Transactions of The Canadian Society for Mechanical Engineering, Sep 1, 2020
Three distinctive regions of tool wear, known as initial wear, steady-state wear, and accelerated... more Three distinctive regions of tool wear, known as initial wear, steady-state wear, and accelerated wear, are well understood. However, the effects of cutting parameters on the initial tool wear mechanism, morphology, and size have received less attention as compared to the other two regions. Knowing that adequate control of initial tool wear may lead to extended tool life, in particular in hard-to-cut metals such as superalloys, this topic has become a source of attention. Amongst superalloys, Inconel 718 is considered as one of the most difficult to cut materials, which has a wide range of industrial applications. This study intends to evaluate the effects of cutting parameters on initial tool wear, as well as tool wear progression, when turning Inconel 718. Therefore, microstructural evaluation of the initial tool wear mode under various cutting conditions, as well as tool wear measurements, were conducted. It was observed that certain elements of the workpieces were migrated to the insert flank face. This is evidence of adhesion at the initial moments of the cutting process. In contrast to many other easy-to-cut materials, the steady-state wear period when turning Inconel 718 is significantly short under a higher level of cutting speed and feed rate.
Abstract This paper presents a new method of machining using variable feed rates which has been d... more Abstract This paper presents a new method of machining using variable feed rates which has been developed by the authors at École Polytechnique de Montreal. A study of the effects of continuously variable feed led to the selection of two discrete feed rates which produce similar results. Machining with two discrete feed rates was tested during the turning of 4140 steel. Results of the experiments indicate a considerable decrease in tool wear; from 30 to 70 percent. This method is simple and can be easily applied in shop floor practice.
International Journal of Refractory Metals & Hard Materials, Nov 1, 2016
Abstract This article presents the findings from a study of the initial tool wear behavior when m... more Abstract This article presents the findings from a study of the initial tool wear behavior when machining the TiMMCs. The results show that the initial wear mechanism of diffusion and adhesion are primarily found for all cutting conditions tested, even though it has been reported that abrasion is the most important mechanism when machining the metal matrix composites. Rapid wear occurs within a very brief period as soon as the cutting action begins and extends to only few seconds at the most. More importantly, we discovered in this study a new wear form, a hard thin layer, at the first transition period. In this case, the effect of chemical stresses under accelerated cutting force and cutting temperature gradient lead to the diffusion wear and built-up edge (BUE) where the tool layer material reacts spontaneously with atmospheric oxygen and oxidizes the titanium and aluminum. These elements then participate in the machining process where the combination of these diffusion wear layer are burnished thermo-chemically under high stress pressure and form a hard smooth layer at the first transition period. Therefore, this layer, herein coined “wear shield”, is considered a protection layer at the beginning of the steady wear period.
Journal of Spinal Disorders & Techniques, Jun 1, 2009
Selection of appropriate curve fusion levels for surgery in adolescent idiopathic scoliosis (AIS)... more Selection of appropriate curve fusion levels for surgery in adolescent idiopathic scoliosis (AIS) is a complex and difficult task and, despite numerous publications, still remains a highly controversial topic. To evaluate a fuzzy-logic-based surgical planning tool by comparing the results suggested by the software with the average outcome recommended by a panel of 5 expert spinal deformity surgeons. It is hypothesized that, given the same information, the fuzzy-logic tool will perform as favorably as the surgeons. Proof-of-concept study evaluating the use of a fuzzy-logic-assisted surgical planning tool in AIS to select the appropriate spinal curve to be instrumented. A cohort of 30 AIS surgical cases with a main thoracic curve was used. Each case included standard measurements recorded from preoperative standing postero-anterior and lateral, supine side bending, and 1-year postoperative standing radiographs. Five experienced spinal deformity surgeons evaluated each case independently and gave their preferred levels of instrumentation and fusion. The cases were then presented to the fuzzy-logic tool to determine whether the high thoracic and/or lumbar curves were to be instrumented. For each case, a percentage value was obtained indicating inclusion/exclusion of the respective curves in the surgical instrumentation procedure. Kappa statistics was used to compare the model output and the average decision of the surgeons. Kappa values of 0.71 and 0.64 were obtained, respectively, for the proximal thoracic and lumbar curves models, thus suggesting a good agreement of the fusion recommendations made by the fuzzy-logic tool and the surgeons. Given the same information, the fuzzy-logic-assisted recommendation of the curve to be instrumented compared favorably with the collective decision of the surgeons. The findings thus suggest that a fuzzy-logic approach is helpful in assisting surgeons with the preoperative selection of curve instrumentation and fusion levels in AIS.
Proceedings of 6th International Fuzzy Systems Conference, Nov 22, 2002
In this paper the latest version of fuzzy decision support system, called FUZZY-FLOU, is describe... more In this paper the latest version of fuzzy decision support system, called FUZZY-FLOU, is described. The system consists of two parts: constructive and destructive ones. Each part includes several methods of approximate reasonings. The system occurs to be useful in various practical problems and can also be employed as an interesting research tool
This paper describes a fuzzy decision support system and its application to the selection of a se... more This paper describes a fuzzy decision support system and its application to the selection of a set of optimal cutting tools to machine a rectangular shaped pocket. The proposed method could be applied to other process planning tasks to help automate this manufacturing process.<<ETX>>
Abstract This paper recalls the idea of a neural controller with application to the control of an... more Abstract This paper recalls the idea of a neural controller with application to the control of an industrial machining process. Structures of such controllers are suggested, and the results of simulations comparing their performance to that of a conventional fuzzy logic controller are shown. The experiments indicate that the performance of the proposed neural controllers is satisfactory.
The authors suggest two structures for a neural fuzzy controller which link the ideas of a fuzzy ... more The authors suggest two structures for a neural fuzzy controller which link the ideas of a fuzzy controller and a neural network. Results of simulations comparing the performance of such a controller to that of a conventional fuzzy logic controller are presented. The experiment indicates that the performance of the neural fuzzy controller is satisfactory. It performs as well as
Abstract An idea and an implementation of a fuzzy decision support system (FDSS) based on the com... more Abstract An idea and an implementation of a fuzzy decision support system (FDSS) based on the compositional rule of inference have been introduced in this paper. Taking into account the fact that metal cutting processes are stochastic, nonlinear and ill-defined, the application of FDSS to the choice and modification of cutting parameters has been described. The obtained results seem to be reasonable and show that the employed methods are appropriate for such kinds of decision problems.
This paper presents a new technique for dealing with tolerance allocation problems, which can be ... more This paper presents a new technique for dealing with tolerance allocation problems, which can be encountered in the design process of mechanical engineering practice. This technique uses a combination of fuzzy logic to evaluate manufacturing difficulties and a simulated annealing algorithm to optimize tolerance allocation over the complete dimensioning chain.
Transactions of The Canadian Society for Mechanical Engineering, Sep 1, 2020
Three distinctive regions of tool wear, known as initial wear, steady-state wear, and accelerated... more Three distinctive regions of tool wear, known as initial wear, steady-state wear, and accelerated wear, are well understood. However, the effects of cutting parameters on the initial tool wear mechanism, morphology, and size have received less attention as compared to the other two regions. Knowing that adequate control of initial tool wear may lead to extended tool life, in particular in hard-to-cut metals such as superalloys, this topic has become a source of attention. Amongst superalloys, Inconel 718 is considered as one of the most difficult to cut materials, which has a wide range of industrial applications. This study intends to evaluate the effects of cutting parameters on initial tool wear, as well as tool wear progression, when turning Inconel 718. Therefore, microstructural evaluation of the initial tool wear mode under various cutting conditions, as well as tool wear measurements, were conducted. It was observed that certain elements of the workpieces were migrated to the insert flank face. This is evidence of adhesion at the initial moments of the cutting process. In contrast to many other easy-to-cut materials, the steady-state wear period when turning Inconel 718 is significantly short under a higher level of cutting speed and feed rate.
Abstract This paper presents a new method of machining using variable feed rates which has been d... more Abstract This paper presents a new method of machining using variable feed rates which has been developed by the authors at École Polytechnique de Montreal. A study of the effects of continuously variable feed led to the selection of two discrete feed rates which produce similar results. Machining with two discrete feed rates was tested during the turning of 4140 steel. Results of the experiments indicate a considerable decrease in tool wear; from 30 to 70 percent. This method is simple and can be easily applied in shop floor practice.
International Journal of Refractory Metals & Hard Materials, Nov 1, 2016
Abstract This article presents the findings from a study of the initial tool wear behavior when m... more Abstract This article presents the findings from a study of the initial tool wear behavior when machining the TiMMCs. The results show that the initial wear mechanism of diffusion and adhesion are primarily found for all cutting conditions tested, even though it has been reported that abrasion is the most important mechanism when machining the metal matrix composites. Rapid wear occurs within a very brief period as soon as the cutting action begins and extends to only few seconds at the most. More importantly, we discovered in this study a new wear form, a hard thin layer, at the first transition period. In this case, the effect of chemical stresses under accelerated cutting force and cutting temperature gradient lead to the diffusion wear and built-up edge (BUE) where the tool layer material reacts spontaneously with atmospheric oxygen and oxidizes the titanium and aluminum. These elements then participate in the machining process where the combination of these diffusion wear layer are burnished thermo-chemically under high stress pressure and form a hard smooth layer at the first transition period. Therefore, this layer, herein coined “wear shield”, is considered a protection layer at the beginning of the steady wear period.
Journal of Spinal Disorders & Techniques, Jun 1, 2009
Selection of appropriate curve fusion levels for surgery in adolescent idiopathic scoliosis (AIS)... more Selection of appropriate curve fusion levels for surgery in adolescent idiopathic scoliosis (AIS) is a complex and difficult task and, despite numerous publications, still remains a highly controversial topic. To evaluate a fuzzy-logic-based surgical planning tool by comparing the results suggested by the software with the average outcome recommended by a panel of 5 expert spinal deformity surgeons. It is hypothesized that, given the same information, the fuzzy-logic tool will perform as favorably as the surgeons. Proof-of-concept study evaluating the use of a fuzzy-logic-assisted surgical planning tool in AIS to select the appropriate spinal curve to be instrumented. A cohort of 30 AIS surgical cases with a main thoracic curve was used. Each case included standard measurements recorded from preoperative standing postero-anterior and lateral, supine side bending, and 1-year postoperative standing radiographs. Five experienced spinal deformity surgeons evaluated each case independently and gave their preferred levels of instrumentation and fusion. The cases were then presented to the fuzzy-logic tool to determine whether the high thoracic and/or lumbar curves were to be instrumented. For each case, a percentage value was obtained indicating inclusion/exclusion of the respective curves in the surgical instrumentation procedure. Kappa statistics was used to compare the model output and the average decision of the surgeons. Kappa values of 0.71 and 0.64 were obtained, respectively, for the proximal thoracic and lumbar curves models, thus suggesting a good agreement of the fusion recommendations made by the fuzzy-logic tool and the surgeons. Given the same information, the fuzzy-logic-assisted recommendation of the curve to be instrumented compared favorably with the collective decision of the surgeons. The findings thus suggest that a fuzzy-logic approach is helpful in assisting surgeons with the preoperative selection of curve instrumentation and fusion levels in AIS.
Proceedings of 6th International Fuzzy Systems Conference, Nov 22, 2002
In this paper the latest version of fuzzy decision support system, called FUZZY-FLOU, is describe... more In this paper the latest version of fuzzy decision support system, called FUZZY-FLOU, is described. The system consists of two parts: constructive and destructive ones. Each part includes several methods of approximate reasonings. The system occurs to be useful in various practical problems and can also be employed as an interesting research tool
This paper describes a fuzzy decision support system and its application to the selection of a se... more This paper describes a fuzzy decision support system and its application to the selection of a set of optimal cutting tools to machine a rectangular shaped pocket. The proposed method could be applied to other process planning tasks to help automate this manufacturing process.<<ETX>>
Abstract This paper recalls the idea of a neural controller with application to the control of an... more Abstract This paper recalls the idea of a neural controller with application to the control of an industrial machining process. Structures of such controllers are suggested, and the results of simulations comparing their performance to that of a conventional fuzzy logic controller are shown. The experiments indicate that the performance of the proposed neural controllers is satisfactory.
The authors suggest two structures for a neural fuzzy controller which link the ideas of a fuzzy ... more The authors suggest two structures for a neural fuzzy controller which link the ideas of a fuzzy controller and a neural network. Results of simulations comparing the performance of such a controller to that of a conventional fuzzy logic controller are presented. The experiment indicates that the performance of the neural fuzzy controller is satisfactory. It performs as well as
Abstract An idea and an implementation of a fuzzy decision support system (FDSS) based on the com... more Abstract An idea and an implementation of a fuzzy decision support system (FDSS) based on the compositional rule of inference have been introduced in this paper. Taking into account the fact that metal cutting processes are stochastic, nonlinear and ill-defined, the application of FDSS to the choice and modification of cutting parameters has been described. The obtained results seem to be reasonable and show that the employed methods are appropriate for such kinds of decision problems.
This paper presents a new technique for dealing with tolerance allocation problems, which can be ... more This paper presents a new technique for dealing with tolerance allocation problems, which can be encountered in the design process of mechanical engineering practice. This technique uses a combination of fuzzy logic to evaluate manufacturing difficulties and a simulated annealing algorithm to optimize tolerance allocation over the complete dimensioning chain.
This paper presents a tool condition monitoring approach using Takagi-Sugeno-Kang (TSK) fuzzy log... more This paper presents a tool condition monitoring approach using Takagi-Sugeno-Kang (TSK) fuzzy logic incorporating a subtractive cluste- ring method. The experimental results show its effectiveness and satisfactory comparisons with several other artificial intelligence methods.
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