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Circular saw blades, a large diameter-to-thickness ratio tool, are widely used in the aerospace and transportation sectors. However, it is limited due to its thinning tendency and weak stiffness. In this study, a novel tool tensioning technique was developed using the ultrasonic surface rolling process (USRP) to improve the tool performance of circular saw blades by changing the microstructure and residual stress distribution. Archimedean spiral curve textures were successfully created on both sides of a circular saw blade using an ultrasonic rolling experimental platform. The results show that USRP induced a gradual change in the dislocation structure from a microstrip mixing pattern to a lamellar band structure, accompanied by an increase in high-angle boundaries and a decrease in dislocation cell size. These textures result in a "low–high-low" trend in the radial residual stress distribution along the radius of the circular saw blade, and this residual stress variation improves the tool dynamic performance of the circular saw blade by more than 10% based on real-time x-direction (feed direction) cutting vibrations. In addition, a rolling tensioning evolution mechanism is proposed to explain how the synergistic effect of ultrasonic vibration and rolling force generates the residual stress field. This study elucidates the evolutionary mechanism of USRP-induced tensioning of thin circular saw blades, paving the way for a high-quality, cost-effective tensioning process. [ABSTRACT FROM AUTHOR]

The present work aims to provide the readers with a bird's-eye view of the general domain of cylindrical gear manufacturing technologies, including the cutting tools used, and related topics. The main scientific sources are explored to collect data about the subject. A systematization of the scientific works is completed, to emphasize the main issues the researchers have focused on in the past years in the domain. Several specific aspects are investigated: chip-forming process, cutting tool lifetime, the materials used to produce gear hobs, temperature and lubrication, the cutting tool geometry, cutting parameters, design methods, and optimization. Some gaps in the research have been identified, which are mainly related to the gear hob's design. These gaps, the organization of knowledge, the current requirements of the industry, and the actual socio-economic priorities form the basis for identifying new scientific research directions for the future in the area of spur gears manufacturing technologies and cutting tools. The main output of this work is a frame to guide the development of scientific research in the domain of spur gear production. [ABSTRACT FROM AUTHOR]

An innovative technology is described for improving tool performance in external turning of stainless steels: the application of new coatings to VK8 hard alloy tools. Tool performance is determined from the life of the replaceable standard cutting inserts. The working life of the inserts ends when the wear at the rear face reaches the limiting permissible value (0.5 mm). Such coatings may increase the working life of VK8 alloy tools as much as threefold, without impairing the productivity or the surface quality of the workpiece. [ABSTRACT FROM AUTHOR]

Additively manufactured (AM) cutting tools enable new design concepts in tool development concerning lightweight construction, damping behavior, and internal cutting fluid supply. So far, the impact of the layer-by-layer manufacturing technique onto the tool performance during machining of aerospace materials is widely unknown. In this study, the performance characteristics of AM indexable milling tools were investigated and compared to a conventionally manufactured tool of the same geometry. The AM tools were manufactured by laser powder bed fusion (LPBF) from a newly developed bainitic steel alloy. All tools were analyzed with two main focuses. Outside the machine tool, geometrical characteristics and mechanical properties were taken into account. Inside the machine tool, during roughing of AISI4140+QT (42CrMo4+QT) and Ti-6Al-4V (ASTM Ti-Grade 5), tool wear, cutting forces, surface roughness and vibration behavior were evaluated. Three tool concepts were compared, a conventional tool, an AM tool, and a hybrid tool with a conventionally manufactured preform and an AM head. Differences in the performance behavior could be traced back mainly to geometrical inaccuracies caused during postprocessing of the tools. Thus, LPBF-manufactured basic bodies seem to meet the requirements as applications for indexable milling tools. Based on this work, future investigations using AM cutting tools can be carried out assuming a negligible influence of the manufacturing technique onto the tool performance during machining. [ABSTRACT FROM AUTHOR]

Edge preparation can remove cutting edge defects, such as burrs, chippings, and grinding marks, generated in the grinding process and improve the cutting performance and service life of tools. Various edge preparation methods have been proposed for different tool matrix materials, geometries, and application requirements. This study presents a scientific and systematic review of the development of tool edge preparation technology and provides ideas for its future development. First, typical edge characterization methods, which associate the microgeometric characteristics of the cutting edge with cutting performance, are briefly introduced. Then, edge preparation methods for cutting tools, in which materials at the cutting edge area are removed to decrease defects and obtain a suitable microgeometry of the cutting edge for machining, are discussed. New edge preparation methods are explored on the basis of existing processing technologies, and the principles, advantages, and limitations of these methods are systematically summarized and analyzed. Edge preparation methods are classified into two categories: mechanical processing methods and nontraditional processing methods. These methods are compared from the aspects of edge consistency, surface quality, efficiency, processing difficulty, machining cost, and general availability. In this manner, a more intuitive understanding of the characteristics can be gained. Finally, the future development direction of tool edge preparation technology is prospected. [ABSTRACT FROM AUTHOR]

GW63K rare-earth magnesium (Mg-RE) alloys have been widely used in various advanced industries for their excellent mechanical properties. However, the machinability of GW63K alloys under clean cutting conditions still needs to be better understood. The novelty of this paper lies in addressing the influences of varying cutting parameters on the milling responses of GW63K Mg-RE alloys as well as the underlying mechanisms. A full-factorial design of experiments was conducted under dry cutting and minimum quantity lubrication (MQL) conditions. A three-tooth milling cutter with a diameter of 12 mm was used during the investigation. The critical milling outputs involving cutting forces, machining temperatures, and surface quality attributes were carefully analyzed. The results indicate that the cutting force highly depends on the feed per tooth, and the cutting temperature is raised with the increased cutting speed and feed per tooth. The MQL is found capable of reducing the milling temperature by 10.8 °C on average compared with dry cutting. The MQL shows benefits in improving the cutting performances of tools and surface quality of Mg-RE alloys by reducing the tool-workpiece friction coefficient and enhancing the heat dissipation conditions of the chip contact surface. In addition, lower feed per tooth and higher cutting speeds under MQL conditions are suggested for the milling of Mg-RE alloys while ensuring processing efficiency.

The present work aims to provide the readers with a bird’s-eye view of the general domain of cylindrical gear manufacturing technologies, including the cutting tools used, and related topics. The main scientific sources are explored to collect data about the subject. A systematization of the scientific works is completed, to emphasize the main issues the researchers have focused on in the past years in the domain. Several specific aspects are investigated: chip-forming process, cutting tool lifetime, the materials used to produce gear hobs, temperature and lubrication, the cutting tool geometry, cutting parameters, design methods, and optimization. Some gaps in the research have been identified, which are mainly related to the gear hob’s design. These gaps, the organization of knowledge, the current requirements of the industry, and the actual socio-economic priorities form the basis for identifying new scientific research directions for the future in the area of spur gears manufacturing technologies and cutting tools. The main output of this work is a frame to guide the development of scientific research in the domain of spur gear production.

The biological structures of Odontodactylus scyllarus, Gampsocleis grafiosa and Procambarus clarkia have interesting functions. They provide valuable inspiration for creating multi-bionic surface microstructure on Al2O3/TiC cutting tool. The microstructure is expected to effectively improve performance and reliability. This work analyzed performance and reliability of Al2O3/TiC cutting tool with multi-bionic microstructure in intermittent dry turning of AISI 52100 hardened steel. It was found that the dimension and the shape of the multi-bionic surface microstructure were greatly affected by the heat source intensity of the laser pulse. The cumulative damage Dcm of tool was negatively correlated with the fractal dimension Fmca obtained for laser-caused microscopic crack. The correlation coefficient was found to be −0.8635. On the contrary, the fracture toughness KICM was positively correlated with Fmca. The correlation coefficient had a value of 0.8731. A theoretical performance metric Pm was put forward for the tool by fusing tool stress, material damage and fracture toughness. The theoretical performance metric Pm was verified by the experimental tool life. Both tool performance and tool reliability were enhanced by using the proposed surface microstructure. Moreover, the optimum tool performance and the highest tool reliability arose simultaneously when the laser angle was 75°. Tool performance and tool reliability can be separately enhanced by 57% and 63% at this laser angle.

The paper investigates PcBN cutting tools of the BL group developed at the Institute of Superhard Materials, made with the addition of ceramic components TaN, TiC, TiN. Such materials are classified as ceramic-matrix composites (CMC). The hardness of the new modifications of composites for cutting tool purposes ranged from 31,2 to 40,2 GPa. Experimental studies were carried out under the conditions of high-speed cutting of hardened steels ShKh15 and KhVG. The performance of superhard composites was studied based on the criterion of the absence of brittle destruction of the cutting edge of the tool, and the effectiveness of new composites based on the criterion of the minimum intensity of wear of the clearance face of the indexable inserts when machining with cutting modes corresponding to the conditions of finishing. High performance parameters – quality of the finish and minimum intensity of wear have been demonstrated by tools equipped with CMC, which contain a matrix formed by titanium carbide.

The influence of the thermoelectric parameters of high-speed steels on their tribological characteristics in dry contact with structural materials is studied. For high-speed steels with low thermoemf, secondary structures develop rapidly in the gap within the frictional pair. The resulting intermediate layer has a strong screening effect. That minimizes the change in surface microrelief in frictional contact. [ABSTRACT FROM AUTHOR]

As an advanced material, ceramic matrix composites have attracted attention due to their superior properties, such as low density, high strength, and high-temperature resistance. However, it is also a typical difficult-to-cut material with the reinforcement and matrix material being of high hardness and brittleness, which makes the manufacturing of this kind of material an urgent problem. Ultrasonic vibration-assisted machining technique has advantages in decreasing cutting force, reducing tool wear, and improving machinability, making it suitable for machining hard and brittle difficult-to-cut materials. This paper has investigated ultrasonic vibration-assisted milling-grinding SiC fiber reinforced ceramic matrix composite. It aims to understand the feasibility of machining this advanced material and tool performance. Experimental results found that the ultrasonic vibration-assisted machining technique with the proper tool would be a suitable method for this advanced material. The self-designed polycrystalline diamond compact tool had a better performance and tool life. Its tool life was 4.11 times, 12 times, and 50.63 times as long as commonly used 50 mesh brazed diamond tool, 200 mesh brazed diamond tool and 100 mesh electroplated diamond tool, respectively. For a smaller cutting force and tool wear, machining parameters of a more considerable spindle speed, lower feed speed, and small cutting depth would be suggested, with ultrasonic amplitude being 4 μm and frequency being 30 kHz.

This paper develops an approach to improve a CNC machine's tool performance and slow down its degradation rate automatically in the Pre-Failure stage. A Deep Reinforcement Learning (DRL) agent is developed to optimize the machining process performance online during the Pre-Failure interval of the tool's life. The Pre-Failure agent that is presented in the proposed approach tunes the feed rate according to the optimal policy that is learned in order to slow down the tool's degradation rate, while maintaining an acceptable Material Removal Rate (MRR) level. The machine learning techniques and pattern recognitions are implemented to monitor and detect the tool's potential failure level. The proposed mechanism is applied to a CNC machine when turning Titanium Metal Matrix Composites (TiMMC). A CNC machine Digital Twin (DT) is developed to emulate the physical machine in the digital environment. It is validated with the physical machine's measurements. The proposed pre-failure mechanism is a model-free approach, which can be implemented in any machining process with fewer online computational efforts. It also validated on a wide range of cutting speeds, up to 15,000 RPM. Deployment of the proposed machine learning approach for the particular case study improves the tool's Time to Failure (T2F) by 40% and the MRR by 6%, on average, compared to the classical approach. [ABSTRACT FROM AUTHOR]

Milling is a machining method used extensively nowadays in the manufacturing industry. In the milling process, one of the most important parameters affecting the machining performance is cutting tool geometry. In general, the effects of helix and rake angles, which are among the most important geometric parameters, on tool performance, are significant. In this study, the cutting force performance of wave form end mills that have a limited investigation both in the industry and academia is analyzed. The essential geometric factors in wave form end mills are designed with variable helix and rake angle along the helical cutting edges. In this work, the cutting force performance was experimentally and numerically compared with wave form tools, which are designed for reducing cutting forces and standard tools in terms of cutting forces on gray cast iron (GG25) according to ISO 8688-2 standard. The experimental results showed that an increase in the cutting force performance of wave form tools up to 11.4% compared to standard tools. Wave form tools with different geometric forms were compared with the validated finite element method (FEM) simulations based on experimental studies. As a result of FEM analysis, lower cutting forces (14.42%, 11.45%, 8.49%) obtained by 8–0.250, 6–0.450, 8–0.350 (wavelength-wave amplitude, mm) wave form tools compared to the standard tool. In addition, increment in cutting forces (− 6.37%, − 6.06%, − 5.92%) obtained by 8–0.150, 4–0.350, 8–0.650 tools. [ABSTRACT FROM AUTHOR]

For decades, attentions have been paid to metal cutting processes, especially for the critical components in aerospace, marine, medical industries, etc. Scholars investigated the influence of cutting parameters, tool geometry, lubricant, pursuing a deeper understanding of process signatures, better tool performance, and more superior surface integrity. Edge microgeometry is proved to be an essential factor that significantly influences the tool-workpiece-chip contact, plastic deformation, and heat generation, which in turn affects the cutting phenomena. This paper aims to provide an insight and scientific overview of the role of edge microgeometries in metal cutting, with special attention on material flow state, cutting mechanics, tool performance, as well as the surface integrity. The characterization of edge microgeometries includes edge types (honed, chamfered, mixed), size parameters (edge radius, form-factor K, chamfer angle, chamfer length), and edge preparation techniques (grinding, drag finishing, brushing, micro-blasting, etc.). The researches on the influence of edge microgeometries on material flow state and cutting mechanics are reviewed, mainly focusing on analytical modeling and finite element method to explain how the edge microgeometries affect cutting processes. Then, the researches on the influence of edge microgeometries on tool performance and surface integrity are well organized to present the various findings in these topics. From the current perspective, many scholars have noticed the importance of edge microgeometries in metal cutting and have done numerous researches on this topic. Summary and future suggestions are given based on their state-of-the-art contributions in the last section. [ABSTRACT FROM AUTHOR]

Constructing bionic hierarchical structure on tool surface is an effective method for enhancing tool performance in vegetable oil-based minimum quantity lubrication (VMQL) assisted turning. Taking the features of VMQL assisted turning into account, the bionic hierarchical structure is expected to possess high durability and superoleophobicity. In this way, the structure function can be efficiently maintained and the vegetable oil droplets can be fully utilized. This work explored a novel grafting–inspired bionic hierarchical structure (GBHS) on cemented carbide tool surface. The agriculture technique named grafting provided inspiration for fusing the bionic structures obtained by examining dung beetle and lotus leaf. Two kinds of GBHS, namely VDGS and VAGS, were acquired due to the changes of the diameter D c of the bionic circular recessed microstructure and the laser processing angle A l. Morphology, wetting behavior, durable superoleophobicity, mechanism and green turning performance were analyzed for GBHS. It was verified that GBHS integrated the advantages of the bionic structures of different scales and weakened the shortcomings of them. VDGS and VAGS separately exhibited highly durable low-adhesive superoleophobicity and highly durable high-adhesive superoleophobicity when they were subjected to mechanical load and high temperature. The use of VAGS prepared at the laser angle A l of 60° caused the best machining results in short-time turning. VDGS with a diameter D c of 360 µm can be employed to acquire the optimum machining results in long-time turning. The construction strategy of GBHS can be extended to other tool materials and green machining conditions for obtaining enhanced tool performance. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract—Recommendations for expanding the applicability of tool materials in the discontinuous turning of complex parts and heterogeneous subassemblies are developed on the basis of the requirements on three modules that constitute the cutting tool: the tool module, the adjustment module, and the damping module. [ABSTRACT FROM AUTHOR]

In the paper, the results of experimental investigations of ion implanted cutting tools performance are presented. The tools, made out of Si3N4 with additives typically used for turning of Ti-6Al-4V alloy, underwent implantation with ions of yttrium (Y+) and rhenium (Re+) using the metal vapor vacuum arc method. Distribution of ions on the tool surface was measured. The cutting tools were tested in turning process with measurement of cutting forces and analysis of wear. A rather unexpected result was the increased wear of the tool after Y+ implantation with 1 × 1017 ion/cm2. It was demonstrated, however, that the tool after Y+ 2 × 1017 ion/cm2 ion implantation provided the best machining performance.

For mechanical machining the quality of cutting-tool materials is one of the most significant issues that need to be addressed. Enhancement of cutting tool performance may be achieved through the use of modern composition ceramic cutting tools This may be enabled through surface treatment, and also hot pressing and spark plasma sintering – the two main processes used for manufacturing such tools. In this article the advantages and disadvantages of the technologies and processes involved are analyzed and compared to identify the most appropriate methods for creating ceramic cutting-tools. In parallel the latest improvements in ceramic cutting-tool materials are reviewed. The paper shows that the choice of ceramic cutting tools is a quite complex process with a number of important factors to be taken into account.

CFRP/Ti stacks have become a viable alternative to conventional composite laminates and metal alloys in various aerospace applications because of their enhanced mechanical properties and improved structural functions. Machining these multilayer stacks with acceptable quality still remains a great challenge for the modern manufacturing sectors due to the ineffective management of the tool wear performance resulting from the varying properties of the stacked constituents. This paper describes, on a fundamental basis, the wear characteristics of polycrystalline diamond (PCD) tipped tools during the orthogonal cutting of CFRP/Ti stacks. Two cutting sequence strategies, i.e ., cutting from CFRP to Ti and cutting from Ti to CFRP, were implemented throughout the cutting tests. The experimental results confirm the predominance of the cutting sequence strategy in affecting the CFRP/Ti chip separation and the machined surface quality. The chip adhesion is a most influential factor leading to the disparate influences of the two cutting sequence strategies on the CFRP/Ti cutting responses. The PCD tool suffers severe crater wear due to the Ti phase cutting, while it undergoes minor flank wear owing to its superior wear resistance against abrasive carbon fibers. The wear signatures on the tool-chip contact zone via the scanning electron microscope (SEM) observation reveal that the Ti phase cutting dominates the formation of the tool crater wear land. The edge chipping occurs mainly due to the sudden force variation in the CFRP/Ti interface machining and the inherent brittleness of the PCD material. The fiber orientation seems to have a great impact on the wear behavior of utilized PCD tools by altering the tool-chip contact length. [ABSTRACT FROM AUTHOR]

Machining science is aimed at defining both cutting tools and machining conditions based on economic performance and to maintain workpiece surface integrity. Currently, machinists face a wide offer of turning, milling, drilling, and threading tools. Tools present a lot of similarities and light differences between them, being the latter the concealed reasons for a better or worse performance on difficult-to-cut alloys machining. However machinists had not useful methods for detecting which key tool aspects implies the best performance. The classic and expensive 'test-trial' method results non-viable due to the market exponential increase, both in size and specialization. This paper brings up an indirect method for seeking common features in the group of those tools with the best performance on machining Inconel 718. The method is divided into five stages, namely: (a) raw testing of a basic operation with a lot of commercial solutions for the same operation; (b) filtering of results to reduce the feasible solutions to a few ones, studying the common features of successful cases; (c) testing of these feasible solutions aimed at choosing the best insert or tool (d); and finally (e) full testing concerning all workpiece surface integrity issues. The proposed method provides knowledge based on the distilling of results, identifying carbide grades, chipbreakers shapes, and other features for having the best tool performance. All surface integrity effects are checked for the best solution. This new point of view is the only way for improving the difficult-to-cut alloys machining, reaching technical conclusions with industrial interest. This paper shows the method applied on Inconel 718 turning, resulting in a carbide grade with 10% cobalt, submicron grain size (0.5–0.8 µm) and hardness around 1760 HV, coating TiAlN monolayer with 3.5 µm thickness, chipbreaker giving 19° of rake angle that becomes 13° real one after insert is clamped on toolholder. Cutting edge radius after coating was 48 µm approximately. Cutting speed was 70 m/min higher in comparison with that recommended in handbooks. [ABSTRACT FROM AUTHOR]

Mechanical drilling has been frequently used for hole making of hybrid CFRP/Ti stacks in order to ensure excellent fastening assembly. Owing to their inhomogeneous behavior and poor machinability, drilling CFRP/Ti stacks in one-shot time has brought great challenges to the modern manufacturing community. Compared to the previous studies on drilling CFRP/Ti, this paper aims to highlight the following aspects: ( i ) the features of tool-work interaction and machinability classification in the bi-material drilling, ( ii ) the influences of different cutting sequences on CFRP/Ti drilling responses, and ( iii ) the effects of different tool geometries/materials on CFRP/Ti drilling performance. The experimental results have shown that the drill geometrical features, which ensure the cutting contacts of the stack combination, have a more significant effect on CFRP/Ti drilling output than tool material composition. The Ti → CFRP drilling strategy promotes higher quality of the machined hole surfaces ( e.g. , more consistent hole diameters and much better surface finish) with lower Ti burr extents, while the CFRP → Ti drilling strategy reduces only the induced delamination. The experiments discussed in this paper allow besides several recommendations for the cutting sequence selection and drill geometrical design when drilling hybrid CFRP/Ti stacks. [ABSTRACT FROM AUTHOR]

The temperature dependence of the electromagnetic properties of hard tool alloys is studied experimentally. Temperature intervals corresponding to maximum alloy performance are identified. A method is proposed for determining the maximum-performance temperature of hard-alloy cutting inserts from the temperature dependence of the electromagnetic properties. [ABSTRACT FROM AUTHOR]

A method of increasing the performance of a ceramic cutter by changing the alloy structure is considered for the example of a single-carbide hard alloy. [ABSTRACT FROM AUTHOR]

In metagenomic analyses of microbiomes, one of the first steps is usually the taxonomic classification of reads by comparison to a database of previously taxonomically classified genomes. While different studies comparing metagenomic taxonomic classification methods have determined that different tools are 'best', there are two tools that have been used the most to-date: Kraken ( k -mer-based classification against a user-constructed database) and MetaPhlAn (classification by alignment to clade-specific marker genes), the latest versions of which are Kraken2 and MetaPhlAn 3, respectively. We found large discrepancies in both the proportion of reads that were classified as well as the number of species that were identified when we used both Kraken2 and MetaPhlAn 3 to classify reads within metagenomes from human-associated or environmental datasets. We then investigated which of these tools would give classifications closest to the real composition of metagenomic samples using a range of simulated and mock samples and examined the combined impact of tool-parameter-database choice on the taxonomic classifications given. This revealed that there may not be a one-size-fits-all 'best' choice. While Kraken2 can achieve better overall performance, with higher precision, recall and F1 scores, as well as alpha- and beta-diversity measures closer to the known composition than MetaPhlAn 3, the computational resources required for this may be prohibitive for many researchers, and the default database and parameters should not be used. We therefore conclude that the best tool-parameter-database choice for a particular application depends on the scientific question of interest, which performance metric is most important for this question and the limit of available computational resources.

Electroformed nickel and bulk metallic glasses (BMGs) can be designed to incorporate features with length scales ranging from millimeters to nanometers. This, combined with their good mechanical properties relative to other materials, makes them competitive candidates for manufacturing multi-scale molds to produce high volumes of polymeric microfluidics components and other micro/nano devices. Despite this attractiveness, BMGs are newly developed engineering materials and their capabilities as a mold material have not been evaluated. This paper compares the performance of nickel tools made by an electroforming process and BMG tools made by a thermoplastic forming process, specifically with regard to typical microfluidics patterns and features. Ni shows excellent capabilities for good feature replication. BMG thermoplastic forming is highly dependent on the choice of alloy composition, which restricts the achievable feature size and aspect ratio. Compared to Ni, BMG has hardness values that are close to those of stainless steel and shows the superior mechanical strength that is required for mass production applications. However, oxidation in BMG tool manufacturing process affects the tool surface finish significantly and reduces the tool’s corrosion resistance. Future development of BMG tools include preventing the formation of oxidation layers or developing BMGs with an anti-oxidation composition, and further reducing their overall cost and widening its processing window parameters. Despite these challenges, however, BMGs are shown to combine excellent mechanical properties and capabilities for multi-scale forming; this makes them significantly more attractive than relatively soft Ni tools. [ABSTRACT FROM AUTHOR]

Al 2 O 3 -based ceramic tool has been widely utilized in hard cutting. It is more prone to failure in interrupted hard cutting because of the fierce cutting condition. In addition, green cutting has aroused great interest due to the increasing attention to environmental issues. Taking the advantages of surface microstructure into account, it is crucial to propose ceramic tool surface microstructure suitable for green interrupted hard cutting. A novel bionic multifunctional surface microstructure was designed for efficient performance improvement of Al 2 O 3 /TiC ceramic tool in green interrupted hard cutting. Minimum quantity lubrication (MQL) and vegetable oil were employed to achieve green cutting. Manis pentadactyla and honeycomb were used for reference in the design of the novel bionic microstructure with multiple functions such as impact resistance, lubricant storage and spontaneous lubricant transport. The first two functions served as the basis of spontaneous lubricant transport. Surface modification and nanosecond laser processing were utilized in microstructure fabrication. Different combinations of nanosecond laser parameters such as laser angle θ l and scan number n s were employed in the fabrication. This study analyzed the geometry features and various behaviors for different microstructures. Then, the external cutting load, the fracture toughness and the internal micromechanical features were integrated in a theoretical performance index. This work examined the influences of the microstructures on the performance index and the experimental performance of the ceramic tool. It was found that multifunction was achieved for the bionic microstructure. The proposed bionic microstructure provided a new way for efficient improvement of tool performance. [ABSTRACT FROM AUTHOR]

The influence of an antifrictional coating obtained by the formation of diamond-like carbon films on the life of hard-alloy end mills is investigated. The capabilities of an automated diagnostic complex are analyzed. Mills with a diamond-like coating are characterized by wear resistance and low adhesion. They are more effective for machine tools with an adaptive control system on account of the slowing of processes prior to tool failure. [ABSTRACT FROM AUTHOR]

Applications of high-strength CFRP are usually focused on manufacturing the key load-bearing structural components of large commercial aircrafts in modern aerospace industry. Machining of the high-strength CFRP is very challenging and difficult due to its extremely superior mechanical and physical properties. Polycrystalline diamond (PCD) tools are commonly identified as an attractive tool solution for CFRP machining. However, investigations on the cutting performance of PCD drills in high-strength CFRP drilling are limited and not widely performed. In this paper, two types of PCD drills (PCD standard twist drill and PCD special-geometric dagger drill) were adopted and evaluated when drilling one type of high-strength CFRP (T800S/250F). The experimental results confirmed that the PCD dagger drill seemed to provide a better tool-work configuration than the PCD twist drill for high-strength T800S/250F drilling in terms of better hole quality, lower tool wear and longer tool life. SEM and EDS analyses suggested that abrasive wear and adhesive wear were the dominant wear modes governing the PCD wear progression. Serious catastrophic failures like coating peeling and edge chipping took place for the PCD drills when cutting of T800S/250F CFRP. [ABSTRACT FROM AUTHOR]

The performance of nonstandard slotting cutters with mechanical fastening of the cutting insert is studied experimentally. Proposals are made to decrease the consumption of energy (by mechanical fastening of the insert instead of soldering) and material (by repeated tool-holder use) and to ensure consistent quality of the cutting insert's heat treatment in cutter production. [ABSTRACT FROM AUTHOR]

Diversified production requires efficient utilization of abrasive tools. To this end, prediction of grinding-wheel performance is expedient. Such prediction may be based on the wear and wear rate of the abrasive tools in specific conditions. Coefficients taking account of different wear mechanisms of abrasive grains are proposed. [ABSTRACT FROM AUTHOR]

Background: Barriers to assessing depression in advanced dementia include the presence of informant and patient recall biases. Ecological momentary assessment provides an improved approach for mood assessment by collecting observations in intervals throughout the day, decreasing recall bias, and increasing ecological validity., Objective: This study aims to evaluate the feasibility, reliability, and validity of the modified 4-item Cornell Scale for Depression in Dementia for Momentary Assessment (mCSDD4-MA) tool to assess depression in patients with advanced dementia., Methods: A intensive longitudinal pilot study design was used. A total of 12 participants with advanced dementia were enrolled from an inpatient psychogeriatric unit. Participants were assessed using clinical depression assessments at admission and discharge. Research staff recorded observations four times a day for 6 weeks on phones with access to the mCSDD4-MA tool. Descriptive data related to feasibility were reported (ie, completion rates). Statistical models were used to examine the interrater reliability and construct and predictive validity of the data., Results: Overall, 1923 observations were completed, representing 55.06% (1923/3496) of all rating opportunities with 2 raters and 66.01% (1923/2913) with at least one rater. Moderate interrater reliability was demonstrated for all items, except for lack of interest. Moderate correlations were observed between observers and patient-reported outcomes, where observers reported fewer symptoms relative to participants' self-reports. Several items were associated with and able to predict depression., Conclusions: The mCSDD4-MA tool was feasible to use, and most items in the tool showed moderate reliability and validity for assessing depression in dementia. Repeated and real-time depression assessment in advanced dementia holds promise for the identification of clinical depression and depressive symptoms., (©Iulia Niculescu, Hannah Quirt, Twinkle Arora, Terry Borsook, Robin Green, Brett Ford, Andrea Iaboni. Originally published in JMIR Aging (https://aging.jmir.org), 04.08.2021.)

In the paper, the results of experimental investigations of ion implanted cutting tools performance are presented. The tools, made out of Si3N4 with additives typically used for turning of Ti-6Al-4V alloy, underwent implantation with ions of yttrium (Y+) and rhenium (Re+) using the metal vapor vacuum arc method. Distribution of ions on the tool surface was measured. The cutting tools were tested in turning process with measurement of cutting forces and analysis of wear. A rather unexpected result was the increased wear of the tool after Y+ implantation with 1 × 1017 ion/cm2. It was demonstrated, however, that the tool after Y+ 2 × 1017 ion/cm2 ion implantation provided the best machining performance. [ABSTRACT FROM AUTHOR]