Chip Formation Research Articles

Machinability performance of different fiber orientations of roll wrapped CFRP pipes

AbstractIntegrating fiber reinforcement plastics (FRP) materials into the industry plays a key role especially for pipes. However, due to the production methods of CFRP pipes, surface finishing processes are inevitable at the end of production. Despite the widespread use of CFRP materials, the predominant focus in the literature has been on their mechanical performance. This study aims to contribute to the limited research on the machinability of CFRP materials. In this context, the turning machining process for CFRP pipes was experimentally investigated in the present study. For this purpose, carbon fiber pipes with an inner diameter of 30 mm and an outer diameter of 60 mm were produced and subjected to computer numerical control (CNC) turning. First, a cylindrical aluminum pipe is used as a mold to manufacture CFRP pipes. Unidirectional (UD) carbon fabrics were wrapped on these aluminum molds. Shrink tape was used to enhance the surface smoothness and required pressure to prevent delaminating of the end product during the process. UD carbon fabrics are wrapped on to the mold at the selected angles (0°, 45°, and 90°) and the CFRP pipe specimens were manufactured using epoxy matrix. Pipes were processed on CNC lathe at 120, 160, 200 rev/min speeds and f 0.4 mm/rev feed rate. The surfaces of the machined specimens were measured with a microscope and a surface roughness device. On the other hand, wear on the tools was observed after the process.Highlights CFRP pipes were produced with different fibre orientations, i.e., 0°, 45°, and 90°. All CFRP pipes are made under equal conditions and cured at 80°. Turning of CFRP pipes was examined under dry environments. Performance criteria: surface roughness, temperature, tool wear, and chip formation were explored. 45° fibre angles CFRP pipes showed the best machinability performance.

82 Relationships between performance traits and osteochondrosis of the hock in Standardbred racehorses

Abstract Equine osteochondrosis (OC) is a developmental orthopedic disease that results in abnormal articular cartilage and often the formation of osteochondral bone chips (osteochondrosis dissecans). Standardbreds, a breed predominately used in harness racing, are prone to the development of OC. This study aimed to quantify the relationship between OC and key performance traits, fastest mile time, annual earnings, and consistency in race times over career, using a cohort of 347 North American Standardbred horses. Radiographic examination of the tarsi was previously performed to identify horses as OC-affected (n = 155) or healthy (n = 192). Performance data was acquired from the United States Trotting Association (USTA) detailing horse identification, performance, and lifetime race record. Linear mixed multiple regression models were constructed to evaluate the relationship between OC and performance. A total of 24 performance related variables (e.g., age, gait, track) were evaluated for inclusion in the model through subset variable selection and goodness of fit as determined by Schwarz’s Bayesian Information Criterion (SBC). Preliminary results indicate that healthy horses exhibit significantly faster mile times (P < 0.001) compared with their OC-affected counterparts. However, no significant association was detected between OC status and annual earnings (P > 0.2) or consistency in race times over career (P > 0.2). Ongoing analyses are currently being conducted to assess additional predictors and performance variables for a potential association with osteochondrosis. This study emphasizes the importance of implementing effective strategies for OC management and improving breeding selection practices when producing offspring with desired performance characteristics.

Theoretical and experimental investigation of ultrasonic cutting kinematics and its effect on chip formation and surface generation in high-frequency ultrasonic vibration-assisted diamond cutting

Ultrasonic vibration-assisted cutting (UVAC) is regarded as a feasible technology to machine difficult-to-cut materials. High-frequency ultrasonic vibration-assisted cutting (HFUVAC), with a working frequency of more than low and medium frequency (20–60 kHz), has been reported to improve material machinability and prolong tool life. This paper presents a comprehensive investigation of the ultrasonic cutting kinematics and the generated chip/surface formation process in HFUVAC of a 316l stainless steel workpiece. First, the ultrasonic cutting kinematics was analyzed and verified by comparing the experimental and theoretical surface texture under different nominal cutting speeds. Based on the ultrasonic cutting kinematics and the simulated strain/stress distributions, the chip and surface formation between conventional cutting (CC) and HFUVAC was analyzed. More importantly, the incremental cutting mode was defined when the cutting stroke, namely the effective cutting length in one vibration cycle was less than 800 nm. The results show that in the incremental cutting mode, defect-free surface was achieved due to suppressed large deformation and friction action. Finally, HFUVAC of the sinusoidal microstructure was performed under the incremental cutting mode, achieving optical requirements with nanometer-scale surface roughness and submicrometric form accuracy, which validates the technical feasibility in HFUVAC of micro-structured surfaces.

Mechanism of chip segmentation transition from shear slip to shear fracture of Zirconium-based bulk metallic glass in mechanical machining

An in-depth understanding of material cutting deformation forms the foundation for manufacturing Zirconium-based bulk metallic glass (Zr-based BMG) parts. This study explores the transition in chip segmentation mode from shear slip to shear fracture in Zr-based BMG during mechanical machining. The investigation covers chip micromorphology, cyclic cutting force, machined surface quality, and the themo-mechanical properties under various chip segmentation modes linked to cutting conditions. A size-dependent transition in chip segmentation has been observed in the cutting of Zr-based BMG. At a specific cutting speed, a smaller uncut chip thickness favors chip formation via shear slip, resulting in a smooth primary shear zone (PSZ). Conversely, a larger uncut chip thickness leads to chip shear fracture, with the PSZ displaying fishbone-like and dimple patterns. The integration of the modified cutting kinematic model with the free volume-dependent shear transformation zone (STZ) model suggests that the transition from shear slip to fracture is due to an increase in uncut chip thickness, which causes a greater STZ volume in the PSZ. When the STZ volume surpasses a threshold, the intrinsic structural recovery of material from shearing cannot fully compensate for the free volume softening, leading to excessive free volume that ultimately triggers shear fracture. During the chip shear fracture process, the evolution from fishbone-like patterns to dimples in the PSZ is attributed to faster crack propagation at greater uncut chip thickness or higher cutting speeds. In practical applications, it is advisable to avoid chip shear fracture during machining to maintain high-quality machined surface quality.

Comparative effects of pectin and hydrolyzed pectin coating as pre-frying treatments on acrylamide formation in potato chips

This study aimed to compare the effects of pectin and hydrolyzed pectin coating as pre-frying treatments on acrylamide content and quality characteristics of fried potato chips. The hydrolyzed pectin with molecular weight (Mw) of 8.81 ± 0.49 kDa was obtained through partial degradation of pectin (Mw: 747.57 ± 6.73 kDa) using pectinase. Results showed that both pectin and hydrolyzed pectin coating significantly inhibited acrylamide formation and inhibition rates exceeded 90 %. Hydrolyzed pectin had stronger inhibitory activity against acrylamide formation than pectin, especially when the concentration of hydrolyzed pectin was >2 %, its inhibitory rate exceeded 95 %. Compared to pectin coating, hydrolyzed pectin coating endow fried potato chips with smaller browning, higher crispness, less moisture but higher oil content. Overall, hydrolyzed pectin had better application prospects than pectin in inhibiting acrylamide formation of fried potato chips.

Improving Maraging Steel 350 Machinability via Wiper Insert-Enhanced Face Milling

Despite the prevalent application of 18% Ni maraging steel in critical sectors such as aerospace and automotive due to its unique characteristics, including high ductility, yield strength, and hardenability, its machining presents enormous challenges, categorizing it as a difficult-to-machine material. The cutting tool’s geometry is crucial in machining, significantly affecting chip formation, cutting forces, power consumption, and obtainable surface quality. In particular, wiper insert technology, characterized by its multi-radius design, offers an increased contact area compared to conventional inserts, potentially enhancing the quality of the machined surface. This study explores the effectiveness of wiper inserts in the face-milling of maraging steel 350, conducting a comparative analysis across three distinct machining setups. These setups vary by alternating the number of wiper and conventional inserts within the same cutter, thereby examining the influence of insert configuration on machining outcomes. The research employs a reliable and well-established statistical approach to evaluate how different variables, such as cutting speed and feed rate, affect surface quality, power consumption, and material removal rate (MRR). It also sheds light on the material removal mechanisms facilitated by each type of insert. The findings reveal that incorporating a higher number of wiper inserts significantly enhances the surface finish but concurrently increases power consumption. Thus, the study successfully identifies an optimal set of process parameters that attain a balance between achieving superior surface quality and maintaining energy efficiency in the machining of maraging steel 350. This balance is crucial for optimizing manufacturing processes while adhering to the stringent quality and sustainability standards required in aerospace and automotive manufacturing.

Diamond machining of additively manufactured Ti6Al4V ELI: Newer mode of material removal challenging the current simulation tools

Single point diamond machining (SPDM) produces smooth machined surfaces that other production methods cannot match. While the mechanics of machining of cast alloys with SPDM is well-explored, the realm of SPDM for additively manufactured parts remains largely uncharted. This work reveals new insights into the surface generation process of an additively manufactured titanium alloy, specifically, a Ti6Al4V Extra Low Interstitials (ELI) alloy workpiece. Our examination of the chip morphology unveiled a distinct mode of chip removal, previously unrecorded in existing literature. During SPDM of additively made Ti6Al4V ELI workpiece, identification of numerous pores and discontinuities in the chips flowing on the tool rake face, indicating periodic intermittent cracking during the material's plastic flow was seen. To examine this phenomenon, a finite element analysis (FEA) model was developed. While the FEA model can well explain the machining mechanics and chip morphology of SPDM of cast Ti6Al4V ELI reported in the literature, it failed to describe the chip morphology that are obtained during machining of additively made workpiece in this work. This disparity underscores the need for innovative simulation approaches tailored for additively manufactured components. The experimental observations in this study highlight a unique form of chip formation in contrast to conventional Ti6Al4V alloy machining processes. At lower feeds, there was a presence of short, discontinuous chip formation with tearing at the outer periphery. Conversely, at higher feeds, a long, continuous ribbon-like chip formation was observed. In addition, some typical additive manufacturing defects appear on the machined surface and chips. Through optimisation of the SPDT parameters, a surface roughness (Ra) value of about 11.8 nm was achieved on additively manufactured Ti6Al4V ELI workpiece. This work provides a fresh perspective on the mechanics of SPDM for additively manufactured components, offering a stepping stone for subsequent studies.

Non-destructive measurement of MUCT in micro-milling using surface topography generated by bi-planer size effects

In mechanical micro-cutting, a Minimum Undeformed Chip Thickness (MUCT) is desired to ensure chip formation by the round-edged tool. Although the MUCT controls several machinability, productivity, and sustainability attributes, its measurement using output responses is a challenging task. This article, for the first time, demonstrates a non-destructive methodology to measure MUCT in micro-milling using the topographical pattern that inherently remains embedded on the micro-milled floor surface in the form of a microscopic step at the ploughing-shearing transition boundary. Simultaneous action of two Size Effect phenomena that occur concurrently in two mutually perpendicular planes owing to rounded-nose and rounded-edge produce microscopic step during surface generation. A methodology to quantify MUCT using this inconsistent surface topography is also demonstrated. MUCT remains within 36–41 % of the edge radius during dry micro-milling of Ti-6Al-4V using TiAlN-coated WC-6Co tool. The same reduces to 33–40 % of the edge radius when cutting fluid is delivered through sustainable Minimum Quantity Lubrication (MQL) strategy. Proportionality between MUCT and edge radius remains valid during abrasive wear regime of the cutting tool. Tool wear significantly deteriorates surface quality, causing Ra roughness to increase from 40 to 350 nm when adhesion deposits on cutting edge. Consequently, the proposed surface-dependent methodology fails to provide precise MUCT data when cutting tool experiences aggressive wear.

On machining-induced surface integrity of Inconel 718 fabricated by powder bed fusion

Additive manufacturing (AM) introduces unique grain feature and anisotropy in metals, as well as relatively poor surface quality, so the knowledge about the formation of post-machining-induced surface integrity needs to be extended. This study aims to understand the machining phenomena in orthogonal cutting of Inconel 718 produced via powder bed fusion of metals using a laser beam system (PBF-LB/M), paying particular attention to the cutting energy, chip formation, geometrical defects, and microstructural deformation. Experiments are conducted on both wrought (W 718) and PBF-LB/M (PBF 718) Inconel 718, whereby the cutting speed and the anisotropy of the workpiece in the raw state play an important role. The results indicate that less cutting energy is consumed when cutting PBF 718 in the direction perpendicular to its build direction (BD), followed by cutting in its BD. Denser shearing-induced slip lines and relatively continuous chip morphology are found when cutting PBF 718 in its BD, moreover, the effect of cutting speed on shearing deformation of columnar grains under this condition is analysed. More importantly, this study identifies a significant geometrical defect phenomenon which is unique to PBF 718 and highly depends on the cutting speed and anisotropy of grain feature. A detailed characterisation shows that this behaviour is caused by tearing within the grains in the matrix material and not by the presence of hard inclusions, which has rarely been reported in the literature. The microstructure in the subsurface area exhibits that the density of grain boundaries in the cutting direction plays the key role in plastic deformation, as the machining process mainly causes dragging behaviour in the area below the machined surface. Thus, cutting PBF 718 in the direction perpendicular to its BD shows similar deformation layer to W 718, while cutting PBF 718 in its BD displays much stronger subsurface deformation. The obtained results greatly help to understand the cutting phenomena in post-machining of additively manufactured Ni-based components, especially the integrity for a better functional surface.

A framework to efficiently simulate the cyclic variation of the residual stresses induced by chip formation in machining of Ti-6Al-4 V alloy

Residual stresses is a key part of surface integrity, having a strong influence on the functional performance and lifespan of components. Advances in modeling of machining-induced residual stresses are fundamental to achieve more accurate predictions. Due to the low computational efficiency and the lack of consideration of the whole residual stress formation process, a framework to simulate the residual stress in the machining of Ti-6Al-4 V titanium alloy using CEL (Coupled Eulerian and Lagrangian) and Lagrangian approaches is proposed. A model of the cutting and workpiece unloading processes is simulated using CEL approach and explicit time integration scheme. Then, a model of the cooling process of the workpiece is developed in order to calculate the residual stresses. To improve computation efficiency and to reduce the effects of cumulative errors, this model is simulated using Lagrangian approach and implicit time integration scheme. Data transfer between these two models is performed by combining a strategy of data transfer and mesh rebuilding. The cutting force and residual stress are obtained by simulation with average errors of 18% and 21%, respectively. The predicted and measured thicknesses of the layer are reasonable well predicted. The computational time of proposed approach can be greatly reduced from 81 h to 5.3 h by comparison with traditional one. This framework was then used to investigate the cyclic variation of the residual stress along the cutting direction, which is due to the cyclic nature of the chip formation process.

Understanding the Relationship between Surface Quality and Chip Morphology under Sustainable Cutting Environments.

Although chip morphology changes according to the machining method and related cutting parameters, chip formation affects the quality of the machined surface. In this context, it is very important to understand the relationship between chip morphology and surface quality, especially in materials that are difficult to machine. In the presented study, the changes in chip morphology, surface morphology, and surface quality criteria (Ra and Rz) that occurred during the milling of precipitation-hardened steel in different cutting environments were analyzed. Milling experiments were carried out in dry, MQL (minimum quantity lubrication), nano-MQL (graphene), nano-MQL (hBN), Cryo, and Cryo-MQL environments using TiAlN-coated inserts and three different cutting speeds and feed rates. While the highest values in terms of Ra and Rz were measured in dry machining, the minimum values were obtained in a nano-MQL (hBN) cutting environment. Due to the lubrication and low friction provided by the MQL cutting environment, chips were formed in thinner segmented forms. This formation reduced the chip curve radius and thus provided a more stable surface morphology. On the other hand, Cryo-ambient gas could not effectively leak into the cutting zone due to the intermittent cutting process, but it increased the brittleness of the chips with the cooling effect and provided a similar surface morphology. The values of minimum Ra and Rz were obtained as 0.304 mm and 1.825 mm, respectively, at a 60 m/min cutting speed and 0.04 mm/rev feed. Consequently, the use of nano-MQL cutting medium is seriously recommended in terms of surface quality in milling operations of difficult-to-machine materials.

Frictional behaviour of coated carbide tools and AISI 316L when using translational and rotatory relative movement considering dry and lubricated conditions

In machining, tool temperatures and thus tool wear are significantly influenced by frictional behaviour. Friction tests are used to determine the friction coefficient depending on relative speed, which serves as basis for parameterising friction models as input data for chip formation simulations. Therefore, this paper represents investigations towards the frictional behaviour of uncoated and coated (TiN, TiAlN) carbide tools when using two different relative movements (translational and rotary) and cooling lubricant conditions. In dry conditions, the investigations show insignificant influence of different engagement surfaces and testing kinematics on resulting friction. In lubricated conditions, three different friction coefficient sections were observed.

Cryogenic and ultrasonic-assisted micro-drilling of printed circuit boards using high-frequency-amplitude spindle

Printed circuit boards (PCBs) are key components in computers, 5G, 6G, and other wireless communication devices. On the other hand, the manufacture of micro-holes in PCBs faces severe challenges. Conventional micro-drilling methods often encounter challenges such as poor surface quality and limited tool life. To overcome these issues, a novel micro-drilling method called cryogenic and ultrasonic-assisted micro-drilling (CUAMD) has been developed. This study compared four drilling methods to investigate the benefits of cryogenic and ultrasonic-assisted drilling in hybrid machining processes: conventional micro-drilling (CMD), cryogenic-assisted micro-drilling (CAMD), ultrasonic-assisted micro-drilling (UAMD), and cryogenic and ultrasonic-assisted micro-drilling (CUAMD). The experimental results unequivocally indicate that the utilization of cryogenic-assisted drilling leads to a significant reduction in cutting heat during the machining process. This not only contributes to an improvement in machining accuracy but also exerts a positive influence on tool life and surface morphology. Ultrasonic-assisted drilling separates chips into smaller volumes through high-frequency-vibration, effectively reducing the cutting forces. The high frequency of 38.25 kHz and high amplitude vibration of 5.16 μm of the ultrasonic spindle induced vibrations on the drill bit. Liquid nitrogen with a pressure and temperature of 28 kPa and − 196 °C, respectively, was used in the cryogenic-assisted method. The superior machining performance of the CUAMD approach was evaluated by comparing it to various methods, including cutting forces, tool flank wear, entrance/exit hole morphology, and chip formation. The CUAMD method avoids chip entanglement, suppresses burrs, and reduces the maximum cutting force, maximum torque, and exit hole damage factor Fd by 47.7 %, 56.1 %, and 42.5 %, respectively, compared with CMD.

Application of 3D Imaging for Analyzing the Chip Groove Shapes of Cutting Inserts

An effective chip formation process is significant for an efficient metal-cutting process. Long continuous chips can lead to scratches on the machined surface, increasing the risk to operator safety and stability of the machining process. The use of chip grooves on cutting inserts allows for control of the chip formation and breaking process during machining. The shape of the rake surface and the design of the chip groove also affect the efficiency of the machining process. The article presents the use of 3D imaging to analyze changes in the selected chip groove shapes depending on the cutting depth ap = 0.10, 0.25, and 0.50 mm and the angular location of the cutting insert relative to the machined surface of the workpiece (i.e., major cutting-edge angle K = 60° and K = 90°). The analysis methodology was based on the use of 3D image registration and surface shape modeling. In the analysis based on the 3D imaging presented, the novelty was the adaptation of methods typically used to map and model the terrain surface, which have not been used previously in cutting processes. The evaluation of the shape of the chip groove surface was carried out using, e.g., watershed maps and 3D surface maps. The obtained results indicated a significant influence of the cutting depth and major cutting-edge angle on the surface shape, profile, and length of the chip former; chip groove volume; and the theoretical contact area of the formed chip with the cutting insert. It was observed that for small depths of cut, i.e., ap < 0.25 mm, the chip-curling process may be difficult due to the flattened shape of the rake surface. In addition, the influence of the convexity of the rake surface of the cutting insert on the chip formation process was demonstrated. The results of the experimental research that verified the conclusions are presented. The developed results may be useful in the process of selecting the parameters and conditions of the metal finishing through use of tools with a shaped rake surface.

Prediction of tool-chip contact length based on slip-line modeling of orthogonal cutting with rounded-edge cutting tools

It is known that no cutting tool has a perfectly sharp cutting edge and that there is always a small rounding on the cutting edge of the tool. In this study, a new tool-chip contact length equation is presented for cutting tools with rounded-edge in orthogonal cutting. This equation was obtained based on a newly developed slip-line model. This newly developed slip-line model has rounded-edge cutting and considers the presence of a dead metal zone in front of the cutting edge. To verify the newly developed tool-chip contact length equation, experimental studies were conducted at various cutting speeds and uncut chip thickness values at both 0° and 6° rake angles, using cutting tools with 50 μm–100 μm–150 μm edge radii. Orthogonal cutting experiments were carried out using the shaping-based quick stop device and brass (CuZn30) material was chosen as a workpiece that allows continuous chip formation without built-up edge. Strong correlation was observed between the experiment results and values that were obtained from the newly developed tool-chip contact length equation.

Chip Formation and Shaping in Milling Machining of Light Metal Casting Materials

The main purpose of the research is to study the floating chips produced during mechanical processing. Chips derived from aluminium material cause several difficulties in mechanical processing. Research shows that floating chips clog filters in chip conveyors, resulting in significant downtime in production processes. In this article, cause-effect research has been carried out to find approaches to solving this problem.

The residual stress state in meso- and micro-milling processes with a ball-end mill in Ti–6Al–4V titanium alloy

An experimental investigation and comparative analysis of the residual stress state between micro- and meso-milling processes with a ball-end mill on the Ti–6Al–4V titanium alloy were carried out. A methodology to study the characteristic kinematics of a five‑axis machining process in a three-axis vertical machining centre was proposed. The study considers the chip formation process according to the lead and tilt angles of the tool axis concerning the normal vector of the surface. When using the up‑milling cutting strategy, the defect of smeared/adhered material to the surface occurs in both the micro- and meso-milling levels, associated with the build-up edge and build-up layer phenomenon. The residual stress tensor of the surface was obtained through the X-ray diffraction technique. The down-milling cutting strategy produced the best surface finish and higher compressive residual stresses. The experiments showed higher compressive residual stresses in the feed direction than in the cross-feed direction. The micro-milling process produced higher compressive residual stresses than those observed in the meso-milling process.

Investigation of friction modeling on numerical Ti6Al4V cutting simulations

Friction significantly influences chip formation, thereby highlighting its modeling critical in numerical cutting simulations. Notably, issues like the underestimation of feed force in simulations are often attributed to inadequate friction models. Nevertheless, diverse conclusions in the literature regarding friction’s behavior complicate the accurate implementation of this input. Additionally, the enormous number of the available friction models and their varied calibration methods introduce further debates over which aspects of friction modeling should receive more focus. These controversies and deficiencies hinder progress in further understanding friction’s role in chip formation through numerical studies. Instead of proposing or calibrating new friction models, the current study, based on Ti6Al4V machining simulations, attempts to readdress the aforementioned controversies in a neutral stance by conducting sensitivity studies using a hybrid Smoothed Particle Hydrodynamics (SPH) - Finite Element Method (FEM) solver with Graphics Processing Units (GPU) acceleration, which is capable of efficiently executing high-resolution computations. The significant impact of friction particularly at the end of the tool-chip contact on the chip formation, physical contact states and process forces are highlighted. The behaviors of physical parameters including normal contact pressure, sliding velocity, and temperature-dependent friction models in the literature are also evaluated. Several aspects such as the shear flow stress limit, the relationship between friction and process forces, and the selection of different models are discussed. In conclusion, pragmatic recommendations for friction modeling and cutting simulation work are provided. On the one hand, the available complex physical parameter dependent friction models could not prove their necessity and should be approached cautiously. Instead, the constant Coulomb friction model without the shear stress limit, despite its simplicity, demonstrates effective and sufficient for a single set of metal cutting simulations. On the other hand, reliable on-site measurement techniques of the coefficient of friction (COF) at the tool-chip sliding contact area should be developed, with consideration of the contact length and the state of material flow. Combined with careful cutting edge preparation and suitable constitutive models, the overall accuracy of numerical cutting simulations including the feed force prediction is expected to be improved.

Grinding performance investigation of multidirectional CF/PEEK composites—A comparative with unidirectional CF/PEEK

AbstractTo distinguish the grinding performance of the multidirectional (MD) and unidirectional (UD) carbon fiber‐reinforced thermoplastic (CFRTP) composites, MD and UD carbon fiber‐reinforced poly‐etherether‐ketone (CF/PEEK) composites were employed in this study. Different ply stacking sequences and process parameters were set for grinding experiments. Subsequently, the surface morphologies and roughness were observed and measured. Experimental results indicated that the variations of grinding forces with grinding parameters of MD‐CF/PEEK and UD‐CF/PEEK were consistent. However, the heat transfer mechanism and the effects of grinding parameters on the maximum grinding temperatures were different between the two composites. The grinding forces and temperatures of MD‐CF/PEEK were slightly lower than UD‐CF/PEEK, and MD‐CF/PEEK reached better surface quality under the same parameters, indicating that the grinding performance of MD‐CF/PEEK was not the simple superposition of UD‐CF/PEEK. In addition, the chip formation and material removal mechanism of CF/PEEK were investigated. The grinding performance of MD‐CF/PEEK was primarily dependent on the θ elements of laminate while the grinding performance of UD‐CF/PEEK was closely related to the fiber orientation angles during grinding. This study established a more in‐depth understanding into the grinding performance of MD‐CF/PEEK and provided technical guidance for high‐quality grinding of CFRTP.Highlights The grinding performance of the multidirectional (MD) and unidirectional (UD) carbon fiber‐reinforced poly‐etherether‐ketone (CF/PEEK) is compared. The grinding forces and temperatures of MD‐CF/PEEK are slightly lower than that of UD‐CF/PEEK, and the MD‐CF/PEEK reach a better surface quality under the same grinding parameters. The grinding performance of MD‐CF/PEEK is primarily dependent on the θ elements of laminate, and the change of layering order is not a critical factor. The grinding performance of UD‐CF/PEEK is closely related to the fiber orientation angles during the grinding process. The surface quality of MD‐CFRTP can be effectively improved by reducing the grinding depth and feed speed, and increasing the grinding wheel speed.

Parametric evaluation of chip formation in peripheral milling of single crystal Ni-based superalloy

Parametric evaluation of chip formation in peripheral milling of single crystal Ni-based superalloy