Cutting & Tools in Technological System

AN EXPERIMENTAL INVESTIGATION OF THE MECHANICAL PROPERTIES OF FUSED FILAMENT FABRICATED NYLON-CARBON FIBER COMPOSITES

Ioannis T. Christodoulou — 2024-06-15

Additive Manufacturing (AM) is a rapidly growing field in both the researching and the industrial world, as it produces highly customized and geometrically complex objects. The most well-known AM technology for plastics is Fused Filament Fabrication (FFF), in which a thermoplastic filament is melted and extruded through a nozzle on the printing bed. A wide variety of printing parameters affect the quality of the printed objects, such as printing speed, infill density, infill pattern, build orientation, layer height, etc. In literature, there is already extended research of the impact of the printing parameters on the mechanical properties of the most common thermoplastics, such as ABS and PETG. However, the development of advanced thermoplastic materials, such as Nylon composites reinforced with carbon fibers (Nylon-CF), requires a further investigation of the effect of the printing parameters on those advanced composites. In the current study, an in-depth correlation of all the major printing parameters (infill pattern, infill density, dual line infill and printing speed) with all the major mechanical properties (tensile strength, compressive strength and bending strength) of Nylon-CF is carried out.

PRELIMINARY STUDY OF THE AREAL ROUGHNESS PARAMETERS IN 3D PRINTING OF WORKPIECES OF PLA MATERIAL

István Sztankovics — 2024-06-15

The field of production engineering is constantly expanding, as novel manufacturing procedures are being introduced and spread in the industrial environment. The creation of complex parts by the application of some kind of printing process is a relatively new method compared to the other traditional chip-removal processes. It can be applied in various fields, where the greatest advantage can be utilized, which is the lower restrictions on the geometry of finished parts. In this paper, the surfaces on 3D printed parts are being studied. The effect of the printing speed, layer height and nozzle temperature are analysed on the surface roughness of the experimental workpieces. The experimental setup plan is designed according to the full factorial design method. The results of this preliminary study are the general determination of the affecting factors on the surface roughness.

ANALYSIS OF THE ABBOTT-FIRESTONE CURVE ON A DIAMOND-BURNISHED SURFACE

Szilárd Smolnicki — 2024-06-15

In the research we provide a brief overview of the context of the topic, starting from the issues of energy efficiency and environmental awareness and sustainable development, through the positive properties of alternative forms of processing such as diamond burnishing, to the examination of the surface finish, which plays a key role in the relationship between surface quality and diamond burnishing. In the first chapter of this paper, the science of sustainable development, industrial ecology and its different systems models are presented, leading to the three pillars of sustainable development. In the same chapter, we touch on the relationship between energy- and eco-efficiency, their characteristics, recent research results and impacts. We present the dimensions and material quality of the test piece on which the tests were carried out. This will be followed by a description of the technological characteristics of the turning and diamond-burnishing processes. The characteristics and usefulness of the Abbott-Firestone curve are listed, and the improvement factors and K-coefficients are calculated. In the third section, experimental results are presented by examining the data of the Abbott-Firestone surface curves, which are presented using both the improvement factors and the K-coefficients to draw conclusions by examining the different technological parameters. We conclude our study by summarizing the results of our research.

ALUMINUM MATRIX COMPOSITES ALTERNATIVE FOR BRAKE ROTOR APPLICATIONS

Afraa Khattab — 2024-06-15

This literature overview examines the capacity of using aluminum matrix composites (AMCs) rather than conventional grey solid iron in brake rotor packages. Driven by the preference for lighter and more environmentally friendly vehicles, AMCs offer several benefits, including decreased weight, advanced thermal properties, superior put-on resistance, and an optimized breaking system. Studies have concluded that AMCs can gain weight reductions of up to 60% compared to cast iron, resulting in stepped-forward gas performance and automobile management. Besides exhibiting superior thermal conductivity and lower thermal enlargement, it results in better heat dissipation and a reduced danger of warping and cracking. The advantage of using ceramic reinforcements, which include SiC, Al2O3, and B4C, is that they can enhance the damage resistance of AMCs, leading to a longer service life for brake rotors. The review covers various elements of AMC brake rotor development, Starting with manufacturing strategies (stir casting, ultrasonic-assisted stir casting, and squeeze casting), which are powerful techniques for producing extremely good AMC rotors, then the thermal traits, which are so essential due to their thermal conductivity, thermal expansion, and heat dissipation in brake rotor overall performance, Finally, the tribological residences affect load, sliding pace, and floor roughness on the wear and friction of AMC rotors. Brake pad compatibility is so vital in breaking systems, that deciding on suitable brake pad materials, containing non-asbestos organic (NAO) pads, can optimize performance with AMC rotors. These traits can be computationally analysed by using finite element evaluation and different numerical methods to predict the thermal and mechanical behaviour of AMC brake rotors. The review emphasizes that AMCs maintain great promise as next-era manufacturing for brake rotors, offering a balance of weight reduction, stepped-forward thermal control, and more advantageous wear resistance. Further research and improvement are necessary to optimize fabric composition, production strategies, and brake pad compatibility to improve the capacity of AMCs in brake structures.

SPECIFIC ENERGY CAPACITY OF PROCESSING AND ENERGY EFFICIENCY FOR PROCESS OF GRINDING WITH WHEELS FROM SUPERHARD MATERIALS

Valerii Lavrinenko — 2024-06-15

The analysis of modern research shows that when evaluating the specific energy intensity of the abrasive processing process, one should pay attention not only to the indicators of grinding power and material removal rate, but also to the indicator of the wear of the abrasive tool, which we will show below for the grinding tool made of superhard materials. It is shown that the traditional method of estimating the specific energy capacity based on the ratio of the grinding power to the processing productivity does not provide an adequate solution, since with it the specific heat capacity of processing exceeds the specific heat capacity of melting of the processing material by almost an order of magnitude. Therefore, it is the application of a new approach to the assessment of the specific energy intensity of diamond grinding, taking into account the wear of the working layer of the diamond wheel, and makes it possible to estimate the indicators of the specific energy intensity of grinding and the energy efficiency coefficient. It has been proven that when estimating the specific energy capacity of grinding metal-ceramic composite materials consisting of a low-melting and refractory component, the latent heat capacity of melting of the low-melting component should be taken as the basis. It is shown that the plastic mode of grinding occurs precisely when the specific energy capacity of grinding, taking into account the wear of the wheel, becomes close to the specific heat capacity of melting of a brittle material.

LEVEREGING TECHNOLOGICAL HEREDITY TO INCREASE PRODUCTION EFFICIENCY OF FERROCERRAMIC PRODUCTS DURING FINAL MACHINING

Anatoliy Usov — 2024-06-15

The quality state of grinded surface of ferro ceramic products is formed under the influence of thermomechanical phenomena which occurs during final machining and depends on the technological conditions for workpiece procurement. The mathematical model was formulated to regulate and optimize thermomechanical processes during the acquisition of ferroceramic workpieces. This mathematical model describes thermomechanical processes during workpieces sintering. Thermomechanical processes have a direct influence on defects formation in the workpieces. Grinding can cause the appearance of burns, cracks, tensile stresses in the surface layers of the products. These defects can significantly spoil the quality of products during their operation. High thermal stress of diamond-abrasive processing brings thermophysical aspects as a dominating factor for quality characteristics of processed surface. Existing grinding methods for products made from ferrocerramic materials are not able to fully eliminate the defects in the surface layer. Such defects are inherited from preceding machining operations, particularly from workpiece procurement. Material structure itself is prone or defect occurrence due to micro-heterogeneities, packaging defects, dislocations, and structural transformations. Analysis of the thermomechanical processes that run inside the surface layer made it possible to formulate calculation dependencies for defining technological conditions for eliminating burns and cracks during grinding of ferrocerramic products. Device for automatic stabilization of thermomechanical characteristics that accompany grinding of ferrocerramic products. This is achieved through the selection of optimal technological conditions for machining of the products that have heredity inhomogeneities inside the surface layer. Thus, this approach helps to achieve maximum efficiency within required quality citeria.

FINITE ELEMENT ANALYSIS OF CHANGING OF STRESS CONDITION CAUSED BY DIAMOND BURNISHING

Viktoria Ferencsik — 2024-06-15

The article is aspected to the finite element modelling of stress in subsurface layer of aluminium alloy workpiece during diamond burnishing process. This cold forming process is a simple, cost-effective finishing method that can be used to improve surface integrity and provide compressive residual stress. Available with these, durability and quality enhancement of the components can be reached, but improperly chosen burnishing parameters can distort the efficiency of the plastic deformation process. In order to optimize this, a 2D FEM model is created including the real surface integrity of the workpiece which was measured with AltiSurf 520 surface roughness measuring device. The method is simulated using DEFORM-2D software, corresponding to the numerical values of burnishing parameters implemented in practice as well, thereby allowing a comparative analysis with the results of X-ray diffraction measurement.

INFLUENCE OF FEED RATE ON THE DYNAMIC PROPERTIES OF THIN-WALLED PART DURING END-MILLING

Sergei Dyadya — 2024-06-15

When selecting cutting modes for end-milling of thin-walled parts from hard-to-machine materials, their influence on machining stability must be considered. To do this, it is necessary to understand the types of vibrations that operate and the conditions under which they arise. Research has shown that different types of vibrations operate sequentially during cutting and only for a certain of time. During end-milling, forced and accompanying free oscillations operates due to the short duration of cutting. Their influence on the stability of the cutting process depends on the speed zone in which the milling takes place. The most unfavorable is the third speed zone of vibrations, where accompanying free vibrations of high intensity occur. Cutting speeds for machining parts from hard-to-machine materials fall precisely within this zone. The intensity of vibrations is influenced by the dynamic properties of the part. During end-milling of thin-walled parts, these properties are characterized by the amplitude and frequency of accompanying free vibrations, which exceed the natural frequency of the part's free vibrations. In other words, cutting modes alter the dynamic properties of the part. Some researchers focus on utilizing the damping properties of the feed. Therefore, the aim of this paper was to determine how the feed affects the dynamic properties of the part during cutting. A universal stand was used for the investigation, which allows for the creation of various dynamic characteristics of the processed sample and recording its motion laws during milling on an oscillogram. The research results showed that the feed, as an element of cutting modes, influences the dynamic properties of the part during cutting. It creates a variable layer that is being cut. Therefore, during the cutting time, the frequency and amplitude of accompanying free vibrations change during both up- and down milling. The feed affects the dynamic stiffness. Increasing the feed increases the dynamic stiffness of the part. This leads to a reduction in the amplitude of accompanying free vibrations during milling in the third speed zone of vibrations. The results presented in the article have practical significance for technologists in the aviation manufacturing industry. They help to better understand the physical processes occurring during milling and develop optimal processing strategies for thin-walled parts, which have high requirements for dimensional accuracy and surface quality.

COMPARISON OF CUTTING TOOL GEOMETRIES BASED ON CUTTING FORCES AND ROUGHNESS OF HARD TURNED SURFACES

Viktor Molnár — 2024-06-15

Surface quality and energy consumption are two widely studied topics of hard machining. Due to the increasing need of companies for new, more efficient materials, tools and procedures, their manufacturers or suppliers have to deliver innovative solutions from time to time. In this study the latest development of a hard turning insert manufacturer is used in comprehensive machining experiments to show how the new tool (a wiper insert) behaves compared to its standard counterpart. Based on surface roughness and machining force measurement and analysis, this efficiency is proved by quantitative results: the wiper geometry ensures significantly better surface quality, while the energy consumption of the used machine tool is considerably lower.

DETERMINATION OF THE SIZE OF MEDIUM GRANULES IN FREE ABRASIVE PROCESSING TECHNOLOGY AND THE SIZE OF THE RESERVOIR OF A MACHINE FOR VIBRATION PROCESSING OF PARTS

Andrii Mitsyk — 2024-06-15

It is noted that the process of vibration processing of parts is carried out by the relative movement and mutual pressure of granules of the medium and the parts being processed circulating in the oscillating reservoir. It is noted that the removal of defects from the surface of a part is carried out by the processes of microcutting and elastoplastic deformation. It is indicated that despite the effectiveness of vibration processing, its capabilities are limited to performing simple operations and have not been sufficiently studied. The effectiveness of vibration processing depends on a number of factors, among which the size of the medium granules and the size of the machine reservoir play a significant role. To determine these factors, the kinematics of the finishing and grinding process was considered, and the joint movement of the medium granule and the part was taken into account. The removal of microchips along the entire length of the machined surface during one period of oscillation of the machine reservoir and the damping properties of the material of the working medium used were also taken into account. It has been established that, depending on the shape of the part, its position and direction of movement in the reservoir, the angle of contact with the granules can vary from 0 to 90º. In this regard, cases of encounters between granules and parts are considered. It has been established that the unfavorable case of a meeting occurs at the right angle of their collision. It is concluded that the removal of microchips from the surface of parts is theoretically inversely proportional to the size of the medium granules. It has been determined that the increase in damping of the medium caused by a decrease in the size of the granules can be compensated by increasing the amplitude of the oscillations of the reservoir and the use of granules with a large specific gravity. The choice of granule size is also limited by the conditions of their access to the surfaces being treated, while the conditions for eliminating the possibility of granules jamming are met. It has been experimentally confirmed that the reservoir with a “U” – shaped cross-section turned out to be the best, due to the absence of stagnant zones in it. It has been established that as the cross-section of the reservoir increases, the productivity of the machine will decrease. Intensifying the process by increasing the amplitude is unacceptable, since this causes the appearance of deep defects on the treated surfaces. To increase processing efficiency, it is necessary to increase the volume of the reservoir by lengthening it, rather than increasing its cross-section.

INTERPRETATION WORKFLOW OF GEOMETRIC TOLERANCES

Balazs Mikó — 2024-06-15

The application of the principles of the geometric product specification (GPS) has increasing importance in the machining industry. The tolerancing process should harmonize the relationship between tolerancing, machining process, measuring and design requirements. The aim of the article is to present the interpretation process and the suggested workflow of geometric tolerances. The dimensional and geometric tolerances are compared, and some critical problems of geometric tolerancing are demonstrated by case studies.

IMPACT OF DYNAMIC HUMAN AND TECHNOLOGICAL RESOURCE COST ON LOT SIZE OPTIMIZATION

Tamás Bányai — 2024-06-15

The design methods of production systems have evolved significantly in recent decades. New methods have emerged that are capable of determining the optimal parameters of production systems operating in increasingly complex environments. The two best known methods for lot sizing problems are the Wagner-Whitin algorithm and the Silver-Meal heuristics. The original versions of these two methods are only suitable for solving simple lot sizing problems, but there are several complex mutations of these methods that allow solving complex lot sizing problems. In the present research, the author presents a modified Wagner-Whitin algorithm that is suitable for solving the lot sizing problem and also for investigating the impact of dynamically changing resource costs. The proposed method is validated through case studies. The case studies demonstrate that the dynamic nature of cost of human resources and technological resources has a significant impact on the solution of lot sizing problems.

MANUFACTURING SYSTEMS USED IN THE SHIPBUILDING INDUSTRY FROM YEARS 2000 UP TO NOWADAYS

György Czifra — 2024-06-15

The continuous growth in demands for product quality and their utility properties in today's competitive environment places increased requirements on activities ranging from pre-production stages to sales completion. From these facts, it is evident that special attention must be paid to material selection, product design, and the construction of individual components, as well as the technologies used in their production and processing. Achieving high technical parameters for products while simultaneously optimizing the cost/performance or cost/utility value ratio compels designers and engineers to explore new progressive materials with high mechanical, chemical, and physical properties. They must also consider technologies that ensure efficient and precise manufacturing.

IMPACT OF QUANTITY DISCOUNT ON PURCHASING COSTS IN BLENDING TECHNOLOGIES

Ágota Bányai — 2024-06-15

Blending technologies are important in many sectors of industry, but are most prevalent in the chemical and food industries. They are playing an increasingly important role in the world economy despite the spread of electromobility. Nowadays, in addition to the technological aspects, there is a growing need to look at the logistical aspects, as logistics related costs account for a significant part of the cost of blending technologies. In this research work, the results of the analysis of the impact of quantity discounts, an important aspect of procurement activities related to blending technologies, are presented. A mathematical model is presented that can be used to investigate the impact of quantity discounts of components on profit and product quality. Based on scenario analyses carried out based on the mathematical model, it is demonstrated that the quantity discount can have a significant impact not only on total cost and profit, but also on the quality of the finished blended product.