A Reverse Compensation Framework for Shape Deformation in Additive Manufacturing

2016 ◽  
Author(s):  
Kai Xu ◽  
Tsz-Ho Kwok ◽  
Yong Chen
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Shape Deformation ◽  
Cad Model ◽  
Complex Deformation ◽  
Physical Measurements ◽  
Building Process ◽  
Aided Design ◽  
Thermal Cooling ◽  
And Control

Shape deformation is an important issue in additive manufacturing (AM) processes such as the projection-based Stereolithography. Volumetric shrinkage and thermal cooling during the photopolymerization process combined with other factors such as the layer-constrained building process lead to complex deformation that is difficult to predict and control. In this paper, a general reverse compensation method and related computation framework are presented to reduce the shape deformation of AM fabricated parts. During the reverse compensation process, the shape deformation is calculated based on physical measurements of shape deformation. A novel method for identifying the correspondence between the deformed shape and the given nominal computer-aided design (CAD) model is presented based on added markers. Accordingly, a new CAD model based on the shape deformation and related compensation is computed. The intelligently revised CAD model by going through the same building process can result in a fabricated part that is close to the nominal CAD model. Two test cases have been designed to demonstrate the effectiveness of the presented method and the related computation framework. The shape deformation in terms of L2- and L∞-norm based on measuring the geometric errors is reduced by 40–60%.

scholarly journals A Reverse Compensation Framework for Shape Deformation Control in Additive Manufacturing

2017 ◽  
Vol 17 (2) ◽  
Author(s):  
Kai Xu ◽  
Tsz-Ho Kwok ◽  
Zhengcai Zhao ◽  
Yong Chen
Keyword(s):  
Additive Manufacturing ◽  
Shape Deformation ◽  
Layer By Layer ◽  
Computational Framework ◽  
Deformation Control ◽  
Nominal Model ◽  
Physical Measurements ◽  
Building Process ◽  
Compensation Approach ◽  
Thermal Cooling

Shape deformation is a well-known problem in additive manufacturing (AM). For example, in the stereolithography (SL) process, some of the factors that lead to part deformation including volumetric shrinkage, thermal cooling, added supporting structures, and the layer-by-layer building process. Variant sources of deformation and their interactions make it difficult to predict and control the shape deformation to achieve high accuracy that is comparable to numerically controlled machining. In this paper, a computational framework based on a general reverse compensation approach is presented to reduce the shape deformation in AM processes. In the reverse compensation process, the shape deformation is first calculated by physical measurements. A novel method to capture the physical deformation by finding the optimal correspondence between the deformed shape and the given nominal model is presented. The amount of compensation is determined by a compensation profile that is established based on nominal and offset models. The compensated digital model can be rebuilt using the same building process for a part with significantly less part deformation than the built part related to the nominal model. Two test cases have been performed to demonstrate the effectiveness of the presented computational framework. There is a 40–60% improvement in terms of L2- and L∞-norm measurements on geometric errors.

Laser Additive Manufacturing

3D Printing ◽  
2017 ◽  
pp. 154-171 ◽  
Author(s):  
Rasheedat M. Mahamood ◽  
Esther T. Akinlabi
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Computer Aided Design ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Cad Model ◽  
Laser Additive Manufacturing ◽  
Computer Aided ◽  
Manufacturing Technologies ◽  
Aided Design

Laser additive manufacturing is an advanced manufacturing process for making prototypes as well as functional parts directly from the three dimensional (3D) Computer-Aided Design (CAD) model of the part and the parts are built up adding materials layer after layer, until the part is competed. Of all the additive manufacturing process, laser additive manufacturing is more favoured because of the advantages that laser offers. Laser is characterized by collimated linear beam that can be accurately controlled. This chapter brings to light, the various laser additive manufacturing technologies such as: - selective laser sintering and melting, stereolithography and laser metal deposition. Each of these laser additive manufacturing technologies are described with their merits and demerits as well as their areas of applications. Properties of some of the parts produced through these processes are also reviewed in this chapter.

scholarly journals 3D PRINTING….. A PARADIGM SHIFT IN ENDODONTICS

2020 ◽  
pp. 1-3
Author(s):  
Abhishek Bansal ◽  
Navneet kukreja ◽  
Shivangi Trivedi ◽  
Jayant Verma ◽  
Jyoti Bansal ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Paradigm Shift ◽  
Computer Aided Design ◽  
Cad Model ◽  
Layer By Layer ◽  
3 Dimensional ◽  
Successive Addition ◽  
Computer Aided ◽  
Aided Design

Abstract: The process of 3 Dimensional (3D) printing is used to create a 3D object with the help of a computer aided design (CAD) model, by successive addition of material layer by layer thus it is also known as additive manufacturing. During 1990’s, the technique of 3D printing was only applied for the manufacture of aesthetic or functional prototypes and was suitably named as rapid prototyping. The following descriptive review presents with an overview about contemporary 3D printing technologies and their use in various specialties of dentistry and largely focusing on the applications of this technology in the endodontics.

Laser Additive Manufacturing

2016 ◽  
pp. 1-23 ◽  
Author(s):  
Rasheedat Modupe Mahamood ◽  
Esther Titilayo Akinlabi
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Computer Aided Design ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Cad Model ◽  
Laser Additive Manufacturing ◽  
Computer Aided ◽  
Manufacturing Technologies ◽  
Aided Design

Laser additive manufacturing is an advanced manufacturing process for making prototypes as well as functional parts directly from the three dimensional (3D) Computer-Aided Design (CAD) model of the part and the parts are built up adding materials layer after layer, until the part is competed. Of all the additive manufacturing process, laser additive manufacturing is more favoured because of the advantages that laser offers. Laser is characterized by collimated linear beam that can be accurately controlled. This chapter brings to light, the various laser additive manufacturing technologies such as: - selective laser sintering and melting, stereolithography and laser metal deposition. Each of these laser additive manufacturing technologies are described with their merits and demerits as well as their areas of applications. Properties of some of the parts produced through these processes are also reviewed in this chapter.

Bitmap generation from computer-aided design for potential layer-quality evaluation in electron beam additive manufacturing

2020 ◽  
Vol 26 (5) ◽  
pp. 941-950
Author(s):  
Hay Wong
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Quality Assessment ◽  
Process Monitoring ◽  
Computer Aided Design ◽  
Reference Image ◽  
Cad Model ◽  
Content Type ◽  
Computer Aided ◽  
Aided Design

Purpose Electron beam additive manufacturing (EBAM) is a popular additive manufacturing (AM) technique used by many industrial sectors. In EBAM process monitoring, data analysis is focused on information extraction directly from the raw data collected in-process, i.e. thermal/optical/electronic images, and the comparison between the collected data and the computed tomography/microscopy images generated after the EBAM process. This paper aims to postulate that a stack of bitmaps could be generated from the computer-aided design (CAD) at a range of Z heights and user-defined region of interest during file preparation of the EBAM process, and serve as a reference image set. Design/methodology/approach Comparison between that and the workpiece images collected during the EBAM process could then be used for quality assessment purposes. In spite of the extensive literature on CAD slicing and contour generation for AM process preparation, the method of bitmap generation from the CAD model at different field of views (FOVs) has not been disseminated in detail. This article presents a piece of custom CAD-bitmap generation software and an experiment demonstrating the application of the software alongside an electronic imaging system prototype. Findings Results show that the software is capable of generating binary bitmaps with user-defined Z heights, image dimensions and image FOVs from the CAD model; and can generate reference bitmaps to work with workpiece electronic images for potential pixel-to-pixel image comparison. Originality/value It is envisaged that this CAD-bitmap image generation ability opens up new opportunities in quality assessment for the in-process monitoring of the EBAM process.

scholarly journals Automatized Evaluation of Students’ CAD Models

2021 ◽  
Vol 11 (4) ◽  
pp. 145
Author(s):  
Nenad Bojcetic ◽  
Filip Valjak ◽  
Dragan Zezelj ◽  
Tomislav Martinec
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Computer Application ◽  
Test Cases ◽  
Cad Model ◽  
Computer Solution ◽  
3D Cad ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

The article describes an attempt to address the automatized evaluation of student three-dimensional (3D) computer-aided design (CAD) models. The driving idea was conceptualized under the restraints of the COVID pandemic, driven by the problem of evaluating a large number of student 3D CAD models. The described computer solution can be implemented using any CAD computer application that supports customization. Test cases showed that the proposed solution was valid and could be used to evaluate many students’ 3D CAD models. The computer solution can also be used to help students to better understand how to create a 3D CAD model, thereby complying with the requirements of particular teachers.

scholarly journals Optimization of the Bi-Axial Tracking System for a Photovoltaic Platform

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 535
Author(s):  
Cătălin Alexandru
Keyword(s):  
Computer Aided Design ◽  
Tracking System ◽  
Control Device ◽  
Computer Applications ◽  
Optimization Study ◽  
Solar Tracker ◽  
Diurnal Movement ◽  
Multi Body ◽  
Aided Design ◽  
And Control

The article deals with the optimization of the azimuthal tracking mechanism for a photovoltaic (PV) platform, which uses linear actuators as actuation elements for both movements (diurnal and elevation). In the case of diurnal movement, where the platform’s angular field of orientation is large, a mechanism with a relatively simple structure is used for amplifying the actuator’s stroke and avoiding the risk of the system locking itself (by limiting the values of the transmission angle). The optimization study targets the mechanical device, the control device, and the bi-axial tracking program (embodied by the laws of motion in time for the platform’s diurnal and elevation angles) with the purpose of obtaining a high input of solar radiation, with a minimal energy consumption to achieve tracking. The study is carried out by using a virtual prototyping platform, which includes Computer Aided Design (CAD), Multi-Body Systems (MBS), and Design for Control (DFC) computer applications. The mechanical and control devices of the solar tracker are integrated and tested in mechatronic concept. The simulations’ results, which were performed for a set of representative days throughout the year, prove the effectiveness of the proposed design.

scholarly journals Prototype of Augmented Reality Technology for Orthodontic Bracket Positioning: An In Vivo Study

2021 ◽  
Vol 11 (5) ◽  
pp. 2315
Author(s):  
Yu-Cheng Lo ◽  
Guan-An Chen ◽  
Yin Chun Liu ◽  
Yuan-Hou Chen ◽  
Jui-Ting Hsu ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Navigation System ◽  
Computer Aided Design ◽  
Control Group ◽  
Orthodontic Bracket ◽  
Bracket Position ◽  
Aided Design ◽  
Clinical Error ◽  
And Control

To improve the accuracy of bracket placement in vivo, a protocol and device were introduced, which consisted of operative procedures for accurate control, a computer-aided design, and an augmented reality–assisted bracket navigation system. The present study evaluated the accuracy of this protocol. Methods: Thirty-one incisor teeth were tested from four participators. The teeth were bonded by novice and expert orthodontists. Compared with the control group by Boone gauge and the experiment group by augmented reality-assisted bracket navigation system, our study used for brackets measurement. To evaluate the accuracy, deviations of positions for bracket placement were measured. Results: The augmented reality-assisted bracket navigation system and control group were used in the same 31 cases. The priority of bonding brackets between control group or experiment group was decided by tossing coins, and then the teeth were debonded and the other technique was used. The medium vertical (incisogingival) position deviation in the control and AR groups by the novice orthodontist was 0.90 ± 0.06 mm and 0.51 ± 0.24 mm, respectively (p < 0.05), and by the expert orthodontist was 0.40 ± 0.29 mm and 0.29 ± 0.08 mm, respectively (p < 0.05). No significant changes in the horizontal position deviation were noted regardless of the orthodontist experience or use of the augmented reality–assisted bracket navigation system. Conclusion: The augmented reality–assisted bracket navigation system increased the accuracy rate by the expert orthodontist in the incisogingival direction and helped the novice orthodontist guide the bracket position within an acceptable clinical error of approximately 0.5 mm.

scholarly journals Digital Workflow to Fabricate Complete Dentures for Edentulous Patients Using a Reversing and Superimposing Technique

2021 ◽  
Vol 11 (13) ◽  
pp. 5786
Author(s):  
Hwa-Jung Lee ◽  
Jeongho Jeon ◽  
Hong Seok Moon ◽  
Kyung Chul Oh
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Digital Data ◽  
Complete Dentures ◽  
Intraoral Scanner ◽  
Digital Workflow ◽  
Denture Base ◽  
Scan Data ◽  
Edentulous Patients ◽  
Aided Design

This technical procedure demonstrates a 4-step completely digital workflow for the fabrication of complete dentures in edentulous patients. The digital scan data of the edentulous arches were obtained using an intraoral scanner, followed by the fabrication of modeless trial denture bases using additive manufacturing. Using the trial denture base and a wax rim assembly, the interarch relationship was recorded. This record was digitized using an intraoral scanner and reversed for each maxillary and mandibular section individually. The digital scan data directly obtained using the intraoral scanner were superimposed over the reversed data, establishing a proper interarch relationship. The artificial teeth were arranged virtually and try-in dentures were additively manufactured. Subsequently, the gingival and tooth sections were additively manufactured individually and characterized. Thus, fabrication of digital complete dentures can be accomplished using digital data characteristics. The workflow includes data acquisition using an intraoral scanner, data processing using reverse engineering and computer-aided design software programs, and additive manufacturing.

Sign in / Sign up

Export Citation Format

Share Document