Design Of Cooling Channels Research Articles

A Simulation Study on Warpage Analysis of Injection Moulded Plastic Part

A part to be injection molded is evaluated by simulation for warpage analysis. The plastic part is a supporting plate to be used in the oil filter and it’s made out of nylon material. The effect of various parameters from design to processing of plastic parts is considered and validated by simulation results. The research involved in this was designing mould, computer-aided engineering, simulation analysis, and determination of plastic part processing conditions. In this work PA66 (Grade name – Zytel 70G13HS1LNC010) material is used and the material contains 13 % of fiber. Fiber orientation is nothing but the distribution of plastic melt inside the cavity and it also plays important role in deciding the warpage of part. The effect of process parameters on part warpage is investigated from various aspects in comparison with the conventional runner system. Hot runner mould system with innovative cooling channel designs is good results-driven. Results of simulations reveal that elevated mould temperature reduces the unwanted freezing time during the injection phase and thus improves mouldability and enhances part quality. Under similar mould temperature conditions, the effect of process parameters on warpage decreases according to the following order, packing time, packing pressure, melt temperature, injection pressure, and cooling time respectively.

A Numerical and Experimental Investigation of the Thermal Behavior of a Permanent Metal Mold with a Conventional Cooling Channel and a New Cooling Channel Design

A Numerical and Experimental Investigation of the Thermal Behavior of a Permanent Metal Mold with a Conventional Cooling Channel and a New Cooling Channel Design

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.

Investigation of an inverse thermal injection mould design methodology in dependence of the part geometry

The production of injection moulded components with low shrinkage and warpage is a constant challenge for manufacturers. The thermal design of the injection mould plays an important role for the achievable quality, especially the placement of the cooling channels. This design is usually based on empirical knowledge of the mould designers. The construction is supported iteratively by injection moulding simulations. In the case of thick-walled plastic optics with big wall thickness jumps, the shrinkage is compensated by injection compression moulding. In this process, the thin-walled areas freeze earlier and the necessary compression pressure introduces stresses into these areas which reduces the optical performance. An adapted cooling channel design can reduce these problems. At the IKV, Institute for Plastics Processing in Industry and Crafts at the RWTH Aachen University, a methodology was developed which inversely calculates the cooling requirement of the moulded part A demand-oriented cooling channel system is derived based on the computed results. The aim of the research projects is to minimise displacement and internal stresses by temperature control of the moulded parts according to the demand. In this paper, the methodology is applied to three different geometries, representing three classical parts for the injection moulding process. Three different quality areas in the mould for the inverse optimisation are defined and investigated. For each geometry the cooling channel designs are then validated in injection moulding simulations based on the results from the thermal optimisation. It can be shown that for different component geometries and thicknesses, different quality areas are advantageous and decrease the maximum warpage of the parts. For thin-walled ribbed components, a 2D approach leads to a 15% smaller displacement, for components with wall thickness jumps, all investigated quality ranges show no differences in displacement, but a surface in the middle of the part is preferred due to a 3 °C lower standard deviation of the temperature distribution.

A current state of art applied to injection moulding manufacturing process – A review

Abstract Injection moulding (IM) appears to be one of the most important techniques for manufacturing plastics products worldwide. As IM is a complicated process, so it is technically very difficult to take into account all the changes taking place during the process. To enhance efficiency of the process and to have consistent product quality, proper input parameter’s setting is critically important. The numbers of input process parameters are: melt temperature, mold temperature, injection pressure, injection speed, injection time, holding pressure, holding time and cooling time. The responses/output may be mechanical properties, defects e.g., warpage, shrinkage, sink mark, residual thermal stress etc., and aesthetic requirement for example surface finish/roughness. Literature review shows that most of the researchers have optimized the process parameters and established a correlation between the parameters and the behavior of the material under investigation. Others performed optimization research regarding some specific areas of IM viz. cooling channel design, location of the gate, runner system design etc. Some of the studies were focused on monitoring control system to monitor the process during production to ensure quality and minimize the defects. Researchers have used many different techniques to model and optimize the IM manufacturing process. These techniques include mathematical modelling, simulation, design of experiments (DOE) and artificial intelligence (AI). Some of the examples of these techniques are Taguchi method, evolutionary algorithm (EA), artificial neural networks (ANN), genetic algorithms (GA), fuzzy logic, response surface methodology (RSM), particle swarm optimization (PSO), analysis of variance (ANOVA) etc. This paper aims to review and present the various studies concerning the process parameters and their influence over the quality of product. Throughout this review, the process parameters, response, material used and the technique applied to optimization research in the field of IM are highlighted.

Tool lifetime when drilling Inconel 718 in dependence of the cooling channel design –Influence of the clearance angle, the channel diameter, number, and shape

When drilling Inconel 718, the drills are exposed to high mechanical and thermal loads. The cutting zone is located inside the workpiece, whichmakes it challenging to provide sufficient metalworking fluid to the cutting zone. To solve this, drills with internal cooling channels are commonly used. However, no standard on the design of those channels exists. In this work, the influence of different cooling channel designs and different second tool orthogonal clearance angles on tool life, process forces and bore quality have been investigated experimentally. The results reveal that tool lifetime can be influenced in particular by the size of the cooling channels.

Review of Gas Turbine Internal Cooling Improvement Technology

Abstract The higher firing temperature reflects the higher efficiency of the gas turbine. However, using higher temperatures is limited as it may cause a rupture, bending, or failure of the turbine blades. Hence, the development of an effective internal cooling system of the gas turbine blade is essential. At the same time, it is necessary to ensure the lowest possible penalty on the thermodynamics performance cycle. Researchers are working over the years to find out the efficient cooling channel design with high transfer while the lowest pressure drop. They ran several cases both numerically and experimentally. This paper reviews the published research in the various methods of gas turbine internal cooling, such as using rib turbulators, dimples, jet impingement, pin fins, and guide vane, of the gas turbine blade.

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.

Optimization and Design of Regenerative Cooling Channel for Scramjet Engine

In this paper, the optimization model and numerical calculation verification model of the regenerative cooling channel structure of the scramjet engine are established, and the structural parameters of the regenerative cooling channel of the scramjet engine are optimized and numerically verified. The results show that the established optimization model of the regenerative cooling channel structure of the scramjet engine can meet the design requirements; after the structure optimization, the wall temperature change trend is basically the same as the original design change trend, and the overall temperature is low; the central flow calculated by the optimized configuration calculation, but the pressure loss of kerosene in the cooling channel is small. The oil temperature and convection heat transfer coefficient are large; the inner wall and fins of the optimized configuration are thinner, the channel height is higher, and the width is narrower, which can effectively increase the convection heat transfer efficiency of the cooling channel, which can ensure that the material temperature is not Exceeding its maximum allowable temperature can make the pressure loss relatively low.

Operation of normal-conducting rf cavities in multi-Tesla magnetic fields for muon ionization cooling: A feasibility demonstration

Ionization cooling is the preferred method for producing bright muon beams. This cooling technique requires the operation of normal conducting, radio-frequency (RF) accelerating cavities within the multi-tesla fields of DC solenoid magnets. Under these conditions, cavities exhibit increased susceptibility to RF breakdown, which can damage channel components and imposes limits on channel length and transmission efficiency. We present a solution to the problem of breakdown in strong magnetic fields. We report, for the first time, stable high-vacuum, copper cavity operation at gradients above 50 MV/m and in an external magnetic field of three tesla. This eliminates a significant technical risk that has previously been inherent in ionization cooling channel designs.

Investigation of the roughness variation along the length of LPBF manufactured straight channels

ABSTRACT Conformal cooling channels, made by the laser powder bed fusion process, are a promising design strategy for optimising cooling and process control of manufacturing tools and injections moulds. The addition of internal features such as corrugations and ribs are becoming an interesting addition to the cooling channel designs. Internal surfaces of laser powder bed fusion components have an inherent process-induced roughness. The roughness may affect the flow in the channels and may affect the addition of internal features by changing the actual geometry of the channels. This work seeks to characterise the variation of the internal surface roughness along the length of seven straight channels, manufactured using the laser powder bed fusion process, by utilising X-ray CT and image analysis. The characterisation showed that the surface roughness varied discontinuously along the length of the channels and that the roughness magnitudes and roughness variations along the channel lengths were dependent on the orientation of the channels with respect to the build direction. Therefore, the actual geometries of multiple, nominally equal, embedded internal features would vary differently from nominal design, dependent on the location of the feature along the channel length and orientation in the channel.

Machining Accuracy Enhancement of a Machine Tool by a Cooling Channel Design for a Built-in Spindle

This study presents a multiphysics simulation analysis that was performed for the cooling channel of a built-in spindle. The design of experiments (DOE) method was employed to optimize the dimension of the cooling channel, and a practical machining experiment was performed to validate the effect of the design. In terms of the temperature, pressure drop, thermal deformation, manufacturing cost, and initial cost considerations, the paralleling type cooling channel of the front bearing and the helical type cooling channel of the motor were adopted in the study. After the optimal design of the cooling channel was applied, the bearing temperature was reduced by a maximum decrease of 6.7 °C, the spindle deformation decreased from 53.8 μm to 30.9 μm, and the required operational time for attaining the steady state of the machine tool was shortened from 185.3 min to 132.6 min. For the machining validation, the spindle with the optimal cooling channel design was employed for vehicle part machining, the flatness of the finished workpiece was increased by 61.3%, and the surface roughness (Ra) was increased by 52%. According to the findings for the optimal cooling channel, when the spindle cooling efficiency is increased by the optimal cooling channel design, the thermal deformation and warm-up period can be reduced effectively, and the machining precision can be enhanced. This method is an efficient way to increase the accuracy of a machine tool.

Cooling Channel Design for a Built-in Spindle of a Machine Tool

The generating heat from bearings and a motor of a built-in high rotating speed spindle of a machine tool has to be dissipated to attain high machining accuracy. In this study, a machine tool with a coolant cooling system for a high rotating speed spindle was investigated. The cooling channel designs in terms of channel pattern and dimensions by the design of experiment method (DOE) on the cooling effect of the spindle were studied. By the optimized cooling channel design, the cooling efficiency can be improved by 57.6% and the generating temperature in the spindle can be reduced by 25.9°C.

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.

Performance improvement of hot stamping die for patchwork blank using mixed cooling channel designs with straight and conformal channels

Although the cooling channel is a crucial factor for improving the performance of a hot stamping die, only a limited number of studies have been conducted concerning its design technology for patchwork blanks. In this study, a mixed cooling channel (MCC) is proposed to improve the cooling performance of the hot stamping die for patchwork blanks. The MCC is a combination of the straight cooling channel (SCC) and conformal cooling channel (CCC). The cooling capacity, average temperature, standard deviation, and figure of merit (FOM) of the SCC, CCC, and MCC are estimated by conducting three-dimensional transient thermo-fluid simulations. The optimum mass flow ratio of the MCC is determined to be 10% considering the cooling capacity, average temperature, and standard deviation. The MCC exhibits superior cooling performance to the SCC and CCC for all performance indicators because it effectively cools both the heat accumulated patch and the wide blank. In addition, the daily production of the MCC is 7.6–9.0% greater than that of the SCC, and 5.8–6.8% greater than that of the CCC.

Effect of geometry parameters on the hydrocarbon fuel flow rate distribution in pyrolysis zone of SCRamjet cooling channels

Hypersonic air-breathing propulsion (>Mach 5) based on SCRamjet promotes the revolutions of both military and civilian applications. However, the engine thermal protection is seriously challenged due to high Mach number. One of the key problems is mal-distribution of hydrocarbon fuel in regenerative cooling channels under the complex thermal boundaries and channel geometry, which may cause structural failure. To improve the cooling channel design and achieve better fuel flow distribution, the effect of channel geometry parameters on flow distribution in pyrolysis zone is numerically studied. Both geometry induced and heat flux induced flow mal-distribution are concerned. The study indicates that the flow and heat transfer features in pyrolysis zone of parallel channels differs with those in non-pyrolysis zone. The flow distribution deviations in pyrolysis zone are lower. When the channel aspect ratio varies, thermal stratification dominates flow distribution more than the variation of heat flux on heated surface in pyrolysis zone, which is opposite of that in non-pyrolysis zone. Besides, thinner rib and smaller total flow area achieve better cooling performance while consuming less fuel chemical heat sink. The results help to conclude possible references to the design of cooling channels with fuel pyrolysis considered.

Performance of die cooling system design in hot stamping process

ABSTRACTThis study examined the cooling channel design of hot stamping tools to provide an effective method for the cooling system design. A flat plate tool model was investigated to determine the effects of cooling channel and manufacturing parameters on the cooling rate and cooling uniformity of the sheet blank by conducting finite element analysis. The fractional factor method was also employed to establish empirical equations for describing the cooling performance of the flat plate model. The empirical equations established in the present study can efficiently predict the cooling rate and cooling uniformity of sheet blanks with various cooling channel designs, and are of much help in providing an initial cooling system design for hot stamping tools. To validate the accuracy of the finite element analysis, experiments on sheet blank cooling process were conducted using the proposed flat plate tool design. The cooling processes were cyclically repeated for the validation of blank temperature distribution. The temperature evolution of sheet blanks obtained from the finite element simulations agree well with the experimental results and the validity of the finite element model is confirmed, and thus the effectiveness of the empirical equations is established.

Advancements in Design And Fabrication of Conformal Cooling Channels for Improvement in Plastic Injection Molding Process

Advancements in Design And Fabrication of Conformal Cooling Channels for Improvement in Plastic Injection Molding Process

Prevent weld line defects on an automotive crash pad by local heating and cooling with 3D printed insert core

A 3D printed insert core, which embeds a heater and cooling channel by additive manufacturing, can lead to conformal heating and cooling on the vicinity of the defect area in the injection molding process. The purpose of this study is to design a 3D printed insert core of an injection molding tool to reduce weld line defects on automotive crash pads with a high standard of appearance. In this study, heat transfer experiments were conducted to compare the efficiency of two different types of building up method for insert core. A heat transfer simulation was conducted to design a heater and cooling channel for the conformal surface temperature of the insert core and for thermal response efficiency. The Taguchi optimization technique was used to investigate the influence of the heater and cooling channels design parameters on the surface temperature during the heating and cooling stage. The effects of the insert core surface temperature to eliminate the weld line defects were evaluated by a series of injection molding experiments for manufacturing the automotive crash pad. The results of the experiments indicate that the developed 3D printed insert core can greatly improve the uniformity of the surface temperature in the defect area and reduce the weld line of the manufactured product.

Thermal Loads and Cooling Design for ITER in-Port Low Field Side Reflectometer Diagnostic System

The current design for the ITER Low Field Side Reflectometer (LFSR) diagnostic system contains six circular waveguides that function as both launch and receive antennas. The front end of LFSR system, interfacing with the plasma facing DFW and its supporting diagnostic shielding Modules (DSM), is integrated into Equatorial Port Plug 11(EPP#11). In-vessel LFSR configuration is mainly divided into two sections, i.e. Front Antenna Unit (FAU) and in-vessel Transmission Line (TL) components. During plasma normal operation, the 14 MeV neutrons from D-T fusion reactions penetrate into the port plug and LFSR components. Neutronics code ATTILA is used for assessing the volumetric heating of in-vessel components. The maximum normal heat load due to radiation and the charge exchange from plasma is 0.35 MW/m2, which has to be applied on those surfaces affected by a viewing factor consistent with the aperture surface position and orientation. The front antenna unit (FAU) needs the active cooling to handle the radiant and nuclear heating from the plasma. Due to the specific viewing aperture layout at the front-end of in-vessel LFSR, the cooling channel design is challenging. The thermal-hydraulic iterations are performed to achieve the desirable temperature distribution of the water cooled front antenna units. Finally, the progressive ratcheting effects of the FAU subjected to cyclic thermal loading are examined by the preliminary non-linear elastic-plastic analysis.