The article considered the issues of the impact of technological heredity on the accuracy of obtaining dimensions during the machining of machine parts. The authors analyzed the influence of technological heredity on accuracy and quality of parts. The issues of ensuring the accuracy of processing and the dependence of the accuracy of obtaining dimensions in various locating charts are considered. Based on the theoretical analysis, the calculation was carried out, analyzing the technical processes of critical parts of various types, in which the impact of technological heredity is clearly traced; the ways to solve this problem are presented. The paper concludes that in order to obtain a product with the specified properties and requirements, it is necessary to establish the number and nature of transitions, and based on the information provided, to determine the values of intermediate and clean-up allowances, which is the initial information for calculating the total allowance.
The article analyzes the influence of errors from elastic deformations on the accuracy of processing in the conditions of complex automation. Different variants of multi-tool processing are considered: parallel processing, when different tools are alternately, one after the other, involved in the processing of the workpiece surfaces, and parallel-sequential processing, when different surfaces of the workpiece are processed simultaneously by several tools located in the working position. Design automation in machine-building production is part of the complex problem of automation of engineering work in all areas of the functioning of a modern production system. Therefore, when creating design automation systems, its connections in the general complex of automation of engineering activities in the production cycle should be taken into account. In general, the automation of the engineer's work is task planning, design and technological preparation of production, and management of the production system. The choice of favorable cutting modes for multi-tool processing is a difficult task, since, along with taking into account the features of each individual tool, it is necessary to make a general analysis of the entire setup, i.e. the set of tools used on the machine, and the distribution of processing transitions among them. Machine-building production is currently characterized by the desire to constantly update the range of released products. The requirements of multi-product manufacture can be met under the condition of its automation, which covers both the automation of production preparation and management. The article provides recommendations for reducing the error from elastic deformations in the conditions of complex automation. English version ofthe article is available at URL: https://panor.ru/articles/multi-tool-machining-in-complex-process-automation/65225.html
The article presents the review of the main methods of restoration and repair of machine parts: mechanical and bench work, welding, surfacing, metal coating, chrome plating, nickel plating, steeling (iron plating), bonding, hardening the surface of parts and restoring their shape under pressure. The areas of application of each method, its advantages and disadvantages are noted. Welding and surfacing are used to restore more than half of all repaired car parts. With the help of welding, cracks and fractures on the frame and platform are repaired, patches, various overlays and reinforcing gussets are put, and the crankcases of the units are restored. Damaged or worn threads on stub axles and other parts are restored by welding, followed by cutting a new thread. The internal threads are restored in the same way. Restoration of parts by surfacing consists in surfacing the worn working surfaces in such a way that they can be processed to the nominal or repair dimensions. When repairing cars, automatic and semi-automatic surfacing and welding under a layer of flux or in a carbon dioxide environment are used. Damaged and worn parts can be repaired by pressure. This method is based on the use of the ductility of metals. The parts are restored to their nominal dimensions with the help of special devices, by moving a part of the metal from non-working areas of the part to its worn surfaces. When restoring parts by pressure, not only their external shape changes, but also the structure and mechanical properties of the metal. Plastics are used to restore worn parts when repairing metal-cutting machines. As an adhesive, plastics are widely used for bonding broken parts, as well as for obtaining a fixed connection of parts made of metallic and non-metallic materials. When repairing metal-cutting machines, the most widely used plastics are textolite, wood laminated plastics and fast-hardening plastic — styracryl.
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