The development of restoration technology and meadows, improvement of run-down pastures, and productivity improvement of old crops of perennial grasses is an urgent problem in agriculture. The tillage traction force in seeder designing and manufacturing is an important indicator of energy efficiency. The objective of this work is to reduce traction force and ensure seeding depth uniformity by justifying the optimal chisel parameters of a grain–fertilizer–grass seeder for direct seeding in sod. The Box–Behnken method was applied to investigate the traction force dependence on the seeder velocity, seed embedding depth, chisel width, and mounting angle. The obtained optimal parameters of coulters were justified by the finite element method. Structural and technological parameters were checked using the smoothed-particle hydrodynamics method on the deformation and wear of the seeder working body. The revealed optimal coulter parameters were as follows: chisel width was 20–20.97 mm, chisel length was 145–148.9 mm, mounting angle was 75°–81.6°, and achieved minimum traction force was 720 N. These parameters ensure the quality of grass seed embedding in the sod. The theoretical data of traction force (8.27–8.39 kN) are in accordance with the experimental (8.28–8.63 kN) data under field conditions. These findings are efficient in agrotechnical and mechanical predictions regarding the occurrence of chisel residual stresses and the working lifetime of the part.

This article presents the results of an experimental study on improving the durability of cup cutters through pre-processing. A review of existing methods of increasing the durability of metal-cutting tools is carried out. The conducted experiments and simulations confirmed the application of pre-processing to increase the durability of cup cutters and the hardening of the cutting part after pre-processing, which approves the formation of a secondary contact structure in the pre-processing process. Dependence for determining a period of the durability of cup cutters at various regimes of pre-processing is deduced.

The problem of increasing the tool durability (service life) when machining hard-to-machine materials is one of the major practical problems of modern mechanical engineering. This paper aims to improve the wear resistance of modular disk mills using the pre-processing method. Second-order rotatable planning was applied for the experimental study of the pre-processing of modular disk mills. Experimental research on the pre-processing of modular disk mills was carried out on a vertical milling machine XH950A when milling a workpiece made of steel 45. It was revealed that the increase in pre-processing modes up to specific values (f = 60 mm/min; $v_c$ = 17 m/min; t = 6 min) on the tool durability period has a positive effect. At the same time, the tool durability period was increased up to T = 155 min. Tests of the machined modular disk mills were carried out in the conditions of the laboratory base to determine the durability period. After pre-processing at different modes, each modular disk mill was used to machine the workpiece until wear signs appeared on the cutting edge. At the same time, the time was recorded to determine the durability period. It was found that the optimum mode of tool preliminary pre-processing provides the best deformation and thermal conditions for hardening the tool cutting part. As a result of modeling with the ANSYS 2024 R1 program, it was found that a hardened layer is indeed formed on the cutting part of the modular disk mill after pre-processing. The results obtained show the possibility of using the preliminary pre-processing method to improve the wear resistance of other metal-cutting tools.

This article analyzes statistics on the failure of technological equipment, assemblies, and mechanisms of agricultural (and other) machines associated with the breakdown or failure of gear pumps. It was found that the leading causes of gear pump failures are the opening of gear teeth contact during pump operation, poor assembly, wear of bushings, thrust washers, and gear teeth. It has also been found that there is a problem related to the restoration, repair, and manufacture of parts in the conditions of enterprises serving the agro-industrial complex of the Republic of Kazakhstan (AIC RK). This is due to the lack of necessary technological equipment, tools, and instruments, as well as centralized repair and restoration bases equipped with the required equipment. This work proposes to solve this problem by applying AM technologies to the repair and manufacture of parts for agricultural machinery and equipment. The study results on the stress–strain state of support bushings under various pressures are presented, showing that a fully filled bushing has the lowest stresses and strains. It was also found that bushings with 50% filling and fully filled bushings have similar stress and strain values under the same pressure. The difference between them is insignificant, especially when compared to bushings with lower filling. This means that filling the bushing by more than 50% does not provide a significant additional reduction in stresses. In terms of material and printing time savings, 50% filling may also be the optimal option.

This study investigates a method for the rotational turning of external cylindrical surfaces with a particular focus on evaluating the quality of the machined surface and its stress state during the turning of 45 steel, using experimental methods and the Finite Element Method (FEM). The influence of the cutting modes on the quality indicators during rotary turning was analyzed, and their optimal values for the processing of steel 45 were determined. The results indicate that an increase in the spindle speed has a positive impact on the roughness of the machined surface, but a negative effect on hardness. Increasing the feed rate has an ambiguous impact on the quality indicators of the machined surface: it improves the roughness but reduces the hardness. With an increase in the cutting depth, both quality indicators deteriorate. In addition, using the ANSYS/LS-DYNA (Ls Pre-Post) software package, the stress-strain state of the steel 45 workpiece was calculated, and the temperature change in the cutting zone, in the chips, and on the machined surface during rotational turning was determined. This revealed that the maximum equivalent Mises stress is 1.1 MPa and the maximum temperature in the cutting zone is 287 °C. It was observed that when the cutting force fluctuates within the range of 4.8 kN-5.1 kN, the vibration occurring in the cutting zone is reduced. The results of this study indicated that rotary machining allows for increased feed, depth, and cutting speed without critical tool wear, which directly increases the productivity. It also reduces the tooling, energy, machining time, and rework costs, resulting in significant economic benefits.

This study investigates the effect of extrusion temperature and print layer thickness on the thermal conditions for interlayer bond formation during FDM printing of ABS plastic. Computer simulations were performed using SOLIDWORKS 2024^® with transient thermal analysis. Two print layer thicknesses were considered: 0.10 and 0.25 mm, and three temperatures for the newly deposited layer: 220, 240, and 260 °C. The glass transition temperature of ABS, taken as 105 °C, was used as the criterion for evaluating the thermal state of the interlayer zone. The simulation results showed that increasing the temperature of the newly applied layer increases the depth of the zone with a temperature of Tg ≥ 105 °C and the duration for which the temperature at the interlayer interface remains above the glass transition temperature. For a layer thickness of 0.10 mm, the maximum depth of this zone increased from 0.08 mm at 220 °C to 0.14 mm at 260 °C. For a layer thickness of 0.25 mm, the maximum depth increased from 0.24 to 0.37 mm. Tensile tests were conducted on ABS specimens with layer thicknesses of 0.10 and 0.25 mm to experimentally verify these findings. The experimental tests showed that increasing the thickness of the printed layer from 0.10 to 0.25 mm results in an 8.7% increase in the average maximum tensile stress of ABS plastic and an increase in the calculated relative strain. The experimental results are consistent with trends observed in thermal modeling and show that increasing printed layer thickness leads to deeper, longer-lasting heating of the previously formed material and a higher maximum load withstood by the ABS samples.