Download or read book Mechatronic Design and Feedback Control for Quality assured Laser Powder Bed Fusion Additive Manufacturing written by Tianyu Jiang and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite continuous technological enhancements and emerging applications of laser powder bed fusion (LPBF) additive manufacturing, the lack of repeatability and stability still represents a barrier to industrial breakthrough. This dissertation developed new mechatronic design of process monitoring and capabilities of robust control to reduce process variation and ensure part quality. By building a sensor-rich feedback-centric LPBF platform, this study enables access to crucial process signatures (e.g., powder bed temperature, melting pool image) and manipulation of various process parameters (e.g., heater power, scan velocity) to provide the opportunity for model-based controls. Leveraging the established mechatronic design, we investigated control algorithms and data interpretation frameworks for attenuating mechanical vibrations, thermal transfer fluctuations, and laser-material interaction imperfections. Specifically:We introduced a model-inverse free local loop shaping control for disturbance rejection in the laser scanning process. We proposed and verified filter designs for attenuating both narrow- and broad-band vibrations in the position output of the scanner, leading to higher accuracy of part geometry. We proposed a model-based multi-zone heating control algorithm for minimizing the powder bed temperature deviation in the presence of part-geometry induced cross-layer thermal disturbance, leading to a more homogeneous part mechanical property. We created an image analytics framework for defect identification, part quality evaluation, and process signature filtering, which paves the road towards online implementable laser-material interaction control.
Download or read book Control oriented Modeling and Multirate Feedback Control in Laser Powder Bed Fusion Additive Manufacturing written by Dan Wang and published by . This book was released on 2020 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: A high-precision additive manufacturing process, laser powder bed fusion (LPBF) has enabled unmatched agile manufacturing of a wide range of products from engine components to medical implants. While finite element modeling and closed-loop control have been identified key for predicting and engineering part qualities in LPBF, existing results in each realm are developed in opposite computational architectures wildly different in time scale. This dissertation builds a first-instance closed-loop simulation framework by integrating high-fidelity finite element modeling with feedback controls originally developed for general mechatronics systems. By utilizing the output signals (e.g., melt pool width) retrieved from the finite element model (FEM) to directly update the control signals (e.g., laser power) sent to the model, the proposed closed-loop framework enables testing the limits of advanced controls in LPBF and surveying the parameter space fully to generate more predictable part qualities. Along the course of formulating the framework, we build and refine an FEM of the thermal response in LPBF and verify the FEM by comparing its results with experimental and analytical solutions. Thereafter, we use the FEM to understand the melt-pool evolution induced by the thermomechanical interactions in LPBF. In addition, we build a new Hammerstein mixed-fidelity model to capture more of the complex spatiotemporal thermal dynamics. Under the architecture of the closed-loop simulation, we discuss general loop-shaping algorithms and specifically develop a multirate fractional-order repetitive control (RC) algorithm that addresses an intrinsic RC limitation when the exogenous signal frequency cannot divide the sampling frequency of the sensor. We also investigate the model inversion techniques---an important piece of the loop-shaping control---and build an H infinity-based optimal inversion that attains model accuracy at the frequency regions of interest while constraining noise amplification elsewhere to guarantee system robustness. Besides, we analyze spectral properties of the closed-loop signals under sample-data control and show that the single-rate high-gain feedback cannot reject disturbances near and beyond the Nyquist frequency. From there, we provide a case study on applying an RC algorithm to greatly attenuate periodic thermal variations in LPBF.
Download or read book Digitalization of design for support structures in laser powder bed fusion of metals written by Katharina Bartsch and published by Springer Nature. This book was released on 2023-02-18 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Additive manufacturing is considered a key technology for digital production. However, several barriers towards the broad industrial application exist, e.g. the associated cost and the required experience regarding the manufacturing process. To eradicate these barriers, the complete digitalization of the value creation process is needed. In this thesis, a digital, automated support structuredesign procedure is developed. Topology optimization is used for design rule determination, and the space colonization algorithm is adapted for the automated design. The validity of the procedure is proven experimentally, revealing sufficient mechanical performance alongside cost reduction at medium to large production scales.
Download or read book Fundamentals of Laser Powder Bed Fusion of Metals written by Igor Yadroitsev and published by Elsevier. This book was released on 2021-05-23 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser powder bed fusion of metals is a technology that makes use of a laser beam to selectively melt metal powder layer-by-layer in order to fabricate complex geometries in high performance materials. The technology is currently transforming aerospace and biomedical manufacturing and its adoption is widening into other industries as well, including automotive, energy, and traditional manufacturing. With an increase in design freedom brought to bear by additive manufacturing, new opportunities are emerging for designs not possible previously and in material systems that now provide sufficient performance to be qualified in end-use mission-critical applications. After decades of research and development, laser powder bed fusion is now enabling a new era of digitally driven manufacturing. Fundamentals of Laser Powder Bed Fusion of Metals will provide the fundamental principles in a broad range of topics relating to metal laser powder bed fusion. The target audience includes new users, focusing on graduate and undergraduate students; however, this book can also serve as a reference for experienced users as well, including senior researchers and engineers in industry. The current best practices are discussed in detail, as well as the limitations, challenges, and potential research and commercial opportunities moving forward. - Presents laser powder bed fusion fundamentals, as well as their inherent challenges - Provides an up-to-date summary of this advancing technology and its potential - Provides a comprehensive textbook for universities, as well as a reference for industry - Acts as quick-reference guide
Download or read book Innovative Product Development by Additive Manufacturing 2021 written by Roland Lachmayer and published by Springer Nature. This book was released on 2022-11-12 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book consists of a collection of papers from a corresponding conference regarding additive manufacturing. The yearly conference used to be held in German under the title: “Konstruktion für die Additive Fertigung.” The topics are: • Design and optimization • Simulation, validation and quality assurance • Specifications, potentials and solutions/div
Download or read book Additive Manufacturing of Mechatronic Integrated Devices written by Friedrich Wilhelm Proes and published by Springer Nature. This book was released on 2022-09-23 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation a new process chain for the Additive Manufacturing of Mechatronic Integrated Devices (AMMID) is described, which provides a new way to manufacture 3-dimensional electronic devices based on the selective laser sintering (SLS) process using laser direct structuring (LDS) and metallization. The AMMID process chain meets the rising demand for highly functionalized parts, increasing individualization and shortening development cycles for electronic products. The development for this process chain is based on an extensive literature review that indicates that an SLS-based process chain has great potential to produce 3-dimensional electronic devices with properties and with the future perspective of being suitable for an individualized mass production. The biggest, initial, technical hurdle is an unstable SLS process using a conventional LDS additive. The compound of SLS material and LDS additive was analyzed with DSC, which shows that the additive changes the melting behavior of the polymer by reducing the sintering window. A fine metal powder as an alternative additive affects the sintering window less and enables a stable process. To choose a suitable particle size and content for the metal powder an analytical material model is provided, that predicts the additive particle distribution within the material. This material model deepens the understanding of the activation mechanism during laser activation, provides hands-on information for powder preparation and it is applied for the design of the experiment for the development of the process chain with the new material. Preliminary experiments are conducted along with the insights of the material model, which prove that redeposition is the main activation mechanism during laser activation with fine metal powders. Based on this, the process chain is developed, starting with a determination of a suitable additive content. A suitable material composition of a PA12 powder containing 2 wt.% of a copper powder with a mean particle diameter of 3.5 μm was identified. With regard to the laser activation, working laser parameters are developed (working parameter set feasible for all used post-process treatments: PRF = 1 kHz, dh = 25 μm, vs = 25 mm/s, tl = 20ns and P = 1.07 W). In this parameter development it is shown, that only closely located laser spots, enabling interaction of the laser pulses, are capable of activating the surface, while single laser pulses under applied conditions are not. By adding a post-process treatment as additional process step into the process chain, the quality of metallization and the size of design features could be improved. Chemical smoothing resulted in a complete reduction of unwanted metallization on non-activated surfaces. Conductor tracks with the minimal width of 300 μm could be realized. The process chain could be applied to demonstrator parts such as a drone housing and a PSU panel of an aircraft. Thus, this dissertation has raised the technology readiness level (TRL) from TRL2 to TRL6. Finally, an economic consideration provides insights on the cost structure of parts produced with the AMMID process. A comparison of AMMID and injection molding shows economic viability for small lot sizes, 400 parts in case of the drone housing and 150 parts in case of the PSU panel. Finally, the analysis of the cost structure gives advice which future developments in the process chain have the greatest effect on costs and provides prioritization.
Download or read book Laser Additive Manufacturing of Metallic Materials and Components written by Dongdong Gu and published by Elsevier. This book was released on 2022-12-07 with total page 824 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser Additive Manufacturing of Metallic Materials and Components discusses the current state and future development of laser additive manufacturing technologies, detailing material, structure, process and performance. The book explores the fundamental scientific theories and technical principles behind the elements of laser additive manufacturing, touching upon scientific and technological challenges faced by laser additive manufacturing technology. This book is suitable for those who want to further "understand and "master laser additive manufacturing technology and will expose readers to innovative industrial applications that meet significant demand from aeronautical and astronautical high-end modern industries for low-cost, short-cycle and net-shape manufacturing of structure-function integrated metallic components. With the increasing use of industrial applications, additive manufacturing processes are deepening, with technology continuing to evolve. As new scientific and technological challenges emerge, there is a need for an interdisciplinary and comprehensive discussion of material preparation and forming, structure design and optimization, laser process and its control, microstructure and performance characterization, and innovative industrial applications, hence this book covers these important aspects. - Highlights an integration of material, structure, process and performance for laser additive manufacturing of metallic components to reflect the interdisciplinary nature of this technology - Covers cross-scale structure and performance coordination mechanisms, including micro-scale material microstructure control, meso-scale interaction between laser beam and particle matter, and macro-scale precise forming of components and performance control - Explores fundamental scientific theories and technical principles behind laser additive manufacturing processes - Provides innovation elements and strategies for the future sustainable development of additive manufacturing technologies in terms of multi-materials design, novel bio-inspired structure design, tailored printing process with meso-scale monitoring, and high-performance and functionality of printed components
Download or read book Laser Based Additive Manufacturing of Metal Parts written by Linkan Bian and published by CRC Press. This book was released on 2017-08-09 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-Based Additive Manufacturing (LBAM) technologies, hailed by some as the "third industrial revolution," can increase product performance, while reducing time-to-market and manufacturing costs. This book is a comprehensive look at new technologies in LBAM of metal parts, covering topics such as mechanical properties, microstructural features, thermal behavior and solidification, process parameters, optimization and control, uncertainty quantification, and more. The book is aimed at addressing the needs of a diverse cross-section of engineers and professionals.
Download or read book Design for Additive Manufacturing written by Roland Lachmayer and published by Springer Nature. This book was released on with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Powder Bed Fusion of Additive Manufacturing Technology written by Di Wang and published by Springer Nature. This book was released on 2023-10-06 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book systematically introduces the powder bed laser melting technology and its application and summarizes the author's team's experience in scientific research, engineering development, and data accumulation in recent 15 years. It includes in-depth theoretical analysis and a lot of engineering experience in equipment debugging, process development, and material testing. The book takes the powder bed laser melting technology as the object and divides the content into 15 chapters. It is used as technical learning materials for researchers and engineering development personnel engaged in metal 3D printing.
Download or read book Additive Manufacturing written by International Organization for Standardization and published by . This book was released on 2019 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Feedback Control Loops for the Laser Powder Bed Fusion Machine written by and published by . This book was released on 2021 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Additive Manufacturing written by International Organization for Standardization and published by . This book was released on 2019 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tailoring Mechanical Properties and Porosity in Laser Powder Bed Fusion by Spatial Manipulation of Feedstock Composition written by Bethany Rose Lettiere and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Additive manufacturing (AM) is capable of forming complex geometries, can build custom products, and offers greater versatility than many conventional manufacturing processes. Metal AM has revolutionized the design and production of rocket engines, enabled lightweight robotics and drones, and created heat exchangers that improve the efficiency of energy conversion systems. Typically, the feedstock for metal AM is a single alloy powder, metal powder, or a stochastic mixture of alloys. The design space of AM can be expanded by techniques for local manipulation of the powder feedstock, thereby enabling the tailoring of composition or microstructure gradients to improve mechanical or thermal properties. Current methods for local manipulation of the feedstock incorporate hopper- or vacuum-based methods with spatial deposition resolution on the order of 500 [mu]m and typically require a secondary recoating step after depositing the material, further limiting the resolution and fidelity of property. In this thesis, a new hybrid AM technique combining inkjet deposition followed by laser powder bed fusion (LPBF) is studied, and the technique is demonstrated in exemplary contexts. To begin, a rapid experimental workflow is developed, whereby etched metal substrates are used as templates for spreading a thin layer of metal powder; spreading is preceded by inkjet deposition onto the wells and is followed by laser scanning to form a solid material with tailored characteristics. This workflow facilitates an understanding of the influence of additive concentration, laser power, and scan speed on the process. Using this workflow, the thesis: (1) assesses the resolution (~ 200 [mu]m) and limitations of the hybrid inkjet-LPBF process; (2) demonstrates the fabrication of porous stainless steel using a polymer-based ink as the deposited additive, achieving spatially controlled porosity upwards of 8% locally with pore sizes of 250-800 [mu]m2 and a spatial resolution of ~ 400 [mu]m; (3) demonstrates spatial tailoring of the hardness of stainless steel using an ink with carbon black as the additive, achieving a local increase in the microhardness from a control of 178 HV to 196.6 HV with a spatial resolution of 250 [mu]m. In the case of porosity control, a scaling model of thermal effects, combined with an understanding of the melt pool's flow and stability, rationalizes the experimental outcomes and the process parameter space. This thesis validates the multi-material inkjet-laser process for high-resolution, spatially graded metal AM. These findings lay the foundation for a hybrid inkjet-LPBF fusion system to develop high-precision components and its use for rapid alloy development in metal AM.
Download or read book Additive Manufacturing written by and published by . This book was released on 2019 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Engineering of Temperature Profiles for Location specific Control of Material Micro structure in Laser Powder Bed Fusion Additive Manufacturing written by George Lewandowski and published by . This book was released on 2020 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work explores new capabilities of recently emerged adaptive multi-beam laser power sources to optimally shape laser power spatial distribution at powder material during metallic laser powder bed fusion additive manufacturing. Conventional laser additive manufacturing (LAM) systems use a highly localized laser beam for powder material melting resulting in strong temperature gradients inside the heat affected zone (HAZ) leading to formation of columnar material grain structure having highly anisotropic mechanical properties. Beam shaping with multi-beam laser power source provides opportunities for on demand and location-specific altering grain structure from columnar to equiaxed resulting in more isotropic mechanical properties of LAM fabricated parts. In this work we perform numerical simulations of theLAM process using a reduced complexity analytical heat transfer solution in order to optimize multi-beam configurations leading to the desired transitioning from columnar to equiaxed grain morphology. The beam shaping optimization was performed using a stochastic parallel gradient descent optimization of the introduced performance metrics. The results demonstrate the possibility to significantly increase the fraction of equiaxed grains in the solidified powder material using optimal positioning and laser power control of multiple laser focal spots during LAM.
Download or read book Additive manufacturing Design Part 1 Laser based powder bed fusion of metals written by and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
