3,026 research outputs found
From 3D Models to 3D Prints: an Overview of the Processing Pipeline
Due to the wide diffusion of 3D printing technologies, geometric algorithms
for Additive Manufacturing are being invented at an impressive speed. Each
single step, in particular along the Process Planning pipeline, can now count
on dozens of methods that prepare the 3D model for fabrication, while analysing
and optimizing geometry and machine instructions for various objectives. This
report provides a classification of this huge state of the art, and elicits the
relation between each single algorithm and a list of desirable objectives
during Process Planning. The objectives themselves are listed and discussed,
along with possible needs for tradeoffs. Additive Manufacturing technologies
are broadly categorized to explicitly relate classes of devices and supported
features. Finally, this report offers an analysis of the state of the art while
discussing open and challenging problems from both an academic and an
industrial perspective.Comment: European Union (EU); Horizon 2020; H2020-FoF-2015; RIA - Research and
Innovation action; Grant agreement N. 68044
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Converting a CAD Model into a Manufacturing Model for the Components Made of a Multiphase Perfect Material
To manufacture the component made of a multiphase perfect material (including homogeneous
and multi heterogeneous materials), it CAD model should be processed and converted into
layered manufacturing model for further transformation of numerical control (NC) coding. This
paper develops its detailed approaches and corresponding software. The process planning is made
first and includes: (1) determining the build orientation of the component; and (2) slicing the
component into layers adaptively according to different material regions since different materials
have different optimal layer thickness for manufacturing. After the process planning, the layered
manufacturing models with necessary information, including fabrication sequence and material
information of each layer, are fully generated.Mechanical Engineerin
Multiresolution Layered Manufacturing
PURPOSE: Two-photon polymerization (TPP) has become one of the most popular techniques for stereolithography at very high resolutions. When printing relatively large structures at high resolutions, one of the main limiting factors is the printing time. The goal of this work is to present a new slicing algorithm to minimize printing times. DESIGN/METHODOLOGY/APPROACH: Typically, slicing algorithms used for TPP do not take into account the fact that TPP can print at a range of resolutions (i.e. with different heights and diameters) by varying parameters such as exposure time, laser power, photoresist properties, and optical arrangements. This work presents Multiresolution Layered Manufacturing (MLM), a novel slicing algorithm that processes 3D structures to separate parts manufacturable at low resolution from those that require a higher resolution. FINDINGS: MLM can significantly reduce the printing time of 3D structures at high resolutions. The maximum theoretical speed-up depends on the range of printing resolutions, but the effective speed-up also depends on the geometry of each 3D structure. RESEARCH LIMITATIONS/IMPLICATIONS: MLM opens the possibility to significantly decrease printing times, potentially opening the use of TPP to new applications in many disciplines such as microfluidics, metamaterial research or wettability. ORIGINALITY/VALUE: There are many instances of previous research on printing at several resolutions. However, in most cases, the toolpaths have to be manually arranged. In some cases, previous research also automates the generation of toolpaths, but they are limited in various ways. MLM is the first algorithm to comprehensively solve this problem for a wide range of true 3D structures.NANO3D (a BEWARE Fellowship from the Walloon Region, Belgium, part of the Marie Curie Programme of the ERC). IAP 7/38 MicroMAST (Interuniversity Attraction Poles Programme from the Belgian Science Policy Office, the Walloon Region and the FNRS)
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Biomimetic Design and Fabrication of Interior Architecture of Tissue Scaffolds Using Solid Freeform Fabrication
Modeling, design and fabrication of tissue scaffolds with intricate architecture,
porosity and pore size for desired tissue properties presents a challenge in tissue engineering.
This paper will present the details of our development in designing and fabrication of the
interior architecture of scaffolds using a novel design approach. The Interior Architecture
Design (IAD) approach seeks to generate scaffold layered freeform fabrication tool path without
forming complicated 3D CAD scaffold models. This involves: applying the principle of layered
manufacturing to determine the scaffold individual layered process planes and layered contour;
defining the 2D characteristic patterns of the scaffold building blocks (unit cells) to form the
Interior Scaffold Pattern; and the generation of process tool path for freeform fabrication of
these scaffolds with the specified interior architecture. Feasibility studies applying the IAD
algorithm to example models and the generation of fabrication planning instructions will be
presented.Mechanical Engineerin
Research Towards High Speed Freeforming
Additive manufacturing (AM) methods are currently utilised for the manufacture of prototypes and low volume, high cost parts. This is because in most cases the high material costs and low volumetric deposition rates of AM parts result in higher per part cost than traditional manufacturing methods. This paper brings together recent research aimed at improving the economics of AM, in particular Extrusion Freeforming (EF).
A new class of machine is described called High Speed Additive Manufacturing (HSAM) in which software, hardware and materials advances are aggregated. HSAM could be cost competitive with injection moulding for medium sized medium quantity parts. A general outline for a HSAM machine and supply chain is provided along with future required research
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Process Planning Based on User Preferences
Typical approaches to adaptive slicing in previous literature have typically used surface finish
requirements to control the slicing process. As a result, slice schemes improve the part's surface
quality, but do not enable explicit trade-offs between finish and build time. The purpose of this
article is to present a process planning method that enables the preferences of the user for surface
finish, build time, and accuracy to control how trade-offs are made in a process plan. A multiobjective goal formulation is used by this method to evaluate how well user preferences are met by
a process plan. This method consists of three modules, for determining part orientation, for slicing
the part, and for determining other parameter values. An example with several scenarios
representing different user preferences is provided to illustrate the process planning method.Mechanical Engineerin
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Systems Issues in Solid Freeform Fabrication
This paper is concerned with the systems aspects of the Solid Freeform Fabrication (SFF) technology, i.e., the issues that deal with getting an external geometric CAD model to automatically control the physical layering fabrication process as directly as possible, regardless ofthe source of the model. The general systems issues are described, the state of systems research is given, and open research questions are posed.Mechanical Engineerin
Multi-Axis Planning System (MAPS) for Hybrid Laser Metal Deposition Processes
This paper summarizes the research and development of a Multi-Axis Planning System (MAPS) for hybrid laser metal deposition processes. The project goal is to enable the current direct metal deposition systems to fully control and utilize multi-axis capability to make complex parts. MAPS allows fully automated process planning for multi-axis layered manufacturing to control direct metal deposition machines for automated fabrication. Such a capability will lead to dramatic reductions in lead time and manufacturing costs for high-value, low-volume components with high performance material. The overall approach, slicing algorithm, machine simulation for planning validation, and the planning results will be presented
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Direct Slicing of STEP Based NURBS Models for Solid Freeform Fabrication
Direct slicing of CAD models to generate process planning instructions for solid freeform
fabrication may overcome inherent disadvantages of using STL format in terms of the process
accuracy, ease of file management, and incorporation of multiple materials. This paper will
present the results of our development of a direct slicing algorithm for layered freeform
fabrication. The direct slicing algorithm was based on a neutral, international standard (ISO
10303) STEP-formatted NURBS geometric representation and is intended to be independent of
any commercial CAD software. The following aspects of the development effort will be
presented: 1) Determination of optimal build direction based upon STEP-based NURBS models;
2) Adaptive subdivision of NURBS data for geometric refinement; and 3) Ray-casting slice
generation into sets of raster patterns. Feasibility studies applying the direct slicing algorithm to
example models and the generation of fabrication planning instructions involving multi-material
structures will also be presented.Mechanical Engineerin
Multi axis slicing for rapid prototyping
With multi-axis capability, direct laser deposition process can produce a metal part without the usage of support structures. In order to fully utilize such a capability, a slicing method for multi-axis metal deposition process is discussed. Using the geometry information of adjacent layers, the slicing direction and layer thickness can be changed as needed. A hierarchy structure is designed to manage the topological information which is used to determine the slicing sequence. The parallel slicing process is studied to build hollow type structure. With such a character, the hole like feature can be deposited directly to save the required machining operation and material cost, which improves the efficiency of the metal deposition process. Combined with direct 3D layer deposition technique, the multi-axis slicing method is implemented --Abstract, page iii
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