@misc{NowakMerboldEgbersetal., author = {Nowak, Torsten and Merbold, Sebastian and Egbers, Christoph and Schacht, Ralph}, title = {Novel Compact-Thermal-Model Approach to Estimate the Heat Spreading Effects of Flip-Chips on PCB regarding Laminar Flow Regimes}, series = {2019 25th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)}, journal = {2019 25th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)}, publisher = {IEEE}, isbn = {978-1-7281-2078-2}, issn = {2474-1523}, doi = {10.1109/THERMINIC.2019.8923434}, pages = {6}, abstract = {Today, electronic and thermal engineers want to figure out, which location are the most compliant one, to ensure electronic function of the system and get a reliable thermal design. Numerical simulations can help to understand thermal paths and interactions between electronic parts nearby. However, there are often time consuming, to set-up all material parameters and fluid flow properties. The usage of Compact Thermal Models (CTM) are often used for power application and can provide first solutions to heat transfer via solid substrate, thermal spreading and solid to fluid interactions. Those CTM cannot fully replace a complex fluid mechanical analysis with a Computational Fluid Dynamics (CFD) software environment. Furthermore, CTM can take place in preliminary studies during the early design phase of electronic systems within the implementation of key parameters e.g. thermal conductivity of the substrate, fluid flow velocity, power losses and different dimensions of the system. This paper continuous the experimental and numerical study of to complete an approach for CTM based thermal equivalent resistor networks with consideration of dynamic heat spreading along the substrate and laminar convective fluid interactions on typical Printed Circuit Boards (PCB) with micro-electronic Flip-Chip (FC) assemblies}, language = {en} } @misc{NowakMerboldEgbersetal., author = {Nowak, Torsten and Merbold, Sebastian and Egbers, Christoph and Schacht, Ralph}, title = {Experimentelle Studie mit numerischer Validierung von thermi-schen Kopplungs-Ph{\"a}nomenen mit in Flip-Chip-Technologie aufge-bauten Testchips auf Leiterplatten}, series = {Experimentelle Str{\"o}mungsmechanik : 27. Fachtagung 3.-5. September 2019 Erlangen}, journal = {Experimentelle Str{\"o}mungsmechanik : 27. Fachtagung 3.-5. September 2019 Erlangen}, editor = {Delgado, Antonio}, publisher = {Deutsche Gesellschaft f{\"u}r Laser-Anemometrie - German Association for Laser Anemometry GALA e.V.}, address = {Karlsruhe}, isbn = {978-3-9816764-6-4}, pages = {27.1 -- 27.8}, abstract = {In aktuellen mikro-elektronischen Systemen m{\"u}ssen verschiedene aktive und passive Bauteile auf engstem Raum miteinander auf dem Substrate (bspw. FR4-Leiterplatte) kombiniert werden. Die dabei stetig steigende Leistungsdichte bedarf einer optimierten K{\"u}hlstrategie und der Definition von konduktiven und konvektiven Entw{\"a}rmungspfade, die bereits w{\"a}hrend der Layout-Designphase der Baugruppe ber{\"u}cksichtigt werden sollten. Str{\"o}mungsmechanische Simulationen (CFD) k{\"o}nnen dabei ein erstes Abbild zur Analyse von Kopplungseffekten zwischen den W{\"a}rmequellen und der Umgebung liefern. Diese sind jedoch oft zeitaufwendig und es bedarf zumindest ein gewisses Grundverst{\"a}ndnis, um die Fluid-mechanischen Parameter, das Vernetzen der Geometrien und die gewonnenen Ergebnisse korrekt zu interpretieren. Erste analytische Ans{\"a}tze zur reduzierten Beschreibung von ungeh{\"a}usten Chips auf Leiterplattensubstrat k{\"o}nnen durch thermische Widerstandsnetzwerke abgebildet und durch Aufteilung der W{\"a}rmestr{\"o}me in Richtung Substrat (W{\"a}rmeleitung) und in Richtung des bewegten Fluides (Konvektion) n{\"a}her beschrieben werden.}, language = {de} } @misc{WargulskiNowakThieleetal., author = {Wargulski, Dan and Nowak, Torsten and Thiele, Magnus and Dobbelstein, Henrick and Schacht, Ralph and Abo Ras, Mohamad}, title = {Quality management of laser cladding processes for additive manufacturing by new methods of visualization and evaluation of thermographic data}, series = {Quantitative InfraRed Thermography Journal}, volume = {17}, journal = {Quantitative InfraRed Thermography Journal}, number = {1}, issn = {2116-7176}, doi = {10.1080/17686733.2019.1592392}, pages = {1 -- 12}, abstract = {Additive manufacturing by laser cladding is a promising tool for rapid prototyping, buildup of bionic structures and replacement part production. To ensure a constant quality of manufactured components and to shorten the development process between CAD model and suitable produced components a quality management system is inevitable. Therefore, a system has been developed to evaluate the cladding process by means of thermographic measurements. Melt pool temperature measurements by a thermal imaging camera has been processed to 2- and 3-dimensional temperature maps of the manufactured component, like a tomographic image, to easily reveal weak spots in the process and the component itself. The quality management system was tested and evaluated on several laser-cladding processes with various failures.}, language = {en} } @misc{NowakSchacht, author = {Nowak, Torsten and Schacht, Ralph}, title = {Coupling Effects during Thermo-Fluidic Analysis of Flip-Chip Devices with Peripheral Components - CFD Simulation and Experimental Study}, abstract = {The amount and concentration of electronic components and passive objects on board level increases rapidly. Furthermore, the complexity between conductive heat spreading and the use of forced thermo-fluidic coupling effects with application near behavior will become a challenge to prevent thermal bottlenecks during layout processing. For printed circuit board (PCB) designer, it would be helpful to consider the estimation of real thermal behavior without time consuming CFD analysis. A thermo-fluidic correction factor according to thermal resistance which should be a function of air velocity, power loss, and distance between active or passive components as well as the dimensions of electronic parts could help thermal engineers during layout process. Backwards, results were published for several benchmark studies with the investigation on convective and conductive interaction on commercially available microelectronic packages. Today, Flip-Chip (FC) assembly process of bare dies become being more up-to-date. A new investigation started to figure out interactions between natural and forced thermo-fluidic behavior of bare FC dies and near different components, mounted on a test PCB. To generate first rough estimations of the real fluid situation behavior current CFD modelling and simulation software are used. A suitable agreement between CFD simulation results and experimental analysis will be presented.}, language = {en} } @misc{NowakMerboldEgbersetal., author = {Nowak, Torsten and Merbold, Sebastian and Egbers, Christoph and Schacht, Ralph}, title = {Numerical Study with Experimental Validation of Thermal Coupling Phenomena with Flip-Chip Assembled Test Dies on PCB}, series = {24th INTERNATIONAL WORKSHOP on Thermal Investigations of ICs and Systems, 2018}, journal = {24th INTERNATIONAL WORKSHOP on Thermal Investigations of ICs and Systems, 2018}, publisher = {IEEE}, isbn = {978-1-5386-6759-0}, issn = {2474-1523}, doi = {10.1109/THERMINIC.2018.8593313}, pages = {5}, abstract = {Numerical Study with Experimental Validation of Thermal Coupling Phenomena with Flip-Chip Assembled Test Dies on PCB.}, language = {en} }