Dexel-Based Simulation of Directed Energy Deposition Additive Manufacturing

Additive manufacturing is typically a flexible alternative to conventional manufacturing processes. However, manufacturing costs increase due to the effort required to experimentally determine optimum process parameters for customized products or small batches. Therefore, simulation models are needed in order to reduce the amount of effort necessary for experimental testing. For this purpose, a novel technological simulation method for directed energy deposition additive manufacturing is presented here. The Dexel-based simulation allows modeling of additive manufacturing of varying geometric shapes by considering multi-axis machine tool kinematics and local process conditions. The simulation approach can be combined with the simulation of subtractive processes, which enables integrated digital process chains

Octree Approach for Simulation of Additive Manufacturing Toolpath

Machine simulation is an effective way of checking additive manufacturing tool paths for both interferences and errors in part produced. This paper presents an algorithm to visually simulate a multi axis additive manufacturing system as it executes a process plan. Simulation results are intended to be used as a verification step before physically producing the part. Verification is particularly important for large builds of expensive materials. The algorithm uses an octree approach to efficiently model the deposition of part geometry and its changes. This paper discusses development of the simulation algorithm, including both the representation of the additive manufacturing machine and the octree data model of the part being produced

Spare parts on demand using additive manufacturing : a simulation model for cost evaluation.

Little is known about the impact of additive manufacturing in the spare part supply chain. A few studies are available, but they focus on specific parts and their applications only. A general model, which can be adapted to different applications, is nonexistent. This dissertation proposes a decision making framework that enables an interested practitioner/manager to decide whether using additive manufacturing to make spare parts on demand is economical when compared to conventional warehousing strategy. The framework consists of two major components: a general discrete event simulation model and a process of designing a wide range of simulation scenarios. The goal of the dissertation is to help verify existing as well as gain new knowledge about operations of additive manufacturing and the cost implication in the spare parts supply chains. Particularly, the proposed model enables simulation based analysis with various strategies, setups, specific parts, machines and system operating parameters. Furthermore, the process related issues of interest are the influence of building speed, building space volume, material price, machine purchase price and cool down time. Strategy related issues are multi-machine and multi-material production strategies in several setups. Also simulation investigation of different spare part stock properties are executed and analyzed by using different part size distributions. This dissertation establishes fundamental understanding of the characteristics of the additive manufacturing system for spare part supply strategies. This model could directly help the decision-making processes in whether to adopt additive manufacturing technology, and also helps the evaluation of different additive manufacturing strategies when the technology is adopted. Both decisions (adoption and strategies) are made based on cost analysis for spare parts in a broader supply chain

Effects of Defects in Laser Additive Manufactured Ti-6Al-4V on Fatigue Properties

AbstractLaser Additive Manufacturing (LAM) enables economical production of complex lightweight structures as well as patient individual implants. Due to these possibilities the additive manufacturing technology gains increasing importance in the aircraft and the medical industry. Yet these industries obtain high quality standards and demand predictability of material properties for static and dynamic load cases. However, especially fatigue and crack propagation properties are not sufficiently determined. Therefore this paper presents an analysis and simulation of crack propagation behavior considering Laser Additive Manufacturing specific defects, such as porosity and surface roughness.For the mechanical characterization of laser additive manufactured titanium alloy Ti-6Al-4V, crack propagation rates are experimentally determined and used for an analytical modeling and simulation of fatigue. Using experimental results from HCF tests and simulated data, the fatigue and crack resistance performance is analyzed considering material specific defects and surface roughness. The accumulated results enable the reliable prediction of the defects influence on fatigue life of laser additive manufactured titanium components

Additive Manufacturing Modeling and Simulation A Literature Review for Electron Beam Free Form Fabrication

Additive manufacturing is coming into industrial use and has several desirable attributes. Control of the deposition remains a complex challenge, and so this literature review was initiated to capture current modeling efforts in the field of additive manufacturing. This paper summarizes about 10 years of modeling and simulation related to both welding and additive manufacturing. The goals were to learn who is doing what in modeling and simulation, to summarize various approaches taken to create models, and to identify research gaps. Later sections in the report summarize implications for closed-loop-control of the process, implications for local research efforts, and implications for local modeling efforts

A New Finite Element Solver using Numerical Eigen Modes for Fast Simulation of Additive Manufacturing Processes

A new efficient numerical technique has been formulated for dimensional reduction and phenomenological multi-scale simulation of additive manufacturing processes using finite element analysis. This technique is demonstrated using prismatic build volumes to represent the Selective Laser Melting powder bed fusion additive manufacturing process. The Eigen modes determined as an outcome of implementation of this technique will help to reduce the time necessary for optimization of process parameters and closed loop control. In addition to thermal simulations of the Selective Laser Melting process, this technique is also applicable to the simulation of lattice structures, layered materials such as ultrasonically consolidated laminates, thin walled coatings and development of high fidelity beam and plate theories for parts made using additive manufacturing processes. A future integration of this method with analytical Eigen wavelets will provide infinite support compared to finite support provided by directional polynomial shape functions currently used for implementation of finite element strategies. The present Eigen modes will be also useful in analysis and optimization of mask projection based additive manufacturing processes.Mechanical Engineerin

Modeling, Simulation and Data Processing for Additive Manufacturing

Additive manufacturing (AM) or, more commonly, 3D printing is one of the fundamental elements of Industry 4.0. and the fourth industrial revolution. It has shown its potential example in the medical, automotive, aerospace, and spare part sectors. Personal manufacturing, complex and optimized parts, short series manufacturing and local on-demand manufacturing are some of the current benefits. Businesses based on AM have experienced double-digit growth in recent years. Accordingly, we have witnessed considerable efforts in developing processes and materials in terms of speed, costs, and availability. These open up new applications and business case possibilities all the time, which were not previously in existence. Most research has focused on material and AM process development or effort to utilize existing materials and processes for industrial applications. However, improving the understanding and simulation of materials and AM process and understanding the effect of different steps in the AM workflow can increase the performance even more. The best way of benefit of AM is to understand all the steps related to that—from the design and simulation to additive manufacturing and post-processing ending the actual application.The objective of this Special Issue was to provide a forum for researchers and practitioners to exchange their latest achievements and identify critical issues and challenges for future investigations on “Modeling, Simulation and Data Processing for Additive Manufacturing”. The Special Issue consists of 10 original full-length articles on the topic

A virtual dual-level reconfigurable additive manufacturing system for digital object fabrication

This paper proposes a virtual dual-level reconfigurable additive manufacturing system (DRAMS) for simulation and verification of deposition strategies in digital fabrication of product prototypes. The DRAMS is aimed to improve additive manufacturing (AM) processes with the concept of system reconfiguration. It consists of adaptable support and manipulation modules for deposition of fabrication materials. Topologies are investigated to determine the structures of these modules, and methods are developed to evaluate and optimize the system configuration. Simulations show that the DRAMS can not only handle prototypes of different sizes and fabrication materials, but also increase the process speed. The DRAMS offers an effective tool for simulation, verification and optimization of deposition strategies under different system configurations to improve process performance.postprintThe 21st Annual International Solid Freeform Fabrication (SFF) Symposium: An Additive Manufacturing Conference, Austin, TX., 9-11 August 2010. In Proceedings of the 21st International SFF Symposium, 2010, p. 266-27

Editorial for the Special Issue on Laser Additive Manufacturing: Design, Processes, Materials and Applications

Laser-based additive manufacturing (LAM) is a revolutionary advanced digital manufacturing technology developed in recent decades, which is also a key strategic technology for technological innovation and industrial sustainability. This technology unlocks the design and constraints of traditional manufacturing and meets the needs of complex geometry fabrication and high-performance part fabrication. A deeper understanding of the design, materials, processes, structures, properties and applications is desired to produce novel functional devices, as well as defect-free structurally sound and reliable LAM parts.The topics in this Special Issue include macro- and micro-scale additive manufacturing with lasers, such as structure/material design, fabrication, modeling and simulation, in situ characterization of additive manufacturing processes and ex situ materials characterization and performance, with an overview that covers various applications in aerospace, biomedicine, optics and energy