Selection of electric spark processing modes for electrodes from sintered bronze

The method of electrospark machining has proven itself well in the technology of repair and restoration of parts. The operational properties of coatings obtained by this method depend on the microstructure, chemical and phase composition of the electrode materials. A significant improvement in operational properties, for example, wear resistance, is achieved by the formation of nanostructured coatings using electrodes with a certain content of alloying nanomaterials. It is possible to obtain such materials at the lowest cost by electro-erosion dispersion of machine-building waste. This article discusses the electrodes obtained by sintering bronze powder obtained by the method of electroerosive dispersion. Such materials are new for the process of electrospark machining; therefore, it is important to study and select the optimal application modes, since a qualitative characteristic of the process is the indicator of the transfer of the electrode material to the part, which depends on the processing modes and installation parameters. The aim of the study is to select the modes of the installation for electrospark treatment for optimal deposition of the material, as well as to study the degree of coating increment during electrospark treatment. Coating was carried out using an installation for electrospark treatment mod. «Westron» type AI-007, electrode material was obtained by the technology of spark plasma sintering of bronze powder, surfacing was carried out on steel samples 14 × 14 × 40 mm in size, the work also used an Acculab ALC-210d4 analytical balance and an MG micrometer Н25 GOST 6507-90. All coatings were applied to samples with an equal area in three layers under different processing conditions. After that, the increment in the thickness and mass of the electrode material on the sample surface was measured. Based on the results of the work, formulas were obtained and graphs were built. The most optimal mode of coating with an electrode made of sintered bronze obtained from machine-building waste by the method of electroerosive dispersion was determined, which proves the consistency of this method of obtaining electrode materials.

Micrometric research results of vacuum dough divider components

Introduction. Nowadays, vacuum-type dough dividers are used in industries with a production volume of up to 4,000 loaves per day. In the dough divider operation, due to wear of the working surfaces of the piston, chamber, and drum, the gap between them goes beyond the value equal to 50 microns, which provides vacuum in the suction chamber. As a result, the suction process becomes unstable; the dough divider disturbs the weight accuracy of bakery goods. Repair of such equipment is carried out mainly through a full or partial replacement of worn parts and assemblies with new ones. To increase their durability, there is a need to develop a new highly efficient technology with the restoration of worn part surfaces using the welding and surfacing methods.Materials and Methods. A new technique of determining the number of objects for research using the “STATISTICA” program is presented. Wear surfaces of the vacuum dough divider parts are determined.Research Results. Micrometric studies of the dough divider components were carried out. They showed the presence of appreciable size distortions due to the local wear of the working surfaces. In this case, a side gap between the suction chamber and the main piston and between the drum and the suction chamber is 6 times higher than the permissible one, and a vertical gap between the division box and the piston exceeds the permissible gap by more than 10 times. Wear of the working surfaces of the dough divider parts is local in nature, while the range of values is as follows: for the main piston, it is 10-200 microns; for the gaging piston, it is 250- 900 microns; for the suction chamber and division box, it is 300-400 microns; for the drum surfaces, it is 280-300 microns.Discussion and Conclusions. The conducted micrometric studies showed the presence of appreciable size distortions due to the local wear of the working surfaces. Based on the results obtained, it can be argued that the most productive and economically viable technique for the restoration of worn surfaces of dough divider parts is, for example, the electrospark machining.

Influence of structural graphite surface electrospark machining conditions on erosion resistance

The study deals with the erosion resistance of graphite samples with an electrospark coating surfaced in different conditions. The purpose of the study was to identify the coating of better quality. During the experiment, three metals were used as the anode: tungsten, titanium, and vanadium. For erosivity, plasmatron was used