scholarly journals Spherical Maps: Their Construction, Properties, and Approximation

1994 ◽  
Vol 116 (2) ◽  
pp. 357-363 ◽  
Author(s):  
J. G. Gan ◽  
T. C. Woo ◽  
K. Tang
Keyword(s):  
Unit Sphere ◽  
Design For Manufacturing ◽  
Numerical Control ◽  
Scene Analysis ◽  
Convex Hulls ◽  
Coordinate Measurement ◽  
Surface Intersection ◽  
Component Design ◽  
Gaussian Maps ◽  
Spherical Maps

The Gaussian map and its allied visibility map on a unit sphere find wide applications for orientating the workpiece for machining by numerical control machines and for probing by coordinate measurement machines. They also provide useful aids in computerized scene analysis, computation of surface-surface intersection, component design for manufacturing and fabrication procedures. Spherical convex hulls and spherical circles are two geometric constructs used to approximate the Gaussian maps and the visibility maps. The duality and the complementarity of these spherical maps are examined so as to derive efficient algorithms.

Generation and Enforcement of Process-Driven Manufacturability Constraints: A Survey of Methods and Perspectives for Product Design

2021 ◽  
pp. 1-33
Author(s):  
Albert Patterson ◽  
Yong Hoon Lee ◽  
James T. Allison
Keyword(s):  
General Solution ◽  
Design For Manufacturing ◽  
Top Down ◽  
Specific Process ◽  
Micro Scale ◽  
Component Design ◽  
Macro Scale ◽  
Simple Mass ◽  
Common Problems ◽  
Scale Design

Abstract Design-for-manufacturing (DFM) concepts have traditionally focused on design simplification; this is highly effective for relatively simple, mass-produced products, but tends to be too restrictive for more complex designs. Effort in recent decades has focused on creating methods for generating and imposing specific, process-derived technical manufacturability constraints for some common problems. This paper presents an overview of the problem and its design implications, a discussion of the nature of the manufacturability constraints, and a survey of the existing approaches and methods for generating/enforcing the minimally-restrictive manufacturability constraints within several design domains. Five major design perspectives or viewpoints were included in the study, including the system design (top-down), product/component design (bottom-up), the manufacturing process-dominant case (product/component design under a specific process), the part-redesign perspective, and sustainability perspective. Manufacturability constraints within four design levels or scales were explored as well, ranging from macro-scale to sub-micro-scale design. Very little previous work was found in many areas, but it is clear from the existing literature that the problem and a general solution to it are very important to explore further in future DFM efforts.

Research of Fused Deposition Modeling Process Oriented Component Design

2015 ◽  
Vol 1095 ◽  
pp. 828-832 ◽  
Author(s):  
Zi Fan Huang ◽  
Yue Long Ma ◽  
Jia Hai Wei ◽  
Ai Qiong Pan ◽  
Jun Liu
Keyword(s):  
Rapid Prototyping ◽  
Fused Deposition Modeling ◽  
Reference Value ◽  
Design For Manufacturing ◽  
Fused Deposition ◽  
Component Design ◽  
Forming Precision ◽  
Deposition Modeling ◽  
Process Oriented ◽  
Low Efficiency

In the process of Fused Deposition molding (Fused Deposition Modeling, FDM), because the 3 d design is disconnected with manufacturing (or process), and prototype and precision is influenced by many factors, there are many disadvantages such as much design rework, difficult processing, low efficiency and high cost. Based on the concept of Design for Manufacturing ((Design for Manufacturing, DFM), this paper analyzes several factors that influence the forming accuracy, and puts forward the corresponding solutions to improve rapid prototyping manufacture parts strength and forming precision, combined with the actual rapid prototyping processing. It has certain reference value in the study of parameter selection and structure improvement of FDM process oriented component design.

scholarly journals Permittivity of 3D-Printed Nylon Substrates with Different Infill Patterns and Densities for Design of Microwave Components

Designs ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 39
Author(s):  
Hanxiong Hu ◽  
Swapnil Sinha ◽  
Nicholas Meisel ◽  
Sven G. Bilén
Keyword(s):  
Additive Manufacturing ◽  
Relative Permittivity ◽  
Printed Circuit Boards ◽  
Numerical Control ◽  
Circuit Boards ◽  
Rectangular Patch ◽  
Component Design ◽  
Rectangular Pattern ◽  
Microwave Components ◽  
Value Changes

Printed circuit boards, chemical etching, and computer numerical control milling currently dominate industrial processes for manufacturing microwave components. However, these manufacturing methods do not provide the flexibility for customization possible with additive manufacturing. Additive manufacturing (AM) has the potential to fabricate microwave components for desired frequency ranges with less effort in prototyping and fabrication. Relative permittivity (εr) of materials is a critical parameter in microwave component design, yet the value changes during the AM process. This article investigates how relative permittivity for nylon substrates, created with AM, changes with different infill densities and infill patterns. The measurement method and procedure can be used to design AM microwave components like antennas or dielectric-filled waveguides with desired characteristics. The two-microstrip-line method was used and improved for the accurate and convenient measurement of the relative permittivity of AM nylon substrates. Several nylon substrates with different infill patterns, including rectangular, hexagonal, triangular, and solid, were fabricated with AM to demonstrate how the relative permittivity value changes as the infill density increases. A linear relationship between the infill density of the rectangular pattern and the substrate permittivity was found. The permittivity data were applied to the design of a rectangular patch antenna for use in the 2.5-GHz WiMAX band. The fabricated antenna with AM, which was tested using a vector network analyzer, showed good agreement with simulation results. The method and procedure of permittivity measurements are specially designed to be applied in the design of microwave components with AM dielectric substrates.

Computational Geometry on the Sphere With Application to Automated Machining

1992 ◽  
Vol 114 (2) ◽  
pp. 288-295 ◽  
Author(s):  
Lin-Lin Chen ◽  
T. C. Woo
Keyword(s):  
Computational Geometry ◽  
Convex Hull ◽  
Unit Sphere ◽  
Degrees Of Freedom ◽  
Cutting Tools ◽  
Numerical Control ◽  
Geometric Algorithms ◽  
New Class

Based on observations made on the geometry of the cutting tools and the degrees of freedom in 3-, 4-, 5-axis numerical control machines, a new class of geometric algorithms is induced on the unit sphere. Spherical algorithms are useful for determining the type of tool, its path, workpiece fixturing, and the type of machine. Basic to these algorithms are four that are presented here: detection of convexity on the sphere, computation for spherically convex hull, determination of the spherical convexity of a union, and the intersection of hemispheres. These four algorithms are related by duality and the sharing of partial results.

Computational Geometry on the Sphere With Application to Automated Machining

1990 ◽  
Author(s):  
Lin-Lin Chen ◽  
Tony C. Woo
Keyword(s):  
Computational Geometry ◽  
Convex Hull ◽  
Unit Sphere ◽  
Degrees Of Freedom ◽  
Cutting Tools ◽  
Numerical Control ◽  
Geometric Algorithms ◽  
New Class

Abstract Based on observations made on the geometry of the cutting tools and the degrees of freedom in 3-, 4-, 5-axis numerical control machines, a new class of geometric algorithms is induced — on the unit Sphere. Spherical algorithms are useful for determining the type of tool, its path, workpiece fixturing, and the type of machine. Basic to these algorithms are four that are presented here: detection of convexity on the sphere, computation for spherically convex hull, determination of the spherical convexity of a union and the intersection of hemispheres. These four algorithms are related by duality and the sharing of partial results.

scholarly journals Near net shape manufacturing of metal: A review of approaches and their evolutions

2017 ◽  
Vol 232 (4) ◽  
pp. 650-669 ◽  
Author(s):  
Daniele Marini ◽  
David Cunningham ◽  
Jonathan R Corney
Keyword(s):  
Computer Aided Design ◽  
Material Selection ◽  
Numerical Control ◽  
Raw Material ◽  
Production Volume ◽  
Component Design ◽  
Shaping Process ◽  
Near Net Shape ◽  
Control Technologies ◽  
Aided Design

In the last 30 years, the concept of manufacturability has been applied to many different processes in numerous industries. This has resulted in the emergence of several different “Design for Manufacturing” methodologies which have in common the aim of reducing productions costs through the application of general manufacturing rules. Near net shape technologies have expanded these concepts, targeting mainly primary shaping process, such as casting and forging. The desired outcomes of manufacturability analysis for near net shape processes are cost and lead/time reduction through minimization of process steps (in particular cutting and finishing operations) and raw material saving. Product quality improvement, variability reduction and component design functionality enhancement are also achievable through near net shape optimization. Process parameters, product design and material selection are the changing variables in a manufacturing chain that interact in complex, non-linear ways. Consequently, modeling and simulation play important roles in the investigation of alternative approaches. However, defining the manufacturing capability of different processes is also a “moving target” because the various near net shape technologies are constantly improving and evolving so there is challenge in accurately reflecting their requirements and capabilities. In the last decade, for example, computer-aided design, computer numerical control technologies and innovation in materials have impacted enormously on the development of near net shape technologies. This article reviews the different methods reported for near net shape manufacturability assessment and examines how they can make an impact on cost, quality and process variability in the context of a specific production volume. The discussion identifies a lack of structured approaches, poor connection with process optimization methodologies and a lack of empirical models as gaps in the reported approaches.

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