringent tolerances are required for fasteners such as rivets and bolts to join the mating parts for final assembly. Fiber-reinforced polymers are widely used in aeronautical applications due to their superior properties. One of the major challenges in machining such polymers is the poor drilled-hole quality which reduces the strength of the composite and leads to part rejection at the assembly stage. In addition, rapid tool wear due to the abrasive nature of composites requires frequent tool change which results in high tooling and machining costs. This review intended to give in-depth details on the progress of drilling of fiber-reinforced polymers with special attention given to carbon fiber-reinforced polymers. The objective is to give a comprehensive understanding of the role of drilling parameters and composite properties on the drilling-induced damage in machined holes. Additionally, the review examines the drilling process parameters and its optimization techniques, and the effects of dust particles on human health during the machining process. This review will provide scientific and industrial communities with advantages and disadvantages through better drilled-hole quality inspection.
The most effective way of achieving good quality holes while drilling fibre reinforced plastics is by reducing the thrust and torque. Drilling experiments were conducted with drill points, namely standard twist drill, Zhirov-point drill, and multifacet drill, using wide range of spindle speed, and feed rate to analyse thrust force, delamination and surface roughness. At high spindle speed, cutting force is less and the special geometry improves the quality of the hole further, especially Zhirov point drill. Multifacet drill is found better as far as the delamination value is concerned.
International Journal of Materials and Product Technology, 2008
Aircraft manufacturing involves drilling of large number of holes, in which the joint can be critically affected by the quality of the hole. Effect of drill geometry on drilling of glass/epoxy laminates using twist, Zhirov and Multifaceted Drills (MFD), has been studied. The thrust force and hole quality were compared for each drill geometry. Zhirov drill cuts the hole with less force and best surface finish. MFD produces less delamination when compared with the other geometries. ANOVA was used to study the effect of drill geometries, spindle speed, and feed rate on thrust force, surface finish and delamination factor.