With the development of rapid prototyping technologies, injection mold inserts with conformal cooling systems can be manufactured from metal powder by direct metal laser sintering (DMLS). The ...conformal cooling channels are placed along the geometry of the injection molded product, thus they can extract more heat, and heat removal is more uniform than in the case of conventional cooling systems. But even the most efficient cooling circuits start to wear out, corrosion and limescale depositions precipitate on the wall of the cooling channel, which impede heat transfer from the mold to the coolant. The effect of the depositions cannot be neglected and the modeling of the impact on heat transfer is difficult. We developed a model to investigate the effect of limescale that formed on the wall of the cooling circuit. The thermal properties of the limescale are required for the simulation, therefore they were measured. We concluded that 2mm thick limescale impedes heat removal so much that the more efficient conformal cooling system can only extract as much heat as the less efficient conventional system.
•Cavity Temperature Profile (CTP) in injection molding is investigated.•A combined Artificial Neural Network (ANN) and State Space Model (SSM) is formulated.•ANNs are used to estimate governing SSM ...parameters on-line.•The model predicts the CTP during the injection cycle based on a number of previous cycles.
The applications of artificial intelligence (AI) have considerably expanded over recent years. A new class of industrial systems is beginning to evolve that incorporates using high volume data and advanced analytics to better optimize product quality while reducing energy consumption. Artificial neural networks (ANN) when combined with advanced modeling and control, begins to form an AI platform that can be further enhanced for factories of the future. This paper provides a demonstration of such initial work that can be further developed for future systems in a generic way. When considering polymer processing such as plastic injection molding, the mold cavity temperature (MCT) profile directly relates to part quality and part reject rates. Therefore, it is desirable to optimize the mold cooling process using real time control of MCT as it directly affect part quality. However, MCT is affected by a number of interacting nonlinear dynamic parameters that are often neglected due to the challenge of quantifying such parameters. Advanced model based control algorithms are often used for providing improved control of complex systems. However, they depend on good model formulations that are analytically insufficient. An online intelligent system identification approach for the mold cooling process is developed and tested. An ANN is designed to adjust online sub-space parameters that govern a mold cooling model. Results demonstrate that this online ANN approach can be used to accurately predict the dynamic behavior of mold cavity surface temperature. This is key to many industrial systems where their states are not directly observable and uncertainties are unknown. The methodology can be readily adapted for different operating conditions as in this case of polymer processing and has good potential for its integration with advanced model based control schemes and cloud computing approaches for the next generation of machines.
In this study, an explosive welding process was developed and tested to improve the cooling efficiency of a die casting mold, which was blocked on one side. After explosive welding, the ...microstructure and mechanical properties of the SKD61–pure Cu cylindrical molds were investigated. The stand-off distance and flyer material (Cu) thickness increased with the wave height (pocket morphology) at the interface of the sample. The shear strength also increased with the flyer material thickness and the stand-off distance. The thermal conductivity and cooling performance were also characterized, and it was revealed that the cooling effect of the SKD61 tool alloy + Cu explosive-welded sample was faster than that of the non-explosive-welded sample (approximately 15.8% of the cooling time decreased upon cooling from 270 °C to 25 °C).
The raw/processed data required to reproduce the current findings cannot be publicly available at this time as the data also forms part of an ongoing study.
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•Explosive welding process was developed and tested to improve the cooling efficiency of a die casting mold(SKD61).•Cooling channel of SKD61 and pure Cu bush were well bonded without intermetallic phases.•The shear strength of the EW samples increased with the stand-off distance between the flying bush and mold cooling channel.•The cooling efficiency of the EW sample was improved (15.8% of the cooling time decreased upon cooling from 270 ℃ to 25 ℃).
The work is devoted to development of a new design of horizontal continuous billet casting machine (HCBCM) for non-ferrous and precious metals. The possibility of calculation and design of horizontal ...casting machine elements by means of computer simulation using the software created is demonstrated. Based on the proposed methods of calculation and design as well as analysis of mathematical modeling results, new designs of HCBCM elements are created that enhance the efficiency of the machine. Appraisal trials of HCBCM structural elements created are performed successfully to measure the effectiveness of this work and introduction into production.
In conventional injection molding, due to the differences in mechanical design for mold core and cavity sides, balanced cooling and symmetrical mold temperature are not easily achieved resulting in ...great influence on part warpage. The new development trends for injection molding process include two component injection molding, in-mold decoration, etc. In these molding processes, one side of mold cavity is subjected to significant unbalanced heat transfer even though the cooling channel and coolant operation conditions are the same for both cavity and core sides. Therefore, to solve the warpage under an unbalanced molding cooling and asymmetrical mold temperature condition becomes an important topic for the new injection molding era. In this study, the innovative Gradual Thickness Variation (GTV) method was utilized on the part thickness design combing different cavity and core temperature settings in order to reduce the warpage of IMD parts and common plastic parts. Part thickness reductions were 20%, 30% and up to 40% of the original part thickness. The results reveal when the part thickness reduction percent increases, the warpage increased, which means we can solve warpage value in the injection or IMD part.
This is the second paper of a series that describes the curing process of styrene-butadiene-rubber packed in a cylindrical mold with inner diameter of 74.6 mm. Present paper mainly describes the ...curing process under the mold cooling stage. Sulfur was used as the curing agent and the sulfur concentration ranged from 1.0 to 5.0 weight percent. The mold temperature was controlled in two stages. The mold was heated at 414 K for 45 min. then switched off, and the mold was cooled by natural convection to the surroundings up to 75 min. Time-dependent radial distributions of the temperature profile and the crosslink density were measured in the cooling stage. It was confirmed that the curing reaction was related strongly to the temperature field. In the cooling stage, rubber temperature decreased in the outer zone whereas overshooted in the inner zone. The degree of cure at the rubber center reached to around 0.8 at time 45–60 min. elapsed after taking the heater off for sulfur concentration of 1 and 3 weight percent.
Cooling system design in the TV panel pressing operation is of great importance because it significantly affects productivity and the quality of the final part. It would thus be very helpful for mold ...designers to be able to use a computer aided design tool in determining locations and dimensions of cooling system and process conditions to achieve rapid, uniform and even cooling. For this, a computer simulation has been developed for three-dimensional mold heat transfer of the TV panel pressing process. In the simulation, mold heat transfer is considered as cyclic-steady, three-dimensional conduction; heat transfer within the glass melt region is treated as transient, one-dimensional conduction; heat exchange between the cooling system surface and coolant is treated as steady, as is heat exchange with the ambient air and mold exterior surface. Numerical implementation includes the application of a hybrid scheme consisting of a three-dimensional, boundary element method for the mold region and a finite-difference method with a variable mesh for the melt region. These two analyses are iteratively coupled so as to match the temperature and heat flux at the mold–melt interface. As compared with the experimental data, the numerical simulation developed here is computationally efficient and sufficiently accurate.
This is the second paper of a series that describes the curing process of styrene-butadiene-rubber packed in a cylindrical mold with inner diameter of 74.6 mm. Present paper mainly describes the ...curing process under the mold cooling stage. Sulfur was used as the curing agent and the sulfur concentration ranged from 1.0 to 5.0 weight percent. The mold temperature was controlled in two stages. The mold was heated at 414 K for 45 min. then switched off, and the mold was cooled by natural convection to the surroundings up to 75 min. Time-dependent radial distributions of the temperature profile and the crosslink density were measured in the cooling stage. It was confirmed that the curing reaction was related strongly to the temperature field. In the cooling stage, rubber temperature decreased in the outer zone whereas overshooted in the inner zone. The degree of cure at the rubber center reached to around 0.8 at time 45-60 min. elapsed after taking the heater off for sulfur concentration of 1 and 3 weight percent.
Cooling system design is of great importance for plastic injection molding because it significantly affects the productivity and quality of the final products. The purpose of mold cooling analysis is ...to determine the temperature profile along the cavity wall to improve the cooling system design. In this study, a fully transient mold cooling analysis formulation is developed using the boundary element method (BEM) based on the time-dependent fundamental solution. Then the cyclic transient cooling analysis is performed using this approach for a T-shape plastic part. Compared with the previous work done using finite element method or dual reciprocity boundary element method, domain discretization or use of points internal to the domain can be avoided.
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