Small-scale vegetable producers often do not have modern mechanical equipment; as a result, a significant amount of inter-row and all intra-row weeding is performed manually. The development of small, affordable machines increases the competitiveness of organic vegetable production, improves sustainable land use, and reduces dependence on unwanted herbicides. In this study, a simple modular lightweight e-hoe with the capability for both inter-row (1st degree of freedom) and intra-row (2nd degree of freedom) weeding was proposed. The e-hoe uses battery-powered in-wheel drives to move the platform (3rd degree of freedom) and additional drives to operate the tools. The e-hoe was evaluated in a small greenhouse using three different tools: a traditional hoe, an adjusted rounded hoe, and an adjusted spring tine narrow hoe. The experiments were conducted at four different tool rotation speeds, using specially designed 3D-printed models for crops and weeds for evaluation. The results indicate that the efficiency of the e-hoe rates up to 95% when the right tool design and rotation speed are combined. Based on the battery capacity, the machine can be operated for approximately 3.7 h, enabling the weeding of about 3050 plants.

Water hydraulics traditionally faces limitations, particularly concerning corrosion, lubrication challenges, and wear, as water lacks the natural lubricity of oil-based hydraulic fluids. However, with the precision and design flexibility provided by metal 3D printing, key components such as valves, or their parts, can be produced with complex internal geometries that both reduce component mass and improves flow. This enhancement has a direct impact on the efficiency and responsiveness of the hydraulic system, which is essential for proportional control applications. In our study we have analysed materials suitable for spools in sliding contacts of Maraging steel 3D printed direction control valve housing. Tribological tests focused on identifying material pairs that exhibit low friction and wear in a water-based environment, which is crucial for extending the service life and reliability of water-hydraulic systems. For comparison reason, material pairs were also tested in hydraulic oil ISO VG46. Tested materials were nitride stainless steel, anodised aluminium and bronze. The durability tests on three valves with selected material pairs were also performed. Based on tribological testing conducted in water, the lowest coefficient of friction was observed when a bronze pin slide over a 3D-printed steel plate. The minimal specific wear volume was achieved with a nitride steel pin. Additionally, anodisation was found to significantly enhance the wear resistance of aluminium. Durability tests of the valves indicated that the most suitable material combination involved a bronze spool. This study emphasizes the potential of water hydraulics in specific applications where sustainability and environmental considerations are critical.

1. This article focuses on the performance of various self-supporting (S-S) internal channel structures used in hydraulic manifolds optimized for additive manufacturing (AM). Modern directives and ...

In this study, we investigate the influence of pressure transducer installation and mounting plate geometry on the accuracy of flow characterisation in a 3D printed proportional directional control valve system. The valve itself, which was developed in our previous research work, has been confirmed numerically and experimentally. To allow measurements to be as accurate as possible, we designed and manufactured highly optimised mounting plate with integrated pressure transducers using SLM additive manufacturing process.

This study presents a novel approach for the design and optimisation of hydraulic manifolds with self-supporting geometries that are compatible with additive manufacturing. Conventional manifolds with a circular cross-section often require complex post-processing as the internal channels are not supported. In this work, configurations of cross-sectional shapes that do not require support structures are investigated. A parametric optimisation and an adjoint gradient algorithm strategy were implemented to refine the cross-sectional geometry of the internal channels with the aim of minimising pressure loss while ensuring manufacturability. Use of CFD simulations to analyse the flow behaviour and pressure losses for different design variants. The integration of self-supporting features not only improves flow efficiency but also realises the full potential of AM by reducing manufacturing time and post-processing requirements. This research contributes to the development of more efficient, production-ready hydraulic systems through simulation-based design methods that take cross-sectional geometry into account.

Metal additive manufacturing (AM) enables compact hydraulic manifolds with curved internal channels, reduced part count and integrated functionality. However, these benefits also create major inspection challenges, especially in thick metallic sections containing closely spaced and intersecting passages. This study examines the practical use of X-ray computed tomography (CT) for an industrial hydraulic manifold manufactured from maraging steel MS1 by laser powder bed fusion (LPBF). Selected cross-sections from the reconstructed CT volume were compared with the nominal computer-aided design (CAD) geometry and evaluated using a qualitative interpretability classification supported by comparative image contrast-to-noise ratio (CNR) analysis and approximate projected steel thicknesses. Clearly interpretable regions showed higher and more consistent CNR, whereas geometrically congested regions generally exhibited lower and more variable local contrast. However, projected material thickness alone did not determine interpretability, indicating an additional influence of geometric overlap, orientation and reconstruction artefacts. Particular attention was given to a channel wall adjacent to a locally collapsed external support structure. No spatially persistent through-wall discontinuity was identified, although smaller defects, local wall thinning and metallurgical changes could not be excluded. A pneumatic immersion test at 0.8 MPa showed no visible bubble formation or observable pressure decrease. This pressure exceeded the expected operating pressure of the affected relief or tank channel but was substantially below the 35 MPa maximum intended pressure of the pressure-side circuits and therefore did not constitute structural qualification. The study demonstrates that whole-component CT can provide useful local inspection information for complex LPBF manifolds, but its reliability depends strongly on local geometry and acquisition conditions. Quantitative image assessment and complementary functional testing may therefore be required when CT results are insufficient for complete qualification.