Design Of Conformal Cooling Channels Research Articles

Conformal Cooling Channel Design for Improving Temperature Distribution on the Cavity Surface in the Injection Molding Process

Mold heating is an essential process in plastic injection molding. Raising the temperature of the mold before injecting liquefied plastic can ease the mold-filling process. A cooling channel can be used to transport high-temperature fluids for this purpose, such as hot water or oil. This dual purpose is a cost-effective solution for heating the mold because the target temperature is easily achieved using this method. In addition, a conformal cooling channel (CCC) can provide more efficient mold heating than a straight cooling channel. This study used the response surface methodology to determine the optimum CCC shape for heat distribution in a mold, and the simulation results confirmed its optimization. The average temperature of the mold using a CCC was better than that using a straight cooling channel, and the heat zone was uniform across the mold surface.

Design optimization of conformal cooling channels for injection molds: 3D transient heat transfer analysis

This research aims to enhance the design of an injection mold in order to minimize ejection time and increase temperature uniformity by repositioning cooling channels. For 3D transient thermal simulations, the ANSYS finite element method (FEM) program was employed, while the MATLAB program was used for optimization. It was discovered that the method could be used successfully to optimize the design of Conformal Cooling Channels (CCCs) in injection molds. The objective function value of the optimized model represents a near 40% improvement in relation to the initial model. The combined parameterization, simulation, and optimization method has proven beneficial for enhancing the arrangement of channels in an injection machine mold. The methodology is generalizable. As such, it can be employed in any industrial applications involving injection molding machines, for the improvement of the quality of the manufactured part.

Comprehensive performance enhancement of conformal cooling process using thermal-load-based topology optimization

Conformal cooling technology is widely used in the thermal management for injection molding process. However, the overall design of cooling channel layout needs to be optimized due to non-uniform thermal load, limited design freedom and other factors. This paper presents a novel procedure for conformal cooling channel design by using thermal-load-based topology optimization. Unlike previous approaches that focused on optimizing the channel configuration or geometric parameters, the current work applies multiphysics topology optimization on the entire cooling area. The objective is to obtain the optimal channel layout with both low pressure drop and high heat transfer rate. A serious of optimized planar results are converted to three-dimensional channels that conform to the specific injection casting and are applied to injection molding process in a simulation software environment. For a given thin-plate casting, compared with the conventional parallel cooling process, the steady state average temperature and maximum temperature difference are decreased by 0.53 K and 2.20 K, respectively, and the pressure drop of coolant is decreased by 25.40%. For castings where non-uniform thermal loads are considered, the average temperature and pressure drop are decreased up to 1.45 K and 27.55%, respectively. The results for both sheet castings and cylindrical castings have demonstrated the stability, flexibility, and rationality of the proposed procedure. In addition, the conceptual design of cooling channels based on thermal load is expected to be applied to more potential thermal engineering fields.

Optimization of 3D Cooling Channels in Plastic Injection Molds by Taguchi-Integrated Principal Component Analysis (PCA)

Injection molding has become an increasingly widely used method in the production of plastic parts. The injection process can be separated into five steps: mold closure, filling, packing, cooling, and product ejection. Before the melted plastic is loaded into the mold, the mold needs to be raised to a specified temperature, in order to increase the mold's filling capacity and improve the resultant product quality. One of the easy methods used to control a mold's temperature is to provide hot water through a cooling channel in the mold, to raise the temperature. In addition, this channel can be used for cooling the mold with cool fluid. This is simple, effective, and cost efficient, involving uncomplicated products. To improve the heating effectiveness of the hot water, a conformal cooling-channel design is considered in this paper. Through heat-transfer simulation using the CFX module in the Ansys software, an optimal cooling channel was defined according to the simulation result, using the Taguchi method integrated with principal component analysis. The comparison of traditional vs. conformal cooling channels revealed higher temperature rises in the first 100 s in both molds. During heating, conformal cooling produced higher temperatures compared with traditional cooling. Conformal cooling demonstrated better performance, with average temperature peaking at 58.78 °C and a range of 63.4 °C (max) to 54.66 °C (min). Traditional cooling resulted in an average steady-state temperature of 56.63 °C and a range of 61.74 °C (max) to 53.18 °C (min). Finally, the simulation results were verified experimentally.

Influence of Conformal Cooling Channel Parameters on Hot Stamping Tool and Press-Hardening Process

Press hardening is a technology increasingly used in the automotive industries to produce high-strength structural parts in boron steel. The part strengthening is due to a martensitic microstructure, which is obtained during the quenching phase of the process by imposing cooling rates typically higher than 27 K/s. To improve cooling efficiency, conformal cooling channels (CCC) are increasingly adopting thanks to opportunities offered by additive manufacturing (AM) technologies in combination with the development of powders with high thermal conductivity.In this work a methodology for the design of CCC inside hot stamping tools is presented and the press hardening of an automotive B-Pillar in 22MnB5 has been used as case study. The proposed methodology provides for an optimization of the distance between the cooling channels (p) and distance between the tool surface and the cooling channel center (d).

Rapid Development of an Injection Mold with High Cooling Performance Using Molding Simulation and Rapid Tooling Technology.

Rapid tooling technology (RTT) provides an alternative approach to quickly provide wax injection molds for the required products since it can reduce the time to market compared with conventional machining approaches. Removing conformal cooling channels (CCCs) is the key technology for manufacturing injection mold fabricated by rapid tooling technology. In this study, three different kinds of materials were used to fabricate CCCs embedded in the injection mold. This work explores a technology for rapid development of injection mold with high cooling performance. It was found that wax is the most suitable material for making CCCs. An innovative method for fabricating a large intermediary mold with both high load and supporting capacities for manufacturing a large rapid tooling using polyurethane foam was demonstrated. A trend equation for predicting the usage amount of polyurethane foam was proposed. The production cost savings of about 50% can be obtained. An optimum conformal cooling channel design obtained by simulation is proposed. Three injection molds with different cooling channels for injection molding were fabricated by RTT. Reductions in the cooling time by about 89% was obtained. The variation of the results between the experiment and the simulation was investigated and analyzed.

Realistic design of laser powder bed fusion channels

PurposeConformal cooling channels in additively manufactured molds are superior over conventional channels in terms of cooling control, part warpage and lead time. The heat transfer ability of cooling channels is determined by their geometry and surface roughness. Laser powder bed fusion manufactured channels have an inherent process-induced dross formation that may significantly alter the actual shape of nominal channels. Therefore, it is crucial to be able to predict the expected surface roughness and changes in the geometry of metal additively manufactured conformal cooling channels. The purpose of this paper is to present a new methodology for predicting the realistic design of laser powder bed fusion channels.Design/methodology/approachThis study proposes a methodology for making nominal channel design more realistic by the implementation of roughness prediction models. The models are used for altering the nominal shape of a channel to its predicted shape by point cloud analysis and manipulation.FindingsA straight channel is investigated as a simple case study and validated against X-ray computed tomography measurements. The modified channel geometry is reconstructed and meshed, resulting in a predicted, more realistic version of the nominal geometry. The methodology is successfully tested on a torus shape and a simple conformal cooling channel design. Finally, the methodology is validated through a cooling test experiment and comparison with simulations.Practical implicationsAccurate prediction of channel surface roughness and geometry would lead toward more accurate modeling of cooling performance.Originality/valueA robust start to finish method for realistic geometrical prediction of metal additive manufacturing cooling channels has yet to be proposed. The current study seeks to fill the gap.

Characterization of a direct metal printed injection mold with different conformal cooling channels

According to the practical experiences in the injection molding, the knowledge about conformal cooling channel (CCC) is an essential factor that affects productivity and quality of the molded part greatly. In general, the CCC provides a reduction in the cooling time in series production. However, the distance between cooling channel edges of the circular conformal cooling channel (CCCC) and mold cavity edge is not constant. The profiled conformal cooling channel (PCCC) has flat surface of the cooling channel facing the profile of the cavity fully. The distance between cooling channel edges of the PCCC and mold cavity edge is constant. In this study, two maraging steel injection molding tools with two different CCC were designed and fabricated by the direct metal printing technology. The difference between injection mold with PCCC and CCCC on the cooling time of the molded wax pattern, part temperature difference, mold surface temperature difference, and part warpage were numerically investigated using Moldex3D simulation software. It was found that the PCCC seems to be a good candidate in the CCC design and provides a better alternative in the conventional cooling channels. The PCCC reduced the cooling time about 33.33% compared with CCCC under the coolant water temperature of 25 °C. The temperature of 26 °C is the optimal value for the coolant water based on the dimensional accuracy of the wax pattern and energy consumption of the cooling system.

Efficiency of Conformal Cooling Channels Inserts for Extrusion Dies

During aluminum extrusion process, critical temperatures can be reached both in the profile and in the tooling set due to the high pre-heating temperatures and to the work spent in overcoming friction at the workpiece/tool interfaces and in deforming the billet that is converted into heat. By considering that especially the rising of temperature in the profile can represents a critical aspect of the process strongly limiting the maximum achievable extrusion speed, liquid nitrogen die cooling is becoming a consolidated industrial practice in order to increase the process productivity. If cooling channels are traditionally manufactured by subtractive technologies on a third plate (the backer), a more flexible and efficient solution is offered by the selective laser melting (SLM) technology. SLM allows the design of free-form channels with the opportunity to efficiently remove the heat as near as possible to the bearing zones where the highest temperatures are reached. In the present work, the design approach and the manufacturing parameters of an SLM printed H13 die insert for the extrusion of a 10 mm round bar are presented. In addition, the extrusion process is simulated by means of the COMSOL code accounting for the nitrogen cooling effect. Experimental extrusion trials have been furthermore performed with ZM21 magnesium and 6063 aluminum alloys to assess the potentiality of the conformal cooling channel design and to validate the developed numerical model. As main result, a good experimental numerical matching has been achieved with peak errors of 7.5% and 14% in terms of temperature and extrusion load respectively.

Design of Conformal Cooling Channels Using Numerical Methods in a Metal Mold and Calculating Exergy Destruction in Channels

Shorter cycle times, better product quality and less product outage can be possible with faster cooling. But mold cooling channels can only be made in linear directions and limited forms via classical manufacturing methods. Therefore, it limits that performance of mold cooling. Developed in recent years additive manufacturing technologies are capable of building complex geometries and monoblock 3D products. With this technology it is possible to produce metal molds with conformal cooling channels in different forms and capable of qualified cooling. In this study, conformal cooling channels were designed in order to achieve optimum cooling in monoblock permanent mold. In this study, CFD (Computational Fluid Dynamic) analyses are performed to steady stead conditions for designed conformal cooling channels and classical cooling channel mold. Pressure drops, cooling channel outlet temperatures and exergy destructions are calculated depending on the flow velocity rate in channels. The numerical investigations of the cooling process have shown that approximately 5% higher cooling performance can be achieved with conformal cooling channels. However, the pressure drop in the conformal cooling is observed to be higher than classical cooling channel. In addition, exergy destruction in the conformal cooling channel is approximately 12% greater than the classical cooling channel.

Improving the Quality and Productivity of Molded Parts with a New Design of Conformal Cooling Channels for the Injection Molding Process

ABSTRACTIn materials processing, quality and productivity are notably important and must be controlled for each product type produced. In the injection molding process, quality is measured as the extent of warpage of molded parts and productivity is measured in terms of the molding cycle time. This paper presents a new design of milled grooved square shape (MGSS) conformal cooling channels, which provide more uniformity in cooling with a larger effective cooling surface area compared to circular and other types of cooling channels with a similar cross‐section. This study examined the warpage of molded parts, and the cooling time, which affected the molding cycle time. A case study involving a front panel housing was performed, and the performance design of the MGSS conformal cooling channels was compared to that of conventional straight‐drilled cooling channels by simulation using Autodesk Moldflow Insight 2013 and validated experimentally. The result of MGSS conformal cooling channels is in a good agreement with the result of simulation. The MGSS conformal cooling channels reduced the warpage in both x and y directions by 14% to 54% and improved the cooling time by 65% compared to straight‐drilled cooling channels.

Variable Distance Adjustment for Conformal Cooling Channel Design in Rapid Tool

During thermoplastic injection moulding process, the gradual increase of the coolant temperature along the conformal cooling channel (CCC) inside the rapid tool reduces the rate of heat transfer from the polymeric melt to the cooling channel surface at the outlet portion. Injection moulded defects such as irregular warpage of the part between the coolant inlet and outlet cannot be avoided. Rapid tooling (RT) technology offers a speedy and automatic method for rapid tool design and fabrication integrated with complex internal structure such as CCC. This paper presents a novel adjustment method for cooling distance modification between the CCC and its mould cavity (or core) surface along the cooling channel. The proposed method can compensate the gradual increase of the coolant temperature from the coolant inlet to the coolant outlet. More heat can be transferred from the mould surface near the coolant outlet to the proposed variable distance conformal cooling channel (VDCCC). In this study, the cooling channel distance modification relies on two adjustment attributes: (1) the adjustment direction and (2) the adjustment amount, between the mould cavity (or core) surface (terrain) and the cooling channel axis (polyline) after the linearized approximation. A computer-aided melt flow analysis tool of moldflow plastics insight is employed in the case study in order to demonstrate the feasibility of the proposed method. The cooling performance of the proposed VDCCC design can be verified.

Cycle Time Reduction in Injection Molding Process by Selection of Robust Cooling Channel Design

Cycle time of a part in injection molding process is very important as the rate of production and the quality of the parts produced depend on it, whereas the cycle time of a part can be reduced by reducing the cooling time which can only be achieved by the uniform temperature distribution in the molded part which helps in quick dissipation of heat. Conformal cooling channel design is the solution to the problem which basically “conforms” to the shape of cavity in the molds. This paper describes the analytical study of cooling analysis of different types of cooling channel designs. The best cooling channel design is also selected on the basis of minimum time to reach ejection temperature, uniform temperature distribution, and minimum warpage of part. “Creo Elements/Pro 5.0” is used to model the case study, its molds, and the cooling circuit whereas analytical study is done using “Autodesk Moldflow Advisor 2013 (AMFA).”

Conformal cooling channel design and CAE simulation for rapid blow mould

Blow moulding is one of the most important polymer processing technologies to produce hollow-shaped parts at a short time. The cooling stage takes up approximately two thirds of the complete blow moulding cycle. It becomes the major factor to determine the productivity and the quality of the blow-moulded part. The cooling time and the quality part are controlled by an adequate cooling channel design inside the blow mould. Inappropriate cooling channel design will increase the cooling time after part ejection. Recently, the success of integrating conformal cooling channel (CCC) design in the injection moulding process has been proven by different research publications and practices. The merit of the applications of CCC can also be extended to the existing blow moulding process. In this study, an effective design method is proposed for integrating CCC into the blow mould with the aid of computer-aided design and analysis tools. The fabrication of integrating CCC into the blow mould by rapid tooling technology is explored. Computer-aided engineering simulation is employed to verify the cooling performance of the CCC corresponding to the blow mould surface geometry. The analysed results are compared with those using the traditional straight line-drilled cooling channel (SLDCC) used in the blow moulding process. The results indicated that the cooling time and temperature uniformity of the blow-moulded part can be effectively improved. The proposed CCC design has a shorter cooling time and a lower part temperature than the SLDCC one.

Thermal–structural analysis of bi-metallic conformal cooling for injection moulds

In injection moulding process, cooling time greatly affects the total cycle time. As thermal conductivity is one of the main factors for conductive heat transfer in cooling phase of IMP, a cooling channel made by higher thermal conductive material will allow faster extraction of heat from the molten plastic materials, thus resulting in shorter cycle time and higher productivity. The main objective of this paper is to investigate bi-metallic conformal cooling channel design with high thermal conductive copper tube insert for injection moulds. Thermal–structural finite element analysis has been carried out with ANSYS workbench simulation software for a mould with bi-metallic conformal cooling channels and the performance is compared with a mould with conventional straight cooling channels for an industrial plastic part. Experimental verification has been carried out for the two moulds using two different types of plastics, polypropylene (PP) and acrylonitrile butadiene styrene, in a mini injection moulding machine. Simulation and experimental results show that bi-metallic conformal cooling channel design gives better cycle time, which ultimately increases production rate as well as fatigue life of the mould.

Modeling of multi-connected porous passageway for mould cooling

Cooling channel design in the plastic injection moulding process is of paramount importance to the performance of the mould, influencing the quality of the parts being produced and productivity of the process. However, cooling channel design is usually limited to relatively simple configurations as well as conventional machining processes, such as straight-line drilling, and milling, etc. The cooling performance may not meet the expectations of the mould engineers. This paper proposes an alternative design method for a conformal cooling passageway with multi-connected porous characteristics based on the duality principle. The proposed method can provide a more uniform cooling performance between the mould plate and the conformal cooling passageway than the existing conformal cooling channel design. Injection mould defects like warpage or hot spots can be avoided. In this study, a 3D mould plate model was offset negatively and the location of the proposed multi-connected porous cooling passageway was identified. The negatively offset model was decomposed into a finite number of cubical cells via the sub-boundary spatial enumerated cell decomposition. Then a duality relationship between the primal and the dual graphs was developed. This provided the preliminary layout of the multi-connected porous passageway for the coolant flow in multiple directions. The cooling channel axis design of the multi-connected porous passageway, illustrated by the skeleton from the dual graph, was created. Following a Boolean difference operation, the proposed multi-connected porous cooling passageway inside the mould plate was able to be generated and fabricated with the aid of rapid tooling technologies. A real-life case study for the design of a multi-connected porous cooling passageway was implemented and examined. The effects of coolant flow and cooling performances, analyzed by computational fluid dynamics simulation, were validated.

Optimum Cooling Channels Design and Thermal Analysis of an Injection Moulded Plastic Part Mould

Cooling channel design is important in mould designs to achieve shorter cycles, dimensional stability and reduced part stresses. Traditionally, cooling channels have been machined into mould components to avoid interference with the ejection system, coring, cavity and other mould details. Over the years straight drilled cooling channels have given away, in part, to conformal cooling technique often using free form fabrication techniques. This paper presents a study of optimised mould design with conformal cooling channel using finite element analysis. Various configurations of conformal cooling channels have been developed. The part cooling time using the conformal cooling channels and the straight cooling channels in the mould are computed using the Pro/Mechanica Thermal FEA software. Results are presented based on temperature distribution and cooling time using steady state and transient analysis conditions. The results show a reduction in cycle time for the plastic part with conformal cooling channel design.

Analysis of cooling channels performance

The die casting industry is under increasing pressure to improve production rates to enable greater productivity. Employing conformal cooling channels could potentially improve a die performance through the reduction of solidification times. The paper reviews simulated solidification results from a traditional cooling channel design and a conformal cooling channel design. The paper continues by describing the construction of bonded laminate insert with integrated cooling channels. Casting trials were conducted using the inserts to validate the simulated results. Work to date has demonstrated the ability to manufacture laminate inserts quickly, the accuracy of finite element analysis and the importance of designing conformal cooling channels.