Self Calibrated and High Accuracy Thermal Control in Cavities

The study of thermal control in different geometry cavities (cylindrical and rectangular), to obtain high accuracy, short and long term stability responses applied to electronic instruments, is presented. Automatic dynamic electrical compensation is achieved by a feedback electronic circuit and low thermal inertia sensors. One sensor element is also employed as an actuator (heat generator) and the other as a reference sensor (resistance of manganine wire). In the rectangular cavity, the transducer (that is sensor and heater) is manufactured directly in the circuit board surface using a CAD/CAM equipment. This architecture allows a high dimensional accuracy of the sensor/actuator with a minimum track thickness, i.e., around 100 μm. In the cylindrical cavity, the transducer is manufactured using a copper wire. For this geometry, low aspect ratios were analyzed. Electronic response equations are derived and coupled to those governing the heat transfer phenomenon in cavities. After several tests, the model is compared to the experimental data. The obtained results seem to confirm the validity of the proposed idea, allowing an accurate temperature control in cavities with a self calibrating feature. At present time, we have obtained for both geometries a precision around of 0.01°C and an accuracy around of 0.1°C.

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Evaluation of dimensional accuracy of dental bridges manufactured with conventional casting technique and CAD/CAM system with Ceramill Sintron blocks using CMM

Journal of Dental Research Dental Clinics Dental Prospects ◽

10.15171/joddd.2018.041 ◽

2018 ◽

Vol 12 (4) ◽

pp. 264-271 ◽

Cited By ~ 2

Author(s):

Alireza Izadi ◽

Fariborz Vafaee ◽

Arash Shishehian ◽

Ghodratollah Roshanaei ◽

Behzad Fathi Afkari

Keyword(s):

Reference Model ◽

Coordinate Measuring Machine ◽

Dimensional Accuracy ◽

Three Dimensions ◽

Casting Technique ◽

Dimensional Changes ◽

Conventional Casting ◽

Cad Cam ◽

Milling Method ◽

Measuring Machine

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.

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A Digital Near Net Shape Manufacturing Propeller with Complex Surface

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.201-203.117 ◽

2011 ◽

Vol 201-203 ◽

pp. 117-120

Author(s):

Zhong Fei Jiao ◽

Shan Yao ◽

Shu Ming Zhao ◽

Feng Zeng ◽

Di Wu

Keyword(s):

Surface Roughness ◽

Rapid Prototyping ◽

Dimensional Accuracy ◽

Casting Process ◽

Complex Surface ◽

High Accuracy ◽

Parametric Modeling ◽

Marine Propeller ◽

3D Cad ◽

Near Net Shape

An integrated digital routine is applied in the near net shape manufacturing of marine propeller. Firstly, the 3D CAD file of propeller is created by parametric modeling. Secondly, the propeller casting process is simulated using CAE software, through which an optimized casting scheme is obtained. Thirdly, fabricates the mold using laser rapid prototyping and cast the metal propeller. Finally, evaluate the casting precision performance. CAD, CAE and CAM are integrated in this process. The dimensional accuracy of the final piece is controlled within 1mm and its surface roughness achieves Ra 6.3μm. The result shows that the pattern-less casting of propeller can be achieved by this method, reducing cost and performing high accuracy.

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Digital Manufacturing of Implant Based Dental Restorations

Volume 1: Advanced Energy Systems; Advanced and Digital Manufacturing; Advanced Materials; Aerospace ◽

10.1115/esda2008-59242 ◽

2008 ◽

Author(s):

Ming C. Leu ◽

Parthiban Delli

Keyword(s):

Investment Casting ◽

Dimensional Accuracy ◽

Digital Manufacturing ◽

Cnc Milling ◽

Dental Restorations ◽

Human Labor ◽

Cad Cam ◽

Cad Models ◽

Direct Digital Manufacturing ◽

Cam Systems

Traditional methods of producing dental bars for overdentures involve tedious and time-consuming operations that demand substantial human labor and demanding skills. Though there exist several CAD/CAM systems that have been developed for various dental restorations like bridges, crowns, etc., there exists no commercial CAD/CAM system at present for design and fabrication of dental restorations for missing multiple teeth. In the research described in the present paper, CAD models of dental bars for implant-retained dental restorations were used as input for three types of fabrication processes: rapid prototyping followed by investment casting, CNC milling, and direct digital manufacturing. Details of material and process combinations and results of comparing these three types of processes, including an analysis on dimensional accuracy, are discussed.

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Creating Attraction for Technical Education Material and its Educational Benefit (Development of Robotic Education Material Characterized by 3D CAD/CAM and Compact Stereo Vision)

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2011.p0665 ◽

2011 ◽

Vol 23 (5) ◽

pp. 665-675 ◽

Cited By ~ 4

Author(s):

Takeshi Morishita ◽

Keyword(s):

Stereo Vision ◽

Education Program ◽

Engineering Students ◽

Technical Education ◽

Vision System ◽

Processing System ◽

Circuit Board ◽

3D Cad ◽

Education Material ◽

Cad Cam

This paper describes an attractive technical education program and material for engineering students that consists of 3D CAD/CAM technology, CAD/CAM circuit board manufacture, an image information processing system, stereo vision technology and control experiments involving a simple and compact robot equipped with a stereo vision system. In addition, this material, which incorporates 3D attraction, can provide an interesting experience in constructing robot mechatronics and programming for students. Results show that this technical education program can have an excellent effect in enabling students to acquire both hardware and software technology and to obtain control experience with actual robots. Finally, these results indicate that this education program is effective with technical students seeking to learn about system technology including robotics and mechatronics technology

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Mechanical Engineering Tools: A Problem-Based, Introductory Design Course at the American University of Beirut

Volume 7: Engineering Education and Professional Development ◽

10.1115/imece2009-10196 ◽

2009 ◽

Author(s):

R. F. Hamade ◽

N. Ghaddar

Keyword(s):

Mechanical Engineering ◽

Printed Circuit Board ◽

Problem Based Learning ◽

Project Planning ◽

Circuit Board ◽

Learning Methods ◽

American University ◽

Team Members ◽

American University Of Beirut ◽

Cad Cam

Given the prevailing trend of ever decreasing number of required credits, this course solves one of the thorny issues which engineering departments encounter while developing curricula: to teach or not to teach ‘tools’. Those ‘tools of the trade’ include some truly ‘enabling technologies’ comprised of such ‘soft tools’ as CAD/CAM, MATLAB, project planning, controls and of ‘hard tools’ such as reverse engineering, assembly, machine shop fabrication processes, and printed circuit board technology. This course, ME Tools, was introduced in order to offer a viable platform which helps introduce the freshman mechanical engineering student to some of these ‘tools’ in a problem-based context. This goal is met via course organization and prevailing practices conducive to ‘active learning’ via activities and structure typically associated with collaborative and cooperative learning methods. ME Tools climaxes in a 5-event contest during which custom electric microcars are put to action in what is known around the American University of Beirut (AUB) campus as the ‘Gee Whiz contest’. Furthermore, and since the course activities revolve around one central theme, designing and racing an electric microcar, the true integral nature of this course is authenticated and revealed via this problem-based learning approach. This is accomplished as a team effort where teamwork experience and communication skills are highly stressed and practiced. The teams are organized so that the student team members are assigned to one of four functions: manager, systems engineer, analyst, and detail designer. The manner by which the students are assigned to one of these functions is done based on the students’ responses to a short (20 questions) questionnaire designed for this purpose. Assessment wise, grading of certain course grade components is mapped to the specific learning outcomes based on the cooperative, collaborative, and problem-based learning methods.

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Solder joint defect classification based on ensemble learning

Soldering & Surface Mount Technology ◽

10.1108/ssmt-08-2016-0016 ◽

2017 ◽

Vol 29 (3) ◽

pp. 164-170 ◽

Cited By ~ 10

Author(s):

Hao Wu

Keyword(s):

Random Forest ◽

Solder Joint ◽

Decision Trees ◽

Printed Circuit Board ◽

Solder Joints ◽

High Accuracy ◽

Ensemble Method ◽

Circuit Board ◽

Content Type

Purpose This paper aims to inspect the defects of solder joints of printed circuit board in real-time production line, simple computing and high accuracy are primary consideration factors for feature extraction and classification algorithm. Design/methodology/approach In this study, the author presents an ensemble method for the classification of solder joint defects. The new method is based on extracting the color and geometry features after solder image acquisition and using decision trees to guarantee the algorithm’s running executive efficiency. To improve algorithm accuracy, the author proposes an ensemble method of random forest which combined several trees for the classification of solder joints. Findings The proposed method has been tested using 280 samples of solder joints, including good and various defect types, for experiments. The results show that the proposed method has a high accuracy. Originality/value The author extracted the color and geometry features and used decision trees to guarantee the algorithm's running executive efficiency. To improve the algorithm accuracy, the author proposes using an ensemble method of random forest which combined several trees for the classification of solder joints. The results show that the proposed method has a high accuracy.

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Dimensional Accuracy Between Three Different Indirect Scanners For CAD/CAM Systems - An In-vitro Study

Al-Azhar Journal of Dental Science ◽

10.21608/ajdsm.2019.108450 ◽

2019 ◽

Vol 22 (3) ◽

pp. 241-246

Keyword(s):

In Vitro Study ◽

Dimensional Accuracy ◽

Vitro Study ◽

Cad Cam ◽

Cam Systems

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PENENTUAN SETTING OPTIMAL MESIN 3D PRINTER BERBASIS FUSED DEPOSITION MODELING MENGGUNAKAN METODE TAGUCHI

AME (Aplikasi Mekanika dan Energi): Jurnal Ilmiah Teknik Mesin ◽

10.32832/ame.v4i2.1538 ◽

2018 ◽

Vol 4 (2) ◽

Author(s):

Anggit Prakasa ◽

Setya Permana Sutisna ◽

Anton Royanto Ahmad

Keyword(s):

Experimental Design ◽

Taguchi Method ◽

Fused Deposition Modeling ◽

Dimensional Accuracy ◽

High Accuracy ◽

3D Printer ◽

Fused Deposition ◽

3D Printers ◽

Optimal Setting ◽

Deposition Modeling

The 3D printers process is applied to create prototype components, but at the last 3D Printers are often applied as last products. So, high accuracy is required in this case. In this research will find the optimal setting of the dimensional accuracy 3D printers based fused deposition modeling. The method used is the Taguchi method, the reason for using this method its efficiency, this is because the Orthogonal Array matrix requires less number of experiments than the classical experimental design. Analysis of Variance is also needed in this method to see the factors that significantly influence the response variable. The results of this study indicate that the factors that significantly influence is printspeed by contributing 53.08%, flowrate contributes 16.4%, and temperature heater block contributes 3.85% and optimal setting is temperature heater block 190º, print speed 60mm/s and flowrate 6.28 mm3/s. (A1, C3 dan D2).

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