Some Geometric Techniques to Reduce Build Time in LOM

2001 ◽  
Author(s):  
Pang King Wah ◽  
Ajay Joneja
Keyword(s):  
Layered Manufacturing ◽  
Manufacturing Technology ◽  
Rectangular Grid ◽  
Geometric Properties ◽  
Traditional Technique ◽  
Laminated Object Manufacturing ◽  
Build Time ◽  
Waste Removal ◽  
Geometric Techniques

Abstract We propose a new CAPP system for the layered manufacturing technology of LOM (laminated object manufacturing). The traditional technique of building wastes much effort and time in generation of rectangular grid patterns to the exterior of the model to facilitate waste removal. In the proposed approach, several geometric properties of the model are exploited to dramatically reduce the waste removal grids. This in turn leads to reduced build-time, with no effect on the build quality. An integrated CAPP system incorporating these ideas has been developed, and an example part is presented to show how the system performs.

Multi-Direction Slicing for Layered Manufacturing

2000 ◽  
Author(s):  
Prabhjot Singh ◽  
Debasish Dutta
Keyword(s):  
Surface Quality ◽  
Layered Manufacturing ◽  
Support Structure ◽  
Surface Accuracy ◽  
Build Time ◽  
Limited Surface

Abstract Parts made by Layered Manufacturing (LM) have a limited surface accuracy and their build time is often long due to the deposition of sacrificial support structure. However, LM machines with an ability to deposit along multiple directions can improve upon the surface quality and reduce the support volume. In this paper we consider multi-directional slicing, present algorithms and implemented examples.

Offset Slices for Multidirection Layered Deposition

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Prabhjot Singh ◽  
Debasish Dutta
Keyword(s):  
Layered Manufacturing ◽  
Thin Layers ◽  
Post Processing ◽  
Build Time ◽  
Overhang Angle ◽  
Task Framework

Layered Manufacturing (LM) techniques build a part by adding thin layers of material. In this process, overhangs need to be supported by sacrificial supports, resulting in an increase in the build time, wastage of material, and costly post-processing. Metal-based LM machines with the capability to deposit material along multiple directions resolve most of the above problems. Importantly, these machines can deposit nonplanar slices. In this paper, we study such slices and present a task framework for their use with multidirectional layered deposition machines. The aim of the analysis is to identify part subvolumes that can be built using nonplanar slices for a process-dependent overhang angle. Solution methodologies for 2D, extruded parts, and general 3D parts are presented. Algorithms and illustrative example parts are included.

Tolerance-Based Layer Setup Optimization for Layered Manufacturing

2010 ◽  
Author(s):  
Jack Szu-Shen Chen ◽  
Hsi-Yung Steve Feng
Keyword(s):  
Layer Thickness ◽  
Maximum Error ◽  
Layered Manufacturing ◽  
Design Model ◽  
Maximum Efficiency ◽  
Original Design ◽  
Allowable Deviation ◽  
Number Of Layers ◽  
Build Time ◽  
Model Geometry

This paper introduces a new tolerance-based method to generate the optimum layer setup required to build layered manufacturing (LM) end-user parts for maximized efficiency. To achieve this, the deviation between the final polished LM part geometry and the original design model are formulated and controlled. Maximized layer thicknesses are then realized through optimization of each layer position with respect to the design and final geometry and maximization of the allowable deviation for each layer, which consequently leads to minimization of the build time. Current LM layer setup methods do not take into account of the final part during layer setup generation, rendering layer thickness selection to operator-deemed-best. Without the ability to predict the final geometry and to optimize the layer setup accordingly, layer thickness selection is often overly conservative, causing more layers than necessary to be used. Since the LM build time increases exponentially with an increase in the number of layers, efficiency is greatly reduced with conservative layer setup. To achieve maximum efficiency, this paper proposes a new method based on error compensation and minimization to solve for the optimum layer setup necessary to allow the resulting final physical part to reliably approximate the design model geometry according to a user specified tolerance limit. Case studies have been performed in order to validate that the proposed method is able to minimize the number of layers for constructing an LM part while controlling the maximum error for tolerance conformance.

Pre-Processing of Heterogeneous Objects for Layered Manufacturing

2001 ◽  
Author(s):  
Ki-Hoon Shin ◽  
Debasish Dutta
Keyword(s):  
Tool Path ◽  
New Technology ◽  
Three Dimensional ◽  
Layered Manufacturing ◽  
Pattern Generation ◽  
Geometric Features ◽  
Adaptive Slicing ◽  
Heterogeneous Objects ◽  
Build Time ◽  
Material Information

Abstract Layered manufacturing (LM) is emerging as a new technology that enables fabrication of three dimensional heterogeneous objects (such as Multi-materials and Functionally Gradient Materials). The steps for fabricating heterogeneous objects include model representation and material process planning. This paper introduces a method for processing the material information. It includes pre-processing (discretization), orientation (build direction selection), and adaptive slicing of heterogeneous objects. The discretization process converts all material information inside a heterogeneous object to material features like geometric features, thus it makes it possible to determine build direction by estimating build time based on geometric features and material features. It also allows adaptive slicing of heterogeneous objects to minimize surface finish and material resolution error. In addition, tool path planning can be simplified to fill pattern generation. Examples are shown.

Multi-Direction Slicing for Layered Manufacturing

2001 ◽  
Vol 1 (2) ◽  
pp. 129-142 ◽  
Author(s):  
Prabhjot Singh ◽  
Debasish Dutta
Keyword(s):  
Surface Quality ◽  
Layered Manufacturing ◽  
Support Structure ◽  
Surface Accuracy ◽  
Build Time ◽  
Key Issues ◽  
Limited Surface ◽  
Task Framework

Parts made by Layered Manufacturing (LM) have a limited surface accuracy and their build time is often long due to the deposition of sacrificial support structure. However, LM machines with an ability to deposit along multiple directions can improve upon the surface quality and reduce the support volume. In this paper we analyze the problem of multi-direction slicing. This analysis addresses the questions: How much of a part should be made along a particular direction and why. The strategy used in multi-direction slicing is to progressively decompose the part into sub-volumes, each of which can be completely built along a certain direction. Key issues are identified and a task framework for multidirection slicing is proposed. Algorithms and implemented examples are presented.

Process-Planning for Layered Manufacturing of Heterogeneous Objects Using Direct Metal Deposition

2002 ◽  
Vol 2 (4) ◽  
pp. 330-344 ◽  
Author(s):  
Ki-Hoon Shin ◽  
Debasish Dutta
Keyword(s):  
Process Planning ◽  
Tool Path ◽  
Three Dimensional ◽  
Layered Manufacturing ◽  
Pattern Generation ◽  
Adaptive Slicing ◽  
Heterogeneous Objects ◽  
Build Time ◽  
Material Information ◽  
Discretization Process

Layered manufacturing (LM) is emerging as a new technology that enables the fabrication of three-dimensional heterogeneous objects such as multimaterials and functionally gradient materials (FGMs). The necessary steps for LM fabrication of heterogeneous objects include representation and process planning of material information inside an object. This paper introduces a new processing planning method that takes into account the processing of material information. The detailed tasks are pre-processing (discretization), orientation (build direction selection), and adaptive slicing of heterogeneous objects. In particular, this paper focuses on the discretization process that converts all of the material information inside a heterogeneous object into material features like geometric features. It is thus possible to choose an optimal build direction among various preselected ones by approximately estimating build time. This is because total build time depends on the complexity of features. This discretization process also allows adaptive slicing of heterogeneous objects to minimize surface finish and material composition error. In addition, tool path planning can be simplified into fill pattern generation. Examples are shown to illustrate the overall procedure.

Offset Slices for Layered Manufacturing

2002 ◽  
Author(s):  
Prabhjot Singh ◽  
Debasish Dutta
Keyword(s):  
Layered Manufacturing ◽  
Thin Layers ◽  
Post Processing ◽  
Build Time ◽  
Solution Methodology ◽  
Dimensional Domain ◽  
Task Framework

Layered Manufacturing (LM) techniques build a part by adding thin layers of material. In this process overhangs need to be supported by sacrificial supports, resulting in an increase in the build time, wastage of material and requiring costly post-processing. Metal based LM machines with the capability to deposit material along multiple directions resolve most of the above problems. These machines have the capability to deposit non-planar slices. In this paper we study such slices and present a task framework for their use with multi-directional LM machines. A solution methodology is presented for the 2 dimensional domain which can be extended to 3 dimensions.

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