A genetic algorithm to obtain optimum parameters for a halcon vision system
- Authors: Fulton, Dale Meares
- Date: 2017
- Subjects: Genetic algorithms , Artificial intelligence , Automation , User interfaces (Computer systems)
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/29751 , vital:30774
- Description: This report discusses the optimisation of a HALCON vision system using artificial intelligence, specifically a genetic algorithm. Within industrial applications, vision systems are often used for automated part inspection and quality control. A number of vision system parameters are to be selected when setting up a vision system. Since each vision system application differs, there is no specific set of optimal parameters. Parameters are selected during installation using a trial and error method. As a result, there is a need for an automated process for obtaining suitable vision system parameters. Within this report, research was conducted on both vision systems, genetic algorithms and integration of the two. A physical vision system was designed and developed utilising HALCON vision software. A genetic algorithm was then developed and integrated with the vision system. After integration, experimental testing was performed on the genetic algorithm in order to determine the ideal genetic algorithm control parameters which yield ideal genetic algorithm performance. Once the ideal genetic algorithm was obtained, the genetic algorithm was applied to the vision system in order to obtain optimal vision system parameters. Results showed that applying the genetic algorithm to the vision system optimised the vision system performance well.
- Full Text:
- Date Issued: 2017
- Authors: Fulton, Dale Meares
- Date: 2017
- Subjects: Genetic algorithms , Artificial intelligence , Automation , User interfaces (Computer systems)
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/29751 , vital:30774
- Description: This report discusses the optimisation of a HALCON vision system using artificial intelligence, specifically a genetic algorithm. Within industrial applications, vision systems are often used for automated part inspection and quality control. A number of vision system parameters are to be selected when setting up a vision system. Since each vision system application differs, there is no specific set of optimal parameters. Parameters are selected during installation using a trial and error method. As a result, there is a need for an automated process for obtaining suitable vision system parameters. Within this report, research was conducted on both vision systems, genetic algorithms and integration of the two. A physical vision system was designed and developed utilising HALCON vision software. A genetic algorithm was then developed and integrated with the vision system. After integration, experimental testing was performed on the genetic algorithm in order to determine the ideal genetic algorithm control parameters which yield ideal genetic algorithm performance. Once the ideal genetic algorithm was obtained, the genetic algorithm was applied to the vision system in order to obtain optimal vision system parameters. Results showed that applying the genetic algorithm to the vision system optimised the vision system performance well.
- Full Text:
- Date Issued: 2017
Computational analysis and cavity optimisation to achieve directional solidification in a cast aluminium alloy [Al7SiMg] component
- Authors: Nohanyaza, Melikhaya
- Date: 2018
- Subjects: Metal castings , Automobiles -- Materials , Alloys , Light metal alloys
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/22913 , vital:30141
- Description: The study at hand focussed on A356.0 industrial and high production die casting alloy. Since the birth of metal casting, numerous researchers have addressed the multiple phenomena that influence the casting quality and mechanical properties of castable alloys. This study harnessed research findings on A356.0 alloy and the aluminium family as a whole, to improve the casting soundness of the component already in the production process. The local foundry showed interest in understanding solidification and quality of A356.0 alloy fluxed with NaCl+KCl melt cleaning flux plus 4 of TiB2 5:1 master alloy grain refining rods and A356.0 alloy processed with KCl+Ti (presumably KCl+TiB2) grain refining flux plus 4 of TiB2 5:1 master alloy rods. Numerical analysis was used to define the progressive nature and directional solidification of the alloy using MAGMA5. MAGMA5.3 virtual optimisation capabilities were used for development of future component casting methods and procedures to solve macro- and microporosity evident on the casting. To find a direct link between the virtual and foundry environment, a preliminary study was conducted on a simple foundry stage of cone billet casting for both alloys with and without mould/casting interface coating. The findings indicated that A356.0 maintained its shrinkage volume percentage at mould temperatures above 300 °C, but progressively increased at temperatures below. Furthermore, thermal insulation coat (also used on Right Hand Side [RHS] mould of the foundry component) influenced the shrinkage distribution on the casting while localised at the centre on non-coated mould/casting interfaces for both KCl+Ti and NaCl+KCl melt fluxed A356.0 at similar percentage shrinkage for mould temperatures greater or equal to 300 °C. Near thin foundry castings for both flux treatments indicated similar mechanical properties at similar casting stages. The mechanical properties of both conditions seemed to degrade as a function of die casting period. Secondary dendrite arm spacing microstructure parameter for NaCl+KCl and KCl+Ti fluxed alloy averaged 40 μm and 35 μm respectively across all test zones. However, individual SDAS definitions per test zone indicated possible micro segregation on NaCl+KCl fluxed alloy and instantaneous solidification as a result of constitutional supercooling on alloys fluxed with KCl+Ti alloy. The growth rate solidification parameter was symmetrical about the centre of the component, where the centre of the component experienced an exponential drop from the top (away from the filling gate) to the bottom (near the filling gate) of the component. A virtual approach to tooling geometrical design indicated a weak influence on both micro- and macroporosity. However, the introduction of low thermal capacity, high heat transfer at Left Hand Side [LHS] tooling and a new cooling system arrangement indicated a higher influence in achieving sound casting. Knowledge gained in this study will improve local foundry competitiveness and introduce cost effective virtual approach foundry developments. The study will also introduce new methods for industrial research and position Nelson Mandela University as a leader in this field.
- Full Text:
- Date Issued: 2018
- Authors: Nohanyaza, Melikhaya
- Date: 2018
- Subjects: Metal castings , Automobiles -- Materials , Alloys , Light metal alloys
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/22913 , vital:30141
- Description: The study at hand focussed on A356.0 industrial and high production die casting alloy. Since the birth of metal casting, numerous researchers have addressed the multiple phenomena that influence the casting quality and mechanical properties of castable alloys. This study harnessed research findings on A356.0 alloy and the aluminium family as a whole, to improve the casting soundness of the component already in the production process. The local foundry showed interest in understanding solidification and quality of A356.0 alloy fluxed with NaCl+KCl melt cleaning flux plus 4 of TiB2 5:1 master alloy grain refining rods and A356.0 alloy processed with KCl+Ti (presumably KCl+TiB2) grain refining flux plus 4 of TiB2 5:1 master alloy rods. Numerical analysis was used to define the progressive nature and directional solidification of the alloy using MAGMA5. MAGMA5.3 virtual optimisation capabilities were used for development of future component casting methods and procedures to solve macro- and microporosity evident on the casting. To find a direct link between the virtual and foundry environment, a preliminary study was conducted on a simple foundry stage of cone billet casting for both alloys with and without mould/casting interface coating. The findings indicated that A356.0 maintained its shrinkage volume percentage at mould temperatures above 300 °C, but progressively increased at temperatures below. Furthermore, thermal insulation coat (also used on Right Hand Side [RHS] mould of the foundry component) influenced the shrinkage distribution on the casting while localised at the centre on non-coated mould/casting interfaces for both KCl+Ti and NaCl+KCl melt fluxed A356.0 at similar percentage shrinkage for mould temperatures greater or equal to 300 °C. Near thin foundry castings for both flux treatments indicated similar mechanical properties at similar casting stages. The mechanical properties of both conditions seemed to degrade as a function of die casting period. Secondary dendrite arm spacing microstructure parameter for NaCl+KCl and KCl+Ti fluxed alloy averaged 40 μm and 35 μm respectively across all test zones. However, individual SDAS definitions per test zone indicated possible micro segregation on NaCl+KCl fluxed alloy and instantaneous solidification as a result of constitutional supercooling on alloys fluxed with KCl+Ti alloy. The growth rate solidification parameter was symmetrical about the centre of the component, where the centre of the component experienced an exponential drop from the top (away from the filling gate) to the bottom (near the filling gate) of the component. A virtual approach to tooling geometrical design indicated a weak influence on both micro- and macroporosity. However, the introduction of low thermal capacity, high heat transfer at Left Hand Side [LHS] tooling and a new cooling system arrangement indicated a higher influence in achieving sound casting. Knowledge gained in this study will improve local foundry competitiveness and introduce cost effective virtual approach foundry developments. The study will also introduce new methods for industrial research and position Nelson Mandela University as a leader in this field.
- Full Text:
- Date Issued: 2018
Diamond turning of contact lens polymers
- Authors: Liman, Muhammad Mukhtar
- Date: 2017
- Subjects: Diamond turning Contact lenses , Electrostatic lenses Lenses -- Design and construction Neural networks (Computer science)
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/19223 , vital:28789
- Description: Contact lens production requires high accuracy and good surface integrity. Surface roughness is generally used to measure the index quality of a turning process. It has been an important response because it has direct influence toward the part performance and the production cost. Hence, choosing optimal cutting parameters will not only improve the quality measure but also the productivity. In this study, an ONSI-56 (Onsifocon A) contact lens buttons were used to investigate the triboelectric phenomena and the effects of turning parameters on surface finish of the lens materials. ONSI-56 specimens are machined by Precitech Nanoform Ultra-grind 250 precision machine and the roughness values of the diamond turned surfaces are measured by Taylor Hopson PGI Profilometer. Electrostatics values were measured using electrostatic voltmeter. An artificial neural network (ANN) and response surface (RS) model were developed to predict surface roughness and electrostatic discharge (ESD) on the turned ONSI-56. In the development of predictive models, turning parameters of cutting speed, feed rate and depth of cut were considered as model variables. The required data for predictive models were obtained by conducting a series of turning test and measuring the surface roughness and ESD data. Good agreement is observed between the predictive models results and the experimental measurements. The ANN and RSM models for ONSI-56 are compared with each other using mean absolute percentage error (MAPE) for accuracy and computational cost.
- Full Text:
- Date Issued: 2017
- Authors: Liman, Muhammad Mukhtar
- Date: 2017
- Subjects: Diamond turning Contact lenses , Electrostatic lenses Lenses -- Design and construction Neural networks (Computer science)
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/19223 , vital:28789
- Description: Contact lens production requires high accuracy and good surface integrity. Surface roughness is generally used to measure the index quality of a turning process. It has been an important response because it has direct influence toward the part performance and the production cost. Hence, choosing optimal cutting parameters will not only improve the quality measure but also the productivity. In this study, an ONSI-56 (Onsifocon A) contact lens buttons were used to investigate the triboelectric phenomena and the effects of turning parameters on surface finish of the lens materials. ONSI-56 specimens are machined by Precitech Nanoform Ultra-grind 250 precision machine and the roughness values of the diamond turned surfaces are measured by Taylor Hopson PGI Profilometer. Electrostatics values were measured using electrostatic voltmeter. An artificial neural network (ANN) and response surface (RS) model were developed to predict surface roughness and electrostatic discharge (ESD) on the turned ONSI-56. In the development of predictive models, turning parameters of cutting speed, feed rate and depth of cut were considered as model variables. The required data for predictive models were obtained by conducting a series of turning test and measuring the surface roughness and ESD data. Good agreement is observed between the predictive models results and the experimental measurements. The ANN and RSM models for ONSI-56 are compared with each other using mean absolute percentage error (MAPE) for accuracy and computational cost.
- Full Text:
- Date Issued: 2017
Energy management system for the diagnosis and control of an automatic guided vehicle
- Authors: Church, Stuart Michael
- Date: 2016
- Subjects: Automated guided vehicle systems , Mechatronics
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/4798 , vital:20681
- Description: With the increase in electronic equipment implemented in various systems, as well as the increase in calculating power that these devices offer, designers are being empowered to make use of this power in real-time systems to diagnose and protect the systems themselves. This reasoning is too compounded by the focus on efficiency and safety in the design of complex systems, as well as the increasing expense and sensitivity of the electronic components themselves. With this in mind, this dissertation aims at developing a comprehensive measurement, control and reaction system for the electrical diagnosis and ultimately optimisation of complex electrical and electronic systems. This system will serve as a real-time diagnosis tool, which will enable the real-time diagnosis of various components in an electro-mechanical system, which can then be interpreted to determine the working state of the various components. Another sphere of this project will involve the accurate monitoring of the battery status as well as actively balancing the series connected batteries. The focus on the batteries will seek to prolong the life of the batteries, while being able to squeeze as much capacity out of them. The initial design and testing will be based on an AGV system implemented at VWSA, however a main goal throughout the design process will be modularity, i.e. the ease of implementation of this system in other systems. The key technologies used in the development of this system will still comprise of the components used in the original AGV, however new prototype components sourced from Microcare are used for the battery management system, while current sensors directly connected to the PLC’s analog input ports will be used for the active monitoring of currents distributed through the AGV.
- Full Text:
- Date Issued: 2016
- Authors: Church, Stuart Michael
- Date: 2016
- Subjects: Automated guided vehicle systems , Mechatronics
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/4798 , vital:20681
- Description: With the increase in electronic equipment implemented in various systems, as well as the increase in calculating power that these devices offer, designers are being empowered to make use of this power in real-time systems to diagnose and protect the systems themselves. This reasoning is too compounded by the focus on efficiency and safety in the design of complex systems, as well as the increasing expense and sensitivity of the electronic components themselves. With this in mind, this dissertation aims at developing a comprehensive measurement, control and reaction system for the electrical diagnosis and ultimately optimisation of complex electrical and electronic systems. This system will serve as a real-time diagnosis tool, which will enable the real-time diagnosis of various components in an electro-mechanical system, which can then be interpreted to determine the working state of the various components. Another sphere of this project will involve the accurate monitoring of the battery status as well as actively balancing the series connected batteries. The focus on the batteries will seek to prolong the life of the batteries, while being able to squeeze as much capacity out of them. The initial design and testing will be based on an AGV system implemented at VWSA, however a main goal throughout the design process will be modularity, i.e. the ease of implementation of this system in other systems. The key technologies used in the development of this system will still comprise of the components used in the original AGV, however new prototype components sourced from Microcare are used for the battery management system, while current sensors directly connected to the PLC’s analog input ports will be used for the active monitoring of currents distributed through the AGV.
- Full Text:
- Date Issued: 2016
Friction welding of thin walled zircaloy-4 tubes for the nuclear industry
- Authors: Koloi, Nthatisi Dinah
- Date: 2017
- Subjects: Friction welding Zirconium alloys
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/18794 , vital:28724
- Description: This work reports on the process development of solid state welding as an alternative joining process for assembling Zircaloy-4 fuel rod components for the nuclear industry. A typical fuel rod consists of a thin tube that is blocked at both ends by end-caps. The welding of the thin wall tubes onto the end-caps is currently accomplished by employing fusion techniques. Due to limited thin wall Zircaloy-4 tube supplied, preliminary welding was initially performed with thin wall 316L stainless steel tube for the development of a joint geometry and establishment of an experimental welding and testing setup. A suitable joint geometry that would achieve higher static strength equal or above that of the parent material, as well as complete circumferential bonding was investigated through welding a tube on different volume interface geometries of the end-caps. Higher joint efficiency was obtained from a tube-to-tube joint geometry that allowed sufficient frictional heat input at the interface. Consequently, the successful joint geometry was employed to develop a friction welding process for the joining of thin wall Zircaloy-4 tubes. The influential process parameters, axial force, rotational speed and upset distance were varied during the investigation. The completed weld joints were evaluated by visual, metallurgical and mechanical means. Successful welds showed complete circumferential bonding and high joint efficiency that was above the parent plate material as well as parent tube material. The evaluation of the microstructure showed transformation of grain structure on the heat affected zone (HAZ) and friction weld zone when compared to the parent materials. Even though, this work could not resolve inner flash formation, there is enough evidence that friction welding can be used for assembling fuel rod components in the nuclear industry.
- Full Text:
- Date Issued: 2017
- Authors: Koloi, Nthatisi Dinah
- Date: 2017
- Subjects: Friction welding Zirconium alloys
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/18794 , vital:28724
- Description: This work reports on the process development of solid state welding as an alternative joining process for assembling Zircaloy-4 fuel rod components for the nuclear industry. A typical fuel rod consists of a thin tube that is blocked at both ends by end-caps. The welding of the thin wall tubes onto the end-caps is currently accomplished by employing fusion techniques. Due to limited thin wall Zircaloy-4 tube supplied, preliminary welding was initially performed with thin wall 316L stainless steel tube for the development of a joint geometry and establishment of an experimental welding and testing setup. A suitable joint geometry that would achieve higher static strength equal or above that of the parent material, as well as complete circumferential bonding was investigated through welding a tube on different volume interface geometries of the end-caps. Higher joint efficiency was obtained from a tube-to-tube joint geometry that allowed sufficient frictional heat input at the interface. Consequently, the successful joint geometry was employed to develop a friction welding process for the joining of thin wall Zircaloy-4 tubes. The influential process parameters, axial force, rotational speed and upset distance were varied during the investigation. The completed weld joints were evaluated by visual, metallurgical and mechanical means. Successful welds showed complete circumferential bonding and high joint efficiency that was above the parent plate material as well as parent tube material. The evaluation of the microstructure showed transformation of grain structure on the heat affected zone (HAZ) and friction weld zone when compared to the parent materials. Even though, this work could not resolve inner flash formation, there is enough evidence that friction welding can be used for assembling fuel rod components in the nuclear industry.
- Full Text:
- Date Issued: 2017
Hybrid additive manufacturing platform for the production of composite wind turbine blade moulds
- Authors: Momsen, Timothy Benjamin
- Date: 2017
- Subjects: Manufacturing processes -- Automation Production control -- Automation , Production management
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/19091 , vital:28772
- Description: This dissertation discusses the application of additive manufacturing technologies for production of a large-scale rapid prototyping machine, which will be used to produce moulds for prototype composite turbine blades for the emerging renewables energy industry within the Eastern Cape region in South Africa. The conceptualization and design of three complete printer builds resulted in the amalgamation of a final system, following stringent theoretical design, simulation, and feasibility analysis. Following the initial product design cycle stage, construction and performance testing of a large-scale additive manufacturing platform were performed. In-depth statistical analysis of the mechatronic system was undertaken, particularly related to print-head locational accuracy, repeatability, and effects of parameter variation on printer performance. The machine was analysed to assess feasibility for use in the mould-making industry with accuracy and repeatability metrics of 0.121 mm and 0.156 mm rivalling those produced by some of the more accurate fused deposition modellers commercially available. The research data gathered serves to confirm that rapid prototyping is a good alternative manufacturing method for wind turbine blade plug and mould production.
- Full Text:
- Date Issued: 2017
- Authors: Momsen, Timothy Benjamin
- Date: 2017
- Subjects: Manufacturing processes -- Automation Production control -- Automation , Production management
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/19091 , vital:28772
- Description: This dissertation discusses the application of additive manufacturing technologies for production of a large-scale rapid prototyping machine, which will be used to produce moulds for prototype composite turbine blades for the emerging renewables energy industry within the Eastern Cape region in South Africa. The conceptualization and design of three complete printer builds resulted in the amalgamation of a final system, following stringent theoretical design, simulation, and feasibility analysis. Following the initial product design cycle stage, construction and performance testing of a large-scale additive manufacturing platform were performed. In-depth statistical analysis of the mechatronic system was undertaken, particularly related to print-head locational accuracy, repeatability, and effects of parameter variation on printer performance. The machine was analysed to assess feasibility for use in the mould-making industry with accuracy and repeatability metrics of 0.121 mm and 0.156 mm rivalling those produced by some of the more accurate fused deposition modellers commercially available. The research data gathered serves to confirm that rapid prototyping is a good alternative manufacturing method for wind turbine blade plug and mould production.
- Full Text:
- Date Issued: 2017
Intelligence based error detection and classification for 3D measurement systems
- Van Rooyen, Ivän Jan-Richard
- Authors: Van Rooyen, Ivän Jan-Richard
- Date: 2017
- Subjects: Computer integrated manufacturing systems Manufacturing processes -- Automation , Computers, Special purpose Neural networks (Computer science)
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/21241 , vital:29461
- Description: For many years 2D machine vision has been used to perform automated inspection and measuring in the manufacturing environment. A strong drive to automate manufacturing has meant improvements in robotics and sensor technologies. So has machine vision seen a steady movement away from 2D and towards 3D. It is necessary to research and develop software that can use these new 3D sensing equipment in novel and useful ways. One task that is particularly useful, for a variety of situations is object recognition. It was hypothesised that it should be possible to train artificial neural networks to recognise 3D objects. For this purpose a 3D laser scanner was developed. This scanner and its software was developed and tested first in a virtual environment and what was learned there was then used to implemented an actual scanner. This scanner served the purpose of verifying what was done in the virtual environment. Neural networks of different sized were trained to establish whether they are a feasible classifier for the task of object recognition. Testing showed that, with the correct preprocessing, it is possible to perform 3D object recognition on simple geometric shapes by means of artificial neural networks.
- Full Text:
- Date Issued: 2017
- Authors: Van Rooyen, Ivän Jan-Richard
- Date: 2017
- Subjects: Computer integrated manufacturing systems Manufacturing processes -- Automation , Computers, Special purpose Neural networks (Computer science)
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/21241 , vital:29461
- Description: For many years 2D machine vision has been used to perform automated inspection and measuring in the manufacturing environment. A strong drive to automate manufacturing has meant improvements in robotics and sensor technologies. So has machine vision seen a steady movement away from 2D and towards 3D. It is necessary to research and develop software that can use these new 3D sensing equipment in novel and useful ways. One task that is particularly useful, for a variety of situations is object recognition. It was hypothesised that it should be possible to train artificial neural networks to recognise 3D objects. For this purpose a 3D laser scanner was developed. This scanner and its software was developed and tested first in a virtual environment and what was learned there was then used to implemented an actual scanner. This scanner served the purpose of verifying what was done in the virtual environment. Neural networks of different sized were trained to establish whether they are a feasible classifier for the task of object recognition. Testing showed that, with the correct preprocessing, it is possible to perform 3D object recognition on simple geometric shapes by means of artificial neural networks.
- Full Text:
- Date Issued: 2017
Mitigation of single event upsets in a XILINX ARTIX-7 field programmable gate array
- Authors: Omolo, Joshua
- Date: 2018
- Subjects: Field programmable gate arrays -- Design and construction Prototypes, Engineering
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/22310 , vital:29942
- Description: Field programmable gate arrays are increasingly being used in harsh environments like space where high energy particles from radiation affect the integrity of the data. Before deployment of satellites in space, characterisation and consequently mitigation of radiation effects is necessary to avoid failure. By irradiating a digital microelectronic device, using accelerated energetic particles, it is possible to predict the likelihood of an event effect happening. Such irradiation tests can only be done at a particle accelerator facility such as iThemba LABS in Cape Town. It is the one of the few particle accelerators in the southern hemisphere and offers the capacity to perform these event effect characterisation tests. Triple Modular Redundancy (TMR) is a commonly used mitigation technique in microelectronics. Although effective, it has the downside of increased resource area. A DMR-Filter combination mitigation technique was developed at the Nelson Mandela University. It uses fewer resources than TMR and it is envisaged to significantly reduce event upsets in a FPGA. This research project seeks to investigate the effectiveness of the DMR-Filter combination mitigation technique in reducing the likelihood of event upsets occurring in Xilinx’s Artix-7 FPGA when exposed to highly accelerated particles, similar to those in space.
- Full Text:
- Date Issued: 2018
- Authors: Omolo, Joshua
- Date: 2018
- Subjects: Field programmable gate arrays -- Design and construction Prototypes, Engineering
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/22310 , vital:29942
- Description: Field programmable gate arrays are increasingly being used in harsh environments like space where high energy particles from radiation affect the integrity of the data. Before deployment of satellites in space, characterisation and consequently mitigation of radiation effects is necessary to avoid failure. By irradiating a digital microelectronic device, using accelerated energetic particles, it is possible to predict the likelihood of an event effect happening. Such irradiation tests can only be done at a particle accelerator facility such as iThemba LABS in Cape Town. It is the one of the few particle accelerators in the southern hemisphere and offers the capacity to perform these event effect characterisation tests. Triple Modular Redundancy (TMR) is a commonly used mitigation technique in microelectronics. Although effective, it has the downside of increased resource area. A DMR-Filter combination mitigation technique was developed at the Nelson Mandela University. It uses fewer resources than TMR and it is envisaged to significantly reduce event upsets in a FPGA. This research project seeks to investigate the effectiveness of the DMR-Filter combination mitigation technique in reducing the likelihood of event upsets occurring in Xilinx’s Artix-7 FPGA when exposed to highly accelerated particles, similar to those in space.
- Full Text:
- Date Issued: 2018
Modelling the effect of graphitization on the fracture toughness (JIC) of service exposed ASTM A-515 Gr. 65 material by the small punch test method
- Authors: Grewar, Stephen James
- Date: 2017
- Subjects: Graphitization Fracture mechanics
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/18849 , vital:28737
- Description: Small Punch Testing is a recent testing methodology with numerous favourable applications in engineering assessments. The advantages of this small specimen method are utilised to derive fracture toughness measurements on service exposed and graphitized steel designated ASTM A-515 Gr. 65. The EPRI-FAA “innovative method”, involving finite element analysis, is applied to obtain fracture toughness estimates and investigate the effect of localised graphitization on localised fracture toughness. The method is described in a stepwise manner and validated favourably against standard fracture toughness testing methods as well as the work of forerunners in this field. Analysis of twenty tested small punch disk specimens extracted from a service exposed welded pipe coupon showed that toughness decreases logarithmically with increased graphitization volumetric percentages in the small samples. Therefore graphitization is found to have a significant influence on local fracture toughness (JIC) of ASTM A-515 Gr. 65 steel under room temperature conditions. The possibility of documenting the effect of microstructural changes on other static properties such as yield strength and strain hardening exists provided that analysis of each disk specimen is performed prior to punch testing. A relationship between percentage graphitization and material toughness has been proposed for ASTM A-515 Gr. 65 at room temperature.
- Full Text:
- Date Issued: 2017
- Authors: Grewar, Stephen James
- Date: 2017
- Subjects: Graphitization Fracture mechanics
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/18849 , vital:28737
- Description: Small Punch Testing is a recent testing methodology with numerous favourable applications in engineering assessments. The advantages of this small specimen method are utilised to derive fracture toughness measurements on service exposed and graphitized steel designated ASTM A-515 Gr. 65. The EPRI-FAA “innovative method”, involving finite element analysis, is applied to obtain fracture toughness estimates and investigate the effect of localised graphitization on localised fracture toughness. The method is described in a stepwise manner and validated favourably against standard fracture toughness testing methods as well as the work of forerunners in this field. Analysis of twenty tested small punch disk specimens extracted from a service exposed welded pipe coupon showed that toughness decreases logarithmically with increased graphitization volumetric percentages in the small samples. Therefore graphitization is found to have a significant influence on local fracture toughness (JIC) of ASTM A-515 Gr. 65 steel under room temperature conditions. The possibility of documenting the effect of microstructural changes on other static properties such as yield strength and strain hardening exists provided that analysis of each disk specimen is performed prior to punch testing. A relationship between percentage graphitization and material toughness has been proposed for ASTM A-515 Gr. 65 at room temperature.
- Full Text:
- Date Issued: 2017
Modular electric automatic guided vehicle suspension-drive unit
- Macfarlane, Alexander Blair Stuart, Van Niekerk, Theo
- Authors: Macfarlane, Alexander Blair Stuart , Van Niekerk, Theo
- Date: 2016
- Subjects: Autonomous vehicles , Sustainable design
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/8220 , vital:25968
- Description: This report discusses the design, development, elevation and creation of a modular omni-directional suspension-drive train unit for use on 1000 kg automatic guided vehicle. The system included a semi-active suspension oleo strut system that can vary its dampening and ride height. The drive train system is capable of omni-directional motion through the use of separately driven mechanum wheels power by a 48 volt DC system.
- Full Text:
- Date Issued: 2016
- Authors: Macfarlane, Alexander Blair Stuart , Van Niekerk, Theo
- Date: 2016
- Subjects: Autonomous vehicles , Sustainable design
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/8220 , vital:25968
- Description: This report discusses the design, development, elevation and creation of a modular omni-directional suspension-drive train unit for use on 1000 kg automatic guided vehicle. The system included a semi-active suspension oleo strut system that can vary its dampening and ride height. The drive train system is capable of omni-directional motion through the use of separately driven mechanum wheels power by a 48 volt DC system.
- Full Text:
- Date Issued: 2016
Neural network fault diagnosis system for a diesel-electric locomotive's closed loop excitation control system
- Authors: Barnard, Morne
- Date: 2017
- Subjects: Neural networks (Computer science) Diesel locomotives -- Motors -- Control systems
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/15955 , vital:28294
- Description: In closed loop control systems fault isolation is extremely difficult due to the fact that if feedbacks are corrupted or actuators can’t produce a desired output, a system reacts due to an increase in error between the measured variable and the set input variable, which can cause oscillations. The goal of this project is to develop a fault detection and isolation system for the isolation of faults, which cause oscillatory conditions on a GE Diesel-Electric Locomotive’s excitation control system. The proposed system will illustrate the use of artificial neural networks as a replacement to classical analytical models. The artificial neural network model’s design will be based on model-based dedicated observer theory to isolate sensor, as well as component faults, where observer theory will be utilised to effectively select input-output data configurations for detection of sensor and component faults causing oscillations. Owing to the nature of the locomotive’s data acquisition abilities, the model-based observer design will utilise historical data to design an effective model of the system which will be used to perform offline sampled fault detection. This method is proposed as an alternative to trend checking, data mining, etc. Faults are thus detected through the use of an offline model-based dedicated observer residual generator. With the use of a neural network a number of parameters affect the accuracy of the network where the primary source of ensuring an accurate model is training. The project highlights and experiments with these parameters to ensure an accurate model is trained with the use of the gradient descent training algorithm. The parameters which are considered are learning rate, hidden layer neurons, momentum and data preparation. The project will also provide a literature review on residual evaluation techniques used in practice and describe and evaluate the proposed method to perform residual evaluation for this specific application. The proposed method for residual evaluation was based on two principles, namely the moving average, as well as the simple thresholding techniques. The developed FDI system’s performance was measured against known faults and produced 100% accuracy for the detection and isolation of sensor and components causing oscillatory conditions on the locomotive’s excitation system.
- Full Text:
- Date Issued: 2017
- Authors: Barnard, Morne
- Date: 2017
- Subjects: Neural networks (Computer science) Diesel locomotives -- Motors -- Control systems
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/15955 , vital:28294
- Description: In closed loop control systems fault isolation is extremely difficult due to the fact that if feedbacks are corrupted or actuators can’t produce a desired output, a system reacts due to an increase in error between the measured variable and the set input variable, which can cause oscillations. The goal of this project is to develop a fault detection and isolation system for the isolation of faults, which cause oscillatory conditions on a GE Diesel-Electric Locomotive’s excitation control system. The proposed system will illustrate the use of artificial neural networks as a replacement to classical analytical models. The artificial neural network model’s design will be based on model-based dedicated observer theory to isolate sensor, as well as component faults, where observer theory will be utilised to effectively select input-output data configurations for detection of sensor and component faults causing oscillations. Owing to the nature of the locomotive’s data acquisition abilities, the model-based observer design will utilise historical data to design an effective model of the system which will be used to perform offline sampled fault detection. This method is proposed as an alternative to trend checking, data mining, etc. Faults are thus detected through the use of an offline model-based dedicated observer residual generator. With the use of a neural network a number of parameters affect the accuracy of the network where the primary source of ensuring an accurate model is training. The project highlights and experiments with these parameters to ensure an accurate model is trained with the use of the gradient descent training algorithm. The parameters which are considered are learning rate, hidden layer neurons, momentum and data preparation. The project will also provide a literature review on residual evaluation techniques used in practice and describe and evaluate the proposed method to perform residual evaluation for this specific application. The proposed method for residual evaluation was based on two principles, namely the moving average, as well as the simple thresholding techniques. The developed FDI system’s performance was measured against known faults and produced 100% accuracy for the detection and isolation of sensor and components causing oscillatory conditions on the locomotive’s excitation system.
- Full Text:
- Date Issued: 2017
Optimisation of glass scoring operation
- Authors: Bechoo, Durvesh Sookraj
- Date: 2016
- Subjects: Glass -- Mechanical properties , Glass manufacture
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/9283 , vital:26559
- Description: The economic crisis and prior recession made a huge dent in many industries. Companies want a cheaper manufactured product with same quality to satisfy the customer in order be competitive yet profitable. Shatterprufe is a company that produces automotive glass. The company has a vast number of products and experience short production run lengths because of its order intake from customers. These short production run lengths require accurate setup to have a repeatable and stable process. An incorrect setup will produce a high scrap rate on production runs. Glass being very brittle and machining it incorrectly results in flaws, breakages or edge stresses that lead to latter process failures. The scoring operation of glass is key to achieve good edge quality to prevent such defects. The correct tools and machine parameters influence good edge quality during the setup procedure. Due to the process having many variables it is difficult to have a stable process and a repeatable stable process. This research will analyse the tool, parameters of the tool and machine parameters to achieve best edge quality and correlating these parameters that will lead to a repeatable stable process. An experimental analysis was conducted on 2.1mm and 2.5mm thick glass. These thicknesses are used predominantly at Shatterprufe automotive glass manufacturing company. The first sample and last sample was analysed during a production run. An average production run length is 36 pieces of glass. The edge quality was seen under a microscope and the fissure depth was measured. To achieve ideal edge quality, the fissure depth must be 15-20% deep of the glass thickness. A fissure is a crack propagated during the scoring of glass. A carbide wheel is used to score the glass. The carbide wheel parameters were varied being the wheel angle and wheel diameter. A 145 degree-4.1mm wheel, 145degree-5.6mm wheel and a 155 degree- 4.1mm wheel was used. The following relationships where observed being the wheel diameter and fissure depth. An increase in wheel diameter resulted in an increase in fissure depth but decreases the wheel life as the wheel becomes blunt. There was inconsistency on fissure depth with the larger diameter wheel. An increased in wheel angle from 145 degree to 155 degree promoted flaws in the glass. Larger wheel angles work better on glass thicknesses of 4-5mm as currently used in the Shatterprufe Struandale Company. An investigation on pressure variation in the pneumatic system was analysed using a pressure transmitter. The pressure transmitter measured the pressure per second versus the set pressure and recorded this data on a data logger. There was no pressure variation in the pneumatic system that can influence poor glass edge quality. A load cell analysis will investigate the physical applied pressure on the glass versus the set pressure. This analysis was to determine the relationship between set versus actual on the glass. It will indicate any mechanical fault. A mechanical fault could be a loose coupling or linkage that can influence the fissure depth. A direct proportional relationship was achieved between the set pressure versus the load cell readings. This indicates no mechanical fault on the system.
- Full Text:
- Date Issued: 2016
- Authors: Bechoo, Durvesh Sookraj
- Date: 2016
- Subjects: Glass -- Mechanical properties , Glass manufacture
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/9283 , vital:26559
- Description: The economic crisis and prior recession made a huge dent in many industries. Companies want a cheaper manufactured product with same quality to satisfy the customer in order be competitive yet profitable. Shatterprufe is a company that produces automotive glass. The company has a vast number of products and experience short production run lengths because of its order intake from customers. These short production run lengths require accurate setup to have a repeatable and stable process. An incorrect setup will produce a high scrap rate on production runs. Glass being very brittle and machining it incorrectly results in flaws, breakages or edge stresses that lead to latter process failures. The scoring operation of glass is key to achieve good edge quality to prevent such defects. The correct tools and machine parameters influence good edge quality during the setup procedure. Due to the process having many variables it is difficult to have a stable process and a repeatable stable process. This research will analyse the tool, parameters of the tool and machine parameters to achieve best edge quality and correlating these parameters that will lead to a repeatable stable process. An experimental analysis was conducted on 2.1mm and 2.5mm thick glass. These thicknesses are used predominantly at Shatterprufe automotive glass manufacturing company. The first sample and last sample was analysed during a production run. An average production run length is 36 pieces of glass. The edge quality was seen under a microscope and the fissure depth was measured. To achieve ideal edge quality, the fissure depth must be 15-20% deep of the glass thickness. A fissure is a crack propagated during the scoring of glass. A carbide wheel is used to score the glass. The carbide wheel parameters were varied being the wheel angle and wheel diameter. A 145 degree-4.1mm wheel, 145degree-5.6mm wheel and a 155 degree- 4.1mm wheel was used. The following relationships where observed being the wheel diameter and fissure depth. An increase in wheel diameter resulted in an increase in fissure depth but decreases the wheel life as the wheel becomes blunt. There was inconsistency on fissure depth with the larger diameter wheel. An increased in wheel angle from 145 degree to 155 degree promoted flaws in the glass. Larger wheel angles work better on glass thicknesses of 4-5mm as currently used in the Shatterprufe Struandale Company. An investigation on pressure variation in the pneumatic system was analysed using a pressure transmitter. The pressure transmitter measured the pressure per second versus the set pressure and recorded this data on a data logger. There was no pressure variation in the pneumatic system that can influence poor glass edge quality. A load cell analysis will investigate the physical applied pressure on the glass versus the set pressure. This analysis was to determine the relationship between set versus actual on the glass. It will indicate any mechanical fault. A mechanical fault could be a loose coupling or linkage that can influence the fissure depth. A direct proportional relationship was achieved between the set pressure versus the load cell readings. This indicates no mechanical fault on the system.
- Full Text:
- Date Issued: 2016
Research and development of an intelligent AGV-based material handling system for industrial applications
- Authors: Ferreira, Tremaine Pierre
- Date: 2015
- Subjects: Robotics -- Industrial applications Artificial intelligence , Mechatronics -- South Africa
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/21711 , vital:29738
- Description: The use of autonomous robots in industrial applications is growing in popularity and possesses the following advantages: cost effectiveness, job efficiency and safety aspects. Despite the advantages, the major drawback to using autonomous robots is the cost involved to acquire such robots. It is the aim of GMSA to develop a low cost AGV capable of performing material handling in an industrial environment. Collective autonomous robots are often used to perform tasks, that is, more than one working together to achieve a common goal. The intelligent controller, responsible for establishing coordination between the individual robots, plays a key role in managing the tasks of each robot to achieve the common goal. This dissertation addresses the development of an AGV capable of such functionality. Key research areas include: the development of an autonomous coupling system, integration of key safety devices and the development of an intelligent control strategy that can be used to govern the operation of multiple AGVs in an area.
- Full Text:
- Date Issued: 2015
- Authors: Ferreira, Tremaine Pierre
- Date: 2015
- Subjects: Robotics -- Industrial applications Artificial intelligence , Mechatronics -- South Africa
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/21711 , vital:29738
- Description: The use of autonomous robots in industrial applications is growing in popularity and possesses the following advantages: cost effectiveness, job efficiency and safety aspects. Despite the advantages, the major drawback to using autonomous robots is the cost involved to acquire such robots. It is the aim of GMSA to develop a low cost AGV capable of performing material handling in an industrial environment. Collective autonomous robots are often used to perform tasks, that is, more than one working together to achieve a common goal. The intelligent controller, responsible for establishing coordination between the individual robots, plays a key role in managing the tasks of each robot to achieve the common goal. This dissertation addresses the development of an AGV capable of such functionality. Key research areas include: the development of an autonomous coupling system, integration of key safety devices and the development of an intelligent control strategy that can be used to govern the operation of multiple AGVs in an area.
- Full Text:
- Date Issued: 2015
Solar thermal performance of a conical helix receiver tube mounted on a parabolic dish
- Nandjembo, Frans Nelongo Pandeni
- Authors: Nandjembo, Frans Nelongo Pandeni
- Date: 2018
- Subjects: Solar energy , Power resources Energy conversion
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/32860 , vital:32379
- Description: This report presents the investigation of a conical helix receiver tube with a zero shading factor to achieve optimal performance of a small concentrating solar thermal collector. In order to understand the working performance of the conical helix receiver tube, it was compared to that of a flat spiral receiver tube. This was done by measuring temperatures at various points as well as the volume airflow rate. Optical studies were achieved using SolTrace to quantify spillage losses and optical efficiency of the dish used in the study from the parabolic dish using a simulation in SolTrace. Comparative tests were conducted between the conical receiver tube and equivalent flat receiver tube at volume air flow rates between 30 m3.h−1 and 45 m3.h−1. The conical helix receiver tube showed a linear temperature distribution, from the outer surface tube towards the inner surface tube in an ascending order, while the flat spiral receiver tube showed a non-linear temperature distribution, its temperature increased in the middle section and decreased towards the inner surface tube. The research showed that an optimally configured helical receiver tube with linear temperature change along its length outperformed the flat receiver tube.
- Full Text:
- Date Issued: 2018
- Authors: Nandjembo, Frans Nelongo Pandeni
- Date: 2018
- Subjects: Solar energy , Power resources Energy conversion
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/32860 , vital:32379
- Description: This report presents the investigation of a conical helix receiver tube with a zero shading factor to achieve optimal performance of a small concentrating solar thermal collector. In order to understand the working performance of the conical helix receiver tube, it was compared to that of a flat spiral receiver tube. This was done by measuring temperatures at various points as well as the volume airflow rate. Optical studies were achieved using SolTrace to quantify spillage losses and optical efficiency of the dish used in the study from the parabolic dish using a simulation in SolTrace. Comparative tests were conducted between the conical receiver tube and equivalent flat receiver tube at volume air flow rates between 30 m3.h−1 and 45 m3.h−1. The conical helix receiver tube showed a linear temperature distribution, from the outer surface tube towards the inner surface tube in an ascending order, while the flat spiral receiver tube showed a non-linear temperature distribution, its temperature increased in the middle section and decreased towards the inner surface tube. The research showed that an optimally configured helical receiver tube with linear temperature change along its length outperformed the flat receiver tube.
- Full Text:
- Date Issued: 2018
Strain behaviour of an eco-car wheel rim designed through topology and composite layup optimization
- Authors: Badenhorst, Martin Wessel
- Date: 2017
- Subjects: Wheels -- Design and construction Mechanical engineering
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/16066 , vital:28317
- Description: This research aimed to reduce the mass of a purpose built eco-car wheel through the sequential use of structural topology and composites optimization software packages while investigating the changes in mass and strain behaviour resulting from altering component geometry, lamina shape, and stacking sequence. The strain behaviour of a commercially available wheel constructed using pre-tensioned steel spokes was established through the comparison of measured physical and FEA strains resulting from applied pressure, radial, lateral, torsional, and combined loads. Structural topology optimization software was then utilized to produce 48 different wheel geometries corresponding to a combined loading scenario consisting of pressure, radial, and lateral loads. The variables controlled during this process included the objective optimization function, safety factor, target design volume, split-draw constraint, and degrees of cyclic symmetry. The optimum geometry was determined by means of evaluating specific stiffness and potential towards being manufactured as a composite component. Three composite wheel FEA base models, with uni-directional laminae stacked at different fibre orientation intervals, were created according to this geometry and lightened by means of composite free size optimization. Composite sizing and shuffling optimizations were then utilized to further enhance the mass and strain characteristics of the lightest of these three solutions Two composite wheels were manufactured according to the wheel geometry, lamina shapes, and stacking sequences determined by means of structural topology and composites ptimizations. The physical mass and strain behaviour of these wheels were measured and compared to those corresponding to the optimized FEA model, as well as the commercially available wheel. This comparison showed that structural topology and composites optimization software packages can be sequentially utilized to produce an adequately stiff composite wheel of lower mass than a commercially available wheel constructed using pre-tensioned steel spokes.
- Full Text:
- Date Issued: 2017
- Authors: Badenhorst, Martin Wessel
- Date: 2017
- Subjects: Wheels -- Design and construction Mechanical engineering
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/16066 , vital:28317
- Description: This research aimed to reduce the mass of a purpose built eco-car wheel through the sequential use of structural topology and composites optimization software packages while investigating the changes in mass and strain behaviour resulting from altering component geometry, lamina shape, and stacking sequence. The strain behaviour of a commercially available wheel constructed using pre-tensioned steel spokes was established through the comparison of measured physical and FEA strains resulting from applied pressure, radial, lateral, torsional, and combined loads. Structural topology optimization software was then utilized to produce 48 different wheel geometries corresponding to a combined loading scenario consisting of pressure, radial, and lateral loads. The variables controlled during this process included the objective optimization function, safety factor, target design volume, split-draw constraint, and degrees of cyclic symmetry. The optimum geometry was determined by means of evaluating specific stiffness and potential towards being manufactured as a composite component. Three composite wheel FEA base models, with uni-directional laminae stacked at different fibre orientation intervals, were created according to this geometry and lightened by means of composite free size optimization. Composite sizing and shuffling optimizations were then utilized to further enhance the mass and strain characteristics of the lightest of these three solutions Two composite wheels were manufactured according to the wheel geometry, lamina shapes, and stacking sequences determined by means of structural topology and composites ptimizations. The physical mass and strain behaviour of these wheels were measured and compared to those corresponding to the optimized FEA model, as well as the commercially available wheel. This comparison showed that structural topology and composites optimization software packages can be sequentially utilized to produce an adequately stiff composite wheel of lower mass than a commercially available wheel constructed using pre-tensioned steel spokes.
- Full Text:
- Date Issued: 2017
Tool wear monitoring in machining of stainless steel
- Authors: Odedeyi Peter Babatunde
- Date: 2017
- Subjects: Mechanical wear Machine-tools -- Monitoring
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/15900 , vital:28288
- Description: monitoring systems for automated machines must be capable of operating on-line and interpret the working condition of machining process at a given point in time because it is an automated and unmanned system. But this has posed a challenge that lead to this research study. Generally, optimization of machining process can be categorized as minimization of tool wear, minimization of operating cost, maximization of process output and optimization of machine parameter. Tool wear is a complex phenomenon, capable of reducing surface quality, increases power consumption and increased reflection rate of machined parts. Tool wear has a direct effect on the quality of the surface finish for any given work-piece, dimensional precision and ultimately the cost of parts produced. Tool wear usually occur in combination with the principal wear mode which depends on cutting conditions, tool insert geometry, work piece and tool material. Therefore, there is a need to develop a continuous tool monitoring systems that would notify operator the state of tool to avoid tool failure or undesirable circumstances. Tool wear monitoring system for macro-milling has been studied using design and analysis of experiment (DOE) approach. Regression analysis, analysis of variance (ANOVA), Box Behnken and Response Surface Methodology (RSM). These analysis tools were used to model the tool wear. Hence, further investigations were carried out on the data acquired using signal processing and Neural networks frame work to validate the model. The effects of cutting parameters are evaluated and the optimal cutting conditions are determined. The interaction of cutting parameters is established to illustrate the intrinsic relationship between cutting parameters, tool wear and material removal rate. It was observed that when working with stainless steel 316, a maximum tool wear value of 0.29mm was achieved through optimization at low values of feed about 0.06mm/rev, speed of 4050mm/min and depth of cut about 2mm.
- Full Text:
- Date Issued: 2017
- Authors: Odedeyi Peter Babatunde
- Date: 2017
- Subjects: Mechanical wear Machine-tools -- Monitoring
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/15900 , vital:28288
- Description: monitoring systems for automated machines must be capable of operating on-line and interpret the working condition of machining process at a given point in time because it is an automated and unmanned system. But this has posed a challenge that lead to this research study. Generally, optimization of machining process can be categorized as minimization of tool wear, minimization of operating cost, maximization of process output and optimization of machine parameter. Tool wear is a complex phenomenon, capable of reducing surface quality, increases power consumption and increased reflection rate of machined parts. Tool wear has a direct effect on the quality of the surface finish for any given work-piece, dimensional precision and ultimately the cost of parts produced. Tool wear usually occur in combination with the principal wear mode which depends on cutting conditions, tool insert geometry, work piece and tool material. Therefore, there is a need to develop a continuous tool monitoring systems that would notify operator the state of tool to avoid tool failure or undesirable circumstances. Tool wear monitoring system for macro-milling has been studied using design and analysis of experiment (DOE) approach. Regression analysis, analysis of variance (ANOVA), Box Behnken and Response Surface Methodology (RSM). These analysis tools were used to model the tool wear. Hence, further investigations were carried out on the data acquired using signal processing and Neural networks frame work to validate the model. The effects of cutting parameters are evaluated and the optimal cutting conditions are determined. The interaction of cutting parameters is established to illustrate the intrinsic relationship between cutting parameters, tool wear and material removal rate. It was observed that when working with stainless steel 316, a maximum tool wear value of 0.29mm was achieved through optimization at low values of feed about 0.06mm/rev, speed of 4050mm/min and depth of cut about 2mm.
- Full Text:
- Date Issued: 2017
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