Gyula Mátyási - Academia.edu (original) (raw)

Papers by Gyula Mátyási

In computer-aided manufacturing systems a number of methods have been published for milling path ... more In computer-aided manufacturing systems a number of methods have been published for milling path generation considering different geometric requirements and conditions determined by specific environments. In this paper we propose a method for the computation of the moving direction of the cutting tool in 3-axis milling considering the local features of the surface. Our method combines two geometric approaches. Computations are presented on analytical surfaces and on triangle meshes.

Manufacturing Technology, 2015

The industrial use of aluminium alloys has significantly increased in the last decades. Most mach... more The industrial use of aluminium alloys has significantly increased in the last decades. Most machined parts are produced by cutting. Therefore, research in this field is quite important nowadays. Surface roughness is an extremely important quality parameter of a product, such as geometrical sizes and their tolerance. The authors in this article analysed the machinability of die-cast aluminium alloys with silicon often used in the industry. The turning experiments were made with different diamond tools edge geometry. The surface roughness obtained during turning was analysed in detail. Phenomenological models were created with which the surface roughness producing ability of the examined tools can be estimated in technological design.

Fiatal Műszakiak Tudományos Ülésszaka, 2014

The knowledge of the properties of the process of cutting aluminium is getting more and more impo... more The knowledge of the properties of the process of cutting aluminium is getting more and more important nowadays, particularly because of the large number of fields where aluminium alloys can be used, such as in automotive, war and aerospace industries. One of the most widespread index numbers used for measuring surface quality are Ra and Rz values. In this article, the authors examined the cutting capacities of aluminium parts (reinforced with silicon) with the help of design of experiment (DOE). The investigations were carried out with different edge-geometry diamond tools and conclusions were drawn about cutting abilities of the diamond tools used.

Fiatal Műszakiak Tudományos Ülésszaka, 2012

Recently industrial applications of hypereutectic cast aluminium parts has greatly increased. Thi... more Recently industrial applications of hypereutectic cast aluminium parts has greatly increased. This is partly related to their advantegous properties however they are difficult to machine. The paper deals with the environmentalfriendly fine turning of hypereutectic cast aluminium cylinders. In the experiments several PCD tools were used. The surfaces roughness capacity of individual tools, the topological map of the machining and the expected tribological behaviour of turned parts will also be presented. The deteriorating factors of chip formation is examined in relation to the conditions of their formation, their effects and the ways of their avoidence.

Fiatal Műszakiak Tudományos Ülésszaka, 2013

The machining of aluminium parts has been made more important in recent years and decades. The al... more The machining of aluminium parts has been made more important in recent years and decades. The aluminium alloys are used by the automotive, aero and war industrys increasingly because of their numerous good advantageous mechanical and chemical properties. The most often used cut types are the so-called AlMgSi alloys, of which the most widespread are the reinforced silicon alloys. The surface roughness capacity of a diamond tool was examined by design of experiment. Reduced empirical equation was chosen between the cutting paramters and the measured roughness. The optimal area of cutting parameters was defined.

International Journal of Machining and Machinability of Materials, 2017

In cutting research, the determination of the spatial force system of cutting processes is extrem... more In cutting research, the determination of the spatial force system of cutting processes is extremely important. Therefore, the forces generated need to be measured with high precision. In this paper, the development of a special three-component dynamometer system is presented for the measurement of small forces (0…100 N) in three directions during fine cutting, with a precision of 0.1 N. The designed dynamometer employs a piezo-electric cell and can easily be mounted on the tool post with only small modifications to the tool holder. The setup was calibrated for sensitivity, static load and range. By using error functions, the relative error in the measurement of force is kept below 1.5%.

ANZIAM Journal, 2014

Machining of aluminium parts has become particularly important in recent years. Surface roughness... more Machining of aluminium parts has become particularly important in recent years. Surface roughness measurements are essential in the characterization of the surface integrity of a machined surface. To examine the effect of cutting parameters on surface roughness thoroughly, a huge number of experiments are needed, depending on the number of parameters. By utilizing the method of design of experiments, the number of experiments is reduced, as determined by the effects of the parameters. If linear effects of cutting parameters are considered, then fractional factorial design is sufficient, but to take into consideration the interactions between the factors and the quadratic terms, the response surface method has to be utilized.

Procedia CIRP, 2016

In current manufacturing the burr-free edges of the workpieces are required after machining. Subs... more In current manufacturing the burr-free edges of the workpieces are required after machining. Subsequently removing the burrs from the edges of the workpieces increases the cost and time of production. This is the reason why manufacturers try to avoid and reduce the burr. In face milling a possible solution to reduce the burr is the controlling of the exit angle. The exact value of the exit angle can be determined only numerically, however, if the path of the tool edge is approximated with a circle, then the approximation error can be calculated exactly. The chip thickness changes together with the exit angle when using constant feed rate, so the effect of chip thickness has to be considered as well. The exact value of chip thickness can also be determined only numerically, but there are many known approximations that can be applied in practice for the cases when small feed rates are used. An optimal range of exit angle can be estimated with an experiment that is presented in the paper. For circle and line contour elements the path of the tool centre can be determined exactly, which meet the criteria of a given exit angle. The two paths of tool centre belonging to two different exit angles form a closed area. If the tool centre during machining moves inside of this area, then the exit angle remains in the specified range. Depending on the complexity of the workpiece the path of tool centre cannot be always determined for a given exit angle criteria. The paper presents several paths of tool centre belonging to various exit angles for a special workpiece geometry that was used for the experiments. The results of the experiments are presented, which illustrate the efficiency of the method.

UPB Scientific Bulletin, Series D: Mechanical Engineering

Precise knowledge of the machinability of aluminium is more and more important nowadays because a... more Precise knowledge of the machinability of aluminium is more and more important nowadays because aluminium alloys are used by many industries (e.g. the automotive, aerospace and defence industries) and therefore their importance is growing. Two of the most common indices of surface quality are Ra (average surface roughness) and Rz (surface height). However, these surface roughness parameters generally used in the industry do not properly characterise the expected behaviour of machined surfaces in operating conditions. The statistical parameters of surface roughness Rsk (skewness) and Rku (kurtosis) are more suitable to describe it. In this article the machinability of hypereutectic aluminium alloy (with silicon) parts was examined with the help of design of experiments (DOE). The examinations were carried out with different edge geometry diamond tools. The general and statistical values of machined surface roughness were analysed in detail. Conclusions were drawn on the effect of the...

Aluminium alloys are increasingly used by the automotive and aerospace industries because of thei... more Aluminium alloys are increasingly used by the automotive and aerospace industries because of their numerous advantageous mechanical and chemical properties. Surface roughness is an essential characteristic of a machined surface. The most widespread aluminium alloy used in cutting is the die-cast type, alloyed with silicon. Industries prefer using two types of such alloys, the so-called eutectic and hypereutectic alloys. In this article the machinability of two die-cast aluminium alloys are examined with different edge-geometry tools (conventional - ISO, nonconventional - Wiper) and edge materials. The cutting experiments were carried out with design of experiment – DOE (the so-called central composite design – CCD). In the course of the examination three factors were altered (cutting speed – vc, m/min; feed – f, mm; depth of cut – a, mm), and the main surface roughness parameters used in the industries were taken as output parameters. The parameters of the manufactured surface rough...

Materials Science Forum, 2015

The aluminium alloys are used by the automotive, aerospace industries increasingly because of the... more The aluminium alloys are used by the automotive, aerospace industries increasingly because of their numerous advantageous mechanical and chemical properties. Surface roughness measurements are essential in characterization of the features of a machined surface. The most widespread aluminium alloy used in cutting is the die-cast type, alloyed with silicon. Industries prefer using two types of such alloys, the so-called eutectic and hypereutectic alloys reinforced with silicon. In this article the cutting capacities of two die-cast aluminium alloys are examined. The cutting experiments were carried out with design of experiment – DOE (the so-called central composite design – CCD). In the course of the examination three factors were altered (cutting speed – vc, m/min; feed – f, mm; depth of cut – a, mm), and the main surface roughness parameters used in the industries were taken as output parameters. The parameters of the manufactured surface roughness and their deviation in case of di...

Procedia CIRP, 2013

The paper presents several 3D layout configurator software tools and a library of manufacturing s... more The paper presents several 3D layout configurator software tools and a library of manufacturing system components to rapidly build up the 3D models of manufacturing systems; some analysis tools to analyze the created 3D models; and some methods to rapidly create 3D models from point cloud of scanned manufacturing facilities. Within the configurators the user can define the following data as input: production process (e.g. type and order of operations), type of production equipment, type of material handling systems (e.g. robots, conveyors), type and sub-type of layout, and some spatial constraints (e.g. distance between machines, spatial arrangement). The configurators are able to create the 3D model of the manufacturing systems based on the selection of an appropriate layout template. The layout templates are defined by the species identified with a cladistic classification system or by the sub-species where each sub-species inherits the characteristics of its species. Based on the selected layout template and the defined production process the appropriate elements of the manufacturing system can be selected by the user from a predefined component library. Such library includes the 3D models and technical data of workstations, machine tools, material handling equipment, etc. Two analysis tools have been developed to evaluate the created 3D models: a collision elimination tool and a robot programming tool. The paper also presents two solutions to rapidly create 3D models from point cloud of scanned manufacturing facilities; as well as an application to automatically create a simplified quasi-volumetric point cloud model that can be used for collision detection.

Acta Polytechnica Hungarica, 2014

The aluminium alloys are used by the automotive, aerospace industries increasingly because of the... more The aluminium alloys are used by the automotive, aerospace industries increasingly because of their numerous advantageous mechanical and chemical properties. The cutting of such aluminium alloys is performed with almost exclusively diamond tools. The most often used work piece materials are the so-called Al-Si and Al-Mg-Si alloys, of which the most widespread are reinforced aluminium-silicon alloys. In the practice of technology planning, the average value of surface roughness and surface height of machined work pieces are as important criteria as geometrical sizes (e.g.: length, diameter tolerance). The authors in this article examine the cutting performance of diamond tools having different edge materials with the help of design of experiment. The correlation between the examined surface roughness and the cutting performance was evaluated; additionally the optimal cutting parameters were determined.

Mathematical and Computer Modelling, 2003

Periodica Polytechnica Ser. Mech. Eng, 2006

This paper is focusing on the fact that technological reconstruction is more important than the o... more This paper is focusing on the fact that technological reconstruction is more important than the obligate geometrical reconstruction. We refer in our study to cases of reconstruction of simple mechanical parts with mainly analytical surfaces. This is because technological reconstruction can provide us with the most important information for/about CAPP (Computer-Aided Process Planning). This information is very helpful in the tasks of a designer in operation planning and also in an operation pass planning level.

The most important aim in tool path generation methods is to increase the machining efficiency by... more The most important aim in tool path generation methods is to increase the machining efficiency by minimizing the total length of tool paths while the error is kept under a prescribed tolerance. This can be achieved by determining the moving direction of the cutting tool such that the machined stripe is the widest. From a technical point of view it is recommended that the angle between the tool axis and the surface normal does not change too much along the tool path in order to ensure even abrasion of the tool. In this paper a mathematical method for tool path generation in 3-axis milling is presented, which considers these requirements by combining the features of isophotic curves and principal curvatures. It calculates the proposed moving direction of the tool at each point of the surface. The proposed direction depends on the measurement of the tool and on the curvature values of the surface. For triangulated surfaces a new local offset computation method is presented, which is suitable also for detecting tool collision with the target surface and self intersection in the offset mesh.

The International Journal of Advanced Manufacturing Technology, 2019

It is a well-established fact that when equidistant tool paths are used for 2.5D milling operatio... more It is a well-established fact that when equidistant tool paths are used for 2.5D milling operations tool load varies based on the functions of path curvature. This phenomenon makes the optimal selection of cutting parameters more difficult, and the local load peaks are also detrimental to machining stability and tool life. Numerous publications address possible solutions to eliminate the problems caused by varied cutting parameters. The best solution for this is to keep the cutter engagement at a constant value. Nowadays, several methods are available to generate tool paths which are able to maintain constant cutter engagement, but the widespread use of such solutions is significantly hindered, because in this scenario complex calculations are required. This article offers a solution to this problem by presenting a new non-equidistant offsetting method for ensuring a constant cutter engagement angle. The algorithm developed for this purpose is based on simple geometrical equations and allows for its widespread use just like pixel-based methods. Concerning this new solution, computation needs and uniform tool load are verified by simulation and through experiments. The experiments have shown favourable results. Keywords Tool path generation. Cutter engagement. High-speed milling. Cutting force. Non-equidistant offsetting Nomenclature a e Effective radial immersion [mm] a p Axial depth of cut [mm] c(t) Parametric representation of workpiece contour [{mm, mm}] f z Feed per tooth [mm] h ex Maximum chip thickness [mm] i, j Step index [−] n Spindle speed [1/min] p(t) Parametric representation of tool path [{mm, mm}] r tool Tool radius [mm] s Stepover [mm] t Free parameter of curve equations [−] v Feed vector [{mm, mm}] v c Cutting speed [m/min] v f Feed rate [mm/min] w Trochoidal step [mm] z Number of teeth [−] C Entry point of the cutting edge [{mm, mm}] D tool Tool diameter [mm] MRR Material removal rate [mm 3 /min] P Tool path point [{mm, mm}] Q Exit point of cutting edge [{mm, mm}] V(x, y) Vector field [{mm, mm}, {mm, mm}] a, β Angle parameters [ ∘ ] Δs Stepsize[−] θ Cutter engagement angle [ ∘ ]

Contour parallel milling strategy is still widely used in 2.5D roughing operations. However, in t... more Contour parallel milling strategy is still widely used in 2.5D roughing operations. However, in the case of equidistant tool paths, the tool load strongly depends on the contour’s shape. The paper presents how the cutter engagement can be determined for different contour milling conditions to describe the interaction between the workpiece and the milling tool. Kivonat A 2.5D-s nagyolasi műveleteknel napjainkban is elterjedten hasznaljak a konturparhuzamos marasi strategiat. Az egyenkozű szerszampalyak eseten azonban a szerszam terhelese erősen fugg a kontur alakjatol. A cikkben bemutatjuk, hogy kulonboző konturmarasi viszonyok eseten hogyan irhato le a munkadarab es a szerszam kapcsolodasi viszonyait jellemző kontaktszog erteke.

In computer-aided manufacturing systems a number of methods have been published for milling path ... more In computer-aided manufacturing systems a number of methods have been published for milling path generation considering different geometric requirements and conditions determined by specific environments. In this paper we propose a method for the computation of the moving direction of the cutting tool in 3-axis milling considering the local features of the surface. Our method combines two geometric approaches. Computations are presented on analytical surfaces and on triangle meshes.

Manufacturing Technology, 2015

The industrial use of aluminium alloys has significantly increased in the last decades. Most mach... more The industrial use of aluminium alloys has significantly increased in the last decades. Most machined parts are produced by cutting. Therefore, research in this field is quite important nowadays. Surface roughness is an extremely important quality parameter of a product, such as geometrical sizes and their tolerance. The authors in this article analysed the machinability of die-cast aluminium alloys with silicon often used in the industry. The turning experiments were made with different diamond tools edge geometry. The surface roughness obtained during turning was analysed in detail. Phenomenological models were created with which the surface roughness producing ability of the examined tools can be estimated in technological design.

Fiatal Műszakiak Tudományos Ülésszaka, 2014

The knowledge of the properties of the process of cutting aluminium is getting more and more impo... more The knowledge of the properties of the process of cutting aluminium is getting more and more important nowadays, particularly because of the large number of fields where aluminium alloys can be used, such as in automotive, war and aerospace industries. One of the most widespread index numbers used for measuring surface quality are Ra and Rz values. In this article, the authors examined the cutting capacities of aluminium parts (reinforced with silicon) with the help of design of experiment (DOE). The investigations were carried out with different edge-geometry diamond tools and conclusions were drawn about cutting abilities of the diamond tools used.

Fiatal Műszakiak Tudományos Ülésszaka, 2012

Recently industrial applications of hypereutectic cast aluminium parts has greatly increased. Thi... more Recently industrial applications of hypereutectic cast aluminium parts has greatly increased. This is partly related to their advantegous properties however they are difficult to machine. The paper deals with the environmentalfriendly fine turning of hypereutectic cast aluminium cylinders. In the experiments several PCD tools were used. The surfaces roughness capacity of individual tools, the topological map of the machining and the expected tribological behaviour of turned parts will also be presented. The deteriorating factors of chip formation is examined in relation to the conditions of their formation, their effects and the ways of their avoidence.

Fiatal Műszakiak Tudományos Ülésszaka, 2013

The machining of aluminium parts has been made more important in recent years and decades. The al... more The machining of aluminium parts has been made more important in recent years and decades. The aluminium alloys are used by the automotive, aero and war industrys increasingly because of their numerous good advantageous mechanical and chemical properties. The most often used cut types are the so-called AlMgSi alloys, of which the most widespread are the reinforced silicon alloys. The surface roughness capacity of a diamond tool was examined by design of experiment. Reduced empirical equation was chosen between the cutting paramters and the measured roughness. The optimal area of cutting parameters was defined.

International Journal of Machining and Machinability of Materials, 2017

In cutting research, the determination of the spatial force system of cutting processes is extrem... more In cutting research, the determination of the spatial force system of cutting processes is extremely important. Therefore, the forces generated need to be measured with high precision. In this paper, the development of a special three-component dynamometer system is presented for the measurement of small forces (0…100 N) in three directions during fine cutting, with a precision of 0.1 N. The designed dynamometer employs a piezo-electric cell and can easily be mounted on the tool post with only small modifications to the tool holder. The setup was calibrated for sensitivity, static load and range. By using error functions, the relative error in the measurement of force is kept below 1.5%.

ANZIAM Journal, 2014

Machining of aluminium parts has become particularly important in recent years. Surface roughness... more Machining of aluminium parts has become particularly important in recent years. Surface roughness measurements are essential in the characterization of the surface integrity of a machined surface. To examine the effect of cutting parameters on surface roughness thoroughly, a huge number of experiments are needed, depending on the number of parameters. By utilizing the method of design of experiments, the number of experiments is reduced, as determined by the effects of the parameters. If linear effects of cutting parameters are considered, then fractional factorial design is sufficient, but to take into consideration the interactions between the factors and the quadratic terms, the response surface method has to be utilized.

Procedia CIRP, 2016

In current manufacturing the burr-free edges of the workpieces are required after machining. Subs... more In current manufacturing the burr-free edges of the workpieces are required after machining. Subsequently removing the burrs from the edges of the workpieces increases the cost and time of production. This is the reason why manufacturers try to avoid and reduce the burr. In face milling a possible solution to reduce the burr is the controlling of the exit angle. The exact value of the exit angle can be determined only numerically, however, if the path of the tool edge is approximated with a circle, then the approximation error can be calculated exactly. The chip thickness changes together with the exit angle when using constant feed rate, so the effect of chip thickness has to be considered as well. The exact value of chip thickness can also be determined only numerically, but there are many known approximations that can be applied in practice for the cases when small feed rates are used. An optimal range of exit angle can be estimated with an experiment that is presented in the paper. For circle and line contour elements the path of the tool centre can be determined exactly, which meet the criteria of a given exit angle. The two paths of tool centre belonging to two different exit angles form a closed area. If the tool centre during machining moves inside of this area, then the exit angle remains in the specified range. Depending on the complexity of the workpiece the path of tool centre cannot be always determined for a given exit angle criteria. The paper presents several paths of tool centre belonging to various exit angles for a special workpiece geometry that was used for the experiments. The results of the experiments are presented, which illustrate the efficiency of the method.

UPB Scientific Bulletin, Series D: Mechanical Engineering

Precise knowledge of the machinability of aluminium is more and more important nowadays because a... more Precise knowledge of the machinability of aluminium is more and more important nowadays because aluminium alloys are used by many industries (e.g. the automotive, aerospace and defence industries) and therefore their importance is growing. Two of the most common indices of surface quality are Ra (average surface roughness) and Rz (surface height). However, these surface roughness parameters generally used in the industry do not properly characterise the expected behaviour of machined surfaces in operating conditions. The statistical parameters of surface roughness Rsk (skewness) and Rku (kurtosis) are more suitable to describe it. In this article the machinability of hypereutectic aluminium alloy (with silicon) parts was examined with the help of design of experiments (DOE). The examinations were carried out with different edge geometry diamond tools. The general and statistical values of machined surface roughness were analysed in detail. Conclusions were drawn on the effect of the...

Aluminium alloys are increasingly used by the automotive and aerospace industries because of thei... more Aluminium alloys are increasingly used by the automotive and aerospace industries because of their numerous advantageous mechanical and chemical properties. Surface roughness is an essential characteristic of a machined surface. The most widespread aluminium alloy used in cutting is the die-cast type, alloyed with silicon. Industries prefer using two types of such alloys, the so-called eutectic and hypereutectic alloys. In this article the machinability of two die-cast aluminium alloys are examined with different edge-geometry tools (conventional - ISO, nonconventional - Wiper) and edge materials. The cutting experiments were carried out with design of experiment – DOE (the so-called central composite design – CCD). In the course of the examination three factors were altered (cutting speed – vc, m/min; feed – f, mm; depth of cut – a, mm), and the main surface roughness parameters used in the industries were taken as output parameters. The parameters of the manufactured surface rough...

Materials Science Forum, 2015

The aluminium alloys are used by the automotive, aerospace industries increasingly because of the... more The aluminium alloys are used by the automotive, aerospace industries increasingly because of their numerous advantageous mechanical and chemical properties. Surface roughness measurements are essential in characterization of the features of a machined surface. The most widespread aluminium alloy used in cutting is the die-cast type, alloyed with silicon. Industries prefer using two types of such alloys, the so-called eutectic and hypereutectic alloys reinforced with silicon. In this article the cutting capacities of two die-cast aluminium alloys are examined. The cutting experiments were carried out with design of experiment – DOE (the so-called central composite design – CCD). In the course of the examination three factors were altered (cutting speed – vc, m/min; feed – f, mm; depth of cut – a, mm), and the main surface roughness parameters used in the industries were taken as output parameters. The parameters of the manufactured surface roughness and their deviation in case of di...

Procedia CIRP, 2013

The paper presents several 3D layout configurator software tools and a library of manufacturing s... more The paper presents several 3D layout configurator software tools and a library of manufacturing system components to rapidly build up the 3D models of manufacturing systems; some analysis tools to analyze the created 3D models; and some methods to rapidly create 3D models from point cloud of scanned manufacturing facilities. Within the configurators the user can define the following data as input: production process (e.g. type and order of operations), type of production equipment, type of material handling systems (e.g. robots, conveyors), type and sub-type of layout, and some spatial constraints (e.g. distance between machines, spatial arrangement). The configurators are able to create the 3D model of the manufacturing systems based on the selection of an appropriate layout template. The layout templates are defined by the species identified with a cladistic classification system or by the sub-species where each sub-species inherits the characteristics of its species. Based on the selected layout template and the defined production process the appropriate elements of the manufacturing system can be selected by the user from a predefined component library. Such library includes the 3D models and technical data of workstations, machine tools, material handling equipment, etc. Two analysis tools have been developed to evaluate the created 3D models: a collision elimination tool and a robot programming tool. The paper also presents two solutions to rapidly create 3D models from point cloud of scanned manufacturing facilities; as well as an application to automatically create a simplified quasi-volumetric point cloud model that can be used for collision detection.

Acta Polytechnica Hungarica, 2014

The aluminium alloys are used by the automotive, aerospace industries increasingly because of the... more The aluminium alloys are used by the automotive, aerospace industries increasingly because of their numerous advantageous mechanical and chemical properties. The cutting of such aluminium alloys is performed with almost exclusively diamond tools. The most often used work piece materials are the so-called Al-Si and Al-Mg-Si alloys, of which the most widespread are reinforced aluminium-silicon alloys. In the practice of technology planning, the average value of surface roughness and surface height of machined work pieces are as important criteria as geometrical sizes (e.g.: length, diameter tolerance). The authors in this article examine the cutting performance of diamond tools having different edge materials with the help of design of experiment. The correlation between the examined surface roughness and the cutting performance was evaluated; additionally the optimal cutting parameters were determined.

Mathematical and Computer Modelling, 2003

Periodica Polytechnica Ser. Mech. Eng, 2006

This paper is focusing on the fact that technological reconstruction is more important than the o... more This paper is focusing on the fact that technological reconstruction is more important than the obligate geometrical reconstruction. We refer in our study to cases of reconstruction of simple mechanical parts with mainly analytical surfaces. This is because technological reconstruction can provide us with the most important information for/about CAPP (Computer-Aided Process Planning). This information is very helpful in the tasks of a designer in operation planning and also in an operation pass planning level.

The most important aim in tool path generation methods is to increase the machining efficiency by... more The most important aim in tool path generation methods is to increase the machining efficiency by minimizing the total length of tool paths while the error is kept under a prescribed tolerance. This can be achieved by determining the moving direction of the cutting tool such that the machined stripe is the widest. From a technical point of view it is recommended that the angle between the tool axis and the surface normal does not change too much along the tool path in order to ensure even abrasion of the tool. In this paper a mathematical method for tool path generation in 3-axis milling is presented, which considers these requirements by combining the features of isophotic curves and principal curvatures. It calculates the proposed moving direction of the tool at each point of the surface. The proposed direction depends on the measurement of the tool and on the curvature values of the surface. For triangulated surfaces a new local offset computation method is presented, which is suitable also for detecting tool collision with the target surface and self intersection in the offset mesh.

The International Journal of Advanced Manufacturing Technology, 2019

It is a well-established fact that when equidistant tool paths are used for 2.5D milling operatio... more It is a well-established fact that when equidistant tool paths are used for 2.5D milling operations tool load varies based on the functions of path curvature. This phenomenon makes the optimal selection of cutting parameters more difficult, and the local load peaks are also detrimental to machining stability and tool life. Numerous publications address possible solutions to eliminate the problems caused by varied cutting parameters. The best solution for this is to keep the cutter engagement at a constant value. Nowadays, several methods are available to generate tool paths which are able to maintain constant cutter engagement, but the widespread use of such solutions is significantly hindered, because in this scenario complex calculations are required. This article offers a solution to this problem by presenting a new non-equidistant offsetting method for ensuring a constant cutter engagement angle. The algorithm developed for this purpose is based on simple geometrical equations and allows for its widespread use just like pixel-based methods. Concerning this new solution, computation needs and uniform tool load are verified by simulation and through experiments. The experiments have shown favourable results. Keywords Tool path generation. Cutter engagement. High-speed milling. Cutting force. Non-equidistant offsetting Nomenclature a e Effective radial immersion [mm] a p Axial depth of cut [mm] c(t) Parametric representation of workpiece contour [{mm, mm}] f z Feed per tooth [mm] h ex Maximum chip thickness [mm] i, j Step index [−] n Spindle speed [1/min] p(t) Parametric representation of tool path [{mm, mm}] r tool Tool radius [mm] s Stepover [mm] t Free parameter of curve equations [−] v Feed vector [{mm, mm}] v c Cutting speed [m/min] v f Feed rate [mm/min] w Trochoidal step [mm] z Number of teeth [−] C Entry point of the cutting edge [{mm, mm}] D tool Tool diameter [mm] MRR Material removal rate [mm 3 /min] P Tool path point [{mm, mm}] Q Exit point of cutting edge [{mm, mm}] V(x, y) Vector field [{mm, mm}, {mm, mm}] a, β Angle parameters [ ∘ ] Δs Stepsize[−] θ Cutter engagement angle [ ∘ ]

Contour parallel milling strategy is still widely used in 2.5D roughing operations. However, in t... more Contour parallel milling strategy is still widely used in 2.5D roughing operations. However, in the case of equidistant tool paths, the tool load strongly depends on the contour’s shape. The paper presents how the cutter engagement can be determined for different contour milling conditions to describe the interaction between the workpiece and the milling tool. Kivonat A 2.5D-s nagyolasi műveleteknel napjainkban is elterjedten hasznaljak a konturparhuzamos marasi strategiat. Az egyenkozű szerszampalyak eseten azonban a szerszam terhelese erősen fugg a kontur alakjatol. A cikkben bemutatjuk, hogy kulonboző konturmarasi viszonyok eseten hogyan irhato le a munkadarab es a szerszam kapcsolodasi viszonyait jellemző kontaktszog erteke.