NEW METHODS OF PRODUCT CLASSIFICATION FOR COMPUTER AIDED PROCESS PLANNING SYSTEMS

Classification of engineering parts is a very demanding activity especially in process planning. It is one of the important methods utilised in the group technology approach to computer aided process planning. This paper deals with a new method of classification, which extends the possibility of engineering part classification, especially for the process planning of non-cutting processes (forging, casting, etc.

PROPOSAL OF DEVICE FOR MONITORING OF EDUCATIONAL MACHINE TOOLS

Maintaining machinery in conditions capable of production requires certain level of maintenance which should be planned in order to avoid unnecessary downtiqmes. Technical diagnostics and monitoring provides data necessary for effective targeting, planning, and optimizing maintenance actions. This article describes a proposal of a system designed for monitoring various parameters on educational machine tools of EMCO Concept series, which are widely used at schools and universities and therefore, relatively easily accessible for research without any issues regarding confidentiality, common in industrial applications. The article describes a situation for which the device was designed, measured parameters, sensors its implementation and testing

NEW METHODS OF PRODUCT CLASSIFICATION FOR COMPUTER AIDED PROCESS PLANNING SYSTEMS

Classification of engineering parts is a very demanding activity especially in process planning. It is one of the important methods utilised in the group technology approach to computer aided process planning. This paper deals with a new method of classification, which extends the possibility of engineering part classification, especially for the process planning of non-cutting processes (forging, casting, etc.

Approaches to the Computer Vision System Proposal on Purposes of Objects Recognition within the Human-Robot Shared Workspace Collaboration

The article deals with the present topic of solution of the tasks of a safe cooperation between human and robot within industrial applications. The attention is aimed at the utilization of state-in-art devices of computer vision and related methods of object recognition within the monitored zone of the laboratory of automated assembly. The article presents some steps of the computer vision system design with focus on the suitable sensors selection and experimental verification of their parameters for demands of monitoring the specified safety zones. The designed computer vision system is one of the elements of the complex safety system that is in the process of designing in the laboratory workplace conditions

Methods of pre-identification of TITO systems

The content of this article is the presentation of methods used to identify systems before actual control, namely decentralized control of systems with Two Inputs, Two Outputs (TITO) and with two interactions. First, theoretical assumptions and reasons for using these methods are given. Subsequently, two methods for systems identification are described. At the end of this article, these specific methods are presented as the pre-identification of the chosen example. The Introduction part of the paper deals with the description of decentralized control, adaptive control, decentralized control in robotics and problem formulation (fixing the identification time at the existing decentralized self-tuning controller at the beginning of control and at the beginning of any set-point change) with the goal of a new method of identification. The Materials and methods section describes the used decentralized control method, recursive identification using approximation polynomials and least-squares with directional forgetting, recursive instrumental variable, self-tuning controller and suboptimal quadratic tracking controller, so all methods described in the section are those ones that already exist. Another section, named Assumptions, newly formulates the necessary background information, such as decentralized controllability and the system model, for the new identification method formulated in Pre-identification section. This section is followed by a section showing the results obtained by simulations and in real-time on a Coupled Drives model in the laboratory. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089]; Ministry of Education, Science, research and Sport of the Slovak Republic [1247/2018]Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky; European Regional Development Fund, ERDF: CZ.1.05/2.1.00/03.008

Parameter Identification of Cutting Forces in Crankshaft Grinding Using Artificial Neural Networks

The intensifying of the manufacturing process and increasing the efficiency of production planning of precise and non-rigid parts, mainly crankshafts, are the first-priority task in modern manufacturing. The use of various methods for controlling the cutting force under cylindrical infeed grinding and studying its impact on crankpin machining quality and accuracy can improve machining efficiency. The paper deals with developing a comprehensive scientific and methodological approach for determining the experimental dependence parameters’ quantitative values for cutting-force calculation in cylindrical infeed grinding. The main stages of creating a method for conducting a virtual experiment to determine the cutting force depending on the array of defining parameters obtained from experimental studies are outlined. It will make it possible to get recommendations for the formation of a valid route for crankpin machining. The research’s scientific novelty lies in the developed scientific and methodological approach for determining the cutting force, based on the integrated application of an artificial neural network (ANN) and multi-parametric quasi-linear regression analysis. In particular, on production conditions, the proposed method allows the rapid and accurate assessment of the technological parameters’ influence on the power characteristics for the cutting process. A numerical experiment was conducted to study the cutting force and evaluate its value’s primary indicators based on the proposed method. The study’s practical value lies in studying how to improve the grinding performance of the main bearing and connecting rod journals by intensifying cutting modes and optimizing the structure of machining cycles

The Effect of Blade Angle Deviation on Mixed Inflow Turbine Performances

The choice of blades for mixed turbines is to achieve the required deflection with minimal losses. In addition, it is necessary that the blade functions without a detachment in a wide area outside the nominal operating point of the machine. In the blade profile study, it is required to satisfy the conditions relating to fluid mechanics and those relating to the possibility of realization of construction. The work carried out presents the effect of the blade deviation angle on the geometric blade shape and the performance of the mixed inflow turbine on keeping the same rotor casing in order to improve its performances. It was remarked that the efficiency is proportional to the deviation angle’s increase, but the rotor became heavy. It has been determined that the effect of the blade deviation angle on mixed inflow performances decreases dramatically starting from the angle −20° for a 100% of machine load. It was urged to avoid relying on angles greater than −20 as values for blade deviation angles. The study noted that the maximum obtained in the output work and power is related to the highest the efficiency for a specific optimum design case (−35° of deviation blade angle) due to the increase in the contact surface between the blade and the fluid, but the problem is that the rotor gets a little heavy (4.37% weight gain). Among recommendations, attention was given to the more significant absolute exit kinetic energies, for values of deviation blade angle between -10° and −20°, where an exhaust diffuser is recommended to use to recover a part of it into a greater expansion ratio. These simulation results were obtained using a CFD calculation code-named CFX.15. This code allowed for the resolution of the averaged dynamic equations governing the stationary, compressible, and viscous internal flow

Impact of Magnetic-Pulse and Chemical-Thermal Treatment on Alloyed Steels’ Surface Layer

The relevant problem is searching for up-to-date methods to improve tools and machine parts’ performance due to the hardening of surface layers. This article shows that, after the magnetic-pulse treatment of bearing steel Cr15, its surface microhardness was increased by 40–50% compared to baseline. In this case, the depth of the hardened layer was 0.08–0.1 mm. The magnetic-pulse processing of hard alloys reduces the coefficient of microhardness variation from 0.13 to 0.06. A decrease in the coefficient of variation of wear resistance from 0.48 to 0.27 indicates the increased stability of physical and mechanical properties. The nitriding of alloy steels was accelerated 10-fold that of traditional gas upon receipt of the hardened layer depth of 0.3–0.5 mm. As a result, the surface hardness was increased to 12.7 GPa. Boriding in the nano-dispersed powder was accelerated 2–3-fold compared to existing technologies while ensuring surface hardness up to 21–23 GPa with a boride layer thickness of up to 0.073 mm. Experimental data showed that the cutting tool equipped with inserts from WC92Co8 and WC79TiC15 has a resistance relative to the untreated WC92Co8 higher by 183% and WC85TiC6Co9—than 200%. Depending on alloy steel, nitriding allowed us to raise wear resistance by 120–177%, boriding—by 180–340%, and magneto-pulse treatment—by more than 183–200%

Effect of Superimposed Vibrations on Droplet Oscillation Modes in Prilling Process

This article was aimed to solve an urgent problem of ensuring quality for prilling processes in vibrational prilling equipment. During the research, the need for the application of vibrational prilling to create a controlled impact on the process of jet decay on droplets with the proper characteristics was substantiated. Based on the experimental and theoretical studies of the process of decay of a liquid jet into drops, axisymmetric droplet oscillation modes for the different frequencies were observed. Frequency ranges of transition between modes of decay of a jet into drops were obtained. As a result, the mathematical model of the droplet deformation was refined. The experimental research data substantiated this model, and its implementation allowed determining the analytical dependencies for the components of the droplet deformation velocity. The proposed model explains the existence of different droplet oscillation modes depending on the frequency characteristics of the superimposed vibrational impact. Based on an analytical study of the droplet deformation velocity components, the limit values of the characteristics defining the transition between the different droplet oscillation modes were discovered. Analytical dependencies were also obtained to determine the diameter of the satellites and their total number

EVALUATION OF MACHINE TOOL QUALITY

Paper deals with aspects of quality and accuracy of machine tools. As the accuracy of machine tools has key factor for product quality, it is important to know the methods for evaluation of quality and accuracy of machine tools. Several aspects of diagnostics of machine tools are described, such as aspects of reliability