The formation of orientation field of short fibers suspended in a highly viscous flow through a planar mold cavity is experimentally analyzed. Such flows are common in injection molding of short-fiber-reinforced composite materials. A suspension of corn syrup and nylon fibers is injected at a constant flow rate through a narrow planar inlet gate into an experimental mold cavity. The flow undergoes a sudden expansion near the inlet gate, followed by a three to one contraction downstream. Photographs of thirteen zones of interest in the vicinity of the sudden contraction are taken through transparent mold walls after the flow achieved steady conditions. Computerized image analysis is performed to obtain orientation data for all the fibers within the zones of interest. This data is used to calculate a through the thickness average of the second-order orientation tensor, which is commonly used to quantify orientation field. The experimental results are qualitatively consistent with numerical predictions based on Jeffery’s theory, but quantitative agreement is not satisfactory. Orientation distribution histograms are generated to provide a more detailed representation of the orientation field. The histograms reveal a bimodal distribution, with an alignment peak along the direction of the theoretically calculated preferred orientation, and a second peak perpendicular to the flow direction. The failure of the second-order orientation tensors to quantitatively describe the experimental data seems to be due to these bimodal distributions. Radial orientation histograms at five zones of interest are presented along with the theoretical predictions at these locations.
{"title":"Orientation Formation in Planar Mold Filling: Experimental Results","authors":"K. Olivero, Jufang He, M. Altan","doi":"10.1115/imece1997-0638","DOIUrl":"https://doi.org/10.1115/imece1997-0638","url":null,"abstract":"\u0000 The formation of orientation field of short fibers suspended in a highly viscous flow through a planar mold cavity is experimentally analyzed. Such flows are common in injection molding of short-fiber-reinforced composite materials. A suspension of corn syrup and nylon fibers is injected at a constant flow rate through a narrow planar inlet gate into an experimental mold cavity. The flow undergoes a sudden expansion near the inlet gate, followed by a three to one contraction downstream. Photographs of thirteen zones of interest in the vicinity of the sudden contraction are taken through transparent mold walls after the flow achieved steady conditions. Computerized image analysis is performed to obtain orientation data for all the fibers within the zones of interest. This data is used to calculate a through the thickness average of the second-order orientation tensor, which is commonly used to quantify orientation field. The experimental results are qualitatively consistent with numerical predictions based on Jeffery’s theory, but quantitative agreement is not satisfactory. Orientation distribution histograms are generated to provide a more detailed representation of the orientation field. The histograms reveal a bimodal distribution, with an alignment peak along the direction of the theoretically calculated preferred orientation, and a second peak perpendicular to the flow direction. The failure of the second-order orientation tensors to quantitatively describe the experimental data seems to be due to these bimodal distributions. Radial orientation histograms at five zones of interest are presented along with the theoretical predictions at these locations.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131363434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many types of sensors have been investigated to monitor the process conditions in an injection mold during the molding process. Sensors such as thermocouples, pressure sensors, optical sensors, and ultrasonic sensors have been used to monitor the material, mold, and machine status during molding. Users have always found disadvantages or constrains in application for each type of sensor. Certain sensors can only be applied below a certain temperature. They may be hard to install at a critical location, or have difficulty in making an on-line measurement. A model of the process can predict molding conditions and polymer behavior at any location in the process, but the result is not on-line and the accuracy may be unacceptable. In this work, the signals from a cavity pressure sensor and an ultrasonic sensor are used in conjunction with a finite difference model to predict conditions in an injection mold during molding. The combination improves the model predictions and allows monitoring of variables that are not easily measured. Using this system one sensor is used to provide feed back to improve the model accuracy, while the model acts as a “virtual sensor” predicting the output of a variable that is not as easily measured.
{"title":"Sensor/Model Fusion for Improved Process Understanding and Control in Injection Molding","authors":"Li-Jen Chien, C. L. Thomas, Del R. Lawson","doi":"10.1115/imece1997-0629","DOIUrl":"https://doi.org/10.1115/imece1997-0629","url":null,"abstract":"\u0000 Many types of sensors have been investigated to monitor the process conditions in an injection mold during the molding process. Sensors such as thermocouples, pressure sensors, optical sensors, and ultrasonic sensors have been used to monitor the material, mold, and machine status during molding. Users have always found disadvantages or constrains in application for each type of sensor. Certain sensors can only be applied below a certain temperature. They may be hard to install at a critical location, or have difficulty in making an on-line measurement. A model of the process can predict molding conditions and polymer behavior at any location in the process, but the result is not on-line and the accuracy may be unacceptable. In this work, the signals from a cavity pressure sensor and an ultrasonic sensor are used in conjunction with a finite difference model to predict conditions in an injection mold during molding. The combination improves the model predictions and allows monitoring of variables that are not easily measured. Using this system one sensor is used to provide feed back to improve the model accuracy, while the model acts as a “virtual sensor” predicting the output of a variable that is not as easily measured.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133942469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heat transfer during thermoforming can be conceptually modeled in three distinct stages. In the first stage, the polymer sheet is heated to a temperature above its glass transition temperature in preparation for forming. Heating during this stage is usually accomplished using radiant heaters and causes sagging of the plastic sheet. Once the sheet has attained the necessary forming temperature, the second stage of heat transfer occurs when the polymer sheet is subjected to large stretching during rapid inflation. Heat transfer during this inflation stage is strongly influenced by the large increase in surface area that accompanies stretching of the plastic. Finally, in the third conceptual heat transfer stage, the plastic contacts the metal mold surface and heat is conducted from the hot plastic to the cooler metal surface. Of particular interest in this paper, is the calculation of the cooling that occurs during the rapid inflation phase of polymer processing. Sample calculations are presented for various thermoforming scenarios that illustrate the nature of this cooling mechanism.
{"title":"Numerical Simulation of Heat Transfer During Thermoforming","authors":"C. Wang, H. F. Nied","doi":"10.1115/imece1997-0620","DOIUrl":"https://doi.org/10.1115/imece1997-0620","url":null,"abstract":"\u0000 Heat transfer during thermoforming can be conceptually modeled in three distinct stages. In the first stage, the polymer sheet is heated to a temperature above its glass transition temperature in preparation for forming. Heating during this stage is usually accomplished using radiant heaters and causes sagging of the plastic sheet. Once the sheet has attained the necessary forming temperature, the second stage of heat transfer occurs when the polymer sheet is subjected to large stretching during rapid inflation. Heat transfer during this inflation stage is strongly influenced by the large increase in surface area that accompanies stretching of the plastic. Finally, in the third conceptual heat transfer stage, the plastic contacts the metal mold surface and heat is conducted from the hot plastic to the cooler metal surface. Of particular interest in this paper, is the calculation of the cooling that occurs during the rapid inflation phase of polymer processing. Sample calculations are presented for various thermoforming scenarios that illustrate the nature of this cooling mechanism.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132960604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A 3-D numerical simulation is presented for typical applications in blow moulding involving sequential coextrusion. This technology is applied for the production of automotive boots and opaque containers or bottles with a window stripe. A fluid membrane element is developed and presented for the blow moulding simulation of geometrically complex objects. A Lagrangian formulation is used for the motion governing equations. The numerical tool is applied for predicting the material behaviour in the production of an automotive boot and of a soap bottle with a window stripe. The contact between parison and mould is handled by a robust algorithm. Next to the description of the parison deformation, we concentrate on the prediction of wall thickness, both axial and circumferential extension components and the area stretch ratio as well.
{"title":"3-D Numerical Simulation of Blow Moulding Technology Involving Sequential Coextrusion","authors":"B. Debbaut","doi":"10.1115/imece1997-0643","DOIUrl":"https://doi.org/10.1115/imece1997-0643","url":null,"abstract":"\u0000 A 3-D numerical simulation is presented for typical applications in blow moulding involving sequential coextrusion. This technology is applied for the production of automotive boots and opaque containers or bottles with a window stripe. A fluid membrane element is developed and presented for the blow moulding simulation of geometrically complex objects. A Lagrangian formulation is used for the motion governing equations. The numerical tool is applied for predicting the material behaviour in the production of an automotive boot and of a soap bottle with a window stripe. The contact between parison and mould is handled by a robust algorithm. Next to the description of the parison deformation, we concentrate on the prediction of wall thickness, both axial and circumferential extension components and the area stretch ratio as well.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114750142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to minimize the effects of compositional variation in multiphase, multicomponent polymer mixtures equivalent to those found in commingled waste streams, such as those obtained from reclamation/recycling operations of post-consumer containers, several plastic composites containing varying amounts of glass fiber and different compatibilizers/coupling agents are studied. The glass-fiber reinforced composites, based on characteristic compositions simulating post-consumer “curbside tailings”, have been designed and molded into thin-section parts. Structural, and flow analyses were performed with commercial software on different types of plastic parts. Most of the data used in the simulation were experimentally generated on the compatibilized HDPE based polymer blends containing 20% short glass fibers. Issues concerned with injection molding and product performance are discussed.
{"title":"Prototype Design and Process Optimization Procedure for Products From Glass-Fiber Reinforced Polymer Blends","authors":"K. A. Narh, M. Xanthos","doi":"10.1115/imece1997-0626","DOIUrl":"https://doi.org/10.1115/imece1997-0626","url":null,"abstract":"\u0000 In order to minimize the effects of compositional variation in multiphase, multicomponent polymer mixtures equivalent to those found in commingled waste streams, such as those obtained from reclamation/recycling operations of post-consumer containers, several plastic composites containing varying amounts of glass fiber and different compatibilizers/coupling agents are studied. The glass-fiber reinforced composites, based on characteristic compositions simulating post-consumer “curbside tailings”, have been designed and molded into thin-section parts. Structural, and flow analyses were performed with commercial software on different types of plastic parts. Most of the data used in the simulation were experimentally generated on the compatibilized HDPE based polymer blends containing 20% short glass fibers. Issues concerned with injection molding and product performance are discussed.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130285177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is well known that the injection molding process has an influence on the structural behaviour of the final plastic part. Due to shrinkage- and warpage effects, the final part does not have the same geometry as the mold, and it contains stresses. Nowadays cost and weight restrictions force part designers to use materials up to their mechanical limits. This puts very stringent requirements on the computer aided engineering of the parts and it becomes more and more important to account for the influence of the injection molding process on the part performance. Moldflow is a versatile processing simulation program which, among others, is capable of predicting the warped shape and the molded-in stresses in a part. ABAQUS is a general purpose structural finite element program that is used to predict the behaviour of the part under a specific load. This paper describes an interface between the two programs which transforms the warped shape and the internal stresses as calculated by Moldflow to ABAQUS. A structural analysis can be performed based on the warped shape and taking into account the stresses. The interface has been used to predict the shape of an injection molded thermoplastic fender. For this application, tight gap and flush requirements put strict requirements on the shape of the fender after mounting it on the vehicle. To be able to judge this shape, a special measurement method has been developed by RENAULT. In this method the plastic fender is placed on a measurement jig and fixed in a prescribed order. Afterwards the fender is measured and based on the results of these measurements the shape of the fender can be judged. This procedure is simulated using the interface and taking into account warpage and molded-in stresses. For reasons of comparison, this simulation is also done without taking into account the molded-in stresses. The results of both simulations are compared with actual test data supplied by RENAULT and it can be concluded that accounting for the actual warpage results in a more accurate prediction of the fender shape. The use of the interface can help in finding the optimal fender shape and the best molding conditions at a stage in the design phase where the final fixing system is not yet decided and tools still have to be made. In this way it helps to shorten the design cycle considerably.
{"title":"The Influence of Processing on Structural Behaviour: An Interface Between Moldflow and ABAQUS","authors":"W. Bruijs, Rob Brounné","doi":"10.1115/imece1997-0622","DOIUrl":"https://doi.org/10.1115/imece1997-0622","url":null,"abstract":"\u0000 It is well known that the injection molding process has an influence on the structural behaviour of the final plastic part. Due to shrinkage- and warpage effects, the final part does not have the same geometry as the mold, and it contains stresses. Nowadays cost and weight restrictions force part designers to use materials up to their mechanical limits. This puts very stringent requirements on the computer aided engineering of the parts and it becomes more and more important to account for the influence of the injection molding process on the part performance.\u0000 Moldflow is a versatile processing simulation program which, among others, is capable of predicting the warped shape and the molded-in stresses in a part. ABAQUS is a general purpose structural finite element program that is used to predict the behaviour of the part under a specific load. This paper describes an interface between the two programs which transforms the warped shape and the internal stresses as calculated by Moldflow to ABAQUS. A structural analysis can be performed based on the warped shape and taking into account the stresses.\u0000 The interface has been used to predict the shape of an injection molded thermoplastic fender. For this application, tight gap and flush requirements put strict requirements on the shape of the fender after mounting it on the vehicle. To be able to judge this shape, a special measurement method has been developed by RENAULT. In this method the plastic fender is placed on a measurement jig and fixed in a prescribed order. Afterwards the fender is measured and based on the results of these measurements the shape of the fender can be judged.\u0000 This procedure is simulated using the interface and taking into account warpage and molded-in stresses. For reasons of comparison, this simulation is also done without taking into account the molded-in stresses. The results of both simulations are compared with actual test data supplied by RENAULT and it can be concluded that accounting for the actual warpage results in a more accurate prediction of the fender shape.\u0000 The use of the interface can help in finding the optimal fender shape and the best molding conditions at a stage in the design phase where the final fixing system is not yet decided and tools still have to be made. In this way it helps to shorten the design cycle considerably.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130373806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Integrated simulations of part structural performance, processing characteristics and warpage for the gas-assisted injection molded parts were carried out using a unified CAE model. An analysis algorithm based on DKT/VRT elements superimposed with beam elements representing gas channels of various section geometry was first developed to evaluate part structural performance. During melt/gas filling stage, a mixed control-volume/finite-element/finite-difference method combined with dual-filling-parameter technique was implemented to trace the advancements of melt and gas fronts. For the prediction of secondary gas penetration, flow model of isotropic-shrinkage origin was introduced. Cooling analysis was executed utilizing cycle-averaged boundary element approach considering hollowed core geometry within gas channels. Thermal-induced residual stress was then calculated to predict part warpage. The analysis accuracy from this unified model of 2 1/2-D characteristics show reasonable accuracy when compared with molding experiment and part bending tests. The only difference between process simulation and structure/warpage analyses is that different values of equivalent diameters assigned to beam element representing gas channel should be used, respectively.
{"title":"Integrated Simulations of Structural Performance, Molding Process and Warpage for Gas-Assisted Injection Molded Parts","authors":"S. Chen, N. Cheng, Sheng-yan Hu","doi":"10.1115/imece1997-0617","DOIUrl":"https://doi.org/10.1115/imece1997-0617","url":null,"abstract":"\u0000 Integrated simulations of part structural performance, processing characteristics and warpage for the gas-assisted injection molded parts were carried out using a unified CAE model. An analysis algorithm based on DKT/VRT elements superimposed with beam elements representing gas channels of various section geometry was first developed to evaluate part structural performance. During melt/gas filling stage, a mixed control-volume/finite-element/finite-difference method combined with dual-filling-parameter technique was implemented to trace the advancements of melt and gas fronts. For the prediction of secondary gas penetration, flow model of isotropic-shrinkage origin was introduced. Cooling analysis was executed utilizing cycle-averaged boundary element approach considering hollowed core geometry within gas channels. Thermal-induced residual stress was then calculated to predict part warpage. The analysis accuracy from this unified model of 2 1/2-D characteristics show reasonable accuracy when compared with molding experiment and part bending tests. The only difference between process simulation and structure/warpage analyses is that different values of equivalent diameters assigned to beam element representing gas channel should be used, respectively.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129596891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chaotic mixing of a nonconducting thermoplastic melt and initially coarse clusters of conducting particles has been investigated to assess opportunities for the in-situ formation of extended particle networks. Upon capture by solidification, such extended networks may render the composite electrically conducting. Chaotic advection of small, spherical, non-interacting particles was studied computationally and experimentally ill a cavity formed between two offset cylinders. Numerical tracking of individual particles was performed under conditions where global chaotic mixing prevailed. Formation mechanisms were identified at various stages of mixing. After mixing, networks comprising interconnected particles were identified as electrical pathways. Micrographs of composites produced experimentally by two-dimensional chaotic mixing of thermoplastics with conducting carbon black showed structures resembling those predicted by the simulations and provided further insights into formation mechanisms. The electrical resistivity of the composites is also compared to composites produced by conventional means.
{"title":"Creation of Conducting Networks of Particles in Polymer Melts by Chaotic Mixing","authors":"R. Danescu, D. Zumbrunnen","doi":"10.1115/imece1997-0642","DOIUrl":"https://doi.org/10.1115/imece1997-0642","url":null,"abstract":"\u0000 Chaotic mixing of a nonconducting thermoplastic melt and initially coarse clusters of conducting particles has been investigated to assess opportunities for the in-situ formation of extended particle networks. Upon capture by solidification, such extended networks may render the composite electrically conducting. Chaotic advection of small, spherical, non-interacting particles was studied computationally and experimentally ill a cavity formed between two offset cylinders. Numerical tracking of individual particles was performed under conditions where global chaotic mixing prevailed. Formation mechanisms were identified at various stages of mixing. After mixing, networks comprising interconnected particles were identified as electrical pathways. Micrographs of composites produced experimentally by two-dimensional chaotic mixing of thermoplastics with conducting carbon black showed structures resembling those predicted by the simulations and provided further insights into formation mechanisms. The electrical resistivity of the composites is also compared to composites produced by conventional means.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130815765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Injection molding is known to be the most effective process for producing discrete plastic parts of complex shape to the highest precision at low cost. The concept of Concurrent Engineering (CE) is also recognized to be the way to accomplish the highest performance in a manufacturing enterprise. This paper presents a proposed plan to implement the CE concept to injection molding. IMS (Integrated Molding System) is a new initiative launched at CIMP (Cornell Injection Molding Program) to achieve this goal. The paper reviews the state-of-the-art in all three major functional components in injection molding, i.e. part design, mold design and manufacturing, and process control. Some preliminary results in optimization are presented and discussed in the paper.
{"title":"An Implementation of Concurrent Engineering Concept to Injection Molding","authors":"K. K. Wang","doi":"10.1115/imece1997-0616","DOIUrl":"https://doi.org/10.1115/imece1997-0616","url":null,"abstract":"\u0000 Injection molding is known to be the most effective process for producing discrete plastic parts of complex shape to the highest precision at low cost. The concept of Concurrent Engineering (CE) is also recognized to be the way to accomplish the highest performance in a manufacturing enterprise. This paper presents a proposed plan to implement the CE concept to injection molding. IMS (Integrated Molding System) is a new initiative launched at CIMP (Cornell Injection Molding Program) to achieve this goal. The paper reviews the state-of-the-art in all three major functional components in injection molding, i.e. part design, mold design and manufacturing, and process control. Some preliminary results in optimization are presented and discussed in the paper.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"415 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124817099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fabrication of polymer composite components for automotive applications typically involve the injection of a reactive polymer resin into a preform placed in a closed mold. This process, generally referred to as liquid composite molding, offers the opportunity for part consolidation and fabrication of large, complex shaped parts in a single molding step. A problem often encountered in the molding of composite components is the channeling flow (or race tracking) of resin along the periphery of the preform. This race tracking flow occurs as a result of a small clearance between the preform periphery and the mold. The resistance to flow in the peripheral clearance is much smaller than that in the bulk preform; hence, resin preferentially flows through this region. This paper will present an integrated approach to modeling flow (both in the preform and along the periphery) in the mold cavity. The objective is to model race tracking as part of the overall flow problem. The solution essentially involves the interfacing of the two flow domains along the preform periphery. An integrated approach will not only lead to more accurate model predictions, but will also lead to improved computational efficiency. Example case studies will be presented to illustrate the importance of including race tracking in modeling liquid composite molding operations.
{"title":"Modeling Race Tracking Effects in Liquid Composite Molding","authors":"A. W. Chan, R. J. Morgan","doi":"10.1115/imece1997-0641","DOIUrl":"https://doi.org/10.1115/imece1997-0641","url":null,"abstract":"\u0000 Fabrication of polymer composite components for automotive applications typically involve the injection of a reactive polymer resin into a preform placed in a closed mold. This process, generally referred to as liquid composite molding, offers the opportunity for part consolidation and fabrication of large, complex shaped parts in a single molding step. A problem often encountered in the molding of composite components is the channeling flow (or race tracking) of resin along the periphery of the preform. This race tracking flow occurs as a result of a small clearance between the preform periphery and the mold. The resistance to flow in the peripheral clearance is much smaller than that in the bulk preform; hence, resin preferentially flows through this region.\u0000 This paper will present an integrated approach to modeling flow (both in the preform and along the periphery) in the mold cavity. The objective is to model race tracking as part of the overall flow problem. The solution essentially involves the interfacing of the two flow domains along the preform periphery. An integrated approach will not only lead to more accurate model predictions, but will also lead to improved computational efficiency. Example case studies will be presented to illustrate the importance of including race tracking in modeling liquid composite molding operations.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121044298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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