Engineering working operations based on parameters of product manufacturability using a computer-aided design algorithm

The study aimed to develop an algorithm for computer-aided design (CAD) of working operations. A processing route for machining components was developed based on the criteria of production manufacturability, industrial data and a digital model of the product. The process of machining a workpiece was analysed using a method of theoretical separation. The machining process of a frame workpiece was used as a model. The identified formal parameters formed a basis for developing a CAD algorithm and a model of manufacturing route associated with the mechanical processing of a work-piece applying a condition-action rule, as well as mathematical logic. The research afforded a scheme for selecting process operations, given the manufacturability parameters of a product design. The concept of CAD algorithm was developed to design a production process of engineering products with given manufacturability parameters, including industrial data. The principle of forming a route and selecting a machining process was proposed. Several criteria of production manufacturability (labour intensity, consumption of materials, production costs) were selected to evaluate mechanical processing. A CAD algorithm for designing technological operations considering the parameters of manufacturability was developed. The algorithm was tested by manufacturing a frame workpiece. The developed algorithm can be used for reducing labour costs and development time, at the same time as improving the quality of production processes. The formalisation of process design is a crucial stage in digitalisation and automation of all production processes.

Impact of food processing on postprandial glycaemic and appetite responses in normoglycaemic adults: a randomized, controlled trial

Chickpeas are among the lowest glycaemic index carbohydrate food eliciting protracted digestion and enhanced satiety responses. In vitro studies suggest that mechanical processing of chickpeas significantly increases starch digestion. However,...

Innovative Technology for Stamping a Small-Sized Sleeve Blank

The work is devoted to the development of an innovative technology of stamping from low-carbon steel for small-size liner blanks. The sequence of punching transitions includes a cold back extrusion operation, two cold drawing operations with thinning, and a cold crimping operation. Simulation with the use of the finite element method established the forces and specific forces during operations, the thermal effect during shaping, the shape and size of semi-finished products with distributions of the intensity of deformations. An elastoplastic metal model was used, which made it possible to reveal the deformation forces, tool extraction from deformed semifinished products and the effort to remove semifinished products from the dies. A hollow semi-finished product is obtained by reverse extrusion. The possibility of carrying out the first drawing operation with thinning through two sequentially located dies with the formation of a hole in the bottom part is shown. After this operation, annealing of the semi-finished product is required to restore plasticity. In the second operation, thinning stretching. The shape and dimensions of the wall of the semi-finished product after the second drawing, the distribution of the intensity of deformations in it are determined from the condition of reaching the final dimensions and mechanical properties of the sleeve blank at the last crimping operation. For this, the deformations obtained as a result of the second drawing are taken into account when modeling the crimp. For each transition of stamping, a construction of stamping equipment has been developed. The proposed technology for stamping a sleeve blank can be implemented on a universal pressing equipment, has a high productivity due to a reduction in the number of transitions and minimizes mechanical processing.

Effect of the Thermo-Mechanical Processing on the Impact Toughness of a 12% Cr Martensitic Steel with Co, Cu, W, Mo and Ta Doping

This paper presents the results of an experimental investigation of a 12% Cr steel where a significant increase in Charpy impact toughness and a slight decrease in ductile-brittle transition temperature (DBTT) from 70 °C to 65 °C were obtained through thermo-mechanical processing, including interim hot forging at 1050 °C with long-term annealing at 1000 °C, as compared with conventional heat treatment. At lower temperatures ranging from −20 °C to 25 °C, the value of impact toughness comprised ~40 J cm−2 in the present 12% Cr steel subjected to thermo-mechanical processing. The amount of δ-ferrite decreased to 3.8%, whereas the size of prior austenite grains did not change and comprised about 40–50 μm. The boundaries between δ-ferrite and martensitic laths were decorated by continuous chains of Cr- and W-rich carbides. M23C6 carbides also precipitated along the boundaries of prior austenite grains, packets, blocks and martensitic laths. Thermo-mechanical processing increased the mean size of M23C6 carbides and decreased their number particle densities along the lath boundaries. Moreover, the precipitation of a high number of non-equilibrium V-rich MX particles was induced by hot forging and long-term normalizing at 1000 °C for 24 h.

Technological equipment

General information about devices, their classification and structure is presented; theoretical bases of basing, taking into account the specifics of the choice of basing schemes when choosing technological bases; designs of the main elements of machine tools, methods of their precision and power calculations of devices; design features of devices for various technological systems of mechanical processing, including CNC; features of control and measuring devices; individual issues of mechanization, automation, unification and standardization of devices; methods of designing special devices. Special attention is paid to the educational and methodological support of practical training of specialists. Meets the requirements of the federal state educational standards of secondary vocational education of the latest generation. It is intended for students of secondary vocational education institutions studying in the specialty 15.02.08 "Technology of mechanical engineering".

Special Issue “Advanced Techniques and Efficiency Assessment of Mechanical Processing”—Editorial Note and Critical Review of the Problems

The value chain of metal production consists of a number of processing steps that result in obtaining the final metal product from the given raw material [...]

Selection of rational electrochemical methods for controlling the efficiency of machining of corrosion-resistant steel

The article discusses methods of controlling the processes of mechanical processing based on electrochemical effects. The corresponding anodic polarization curves of 1X18H9T steel obtained in electrolyte solutions without and with stirring are presented. The article discusses methods of machining processes control based on electrochemical effects. Lubricating and cooling technological media (LCTM) used in machining are in most cases electrolytes, therefore, electrochemical processes and phenomena actively occur during contact dynamic machining. It is possible to control the processes of machining by acting on the system elements of the tool - LCTM- part, in particular by activating the LCTM and reducing the strength characteristics of the processed steel in the cutting zone. A reserve for increasing the efficiency of mechanical processing can be the composition selection of the applied LCTM, combined with the simultaneous electrochemical polarization of the treated surface of friction pair parts. It was found that when cutting, the efficiency of machining and the chip shapes are changed, which is explained by the influence of the current density on the strength of the processed steel. In the conditions of machining, complex dynamic processes occur due to the rotation of the work piece and/or tool, so it is necessary to take into account the hydrodynamic phenomena and processes that arise in this case. Electrode potentials are considered to be the most important characteristic of the metal cutting process. The potential of the system can regulate such processes and indicators as wear and surface micro hardness. Anodic polarization curves of the steel 1X18H9T obtained in various electrolyte solutions without stirring and with stirring on a rotating disk electrode are given. The study allowed determining the factors affecting the processes occurring in the cutting zone and to identify rational current densities due to simulating the conditions of real technological processes of the combined steel processing. The increase in the processing intensity of the steel 1X18H9T with the cutting zone polarization is associated with the action of factors activating the selective anodic dissolution of the processed alloy.