Introduction. Agriculture includes one of the branches of raw material processing, the final product of which is bread making. At the same time, the most complex operation in the technological chain of bread making is the division of the finished dough into billets of the same mass. This operation is performed by vacuum-piston type dough dividers. Under operating conditions, the service life of dividers is 30-40% lower than the manufacturer’s stated. In the technical documentation there is not point of the limit state of dividers, so they continued to be used with high costs of technological materials that determine the cost of the finished product. The purpose of the work is to determine the criterion for evaluating the performance of dough dividers and the limit value of the criterion. Materials and Methods. Evaluation of the technical condition of vacuum piston type dough dividers was based on the edible oil consumption of food line WP 32 (manufacturer AIMOL). To measure the mass of the consumed oil and the mass of the dough pieces, scales were used with an accuracy of ±0.1 g and ±1 g, respectively. Results. Based on the results of the analysis of the operation principle of dough dividers, the criterion of efficiency is called the oil consumption, which is responsible for the accuracy of weighing the dough through creating a vacuum in the suction chamber when filling gaps in the coupling of parts. When evaluating the technical condition of machines by manufacturing 300 test pieces configured for a mass of 500 g the maximum oil consumption is obtained equal to 218 g. According to the maximum oil consumption, the allowed oil consumption is determined to be 109 g. Discussion and Conclusion. It is established that at bakery enterprises, about 30% of used dough dividers have an over-extreme limit state and the accuracy in weighing the dough cannot be restored by increasing the oil consumption. However, starting from the oil consumption above the allowed value of 109 g, the machines need major repairs. The obtained values of the limit and allowed state of dough dividers are widely used in bakery enterprises to assess their technical condition.

Introduction. At present, the problem of increasing performance properties of machine parts, tools and tooling by improving the physical, chemical and mechanical characteristics of their executive working surfaces is relevant. One of the modern methods of obtaining coatings on the surfaces of parts is the method of electrospark alloying. In the case of electrospark alloying, it is important to select the thermophysical properties of materials to obtain coatings with desired physicomechanical and tribological properties. The paper presents the results of the method development for calculating the unsteady temperature field of the processed material (cathode) having the form of a rectangular parallelepiped, on one side of which a doped layer is formed during electrospark alloying. Materials and Methods. To form doped layers in a drop-shaped electro-mass transfer, we used iron in the form of a parallelepiped as a being processed material (cathode) and tungsten was used as a processing material (anode). A nonlinear initial boundary value problem and a computational scheme are suggested for determining the temperature at all points (temperature field) of the cathode made in the form of a parallelepiped with the location of several heat-emitting drops on its face. Results. The paper presents an algorithm for solving the problem by the second Green’s formula of finding the temperature field in the cathode made in the form of a parallelepiped, in this case the described nonlinear model of the flow from droplets to the parallelepiped is replaced by a linear model. An algorithm is constructed and calculations are carried out to determine the temperature values at all points and the temperature flow in the cathode in the case of one average drop on its face. According to this algorithm, a software package was created and experimental calculations were carried out. The dynamics of temperature values at all points and the heat flux of the cathode points under study is shown. Discussion and Conclusion. To achieve higher coating properties and a greater efficiency of the electrospark alloying, it is necessary to calculate the temperature field and heat flow of the cathode points under studying. The proposed mathematical model is calculated for the case of one drop placed on the boundary of a heat-conducting half-space. When choosing an anode material depending on the erosion resistance to obtain the required thickness of the surface layers with the specified functional properties, the developed calculation method is used, which allows us to describe the cooling process of one drop and then use this information to average the description of the effect of heating the parallelepiped body by a number of such drops.

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.

The most complex operation in the technological process of bread production is the division of the finished dough into blanks of the same mass. Vacuum-piston type dough separators perform this operation. Under operating conditions, the service life of the machines is 30-40 percent lower than the manufacturer's stated one. (Research purpose) The research purpose is in studying the permissible values of wear on the working surfaces of parts of vacuum-piston type dough dividing machines without repair. (Materials and methods) The article considers the method of multiple regression, which consists in studying the relationship between the maximum wear of the working surfaces of parts and the consumption of edible oil to determine the permissible sizes of parts of dough-dividing machines without repair. The parts were measured in several cross-sections in width and height. The sections were selected at the points of contact of the parts when they were moved relative to each other during the working stroke. (Results and discussion) The article presents a statistical relationship between the consumption of edible oil and the significantly affecting wear of the working surfaces of the parts of the dividing device of dough dividing machines. The values of permissible wear on the working surfaces of parts were determined by the method of steep ascent. (Conclusions) Using the method of multiple regression, the received linear regression equation adequately describes the relationship of the consumption of edible oil with the wear surfaces of separating device of TD-4 vacuum-piston type dough dividing machines. Authors determined the wear on the surfaces of parts of dividing devices and their influence on the dependent variable, the consumption of edible oil. The obtained values are fundamental for fault detection and the choice of a method for restoring worn surfaces of parts.

No abstract