scholarly journals 3D DIGITIZING TECHNOLOGY IN PRODUCT REVERSE DESIGN

Author(s):  
Qingjin Peng ◽  
Hector Sanchez

The reverse design develops new products based on the improvement of existing products. The shape recovery of three-dimensional (3D) objects is the basis of the product reverse design. 3D digitization technology is an important tool for the 3D shape recovery. This paper analyses the current 3D data acquisition technology. The accuracy and performance of the 3D laser scanner is evaluated. A cost-effective approach is proposed to recover 3D shape of objects using a structured-light technique. Details of the proposed method are described. Application examples are presented. The accuracy is evaluated using a coordinate measuring machine.

2015 ◽  
Vol 20 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Mahtab Nouri ◽  
Arash Farzan ◽  
Ali Reza Akbarzadeh Baghban ◽  
Reza Massudi

OBJECTIVE: The aim of the present study was to assess the diagnostic value of a laser scanner developed to determine the coordinates of clinical bracket points and to compare with the results of a coordinate measuring machine (CMM). METHODS: This diagnostic experimental study was conducted on maxillary and mandibular orthodontic study casts of 18 adults with normal Class I occlusion. First, the coordinates of the bracket points were measured on all casts by a CMM. Then, the three-dimensional coordinates (X, Y, Z) of the bracket points were measured on the same casts by a 3D laser scanner designed at Shahid Beheshti University, Tehran, Iran. The validity and reliability of each system were assessed by means of intraclass correlation coefficient (ICC) and Dahlberg's formula. RESULTS: The difference between the mean dimension and the actual value for the CMM was 0.0066 mm. (95% CI: 69.98340, 69.99140). The mean difference for the laser scanner was 0.107 ± 0.133 mm (95% CI: -0.002, 0.24). In each method, differences were not significant. The ICC comparing the two methods was 0.998 for the X coordinate, and 0.996 for the Y coordinate; the mean difference for coordinates recorded in the entire arch and for each tooth was 0.616 mm. CONCLUSION: The accuracy of clinical bracket point coordinates measured by the laser scanner was equal to that of CMM. The mean difference in measurements was within the range of operator errors.


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.


2013 ◽  
Vol 315 ◽  
pp. 63-67 ◽  
Author(s):  
Muhammad Fahad ◽  
Neil Hopkinson

Rapid prototyping refers to building three dimensional parts in a tool-less, layer by layer manner using the CAD geometry of the part. Additive Manufacturing (AM) is the name given to the application of rapid prototyping technologies to produce functional, end use items. Since AM is relatively new area of manufacturing processes, various processes are being developed and analyzed for their performance (mainly speed and accuracy). This paper deals with the design of a new benchmark part to analyze the flatness of parts produced on High Speed Sintering (HSS) which is a novel Additive Manufacturing process and is currently being developed at Loughborough University. The designed benchmark part comprised of various features such as cubes, holes, cylinders, spheres and cones on a flat base and the build material used for these parts was nylon 12 powder. Flatness and curvature of the base of these parts were measured using a coordinate measuring machine (CMM) and the results are discussed in relation to the operating parameters of the process.The result show changes in the flatness of part with the depth of part in the bed which is attributed to the thermal gradient within the build envelope during build.


2021 ◽  
Vol 186 (Supplement_1) ◽  
pp. 659-664
Author(s):  
David A Boone ◽  
Sarah R Chang

ABSTRACT Introduction This research has resulted in a system of sensors and software for effectively adjusting prosthetic alignment with digital numeric control. We called this suite of technologies the Prosthesis Smart Alignment Tool (ProSAT) system. Materials and Methods The ProSAT system has three components: a prosthesis-embedded sensor, an alignment tool, and an Internet-connected alignment expert system application that utilizes machine learning to analyze prosthetic alignment. All components communicate via Bluetooth. Together, they provide for numerically controlled prosthesis alignment adjustment. The ProSAT components help diagnose and guide the correction of very subtle, difficult-to-see imbalances in dynamic gait. The sensor has been cross-validated against kinetic measurement in a gait laboratory, and bench testing was performed to validate the performance of the tool while adjusting a prosthetic socket based on machine learning analyses from the software application. Results The three-dimensional alignment of the prosthetic socket was measured pre- and postadjustment from two fiducial points marked on the anterior surface of the prosthetic socket. A coordinate measuring machine was used to derive an alignment angular offset from vertical for both conditions: pre- and postalignment conditions. Of interest is the difference in the angles between conditions. The ProSAT tool is only controlling the relative change made to the alignment, not an absolute position or orientation. Target alignments were calculated by the machine learning algorithm in the ProSAT software, based on input of kinetic data samples representing the precondition and where a real prosthetic misalignment condition was known a priori. Detected misalignments were converted by the software to a corrective adjustment in the prosthesis alignment being tested. We demonstrated that a user could successfully and quickly achieve target postalignment change within an average of 0.1°. Conclusions The accuracy of a prototype ProSAT system has been validated for controlled alignment changes by a prosthetist. Refinement of the ergonomic form and technical function of the hardware and clinical usability of the mobile software application are currently being completed with benchtop experiments in advance of further human subject testing of alignment efficiency, accuracy, and user experience.


Author(s):  
C. J. Rolls ◽  
W. ElMaraghy ◽  
H. ElMaraghy

Abstract Reverse engineering (RE), may be defined as the process of generating computer aided design models (CAD) from existing or prototype parts. The process has been used for many years in industry. It has markedly increased in implementation in the past few years, primarily due to the introduction of rapid part digitization technologies. Current industrial applications include CAD model construction from artisan geometry, such as in automotive body styling, the generation of custom fits to human surfaces, and quality control. This paper summarizes the principles of operation behind many commercially available part digitization technologies, and discusses techniques involved in part digitization using a coordinate measuring machine (CMM) and laser scanner. An overall error characterization of the laser scanning digitization process is presented for a particular scanner. This is followed by a discussion of the merits and considerations involved in generating combined data sets with characteristics indicative of the design intent of specific part features. Issues in facilitating the assembly, or registration, of the different types of data into a single point set are discussed.


Author(s):  
W. H. ElMaraghy ◽  
Z. Wu ◽  
H. A. ElMaraghy

Abstract This paper focuses on the development of a procedure and algorithms for the systematic comparison of geometric variations of measured features with their specified geometric tolerances. To automate the inspection of mechanical parts, it is necessary to analyze the measurement data captured by coordinate measuring machines (CMM) in order to detect out-of-tolerance conditions. A procedure for determining the geometric tolerances from the measured three dimensional coordinates on the surface of a cylindrical feature is presented. This procedure follows the definitions of the geometric tolerances used in the current Standards, and is capable of determining the value of each geometric tolerance from the composite 3-D data. The developed algorithms adopt the minimum tolerance zone criterion. Nonlinear numerical optimization techniques are used to fit the data to the minimum tolerance zone. Two test cases are given in the paper which demonstrate the successful determination of geometric tolerances from given simulated data.


2020 ◽  
Vol 12 (23) ◽  
pp. 9943
Author(s):  
Jong-Won Lee ◽  
Deuk-Woo Kim ◽  
Seung-Eon Lee ◽  
Jae-Weon Jeong

This paper summarizes the recent post-occupancy evaluation (POE) method studies and latest literature reviews. According to the research trends, data visualization of an occupant’s feedback is an important perspective and surveys through POE methods have provided a quick and cost-effective approach for gathering and analyzing an occupant’s feedback. Therefore, the objective of this study is to establish a web-based building occupant survey system that incorporates new approaches based on a geographic information system (GIS) tool and open-source spatial information. This paper reports the following to provide the detailed system framework: (1) development requirements from literature reviews; (2) integration of collected data and 3D (three dimensional) spatial information; (3) system processes and user-friendly functions; and (4) pilot test and data visualization. The difference between the proposed platform and existing online survey systems is that in the former the survey responses are linked to the 3D spatial information of the buildings on a map. Thus, the results provide more intuitive insights for building managers and occupants to identify specific performance issues related to the building.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Hussam Mutwalli ◽  
Michael Braian ◽  
Deyar Mahmood ◽  
Christel Larsson

Aim. To measure the trueness and precision under repeatable conditions for different intraoral scanners (IOSs) when scanning fully edentulous arch with multiple implants. Materials and Methods. Three IOSs and one industrial scanner were used to scan one edentulous master cast containing five implant scan bodies and three spheres. The cast was scanned thirty times with each scanner device. All scans were analyzed in the inspect software, and three-dimensional locations of the implants and the interarch distance between the spheres were measured. The values were compared to measurements made with one coordinate measuring machine (true value). One-way ANOVA was used to calculate the differences between IOSs and in comparison with the true value. Results. Significant differences were found between all IOSs. For the implant measurements, Trios 3 had the lowest trueness (≤114 μm), followed by Trios 3 mono (≤63 μm) and Itero element (≤−41 μm). Trios had the lowest precision (≤135 μm), followed by Itero element (≤101 μm) and Trios 3 mono (≤100 μm). With regard to the interarch distance measurements, Trios 3 had the lowest trueness (≤68 μm), followed by Trios 3 mono (≤45 μm) and Itero element (≤40 μm). Trios 3 had the lowest precision (≤206 μm), followed by Itero element (≤124 μm) and Trios 3 mono (≤111 μm). Conclusion. The results from this in vitro study suggest that precision is low for the tested IOS devices when scanning fully edentulous arches with multiple implants.


Geophysics ◽  
1989 ◽  
Vol 54 (7) ◽  
pp. 815-823
Author(s):  
F. M. Peterson ◽  
W. C. Reynish

Three‐dimensional (3-D) seismic prospecting is generally perceived as a very expensive tool that is not suitable for use by other than major oil companies or for the solution of conventional exploration geophysics problems. We illustrate how 3-D techniques were used to provide a very cost‐effective solution to a specific exploration project. A basic geologic and historical seismic outline establishes the economic and environmental framework for the survey. Drilling results and comparisons with conventional data illustrate the effectiveness of the 3-D approach. This survey was carried out during February of 1982 in the Black Creek basin of northwestern Alberta. Prolific and abundant Devonian Keg River pinnacle reefs with reserves in the 0.2 to 100 million barrel recoverable categories provide the exploration target. A prospective area of approximately [Formula: see text] was covered with a 165 ft subsurface grid of 1200 percent CDP data. Field data were acquired with a conventional 96-trace dynamite crew using a rolling, crossed‐array technique. Data processing was carried out with a flexible, conventional seismic processing package, including wavelet deconvolution, surface‐consistent statics, 3-D migration, and geologic slice displays. Total cost of the survey was $50,000 Canadian per sq mi. This paper demonstrates the interpretive power of 3-D surveys.


2010 ◽  
Vol 102-104 ◽  
pp. 189-193
Author(s):  
Ling Yun Jiang ◽  
Zhi Biao Wang

The process of creating a CAD model from an object is mainly made up of two steps: the data collection through digital measurement and the construction of parameterized and revisable model. This paper discusses the measuring process and technical problems of the Coordinate Measuring Machine (CMM) and non-contact sensor. Through comparative analysis, we determine the application scope of those approaches in measuring different dimensions of the same objects considering the time efficiency and tolerance requirement. This paper divide the objects into two categories: freeform feature objects and regular feature objects. As for the freeform feature objects, people could fit wrap-around B-spline surfaces to construct the model. Regular feature objects for mass produce contain machined surfaces which should be precisely measured and modeled. The model of regular feature object should be constructed by three-dimensional modeling software, so that it is parametric and revisable for changing and improving the original design. Sizes and position of important surfaces of the model are acquired from CMM, and those of non-important features are fitted though point cloud processing. Some profile can’t be measured directly from CMM but should be precise, so this paper proposed two methods to construct profile line and analyze error by comparing it with point cloud.


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