The injection molding process is largely applied to obtain plastic parts. The problem of finding ... more The injection molding process is largely applied to obtain plastic parts. The problem of finding a simple equipment able to allow the study of the injection process was addressed in the research presented in this paper. Aiming to solve the problem, the main requests valid for the proposed equipment were formulated. Considering some possible versions of the equipment subassemblies, the ideas diagram method and the method of imposed decision were applied to select the most convenient version of the injection equipment. As a result, a constructive solution for a simple injection molding equipment that could be used to develop some experimental researches was identified.
The strength of a joint between the ends of one or more strips can be improved by making the cont... more The strength of a joint between the ends of one or more strips can be improved by making the contours of the joint into the shape of either the Greek letter omega or of a dovetail. From the point of view of industrial practice, it is of interest to study the behavior of these joints under stretching demands. The emergence and development of additive manufacturing processes for parts made of polymeric materials has led to the idea of conducting experimental tests to highlight the behavior of omega and dovetail-type joints during the tensile test. For the tensile testing of some test samples in which omega and dovetail joints were used, a Taguchi array of type L18 was employed, with eight independent variables, one variable with a two-level variation, and seven variables with variations on three levels. As independent variables, the type of joint, the couple of polymer materials used to make the two components of the joint, some characteristic dimensions of the joint contours, and som...
For reduced mechanical stress, some chains with links made of metallic materials could be replace... more For reduced mechanical stress, some chains with links made of metallic materials could be replaced by chains made of polymeric materials. A lower weight and a higher corrosion resistance would characterize such chains. From this point of view, research on the behavior of chain links made of polymeric materials under the action of tensile stresses can become important. Modeling by the finite element method highlighted some specific aspects of the behavior of a chain link subjected to tensile stresses. Later, we resorted to the manufacture by 3D printing of some chain links from four distinct polymeric materials, with the modification of the size of the chain link and, respectively, of the values of some of the input factors in the 3D printing process. The tensile strength of the chain links was determined using specialized equipment. The experimental results were processed mathematically to determine some empirical mathematical models that highlight the influence of the values of the...
One of the processes by which hardening of the surface layer and diminishing the heights of the s... more One of the processes by which hardening of the surface layer and diminishing the heights of the surface roughness occur in the case of steel parts is vibroburnishing. The analysis of the conditions of using the vibroburnishing process of the cylindrical surfaces showed that the use of lubrication could influence the heights of the asperities resulting from the processing. The problem of conducting experimental research was formulated to highlight the intensity of the influence exerted by some input factors in the vibroburnishing process on the roughness of the processed surfaces, evaluated by using the roughness parameter Ra. An experimental program was designed aiming to use different values of ball diameter, ball pressing force, and initial roughness, in conditions of dry vibroburnishing and using lubricating oil, respectively. The experimental results were processed using a software based on the least-squares method. The determined empirical mathematical models showed that, under the conditions in which the experimental tests were performed, the strongest influence on the value of the roughness parameter Ra is exerted by the initial surface roughness, followed by the size of the ball pressing force on the surface and by the ball diameter, the latter exerting very little influence. It was confirmed that the presence of a lubricant in the processing area results in a decrease in the size of the roughness parameter Ra, compared to the situation where such a lubricant is not used.
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section
The assessment of the ability of polymeric materials to transmit heat is of interest both from th... more The assessment of the ability of polymeric materials to transmit heat is of interest both from the point of view of ensuring maximum thermal transfer and thermal insulation. A simple equipment was designed and materialized for studying thermal transfer in polylactic acid rods made by 3D printing. The results of some experimental tests carried out using the equipment were mathematically processed, determining empirical mathematical models of the second-degree polygon type and a power-type function. The analysis of the empirical mathematical models and the graphic representations made on their basis revealed a decrease in temperature with the increase of the distance from the heated end of the cylindrical rod type test sample and the increase in temperature along the rod until the state of thermal equilibrium is reached.
The paper aims to highlight the significance and place of information-seeking in finding improved... more The paper aims to highlight the significance and place of information-seeking in finding improved solutions in the design of innovative products. The observation method was used to identify a way to increase the efficiency of searching for information needed when pursuing a creative solution to a design problem. The study was based on the experience gained in professional activities in higher education for industrial engineering and in the classes held for two academic subjects, when students’ creativity was stimulated, including in the search for information. One conclusion is that an experienced designer or researcher should make sketches and notes immediately after formulating the design objective. In this way, the possible inhibitory influence exerted by the results of a deep search for information could be avoided. In the case of a novice designer, it may be necessary to have a minimum collection of general information in the design topic field to familiarize the designer more ...
Wire electrical discharge machining (WEDM) is a process that is used when it is necessary to manu... more Wire electrical discharge machining (WEDM) is a process that is used when it is necessary to manufacture small-width slots with a micrometer accuracy or to precisely detach parts with complex contours from metal workpieces in the form of sheets or plates. The fact that the wire electrode rests only in the working zone in two of its guides allows it to achieve micrometric oscillations, leading to the generation of an error from the flat shape of the slot surfaces that gradually develops into the workpiece. The slot widths are influenced by several factors, such as the workpiece thickness, pulse-on time, pulse-off time, the wire tension force, the current, and the wire movement speed along its axis. Some theoretical assumptions about the behavior of the wire electrode were first considered. An experimental research plan was then designed to obtain additional information on the influence of the mentioned factors on the slot width in different positions of the cross-section through the ...
The thermal properties of parts obtained by 3D printing from polymeric materials may be interesti... more The thermal properties of parts obtained by 3D printing from polymeric materials may be interesting in certain practical situations. One of these thermal properties is the ability of a material to expand as the temperature rises or shrink when the temperature drops. A test experiment device was designed based on the thermal expansion or negative thermal expansion of spiral test samples, made by 3D printing of polymeric materials to investigate the behavior of some polymeric materials in terms of thermal expansion or contraction. A spiral test sample was placed on an aluminum alloy plate in a spiral groove. A finite element modeling highlighted the possibility that areas of the plate and the spiral test sample have different temperatures, which means thermal expansions or contractions have different values in the spiral areas. A global experimental evaluation of four spiral test samples was made by 3D printing four distinct polymeric materials: styrene-butadiene acrylonitrile, polyet...
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section
There are situations where parts manufactured by 3D printing processes must have a high abrasion ... more There are situations where parts manufactured by 3D printing processes must have a high abrasion resistance. To conduct experimental research on this subject, relatively simple test equipment for abrasive wear of pin-on-disk type was designed and materialized. The test pieces from the research material were pressed with known forces on the surface of a rotating abrasive paper disk. The test pieces were made of polyethylene terephthalate PET and polyethylene terephthalate carbon fiber reinforced PET CF15. As output parameters, the speed of decreasing the mass and the length of the test piece were used, respectively, for predetermined test durations. An experimental Taguchi L8 program was used, with 7 independent variables at two levels of variation. The experimental results were mathematically processed determined empirical mathematical models of the power function type. It was found that the strongest influence on the values of the output parameters was exerted by the average travel...
A better understanding of heat transfer through materials used for 3D-printed parts could lead to... more A better understanding of heat transfer through materials used for 3D-printed parts could lead to an extension and an optimization of their use. A topic of interest could be analyzing temperature variation in these materials during cooling processes. Experimental research and equipment were designed to obtain additional information on the surface temperature decrease when the opposite wall surface is exposed to a freezing temperature. Experimental tests were performed on samples made of polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). An experimental Taguchi L8 program was used, with seven independent variables at two levels of variation. The experimental data analysis with specialized software based on the least-squares method identified a mathematical model of first-degree polynomial type. The coefficients for each input factor involved provide information on the magnitude and trend of the considered output parameter when the input factors’ values change. It was fo...
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section, 2021
The use of electromechanical devices in many areas has led to the need to solve problems related ... more The use of electromechanical devices in many areas has led to the need to solve problems related to their proper functioning and the possibility that some external factors may affect their operation. The purpose of the developed research was to design and materialize a solution to test the operation of the computer hard disk as an electromechanical device. The systemic analysis method was used to highlight the factors capable of influencing the operation of a computer’s hard disk. The components of a hard disk performance testing equipment were identified to evaluate the operation of the hard disk at the variation of some input factors. An enclosure solution was subsequently established and implemented using the idea diagram method to evaluate the functioning of the hard disk when changing the values of some input factors capable of affecting the intensity of the process of losing the functional qualities of the hard disk.
Different processing methods can change the physical–mechanical properties and the microgeometry ... more Different processing methods can change the physical–mechanical properties and the microgeometry of the surfaces made by such processes. In turn, such microchanges may affect the tribological characteristics of the surface layer. The purpose of this research was to study the tribological behavior of a test piece surfaces analyzing the changes on the values of the coefficient of friction and loss of mass that appear in time. The surfaces subjected to experimental research were previously obtained by turning, grinding, ball burnishing, and vibroburnishing. The experimental research was performed using a device adaptable to a universal lathe. Mathematical processing of the experimental results led to the establishment of power-type function empirical models that highlight the intensity of the influence exerted by the pressure and duration of the test on the values of the output parameters. It was found that the best results were obtained in the case of applying ball vibroburnishing as ...
IOP Conference Series: Materials Science and Engineering, 2020
The ball vibroburnishing is a processing method based on the plastic deformation of the workpiece... more The ball vibroburnishing is a processing method based on the plastic deformation of the workpiece surface layer, as a result of a vibration movement achieved by the ball pressed with a known force on the workpiece surface. The surface obtained by ball vibroburnishing includes grooves with different directions and partially overlapped. To know better the influence exerted by the ball vibroburnishing conditions on the main dimensional characteristics of the grooves, an experimental research was designed and materialized. As the process input factors, the diameter of the ball, the force, and the workpiece rotation speed were used. The depth and width of the groves generated by the moving balls on the workpiece surface layer were measured. By mathematical processing of the experimental results, empirical mathematical models were determined. These models highlight the intensity of the influence exerted by the ball vibroburnishing process input factors on the main dimensions of the grooves.
The form of the outer and inner surfaces of hollow spherical parts determines the developments of... more The form of the outer and inner surfaces of hollow spherical parts determines the developments of some particular categories of efforts during the compression tests. The overall purpose of the research presented in this paper was to study the behaviour of the hollow spherical parts under axial compression. The PLA hollow spherical parts were obtained by 3D printing and using distinct values for certain process input factors. The finite element method was used to theoretically investigate the behaviour of the parts and it highlighted the total plastic deformation of the test pieces. To experimentally verify the theoretical considerations, an L9 Taguchi orthogonal design was performed. The empirical mathematical model thus determined highlighted the stronger influence exerted by the printing plate temperature, printing speed, and part wall thickness.
One of the processes used to separate parts from plate-type workpiece is laser beam cutting. The ... more One of the processes used to separate parts from plate-type workpiece is laser beam cutting. The evaluation of the quality of the machined surfaces can be performed by taking into account the influence exerted by some input factors in the cutting process on the width of the slot and on the roughness of the surfaces generated by the laser beam cutting process. The paper presents the results of experimental research performed on a steel plate type workpiece. The objective pursued was to reveal the influence exerted by several input factors of the laser beam cutting process on some output parameters of this process. Empirical mathematical models corresponding to the output parameters taken into account were established. It was possible to order the input factors in the process by taking into consideration their weight in the values of the output parameters.
3D printing is a process that has become widely used in recent years, allowing the production of ... more 3D printing is a process that has become widely used in recent years, allowing the production of parts with relatively complicated shapes from metallic and non-metallic materials. In some cases, it is challenging to evaluate the ability of 3D printers to make fine details of parts. For such an assessment, the printing of samples showing intersections of surfaces with low angle values was considered. An experimental plan was designed and materialized to highlight the influence of different factors, such as the thickness of the deposited material layer, the printing speed, the cooling and filling conditions of the 3D-printed part, and the thickness of the sample. Samples using areas in the form of isosceles triangles with constant height or bases with the same length, respectively, were used. The mathematical processing of the experimental results allowed the determination of empirical mathematical models of the power-function type. It allowed the detection of both the direction of ac...
The total machining error includes some distinct errors summed up by following certain rules. One... more The total machining error includes some distinct errors summed up by following certain rules. One of these errors is the workpiece locating error, which occurs when the workpiece reference base does not match the workpiece locating surface. The paper analyses different definitions of positioning error, as they were proposed by different researchers or groups of researchers and presents an application valid in the case of turning a cylindrical workpiece with locating between the centers. A definition of locating error that takes into account the total differential of the size of the vector that joins the orientation surface with an element of the fixture was preferred. A fixture version was considered to ensure the locating and clamping of the workpiece on the lathes, with workpiece locating between the centers. This fixture uses a mandrel with a sliding center and an elastic collet.
Wire electrical discharge machining has appeared mainly in response to the need for detachment wi... more Wire electrical discharge machining has appeared mainly in response to the need for detachment with sufficiently high accuracy of parts of plate-type workpieces. The improvements introduced later allowed the extension of this machining technology to obtain more complex ruled surfaces with increasingly high requirements regarding the quality of the machined surfaces and the productivity of the wire electrical discharge machining process. Therefore, it was normal for researchers to be interested in developing more and more in-depth investigations into the various aspects of wire electrical discharge machining. These studies focused first on improving the machining equipment, wire electrodes, and the devices used to position the clamping of a wire electrode and workpiece. A second objective pursued was determining the most suitable conditions for developing the machining process for certain proper situations. As output parameters, the machining productivity, the accuracy, and roughness...
Bearing bushing parts are used to support other rotating moving parts. When these bearing bushing... more Bearing bushing parts are used to support other rotating moving parts. When these bearing bushings are made of bronze, their inner cylindrical surfaces can be finished by turning. The problem addressed in this paper was that of identifying an alternative for finishing by turning the inner cylindrical surfaces of bearing bushing parts by taking into account the specific sustainability requirements. Three alternatives for finishing turning the inner cylindrical surfaces of bearing bushings have been identified. The selection of the alternative that ensures the highest probability that the diameter of the machined surface is included in the prescribed tolerance field was made first by using the second axiom of the axiomatic design. It was thus observed that for the initial turning alternative, the probability of success assessed by using a normal distribution is 77.2%, while for the third alternative, which will correspond to a Maxwell–Boltzmann distribution, the probability of success...
The injection molding process is largely applied to obtain plastic parts. The problem of finding ... more The injection molding process is largely applied to obtain plastic parts. The problem of finding a simple equipment able to allow the study of the injection process was addressed in the research presented in this paper. Aiming to solve the problem, the main requests valid for the proposed equipment were formulated. Considering some possible versions of the equipment subassemblies, the ideas diagram method and the method of imposed decision were applied to select the most convenient version of the injection equipment. As a result, a constructive solution for a simple injection molding equipment that could be used to develop some experimental researches was identified.
The strength of a joint between the ends of one or more strips can be improved by making the cont... more The strength of a joint between the ends of one or more strips can be improved by making the contours of the joint into the shape of either the Greek letter omega or of a dovetail. From the point of view of industrial practice, it is of interest to study the behavior of these joints under stretching demands. The emergence and development of additive manufacturing processes for parts made of polymeric materials has led to the idea of conducting experimental tests to highlight the behavior of omega and dovetail-type joints during the tensile test. For the tensile testing of some test samples in which omega and dovetail joints were used, a Taguchi array of type L18 was employed, with eight independent variables, one variable with a two-level variation, and seven variables with variations on three levels. As independent variables, the type of joint, the couple of polymer materials used to make the two components of the joint, some characteristic dimensions of the joint contours, and som...
For reduced mechanical stress, some chains with links made of metallic materials could be replace... more For reduced mechanical stress, some chains with links made of metallic materials could be replaced by chains made of polymeric materials. A lower weight and a higher corrosion resistance would characterize such chains. From this point of view, research on the behavior of chain links made of polymeric materials under the action of tensile stresses can become important. Modeling by the finite element method highlighted some specific aspects of the behavior of a chain link subjected to tensile stresses. Later, we resorted to the manufacture by 3D printing of some chain links from four distinct polymeric materials, with the modification of the size of the chain link and, respectively, of the values of some of the input factors in the 3D printing process. The tensile strength of the chain links was determined using specialized equipment. The experimental results were processed mathematically to determine some empirical mathematical models that highlight the influence of the values of the...
One of the processes by which hardening of the surface layer and diminishing the heights of the s... more One of the processes by which hardening of the surface layer and diminishing the heights of the surface roughness occur in the case of steel parts is vibroburnishing. The analysis of the conditions of using the vibroburnishing process of the cylindrical surfaces showed that the use of lubrication could influence the heights of the asperities resulting from the processing. The problem of conducting experimental research was formulated to highlight the intensity of the influence exerted by some input factors in the vibroburnishing process on the roughness of the processed surfaces, evaluated by using the roughness parameter Ra. An experimental program was designed aiming to use different values of ball diameter, ball pressing force, and initial roughness, in conditions of dry vibroburnishing and using lubricating oil, respectively. The experimental results were processed using a software based on the least-squares method. The determined empirical mathematical models showed that, under the conditions in which the experimental tests were performed, the strongest influence on the value of the roughness parameter Ra is exerted by the initial surface roughness, followed by the size of the ball pressing force on the surface and by the ball diameter, the latter exerting very little influence. It was confirmed that the presence of a lubricant in the processing area results in a decrease in the size of the roughness parameter Ra, compared to the situation where such a lubricant is not used.
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section
The assessment of the ability of polymeric materials to transmit heat is of interest both from th... more The assessment of the ability of polymeric materials to transmit heat is of interest both from the point of view of ensuring maximum thermal transfer and thermal insulation. A simple equipment was designed and materialized for studying thermal transfer in polylactic acid rods made by 3D printing. The results of some experimental tests carried out using the equipment were mathematically processed, determining empirical mathematical models of the second-degree polygon type and a power-type function. The analysis of the empirical mathematical models and the graphic representations made on their basis revealed a decrease in temperature with the increase of the distance from the heated end of the cylindrical rod type test sample and the increase in temperature along the rod until the state of thermal equilibrium is reached.
The paper aims to highlight the significance and place of information-seeking in finding improved... more The paper aims to highlight the significance and place of information-seeking in finding improved solutions in the design of innovative products. The observation method was used to identify a way to increase the efficiency of searching for information needed when pursuing a creative solution to a design problem. The study was based on the experience gained in professional activities in higher education for industrial engineering and in the classes held for two academic subjects, when students’ creativity was stimulated, including in the search for information. One conclusion is that an experienced designer or researcher should make sketches and notes immediately after formulating the design objective. In this way, the possible inhibitory influence exerted by the results of a deep search for information could be avoided. In the case of a novice designer, it may be necessary to have a minimum collection of general information in the design topic field to familiarize the designer more ...
Wire electrical discharge machining (WEDM) is a process that is used when it is necessary to manu... more Wire electrical discharge machining (WEDM) is a process that is used when it is necessary to manufacture small-width slots with a micrometer accuracy or to precisely detach parts with complex contours from metal workpieces in the form of sheets or plates. The fact that the wire electrode rests only in the working zone in two of its guides allows it to achieve micrometric oscillations, leading to the generation of an error from the flat shape of the slot surfaces that gradually develops into the workpiece. The slot widths are influenced by several factors, such as the workpiece thickness, pulse-on time, pulse-off time, the wire tension force, the current, and the wire movement speed along its axis. Some theoretical assumptions about the behavior of the wire electrode were first considered. An experimental research plan was then designed to obtain additional information on the influence of the mentioned factors on the slot width in different positions of the cross-section through the ...
The thermal properties of parts obtained by 3D printing from polymeric materials may be interesti... more The thermal properties of parts obtained by 3D printing from polymeric materials may be interesting in certain practical situations. One of these thermal properties is the ability of a material to expand as the temperature rises or shrink when the temperature drops. A test experiment device was designed based on the thermal expansion or negative thermal expansion of spiral test samples, made by 3D printing of polymeric materials to investigate the behavior of some polymeric materials in terms of thermal expansion or contraction. A spiral test sample was placed on an aluminum alloy plate in a spiral groove. A finite element modeling highlighted the possibility that areas of the plate and the spiral test sample have different temperatures, which means thermal expansions or contractions have different values in the spiral areas. A global experimental evaluation of four spiral test samples was made by 3D printing four distinct polymeric materials: styrene-butadiene acrylonitrile, polyet...
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section
There are situations where parts manufactured by 3D printing processes must have a high abrasion ... more There are situations where parts manufactured by 3D printing processes must have a high abrasion resistance. To conduct experimental research on this subject, relatively simple test equipment for abrasive wear of pin-on-disk type was designed and materialized. The test pieces from the research material were pressed with known forces on the surface of a rotating abrasive paper disk. The test pieces were made of polyethylene terephthalate PET and polyethylene terephthalate carbon fiber reinforced PET CF15. As output parameters, the speed of decreasing the mass and the length of the test piece were used, respectively, for predetermined test durations. An experimental Taguchi L8 program was used, with 7 independent variables at two levels of variation. The experimental results were mathematically processed determined empirical mathematical models of the power function type. It was found that the strongest influence on the values of the output parameters was exerted by the average travel...
A better understanding of heat transfer through materials used for 3D-printed parts could lead to... more A better understanding of heat transfer through materials used for 3D-printed parts could lead to an extension and an optimization of their use. A topic of interest could be analyzing temperature variation in these materials during cooling processes. Experimental research and equipment were designed to obtain additional information on the surface temperature decrease when the opposite wall surface is exposed to a freezing temperature. Experimental tests were performed on samples made of polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). An experimental Taguchi L8 program was used, with seven independent variables at two levels of variation. The experimental data analysis with specialized software based on the least-squares method identified a mathematical model of first-degree polynomial type. The coefficients for each input factor involved provide information on the magnitude and trend of the considered output parameter when the input factors’ values change. It was fo...
Bulletin of the Polytechnic Institute of Iași. Machine constructions Section, 2021
The use of electromechanical devices in many areas has led to the need to solve problems related ... more The use of electromechanical devices in many areas has led to the need to solve problems related to their proper functioning and the possibility that some external factors may affect their operation. The purpose of the developed research was to design and materialize a solution to test the operation of the computer hard disk as an electromechanical device. The systemic analysis method was used to highlight the factors capable of influencing the operation of a computer’s hard disk. The components of a hard disk performance testing equipment were identified to evaluate the operation of the hard disk at the variation of some input factors. An enclosure solution was subsequently established and implemented using the idea diagram method to evaluate the functioning of the hard disk when changing the values of some input factors capable of affecting the intensity of the process of losing the functional qualities of the hard disk.
Different processing methods can change the physical–mechanical properties and the microgeometry ... more Different processing methods can change the physical–mechanical properties and the microgeometry of the surfaces made by such processes. In turn, such microchanges may affect the tribological characteristics of the surface layer. The purpose of this research was to study the tribological behavior of a test piece surfaces analyzing the changes on the values of the coefficient of friction and loss of mass that appear in time. The surfaces subjected to experimental research were previously obtained by turning, grinding, ball burnishing, and vibroburnishing. The experimental research was performed using a device adaptable to a universal lathe. Mathematical processing of the experimental results led to the establishment of power-type function empirical models that highlight the intensity of the influence exerted by the pressure and duration of the test on the values of the output parameters. It was found that the best results were obtained in the case of applying ball vibroburnishing as ...
IOP Conference Series: Materials Science and Engineering, 2020
The ball vibroburnishing is a processing method based on the plastic deformation of the workpiece... more The ball vibroburnishing is a processing method based on the plastic deformation of the workpiece surface layer, as a result of a vibration movement achieved by the ball pressed with a known force on the workpiece surface. The surface obtained by ball vibroburnishing includes grooves with different directions and partially overlapped. To know better the influence exerted by the ball vibroburnishing conditions on the main dimensional characteristics of the grooves, an experimental research was designed and materialized. As the process input factors, the diameter of the ball, the force, and the workpiece rotation speed were used. The depth and width of the groves generated by the moving balls on the workpiece surface layer were measured. By mathematical processing of the experimental results, empirical mathematical models were determined. These models highlight the intensity of the influence exerted by the ball vibroburnishing process input factors on the main dimensions of the grooves.
The form of the outer and inner surfaces of hollow spherical parts determines the developments of... more The form of the outer and inner surfaces of hollow spherical parts determines the developments of some particular categories of efforts during the compression tests. The overall purpose of the research presented in this paper was to study the behaviour of the hollow spherical parts under axial compression. The PLA hollow spherical parts were obtained by 3D printing and using distinct values for certain process input factors. The finite element method was used to theoretically investigate the behaviour of the parts and it highlighted the total plastic deformation of the test pieces. To experimentally verify the theoretical considerations, an L9 Taguchi orthogonal design was performed. The empirical mathematical model thus determined highlighted the stronger influence exerted by the printing plate temperature, printing speed, and part wall thickness.
One of the processes used to separate parts from plate-type workpiece is laser beam cutting. The ... more One of the processes used to separate parts from plate-type workpiece is laser beam cutting. The evaluation of the quality of the machined surfaces can be performed by taking into account the influence exerted by some input factors in the cutting process on the width of the slot and on the roughness of the surfaces generated by the laser beam cutting process. The paper presents the results of experimental research performed on a steel plate type workpiece. The objective pursued was to reveal the influence exerted by several input factors of the laser beam cutting process on some output parameters of this process. Empirical mathematical models corresponding to the output parameters taken into account were established. It was possible to order the input factors in the process by taking into consideration their weight in the values of the output parameters.
3D printing is a process that has become widely used in recent years, allowing the production of ... more 3D printing is a process that has become widely used in recent years, allowing the production of parts with relatively complicated shapes from metallic and non-metallic materials. In some cases, it is challenging to evaluate the ability of 3D printers to make fine details of parts. For such an assessment, the printing of samples showing intersections of surfaces with low angle values was considered. An experimental plan was designed and materialized to highlight the influence of different factors, such as the thickness of the deposited material layer, the printing speed, the cooling and filling conditions of the 3D-printed part, and the thickness of the sample. Samples using areas in the form of isosceles triangles with constant height or bases with the same length, respectively, were used. The mathematical processing of the experimental results allowed the determination of empirical mathematical models of the power-function type. It allowed the detection of both the direction of ac...
The total machining error includes some distinct errors summed up by following certain rules. One... more The total machining error includes some distinct errors summed up by following certain rules. One of these errors is the workpiece locating error, which occurs when the workpiece reference base does not match the workpiece locating surface. The paper analyses different definitions of positioning error, as they were proposed by different researchers or groups of researchers and presents an application valid in the case of turning a cylindrical workpiece with locating between the centers. A definition of locating error that takes into account the total differential of the size of the vector that joins the orientation surface with an element of the fixture was preferred. A fixture version was considered to ensure the locating and clamping of the workpiece on the lathes, with workpiece locating between the centers. This fixture uses a mandrel with a sliding center and an elastic collet.
Wire electrical discharge machining has appeared mainly in response to the need for detachment wi... more Wire electrical discharge machining has appeared mainly in response to the need for detachment with sufficiently high accuracy of parts of plate-type workpieces. The improvements introduced later allowed the extension of this machining technology to obtain more complex ruled surfaces with increasingly high requirements regarding the quality of the machined surfaces and the productivity of the wire electrical discharge machining process. Therefore, it was normal for researchers to be interested in developing more and more in-depth investigations into the various aspects of wire electrical discharge machining. These studies focused first on improving the machining equipment, wire electrodes, and the devices used to position the clamping of a wire electrode and workpiece. A second objective pursued was determining the most suitable conditions for developing the machining process for certain proper situations. As output parameters, the machining productivity, the accuracy, and roughness...
Bearing bushing parts are used to support other rotating moving parts. When these bearing bushing... more Bearing bushing parts are used to support other rotating moving parts. When these bearing bushings are made of bronze, their inner cylindrical surfaces can be finished by turning. The problem addressed in this paper was that of identifying an alternative for finishing by turning the inner cylindrical surfaces of bearing bushing parts by taking into account the specific sustainability requirements. Three alternatives for finishing turning the inner cylindrical surfaces of bearing bushings have been identified. The selection of the alternative that ensures the highest probability that the diameter of the machined surface is included in the prescribed tolerance field was made first by using the second axiom of the axiomatic design. It was thus observed that for the initial turning alternative, the probability of success assessed by using a normal distribution is 77.2%, while for the third alternative, which will correspond to a Maxwell–Boltzmann distribution, the probability of success...
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Papers by Adelina Hrituc