Use of Digital Twins for Mathematical Modeling of Ultrasonic Cutting of Titanium Blanks

The paper presents the results of numerical experimental studies of cutting titanium blanks using mathematical modeling programs, which make it possible to completely repeat technological processes in a computer (digital twin). The LS-DYNA product was used as a program to simulate the process of stock removal from titanium blank. It has been established that the use of this method adequately describes the cutting processes, including with the introduction of the energy of an ultrasonic field into the processing zone, can significantly reduce the duration of experimental research and evaluate the influence of the elements of the cutting mode and design parameters of the tool on the thermal power aspects of the formation of new surfaces of machine parts.

Simulation of the stock removal in the contact zone during internal grinding of brittle non-metallic materials

Introduction. Finishing operations, in particular, cylindrical grinding, essentially form the quality parameters of products, its performance characteristics and functional suitability. At the same time, the cost of grinding work increases significantly in comparison with grinding metals, reaching an average of 20 ... 28% of the total cost of manufacturing products. The selection of the optimal parameters of the technological system based on the process simulation can improve the reliability, productivity and economic efficiency. To describe the processing of brittle nonmetallic materials, empirical dependences are mainly used, and the existing analytical models do not take into account the stochastic nature of the grinding operation and the combination of microcutting and brittle chipping when removing particles of brittle nonmetallic material and wear of the surface of the grinding tool. Purpose of the work: simulation of stock removal in the contact zone during internal grinding of brittle non-metallic materials. The task is to study the features and patterns of change in the probability of material removal when the treated surface comes into contact with an abrasive tool. In the work, the theoretical and probabilistic models are obtained, allowing to reveal the patterns of material removal in the contact zone. The models make it possible to trace the regularities of the interaction of cutting and piercing grains on the surface of the workpiece and the process of removing the allowance in the contact zone due to a combination of the phenomena of microcutting and brittle chipping, considered as a random event. The research methods are mathematical and physical simulation using the basic provisions of the theory of probability, the laws of distribution of random variables, as well as the theory of cutting and the theory of a deformable solid. Results and discussion. Data are obtained that provide a clear illustration of the patterns of material removal along the contact zone at various levels. Analysis of the results obtained shows that the peripheral speed of the tool and the rotation speed of the workpiece, which are directly included in the equation for calculating the probability of material removal, significantly affect the rate of material removal. The cross feed also has a significant effect on stock removal. A qualitative picture of the change in the probability of material removal in the contact zone during grinding of holes in brittle nonmetallic materials is obtained. The obtained patterns of change in the probability of material removal when the machined surface is in contact with an abrasive tool and analytical dependences are valid for a wide range of grinding modes, tool characteristics and other technological factors.

Calculation and justification of modes of electroabrasive finishing of polyhedral channels

The process of processing various shapes with simultaneous removal of allowances from several mating surfaces using a new patented method is considered. An original tool has been created for the electro-abrasive process of stock removal at the finishing stage. The influence of the anodic component of the combined process, the possibility of its improvement by reducing the electrode wear is shown. The dynamics of electrode wear and technological modes for a new tool with its longitudinal feed with constant pressure, calculated by the proposed method, are considered. The choice of the voltage to the electrodes is substantiated, the value of which does not contradict the results of studies of other domestic scientists. Examples of the use of a new one for finishing treatment of channels with a conjugate profile of cross-sections used in cooling systems of heat engines are given.

FEATURES OF HIGH-SPEED THE SUPER-FINISHING DISCS CERAMIC

The possibility of providing high performance of super-finishing of ceramics based on the analysis of the processes of super-finishing of metal products is proved. For conducting experimental studies, a special installation has been developed, including a sharpening machine and a device for superfinishing. For such processing conditions, the necessity of using a low-rigidity technological system is justified. Discs made of ceramic materials of various machinability with diamond bars were super-finished at a cutting speed of up to 9.1 m/s and a clamping force of up to 90 N. Experimental data on the change in the value of cut allowance on the duration of treatment, the impact speed super-finishing of ceramic disks and grit sizes of diamond bars on the magnitude and rate of stock removal, roughness and waviness of machined surfaces and consumption of the tool. The results of super finishing of ceramic materials with processing of metal products are compared.

Cost-Efficient High-Throughput Polishing of Silicon Carbide Seed Crystals

Polishing of Silicon Carbide (SiC) seed crystals and substrates to achieve an extremely smooth, level surface, and an optically clear finish takes many surface finishing steps with very long processing times producing a significant amount of slurry waste and utilizing numerous lapping and polishing machines. This paper presents a newly developed cost-efficient SiC polishing process which reduces these operations to two surface finishing steps for achieving an optically clear finish on monocrystalline SiC material where the same size of diamond abrasives for lapping and polishing steps allows to carry out stock removal lapping and polishing processes on a single platform (machine) without concern of cross-contamination and making it as a very cost-efficient and high-throughput polishing process for SiC seed crystals and substrates.

DURA-BAR G2P

Dura-Bar G2P is a pearlitic gray cast iron that is used for continuous cast products. It was developed to best suit flame and induction hardening. G2P is made with a substantial amount of pearlite in the rim. This requires the least amount of stock removal for achieving a heat-treatable surface. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on machining. Filing Code: CI-68. Producer or source: Charter Dura-Bar, Inc.

Impact of physical properties of workpiece material on material removal rate at EDM

The volume stock removal from the workpiece during the EDM is one of the important parameters that characterize the productivity of the electro-erosion process itself. Therefore, in terms of the economic efficiency of the electro-erosion process, it is appropriate that the value of the MRR parameter is as high as possible. The paper describes the results of experimental research to identify the extent of influence of the physical properties of the workpiece material on the workpiece material removal rate at EDM. The experiments were carried out using an Aggregron Hyperspark 3 electro-erosion machine on selected tool steels. As a tool electrode material for experimental purposes, graphite with the designation EX-60 was chosen because of its practical advantages.