The Experts below are selected from a list of 39 Experts worldwide ranked by ideXlab platform
Peter Rhys Lewis - One of the best experts on this subject based on the ideXlab platform.
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Premature fracture of a composite nylon radiator
Failure Analysis Case Studies II, 2001Co-Authors: Peter Rhys LewisAbstract:Fracture of a GF nylon composite radiator occurred in a new car, leading to seizure of the engine. The fracture probably started at a Cold Slug or void present on an unusually large weld line in the radiator, itself probably created by poor moulding conditions. Rather than being a design fault, the failure was probably caused by lack of quality control during injection moulding. © 1999 Elsevier Science Ltd. All rights reserved.
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Premature fracture of a composite nylon radiator
Engineering Failure Analysis, 1999Co-Authors: Peter Rhys LewisAbstract:Abstract Fracture of a GF nylon composite radiator occurred in a new car, leading to seizure of the engine. The fracture probably started at a Cold Slug or void present on an unusually large weld line in the radiator, itself probably created by poor moulding conditions. Rather than being a design fault, the failure was probably caused by lack of quality control during injection moulding.
John P. Coulter - One of the best experts on this subject based on the ideXlab platform.
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Development of Advanced Hybrid Polymer Melt Delivery Systems for Efficient High Precision Injection Molding
Journal of Manufacturing Science and Engineering, 2020Co-Authors: Chandresh Thakur, Khalid Alqosaibi, Animesh Kundu, John P. CoulterAbstract:Abstract A novel melt manipulation “RheoDrop” concept for hot runner injection molding is presented. In this concept, a controlled rotational shear is applied to a polymer melt in the hot drop to reduce its viscosity without raising the temperature. This is achieved by providing a transient rotational motion to the valve pin in the hot drop. This strategy is developed to mitigate issues associated with Cold Slug formation during injection molding in hot runner systems. The Cold Slug formation is particularly relevant for injection molding of engineering plastics such as liquid crystal polymers (LCPs) for medical and electronic applications. Analytical and experimental investigations were performed to validate the concept. The efficacy of the concept is assessed analytically utilizing a combination of two software modules, autodesk, moldflow and ansys fluent. The results confirmed that the concept was able to produce enough shear to reduce the dynamic viscosity between injection molding cycles. A prototype RheoDrop system was designed and developed and retrofitted in a four drop hot runner system mold to experimentally validate the concept. Preliminary experiments were performed utilizing acrylonitrile butadiene styrene, and parts were successfully fabricated at temperatures that are too low for traditional molding in a hot runner system.
Thakur Chandresh - One of the best experts on this subject based on the ideXlab platform.
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The Development of Advanced Hybrid Polymer Melt Delivery Systems for Efficient High Precision Injection Molding
Lehigh Preserve, 2016Co-Authors: Thakur ChandreshAbstract:Valve gate systems were originally introduced to control melt flow during the injection molding cycle of hot runner injection molding machines. One of the problems that can arise with such systems is Cold Slug formation during the injection molding cycle. Systems currently being used in industry cannot resolve the issue of the Cold Slug formation while processing semi crystalline polymers using direct gated hot runner system. Moreover, these hot runner systems with valve gating systems exist in the presence of shear imbalance issues as well which lead to poor part quality. There are two main ways to reduce the viscosity of a polymer during an injection molding cycle (1) providing heat and (2) introducing shear. Current hot runner systems consist of heating bands around the runner system which keeps the polymer in the molten stage throughout the injection molding cycle. The solution family focused on during the present study is primarily a shear based technology that introduces rotatory motion of a valve pin which helps to provide shear and reduce the viscosity of the material. The main objective of this research was to solve the Cold Slug formation as well as coloration issues by applying a scientific approach to develop and implement localized shear rate control technology for hot-runner injection molding systems. The subject technology was developed to solve these issues and thus enable high quality precision controlled hot runner injection molding success with an expanded range of materials. This technology was developed to control the part quality throughout the injection molding process. There are several advantages of this technology listed as follows Removal of Cold SlugsHigh quality productsLess cycle timeReduction in shear imbalancesLow material waste Precision moldingReduction in coloration mixture challenges This technology is primarily suited for shear thinning materials. In order to validate the concept, three different categories of materials including a crystalline, semi crystalline and amorphous were studied. Numerical simulations and experimental results of common polymers, such as Ultramid A3EG7 (35% glass filled) (Crystalline), Vectra E130i (Semi-crystalline) and ABS CMold Estimates (Amorphous) were considered. This research focused on reducing the viscosity, within the shear limits of a polymer, by increasing the shear rate. Therefore, a valve pin located in a nozzle of a hot runner system was rotated at different angular velocities. Behavior of the polymer in the lower region of the nozzle was studied at different RPMs and temperature. In depth analysis was performed by developing a scientific idea, re-designing the molding mechanism and running analytical simulations using Autodesk Moldflow, MoldEx3D and Ansys Fluent.The concept was successfully designed and build and also proved using different analytical software. After the proposed changes were implemented in a hot runner system, the technology was successfully generated. Analytical simulations was performed using different software packages such as Autodesk Moldflow, Moldex3D and Ansys Fluent. The analytical simulation revealed that the viscosity was reduced by, on average, 60% at 5000 RPM. The work included in this dissertation advanced science and technology in the field of injection molding process. This dissertation includes the development of a new scientific approach, the design and implementation of a novel new technology and the analytical and to a lesser extent physical validation of the related scientific base
Zhanjun Liu - One of the best experts on this subject based on the ideXlab platform.
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The Research on Injection Mould Design of Bearing Cylinder Plastics
2016Co-Authors: Zhanjun LiuAbstract:Abstract—It is analyzed by the technology plastics materials and molding process of bearing cylinder pieces, which has carried on the mold scheme demonstration and demoulding mechanism, the forming problem of bearing cylinder pieces is solved, and it is designed that the main runner, Cold Slug well, pull rod, the runner and gate of gating system.The ejection force is calculated, and which is design of parting surface. It is given to the assembly diagram of special injection mould. Practice has proved that the bearing cylinder pieces injection mold structure is reasonable, reliable, good machining quality and high production efficiency. Keywords- demoulding mechanism; parting surface; bearing cylinder pieces; injection mould I
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The Research on Injection Mould Design of Bearing Cylinder Plastics
Proceedings of the 2015 International Conference on Mechatronics Electronic Industrial and Control Engineering, 2015Co-Authors: Zhanjun LiuAbstract:It is analyzed by the technology plastics materials and molding process of bearing cylinder pieces, which has carried on the mold scheme demonstration and demoulding mechanism, the forming problem of bearing cylinder pieces is solved, and it is designed that the main runner, Cold Slug well, pull rod, the runner and gate of gating system .The ejection force is calculated, and which is design of parting surface. It is given to the assembly diagram of special injection mould. Practice has proved that the bearing cylinder pieces injection mold structure is reasonable, reliable, good machining quality and high production
Chandresh Thakur - One of the best experts on this subject based on the ideXlab platform.
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Development of Advanced Hybrid Polymer Melt Delivery Systems for Efficient High Precision Injection Molding
Journal of Manufacturing Science and Engineering, 2020Co-Authors: Chandresh Thakur, Khalid Alqosaibi, Animesh Kundu, John P. CoulterAbstract:Abstract A novel melt manipulation “RheoDrop” concept for hot runner injection molding is presented. In this concept, a controlled rotational shear is applied to a polymer melt in the hot drop to reduce its viscosity without raising the temperature. This is achieved by providing a transient rotational motion to the valve pin in the hot drop. This strategy is developed to mitigate issues associated with Cold Slug formation during injection molding in hot runner systems. The Cold Slug formation is particularly relevant for injection molding of engineering plastics such as liquid crystal polymers (LCPs) for medical and electronic applications. Analytical and experimental investigations were performed to validate the concept. The efficacy of the concept is assessed analytically utilizing a combination of two software modules, autodesk, moldflow and ansys fluent. The results confirmed that the concept was able to produce enough shear to reduce the dynamic viscosity between injection molding cycles. A prototype RheoDrop system was designed and developed and retrofitted in a four drop hot runner system mold to experimentally validate the concept. Preliminary experiments were performed utilizing acrylonitrile butadiene styrene, and parts were successfully fabricated at temperatures that are too low for traditional molding in a hot runner system.