High-speed Tool Research Articles

CRUCIBLE CPM REX 54 HS

Abstract Crucible CPM Rex 54 HS is a cobalt-bearing high speed tool steel that is produced by the proprietary Crucible Particle Metallurgy (CPM) process. It combines the wear properties of the popular high vanadium M4 grade with the red hardness of the cobalt-bearing M35/Crucible CPM Rex 45 HS grades. Crucible CPM Rex 54 HS may be used as an upgrade for improved red hardness over M3 or M4 without giving up the abrasion resistance, or as an upgrade for improved wear resistance over M35 or Crucible CPM Rex 45 HS without giving up the red hardness. This datasheet provides information on composition, physical properties, microstructure, hardness, and elasticity. It also includes information on wear resistance as well as heat treating and surface treatment. Filing Code: TS-818. Producer or source: Crucible Industries LLC.

Structure and Properties of New Antifriction Composites Based on Tool Steel Grinding Waste

This article investigates the impact of manufacturing technology on the structure, mechanical, and tribological properties of new antifriction composite materials based on R6M5 high-speed tool steel grinding waste. The characteristics of the new composite’s structure formation and its impact on properties after use of the established technological modes, including grinding waste regeneration, were illustrated. It was demonstrated that such technology is capable of ensuring microheterogeneous structure. The material’s structure consists of the metal matrix based on R6M5 high-speed tool steel waste and uniformly distributed CaF2 solid lubricant in the steel matrix. As compared to known iron-based composites, this structure promotes a high degree of mechanical and tribological properties. During tribological tests, anti-seize thin films of 15–20 μm are formed on the contacting surfaces. These constantly renewable films contribute to the high antifriction properties of the composite under the studied friction conditions and provide a self-lubricating effect. Such films fully cover both the material’s surface and the counterface. The formation of antifriction films results in the self-lubrication mode. The findings of the study open up the possibility of predicting the friction behavior of a composite at high temperatures by selecting the initial metal grinding waste to ensure the appropriate level of properties. The extensive use of various alloy steel-based industrial grinding waste in the re-production cycle would significantly contribute to resolving the global environmental problem of protecting the environment from pollution.

Dynamic error of multiaxis machine tools considering position dependent structural dynamics and axis coupling inertial forces

During the working process of high-speed multiaxis machine tools, inertial forces can cause vibration and deformation of mechanical structure, which lead to the dynamic error of tool center point (TCP) relative to worktable and can adversely affect the machining performance. Considering the varying feed positions and accelerations during machining, a parameter-varying multi-rigid-body dynamic model of a 3-axis gantry machine tool is proposed. This model represents the position dependent structural dynamics and inertial forces, which can simulate the dynamic error of TCP relative to worktable within the entire workspace. The results show that the dynamic error in one direction is affected by the feed motions of multiple feed axes. The magnitudes of the dynamic error significantly vary with the position of Z-axis. And the dynamic errors in Y- and Z-direction show different varying trends. Then the theoretical model is used to discuss the dynamic error and position dependency. The expressions of TCP dynamic response and inertial forces reveal the reason why the dynamic errors in Y- and Z-direction show different varying trends.

Effect of Nd: YAG pulsed laser radiation on oxidation and segregation processes in the surface layers of T8 high speed tool steel: Tribological consequences

The paper takes a new look at studying the phase composition and structure of oxide films of the T8 tool induced by Nd: YAG laser radiation in air. It was decided that the best method for this investigation is the XPS method combined with ion depth profiling of the T8 tool steel sample by the SPECS Surface Analysis System. The maximum thickness of the oxidized FeO surface layer is 126 nm; the thicknesses of WO 3 , V 2O 5 , and V 2O 3 oxide layers of the alloying elements of T8 steel are 97 nm, 90 nm, and 126 nm, respectively. We have provided further evidence that pulsed laser radiation contributes to selective enrichment of the steel surface with W and Mo alloying elements, whose maximum is located at a depth of 90 nm. The segregation theory of Guttman ternary systems was employed to prove that the enrichment of the T8 steel surface layer is influenced by oxidative processes occurring during laser irradiation in air. In addition, we surveyed the impact of the phase composition of T8 surface oxides on their tribological properties under environmental conditions.

Uncovering process-structure relationships associated to the hot isostatic pressing of the high-speed steel PMHS 3-3-4 through novel microstructural characterization methods

Gaining insight into the many agents that determine the underlying material microstructure is essential to engineer new and efficient solutions. Tool steels resistant to abrasive wear are particularly interesting because it is possible to tailor their macroscopic properties by adjusting some of the primary carbide phase features: micromechanical properties, volume fraction, size, and shape. For many popular ledeburitic cold-work and high-speed tool steel alloys, there is a generally good understanding of the effects of the HIP temperature, pressure, and holding time on these traits. Nevertheless, there is still no thorough investigation on the influence of powder size distribution on the primary carbide phase. To that end, we employ in this work novel microstructural characterization methods that shed light on the nature and extent of its influence. We show that powder size has an enduring effect on primary carbide geometric features associated with the solidification process during powder atomization. This work contributes significant process-structure links, which uncover new opportunities for microstructural design.

Study on Development of an Operation Planning System Based on Case-Based Reasoning Using Machining Features

High-speed and high-precision machine tools developed recently have contributed to shorten machining time in parts machining. However, it consumes long time to determine operation parameters such as machining area, machining method, cutting tool and cutting conditions, and they deeply depend on operators' knowledge and experience. Thus, the preparation time before parts machining remains as a critical issue to be solved to achieve high-mix low-volume production. Therefore, in order to improve the efficiency of process planning, this study proposes an operation planning system to derive operation parameters based on case-based reasoning using recognized machining features. By using information of machining features, it becomes possible to widely deal with operation parameters such as not only cutting tool and cutting conditions, but also tool approaching and retracting patterns that are required to be input in CAM system. Additionally, since machining cases are added to a case database sequentially, the rules for case retrieval are automatically adjusted to utilize the past machining cases effectively in this system. From the result of a case study, it is confirmed that the developed system has a possibility to derive proper operation parameters in parts machining.

VIRUSBreakend: Viral Integration Recognition Using Single Breakends.

MotivationIntegration of viruses into infected host cell DNA can cause DNA damage and disrupt genes. Recent cost reductions and growth of whole genome sequencing has produced a wealth of data in which viral presence and integration detection is possible. While key research and clinically relevant insights can be uncovered, existing software has not achieved widespread adoption, limited in part due to high computational costs, the inability to detect a wide range of viruses, as well as precision and sensitivity.ResultsHere, we describe VIRUSBreakend, a high-speed tool that identifies viral DNA presence and genomic integration. It utilizes single breakends, breakpoints in which only one side can be unambiguously placed, in a novel virus-centric variant calling and assembly approach to identify viral integrations with high sensitivity and a near-zero false discovery rate. VIRUSBreakend detects viral integrations anywhere in the host genome including regions such as centromeres and telomeres unable to be called by existing tools. Applying VIRUSBreakend to a large metastatic cancer cohort, we demonstrate that it can reliably detect clinically relevant viral presence and integration including HPV, HBV, MCPyV, EBV and HHV-8.Availability and implementationVIRUSBreakend is part of the Genomic Rearrangement IDentification Software Suite (GRIDSS). It is available under a GPLv3 license from https://github.com/PapenfussLab/VIRUSBreakend.Supplementary information Supplementary data are available at Bioinformatics online.

Dynamic Simulation and Analysis of the Synchronous Mechanism of High-Speed Machine Tool Protective Cover with Joint Clearance

The synchronous mechanism is the driving part of the machine tool guide rail protection device, which makes the relative speed of each cover sheet the same, which can well reduce the vibration and noise generated by the machine tool protection device. In high-speed operation, because the gap in the hinge pair of the synchronous mechanism has a great influence on its movement accuracy, this paper establishes a multibody dynamics model of the synchronous mechanism of the high-speed machine tool guide rail guard based on the Hertz theory, and uses ADAMS to The dynamic simulation analysis of the synchronous mechanism of the clearance shows that the pin near the joint between the worktable and the cover has the greatest influence on the motion accuracy of the synchronous mechanism. At the same time, the speed of the pin is analysed under different clearances. The transformation law of acceleration, contact and collision force of the kinematic pair with clearance and its influence on the performance of high-speed machine tool guards.

CRUCIBLE REX M4

Abstract Crucible REX M4 is a special-purpose high-speed tool steel that is designed to provide high wear resistance in tools. Its high vanadium and carbon content provides superior resistance to cratering and wear in cold work punches, die inserts, and cutting applications involving high speed and light cuts. It is designed to give maximum performance while working with abrasive materials, exhibiting better wear resistance than Types M2 or M3. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-812. Producer or source: Crucible Industries LLC.

Three-dimensional computational fluid dynamic analysis of high-speed water-lubricated hydrodynamic journal bearing with groove texture considering turbulence

Water-lubricated bearings have attracted increasing attention in the field of high-speed machine tools for their low friction due to low viscosity. However, new problems, in particular, insufficient load capacity, are on the way. To the point, groove-textured journal bearing is adopted in this study. Aiming at investigating the effects of groove texture on high speed, water-lubricated, hydrodynamic journal bearing precisely, and thoroughly, three-dimensional computational fluid dynamic analyses considering cavitation and turbulence are undertaken to assess the tribological performances of the bearing. To reduce the amount of three-dimensional modeling and meshing work, mesh deformation is presented. The numerical results are compared with experiments to verify the validity of the present models and calculation procedures. Pressure distribution, load capacity, and friction of groove-textured water-lubricated journal bearing are analyzed with respect to operating conditions and geometric parameters. Comparisons between groove-textured water-lubricated journal bearing and smooth bearing are carried out to find out the influence of groove texture. It is found that the groove texture can achieve a remarkable improvement of load capacity at a smaller eccentricity ratio and higher rotary speed. The load capacity is affected by the combined effects of groove depth, width, and length. However, generally, the friction force of water-lubricated journal bearing is slightly influenced by groove texture. Results can provide theoretical guidance for the optimal design of groove-textured water-lubricated journal bearing under different operating parameters.

Inductive Heating in the Quenching of High-Speed Steel Tools

The fundamental kinetic difference between the transformation of high-speed steel on heating by high-frequency inductive current and on quenching in salt baths is considered. In heating by high-frequency current, the high temperature at the carbide–matrix boundary permits more complete carbide solution in the austenite. That improves tool quality.

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Real-time railroad track components inspection based on the improved YOLOv4 framework

According to the Federal Railroad Administration (FRA) database, track component failure is one of the major factors causing train accidents. To improve railroad safety and reduce accident occurrence, tracks need to be regularly inspected. Many computer-aided track inspection methods have been introduced over the past decades, however, inspecting missing or broken track components still heavily relies on manual inspections. To address those issues, this study proposes a real-time and cost-effective computer vision-based framework to inspect track components quickly and efficiently. The cutting-edge convolutional neural network, YOLOv4 is improved trained, and evaluated based on the images in a public track components image database. Compared with other one-stage object detection models, the customized YOLOv4-hybrid model can achieve 94.4 mean average precision (mAP) and 78.7 frames per second (FPS), which outperforms other models in terms of both accuracy and processing speed. It paves the way for developing portable and high-speed track inspection tools to reduce track inspection cost and improve track safety.

A novel printable high-speed steel filament: Towards the solution for wear-resistant customized tools by AM alternative

Additive manufacturing (AM) alternative technologies, including Fused Filament Fabrication (FFF), offer the possibility to produce both prototypes and low-volume production metallic components. This is the first time that AISI M2 high-speed steel powder is processed by FFF, achieving near full density in a complementary way to Powder Injection moulding (PIM), yet reducing the investment cost and the lead time. A completely optimized FFF process is presented: from the design of a printable highly filled metallic filament that can be fed into conventional 3D printers, to high-quality green parts that are properly debound and sintered. The final specimens (99.6% densified) are thermally treated (one quenching and two tempering) and, then, evaluated in terms of scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and mechanical characterization (hardness and wear resistance). The effect of the processing technology and the heat treatments are discussed, validating the feasibility of FFF to develop customized high-speed tools with superb performance at a competitive cost.

Evaluation of the efficiency of dry electrostatic cooling by the transfer current

Practical examples and physical mechanisms of dry electrostatic cooling efficiency when processing materials by cutting are considered. The assumption is made that efficiency of dry electrostatic cooling process depending on the mode of equipment operation directly depends on the value of electric charge carried by air flow - transfer current. A stand has been developed to measure the current flowing from an grounded plate under the action of dry electrostatic cooling airflow. Using the stand, experiments were made with the «Varkash» dry electrostatic cooling unit. As a result of the experiments, a relationship was found between the transfer current from air pressure and the length of the air flow. Experiments were made on turning structural steel with high-speed steel tools, varying the air pressure of the dry electrostatic cooling unit and the distance from the nozzle to the cutting zone. Based on the results of the experiments, it was verified that the transfer current corresponds to the efficiency of dry electrostatic cooling during cutting.

RESEARCH OF THE TECHNOLOGY OF OPENING HOLES IN COMPACT AND POWDER MATERIALS

This article is devoted to one of the important problems of mechanical engineering, including processing by cutting and deploying in sintered antifriction powder material in optimal modes with maximum performance. The study was conducted for small diameter cylindrical bushings. Processing of bushings was carried out by reamers from high-speed and carbide tools on materials from porous powder and cast iron. It is established that the temperature of the tools should not exceed the permissible upper limits, for pressing the bushings, it is necessary to use planting with small strains in the cold state. Keywords: engine valve, bushing, powder material, cast iron, reamer, cold pressing.

Experiments and Analysis for Measuring Mechanical Motion with Event Cameras

Event cameras—which detect pixelized, spatiotemporal changes asynchronously as opposed to frame-based triggered cameras—are commercially available and the topic of considerable research recently for computer vision and robotics applications. We hypothesize that these novel devices can be of utility in understanding mechanical motion by performing functions similar to high speed cameras, but with reduced bandwidth and simpler processing. To test this hypothesis, we applied multiple measurement modalities to a simple high-speed mechanical tool, including accelerometer, acoustic, and event-camera images. We also explore the utility of onboard inertial measurement units which are often integrated into these devices. Our analysis shows that these measurements are possible and consistent across modalities, possibly leading to novel new architectures for image and sensor based measurements.

Study on roughness and form errors linked with tool wear in the drilling process of an Al-Si alloy under high cutting speed using coated diamond-like carbon high-speed steel drill bits

• High cutting speed can reduce cycle time, but it can increase cutting tool wear. • High-speed steel is used in machining processes, having cutting speed limitations. • Aluminum alloys are used in mechanical parts it requires high cutting parameters. • DLC application is an alternative to reduce cutting tool wear at high cutting speed. • Process parameters are essential to ensure product quality, roughness and form errors. Materials engineering development has led to steel and cast iron replacement by Aluminum-Silicon – Al-Si alloys in various applications due to the adequate good strength-to-weight ratio and corrosion resistance. These features of Al-Si are extremely relevant for the performance improvement of many products by applying this alloy instead of the usual materials. However, studies have shown that the machinability of these materials presents multiple negative aspects, such as adhesion and abrasion. Therefore, optime cutting parameters and tools need to be selected to combine tool life with product quality. Using hard coatings with high chemical inertia, such as Diamond-Like Carbon (DLC), has shown promising results when machining aluminum alloys. Generally, in drilling, roughness, deviations in diameter, circularity and cylindricity represent the quality of a hole. Cutting speed directly influences tool wear and hole quality. Thus, this study aimed to evaluate the quality of holes machined using high-speed steel tools in an Al-Si alloy on the influence of cutting speed and the use of DLC coating. Tools with brazed Polycrystalline Diamond (PCD) are usually chosen for machining aluminum alloys, which can absorb high cutting speeds. In this paper, the replacement of brazed PCD is studied for high-speed steel coated with a thin film that can guarantee the same performance. The tests were carried out varying the cutting speed (V) in 340, 360, and 430 m/min, comparing DLC coated with uncoated tools. Flank wear was analyzed after each machining run using Scanning Electron Microscopy (SEM). The results showed that cutting speed directly influences the roughness, diameter variation, and flank wear. DLC coating did not show hole quality improvements as it presented adhesion problems on the high-speed steel substrate.

A proposal of feed rate setting for high-speed CNC milling machines by the vibration-based method

High precision and product surface finish quality are the main characteristics of these precision machine tools. Machining with different tool paths at different feed rates is applied to increase productivity. Today, machine tools using high-speed machining methods have been developed to shorten machining times and increase production capacity. However, the vibration of high-speed machine tools is the main cause of product quality reduction. The effect of the machining speed on the vibration diagnostic process of the machine is to choose the appropriate machining mode. This paper describes the vibration analysis methods of machine tools based on simulated results to determine the natural frequencies of vibration and dynamic modeling of the ball-screw feed drive system. Analysis of structural simulation results shows that the higher the rigidity of the machine, the lower the vibration amplitude, and the greater the ability to absorb and suppress vibrations for the machine tool without using dampers. Meanwhile, the combination of the measurement analysis and dynamics modeling on machine tools is an effective method for optimizing speed and controlling machining vibrations. First, the finite element model (FEM) is applied to determine the stiffness analysis and the natural vibration frequency of the machine tool. The simulation results are analyzed and compared with experimental measurement results. The vibration frequency of the ball-screw drive system during machining at different feed rates is also modeled and verified by the measurement results. Finally, the results from the proposed methods are used to predict the vibration frequency of the system, especially the ball-screw through the feed drive or rotational speed. In addition, the purpose of the proposed method is to prevent resonance by way of the forced frequency away from the natural frequency in high-speed machining. This paper proposes a survey method that can be applied for high-speed machine tools with different structures to choose an appropriate feed rate in machining.

Thermal Error Model of Linear Motor Feed System Based on Bayesian Neural Network

The linear motor feed system has been in service in complex working conditions for a long time, thus causing the nonuniform distribution of the temperature field distribution. Thus, the thermal error has become a key factor affecting system motion accuracy. In order to maximize the accuracy and efficiency of thermal error compensation for linear motor feed systems, an improved modeling method for the thermal error of the linear motor feed system based on Bayesian neural networks is proposed in combination with the strong generalization performance and avoidance of overfitting of Bayesian neural networks. And the specific modeling ideas are as follows: Firstly, the X-Y cross-type two-axis linear motor feed system is taken as the test object. Due to the traditional neural network’s slow convergence, overfitting, and underfitting problems, the Bayesian neural network is used to model the thermal error of the linear motor feed system. Secondly, to avoid the influence of multicollinearity data on the final results, the grey relation analysis method is used to screen the temperature measuring points. The data with a large relation degree is selected for modeling to ensure the prediction accuracy of the neural network. Thirdly, the temperature variables of sensitive points and thermal positioning errors are taken as data input samples. Fourthly, a Bayesian neural network model is established. Fifthly, the hyperparameters of the Bayesian neural network are determined by a calculating method of Hessian matrix by Gauss-Newton approximation. And finally, a thermal error prediction model is established. The comparison and analysis with the neural network constructed by the ordinary Levenberg-Marquardt algorithm after a series of experimental demonstrations see that the prediction accuracy of the proposed method can be enhanced by up to 10%. It also shows that the prediction model has the advantages of high precision, strong generalization ability, anti-disturbance solid ability, and strong robustness, etc. Therefore, the prediction model is expected to be widely used in predicting and compensating thermal error of the feed system of high-speed CNC machine tools in practical machining occasions.