Laser Additive Manufacturing

Materials, Design, Technologies, and Applications

Milan Brandt

• Publisher: Woodhead Publishing
• Year: 2016
• ISBN:
  9780081004340
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

Laser Additive Manufacturing: Materials, Design, Technologies, and Applications provides the latest information on this highly efficient method of layer-based manufacturing using metals, plastics, or composite materials. The technology is particularly suitable for the production of complex components with high precision for a range of industries, including aerospace, automotive, and medical engineering.

This book provides a comprehensive review of the technology and its range of applications. Part One looks at materials suitable for laser AM processes, with Part Two discussing design strategies for AM. Parts Three and Four review the most widely-used AM technique, powder bed fusion (PBF) and discuss other AM techniques, such as directed energy deposition, sheet lamination, jetting techniques, extrusion techniques, and vat photopolymerization. The final section explores the range of applications of laser AM.

• Provides a comprehensive one-volume overview of advances in laser additive manufacturing
• Presents detailed coverage of the latest techniques used for laser additive manufacturing
• Reviews both established and emerging areas of application

Part One

Processes, technology and materials

Outline

1. Laser-aided direct metal deposition of metals and alloys

2. Powder bed fusion processes: an overview

3. Hybrid laser manufacturing

4. Surface roughness optimisation for selective laser melting (SLM): accommodating relevant and irrelevant surfaces

5. Mechanical properties of Ti6Al4V and AlSi12Mg lattice structures manufactured by Selective Laser Melting (SLM)

6. Laser additive manufacturing of ceramic components: materials, processes, and mechanisms

7. Powder bed fusion of polymers

8. Polymer nanocomposites for laser additive manufacturing

9. Laser additive manufacturing using nanofabrication by integrated two-photon polymerization and multiphoton ablation

1

Laser-aided direct metal deposition of metals and alloys

J. Mazumder The University of Michigan, Ann Arbor, MI, United States

Abstract

Breinan and Kear first reported fabrication of three-dimensional (3D) metallic components via layer-by-layer laser cladding in 1978, and a patent was subsequently issued to Brown et al. in 1982. Various groups worldwide have been working on different types of layered manufacturing techniques to fabricate near-net-shape metallic components for more than two decades. The common name “additive manufacturing” is adapted for group processes where 3D components are made layer by layer, pixel by pixel. Economist magazine recently identified additive manufacturing as the “third industrial revolution” in the 2012 April issue. Integration of lasers with multiaxis presently available computer numerical control machines, computer-aided design (CAD)/computer-aided manufacturing, sensors, and powder metal delivery through coaxial nozzles, along with the laser beam, are the main innovations for the fabrication of 3D components. Continuous corrective measures during the manufacturing process are necessary to fabricate net-shape functional parts with close tolerances and acceptable residual stress. The closed-loop direct metal deposition system, using an optical feedback loop along with a computer numerical control working under the instructions from a CAD/computer-aided manufacturing software, can produce 3D components directly from the CAD data, thus eliminating intermediate machining and considerably reducing final machining. Sophisticated science-based in situ diagnostic techniques are being developed to produce defect-free parts with acceptable properties.

Keywords

Computer-assisted design (CAD); Direct metal deposition (DMD); Homogenization design method (HDM); Laser cladding; Negative coefficient of thermal expansion (NCTE); Solid free-form fabrication (SFF)

1.1. Introduction

The well-known adage that the “early bird gets the worm” is true for any industry in this era of information technology. The cycle of consumer taste for a product is shortening, and therefore the need for an industry to go to the market with a shorter lead time is becoming more of a necessity than a desire. Concurrently, a desire for improved performance at a cheaper cost puts conflicting demands on design engineers. For example, more people want cheaper and safer air travel, which requires lighter planes with lower fuel consumption plus a higher load-carrying capacity. It is not smart to just scale up an existing design to increase capacities. Thinking out of the box is a must in order to engineer materials with properties to match the performance desired by modern consumers. Synthesis of topological design, heterogeneous computer-aided design (CAD), and direct metal deposition (DMD) offer opportunities to engineer material properties to match desired performance. Additive manufacturing has caught the imagination worldwide for the fabrication of 3D components with a desired geometry and properties. Economist magazine identified additive manufacturing as a “third industrial revolution” on the cover of the April 2012 issue [1].

1.1.1. What is direct metal deposition?

DMD is a solid free-form fabrication (SFF) technique that enables the production of realistic components with 0.01-in. accuracy and properties similar to wrought materials, with close to 100% density. Recent advances in laser-based SFF manufacturing have made possible “one-step” fabrication of useful tools for the metals and plastics industries directly from metal powders. Closed-loop DMD is a synthesis of multiple technologies including lasers, sensors, a computer numerical controlled (CNC) work handling stage, CAD/computer-aided manufacturing software and cladding metallurgy. DMD, developed in the Center for Laser-Aided Intelligent Manufacturing at the University of Michigan [2], is a laser-cladding-based process that makes fully dense free-form metallic parts layer by layer (Fig. 1.1). The key characteristic of the DMD process, which distinguishes it from other similar laser-cladding-based SFF processes, is the integrated feedback system. This system actively maintains a uniform deposition thickness, thus saving precious time after machining. In the DMD process, sensors collect light from th...

Table of contents

• Cover image
• Title page
• Table of Contents
• Related titles
• Copyright
• List of contributors
• Woodhead Publishing Series in Electronic and Optical Materials
• The role of lasers in additive manufacturing
• Part One. Processes, technology and materials
• Part Two. Design strategies and life cycle costs
• Part Three. Applications
• Index