Feature Based Fabrication in Layered Manufacturing

1999 ◽  
Vol 123 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Xiaoping Qian ◽  
Debasish Dutta
Keyword(s):  
Surface Quality ◽  
Material Properties ◽  
Layered Manufacturing ◽  
Feature Interaction ◽  
Interaction Volume ◽  
Curvature Effects ◽  
Volume Decomposition ◽  
Build Time ◽  
Feature Based ◽  
Novel Concept

To address the conflicting requirements between holding specified surface quality and decreasing build time in layered manufacturing, we present a feature-based fabrication methodology whereby the curvature effects are localized within each decomposed volume. However, staircase interaction between the boundaries of the decomposed neighboring volumes creates geometric incompatibility for deposition, which further results in undesired material properties. This paper proposes a novel concept, feature interaction volume, to eliminate the staircase interaction. Based on this concept, a feature based volume decomposition algorithm is developed. This algorithm enables each decomposed volume to be fabricated independently and compatibly. Implementation and example results are also presented.

Feature-Based Slicing for Layered Manufacturing

1999 ◽  
Author(s):  
Xiaoping Qian ◽  
Debasish Dutta
Keyword(s):  
Lead Time ◽  
Layered Manufacturing ◽  
Feature Interaction ◽  
Individual Feature ◽  
Design Specification ◽  
High Quality ◽  
Interaction Volume ◽  
Feature Based ◽  
Slicing Method ◽  
Competition Pressure

Abstract Layered manufacturing (LM) has become an indispensable manufacturing technology for product design and development. Competition pressure demands high quality LM part within an even shorter lead time. This requires an efficient fabrication strategy for LM. In contrast to prevalent LM methods whereby each layer is uniformly deposited with same layer thickness, we are exploring a different approach for LM. That is, fabrication strategies are localized to best meet the design specification of each individual feature in the part. Therefore, slicing, deposition path planning, etc., are done separately for each feature volume to get the best quality for that feature volume. Specifically, in this paper, we present a feature-based slicing method, which localizes the slicing for each individual feature volume. We propose the concept of feature interaction volume and describe how the part volume can be decomposed into refined feature volumes and feature interaction volumes. In refined feature volumes, the fabrication strategies are completely independent of the neighboring volumes. Some examples are presented to validate the feature-based slicing method.

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.

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.

scholarly journals Experimental investigation of the machining characteristics in diamond wire sawing of unidirectional CFRP

2021 ◽  
Author(s):  
Lukas Seeholzer ◽  
Stefan Süssmaier ◽  
Fabian Kneubühler ◽  
Konrad Wegener
Keyword(s):  
Surface Quality ◽  
Influencing Factors ◽  
Material Properties ◽  
High Surface ◽  
Workpiece Surface ◽  
High Surface Quality ◽  
High Productivity ◽  
Surface Temperatures ◽  
Process Forces ◽  
The Wire

AbstractEspecially for slicing hard and brittle materials, wire sawing with electroplated diamond wires is widely used since it combines a high surface quality with a minimum kerf loss. Furthermore, it allows a high productivity by machining multiple workpieces simultaneously. During the machining operation, the wire/workpiece interaction and thus the material removal conditions with the resulting workpiece quality are determined by the material properties and the process and tool parameters. However, applied to machining of carbon fibre reinforced polymers (CFRP), the process complexity potentially increases due to the anisotropic material properties, the elastic spring back potential of the material, and the distinct mechanical wear due to the highly abrasive carbon fibres. Therefore, this experimental study analyses different combinations of influencing factors with respect to process forces, workpiece surface temperatures at the wire entrance, and the surface quality in wire sawing unidirectional CFRP material. As main influencing factors, the cutting and feed speeds, the density of diamond grains on the wire, the workpiece thickness, and the fibre orientation of the CFRP material are analysed and discussed. For the tested parameter settings, it is found that while the influence of the grain density is negligible, workpiece thickness, cutting and feed speeds affect the process substantially. In addition, higher process forces and workpiece surface temperatures do not necessarily deteriorate the surface quality.

Geometric Reasoning Based on Graph Grammar Parsing

1994 ◽  
Vol 116 (3) ◽  
pp. 763-769 ◽  
Author(s):  
Z. Fu ◽  
A. de Pennington
Keyword(s):  
Intelligent Design ◽  
Feature Recognition ◽  
Geometric Reasoning ◽  
Geometric Constraints ◽  
Graph Grammar ◽  
Feature Interaction ◽  
Knowledge Based ◽  
Feature Based ◽  
Feature Information ◽  
And Performance

It has been recognized that future intelligent design support environments need to reason about the geometry of products and to evaluate product functionality and performance against given constraints. A first step towards this goal is to provide a more robust information model which directly relates to design functionality or manufacturing characteristics, on which reasoning can be carried out. This has motivated research on feature-based modelling and reasoning. In this paper, an approach is presented to geometric reasoning based on graph grammar parsing. Our approach is presented to geometric reasoning based on graph grammar parsing. Our work combines methodologies from both design by features and feature recognition. A graph grammar is used to represent and manipulate features and geometric constraints. Geometric constraints are used within symbolical definitions of features constraints. Geometric constraints are used within symbolical definitions of features and also to define relative position and orientation of features. The graph grammar parsing is incorporated with knowledge-based inference to derive feature information and propagate constraints. This approach can be used for the transformation of feature information and to deal with feature interaction.

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.

A Computational Design Framework for a Rapid Solid Freeform Fabrication Process

2000 ◽  
Author(s):  
Deepesh Khandelwal ◽  
T. Kesavadas
Keyword(s):  
Solid Freeform Fabrication ◽  
Optimization Technique ◽  
Three Dimensional ◽  
Computational Design ◽  
Freeform Fabrication ◽  
3D Cad ◽  
Build Time ◽  
Cad Models ◽  
Efficient Machine ◽  
Novel Concept

Abstract Solid Freeform Fabrication (SFF) techniques in recent years have shown tremendous promise in reducing the design time of products. This technique enables designers to get three-dimensional physical prototypes from 3D CAD models. Although SFF has gained popularity, the manufacturing time and cost have limited its use to small and medium sized parts. In this paper we have proposed a novel concept for rapidly building SFF parts by inserting prefabricated inserts into the fabricated part. A computational algorithm was developed for determining ideal placement of inserts/cores in the CAD model of the part being prototyped using a heuristic optimization technique called Simulated Annealing. This approach will also allow the designers to build multi-material prototypes using the Rapid Prototyping (RP) technique. By using cheaper pre-fabricates instead of costly photopolymers, the production cost of the SFFs can be reduced. Additionally it will also reduce build time, resulting in efficient machine utilization.

Novel Concept of Experimental Setup for Characterisation of Plastic Yielding of Sheet Metal at Elevated Temperatures

2005 ◽  
Vol 6-8 ◽  
pp. 657-664 ◽  
Author(s):  
Manfred Geiger ◽  
G. van der Heyd ◽  
Marion Merklein ◽  
Wolfgang Hussnätter
Keyword(s):  
Sheet Metal ◽  
Material Properties ◽  
Room Temperature ◽  
Stress Condition ◽  
Elevated Temperatures ◽  
Biaxial Stress ◽  
Experimental Setup ◽  
Special Importance ◽  
Plastic Yielding ◽  
Novel Concept

In times of highest significance of process modelling and numerical simulation characterisation of material properties is of special importance for tools’ and components’ dimensioning. But in general material properties depend on many different influencing variables, e.g. temperature, humidity and many others. Especially in fields of sheet metal forming the mechanical behaviour of components highly differs according to real stress condition. In particular yield loci combine the information of beginning of yielding with a biaxial stress condition, but nevertheless for many materials they have not been determined yet. For all others the existing values are available only at room temperature. In this paper a novel concept of the experimental setup is shown, with which plastic yielding of sheet metal can be examined also at elevated temperatures. In usual biaxial tension tests cruciform specimen are drawn in plane. The new machine-concept, which is presented in this paper, is based on a punch-load moving perpendicular to the sheet. By clamping the specimen restoring forces are induced, which cause in dependence of special developed tool and work piece geometries defined stress conditions. Using an optical measurement system for determination of strains with CCDcameras of very high frame rate allows exact identification of starting plastification by offline analysis. Experiments at elevated temperatures are realised by local heating with a diode laser and a special optical system to reach a homogenous distribution of temperatures in the forming zone. On the one hand these investigations are necessary for many materials to achieve further information on characteristic properties in warm forming, because their data are only known at room temperature. On the other hand some materials, e.g. magnesium wrought alloys, are mostly formed at elevated temperatures (here in the range of 200°C to 250°C), because of its significant higher formability. Thus, material behaviour must be characterised at these temperatures.

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.

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