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Several challenges arise during edge trimming of carbon fibre-reinforced polymer (CFRP) composites, such as the formation of machining-induced burrs and delamination. In a recent development, appropriate-quality geometric features in CFRPs can be machined using special cutting tools and optimised machining parameters. However, these suitable technologies quickly become inappropriate due to the accelerated tool wear. Therefore, the main aim of our research was to find a novel solution for maintaining the machined edge quality even if the tool condition changed significantly. We developed a novel mechanical edge-trimming technology inspired by wobble milling, i.e., the composite plate compression is governed by the proper tool tilting. The effectiveness of the novel technology was tested through mechanical machining experiments and compared with that of conventional edge-trimming technology. Furthermore, the influences of the tool tilting angle and the permanent chamfer size on the burr characteristics were also investigated. A one-fluted solid carbide end mill with a helix angle of 0° was applied for the experiments. The machined edges were examined trough stereomicroscopy and scanning electron microscopy. The images were evaluated through digital image processing. Our results show that multi-axis edge-trimming technology produces less extensive machining-induced burrs than conventional edge trimming by an average of 50%. Furthermore, we found that the tool tilting angle has a significant impact on burr size, while permanent chamfer does not influence it. These findings suggest that multi-axis edge trimming offers a strong alternative to conventional methods, especially when using end-of-life cutting tools, and highlight the importance of selecting the optimal tool tilting angle to minimize machining-induced burrs. [ABSTRACT FROM AUTHOR]

Several challenges arise during edge trimming of carbon fibre-reinforced polymer (CFRP) composites, such as the formation of machining-induced burrs and delamination. In a recent development, appropriate-quality geometric features in CFRPs can be machined using special cutting tools and optimised machining parameters. However, these suitable technologies quickly become inappropriate due to the accelerated tool wear. Therefore, the main aim of our research was to find a novel solution for maintaining the machined edge quality even if the tool condition changed significantly. We developed a novel mechanical edge-trimming technology inspired by wobble milling, i.e., the composite plate compression is governed by the proper tool tilting. The effectiveness of the novel technology was tested through mechanical machining experiments and compared with that of conventional edge-trimming technology. Furthermore, the influences of the tool tilting angle and the permanent chamfer size on the burr characteristics were also investigated. A one-fluted solid carbide end mill with a helix angle of 0° was applied for the experiments. The machined edges were examined trough stereomicroscopy and scanning electron microscopy. The images were evaluated through digital image processing. Our results show that multi-axis edge-trimming technology produces less extensive machining-induced burrs than conventional edge trimming by an average of 50%. Furthermore, we found that the tool tilting angle has a significant impact on burr size, while permanent chamfer does not influence it. These findings suggest that multi-axis edge trimming offers a strong alternative to conventional methods, especially when using end-of-life cutting tools, and highlight the importance of selecting the optimal tool tilting angle to minimize machining-induced burrs.

Objective In engineering, the edge trimming method is often used to solve the problem of ship-machine-propeller mismatch caused by excessive load. In order to explore the effects of edge trimming on the vibration characteristics of the propeller, this paper studies the vibration of a propeller with edge trimming based on parametric modeling. MethodsDTMB4381, DTMB4382 and DTMB4383 propellers are selected as research examples, then Matlab programming technology and the ANSYS secondary development program are combined to obtain the influence laws of different unilateral edge trimming on the vibration characteristics of the propeller, and the different reasons behind the corresponding influence laws are analyzed. ResultsFor the DTMB4381 propeller without skew, the natural frequency increases slightly with the increase of the edge trimming amount, but the mode shape does not change much. For the DTMB4382 and DTMB4383 propellers with skew, with the increase of the edge trimming amount, the change law of the natural frequency remains basically the same as that of the DTMB4381 propeller without skew. ConclusionsSkew does not change the vibration characteristics of a propeller under different unilateral trimming amounts; with the increase of the trimming amount, the natural frequency change rate of the two types of propeller shapes after chamfering will be significantly improved, and the increase is more pronounced at higher levels. The corresponding secondary development program can help the relevant personnel to select the optimal trimming scheme from the perspective of vibration characteristics in practical engineering, providing a theoretical basis and guidance for the design and improvement of trimming schemes.

Cutting force plays an important role in the analysis of machining dynamics. In trimming of thin-walled structures, the stick-out length of the workpiece is very large when compared with the traditional milling process, which may result in a large vibration velocity along the tool axis. Since the amplitude of the vibration velocity of the workpiece is comparable to that of the tool velocity caused by the rotary motion of the spindle, it affects the relative velocity between the tool and the workpiece, making the trimming process an oblique cutting process with a time-varying inclination angle, instead of a constant value β , the helix angle of the tool. To this end, we developed a dynamic cutting force model to investigate this effect, and compared simulated and dynamometer-measured cutting forces to validate the established model. The results show that the vibration velocity of the workpiece in the trimming process has a modulating effect on cutting forces, which can significantly reduce the amplitude of the cutting force along the tool axis. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced plastics (CFRP) composites are difficult-to-machine materials due to extensive tool wear. This article investigates the impact of carbon fiber types on tool wear in edge-trimming CFRPs, each with the ply angle of 0 deg, 45 deg, 90 deg, or 135 deg, using uncoated tungsten carbide endmills at the high spindle speed of 6000 rpm and the constant feed of 0.0508 mm/rev. Three distinct types of carbon fiber tows, including T300 as standard modulus (SM), IM-7 as intermediate modulus (IM), and K13312 as high modulus (HM), have been vacuum infused into CFRP laminates and edge trimmed to investigate wear characteristics. Three wear criteria measured are flank wear, edge rounding radii, and worn area. The results show that tool wear is influenced by carbon fiber properties, such as fiber tensile strength, tensile modulus, and fiber microstructure. Overall, IM carbon fibers with the highest tensile strength produced the most extensive tool wear due to the abrasive carbon fibers. Of four fiber directions, the largest tool wear was obtained from the 45 deg angle, while the lowest tool wear occurred in the 0 deg angle. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) composites are widely used in the aerospace field because of their outstanding lightweight material characteristics, tensile strength, and stiffness properties. The tools used in composite machining exhibits different cutting performance and machining quality under different cutting conditions. The combination of tool material, tool geometry, and cutting conditions strongly influence the tool life and surface quality of the machined parts. Edge trimming of CFRP blanks with tungsten carbide two flute end mill cutter was conducted. The operation was carried out on a computer numerical control (CNC) router by varying cutting speed, feed speed, and depth of cut. Experimental results indicated that the wear of carbide tools is characterized by abrasive wear and rounding of the cutting edge. This occurred mainly by hard abrasion of the carbide grains. Tool life was observed to be inversely proportional to cutting speed, feed speed, and depth of cut. An expanded tool wear equation with power, average temperature, and resultant force as independent variables provided higher tool wear predictive capabilities. To check the adequacy of the regression model, validation runs were conducted. The experimental tool wear obtained from validation experiments were compared with the tool wear obtained using regression. An approximate average error of 5 % confirms that the experimental and regression tool wear values are very close. The equations and analysis permit trimming of CFRP to be designed such that tool wear is optimized and well forecasted. [ABSTRACT FROM AUTHOR]

The main aim of this research was to investigate the effect of machining parameters towards surface quality during edge trimming process on a specific CFRP material. There were two variation of machining parameters focused in this work namely spindle speed (N) and feed rate (Vf). The CFRP panel is measured 3.25 mm in thickness and the type of fabric was unidirectional (UD). It has 28 number of plies in total and were arranged multi-directional. Router or burr tool geometry made of uncoated tungsten carbide with a diameter of 6.35 mm was used to perform the edge trimming process. Surface roughness measurement was taken using Mitutoyo Surftest SJ-410. Furthermore, optical microscope Nikon MM-800 is utilized to further observe the trimmed surfaces. The result reveals that the smallest value of the surface roughness (1.31 µm) is obtained by Run 8 (R8) which the spindle speed, N applied was 2506 rpm and feed rate, Vf at 376 mm/min. Meanwhile, the highest surface roughness value (12.62 µm) exhibited by the R9 which had the highest setting of spindle speed, N 7518 rpm and the highest feed rate, Vf 1128 mm/min. The result is supported by the observation of trimmed surface through optical microscopy which clearly exhibits uncut fibers and matrix degradation condition. Details results elaborated and discussed further in this paper.

Machining of CFRP composites is usually described as a challenging process from tool life and surface quality perspectives. To achieve a flawless machined surface at reasonable cutting tool life/cost, an optimum combination of cutting tool material and geometry is the key. The cutting tool angles are of importance as these dictate the cutting mechanism as well as the cutting edge robustness and the introduction of vibration to the machining process opens up new horizons of improvement and stirs further research questions. This article investigates the effect of tools with different geometry possessing different rake angles when used in ultrasonic-assisted edge trimming operation dealing with multidirectional CFRP laminates. A full-factorial experimental design was adopted to analyze the effect of process parameters typically cutting speed, feed rate, rake angle, amplitude, and their interactions. Machining performance indicators were captured which were the cutting forces, tool wear, chip temperature, and surface roughness. The results showed that UAM mode contributed to an increase in the cutting forces, tool wear, and chip temperature compared to the conventional mode. On the other hand, UAM mode improved the quality of the machined surface. Additionally, the ultrasonic mode enhanced the material removal mechanism using a tool with a negative rake angle. [ABSTRACT FROM AUTHOR]

Nowadays, the development of robust finite element models is vital to research cost-effectively the optimal cutting parameters of a composite machining process. However, various factors, such as the high computational cost or the complicated nature of the interaction between the workpiece and the cutting tool significantly hinder the modelling of these types of processes. For these reasons, the numerical study of common machining operations, especially in composite machining, is still minimal. This paper presents a novel approach comprising a mixed multidirectional composite damage mode with composite edge trimming operation. An ingenious finite element framework which infer the cutting edge tool wear assessing the incremental change of the machining forces is developed. This information is essential to replace tool inserts before the tool wear could cause severe damage in the machined parts. Two unidirectional carbon fibre specimens with fibre orientations of 45 ° and 90 ° manufactured by pre-preg layup and cured in an autoclave were tested. Excellent machining force predictions were obtained with errors below 10% from the experimental trials. A consistent 2D FE composite damage model previously performed in composite machining was implemented to mimic the material failure during the machining process. The simulation of the spring back effect was shown to notably increase the accuracy of the numerical predictions in comparison to similar investigations. Global cutting forces simulated were analysed together with the cutting tool tooth forces to extract interesting conclusions regarding the forces received by the spindle axis and the cutting tool tooth, respectively. In general terms, vertical and normal forces steadily increase with tool wear, while tangential to the cutting tool, tooth and horizontal machining forces do not undergo a notable variation. [ABSTRACT FROM AUTHOR]

The main aim of this work was to investigate the effect of machining conditions namely cutting speed (Vc) and feed per tooth (fz) towards the surface finish during the edge trimming process on a specific CFRP material. The range of cutting speed (Vc) applied was 50 m/min (low), 100 m/min (middle) and 150 m/min (high) whilst for the feed per tooth (fz); 0.05 mm (low), 0.10 mm (middle) and 0.15 mm (high). The CFRP panel is measured 3.25 mm in thickness and has 28 plies in total. Router or burr tool made of uncoated tungsten carbide with a diameter of 6.35 mm is used to perform the edge trimming process. The Taguchi technique has been adopted to plan the overall experimental process. Surface roughness measurement was taken using Mitutoyo Surftest SJ-410 and optical microscope Nikon MM-800 is utilized to further observe the quality of the trimmed surfaces. From the ANOVA analysis, both factors namely cutting speed, Vc and feed per tooth, fz indicated a significant result towards the surface finish of the trimmed surfaces. The result is supported by the observation via optical microscopy which clearly exhibits uncut fibers, fiber pull-out and matrix degradation conditions. Detailed results are elaborated and discussed further in this paper. [ABSTRACT FROM AUTHOR]

Thermal loading of fiber reinforced composites during traditional machining is inevitable. This is due to the fact that most of the mechanical energy utilized in material removal is converted into heat, which is subsequently dissipated into the workpiece, the cutter and is carried away by the chips. Heat conduction into the workpiece might cause thermal damage if the generated temperatures exceeded the glass transition temperature of the epoxy matrix. In this work, the amount of heat flux applied to the machined edge and the temperature distribution in a multidirectional GFRP composite laminate was determined using an inverse heat conduction method. The spindle electric power, cutting forces and boundary temperatures on the workpiece were measured during edge trimming of the GFRP laminate with a PCD cutter at different spindle and feed speeds. The transient heat conduction problem in the laminate was simulated using the finite element method and the amount of heat flux conducted through the machined surface was determined. It was found that the heat flux conducted to the workpiece represented only a small fraction of the total heat and is more influenced by the feed speed than the spindle speed. The temperature of the machined surface was found to be lower than the glass transition temperature of epoxy for all cutting conditions tried in this study. [ABSTRACT FROM AUTHOR]

Nowadays, the development of robust finite element models is vital to research cost-effectively the optimal cutting parameters of a composite machining process. However, various factors, such as the high computational cost or the complicated nature of the interaction between the workpiece and the cutting tool significantly hinder the modelling of these types of processes. For these reasons, the numerical study of common machining operations, especially in composite machining, is still minimal. This paper presents a novel approach comprising a mixed multidirectional composite damage mode with composite edge trimming operation. An ingenious finite element framework which infer the cutting edge tool wear assessing the incremental change of the machining forces is developed. This information is essential to replace tool inserts before the tool wear could cause severe damage in the machined parts. Two unidirectional carbon fibre specimens with fibre orientations of 45° and 90° manufactured by pre-preg layup and cured in an autoclave were tested. Excellent machining force predictions were obtained with errors below 10% from the experimental trials. A consistent 2D FE composite damage model previously performed in composite machining was implemented to mimic the material failure during the machining process. The simulation of the spring back effect was shown to notably increase the accuracy of the numerical predictions in comparison to similar investigations. Global cutting forces simulated were analysed together with the cutting tool tooth forces to extract interesting conclusions regarding the forces received by the spindle axis and the cutting tool tooth, respectively. In general terms, vertical and normal forces steadily increase with tool wear, while tangential to the cutting tool, tooth and horizontal machining forces do not undergo a notable variation.

A main requirement in the field of polymer composites milling with fibre reinforcement is to machine with high quality in one operation (without delamination or burrs). That requires precise selection of cutting tool geometry and cutting conditions. Fibre-reinforced plastics (FRPs) are difficult-to-machine materials due to high abrasivity, relatively low melting point of polymeric matrices and inclination to delamination or large burr formation. This study investigates the main factors influencing the forces, temperature and surface quality in terms of the cutting conditions through ANOVA testing. Machining during this experiment was performed with a polycrystalline diamond (PCD) end mill. Next, the strongest factor with various double-helix cutting tool geometry was compared. The geometric model of the cutting forces was created based on previous measurements as well as a general empirical model of cutting forces, temperature on the machined surface and average delamination length for C/PPS material. [ABSTRACT FROM AUTHOR]

Edge trimming is commonly used to bring the CFRP components to right dimension and shape in aerospace industries. However, various forms of undesirable machining damage occur frequently which will significantly decrease the material performance of CFRP. The damage is difficult to predict and control due to the complicated changing laws, causing unsatisfactory machining quality of CFRP components. Since the most of damage has the same essence: the fiber-matrix interface cracks, this study aims to calculate the distribution of them in edge trimming of CFRP, thereby to obtain the effects of the machining parameters, which could be helpful to guide the optimal selection of the machining parameters in engineering. Through the orthogonal cutting experiments, the quantitative relation between the fiber-matrix interface crack depth and the fiber cutting angle, cutting depth as well as cutting speed is established. According to the analysis on material removal process on any location of the workpiece in edge trimming, the instantaneous cutting parameters are calculated, and the formation process of the fiber-matrix interface crack is revealed. Finally, the computational method for the fiber-matrix interface cracks in edge trimming of CFRP is proposed. Upon the computational results, it is found that the fiber orientations of CFRP workpieces is the most significant factor on the fiber-matrix interface cracks, which can not only change the depth of them from micrometers to millimeters, but control the distribution image of them. Other machining parameters, only influence the fiber-matrix interface cracks depth but have little effect on the distribution image. [ABSTRACT FROM AUTHOR]

Highlights • Tool wear is influenced most by the feed speed and the depth of cut. • TOPSIS optimization works well in combination with neural networks generalization. • Sensor infusion in the neural networks training vector improves data generalization. • Optimum cutting conditions consisted of (N4000 rpm, F1000 mm/min, D2.5 mm). Abstract This work presents the results of an optimization study of trimming carbon fiber composite by technique of order preference by similarity to ideal solution (TOPSIS). Edge trimming was conducted at different levels of cutting speed, feed speed, and radial depth of cut using a 2 k factorial design. The effects of cutting parameters on tool wear, surface roughness and tool temperature were analyzed and discussed. Data generalization was performed by training multiple neural network structures (NN) where the input vector of the neural networks contained sensor data in addition to typical process parameters. TOPSIS was used to select the optimal cutting conditions that could generate minimum tool wear, surface roughness, and tool temperature simultaneously while maintaining high production rates. The results show that the NN models offer better results when sensor data is fused in the input vector. TOPSIS optimum conditions were confirmed by validation experiments and were found to be accurate. [ABSTRACT FROM AUTHOR]

Delamination factor is one of the most important factors evaluating the surface integrity of carbon fiber–reinforced polymer laminates. The value of the delamination factor in edge trimming of carbon fiber–reinforced polymer laminates controlled the acceptance or rejection of the machined component. Therefore, using a reasonable and efficient approach to characterize the delamination region is very beneficial. However, the conventional delamination factor is a one-dimensional evaluation method, and hence, it cannot distinguish the delamination extent of carbon fiber–reinforced polymer laminates after edge trimming. The contribution of this work is to present a novel assessment approach to characterize the cutting-induced delamination using a milling cutter and compare it with the conventional delamination factor. The experimental results indicated that the delamination factor based on area assessment method is suitable to evaluate the delamination extent at the top layer after edge trimming. [ABSTRACT FROM AUTHOR]

The superior properties make carbon fiber-reinforced plastic (CFRP) composites attractive in many applications. After CFRPs’ molding processes, additional machining processes are needed to produce final functional shapes with dimensional precision. Edge trimming is the primary process to cut the edge of CFRP composites. To reduce or further solve the problems in traditional machining processes, edge trimming of CFRP composites with rotary ultrasonic machining (RUM) has been proposed and conducted in this investigation. In RUM edge trimming processes, two different tool orientations (RUM edge trimming with tool end face and RUM edge trimming with tool side face) can be performed. The comparisons of machining performance and machined surface quality between these two different RUM edge trimming processes have been conducted. Smaller ultrasonic vibration amplitude in RUM using tool end face or larger ultrasonic vibration amplitude in RUM using tool side face produces smaller surface roughness. Lower feeding-directional cutting force, lower normal cutting force, and lower resultant force are generated in the process using tool side face. RUM using tool end face produces smaller surface roughness, smaller debris width, microcracking, flowed matrix on machined CFRP surfaces, etc. [ABSTRACT FROM AUTHOR]

Recently, the use of carbon fibre reinforced polymer (CFRP) composites is predominant and will grow further. Although these fibrous composites are often manufactured near net shape, their mechanical machining is often required to meet dimensional tolerances. Considering the difficult-to-cut nature of CFRP composites, the technology planning of edge trimming of CFRPs poses significant challenges and obstacles. Therefore, the main aim of this study is to critically review and discuss challenges, recent expertise and experience gained in the area of edge trimming CFRPs. On the one hand, conventional and advanced edge trimming technologies are reviewed and compared. On the other hand, advanced cutting tools are presented and discussed. Finally, future scope and prospects are highlighted to determine further research scopes in the edge trimming of CFRP composites. [ABSTRACT FROM AUTHOR]

Edge trimming of CFRP composite laminates, using abrasive tools, is needed as a finishing operation for better quality and dimensional accuracy. Fiber delamination and resin burning are the major difficulties associated with traditional machining processes of CFRP. Although dry cutting is preferable for cutting CFRP which not absorb cutting fluid and eliminate the need for subsequent cleaning, increasing cutting temperature leads to degradation, smearing, and burning of epoxy resin. This paper investigates the effect of different fluid delivery methods (MQL/flood) on ultrasonic assisted machining (UAM) of multidirectional CFRP laminates using diamond abrasive tools at different cutting conditions. The process parameters studied were cutting speed, feed rate, radial depth of cut, and cooling modes. Cutting forces, surface integrity, and bouncing-back effect were the output responses of this study. Statistical analysis was conducted to study the effect of each factor on the performance characteristics. The results showed that flood coolant provide better results than MQL. However, MQL responses still comparable with flood coolant. The conditions that gave the best responses of MQL were determined which can be utilized for near dry cutting demands. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced plastics (CFRPs), have excellent mechanical properties such as high modulus, fatigue strength and specific tensile strength have increasingly been used in various applications. Although the CFRP components are made to near net shape using different composite moulding techniques, the components are needed to be machined with some post machining processes like edge trimming. Edge trimming is normally done with end mills of different geometry and materials. The quality of the trimmed edges and life of the tool used depend on the type of tool material and tool geometry and cutting parameters. In this paper, coated router tools (also called as burr tools) with typical geometry have been selected for studying the surface roughness of CFRP work material and tool wear. The study was done with three types of tungsten carbide router tools namely uncoated carbide, AlTiN (Aluminium Titanium Nitrate) coated carbide, DLC (Diamond Like Carbon) coated carbide. Due to the complexity of geometry, the tool wear of this kind of router tool was indirectly monitored and measured using the acoustic emission (AE) signals. The optimization was done by considering the multiple objectives of minimum surface roughness and minimum tool wear using two different optimization techniques namely genetic and differential algorithms. The salient parameters which are considered for optimization are spindle speed, feed rate and coating material. A comparison study of the optimized results obtained from both of these optimization techniques with experimental results has been madein order to identify their suitability for using for optimization in machining of CFRP materials. [ABSTRACT FROM AUTHOR]

Delamination occurs in edge trimming of CFRP on the surface plies due to lack of support and is known to depend on feed rate, cutting speed, and tool wear. Burr tools have complex geometries with ill-defined cutting edges and surfaces, and the traditional method of wear measurement is not readily applicable to them. This paper presents and discusses an alternative method for defining tool life for tools with complex geometries, and the application of this method to burr tools is demonstrated. The approach relies on the effect of tool deterioration, rather than the physical wear itself, to define a tool life criterion and a tool life equation. In this study, an indirect technique is used to quantify the tool wear based on delamination. The damage caused by delamination on the composite material undergoing edge trimming operation is quantified in terms of delamination depth and frequency of occurrence per given length. A proper tool life criterion is then defined based on acceptable industry practices, and an empirical tool life equation was developed as a function of cutting speed and feed rate. The new tool life equation was validated by experiments. [ABSTRACT FROM AUTHOR]

Characterization of the damage induced by machining of fibre-reinforced composites is usually performed by measuring surface roughness. Contact-based surface profilometers are the most used equipment in industry; however, it has been found that there are performance limitations which may result when used to measure machined heterogeneous composite surfaces. In this research, surface roughness is characterised using a commercial non-contact optical method, and compared with a conventional stylus profilometer. Unidirectional and multidirectional carbon fibre laminates were edge trimmed and slot milled. The variation in surface roughness was compared using different tool types, fibre orientations and cutting parameters. Surface damage and cutting mechanisms were assessed by using scanning electron microscope images, and the suitability of roughness parameters were also analysed including: Sa, Skewness and Kurtosis. Using the optical system allowed accurate roughness calculation of individual plies on a multidirectional laminate with different fibre orientations. The research has also shown that the optical system, including the use of areal roughness parameters, can increase the accuracy of roughness measurement for machined fibrous composite surfaces and is less sensitive to measurement position than the stylus. [ABSTRACT FROM AUTHOR]

The impact of the edge trimming process on permanently bonded wafers is described. The edge trimming process is a blade sawing process applied on the Si wafer edge and bevel, removing the fragile edge of the wafer prior to grinding. We investigated two routes for the integration on permanently bonded Si wafers, edge-trim before bonding and edge-trim after bonding. The impact on the subsequent processes for both integration routes is assessed. For the case of edge-trim before bonding, a combination of functional water cleaning such as ozone dissolved in water and ammoniac scrub cleaning shows a significant effect to remove Si residues, enabling void free dielectric bonding. For the case of edge-trim after bonding, utilizing a small grit diamond blade shows no mechanical failures into the dielectric bonding interface. These proposed processes are a very promising for the fabrication of extreme thinned Si without mechanical failure at wafer edge. [ABSTRACT FROM AUTHOR]

2D and 3D finite element models were developed to simulate the machining of CFRP with different levels of tool wear. Models were validated by edge trimming experiments on a uni-directional laminate at different fibre orientations using a three flute PCD milling tool. MSC Marc was used to develop the model and in conjunction with a Hashin damage material model. Modelling results are validated according to measured cutting forces at different cutting speeds and feed rates. A percentage difference of +10% and +5% was calculated for the 3D model for Fx and Fy respectively, while a percentage difference of -9% and -50% was found for the 2D model. Tool wear was found to have a significant effect on measured cutting forces. [ABSTRACT FROM AUTHOR]

Better control of fibre composites machining requires reliable surface roughness and damage characterisation measurements. The performance and tool wear rate of three different state of the art CVD and PCD cutting tools manufactured for carbon fibre machining were compared in wet and dry conditions. Machined surfaces were characterised by areal surface roughness parameters using a novel focus variation optical system. The tool wear and cutting forces were recorded up to 50 linear meters of machining or until tool failure. Results showed that wet machining conditions reduced tool failure; and that the CVD tool in wet conditions machined the greatest distance of 26m before reaching an average roughness limit of 3 μm. The tool type was found to be the most significant parameter on the surface quality. The optical system was found to be a useful tool for measuring roughness of individual plies and characterising machining induced surface damage. [ABSTRACT FROM AUTHOR]

Increasing application of carbon fibre reinforced plastic (CFRP) in lightweight constructions in aerospace, automotive and other industries requires high-performance cutting processes for edge trimming of thin shell structures. As an alternative to conventional processes, e.g. milling, a rigid abrasive circular saw blade is introduced. The limitation of cutting only almost-straight contours with circular saw blades is overcome by a novel tool geometry and process kinematic that allows curve cutting with radius $$R < 500$$ mm on thin plane material (thickness $$t<10$$ mm). The kinematic for cutting almost arbitrarily shaped outlines with a circular tool on a five-axis machine is described and proven by cutting a reference component. Besides high operating efficiency because of high feed rate the process features sound edge quality without noteworthy delamination of the outer layers, which is shown in pilot tests on CFRP with unidirectional top layers. [ABSTRACT FROM AUTHOR]

Conventional machining processes such as turning, milling, drilling, abrasive cutting, and grinding are commonly used to bring composite parts to final shape and assembly requirements. However, due to the layered nature of these materials, their machining may generate undesirable defects such as delamination and high surface roughness. The service life of composite components is believed to be highly dependent on machining quality and damage due to machining may result in scraping expensive parts. In this work, an experimental investigation was conducted to determine the effect of spindle speed, feed rate, and tool condition on machining quality of carbon fiber reinforced polymer (CFRP) composites during edge trimming operation. Machining quality was quantified in terms of average delamination depth and surface roughness. Delaminations were also characterized by their type and frequency of occurrence. It was found that average delamination depth and surface roughness increase with an increase in feed rate and an increase in cutting distance and decrease with an increase in spindle speed. There is a strong relationship between delamination damage and effective chip thickness. The cutting conditions for best machining quality are high spindle speed and low feed rate, which correspond to small effective chip thickness. The most frequent delamination type was found to be Type I/II. [ABSTRACT FROM PUBLISHER]

This paper deals with an original study on serration, supposed to be the result of residual stresses in the strip metal edge, due to edge trimming and revealed during the cold rolling process. The aim of this research work is to predict the formation of serration and the finite element methodology will be used to model edge trimming. The first part of this paper focuses on the simulation of the process using two fracture criteria and the Lemaitre’s damage model which have been implemented into a Vectorized User MATerial (VUMAT). The configuration of the damage model coupled to a fracture criterion is also considered. A 2D numerical model of edge trimming is created to validate the accuracy of the implemented models by comparison of the crack profiles obtained by finite element simulation with those obtained in industrial conditions. The second part of this work concerns the 3D model of edge trimming. A special attention is given to the meshing of this model to obtain a realistic crack profile and an accurate residual stress state on the strip edge. [ABSTRACT FROM AUTHOR]

Delamination is one of the main problems that occur when machining fiber-reinforced composite materials. In this work, Types I and II of delamination are studied separately in edge trimming of basalt fiber reinforced plastic (BFRP). For this purpose, one-dimensional and area delamination parameters are defined. One-dimensional parameters (Wa and Wb) allow to know average fibers length while the analysis of area delamination parameters (Sd) allow to evaluate delamination density. To study delamination, different tests are carried out modifying cutting parameters (cutting speed, feed per tooth and depth of cut) and material characteristics (fiber volume fraction and fiber orientation). Laminates with a lower fiber volume fraction do not present delamination. Attending to one-dimensional parameters it can be concluded that Type II delamination is more important than Type I and that a high depth of cut generates higher values of delamination parameters. An analysis of variance (ANOVA) is performed to study area parameters. Although delamination has a random nature, for each depth of cut, more influence variables in area delamination are firstly, feed per tooth and secondly, cutting speed. [ABSTRACT FROM AUTHOR]

Although there are many machining studies of carbon and glass fiber reinforced plastics, delamination and tool wear of basalt fiber reinforced plastics (BFRP) in edge trimming has not yet studied. This paper presents an end milling study of BFRP fabricated by resin transfer molding (RTM), to evaluate delamination types at the top layer of the machined edge with different cutting conditions (cutting speed, feed rate and depth of cut) and fiber volume fraction (40% and 60%). This work quantifies delamination types, using a parameter Sd/L, that evaluates the delamination area (Sd) and the length (L), taking into account tool position in the yarn and movement of yarns during RTM process, which show the random nature of delamination. Delamination was present in all materials with 60% of fiber volume. High values of tool wear did not permit to machine the material due to an excessive delamination. Type II delamination was the most usual delamination type and depth of cut has influence on this type of delamination. [ABSTRACT FROM AUTHOR]