Martin Pollák

Proposal of the Knowledge Application Environment of Calculating Operational Parameters for Conventional Machining Technology

Calculation of the machining parameters is one of the basic routine operations carried out before initializing the work and technological operations on a machine tool. Basis for calculating these parameters is obtained from the technical documentation in the form of rules, tables, catalogues and company literature. It can be concluded that this is a routine activity which represents a significant proportion of the activities performed before actual production of the product. It is exactly the routine activities that are possible to underpin and process well with the help of computers and appropriate application equipment. This contribution describes the design and implementation of a knowledge based system of calculation of the processing and operational machining parameters with the possibility of parameter correction with regard to specific technological equipment. The result is the obtaining of an optimal machine setting for machined range of products with a consideration for the production efficiency, durability of the cutting tool and the possibility of reusing the archived operational parameters.

THE CORRELATION OF PARAMETERS MEASURED ON ROTARY MACHINE AFTER REPARATION OF DISREPAIR STATE

The article describes the application of tools of technical diagnostics of bearings in device for the production of cellulose due to previous difficult disorder of device. Diagnostics of bearings is a very challenging area of operational diagnostics. Bearing damage may be caused by various factors such as the action of excessive forces, unsuitable lubricant, contamination of the lubricant, the lubricant oxidation, degradation of additives, etc. Such factors can significantly reduce the lifetime of technical device. The measurements and expertises that took place, as described in the article, were based on the requirement of operators technical equipment to assess the trend of selected dynamic parameters, i.e. prediction of possibilities of risk of damage to the technical system in a short time. The measurement and subsequent identification of the real state of technical device has been performed in accordance with the recommendations of standard ISO 10816-3.

Research on impacts of mechanical vibrations on the production machine to its rate of change of technical state

The article observes the amount of vibration on the bearing house of a turning lathe selected in advance through the change of the revolutions per minute and the thickness of the removed material in frontal type of lathe processing. Increase in mechanical vibration values depending on the value of nominal thickness of splinter was observed during changing technological parameters of the drilling process as a consequence of rotation speed of the motor. The vibration acceleration amplitude course changes depending on the frequencies are evaluated together for 400, 800 and 1200 motor r/min. A piezoelectric sensor of the type 4507B-004 from the Brüel & Kjaer Company was used for monitoring the frequency analysis of the vibration, which was attached to the bearing house of the lathe TOS SV 18RB. The vibration signal measured during the processing and during the time period is transformed through the means of a quick Fourier transformation to the frequency spectrum in the range of 3.0–10.0 kHz. Measured values of vibration acceleration amplitude were processed and evaluated by the SignalExpress software. Graphical abstract Unwanted vibration in machine tools like lathe is one of the main problems as it affects the quality of the machined parts and tool life and creates noise during machining operation. Bearings are of paramount importance to almost all forms of rotating machinery and are the most common among machine elements. The article describes in more detail the issue of vibrations created when machining the material by lathe turning. It also includes execution, experiment evaluation in this field, and comparison of measured vibrations’ acceleration amplitude values according to the standards.

Research and analysis of stress distribution in multilayers of coated tools

Abstract The paper analyses stress distribution in mono/multi-layers of coated tools. It presents an analysis performed on mono-layer, double-layer and multi-layer coatings using numerical models to detect the developed stress distribution and the most stressed zones in these mostly 1–10 micron layers. With such thin layers, experimental detection of stress distribution would be very difficult. Moreover, coating thickness is distributed differently on flat surfaces from on shaped features in coated tools. This non-uniform coating results solely from the technology applied and such uneven deposition of the coating is critical in terms of how the tools themselves function. The paper provides an analysis of stresses in thinner or accumulated layers of coating on the rounded edge, for example in cutting. This analysis was initiated by ProTech Coating Service, Ltd., which manufactures physical vapour deposition coatings for cutting and forming tools.

Behavior of the Beam with a Lightweight Porous Structure in Its Core

Structures, porosity of which have been modified, show special properties and functions that cannot be achieved by common conventional tools. A combination of the most suitable properties can be utilized in a particular application by controlling the composition of the porous structure. The article deals with the research of the influence of the volume ratio of the material on a behavior of the beam with the lightweight porous structure. For this research, the core inside the beam shell made of 1.431 steel was filled with a simple lattice structure with regular geometry. The beam was built-in on one side and loaded on the other. Using the finite element method, a static analysis of the beam was performed in the PTC Creo Simulate software, where the volume ratio of the material was controlled by the “struts” diameter, while the thickness of the beam shell remained constant. The analysis has shown that with an increasing volume ratio of the beam material, a stress value of the beam drops more sharply than a displacement value of the beam. The modal analysis of the beam was performed at the volume ratio 44.53%. Individual modes and obtained values of the natural frequencies were compared to the full-volume beam in order to evaluate the behavior of the lightweight beam under dynamic load. The results of the analysis have shown that the values of the natural frequencies of the lightweight beam are comparable to those of the solid beam and the deformation behavior of the both beams in the first six modes is similar.

Study of the Press Fit Bearing-Shaft Joint Dimensional Parameters by Analytical and Numerical Approach

The study of press fit bearing-shaft joint dimensional parameters by means of analytical and numerical calculations in order to identify those parameters of the press fit joints which significantly influence the life of the bearings fitted by pressing is dealt in this paper. The mounting and conditions of fit joint are the significant factors affecting the operability and life of the bearings and consequently that of rotating machines and the whole technical units. The aim of the analysis and study is to determine the tangential and radial stress, the radial displacement, and the influence of the shape features and the size of the interference on the change of the radii in the press fit bearing-shaft joint, in particular, the ball bearings of 6014 2RSR C3 type. Moreover, on the basis of obtained results, the paper discusses the impact of shaft dimensional and geometrical accuracy on the bearing lifetime.

MODIFICATION OF PRODUCTION PROCESS STRUCTURE AND OPTIMIZATION OF MATERIAL FLOW FOR SELECTED TYPES OF COMPONENTS COMPUTER SIMULATION MEANS

Material flow optimizing is a process of finding an ideal level of material continuous movement at minimum cost, time consumption, energy, resources, employees or other criteria, such as length of transport distances, transport volume per time unit, size, capacity, capacity transport unit, transportation costs, use of loading space (volume), duration of transport and so on. The article describes the optimization of material flow in production of two types of components implemented in our partner company Regada, Ltd. Presov. Creating a computer model of current state of monitored process according to basic characteristics showed the unsuitability of this solution. The problem was solved through design and subsequent verification of several alternatives. First alternative was examined by use of technological equipment for the operation. Subsequently, production process was simplified and replacement operations paths were created. The following three alternatives simulate combination of these paths with original paths.

SURFACE FINISHING OF 3D PRINTED SAMPLE MANUFACTURATED BY FUSED DEPOSITION MODELING

Currently, FDM (Fused Deposition Modelling) is one of the most widely used methods in field of functional prototypes of components creation in various industries. When using RepRap type of printing in some cases occurs to reduced quality of surface area of component that is located on a support, or complications when removing the supporting material. For low surface quality of components produced by using this technology it is necessary to adjust this surface, according to specific customer requirements. The article deals with the problems of components surface post-treatment produced by FDM technology. Using standard machining methods with support and machining process simulation in Creo 3.0 software, by testing, cutting parameters and additional surface smoothing by acetone vapor bath method.

AUTOMATIZATION PROCESS OF DESIGNING THE TECHNOLOGICAL DOCUMENTATION BY TOOLS OF COMPREHENSIVE CAD-CAM-CAE SYSTÉM

The article describes an automated production of process documentation in an environment of PTC Creo 3.0. Process documentation is a simplified form of technological documentation, which is directly generated in the environment of comprehensive CAD-CAM-CAE system. Creation of process documentation is based on design of the templates that contain all the necessary information to ensure a smooth production process by production operators. Generating takes place on the inputs received from the proposal of NC machining program. The main advantage of the creation of process documentation is its fast processing, the possibility of additional editing, archiving, graphical representation of machining sequences and tools for generating at any moment during working time. The result of the creation is generated process documentation, which represents a complete supporting documentation. Generated process documentation with the created NC program provides required information for CNC machine operators to ensure the smooth process of machining parts.

Prospective systems and technologies for the treatment of wastewater containing oil substances

The article describes the research and subsequent application of the electric coagulating agents and galvanic coagulating agents. These may be used in order to raise the standard of the treatment of wastewater containing oil substances. A method of desalination of natural waters and wastewater by means of a dialyzer with a multilayer liquid membrane was designed. Our research obtained by the new way of filtration of oil substances and suspended substances has been designed for an ultra-gentle treatment of water. In comparison with already familiar methods like ultra-filtration and reverse osmosis, this new way has certain advantages. The function of materials will be examined in this article. Based on the research, we have found that the main advantages of the method using the coagulating agent are treatment efficiency, simple installation, etc. Agents can be used to increase the level of treatment of wastewater containing crude oil substances. We found and have demonstrated that, compared to usual methods used in the industry, e.g. heating (evaporation), ion exchange and other methods of demineralization (desalination) of wastewater, the presented way has several advantages like decreasing energy losses.