RESEARCH OF THE RHEOLOGICAL PARAMETERS OF FEED GRAIN IN THE PROCESS OF THE COMBINED IMPACT-CUTTING GRINDING

Taking into consideration current realities and various factors, which create difficulties for the effective functioning of Ukraine’s national economic system, the Agro-Industrial Complex of Ukraine acts as the most stable part of it, that is characterized by conservatism and is one of the main and stable cross-sectoral formations due to revenues. However, despite the strategic priority of the AIC, the high level of energy consumption by domestic producers does not enable providing an appropriate level of competitiveness of Ukraine’s AIC in domestic and foreign markets, at the same time the rationalisation of energy use necessitates the substantiation of the energy-saving variant of its development by implementing energy-efficient machines and technologies in the system of feed preparation and feeding animals. In the technological process of feed preparation, the share of energy consumption for grinding can be more than 50%. Thus, it becomes obvious that the profitability and competitiveness of the livestock industry largely depend on the energy efficiency of realizing this technological operation, and the reduction of energy intensity in this process is an urgent task. Modelling energy-saturated mechanical processes, particularly for the grinding operation, it is necessary to consider structural-mechanical properties of the product, its ability to deform in different modes of interaction with the executive body of the technological machine. The six-link mechanical-rheological model, which is built by combining the simplest models of rheological bodies and enables reproducing the structural and mechanical properties of the object of processing – maize grain with the required degree of reliability, has been offered in the article. Theoretical research of the rheological characteristics of the material, including the assessment of the relative deformation of the maize grain in the grinding process using he impact-cutting method depending on the moisture content and internal force factors, has been conducted. In the future, the obtained results will be used to evaluate the parameters of plastic and elastic absolute deformations in the material while studying the kinetics of the grinding process.

Study on Working Performance of Multi-impact Drum

The current depletion of high-quality coal seams, hard coal mining had become the norm, while the traditional mechanical cutting methods were inefficient. A multi-impact cutting technology was proposed, which was to design a hydraulic system inside the drum. A hydraulic control system was formed by the hydraulic impact pick driver set by the ranging arm and the cutting motor to realize the reciprocating impact movement of multiple picks. The impact of picks was used to make the coal synchronously pre-crack, thereby reducing the difficulty of hard seam mining. In this paper, by analyzing the working process of the multi-impact drum, the corresponding mechanical model was established and the overall research plan was determined. A simplified drum model was established using CATIA, a coal model was established in EDEM based on the physical and mechanical properties of hard coal, and a simulation experiment composed of the cutting drum and coal model was based on orthogonality. The test method explored the working performance of the multi-impact drum under the action of multiple factors in cutting different media, using different impact frequencies and different drum speeds. The results showed that the coal breaking rate was used as the evaluation index, the order of the influencing factors was: A>C>B (coal hardness> drum speed> impact frequency), and the optimal plan combination was A2B1C3 (coal wall hardness was f5, impact frequency was 4Hz, drum speed was 40r·min -1 ); taking cutting specific energy consumption as the evaluation index, the order of influencing factors was: C>A>B (drum speed>coal hardness>impact frequency), the optimal plan combination was A2B1C3 (coal wall hardness was f5, impact frequency was 4Hz, drum speed was 40r·min -1 ). The matrix analysis method was further introduced to calculate that the order of the influence of each factor on the index value of the orthogonal test was C>A>B (drum speed>coal hardness>impact frequency), when the coal hardness was f5, the impact frequency was 4Hz, and the drum speed was 40r·min -1 , the working performance of the multiimpact cutting drum was the best. Under the same working conditions (coal hardness was f5, drum speed was 40r·min -1 ), a comparative simulation experiment of the traditional drum was carried out. Compared with the simulation results, the coal falling amount of the multi-impact drum was about 24.86% higher than that of the traditional drum, and the cutting specific energy consumption of the multi-impact drum was 0.7423kW·h/m 3 , which was about 21.67% lower than that of the traditional drum. Finally, a simplified multi-impact drum industrial cutting test was carried out. The test results showed that the cutting resistance of the multi-impact drum was about 17.22% lower than when there was no impact. Considering that the simplified multi-impact cutting drum had a reduced impact pre-cracking effect on the coal, it can be considered that the results of the industrial test and the discrete element simulation test were still relatively consistent. The multi-impact cutting drum had good working performance under hard coal conditions.

Studies of a Rotary–Centrifugal Grain Grinder Using a Multifactorial Experimental Design Method

A scientific and technical literature review on machines designed to grind fodder grain revealed that the existing designs of grinding machines—those based on destruction by impact, cutting, or chipping—have various drawbacks. Some disadvantages include high metal and energy intensity, an uneven particle size distribution of the ground (crushed) product, a high percentage of dust fraction, the rapid wear of work tools (units), and heating of the product. To eliminate most of the identified shortcomings, the design of a rotary–centrifugal grain grinder is proposed in this paper. The optimization of the grinder’s working process was carried out using experimental design methodology. The following factors were studied: the grain material feed, rotor speed (rpm), opening of the separating surface, number of knives (blades) on the inner and outer rings, technical conditions of the knives (sharpened or unsharpened), and the presence of a special insert that is installed in the radial grooves of the distribution bowl. The optimization criteria were based on the amount of electricity consumed by and the performance of the rotary–centrifugal grain grinder. The quality of performance was quantified by the finished product, based on the percentage of particles larger than 3 mm in size. An analysis of the results of the multifactorial experiment allowed us to establish a relationship (interaction) between the factors and their influence on the optimization criteria, as well as to determine the most significant factors and to define further directions for the research of a centrifugal–rotary grain grinder. From our experimental results, we found that the grinder is underutilized in the selected range of factor variation. Furthermore, the number of knives installed at the second stage of the grinder, the gap (clearance) of the separating surface, and the technical condition of the knives are among the most important factors influencing the power consumption and the quality of the resulting product. A reduction in the number of knives at the first stage has a positive effect on all the selected optimization criteria; and by varying the factors in the selected range, it is possible to obtain a product corresponding to medium and coarse grinding.

Trimming of Flat and Tubular Components by High Speed Impact Cutting (HSIC)

The trend for lightweight construction, especially in the automotive industry, leads to increased use of corresponding lightweight materials. In addition to novel construction materials such as fiber-reinforced plastics, established materials such as steel or aluminum are continuously being further developed, which is usually accompanied by a distinct increase in their strength. Beside material-related lightweight construction, new designs are applied such as the profile design. The disadvantage of this development is that established forming processes such as deep drawing, profile bending, hydroforming but also shearing of high-strength components increasingly reach their process limits. Particularly, in the case of trimming of high-strength components such as press-hardened components, it is hard to present conventional shearing processes in serial processes due to low tool life and deficient cutting surface quality. For this reason the laser cutting technology is often used. It is characterized by high flexibility and can largely meet the requirements regarding component quality. In contrast to shearing, however, it requires very long process cycle times due to its process rate, which makes it significantly less productive. High speed impact cutting offers an alternative. By exploiting high speed effects in the material, which leads to adiabatic heating of the shearing zone and a related significant reduction in strength, even ultra-high strength steel materials with tensile strengths of above 1500 MPa can be cut at high quality and with a short cycle time. In order to transfer this technology to serial applications and to develop process limits, extensive investigations were carried out using high-strength sheet metal materials and tube materials. The results are presented in this paper.

Effects of Four Base Cutter Blade Designs on Sugarcane Stem Cut Quality

The cut quality of sugarcane stems during harvesting is of considerable importance, as any damage inflicted on the stems and root systems affects ratooning and reduces yield. In current conventional cutting systems for sugarcane, relatively little attention has been paid to optimizing the cutting dynamics by investigating various blade designs and configurations. One limitation of impact cutting methods is the relatively rapid blunting of the blade edges through wear, leading to stem damage. This study aimed at investigating the effects on sugarcane cut quality of four base cutter blade designs: a conventional straight blade, a 30° angled blade, a serrated blade, and a straight blade with laser cladding on its underside. Blades of each type were installed at a 45° angle on a base cutter fitted to a John Deere 3520 sugarcane harvester. Stem damage, root system damage, and stubble height were considered as cut quality indicators, and blade wear was evaluated as the percentage of metal mass loss after completing each harvesting operation. In this study, the extent of stem and root system damage was classified into nine categories: (1) undamaged stem, not uprooted, (2) undamaged stem, partially uprooted, (3) undamaged stem, uprooted, (4) partially damaged stem, not uprooted, (5) partially damaged stem, partially uprooted, (6) partially damaged stem, uprooted, (7) severely damaged stem, not uprooted, (8) severely damaged stem, partially uprooted, and (9) severely damaged stem, uprooted. The highest percentage of stems damaged during harvesting (approx. 38%) and the highest percentage of root systems damaged (approx. 36%) occurred with the angled blade. The percentages of undamaged stems for the straight, angled, serrated, and laser clad blades were 76.9%, 62.1%, 83.1%, and 72.3%, respectively; partially damaged stems were 11.25%, 21.97%, 11.29%, and 17.73%, respectively; and severely damaged stems were 11.9%, 15.9%, 5.65%, and 9.9%, respectively. Except for the angled blade, all the blades cut almost 80% of stems without affecting the root system, and only 5% of stems were uprooted. Indices for stem damage and uprooting damage were calculated to evaluate the cut quality on a scale from -1.00 (least damage) to +1.00 (greatest damage). For both indices, the serrated blade had values closest to the target value of -1.00, implying the least damage to stems and root systems. Greater stubble heights (110 mm) were observed for the angled blade, with 76% of cut stems above the target 75 mm threshold, which was selected based on the farmer’s suggestion. Comparatively less stubble height was obtained with the serrated and laser clad blades, and roughly 60% of stems were cut in the ideal range (<75 mm). Blade wear percentages per ha of harvested area, based on metal mass loss, were found to be 0.76% for the laser clad blade, 0.83% for the serrated blade, and 0.84% for the straight blade. No mass loss data were collected for the angled blade as it caused such a high level of stem damage that its test was discontinued. The results of this study classified the levels of stem and root system damage occurring in the field during harvesting and their effects on ratooning for four base cutter blade designs. Fundamental guidelines for optimal blade configurations associated with sugarcane harvesting are provided. Keywords: Blade wear, Stem damage, Stubble height, Sugarcane harvester.