Sheyina A. Scientific substantiation parameters of plant raw materialcutting and improving the construction of vegetable cutting equipment

The dissertation paper brings up an issue of establishing the basic regularities of cutting the plant raw material with a segmented knife and a complex study of the impact on the process of structural and mechanical characteristics of the raw material, the geometry of the knife blade and cutting mode. The aim of the paper is to obtain mathematical dependencies and estimated values for the process description and the determination of rational parameters of vegetable raw material cutting; the development and improvement of the structures of cutting tools in vegetable cutting equipment and the improvement of the process quality. It has been experimentally establishedthat the blade speed has impact on energy consumption when cutting vegetable raw material in the velocity range used in vegetable cutting equipment in food industry. The impact of cutting speed on the elastic and frictional properties of raw materials has been established and the mathematical description of these processes has been obtained.An increase of the cutting speed leads to a decrease of the elastic properties of vegetables and a decrease of frictional force in the velocity range from 3.4×10^(-3) m/s to 2.5 m/s. Cutting speed also affects the specific cutting force of vegetable raw material, but this factor depends on the velocity range under study. At cutting speeds from 5×10^(-3) m/s to 1.25 m/s, this dependence is described by the power function. There is a decrease of specific cutting force with the speed increase. The paper has determined the vegetables cutting force at cutting speeds of 250, 400, 600 min^(− 1) and 1200, which correspond to the knives rotation modes in modern vegetable cutting equipment. The impact on the elastic properties of the geometric sizes of the raw material being cut and its orientation towards the blade during cutting is investigated and analyzed. It has been proved that the increase of raw material size leads to the increase in the modulus of elasticity by linear dependence. A multi-factor model to determine the specific force of vegetables cutting and energy consumption for different conditions of the blade and the product interaction was developed for the first time. It has been established that the elasticity modulus of the product has the greatest influence on the specific cutting force of plant materials with a linear knife. The value of the cutting speed has an impact on the nature of the elasticity modulus influence. The dissertation paper investigates the influence of cutting speed, thickness of cutting and physical properties of vegetables on the cutting quality. Thus, cutting vegetables in slices of 1-2 mm thick is recommended to perform at cutting speeds not higher than 300 min^(− 1). When cutting vegetables of 4 mm thick and more it is possible to use cutting speeds over 600 min^(-1). If these conditions are met, the quality parameters will remain optimal. Theoretical and experimental research carried out in this paper allowed to analyze the technical and the qualitative level of modern vegetable cutting equipment, to identify the main drawbacks of the constructions and the direction to search ideas for their improvement. New cutting equipment for cutting vegetables in slices, suggested in this paper, is aimed at improving the working conditions with the equipment, reducing the service time, and increasing the productivity of vegetables cutting machines. The specific feature of new constructions is the ability to smoothly adjust the cutting thickness, provided that only one cutting unit is used. This allows increasing the functionality of vegetable cutting machine and reducing its cost. The constructive execution of an exchangeable mechanism for cabbage shredding. The use of the equipment allows cutting the entire cabbage heads, avoids the need for pre-processing the raw material, improves the quality parameters of cutting, increases the productivity of the machine, improves the working conditions. The suggested developments have been tested at the food industry enterprises of Ukraine and introduced in production.