Search

Continuous research in the field of metal additive manufacturing has led to the need for constant improvement of manufacturing parameters especially in the case of FDM (Fused Deposition Modeling) manufacturing. In recent years, the main directions outlined for productivity and quality improvement were related to higher printing speed and the use of ironing-type processes. This article aims to study the manufacturing parameters of the dimensional accuracy and surface quality of FDM-manufactured 316L stainless steel. The degree of novelty is given by the application of the ironing process for the green part. A full factorial 33 experimental design was designed for this study, in which the factors studied were ironing angle, ironing speed, and layer spacing during ironing. The dimensional accuracy and surface roughness were analyzed by means of deviation measurement from CAD to the green part and final part after the sintering process. Using the design of experiments offers the possibility of applying the analysis of variance (ANOVA) which provides information about the degree of influence of each of the studied factors. The results obtained for the dimensional accuracy showed that the ironing direction had the biggest influence on the Z-axis shrinkage. Overall, approximately 6% shrinkage in the Z and Y directions was obtained while in the X directions, the shrinkage percentage was around 20%. Surface roughness showed an improvement with higher ironing speeds for the green part while for the sintered part the most significant factor was ironing spacing. [ABSTRACT FROM AUTHOR]

B4C particle-reinforced Al matrix composite (B4Cp/Al) has excellent properties and is expected to become the mainstream of composites in the future. Due to the complex meso-structure of B4Cp/Al, this increases the difficulty of material precision machining. In addition, the current research on the PRMMCs generally focuses on SiCp/Al and the effects of machining parameters on cutting force and temperature, while the research on the effects of tool geometry parameters on material cutting is relatively rare. Therefore, the cutting mechanism of B4Cp/Al is studied by finite element simulation. Firstly, based on the meso-structure of B4Cp/Al, a three-dimensional (3D) model of the material is established. Then the mechanism of surface formation of B4Cp/Al was studied by combining cutting simulation and turning experiment. Use the simulation to study the effect of tool rake angle on material cutting surface quality. It was found that the removal mode of B4C particles, the residual stress in Al matrix after cutting, and the plastic deformation would be affected by the tool rake angle, thus affecting the cutting surface quality. After a comprehensive comparison, it is found that when the rake angle is − 5°, the cutting quality is the best. [ABSTRACT FROM AUTHOR]

Severe tool wear significantly impacts both the tool life and machined surface quality when machining difficult-to-cut materials. Sufficient cooling and lubrication capacity provided by cutting fluid can effectively mitigate tool wear, whereas conventional flood cooling methods consume excessive amounts of cutting fluid, raising serious environmental concerns. The atomization mode of cutting fluid is accompanied by a minimum quantity of cutting fluid, and it has demonstrated exceptional cooling and lubrication performance for machining difficult-to-cut materials. In this work, various sustainable cooling conditions were employed, including dry cutting, high-pressure air cooling (HPAC), air atomization of cutting fluid (AACF), and ultrasonic atomization of cutting fluid (UACF). A series of experiments were implemented to investigate the tool wear behavior during the milling process of ultra-high-strength steel under different cooling conditions. The effects of tool wear evolution on the milling force, surface quality, and chip morphology were thoroughly analyzed. Results showed that micro-chipping, macro-chipping, and breakage were the primary wear evolution forms of the tool in HPAC condition, while the tools experienced abrasion, chipping, and breakage in the dry, AACF, and UACF processes. The occurrence of severe tool wear, leading to poor surface quality and chip tearing, was observed as the maximum flank wear width VBmax exceeded 0.2 mm. Compared to other cooling conditions, the UACF process exhibited the lowest tool wear and resultant milling force, as well as the best surface quality, attributed to the exceptional cooling and lubrication performance of droplets generated through ultrasonic atomization. [ABSTRACT FROM AUTHOR]

Nanomaterials are used in a variety of fields. As a novel way to produce nanofibers, high-speed centrifugal spinning has attracted wide attention. Nanofibers are widely used in medical transmission, bio-chips, and environmental protection. In high-speed centrifugal spinning production, the quality of nanofibers will be affected by the coupling effects of gravity field, centrifugal position, flow field, temperature and humidity field. The quality of nanofibers will also be affected by the collection distance, motor speed and nozzle structure size. In this paper, the flow of spinning solution in the nozzle is investigated mathematically. Then the solution flow in the nozzle is simulated. Finally, high-speed centrifugal spinning experiments were carried out and nanofiber membranes were collected. The surface quality of the nanofiber membrane was observed by scanning electron microscope (SEM), and the figure of fiber diameter distribution was obtained. Thermogravimetric (TG) analysis shows that the thermal stability and ablative resistance of nanofiber membranes are improved. The results show that the high-speed centrifugal spinning method has high production efficiency. The nanofibers produced by high-speed centrifugal spinning method have good surface quality, uniform diameter distribution and good thermal stability. [ABSTRACT FROM AUTHOR]

As one of the lightest metals in the world, magnesium alloy can be used to reduce weight and save energy. Magnesium alloy tubes with different shapes can also further direct the transportation of fluid in this light weight. But the tee joint tube is difficult formed because of the complex shapes. In this paper, magnesium alloy tube is applied to form tee joint tube with sand mandrel. During the deformation, the magnesium alloy tube is driven by the sand mandrel pressed by the push. Different from traditional extruding with full tubes without hole on the sidewall, some tube with holes on the sidewalls are also used in the extrusion. All the key parameters such as extrusion depth, temperature, tube length, hole size, and hole location are discussed in both simulations and experiments. After the extrusion results are obtained, the microhardness and microstructures are observed to explain the promotion of the mechanical properties. Based on the results received from both simulations and experiments, deeper extrusion depth, higher temperature, shorter length of tube, larger size of the hole, and the higher location of the hole influence positively on forming results. No matter there are holes or not on the sidewalls, the errors between the results in simulation and experiment are small. Also the simulation and experiment results can be used to investigate the shape of tee joint tubes. The surface quality can be also measured to prove the surfaces in extrusion with sand mandrel acceptable. A novel strategy to sand mandrel extrusion of magnesium alloy tee joint tube by tube with holes on sidewall is provided. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced ceramic matrix composites have excellent heat resistance and wear resistance, making them extensively utilized in the aviation and aerospace industries. However, processing carbon ceramics is challenging due to the inherent difficulty. Traditional hole-making methods often result in issues such as delamination and tearing during the processing of carbon ceramics. Helical grinding has emerged as a novel processing technology that shows promise for difficult materials like carbon ceramics. To address the lack of clarity regarding the removal mechanism and formation mechanism of material damage during helical grinding of carbon ceramic materials, firstly, this study models the trajectory and maximum undeformed chip thickness for a single abrasive. Subsequently, this study analyzes the influence of fiber anisotropy on the removal mechanism during helical grinding of carbon ceramics. The study also investigates the mechanisms behind exit damage occurring during carbon ceramic helical grinding processes. Finally, this study examines helical grinding technological parameters that affect surface quality by analyzing their impact on undeformed chip thickness. The results indicate that the matrix occurs brittle fracture during helical grinding. Four typical removal mechanisms emerge for different fiber angles: debonding is predominant at 0°; fiber fracture occurs at 45°; fiber shear occurs at 90°; fiber pull-out occurs at 135°. Hole exit damage is influenced by fiber direction with minimal damage observed when shear fracture occurs at angles 45° and 90° while burrs phenomenon and tear phenomenon are prevalent at angles 0°and 135°, respectively. By increasing orbital rotation speed and spindle speed or decreasing feed pitch, surface quality improved. Grinding parameters significantly affect surface quality by changing undeformed chip thickness and surface residual height. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced thermoplastic (CFRTP) composites, known for their excellent mechanical properties and environmental sustainability, are highly sought‐after in aerospace, energy, and many other fields. Grinding could be used to realize the high‐accuracy and low‐damage machining of CFRTP components. However, due to the temperature sensitivity and water absorption of CFRTP, dry and flood lubrication grinding could cause thermal damage and hygrothermal aging, respectively. In addition, these methods could lead to dust and excessive cutting fluids harmful to the environment. Addressing these bottlenecks, this study is the first to propose using oil‐on‐water minimum quantity lubrication (OoW‐MQL) to grind CFRTP. Experiments including various lubricating conditions and grinding parameters were performed to investigate the grinding performance. Experimental results showed that OoW‐MQL with the oil–water proportion of 1:1 outperformed the other lubricating conditions, achieving the best surface quality with the lowest grinding forces and temperatures. The optimal oil–water proportion remained almost unchanged under different grinding parameters. Furthermore, importance analysis using the extreme gradient boosting (XGBoost) algorithm demonstrated that oil–water proportion was the most critical factor affecting surface roughness. This study proves the feasibility of OoW‐MQL and provides technical guidance for high‐quality grinding of CFRTP. Highlights: Oil‐on‐water minimum quantity lubrication (OoW‐MQL) was proposed to grind carbon fiber reinforced thermoplastic (CFRTP) composites.The experimental results of grinding forces, grinding temperatures, surface roughness and surface morphologies were analyzed, which proved that OoW‐MQL with oil–water proportion (1,1) had outstanding lubricating and cooling capability.The effect of grinding parameters on the optimal oil–water proportion was proved to be negligible through comparative tests under grinding parameters of high force and high temperature.Quantitative analysis using the extreme gradient boosting (XGBoost) algorithm identified the oil–water proportion as the most critical factor influencing surface roughness. [ABSTRACT FROM AUTHOR]

Polyethersulfone (PES) is distinguished by its exceptional comprehensive properties, making it a highly valued engineering plastic employed in various cutting‐edge fields. However, the high cost of PES limits its wider application in industrial fields. Considering the cost‐reduction advantages of polymer foaming, PES foams were successfully prepared in this work using microcellular injection molding (MIM) and micro‐opening microcellular injection molding (MOMIM) foaming methods. Compared with the MIM foaming method, the PES foam samples prepared by the MOMIM foaming method have better microcellular structure and surface quality. As the micro‐opening distance increased, the cell density of the PES foam samples showed a gradual rise before plateauing, with the cell size remaining relatively constant. As a result, the density of the PES foam sample dropped to 1.07 g/cm3, which is 80.5% of the solid PES sample. Meanwhile, the mechanical properties of the PES foam samples remained robust, with both the specific flexural modulus and the specific flexural strength showing increases as the micro‐opening distance increased. The knowledge obtained from this study provides a method for preparing high‐performance PES foam materials, which will facilitate the application of PES in more civilian fields. [ABSTRACT FROM AUTHOR]

In this paper, a theoretical model for the grinding force of SiCp/Al composites was established. The model introduces a novel approach by integrating the SiC particle fracture force, the arc length of contact between the grinding wheel and workpiece, and the maximum undeformed chip thickness, all grounded in the principles of chip formation and friction forces. The accuracy of the grinding force theoretical model was validated through grinding experiments. Additionally, the effects of machining parameters and grinding wheel types on grinding force, surface roughness, and surface morphology were further investigated. The results indicate that as the grinding depth and feed speed increase, both the grinding force and surface roughness increase, resulting in poorer material surface quality. Conversely, when the grinding wheel speed increases, both the grinding force and surface roughness decrease, leading to better material surface quality. Compared to using electroplated diamond wheels, the use of resin bond wheel results in lower grinding force, lower surface roughness, and improved surface morphology, which proves that resin bond wheel has better grinding performance when grinding SiCp/Al composites with SiC volume fraction of 20%. This study indicates that the research facilitates the calculation of grinding forces in actual machining processes, as well as the selection of grinding parameters and types of grinding wheels. [ABSTRACT FROM AUTHOR]

This research aims to enhance the surface quality, mechanical properties, and biocompatibility of PEEK (polyether–ether–ketone) biomimetic dental implants through laser polishing. The objective is to improve osseointegration and implant durability by reducing surface roughness, increasing hydrophilicity, and enhancing mechanical strength. The methodology involved fabricating PEEK implants via FDM and applying laser polishing. The significant findings showed a 66.7% reduction in surface roughness, Ra reduced from 2.4 µm to 0.8 µm, and a 25.3% improvement in hydrophilicity, water contact angle decreased from 87° to 65°. Mechanical tests revealed a 6.3% increase in tensile strength (96 MPa to 102 MPa) and a 50% improvement in fatigue resistance (100,000 to 150,000 cycles). The strength analysis result showed a 10% increase in stiffness storage modulus from 1400 MPa to 1500 MPa. Error analysis showed a standard deviation of ±3% across all tests. In conclusion, laser polishing significantly improves the surface, mechanical, and biological performance of PEEK implants, making it a promising approach for advancing biomimetic dental implant technology. [ABSTRACT FROM AUTHOR]

The use of carbon fiber reinforced polymers (CFRP) is crucial in industries, such as aerospace, automotive, and marine, due to their excellent strength-to-weight ratio and corrosion resistance. However, machining CFRP is challenging due to its abrasive nature, which can cause premature tool wear. Some of the commonly used processes for machining these materials are dry milling and abrasive water jet machining (AWJM), which offer the best alternatives from an environmental point of view. This article presents an analysis of the defects and surface quality obtained in CFRP after machining by AWJM and milling. For this purpose, combinations of relevant parameters have been chosen for each process: cutting speed and tool wear in milling and traverse feed rate and hydraulic pressure in AWJM. The results obtained have been evaluated from two points of view: macroscopically, through the evaluation of delamination, and microscopically, through the study of the roughness in terms of Ra. Furthermore, a discussion on functional, environmental, economic, and social terms has been made between both processes. In summary, each machining process generates a specific type of delamination: Type II in milling and Type I in AWJM. In addition, the best Ra results are obtained for pressures of 1200 bar in AWJM. [ABSTRACT FROM AUTHOR]

Surface quality represents a critical challenge in additive manufacturing (AM), with surface roughness serving as a key parameter that influences this aspect. In the aerospace industry, the surface roughness of the aviation components is a very important parameter. In this study, a typical Al alloy, AlSi10Mg, was selected to study its surface roughness when using Laser Powder Bed Fusion (LPBF). Two Random Forest (RF) models were established to predict the upper surface roughness of printed samples based on laser power, laser scanning speed, and hatch distance. Through the study, it is found that a two-dimensional (2D) RF model is successful in predicting surface roughness values based on experimental data. The best and minimum surface roughness is 2.98 μm, which is the minimum known without remelting. More than two-thirds of the samples had a surface roughness of less than 7.7 μm. The maximum surface roughness is 11.28 μm. And the coefficient of determination (R2) of the model was 0.9, also suggesting that the surface roughness of 3D-printed Al alloys can be predicted using ML approaches such as the RF model. This study helps to understand the relationship between printing parameters and surface roughness and helps print components with better surface quality. [ABSTRACT FROM AUTHOR]

Cutting fluid can improve the heat dissipation and lubrication in the cutting process and thus increase the machining quality. In this work, a pollution-free alcohol solution was proposed as the cutting fluid in an ultra-precision cutting process to explore green cutting fluids. The scratching experiments were conducted with the alcohol cutting fluid to study its effect on the cutting process. It is found that the use of an alcohol cutting fluid, on average, reduces the tangential and normal force about 27–53%, but exhibits few effects on the friction coefficient in the cutting process. Compared to dry cutting, the alcohol cutting fluid reduces the exposed shear slip steps on the outside surface of the chip, which implies the decreased chip deformation degree of workpiece material in the cutting process. The alcohol cutting fluid can reduce microburrs and decrease the machined surface roughness Ra from 21 nm to 9.9 nm in the ultra-precision turning application on single-crystal copper material. [ABSTRACT FROM AUTHOR]

Hard–brittle materials are widely used in the optics, electronics, and aviation industries, but their high hardness and brittleness make it challenging for traditional processing methods to achieve high efficiency and superior surface quality. This study aims to investigate the application of ultrasonic local resonant grinding to sapphire to improve the efficiency and meet the requirements for the optical window in the surface roughness of the material. The resonant frequency of a piezoelectric ultrasonic vibration system and the vibration amplitude of a grinding head's working face were simulated and tested, respectively. The results of ultrasonic grinding experiments showed that the local resonant system reduced the surface roughness parameter (Ra) of sapphire to 14 nm and improved its surface flatness to 44.2 nm, thus meeting the requirements for the ultra-precision grinding of sapphire. Compared with a conventional resonant system, the surface roughness of the sapphire ground with the local resonant system was reduced by 90.79%, its surface flatness was improved by 81.58%, and the material removal rate was increased by 31.35%. These experimental results showed that ultrasonic local resonant grinding has better effects than those of conventional ultrasonic grinding in improving surface quality and increasing the material removal rate. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present work takes a new look at the high temperature strength of single crystal (SX) Ni‐base superalloys. It compares high temperature constant strain rate (CSR) testing, creep testing, and out‐of‐phase thermomechanical fatigue (OP TMF) testing, which represent key characterization methods supporting alloy development and component design in SX material science and technology. The three types of tests are compared using the same SX alloy, working with precisely oriented <001>‐specimens and considering the same temperature range between 1023 and 1223 K, where climb controlled micro‐creep processes need to be considered. Nevertheless, the three types of tests provide different types of information. CSR testing at imposed strain rates of 3.3 × 10−4 s−1 shows a yield stress anomaly (YSA) with a YSA stress peak at a temperature of 1073 K. This increase of strength with increasing temperature is not observed during constant load creep testing at much lower deformation rates around 10−7 s−1. Creep rates show a usual behavior and increase with increasing temperatures. During OP‐TMF loading, the temperature continuously increases/decreases in the compression/tension part of the mechanical strain‐controlled cycle (±0.5%). At the temperature, where the YSA peak stress temperature is observed, no peculiarities are observed. It is shown that OP‐TMF life is sensitive to surface quality, which is not the case in creep. A smaller number of cycles to failure is observed when reducing the heating rate in the compression/heating part of the mechanical strain‐controlled OP‐TMF cycle. The results are discussed on a microstructural basis, using results from scanning and transmission electron microscopy, and in light of previous work published in the literature. [ABSTRACT FROM AUTHOR]

Hard turning is a dry machining process that is often preferred over conventional grinding to achieve final dimensions on a workpiece that is already in a hardened state. In this study, hard turning process was preferred due to its numerous advantages such as low machining time, low total production cost, better surface integrity and better environmental effect because of elimination of coolant. The hardness of the material being machined can cause significant wear on the cutting insert. This study investigated the effects of TiCN + Al2O3 + TiN coated carbide inserts on the machining process of hardened AISI D2 cold work tool steel. The temperature of cutting zone, tool wear, flank wear, surface roughness, hardness, chip formation, and microstructure were all measured as a function of cutting speed. A real-time monitoring system was used to measure wear at the tool edge and temperature on the flank face of the cutting insert. The results showed that increasing cutting speed from 100 to 157 m/min led to higher cutting edge temperatures (from 585 to 713°C, respectively) and lower tool flank wear (from 14.6 to 10.8µm, respectively). The multilayer coated carbide inserts produced a ground-quality surface finish with a roughness value of 0.10–0.15 μm. Achieving high cutting edge temperature, low tool flank wear and fine-grinding quality surface finish underscore the effectiveness of using multilayer-coated carbide inserts in the hard turning of hardened steels. [ABSTRACT FROM AUTHOR]

This study presents an innovative approach to predicting the quality of finished parts in top milling processes by integrating robust parameter design with artificial intelligence techniques. A central composite design was used to combine controllable variables (cutting speed, tooth advance, milled width, and cutting depth) with noise variables (tool flank wear, fluid flow, and cantilevered length). Duplex stainless steel was milled under each experimental setup, and roughness data were collected. These data were used to train three machine learning models: random forest, decision tree, and support vector machine. The models predicted surface roughness, and their predictions were validated through experimental tests. The root means square error values were 0.031 for the random forest, 0.038 for the decision tree, and 0.066 for the support vector machine, indicating that the random forest model performed the best. This innovative study highlights the importance of including noise variables along with controllable factors in machine learning models, significantly improving prediction accuracy and making them more reflective of real-world results. Including these variables is crucial, as neglecting them can lead to inaccurate predictions. [ABSTRACT FROM AUTHOR]

Soft-brittle crystals such as KH2PO4 (KDP) pose significant challenges to traditional machining techniques due to their inherent brittleness and substantial sizes. To surmount these challenges, this paper presents the water dissolution combined continuous polishing (WDCCP) method based on the water dissolution principle for achieving high-efficiency and high-quality machining. The WDCCP process is a three-step methodology including initial precision polishing with an aqueous solution, subsequent ultra-precision polishing utilizing a water-in-oil microemulsion, and final cleaning with anhydrous ethanol. Comprehensive analyses of the slurry's microstructure and viscosity are conducted to reveal the surface planarization mechanism. Multiple slurry dispensers ensure a more uniform distribution of various slurries across the interface between the KDP crystal and the pad, thereby enhancing surface quality. Experimental trials conducted on a large numerical control polishing machine demonstrate that precision polishing can eliminate sawn surface defects within a mere 5 min. The ultra-precision polishing significantly reduces the surface roughness root mean square (rms) from 474.974 to 2.779 nm and the peak-to-valley (PV) from 29.859 to 48.949 nm. After WDCCP, the integral morphology of a 180 mm × 180 mm KDP crystal exhibits a PV of 1.938 waves and an rms of 0.264 waves. The WDCCP method emerges as a potent and efficient solution for the machining of large-sized soft-brittle crystals. [ABSTRACT FROM AUTHOR]

With the rapid advancement of 3D-printing technology, additive manufacturing using FDM extrusion has emerged as a prominent method in manufacturing. However, it encounters certain limitations, notably in surface quality and dimensional accuracy. Addressing issues related to stability and surface roughness necessitates the integration of 3D-printing technology with traditional machining, a strategy known as the hybrid technique. This paper presents a study of the surface geometric parameters and microstructure of plastic parts produced by FDM. Sleeve-shaped samples were 3D-printed from polyethylene terephthalate glycol material using variable layer heights of 0.1 mm and 0.2 mm and then subjected to the turning process with PVD-coated DCMT11T304 turning inserts using variable cutting parameters. The cutting depth was constant at 0.82 mm. Surface roughness values were correlated with the cutting tool feed rate and the printing layer height applied. The selected specimen's microstructure was studied with a Zeiss EVO MA 15 scanning electron microscope. The roundness was measured with a Keyence VR-6200 3D optical profilometer. The research results confirmed that the additional application of turning, combined with a reduction in the feed rate (0.0506 mm/rev) and the height of the printed layer (0.1 mm), reduced the surface roughness of the sleeve (Ra = 1.94 μm) and increased its geometric accuracy. [ABSTRACT FROM AUTHOR]

To address the challenge of high rejection rates due to surface quality defects that are hard to detect with the naked eye, a comprehensive model was developed for detecting such defects and implemented a full-fledged equipment and system for surface quality inspection. Specifically, a targeted comprehensive model was formulated to identify three types of plate and strip surface quality defects. Furthermore, the latest hardware equipment and an advanced unsupervised self-learning algorithm were integrated into the detection system to enhance the identification and classification of these surface quality defects. The results demonstrate an improvement in the comprehensive detection rate and classification accuracy of surface defects from 96 % and 91 % to 98 % and 95 %, respectively. Moreover, the qualified rate of finished products has increased from 94 % to 99 %, leading to improved accuracy in defect detection and a significant decrease in false alarm rates. These findings provide a solid foundation for significantly reducing material waste and enhancing the overall quality of the production process. [ABSTRACT FROM AUTHOR]

The tool-workpiece vibration in the precision milling process plays a pivotal role in influencing the surface quality. To solve the machining problem coming with the process vibration, the active vibration control model as well as the corresponding platform are developed, and the active vibration control algorithms are applied to reduce the relative vibrations and improve the surface quality. Firstly, the milling vibration reduction and surface quality improvement are modeled based on the active control algorithms and the system dynamic characteristics. Then, applying the different algorithm control strategies, such as PID, Fuzzy PID, BP neural network, and BP neural network PID control, the control effect is simulated and analyzed. Finally, an experimental platform is established to validate the system's reliability. The efficiency of various active control methods is compared in terms of frequency vibration control and surface finish roughness improvement. The results indicate that under different milling parameters, the four algorithm control strategies exhibit optimal effects of 13.5%, 30.4%, 28.8%, and 40.1% respectively. These findings provide valuable insights into selecting the optimal vibration control method for precision milling. [ABSTRACT FROM AUTHOR]

Population growth and economic development are leading to an alarming increase in global energy consumption. Numerically controlled machine tools are widely used in metalworking processes due to their efficiency and ability to achieve high-precision machining. However, the use of simple machining features to determine cutting parameters and the machining process is limited, as parts may contain complex features interacting with each other. This study, therefore, focuses on pocket/groove features and proposes an approach integrating hybrid GA-ANN and RSM algorithms to predict surface quality, cost, and energy consumption (QCE). A parametric study was carried out, taking into account the swarm population size (pop) and the number of neurons (n) in the hidden layer, to find the best prediction using the hybrid GA-ANN algorithm. The results showed the highest correlation values (R2) for all output variables (above 0.97%). The study revealed that modifying machining strategies and sequence planning can significantly decrease energy consumption by as much as 99.25%. Research found that the depth of cut is the most impactful factor on energy use, contributing 60.11%, followed by cost at 46.76%. Additionally, the GA-ANN model demonstrates strong performance in minimizing mean square error (MSE), leading to substantial improvements of 90.91%, 96.55%, and 40.18% in the Etot, Ctot, and Ra parameters when compared to the RSM model. This study highlights the potential of the GA-ANN hybrid approach for multi-criteria prediction (quality, cost, and energy: QCE) in comparison with the RSM method, offering potential improvements for machining 2017A alloy. [ABSTRACT FROM AUTHOR]

Additive/subtractive hybrid manufacturing (ASHM) based on laser powder bed fusion (LPBF) enables to achieve high precision and good surface quality of complex structures such as small holes with overhanging features. However, the rapid heating and cooling rates during the ASHM results in sinkage at the alternating interface of additive manufacturing and subtractive milling, which degrades the surface quality of the components. This study employs shielding height at the alternating interface to solve this problem and improve the surface quality. The effect of internal diameters and shielding heights on the surface quality were studied experimentally for overhanging holes fabricated by ASHM of Ti6Al4V. The results show that the Ti6Al4V samples prepared by LPBF possessed high density and uniformly distributed microstructure. For overhanging holes without shielding height, the largest depth value of sinkage and surface roughness were obtained, indicating a worse surface quality; when the shielding height was increased to 0.5 mm, the smallest sinkage value and surface roughness were obtained, indicating a better surface quality. With the same shielding height, the overhanging holes with different diameters had a similar surface roughness. This study reveals that an appropriate shielding height can improve the surface quality, which provides guidance to the improvement of the surface quality for complex structures in ASHM. [ABSTRACT FROM AUTHOR]

This article presents a review on some important recent research, development, and innovations related to the nonconventional machining of glass material. Nonconventional machining processes were identified suitable for machining of glass, years ago, and from then to now various technological developments have made nonconventional machining a viable alternate to the conventional machining of glass material. In this article, we have mainly focused on three important nonconventional machining processes, namely, last cutting, ultrasonic machining, and electrochemical discharge machining (ECDM). Novel aspects, effects of process parameters, and salient features are discussed. Mainly, previous five years' work is reviewed. This review finally ends with a conclusion and important future research directions. [ABSTRACT FROM AUTHOR]

Abrasive Waterjet (AWJ) milling effectively processes high-strength materials like WNiFe tungsten alloy without altering their properties. This study investigates the effects of jet pressure, traverse speed, and abrasive mass flow rate on the machining performance. The results indicate that increasing jet pressure significantly enhances groove depth, with higher pressures leading to more aggressive material removal. Conversely, higher traverse speeds reduce groove depth, emphasizing the need for slower speeds for deeper penetration. Increased abrasive mass flow rates also significantly improve groove depth but pose challenges related to material wear and cost. Surface analysis using scanning electron microscopy (SEM) revealed that higher jet pressures and lower traverse speeds produce smoother surfaces and more distinct grooves. The findings highlight the importance of optimizing AWJ parameters to achieve efficient material removal and desired groove geometries. This research provides valuable insights for improving AWJ machining of tungsten alloys in industrial applications.

High-strength seismic-resistant rebar is essential in construction engineering, yet balancing its strength, plasticity, seismic resistance, and surface quality poses challenges. This research explores niobium-vanadium-nitrogen composite reinforced steel, examining how cooling bed temperature affects its microstructure, mechanical properties, and surface quality using advanced microscopy techniques. The research reveals that the steel's microstructure primarily consists of ferrite and pearlite. As cooling bed temperatures decrease, both the proportion and colony size of pearlite, along with ferrite size, show a declining trend. Specifically, reducing the cooling bed temperature from 1100 °C to 900 °C results in a decrease in yield strength, tensile strength, and tensile-to-yield strength ratio by 6 MPa, 27 MPa, and 0.03, respectively. Meanwhile, elongation after fracture, total elongation at maximum force, and strength-ductility balance improve by 3.8%, 1.5%, and 1.93%, respectively. At a cooling bed temperature of 1100 °C, significant blistering occurs on the steel surface. Significant blistering at 1100 °C vanishes at 1000 °C and 900 °C, with diminished silicon enrichment in the surface oxide scale. A cooling bed temperature of 1000 °C ± 20 °C is recommended for optimal performance. This study provides a temperature control strategy for the properties of high-strength seismic-resistant rebar rated at 650 MPa and above, contributing valuable insights to the field of advanced construction materials.

ObjectivesPolycrystalline diamond (PCD), as a superhard material with high hardness, high wear resistance, and good impact toughness, has a wide range of applications in fields such as cutting tools for superhard materials. However, due to its high hardness, the precision surface processing of PCD has always been a technical challenge. This paper aims to study the influence of lapping pressure on the surface quality of PCD, particularly focusing on the material removal rate, surface roughness, and changes in surface morphology under high-speed grinding conditions.MethodsThe experiment adopts a single-factor test method, keeping the abrasive particle size W5 of the diamond flat grinding disc and the lapping speed of 43.3 m/s constant, while varying the lapping pressure (from 0.10 MPa to 0.18 MPa) to study its impact on the material removal rate, the surface roughness, and the surface morphology of polycrystalline diamond material. The experimental material is a ϕ13 mm × 2 mm polycrystalline diamond composite sheet with a diamond layer thickness of approximately 1 mm. The experimental apparatus is a high-speed grinding testing machine, which uses an electric spindle to drive the diamond flat grinding disc, with a lapping time of 20 minutes. The lapping process is conducted without the use of coolant to avoid its influence on the experimental results.ResultsThe experimental results indicate that the lapping pressure has a significant impact on the material removal rate of PCD. As the lapping pressure increases from 0.10 MPa to 0.18 MPa, the lapping removal rate increases from 0.005 mg/min to 0.030 mg/min, indicating that an increase in lapping pressure significantly improves material removal efficiency. The influence of lapping pressure on the surface roughness of PCD is also significant. With an increase in lapping pressure, the surface roughness gradually decreases, reducing from a higher value at 0.10 MPa to a lower value at 0.18 MPa, with a roughness Ra reduction of approximately 0.020 μm. The impact of lapping pressure on the surface morphology of PCD is manifested by a reduction in surface defects and an expansion of smooth areas. At lower lapping pressures, the surface exhibits numerous pits, interstitial cracks, and mechanical scratches. As the lapping pressure increases, the number of these defects gradually decrease, and smooth areas gradually expand. Scanning electron microscope observations reveal that an increase in grinding pressure helps reduce defects such as intergranular fractures, minute pits, and mechanical scratches, resulting in a smoother surface.ConclusionsThis paper experimentally studies the influence of lapping pressure on the material removal rate, surface roughness, and surface morphology of PCD, and draws the following conclusions. The lapping removal rate of PCD material significantly increases with an increase in lapping pressure, primarily attributed to the high-frequency collisions and frictional heat between diamond abrasive particles and PCD during the lapping process. An increase in lapping pressure significantly reduces the surface roughness of PCD, primarily benefiting from the decreased cutting depth of abrasive particles and increased actual contact area caused by the increased lapping pressure, and the promotion of surface thermochemical reactions and mechanical thermal removal effects by frictional heat. An increase in lapping pressure leads to a reduction in surface defects, an expansion of smooth areas, smaller mechanical scratches, and a significant improvement in the surface quality of PCD.

Purpose – Surface roughness has a serious impact on the fatigue strength, wear resistance and life of mechanical products. Realizing the evolution of surface quality through theoretical modeling takes a lot of effort. To predict the surface roughness of milling processing, this paper aims to construct a neural network based on deep learning and data augmentation. Design/methodology/approach – This study proposes a method consisting of three steps. Firstly, the machine tool multisource data acquisition platform is established, which combines sensor monitoring with machine tool communication to collect processing signals. Secondly, the feature parameters are extracted to reduce the interference and improve the model generalization ability. Thirdly, for different expectations, the parameters of the deep belief network (DBN) model are optimized by the tent-SSA algorithm to achieve more accurate roughness classification and regression prediction. Findings – The adaptive synthetic sampling (ADASYN) algorithm can improve the classification prediction accuracy of DBN from 80.67% to 94.23%. After the DBN parameters were optimized by Tent-SSA, the roughness prediction accuracy was significantly improved. For the classification model, the prediction accuracy is improved by 5.77% based on ADASYN optimization. For regression models, different objective functions can be set according to production requirements, such as root-mean-square error (RMSE) or MaxAE, and the error is reduced by more than 40% compared to the original model. Originality/value – A roughness prediction model based on multiple monitoring signals is proposed, which reduces the dependence on the acquisition of environmental variables and enhances the model's applicability. Furthermore, with the ADASYN algorithm, the Tent-SSA intelligent optimization algorithm is introduced to optimize the hyperparameters of the DBN model and improve the optimization performance.

Experimental studies of the surface of non-metallic materials have been carried out to determine the roughness parameters of materials such as leather, bone, wood, plastic after processing the surface of materials with a laser beam. To assess the quality of the surface layer of materials, the depth of penetration of laser radiation into the material, the average value of the micro unevenness, and the mean square deviation of the micro unevenness were used. To describe the changes in the values of the micro unevenness, graphs of the correlation of the parameters of the micro unevenness and the modulus of elasticity of the surface of various non-metallic materials were used. Approximating polynomials are used to describe the correlations with the representation in a computer. A regression model is proposed that relates the properties of the material to the magnitude of the micro unevenness. Data on the depth of ablation for wood, bone, leather, plexiglass are presented, graphs of the correlation between the amount of surface micro unevenness and the density of materials, between the amount of surface micro-roughness and the modulus of elasticity of materials, the correlation coefficient between the amount of surface micro unevenness and the ignition temperature of organic materials. The obtained models make it possible to implement the proposed principle of laser processing of non-metallic materials, which consists in measuring the modulus of elasticity of the surface of the material and, based on the measurements obtained, control the modes of laser processing of products. The installation of laser surface treatment of non-metallic materials with the implementation of the principle of control of processing modes depending on the measured values of the modulus of elasticity of the surface of the material is proposed. To measure the elastic modulus of a material, a special sensor is used with indentation of the indenter and computer evaluation of the measurements obtained with the formation of solutions for controlling the modes of laser surface treatment of the material. The experimental results obtained made it possible to manufacture a number of products to ensure a given surface quality of non-metallic materials (a writing device, a gift for the newlyweds). Conducting experiments with changes in the power of laser radiation based on the results of measuring the modulus of elasticity of the surface of non-metallic materials has shown the effectiveness of operational setting of laser operating modes to ensure the quality of the surface of non-metallic materials.

Incremental sheet forming has been largely investigated in the last two decades because of its versatility and cost-effectiveness, which make it viable for manufacturing highly customized parts as well as small- and medium-sized batches. This process allows for reaching greater formability compared to conventional sheet-forming processes. In contrast, it is affected by defects like twisting, which strongly influence the geometric accuracy of the formed parts. These aspects are dramatically accentuated when forming soft materials like thermoplastics. With these premises, the following research aims to investigate the effects of the toolpath strategy on the occurrence of failures and defects in the incremental sheet forming under very severe process conditions. Cone frusta with a fixed wall angle were obtained by thin polycarbonate sheets, imposing four unidirectional helical trajectory-based toolpaths, one traditional, and three stair strategies. The analysis of the forming forces, the evaluation of the worked surfaces, and the monitoring of the defectiveness highlight the advantages of a stair toolpath strategy in terms of reduced twisting and loading and high surface quality, regardless of the lubrication conditions. [ABSTRACT FROM AUTHOR]

Ti6Al4V is a widely used alloy due to its excellent mechanical qualities and resistance to corrosion, which make it fit for automotive, aerospace, defense, and biomedical sectors. Due to its high strength and limited heat conductivity, it is difficult to machine. Both the workpiece's and the electrode's conductivity are important factors that impact the electro-discharge machining (EDM) process. In this case, the machining efficiency is also influenced by the electrode selection. As a result, choosing the right electrode and machining parameters is essential to improving EDM performance on the Ti6Al4V alloy. Research on EDM for Ti6Al4V is limited, with little focus on electrode material selection and shape. The impact of EDM settings on MRR, TWR, and surface roughness is complex, and a comprehensive optimization strategy is needed. Copper electrodes are widely used, but further investigation is needed on EDM's effects on Ti6Al4V's surface properties and surface integrity. Addressing these research gaps will improve the understanding and application of EDM for Ti6Al4V, focusing on parameter optimization, surface integrity, and thermal and mechanical effects. By employing copper tools to optimize four crucial EDM process parameters—peak current, duty cycle, discharge current, and pulse-on time—this research aims to increase surface integrity and machining performance. A comprehensive Taguchi experimental design is used to systematically alter the EDM settings. By optimizing parameters using tolerance intervals and response modelling, the recently developed RAMS-RATMI approach improves the dependability of the EDM process and increases machining efficiency. With the optimized EDM settings, there were notable gains in depth of cut enhancement, surface roughness minimization, tool wear rate (TWR) reduction, and material removal rate (MRR). The results of the surface integrity examination showed fewer heat-affected zones, fewer microcracks, and a thinner recast layer. Analysis of variance was used to verify the impact and resilience of the optimized parameters. Superior machining performance, higher surface quality, and increased operational dependability were attained with the Ti6Al4V-optimized EDM process, providing industry practitioners with insightful information and useful recommendations. [ABSTRACT FROM AUTHOR]

The surface quality of milled blade-root grooves in industrial turbine blades significantly influences their mechanical properties. The surface texture reveals the interaction between the tool and the workpiece during the machining process, which plays a key role in determining the surface quality. In addition, there is a significant correlation between acoustic vibration signals and surface texture features. However, current research on surface quality is still relatively limited, and most considers only a single signal. In this paper, 160 sets of industrial field data were collected by multiple sensors to study the surface quality of a blade-root groove. A surface texture feature prediction method based on acoustic vibration signal fusion is proposed to evaluate the surface quality. Fast Fourier transform (FFT) is used to process the signal, and the clean and smooth features are extracted by combining wavelet denoising and multivariate smoothing denoising. At the same time, based on the gray-level co-occurrence matrix, the surface texture image features of different angles of the blade-root groove are extracted to describe the texture features. The fused acoustic vibration signal features are input, and the texture features are output to establish a texture feature prediction model. After predicting the texture features, the surface quality is evaluated by setting a threshold value. The threshold is selected based on all sample data, and the final judgment accuracy is 90%. [ABSTRACT FROM AUTHOR]

Bulk metallic glasses (BMGs) have excellent mechanical properties, however, it is still challenging to process high-qualtiy BMG structures for their widespread engineering applications. In this work, electrochemical machining (ECM) is adopted to process various small BMG structures with high geometrical precision and surface quality. Firstly, the electrochemical dissolution behavior of a Zr 57 Cu 20 Al 10 Ni 8 Ti 5 (at.%) BMG in NaNO 3 , H 3 PO 4 , NaCl, and HCl solutions was investigated and discussed. The results shown that obvious corrosion occurred in HCl and NaCl solutions, while mass by-products and pitting corrosion on the workpiece surface in NaCl solution affect the corrosion continuity and surface quality. Therefore, the HCl solution is selected as the electrolyte for the following ECM process. Secondly, the effects of machining parameters on the ECM performance of BMG workpieces were investigated, where the optimal machining performance was achieved with an electrolyte of 0.1 mol/L HCl, a cathode feed rate of 3 μm/s, a machining voltage of 10 V, and a duty cycle of 15%. Finally, a small round hole with a roughness (Ra) of about 0.2 μm, a sidewall taper of less than 2.83°, and a relative error of diameters of 2.1% was obtained. Another square structure (0.899 mm × 0.891 mm) with high geometrical precision and surface quality was also achieved by the optimal parameters, which validates the feasibility to machine small BMG structures using the ECM technique with its optimal parameters. [Display omitted] • The electrochemical dissolution behavior in four solutions was investigated. • HCl solution was selected as a suitable electrolyte for the ECM process. • The effects of machining parameters on ECM performance were investigated. • Optimal processing parameters for the ECM of Zr57 BMG were obtained. • Typical small BMG structures were fabricated. [ABSTRACT FROM AUTHOR]

Grinding surface quality is a key indicator to determine the performance of parts and the reliability of products. During the grinding process, the pre-control technology makes appropriate adjustments in advance on its key aspects to improve the grinding surface quality. Therefore, this paper constructs a data-driven pre-control system for grinding surface quality including target layer, acquisition layer, analysis layer, and application layer. From the perspective of this system, the research progress of grinding surface quality by data-driven is reviewed. In the target layer, the connotation, formation mechanism, and main influencing indexes of grinding surface quality are described in detail. In the acquisition layer, the acquisition and processing methods of grinding data and their advantages and disadvantages are comprehensively analyzed. In the analysis layer, the methods of using result data, process data, and real-time signal data to characterize grinding surface quality are introduced. In the application layer, the research status of grinding surface quality prediction, optimization, and control are comprehensively and systematically summarized. Finally, the paper presented a summary and outlook on the improvement of grinding surface quality by data-driven. [ABSTRACT FROM AUTHOR]

Copyright of Diamond & Abrasives Engineering is the property of Zhengzhou Research Institute for Abrasives & Grinding and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Polymeric resins are becoming increasingly popular in medical and engineering applications due to their properties, such as their low weight, high strength, corrosion resistance, non-allergenicity, and extended service life. The grinding process is used to convert these materials into desired products, offering high accuracy and surface quality. However, grinding generates significant heat, which can potentially degrade the material. This study investigates the grinding of acrylic-based resins, specifically focusing on the interplay between the grind zone temperature and surface finish. The low glass transition temperature (57 °C) of the acrylic necessitates the precise control of the grinding parameters (spindle speed, feed rate, depth of cut, and grinding wheel grain size), to maintain a low temperature and achieve high-quality machining. Thermal imaging and thermocouples were employed to measure the grind zone temperature under various grinding conditions. This study investigates the influence of four parameters: spindle speed, feed rate, depth of cut, and grinding wheel grain size. The best surface finish (Ra: 2.5 µm) was obtained by using a finer-grained (80/Ø 0.18 mm) grinding wheel, combined with slightly adjusted parameters (spindle speed: 11.57 m/s, feed rate: 0.406 mm/rev, depth of cut: 1.00 mm), albeit with a slightly higher grind zone temperature (~54 °C). This study highlighted the importance of balancing the grind zone temperature and surface finish for the optimal grinding of acrylic-based resins. Further, this research finds that by carefully controlling the grinding parameters, it is possible to achieve both a high surface quality and prevent material degradation. The research findings could be highly valuable for optimizing the grinding process for various medical and engineering applications. [ABSTRACT FROM AUTHOR]

Ductile iron is a heterogeneous material. The presence of spherical graphite and a hard and brittle structure makes the surface of the workpiece easily form pits and crack defects under harsh grinding conditions, which seriously affects the service life and service performance of the workpiece. The new assisted grinding process based on the electroplastic effect is expected to avoid the surface defects of ductile iron. By comparing the surface roughness and microstructure of conventional grinding and electroplastic-assisted grinding, the superiority of electroplastic-assisted grinding surface quality is confirmed. Further discussion is presented on the impact of grinding parameters on the workpiece's surface quality under the same electrical parameters. The results show that the sensitivity of surface roughness to grinding parameters from strong to weak is grinding wheel speed, feed speed and grinding depth. The optimal combination of grinding parameters is determined as a grinding wheel speed of 30 m/s, a feed speed of 0.5 m/min and a grinding depth of 10 μm. [ABSTRACT FROM AUTHOR]

The precision of scroll machining plays a crucial role in scroll compressor efficiency. However, the improvement in scroll surface quality usually comes at the cost of an increase in energy consumption, so a trade-off between surface quality and energy consumption is required. Here in, we concentrate on optimizing several scroll end milling parameters including depth of cut, feed rate, cutting speed, and radial depth of cut to enhance the efficiency of scroll compressors, which greatly influence manufacturing responses like cutting force, surface roughness, and machining time. First, a set of scroll milling experiments are conducted and analyzed by the Taguchi L25 orthogonal array. Then, a single response optimization is done by the Taguchi method to show the impact of the milling parameters on each single response. Furthermore, the Taguchi method associated with the desirability function is applied to optimize the multi-response outputs. According to the analysis of variance (ANOVA) for the single-response, feed rate is found the most significant factor, while the results of the multi-response analysis prove that depth of cut with 37.53% is the most significant factor for the entire system. Finally, a quadratic regression analysis is performed to verify the validation of optimized results. The results revealed a 44.04% improvement in machining time, accompanied by a 2.46% enhancement in composite desirability. This demonstrated a perfect fit between the measured and expected values, achieving a balance between surface quality and energy consumption. The optimization results provide a guidance for the high-surface quality machining of scrolls and could be directly applied in the manufacturing processes of scroll compressors. [ABSTRACT FROM AUTHOR]

The core‐back process has substantially increased the range of applicability of foam injection molding (FIM) by increasing the pressure drop rate and expansion ratio. However, cell nucleation and growth occur concurrently with the flow of the melt/gas mixture during the filling stage, resulting in poor surface quality and a non‐uniform cell structure. This study investigated foam injection molding with gas counter pressure (GCP) and core‐back to produce foamed components, with comparison to high‐pressure FIM with core‐back process. Through this method, the nucleation during filling is suppressed. The surface roughness was improved to 0.987 μm, a 59% reduction compared to high‐pressure injection molding foam with core‐back. In addition, the cell uniformity was improved, measured at two locations near and far from the gate, the cell density reaching 1.7 × 105 and 2.1 × 105 cells/cm3, and cell size measuring 120.88 and 129.57 μm, respectively. GCP also prevented the formation of the bubbles larger than 500 μm at the location far from the gate. Even at the lowest recommended mold temperature, the combination of GCP and core‐back enables the production of high‐quality foamed components with reduced cooling time. Highlights: Preventing the simultaneous occurrence of cell nucleation, growth and melt flow.Foamed material with high surface quality produced by FIM.Improving the cell uniformity throughout the foamed component.Feasibility of GCP technology in conjunction with core‐back process. [ABSTRACT FROM AUTHOR]

Elliptical vibration assisted cutting (EVAC) is gradually being one of the most potential machining methods for difficult to machine materials. However, the elliptical trajectory causes periodic residual traces on machined surface. A novel quasi-intermittent vibration assisted swing cutting (QVASC) device driven by two piezoelectric actuators is proposed to reduce the residual traces between adjacent paths and improve surface quality. An X-shaped flexure hinge was used to suppress the mutual interference between two driving shafts and realize kinematic decoupling. The mechanical configuration and geometric parameters of the proposed device were designed based on the analyzing of kinematics, dynamics, and flexible characteristics. The effectiveness of the proposed device was verified by finite element analysis and off-line performance test. Tests results show that the maximum coupling ratio of motion axis, maximum motion stroke, and minimum resolution of QVASC device are 1.65%, 19.943 μm, and 9.55 nm, which are satisfied with the design and machining requirements. Finally, systematic turning experiments were carried out to verify the effectiveness of the proposed device in restraining cutting residual traces. The experimental results indicate that the proposed device can effectively inhibit the generation of periodic residual traces, which validates the feasibility of the QVASC device. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) of metallic parts has drawn the attention of academics, industrial sectors, and individual requirements. AM can produce high-quality, functional components with near-net-shapes better than conventional methods. In addition, AM's unique advantages are reduced design constraints, material utilization, tooling costs, the ability to fuse dissimilar materials, and sustainable production. However, metal AM parts have inherent outcomes: anisotropy microstructure, poor surface quality, and limited dimensional accuracy. Therefore, due to intrinsic defects, AM metals require additional (subtractive) machining as post-processes to achieve the desired part performance. This article reviews the recently published micromachining (MM) as the post-processing of metallic parts fabricated by different AM processes. For that purpose, micro-milling, micro-drilling, micro-electrical discharge machining (EDM), and hybrid-micromachining performance were determined by considering surface integrity, chip formation and cutting forces depending on AM printing parameters, machining conditions, and post-process heat treatments. Additionally, future research on improving AM components' machinability was discussed. [ABSTRACT FROM AUTHOR]

This research investigates the generation and evaluation of various geometric surface textures on PLA components produced via fused filament fabrication (FFF). Textures, including grooves, pyramids, and cylinders, were created at different depth levels on the PLA surfaces. The surface quality of these textures was assessed using a 3D optical system, focusing on area parameters such as Sa and Sz. The wettability of each texture was evaluated through contact angle and sliding angle tests, revealing the ability to modulate contact angles and achieve either hydrophobic or hydrophilic surfaces depending on the texture type. Subsequently, pairs of textured PLA pieces were bonded using a cyanoacrylate adhesive following standardised protocols, and shear tests were conducted to determine the maximum shear stress at bond (τmax) of each texture. Notably, textured surfaces generally exhibited hydrophobic properties that reduce the adhesion between the adhesive and the piece, leading to reduced maximum shear stress at bond values compared to non-textured surfaces. However, groove textures notably increased τmax values. The results were analysed to establish correlations between surface quality, wettability, and shear strength. This comprehensive evaluation aims to elucidate the influence of surface texture on the mechanical performance and adhesive properties of FFF-manufactured PLA components. [ABSTRACT FROM AUTHOR]

The machining quality plays a pivotal role in determining the service life of components. In this context, the primary focus of the experimental investigation is centered on the impact of cutting conditions during edge trimming of carbon fiber reinforced plastics (CFRP) material. The ultimate objective of this experiment is to pinpoint the most effective machining parameters, specifically the cutting speed, Vc and the feed per tooth, fz, to minimize damages during the edge trimming process using actual aerostructural sample components composed of CFRP material. Furthermore, the study took into account the issue of tool wear on cutting tools. The Design of Experiment (DoE) technique, specifically the Taguchi L9 orthogonal arrays method, was used to conduct this research. It was shown that the feed per tooth, fz, and the cutting speed, Vc, had the biggest effects on the trimmed surface quality as the longitudinal surface roughness increased. It was demonstrated that the fracture of the pyramidal tooltips in router-type tools happened more frequently at higher cutting speeds, Vc. The optimal machining parameters for minimizing damages during CFRP edge trimming were the combination of the feed per tooth, fz at 0.05 mm and cutting speed, Vc at 50 m/min. The most significant element influencing the tool's wear was the cutting speed, Vc. [ABSTRACT FROM AUTHOR]

The application of powder-based laser metal deposition in the field of industrial production has been limited for the formed geometrical morphology and mechanical performance of additive manufacturing parts. Process variable monitoring and feedback control of the deposition process is an effective method to improve the dimensional accuracy of the manufactured part. In this study, distinguished from the earlier research on processing technology of objects with a small size and a simple structure, an adaptive hybrid control method was proposed for the parts that were relatively complex in structures and required a long period of multilayer deposition. First, laser power was dynamically adjusted in real time based on the adaptive fuzzy proportional integral control algorithm to maintain the stability of each deposited layer through the monitoring of the molten pool temperature. Then, the deposited height was collected in stages and a compensation control method for the adjustment of powder feeding rate was developed. Finally, the hybrid control method was verified through the manufacture of a typical thin wall U-shaped part made of Ti6Al4V. Results show that compared to the open-loop process, deposited height deviation and the wall thickness deviation of the U-shaped part are reduced by 94.36% and 98.95%, respectively, and the surface quality is effectively improved with the value of the surface roughness (root mean square height, Sq) reduced by 70.68%. In addition, a maximum overlap volume ratio of 91.77% between the deposited model and the designed geometrical model was obtained. [ABSTRACT FROM AUTHOR]

BK7 glass, with its outstanding mechanical strength and optical performance, plays a crucial role in many cutting-edge technological fields and has become an indispensable and important material. These fields have extremely high requirements for the surface quality of BK7 glass, and any small defects or losses may affect its optical performance and stability. However, as a hard and brittle material, the processing of BK7 glass is extremely challenging, requiring precise control of machining parameters to avoid material fracture or excessive defects. Therefore, how to obtain the required surface quality with lower cost machining techniques has always been the focus of researchers. This article introduces the properties, application background, machining methods, material removal mechanism, and surface and subsurface damage of optical glass BK7 material. Finally, scientific predictions and prospects are made for future development trends and directions for improvement of BK7 glass machining. [ABSTRACT FROM AUTHOR]

These days, metal matrix composites (MMCs) are being widely utilized in automotive and aerospace industries as prominent alternatives to traditional materials. Owing to their elevated strength-to-weight proportion, exceptional fracture toughness, and lightweight design, they can be used in a variety of applications. MMCs undergo extensive machining while making parts and components out of them. The machining of monolithic materials, such as metals and alloys, is a widely used and established process in different industries, such as the aerospace, bio-medical, and automotive sectors. Because of the properties of the metal matrix and the strong reinforcement, MMCs provide unique challenges. Modern machining processes have been found to be superior in overcoming challenges and achieving improved machinability of MMCs. An overview of MMC machining with modern methods is provided in this article. This article first outlines MMCs and addresses the need for and difficulties associated with their machining. Next, it reviews previous investigations on the machining of MMCs employing modern methods like electrical discharge machining, laser machining, abrasive machining, and hybrid machining. Productivity and surface integrity issues, including delamination and roughness, etc., are discussed. When presenting the review, the benefits and drawbacks of modern processes are also taken into account. [ABSTRACT FROM AUTHOR]