October 2022
This article deals with the injection moulding into the plastic mould. This is an unconventional approach to injection moulding, especially because the 3D printing is used to produce the mould. The mould with the same shape was made of a conventional material (aluminium) for comparison. The properties of the plastic mould were then compared to the aluminium mould. The flash was seen as the main shortcom (…)
This article deals with placement of machine tools on a foundation. Special attention is paid to the levelling adjustment process for machines with a self-supporting frame that are free-standing on a foundation. These machines are normally placed on a foundation in a statically indeterminate way. Consequently, the machine levelling adjustment process is not repeatable. This paper presents an analysis of (…)
Charging stations (CHS) for electric vehicles (EV) are considered as sources of local magnetic fields (MF). The MF created by the CHS depends mainly on the actual charging power and topology of the electrical components inside the CHS. MF are in technical practice represented by the effective value of the magnetic flux density BRMS. However, the complex view has to consider the resulting MF vector, its (…)
The article analyses the problem of measuring and examining the magnitudes of vibration amplitudes at the machining of materials by milling technology. By measuring the vibration parameter on the spindle head of a universal milling machine, the level of the vibration amplitudes magnitude during the milling process was acquired using a piezoelectric vibration sensor. The magnitudes of the vibration ampli (…)
This paper develops a model for DC motor diagnostics based on a state-space model approach. Its digital twin works in parallel with the real motor. The output signals of the motor and the digital twin from the electric current and angular velocity sensors are analyzed. The motor defects are detected by the magnitude of the discrepancy. If a defect is detected, the diagnostic system transmits information (…)
The paper deals with the comparison of the energy consumption of hydraulic systems for controlling the moves of the UDS 214 telescopic excavator. To compare energy losses in the hydraulic circuits for controlling the UDS 214 excavator moves, the flow rates of hydraulic oil were measured with a Hydrotechnik MultiSystem 5060 digital meter in these hydraulic circuits. Firstly, for the state of the UDS 214 (…)
The rated pressure of common hydraulic pumps varies depending on their principle and geometric displacement but generally doesn’t significantly exceed 400bar threshold. While this is perfectly adequate for most industrial and off-highway applications, there are applications requiring very high force that cannot be achieved by the linear actuator supplied with common pump pressure due to the space constr (…)
The energy efficiency and durability performance of axial piston machines are strongly affected by the tribological behavior of their lubricating interfaces. State-of-the-art approaches typically study these interface in isolation, neglecting possible reciprocal interactions between such interfaces. This paper presents an investigation of the mutual interaction between the piston/cylinder interface and (…)
Control of hydraulic drives using more than two pressure lines is studied as a means for improving energy efficiency, e.g. for excavators or for hydraulic power take off from sea wave power plant systems. All combinations of switching n different pressure levels to a differential cylinder provide in general 2.n force levels. In order to facilitate forces between these levels for a proper motion control, (…)
The article presents a brief overview of new electric-hydraulic systems of three selected earthmoving machines developed by means of mathematical modeling and simulation. These machines were as follows: a road tire roller, an excavator and a wheel loader. Their common feature was that a special innovative system was developed for each of them by Bosch Rexroth company (Brno) in cooperation with BUT (…)
Forging is one of the most important production methods in applications where the disadvantages of machining are not desired. However, the possibility of micro-cracking in the material at the end of the forging process should be considered. The main constraints here are the aging of hydraulic systems and possible casting defects. Therefore, in this study, the modernized process of an old forging press w (…)
Fluidic muscles have been the subject of research since the 1930s to the present day. McKibben's muscle is one of the most common ones. This type is the basis for fluidic muscles already being used commercially. The power-to-weight ratio is one of their main advantages. The disadvantage is difficult handling. The article describes experimental verification of static characteristics of fluidic muscles. D (…)
The paper is focused on the development of the digital twin of the hydraulic control valve for continuous control of the oil flow – servovalve or control valve – and their use by the testing of the control system of the test rig for the measurement and evaluation of the characteristics of the valve. The structure of the mathematical model of the control valve enables to do the parameterisation for diffe (…)
This communication deals with the graphical representation of power flows in hydromechanical drives, for use in systems- engineering activities. It points out the need for standardized symbols in mechanics to complement the well-established standards in electrics and hydraulics. Once identified and listed, the mechanical functions are arranged by classes and subclasses, which define the main families of (…)
The amount of energy losses in hydraulic systems, determined directly by the efficiency parameter, becomes one of the basic aspects related to the design of these systems. Recently, reducing the energy consumption of hydraulic drives has become one of the most important factors in, and sometimes even the main reason for, development works focused on hydrostatic drive systems in newly designed and alread (…)
Pressure intensifiers are used in specific areas of a hydraulic circuits, where increased pressure is needed, while the rest of the circuit (up to the pump) run on lower level of a working pressure. That could lead to a cheaper design of the components, while just one high pressure branch is designed on high pressure. Using pressure intensifier could also mean energy cost reductions. Rotary flow divid (…)
In this study, biochar (BC) derived from slow pyrolysis of spruce sawdust and activated BC with HNO3 were used as sorbents to remove methylene blue (MB) dye from the aqueous solution. BC was prepared by pyrolysis at temperatures of 200, 300, 400, and 500 °C. Based on the screening results, the two BCs (BC prepared at 400 °C and BC prepared at 500 °C) exhibiting a higher percentage of dye removal were se (…)
Inventory management applications using unmanned aerial vehicles (UAVs) appear to have the highest potential for use in warehouse operations. They remove the need for manual inspection, which is in most cases performed in heights using ladder, pen and paper. Moreover, it provides a competitive edge in the field of logistics while decreasing costs and improving stock management efficiency. Deployment of (…)
Sustainable development requires the research on new energy sources that will be safe and at the same time help to solve other societal problems. The paper is focusing on the analysing the heavy metals concentration of biomass and fuel mixtures of biomass and municipal solid waste. Analysis confirmed that the co-combustion of dirty fuels and biomass reduced the risk of releasing minerals and heavy metal (…)
The application of cooling systems is a relatively efficient way to ensure the required thermal comfort conditions. One option is the application of cooled ceilings, where the heat load is removed using a ceiling structure with integrated cooling panels. These systems allow for a suitable way remove the heat load, but at the same time, compared to conventional air conditioning systems, they are characte (…)
The forecast of the start date of the Etna volcano eruption is considered. For the first time in the history of volcanology, the forecast was made by two independent methods. The first method analyzed the nature of changes in electromagnetic emission in the environment surrounding the volcano, while the second method predicted the date of Etna's eruption based on a trend composed of regularly measured e (…)
The article provides theoretical and practical arguments regarding the possibility of predicting local and strong distant earthquakes around the world, based on the detection of anomalous behavior of the groundwater physical properties in the Earth's tectonically stressed zones before local and strong earthquakes. The authors suggest that many strong and major events can be predicted at least a few mont (…)
Shaping of surfaces during finish machining using intermittent abrasive tools requires optimized technological systems design and parametrization. To achieve that, theoretical base including equations of motion for discontinuous grinding and calculation of forced vibrations of elastic technological systems is implemented. Approximation of radial component of cutting force provides ability to study the d (…)
Dimensionless and criterial complexes are successfully used in many technical fields. They play an important role in research and design. There are a large number of dimensionless and criterial complexes, which have their advantages and are chosen depending on the topic and specific objectives of the study. The article considers dimensionless and criterial complexes most often used in studies of turboma (…)
Software tool for beam design was invented for educational purposes. SW Tool is based on standard formulas enhanced by Ashby’s theory. It is therefore a SW tool for structural design of profiles, considering its stability and enabling shape optimization for the most efficient use of the material. SW Tool is specialized to help the students evaluate suitable profile quickly and easily. This article deals (…)
Safety of machinery, including CNC machine tools, must be ensured in all phases of their life cycle. The operation and maintenance phase is the most important as it represents the longest period in the machine´s technical life linked to occurrence of work injuries. Every designer of a safe machine must consider also any reasonably foreseeable incorrect behaviour of the machine operator. The latest revis (…)
This paper deals with an approach to study nonlinear chatter analysis, which is based on the synthesis of linear theory for different turning conditions. Mainly, contact nonlinearities play a crucial role in the behavior of the machine tool and the stability of turning operation. However, the analysis of nonlinear systems is challenging because nonlinear system analyzes are often limited to a linearized (…)
This article is focused on the laser macro polishing of additively manufactured (AM) parts. The material that is being processed is maraging steel (MS1). The main part of the study is to find suitable parameters to significantly reduce the surface roughness of 3 surfaces with completely different topologies. The investigated parameters are scanning speed, defocussed laser and laser power. However, other (…)
This paper addresses the issue of transmission error (TE) evaluation. The motivation for writing this paper is the research on TE measurement and calculation, which focuses on finding a correlation between TE and the noise performance of spur gears. In the context of the study a research of an accurate description of the procedure for evaluating the TE waveform was carried out, but only incomplete desc (…)
Modern machining systems use horizontal and vertical data integration for the automatic monitoring and quality control of the machining operations. There are currently available some comprehensive papers focused on high-level system integration. Independently of that, there are also multiple publications focused on the automatic monitoring of specific machining operations. There is lack of presented con (…)
Robotic arms are complex mechatronic systems. Therefore, their design requires knowledge and experience from various technical fields, such as mechanics, electrical engineering, electronics or control. From the view of the requirements placed on developers, the design of robotic arms is one of the more complex tasks. Unfortunately, there is a lack of necessary specialists in this field of technology. Th (…)
Process planning for the productive machining of complex shaped parts is a comprehensive activity where the dynamic behaviour of a machine tool, workpiece and the process setting has to be taken into account. The predictive process-oriented machine tool digital twin is a digital simulation tool enabling full control of the process results with respect to the adjustment of the whole machining system and (…)
Control systems of modern machine tools are equipped with a number of functions for volumetric accuracy enhancement. These functions can compensate for all the geometric errors of the axes, which are characterized by 21 errors for a 3-axis machine tool. Compensation data are stored in compensation tables and the control system calculates actual compensation based on these tables and actual machine tool (…)
Automatic process monitoring, including tool wear monitoring, is a key aspect of improving the energy efficiency and cost of the machining process. The tool flank wear continuously increases during drilling operations. The intensity of tool wear may vary depending on the local properties of the material and the process settings. This paper shows the potential of drill condition monitoring based on machi (…)
The article deals with the design of the technology of production of polyurethane foam (PU) specimens and with their mechanical testing. A simple procedure is proposed to produce specimens with complex shapes. The procedure is tested on two different mounting foams. These specimens were subjected to several experiments. The article presents experimental results for only one mounting foam. The tests were (…)
Machinery or instruments are subjected to external forces from a base in many cases. It can have a negative influence on manufacturing accuracy, tightness, wear of machine parts, work safety etc. Therefore, it is necessary to perform suitable passive elastic bearings of machinery to eliminate external vibration from the base. An application of suitable vibroisolating materials is one way of the vibrat (…)
The paper is focused on the determination of the heat treatment effect on AW2099 welded joints properties. Laser beam welding was applied at constant welding parameters during the experiment. After the welding, solution annealing and artificial aging were applied at 150°C and 180°C for 24 hours. Subsequently, a static tensile test and microhardness measurement of welded joints were performed. The result (…)
The article deals with the design of a robot with an unconventional kinematic structure, which is able to vertically stabilize the position of the robot base for the placement of sensors and handling superstructures. The robot concept was designed to have as few actuators as possible. The robot's kinematics was solved for the purpose of simulating the robot's movement and implementation into the robot's (…)
The article deals with the concepts of a two-legged walking robot. Three kinematics concepts are proposed in order to achieve the lowest possible number of actuators and the best possible energy efficiency. Walking cycle algorithms are also proposed. These concepts have been assessed and evaluated in several respects in order to select the optimal kinematic concept.
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