scholarly journals EFFICIENT 3D DATA COMPRESSION THROUGH PARAMETERIZATION OF FREE-FORM SURFACE PATCHES

2010 ◽  
Keyword(s):  
Data Compression ◽  
Free Form ◽  
Surface Patches ◽  
3D Data ◽  
Free Form Surface

Generation of Regularly Aligned Curved Surface Patches on Free-Form Surface for Patch Division Milling

2012 ◽  
Vol 523-524 ◽  
pp. 54-57
Author(s):  
Kai Xu ◽  
Hiroyuki Sasahara
Keyword(s):  
Tool Path ◽  
End Milling ◽  
Added Value ◽  
Curved Surface ◽  
Surface Patch ◽  
Free Form ◽  
Feed Speed ◽  
Machined Surface ◽  
Surface Patches ◽  
Free Form Surface

This study describes a new machining strategy to make regularly aligned cutter marks on free-form surface efficiently for increasing the added value of industrial product. While the free-form surface is divided into many small patch segments employing curved surface patch division milling technique which can substitute for the conventional method, thus avoiding the influence of the change in the curvature. And the patch segments will be machined by a spiral tool path respectively, so that regularly aligned cutter marks can be successfully formed on the curved surface patches by controlling cross-feed, feed speed per tooth, number of teeth and the length of the tool path. Comparing the machined surface and the simulation result, the cutter marks agree with it. If the surface is machined only by the ball end milling with a machining center, this method will be a very effective tool for the machinery industry.

Discrete Curvature Approximations for the Segmentation of Polyhedral Surfaces

2001 ◽  
Author(s):  
D. Lesage ◽  
J.-C. Léon ◽  
P. Véron
Keyword(s):  
Free Form ◽  
Data Input ◽  
Discrete Curvature ◽  
Surface Patches ◽  
Reduction Techniques ◽  
Segmentation Process ◽  
Discrete Curvatures ◽  
Edge Swapping ◽  
Free Form Surface ◽  
Two Stages

Abstract The segmentation of digitized data to decompose a free form surface into patches is one of the key processes used to perform the reverse engineering of an object. To this end, discrete curvature approximations are introduced that form the basis of a segmentation process which lead to a decomposition of digitized data into areas that will help the construction of surface patches. The approach presented relies on the use of a polyhedral representation of an object built from the digitized data input. Then, it is shown how noise reduction techniques, edge swapping techniques and adapted remeshing schemes can participate to different preparation phases which provide a geometry that highlights useful characteristics for the segmentation process. The segmentation process is performed with various approximations of discrete curvatures evaluated on the polyhedrons issued by the preparation phases. The segmentation process proposed involves two stages: the identification of characteristic polylines and the identification of polyhedral regions. Discrete curvature criteria are adapted to each stage and concepts of invariant are introduced to generate criteria, which are constant over equivalent meshes. An outline of the segmentation procedure is provided together with examples of results for free form objects.

A Complementary Sensor Approach to Reverse Engineering

2000 ◽  
Vol 123 (1) ◽  
pp. 74-82 ◽  
Author(s):  
C. Bradley ◽  
V. Chan
Keyword(s):  
Reverse Engineering ◽  
Boundary Data ◽  
Surface Patch ◽  
Free Form ◽  
Data Set ◽  
B Spline ◽  
Cloud Data ◽  
Surface Patches ◽  
Free Form Surface ◽  
Touch Probe

A complementary sensor technique for reverse engineering objects that are represented by a three-dimensional (3D) cloud data set is reported. The research focuses on objects whose surface form is manifest as a set of distinct free-form surface patches, each of which is enclosed by a boundary. The method incorporates three stages: (1) laser scanner-based digitization of all the free-form surface patches, (2) touch probe-based digitization of the surface patch boundaries, and (3) modeling of both data sets to create a complete B-spline curve and surface representation of the object. The patch boundary data, defined by the touch probe, is employed to segment the free-form surface data into the constituent patches. Furthermore, the boundary data is incorporated within a B-spline surface fitting process to constrain the boundaries. The two sensors functionally complement each other; the range sensor provides the required dense resolution of 3D points on the free-form surfaces whereas the touch probe accurately defines the patch boundaries. The method is ideal for objects comprised of both functional engineering features, e.g. bearing holes or precise mounting locators, and aesthetic features, such as hand grips or part covers. The touch probe is also ideal for digitizing boundaries where occlusion prevents the use of an optical digitizer. The laser-based sensor has an accuracy specification of 50 microns (over a 40-mm depth of field) whereas the touch probe is accurate to 4 microns over a 25-mm measurement length. An example part is modeled that has multiple free-form patches (defining the part’s outer cover) that require a large cloud data set for complete coverage. The corresponding patch boundaries accurately define the location of critical part mounting locations that require the touch probe’s precision.

scholarly journals Innovative Methodology of On-Line Point Cloud Data Compression for Free-Form Surface Scanning Measurement

2018 ◽  
Vol 8 (12) ◽  
pp. 2556 ◽  
Author(s):  
Yan Li ◽  
Yuyong Ma ◽  
Ye Tao ◽  
Zhengmeng Hou
Keyword(s):  
Data Compression ◽  
Point Cloud ◽  
Free Form ◽  
Point Cloud Data ◽  
Cloud Data ◽  
Innovative Methodology ◽  
Dense Point ◽  
On Line ◽  
Free Form Surface ◽  
Line Point

In order to obtain a highly accurate profile of a measured three-dimensional (3D) free-form surface, a scanning measuring device has to produce extremely dense point cloud data with a great sampling rate. Bottlenecks are created owing to inefficiencies in manipulating, storing and transferring these data, and parametric modelling from them is quite time-consuming work. In order to effectively compress the dense point cloud data obtained from a 3D free-form surface during the real-time scanning measuring process, this paper presents an innovative methodology of an on-line point cloud data compression algorithm for 3D free-form surface scanning measurement. It has the ability to identify and eliminate data redundancy caused by geometric feature similarity between adjacent scanning layers. At first, the new algorithm adopts the bi-Akima method to compress the initial point cloud data; next, the data redundancy existing in the compressed point cloud is further identified and eliminated; then, we can get the final compressed point cloud data. Finally, the experiment is conducted, and the results demonstrate that the proposed algorithm is capable of obtaining high-quality data compression results with higher data compression ratios than other existing on-line point cloud data compression/reduction methods.

A Golay3 sparse aperture optical system of primary mirror with free-form surface

2021 ◽  
Vol 28 (1) ◽  
pp. 113-118
Author(s):  
Bin Chen ◽  
Quanying Wu ◽  
Junliu Fan
Keyword(s):  
Optical System ◽  
Free Form ◽  
Primary Mirror ◽  
Sparse Aperture ◽  
Free Form Surface

Tool Path Generation for Five-Axis Controlled Machining of Free-Form Surface Using Barrel Tool: Control of Contact Point on Cutting Edge

2020 ◽  
Author(s):  
Tomonobu Suzuki ◽  
Koichi Morishige
Keyword(s):  
Tool Path ◽  
Contact Point ◽  
Cutting Edge ◽  
Free Form ◽  
End Mill ◽  
Ball End Mill ◽  
Surface Machining ◽  
Free Form Surface ◽  
The Cost ◽  
Five Axis

Abstract This study aimed to improve the efficiency of free-form surface machining by using a five-axis controlled machine tool and a barrel tool. The barrel tool has cutting edges, with curvature smaller than the radius, increasing the pick feed width compared with a conventional ball end mill of the same tool radius. As a result, the machining efficiency can be improved; however, the cost of the barrel tool is high and difficult to reground. In this study, a method to obtain the cutting points that make the cusp height below the target value is proposed. Moreover, a method to improve the tool life by continuously and uniformly changing the contact point on the cutting edge is proposed. The usefulness of the developed method is confirmed through machining simulations.

Application of Convex Hull for Tool Interference Avoidance in 5-Axis CNC Machining

1996 ◽  
Author(s):  
Yuan-Shin Lee ◽  
Tien-Chien Chang
Keyword(s):  
Convex Hull ◽  
Tool Path ◽  
Correction Method ◽  
Nc Machining ◽  
Cnc Machining ◽  
Free Form ◽  
Interference Avoidance ◽  
Tool Interference ◽  
Free Form Surface ◽  
Free Form Surfaces

Abstract In this paper, a methodology of applying convex hull property in solving the tool interference problem is presented for 5-axis NC machining of free-form surfaces. Instead of exhausted point-by-point checking for possible tool interference, a quick checking can be done by using the convex hull constructed from the control polygon of free-form surface modeling. Global tool interference in 5-axis NC machining is detected using the convex hull of the free-form surface. A correction method for removing tool interference has also been developed to generate correct tool path for 5-axis NC machining. The inter-surface tool interference can be avoided by using the developed technique.

Creation and Manipulation of Complex Displacement Features During the Conceptual Phase of Design

1996 ◽  
Author(s):  
P. A. van Elsas ◽  
J. S. M. Vergeest
Keyword(s):  
Boundary Conditions ◽  
Surface Feature ◽  
Free Form ◽  
Shape Design ◽  
Surface Model ◽  
Test Results ◽  
Base Surface ◽  
Feature Design ◽  
Data Explosion ◽  
Free Form Surface

Abstract Surface feature design is not well supported by contemporary free form surface modelers. For one type of surface feature, the displacement feature, it is shown that intuitive controls can be defined for its design. A method is described that, given a surface model, allows a designer to create and manipulate displacement features. The method uses numerically stable calculations, and feedback can be obtained within tenths of a second, allowing the designer to employ the different controls with unprecedented flexibility. The algorithm does not use refinement techniques, that generally lead to data explosion. The transition geometry, connecting a base surface to a displaced region, is found explicitly. Cross-boundary smoothness is dealt with automatically, leaving the designer to concentrate on the design, instead of having to deal with mathematical boundary conditions. Early test results indicate that interactive support is possible, thus making this a useful tool for conceptual shape design.

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