Thermal analysis of proposed heat sink design under natural convection for the thermal management of electronics

The rapid development in the field of electronics has led to high power densities and miniaturization of electronic packages. Because of the compact size of electronic devices, the rate of heat dissipation has increased drastically. Due to this reason, the air-cooling system with a conventional heat sink is insufficient to remove large quantity of heat. A novel macro-channel ?L-shaped heat sink? is pro-posed and analyzed to overcome this problem. The thermal resistance and fluid-flow behavior under natural convection, of the novel and conventional air-cooled heat sink designs, are analyzed. Governing equations are discretized and solved across the computational domain of the heat sink, with 3-D conjugate heat transfer model. Numerical results are validated through experimentation. The effect of parameters i.e., fin height, number of fins and heat sink size, on the thermal resistance and fluid-flow are reported. Examination of these parameters provide a better physical understanding from energy conservation and management view point. Substantial increase in the thermal performance is noted for the novel ?L-shaped heat sink? compared to the conventional design

Thermal analysis and optimization of L-shape fin heat sink under natural convection using ANOVA and Taguchi

Advancement in electronic systems resulted in miniaturization and high-power densities. Therefore, the rate of heat generation in circuit board increased dramatically. To overcome the problem of overheating, numerous heat sink designs are proposed including L-shape fins heat sink. The thermo-fluidic flow behavior and temperature difference are analyzed to get better understanding of heat transfer from the sink to ambient air. Governing equations for the model of conjugate heat transfer in 3-D environment are solved and discretized across the computational domain. Numerous experiments are carried out to validate the numerical results. The effect of fin numbers, height, and heat sink size at three different input power is reported. Furthermore, ANOVA and Taguchi statistical methods are used to predict parameters that affect the heat transfer. The study revealed that fin height affects the heat transfer rate the most, and accounts for 25.3% increase in heat transfer rate. Optimization of the heat sink is carried out to ensure better efficiency of the proposed heat sink. The optimized conditions for the sink are observed to be heat sink size of 90 mm, 9 number of fins, and 33 mm of fin height

Design and validation of a fixture for positive incremental sheet forming

Incremental sheet forming is an emerging manufacturing technique in which sheet metal is formed into desired shape through the application of localized force using a hemispherical tool. Potential advantages of the process are its relatively low cost and small lead times, and these have to be balanced against the disadvantages of low dimensional accuracy and a limited understanding of the process’ internal mechanics. Incremental sheet forming system can be classified as positive, or negative, depending on whether the sheet material is progressively deformed onto a protrusion or a cavity. In negative systems, the work piece is held on a static fixture; whereas, in positive incremental sheet forming, the fixture must be incrementally lowered onto a protruding die. Although the vertical movement of positive incremental sheet forming fixtures is easily illustrated schematically, its implementation is challenging; if the descent is actuated, the motion has to be carefully coordinated with those of the forming tool; if free sliding on vertical columns, the rig must move without jamming or rocking. This article reports the development and testing of a positive incremental sheet forming fixture design that uses nylon sleeve bushes. Symmetric and asymmetric components were formed using the designed fixture, modular wooden dies and a rotating tool with multiple diameters and the results are discussed

Tensile properties of 3D-printed PLA prismatic cellular structures: an experimental investigation

Advancements in additive manufacturing have significantly increased the use of cellular structures in product development, especially in the automotive, aerospace, and biomedical industries, due to their enhanced strength-to-weight ratio and energy-absorbing capabilities. This study investigates the tensile properties of 3D-printed PLA prismatic cellular structures, focusing on the effects of fillet radius, wall thickness, and cell size on tensile strength, Young’s modulus, and strength-to-weight ratio. Using a full factorial design and ANOVA, we examined the impact and interaction of each geometrical parameter. Our findings show that triangular cellular structures exhibit a higher stiffness of 1.36 GPa and tensile strength of 24.28 MPa, resulting in a notable 5.78 MPa/gram strength-to-weight ratio. Increasing cell count and wall thickness enhances both tensile strength and Young’s modulus, whereas adding fillet radii at corners reduces these properties. Fracture behaviors are influenced by geometrical design: shorter, thicker walls lead to progressive crack propagation, while longer, thinner walls tend to fail catastrophically. Fillet radius introduction shifts the fracture initiation point from the nodes. ANOVA results indicate that wall thickness and cell size significantly affect tensile strength and Young’s modulus, contributing 36.53% and 53.54%, respectively

Experimental Investigation of Vertical Density Profile of Medium Density Fiberboard in Hot Press

This research investigates the performance of medium density fiberboard (MDF) with respect to hot press parameters. The performance of the board, type of glue, and production efficiency determine the optimum temperature and pressure for hot pressing. The actual temperature of the hot press inside the MDF board determines the properties of the final product. Hence, the optimal hot press parameters for the desired product are experimentally obtained. Moreover, MDF is experimentally investigated in terms of its vertical density profile, bending, and internal bonding under the various input parameters of temperature, pressure, cycle time, and moisture content during the manufacturing process. The experimental study is carried out by varying the temperature, pressure, cycle time, and moisture content in the ranges of 200–220 °C, 145–155 bar, 260–275 s, and 8–10%, respectively. Consequently, the optimum input parameters of a hot-pressing temperature of 220 °C, pressure of 155 bar, cycle time of 256 s, and moisture content of 8% are identified for the required internal bonding (0.64 N/mm2), bending (32 N/mm2), and increase in both the core and peak density of the vertical density profile as per the ASTM standard

Multi-Response Optimization of Tensile Creep Behavior of PLA 3D Printed Parts Using Categorical Response Surface Methodology

Three-dimensional printed plastic products developed through fused deposition modeling (FDM) endure long-term loading in most of the applications. The tensile creep behavior of such products is one of the imperative benchmarks to ensure dimensional stability under cyclic and dynamic loads. This research dealt with the optimization of the tensile creep behavior of 3D printed parts produced through fused deposition modeling (FDM) using polylactic acid (PLA) material. The geometry of creep test specimens follows the American Society for Testing and Materials (ASTM D2990) standards. Three-dimensional printing is performed on an open-source MakerBot desktop 3D printer. The Response Surface Methodology (RSM) is employed to predict the creep rate and rupture time by undertaking the layer height, infill percentage, and infill pattern type (linear, hexagonal, and diamond) as input process parameters. A total of 39 experimental runs were planned by means of a categorical central composite design. The analysis of variance (ANOVA) results revealed that the most influencing factors for creep rate were layer height, infill percentage, and infill patterns, whereas, for rupture time, infill pattern was found significant. The optimized levels obtained for both responses for hexagonal pattern were 0.1 mm layer height and 100% infill percentage. Some verification tests were performed to evaluate the effectiveness of the adopted RSM technique. The implemented research is believed to be a comprehensive guide for the additive manufacturing users to determine the optimum process parameters of FDM which influence the product creep rate and rupture time

Metrology Process to Produce High-Value Components and Reduce Waste for the Fourth Industrial Revolution

Conventionally, a manufactured product undergoes a quality control process. The quality control department mostly ensures that the dimensions of the manufactured products are within the desired range, i.e., the product either satisfies the defined conformity range or is rejected. Failing to satisfy the conformity range increases the manufacturing cost and harms the production rate and the environment. Conventional quality control departments take samples from the given batch after the manufacturing process. This, in turn, has two consequences, i.e., low-quality components being delivered to the customer and input energy being wasted in the rejected components. The aim of this paper is to create a high-precision measuring (metrology)-based system that measures the dimension of an object in real time during the machining process. This is accomplished by integrating a vision-based system with image processing techniques in the manufacturing process. Experiments were planned using an experimental design which included different lightning conditions, camera locations, and revolutions per minute (rpm) values. Using the proposed technique, submillimeter dimensional accuracy was achieved at all the measured points of the component in real time. Manual validation and statistical analysis were performed to check the validity of the system

Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor

Quartz Tuning Fork (QTF) based sensors are used for Scanning Probe Microscopes (SPM), in particular for near-field scanning optical microscopy. Highly sharp Tungsten (W) tips with larger cone angles and less tip diameter are critical for SPM instead of platinum and iridium (Pt/Ir) tips due to their high-quality factor, conductivity, mechanical stability, durability and production at low cost. Tungsten is chosen for its ease of electrochemical etching, yielding high-aspect ratio, sharp tips with tens of nanometer end diameters, while using simple etching circuits and basic electrolyte chemistry. Moreover, the resolution of the SPM images is observed to be associated with the cone angle of the SPM tip, therefore Atomic-Resolution Imaging is obtained with greater cone angles. Here, the goal is to chemically etch W to the smallest possible tip apex diameters. Tips with greater cone angles are produced by the custom etching procedures, which have proved superior in producing high quality tips. Though various methods are developed for the electrochemical etching of W wire, with a range of applications from scanning tunneling microscopy (SPM) to electron sources of scanning electron microscopes, but the basic chemical etching methods need to be optimized for reproducibility, controlling cone angle and tip sharpness that causes problems for the end users. In this research work, comprehensive experiments are carried out for the production of tips from 0.4 mm tungsten wire by three different electrochemical etching techniques, that is, Alternating Current (AC) etching, Meniscus etching and Direct Current (DC) etching. Consequently, sharp and high cone angle tips are obtained with required properties where the results of the W etching are analyzed, with optical microscope, and then with field emission scanning electron microscopy (FE-SEM). Similarly, effects of varying applied voltages and concentration of NaOH solution with comparison among the produced tips are investigated by measuring their cone angle and tip diameter. Moreover, oxidation and impurities, that is, removal of contamination and etching parameters are also studied in this research work. A method has been tested to minimize the oxidation on the surface and the tips were characterized with scanning electron microscope (SEM)

An empirical feasibility assessment for incremental sheet forming

Many sheet forming processes such [sic] hammering and spinning, have been used in the manufacturing industry for decades and consequently have strengths and weakness that are well known. In contrast, Incremental Sheet Forming (ISF) is an emerging type of forming process whose capabilities are not yet fully understood. So while it is clear that ISF processes have several advantages, such as low cost and good surface finish [sic]. It has proved difficult to define the limits of the process in terms of macro-parameters such as deformation and sheet thickness. So whereas the capabilities of many sheet metal manufacturing processes are effectively characterized by forming limit curves this has not been possible with ISF. In other words, there is a lack of methodologies for assessing the feasibility of using ISF for particular components. This thesis investigates several aspects of the ISF process and develops a quantitative methodology that allows a first approximation of the feasibility of component manufacturing using the ISF process in terms of deflection and thickness reduction. It was found that thickness reduction can be accurately modeled in terms of analytical model developed for sheet metal forming. The predictions of the method are assessed and found to give a good correspondence with measured data for the range of wall angles, materials and geometries assessed. The parameters of the proposed methodology have been determined by experimental studies of commercially pure Titanium Grade 4 (CpTi), Aluminium alloys (AA1050-H-14, AA2024-O and AA7075-O) and Stainless Steel (SS304-L) to understand the process of incremental sheet forming and its impact on the final properties of the sheet metal. The proposed method called "ISF-FCheck" uses two charts to quantify maximum strain in relation to the depth and thickness reduction. Discussion of these results has also supported the development of a more detailed understanding of the interaction of the process parameters and lead to a new theoretical and graphical representation of the ISF process.Many sheet forming processes such [sic] hammering and spinning, have been used in the manufacturing industry for decades and consequently have strengths and weakness that are well known. In contrast, Incremental Sheet Forming (ISF) is an emerging type of forming process whose capabilities are not yet fully understood. So while it is clear that ISF processes have several advantages, such as low cost and good surface finish [sic]. It has proved difficult to define the limits of the process in terms of macro-parameters such as deformation and sheet thickness. So whereas the capabilities of many sheet metal manufacturing processes are effectively characterized by forming limit curves this has not been possible with ISF. In other words, there is a lack of methodologies for assessing the feasibility of using ISF for particular components. This thesis investigates several aspects of the ISF process and develops a quantitative methodology that allows a first approximation of the feasibility of component manufacturing using the ISF process in terms of deflection and thickness reduction. It was found that thickness reduction can be accurately modeled in terms of analytical model developed for sheet metal forming. The predictions of the method are assessed and found to give a good correspondence with measured data for the range of wall angles, materials and geometries assessed. The parameters of the proposed methodology have been determined by experimental studies of commercially pure Titanium Grade 4 (CpTi), Aluminium alloys (AA1050-H-14, AA2024-O and AA7075-O) and Stainless Steel (SS304-L) to understand the process of incremental sheet forming and its impact on the final properties of the sheet metal. The proposed method called "ISF-FCheck" uses two charts to quantify maximum strain in relation to the depth and thickness reduction. Discussion of these results has also supported the development of a more detailed understanding of the interaction of the process parameters and lead to a new theoretical and graphical representation of the ISF process