Overview of Machining of Polymer Matrix Composites

Materials and Manufacturing Processes, 2004

Machining of fiber reinforced plastic (FRP) components is often needed in spite of the fact that most FRP structures can be made to near net shape. The material removal mechanism of FRP is very difficult as compared with metals due to their inherent inhomogeneity and anisotropy. This results in frequent fiber pullout, delamination, matrix burning, and other damages leading to poor cut surface quality. A finite element model is proposed to quantify the material damage, which has been experimentally validated by means of nondestructive dyepenetrant testing. Good agreement is observed for laminates with fiber orientations up to 60 . Divergence is noticed for higher fiber orientations, and the discrepancies increase with increasing fiber orientation. Proper interfacial properties vis-a`-vis machining of FRP materials are considered to be the main reasons for the divergence.

Conventional machining of polymeric composite materials is often both technically and economically less effective because the structural characteristics inherent in fibre reinforcement promote excessive tool wear. In recent years, abrasive waterjet machining (AWJM) has been proving to be successful in the machining of such materials. This paper presents a state of the art review of research in AWJM of polymeric composite materials. Among the main topics discussed are mechanisms of material removal, productivity and surface quality

2018

Currently, fibre reinforced composite materials are gaining more attention due to their specific advantages. Machining is an important process after preparation of material. Various machining operations (secondary operations) such as milling, drilling, turning and various unconventional processes are used for achieving near net shape and size of desired component. Fibre reinforced composite materials are less hard as compared to conventional materials so that less amount of cutting forces are required to achieve exact shape and size of desired component. Hence, a review on milling of fibre reinforced composite material will be helpful for various researchers and other manufacturing industries which are currently working in this field. This review shows detailed image of various issues which was occurred during milling of fibre reinforced composites. In addition, this review also represent different cutting parameters taken by various researchers during milling of fibre reinforced co...

This paper investigates, both experimentally and theoretically, the tool wear in the cutting of fibre-reinforced polymer composites as well as its effect on the surface integrity of the machined composites. It was found that the main mechanism is friction-caused flank wear, and that the introduction of ultrasonic vibration to the cutting tool can drastically reduce its wear rate. It was identified that tool wear not only influences cutting forces and chip formation as usually understood, but also affects significantly the material removal mechanisms and surface integrity of the machined composites. The study revealed that in a traditional cutting process, the chip formed by a fresh cutting edge is larger than that by a worn cutting edge, and that friction-induced bending fracture can occur in a machined subsurface as the tool wears out. The vibration-assisted cutting, however, reduces tool wear due to the much shortened tool-workpiece contact time in each cycle of the tool vibration.

Over the last decade, the use of polymeric composite material has increased considerably, and as a result, machinability of such material has also increased. The main aim of this work is to emphasize on the conventional and unconventional machining of composite materials, more specifically on drilling of carbon fiberreinforced polymer and glass fiber-reinforced polymer. Additional concentration on tool materials and geometry, roughness of drill surface, thrust force and delamination at entry and exit with influence of point angle of tool, variable feed rate, and variable spindle speed. Over the last few years, many studied on the effect of cutting parameters and tool geometry using conventional machining, the phenomena associated with unconventional machining of composite material requires some supplementary studies in order to make damage free machining of composite materials.

Journal of Natural Fibers, 2022

The natural, glass, and carbon fiber reinforced polymer composites are currently being replaced conventional materials due to their lower specific weight and superior strength properties. Natural fiber-reinforced polymer composites (NFRPCs) have grown in importance in real world applications recently due to a growing focus on the environmental and sustainability elements of engineering materials. The difficulty of machining FRP composites, which results in dimensional errors, poor product quality, and material damage, is due to their inhomogeneity, ease of deformation, and anisotropic nature. Moreover, this review gives an insight regarding recent developments and challenges that will help for upcoming researchers. The non-homogeneous properties and insufficient ductility of natural and synthetic fiber-reinforced composites have produced fracturing and discontinuous chips during the machining operations. The machinability of FRP composites depends on the constituents present in the composites. More delaminations were found in the natural fiber composites due to improper bonding and less compatibility with the polymer matrices, also the lower heat resistant property of the natural fibers causes serious problems during the machining process. Hence more studies are needed to decrease the thrust force and delamination damages in carbon, glass, and natural fiber reinforced polymer composites.

Composite materials are difficult to machine than metals mainly because they are anisotropic, nonhomogeneous and their reinforcing fires are very abrasive. During machining, defects are introduced into the work piece, and tools wear rapidly. Traditional machining techniques such as drilling or sawing can be used with proper tool design and operating conditions. In this article is presented a review of traditional machining methods applied to organic and matrix composite.

The surface integrity of a machined component influences its performance. For a fibre-reinforced polymer (FRP) composite, fragments in machining can be pushed into fractured surfaces, causing difficulties in the integrity examination experimentally. This paper presents a new numerical characterization method with the verification of microstructural examinations experimentally. Both conventional cutting and vibration-assisted cutting of unidirectional FRP composites with different fibre orientations were investigated. It was found that the new approach is convenient to show the fibre/matrix fracture and fibrematrix debonding. The application of the method also revealed that fibre orientation significantly influences the final surface topography and subsurface damage, and that the vibration-assisted cutting can largely minimise the subsurface damage. When fibre bending or fibre crushing dominates the fracture of fibres in cutting, the method showed the surface roughness and subsurface damage of the machined FRP composite decreases with increasing the fibre orientation, and that the surface quality is the best when the fibres are aligned in the cutting direction.

Engineering Science and Technology, an International Journal, 2016

The conventional homogeneous materials can no longer effectively satisfy the growing demands on product capabilities and performance, due to the advancement in products design and materials engineering. Therefore, the fibre reinforced composites (FRCs) with better properties and desirable applications emerged. These enhanced qualities of the FRCs have emphasized the need for analysing their machinability for further improvement of performance. Hence, this paper presents a comprehensive investigation on the machinability effects of drilling parameters (feed rate, cutting speed and thrust force), drill diameters and chips formation mainly on delamination and surface roughness of hemp fibre reinforced polymer (19/HFRP) and carbon fibre reinforced polymer (MTM 44-1/CFRP) composite laminates, using high speed steel (HSS) drills under dry machining condition. The results obtained depict that an increase in feed rate and thrust force caused an increase in delamination and surface roughness of both samples, different from cutting speed. Also, increased drill diameter and types of chips formation caused an increase in both delamination and surface roughness of both samples, as the material removal rate (MRR) increased. Evidently, the minimum surface roughness and delamination factor of the two samples for an optimal drilling are associated with feed rates of 0.05-0.10 mm/rev and cutting speed of 30 m/min.

Wear, 2011

A cutting induced-damage process involving matrix cracking, fiber fracture and interlaminar delamination often occurs when machining composite materials. Compared to metals, relatively little research has been carried out in this topic. Generally, damage mechanisms in machining composites include four types of wear modes: transverse matrix cracking, fiber-matrix interface debonding, fiber rupture and inter-ply delamination. The surface quality plays an important role in the improvement of fatigue life and wear resistance of composite components. In the case of high speed machining composite materials, the surface quality of the finished product may be improved by modifying the machining parameters. Due to the complex nature of this process, we focus here on the effect of cutting parameters on surface damage of the machined component and thus wear resistance. The later has been predicted using dynamic explicit finite element method. In this investigation a progressive failure analysis has been adopted for analysing damage process within the fiber reinforced polymer (FRP) workpiece. After damage is detected, selective stiffness degradation is applied to the workpiece material. It has been shown in this study that matrix cracking and interface shearing occur first, followed by wear of fibers. The damage progression in the matrix and interface occurs in parallel directions to the fiber axis. A random growth of fiber fracture has been observed and mainly localized in a plane with a specific direction. The effect of fiber orientation on wear resistance of the composite structure and cutting induced damage process has been investigated. Damage progression was found to be strongly influenced by the fiber orientation of the FRP composite.

This paper presents an overview of laser beam machining and researches carried out so far in the area of laser cutting of polymer matrix composites. Composite materials are highly promising materials for applications in the aeronautic, aerospace, automotive and marine industry, but their properties like brittleness, anisotropy and non-homogeneity make it a difficult to machine material by conventional machining methods. In order to make parts of the required specifications from composites an appropriate machining method must be selected and laser machining offers an attractive alternative for machining the composites. Laser machining is thermal energy based non-contact type advance machining. Laser beam is focused on the material to remove material by melting and vaporizing. Laser cutting of composites find wide application in industry due to improved end product quality, low cost and short processing time. In recent years number of researches have explored laser beam machining of p...

Journal of The Brazilian Society of Mechanical Sciences and Engineering, 2021

Polymeric composites have found wide acceptance in various industrial sectors, such as aerospace, automotive and marine industries because of a number of advantages that they have over conventional materials. Operational proficiency of these composites appreciably relies on their machinability. Conventional machining of polymeric composites causes different types of damages like fiber pull-out, matrix smearing, delamination, and poor surface quality of the machined surfaces, primarily due to anisotropic and inhomogeneous nature of composites. Advanced machining processes are preferred because of their easy operability, which facilitates machining of high-strength and anisotropic materials. Advanced machining methods have captivated huge attention in the areas of polymeric composites to fabricate complicated industrial components and fascinated production industries and the researchers. It has turned out eminent in all main areas of researches. However, some machining limitations arise during advanced machining of polymeric composites. These performance characteristics during machining of polymeric composites can be optimized by adding small loading of fillers in the polymeric matrix. This review paper presents research work, carried out on advanced machining methods, such as abrasive water jet and laser machining of filler-doped polymeric composite materials. It describes various aspects of research work, including those on parameters of process accuracy. The article concludes with a brief discussion on the future scope of researches in this field of studies.

Sains Malaysiana, 2021

Carbon fibre reinforced polymer composites (CFRP) is one of the common materials used in machining by various manufacturing industries. The most persistent challenges during the machining, both concerning the consistency of machined surfaces and the properties of the material, are the difficulties such as fibre pull-out, delamination, and decomposition of the material matrix. This preliminary research highlights the laser machining of thick CFRP using a fibre laser of more than 1 kW. Laser machining experiments have been conducted to examine the ability of the fibre laser machine to cut thick CFRP through their high-quality laser beams. Based on the results, the study showed how the heat affected zone can be reduced when the higher cooling period is used. The effects of modulated beam mode include substantial reductions in HAZ compared with other experimental results. In all experimental attempts, substantial damage has occurred. The results are important in assessing the relationsh...

International Journal of Materials and Product Technology, 2013

The use of end milling process for machining of fibre reinforced polymer composites has been widespread in various industries. Until recently, very little work has been reported with regard to characterisation of chip formation mechanisms while end milling these composite materials. This paper reports such study which was accomplished via high speed photography and quick stop procedure. It is apparent that the heterogeneity and insufficient ductility of the composites have produced discontinuous and fracturing chips. Information disclosed by the high-speed photography footages has shown that a layer of delaminated chip was formed as the tool cutting edge fractured the workpiece along the fibre orientation at the lowest cutting speed. The increased cutting speed accelerates the fracture of chips into smaller segments, which make it difficult to denote any chip formation processes. Similarly, shorter chip fragments were created as the tool cut at different fibre orientation (45° and 90° with respect to tool feed direction).

Polymers

Recently, natural fiber-reinforced polymers (NFRPs) have become important materials in many engineering applications; thus, to employ these materials some final industrial processes are needed, such as cutting, trimming, and drilling. Because of the heterogeneous nature of NFRPs, which differs from homogeneous materials such as metals and polymers, several defects have emerged when processing the NFRPs through traditional cutting methods such as high surface roughness and material damage at cutting zone. In order to overcome these challenges, unconventional cutting methods were considered. Unconventional cutting methods did not take into account the effects of cutting forces, which are the main cause of cutting defects in traditional cutting processes. The most prominent unconventional cutting processes are abrasive waterjet (AWJM) and laser beam (LBM) cutting technologies, which are actually applied for cutting various NFRPs. In this study, previously significant studies on cutting...