Digital Measurement and its Error Analysis for the Machining Free-Form Surface

2014 ◽  
Vol 664 ◽  
pp. 263-267
Author(s):  
Feng Lu ◽  
Ning Li ◽  
Xiao Fei Zhang

To deal with the lack of accurate and efficient inspection methods in complex free-form surfaces, three-dimensional measurement method based on the optical measurement and computer image processing technology was proposed. It adopted laser scanning technology to get point clouds of free-form surface. Used rapid measurement software to inspect precision of point cloud& CAD model. What could be the cause of machining errors was analyzed. 3D deviation inspection of complex surfaces was applied by an artifact. Detected the machining error of an important section, and outputted test report. This research provides a convenient and swift method for the inspection of free-form surface and processing quality control.

Mechanik ◽  
2018 ◽  
Vol 91 (12) ◽  
pp. 1100-1103
Author(s):  
Andrzej Werner

This article presents a method of increasing the accuracy of the production of free-form surfaces. This method is based on the execution of coordinate measurements of the pre-treated object and reconstruction of its nominal geometric model in order to compensate existing machining errors.


NANO ◽  
2019 ◽  
Vol 14 (01) ◽  
pp. 1950006 ◽  
Author(s):  
Xian Jing ◽  
Kaixuan Wang ◽  
Jieqiong Lin ◽  
Peng Liu ◽  
Yudi Kan ◽  
...  

Slicing reference data and adaptive slicing algorithm are the key issues to find out appropriate layer thicknesses of three-dimensional (3D) microstructures with free-form surface in two photon polymerization (TPP). In the present work, an adaptive slicing method (ASM) was proposed to improve the fabricating efficiency of 3D microstructures with free-form surface in TPP microfabrication. In the proposed method, slicing reference data were obtained by intersecting a series of vertical planes with the triangular patch format along characteristic directions. Maximum acceptable chordal height played a role as judging criteria to obtain appropriate layer thicknesses. What’s more, typical 3D microstructures with free-form surfaces were fabricated with uniform slicing method (USM) and the proposed ASM, respectively. The comparison results showed that the proposed method effectively improved fabricating efficiency, guaranteeing an acceptable surface quality at the same time. This work was expected to provide references for improving fabrication efficiency of complex 3D microstructures in TPP.


2011 ◽  
Vol 55-57 ◽  
pp. 1932-1937
Author(s):  
Li Song ◽  
Shu Kun Cao ◽  
Kai Feng Song ◽  
Chang Zhong Wu ◽  
Wei Wei Song

The paper presented the development of free-form surface axis NC machining tool path optimization module. In the UG environment, have three-dimensional solid modeling to the surface, and then have the secondary development of free-form surfaces five-axis machining path optimization module through the UG/Open API and VC++6.0. This can realize NC processing path automatically generation and optimization after the three-dimensional modeling. Introduction


Author(s):  
C Bradley ◽  
G W Vickers ◽  
M Milroy

A software package for the reverse engineering of surface forms commonly found in manufactured objects is presented. An object's surface is digitized using a three-dimensional, laser-based scanner that produces accurate and copious data files. Complex surface forms are reconstructed by interactively segmenting the multiple-surface patches, invoking the appropriate surface modelling routine and transferring the resulting surfaces to a CAD package via a standard IGES entity. Examples of the accuracy of the laser scanner data, and software algorithms for modelling planes, cylinders, cones and spheres, are presented by performing comparisons with results generated by a coordinate measuring machine. The paper concentrates on the novel software process to model the principal quadric forms; however, the program's capabilities do extend to free-form surfaces.


Author(s):  
P.M.B. Torres ◽  
P. J. S. Gonçalves ◽  
J.M.M. Martins

Purpose – The purpose of this paper is to present a robotic motion compensation system, using ultrasound images, to assist orthopedic surgery. The robotic system can compensate for femur movements during bone drilling procedures. Although it may have other applications, the system was thought to be used in hip resurfacing (HR) prosthesis surgery to implant the initial guide tool. The system requires no fiducial markers implanted in the patient, by using only non-invasive ultrasound images. Design/methodology/approach – The femur location in the operating room is obtained by processing ultrasound (USA) and computer tomography (CT) images, obtained, respectively, in the intra-operative and pre-operative scenarios. During surgery, the bone position and orientation is obtained by registration of USA and CT three-dimensional (3D) point clouds, using an optical measurement system and also passive markers attached to the USA probe and to the drill. The system description, image processing, calibration procedures and results with simulated and real experiments are presented and described to illustrate the system in operation. Findings – The robotic system can compensate for femur movements, during bone drilling procedures. In most experiments, the update was always validated, with errors of 2 mm/4°. Originality/value – The navigation system is based entirely on the information extracted from images obtained from CT pre-operatively and USA intra-operatively. Contrary to current surgical systems, it does not use any type of implant in the bone to track the femur movements.


Author(s):  
Yuan-Shin Lee ◽  
Tien-Chien Chang

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.


2011 ◽  
Vol 287-290 ◽  
pp. 2805-2809
Author(s):  
Ming Yu Huang ◽  
Xiu Juan Wu ◽  
Zhong Shi Jia ◽  
Hong Jun Ni ◽  
Jing Jing Lv ◽  
...  

Data acquisition and model reconstruction of free-form surfaces with holes were been studied, based on coordinate measuring machines. First, the structural process of the parts was analyzed, the method of combinate contact measurement with non-contact measurement were used to get point cloud; Then the point cloud were been preprocessed, feature curve extracted and solid modeled; Finally, the restructure model was been quality assessed and accuracy assessed. Using the measurement of combinated contact and non-contact can also meet both the precision requirement of key part and the fast reconstruction requirement of non-critical part, which has great significance on that part to fast and accurate reconstruction.


Author(s):  
Bisheng Yang ◽  
Yuan Liu ◽  
Fuxun Liang ◽  
Zhen Dong

High Accuracy Driving Maps (HADMs) are the core component of Intelligent Drive Assistant Systems (IDAS), which can effectively reduce the traffic accidents due to human error and provide more comfortable driving experiences. Vehicle-based mobile laser scanning (MLS) systems provide an efficient solution to rapidly capture three-dimensional (3D) point clouds of road environments with high flexibility and precision. This paper proposes a novel method to extract road features (e.g., road surfaces, road boundaries, road markings, buildings, guardrails, street lamps, traffic signs, roadside-trees, power lines, vehicles and so on) for HADMs in highway environment. Quantitative evaluations show that the proposed algorithm attains an average precision and recall in terms of 90.6% and 91.2% in extracting road features. Results demonstrate the efficiencies and feasibilities of the proposed method for extraction of road features for HADMs.


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