{"title":"Synthesis and Analysis of Quality Control Methods for Intelligent Processing of Polymeric Materials","authors":"D. Kazmer, T. Petrova","doi":"10.1115/imece1997-0633","DOIUrl":"https://doi.org/10.1115/imece1997-0633","url":null,"abstract":"\u0000 Global manufacturers of thermoplastic molded parts increasingly require 100% quality inspection levels that are difficult to achieve. While process complexity makes it difficult to attain the desired part properties during start-up. the stochastic nature of the process causes difficulty in maintaining part quality during production. This paper formally compares several alternative quality control methods that are currently utilized for processing of polymeric materials. To identify the technical issues associated with this goal, the injection molding process is described utilizing a control systems approach. Afterwards, four different methods of quality regulation are synthesized for injection molding: open loop quality control, statistical process control, trained parameter control, and on-line quality regression. For each strategy, the level of quality observability and controllability are determined against the dynamics of the manufacturing system.\u0000 The results indicate that none of the quality regulation strategies have the underlying design architecture to deliver 100% quality assurance across a diverse set of application characteristics (quality requirements, material properties, mold geometries, and machine dynamics). As such, subsequent discussion focuses on defining the system requirements for achieving ‘intelligent’ processing of polymeric materials that are needed by industry.","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":"125015463","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}
{"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}
{"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}
{"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}
{"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}
{"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}
{"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}
{"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}
{"title":"Numerical Simulation of Injection/Compression Molding","authors":"T. J. Wang","doi":"10.1115/imece1997-0621","DOIUrl":"https://doi.org/10.1115/imece1997-0621","url":null,"abstract":"\u0000 Injection/compression molding (ICM) is often referred to as coining, stamping, compressive-fill, or hybrid molding. It can produce parts with more homogeneous properties and less molded-in stresses, and this may not be possible with conventional injection molding. It can also produce extremely thin or large parts which may require larger machine if conventional injection molding were used.\u0000 A CAE software has been developed to simulate the ICM process. Two areas will be emphasized to show the advantage of the ICM process over the conventional injection molding process. One is the opening of the mold halves during the molding process allows resin flow to proceed to the extremities of the cavity more easily and consequently reduces the injection pressure and clamping force. Process window design will be discussed. The other is the packing due to the compression motion requires less pressure gradient, i.e., more effective packing. It results in more uniform and smaller pressure throughout the entire cavity. This is essential to produce parts with low residual stress such as compact disk and lens.","PeriodicalId":220828,"journal":{"name":"CAE and Intelligent Processing of Polymeric Materials","volume":"43 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":"122117443","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}
{"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}