Displaying publications 1 - 20 of 66 in total

  1. Siswanto WA, Anggono AD, Omar B, Jusoff K
    ScientificWorldJournal, 2014;2014:301271.
    PMID: 25165738 DOI: 10.1155/2014/301271
    The aim of this work is to improve the accuracy of cold stamping product by accommodating springback. This is a numerical approach to improve the accuracy of springback analysis and die compensation process combining the displacement adjustment (DA) method and the spring forward (SF) algorithm. This alternate hybrid method (HM) is conducted by firstly employing DA method followed by the SF method instead of either DA or SF method individually. The springback shape and the target part are used to optimize the die surfaces compensating springback. The hybrid method (HM) algorithm has been coded in Fortran and tested in two- and three-dimensional models. By implementing the HM, the springback error can be decreased and the dimensional deviation falls in the predefined tolerance range.
    Matched MeSH terms: Computer-Aided Design*
  2. Lim WC, Kanagaraj G, Ponnambalam SG
    ScientificWorldJournal, 2014;2014:264518.
    PMID: 24707198 DOI: 10.1155/2014/264518
    Optimization of drill path can lead to significant reduction in machining time which directly improves productivity of manufacturing systems. In a batch production of a large number of items to be drilled such as printed circuit boards (PCB), the travel time of the drilling device is a significant portion of the overall manufacturing process. To increase PCB manufacturing productivity and to reduce production costs, a good option is to minimize the drill path route using an optimization algorithm. This paper reports a combinatorial cuckoo search algorithm for solving drill path optimization problem. The performance of the proposed algorithm is tested and verified with three case studies from the literature. The computational experience conducted in this research indicates that the proposed algorithm is capable of efficiently finding the optimal path for PCB holes drilling process.
    Matched MeSH terms: Computer-Aided Design/instrumentation*
  3. Abdullah SJ, Shaikh Mohammed J
    Assist Technol, 2018;30(4):165-175.
    PMID: 28346064 DOI: 10.1080/10400435.2017.1293193
    Independent mobility is vital to individuals of all ages, and wheelchairs have proven to be great personal mobility devices. The tasks of opening and navigating through a door are trivial for healthy people, while the same tasks could be difficult for some wheelchair users. A wide range of intelligent wheelchair controllers and systems, robotic arms, or manipulator attachments integrated with wheelchairs have been developed for various applications, including manipulating door knobs. Unfortunately, the intelligent wheelchairs and robotic attachments are not widely available as commercial products. Therefore, the current manuscript presents the modeling and simulation of a novel but simple technology in the form of a passive wheelchair accessory (straight, arm-like with a single wheel, and arc-shaped with multiple wheels) for pushing doors open from a wheelchair. From the simulations using different wheel shapes and sizes, it was found that the arc-shaped accessory could push open the doors faster and with almost half the required force as compared to the arm-like accessory. Also, smaller spherical wheels were found to be best in terms of reaction forces on the wheels. Prototypes based on the arc-shaped accessory design will be manufactured and evaluated for pushing doors open and dodging or gliding other obstacles.
    Matched MeSH terms: Computer-Aided Design*
  4. Kul E, Abdulrahim R, Bayındır F, Matori KA, Gül P
    Dent Med Probl, 2021 5 14;58(2):187-191.
    PMID: 33982454 DOI: 10.17219/dmp/126745
    BACKGROUND: If a temporary restoration is in the esthetic area and needs to be worn for a long time, the color stability of temporary materials becomes an important factor.

    OBJECTIVES: The aim of this in vitro study was to evaluate the long-term effects of various staining solutions on the color stability of different temporary materials produced with the computer-aided design and computer-aided manufacturing (CAD/CAM) technology.

    MATERIAL AND METHODS: In the study, the following materials were used: VITA CAD-Temp® (group 1); Ceramill® Temp (group 2); and Telio® CAD (group 3). Forty disk-shaped specimens (10 mm in diameter, 2 mm in thickness) of each material (N = 120) were produced with a CAD/CAM system. Staining solutions - of tea (A), of coffee (B) and cola (C) - and distilled water (D, control) were used, and color was evaluated before and after storing the samples in the solutions. Measurements were taken with a spectrophotometer and the color parameters (L*, a*, b*, and ΔE) were calculated according to the Commission internationale de l'éclairage system (CIELab). The results were evaluated with the two-way analysis of variance (ANOVA) and Tukey's tests (α = 0.05).

    RESULTS: Clinically perceivable (ΔE00 > 0.8) and statistically significant (p < 0.001) color differences were detected in all specimens. The highest ΔE00 value was found in the Ceramill Temp specimens. In addition, the highest ΔE00 values were noted for the specimens stored in cola and the coffee solution for all groups. The lowest ΔE00 value was observed for the groups stored in the tea solution.

    CONCLUSIONS: Clinically perceivable color changes were observed in all the specimens kept in the solutions. Color changes were greater for cola and coffee as compared to tea.

    Matched MeSH terms: Computer-Aided Design*
  5. Farook TH, Jamayet NB, Abdullah JY, Asif JA, Rajion ZA, Alam MK
    Comput Biol Med, 2020 03;118:103646.
    PMID: 32174323 DOI: 10.1016/j.compbiomed.2020.103646
    OBJECTIVE: To design and compare the outcome of commercial (CS) and open source (OS) software-based 3D prosthetic templates for rehabilitation of maxillofacial defects using a low powered personal computer setup.

    METHOD: Medical image data for five types of defects were selected, segmented, converted and decimated to 3D polygon models on a personal computer. The models were transferred to a computer aided design (CAD) software which aided in designing the prosthesis according to the virtual models. Two templates were designed for each defect, one by an OS (free) system and one by CS. The parameters for analyses were the virtual volume, Dice similarity coefficient (DSC) and Hausdorff's distance (HD) and were executed by the OS point cloud comparison tool.

    RESULT: There was no significant difference (p > 0.05) between CS and OS when comparing the volume of the template outputs. While HD was within 0.05-4.33 mm, evaluation of the percentage similarity and spatial overlap following the DSC showed an average similarity of 67.7% between the two groups. The highest similarity was with orbito-facial prostheses (88.5%) and the lowest with facial plate prosthetics (28.7%).

    CONCLUSION: Although CS and OS pipelines are capable of producing templates which are aesthetically and volumetrically similar, there are slight comparative discrepancies in the landmark position and spatial overlap. This is dependent on the software, associated commands and experienced decision-making. CAD-based templates can be planned on current personal computers following appropriate decimation.

    Matched MeSH terms: Computer-Aided Design*
  6. Ab-Ghani Z, Jaafar W, Foo SF, Ariffin Z, Mohamad D
    J Conserv Dent, 2015 Sep-Oct;18(5):355-9.
    PMID: 26430296 DOI: 10.4103/0972-0707.164028
    To evaluate the shear bond strength between the dentin substrate and computer-aided design and computer-aided manufacturing feldspathic ceramic and nano resin ceramics blocks cemented with resin cement.
    Matched MeSH terms: Computer-Aided Design
  7. Nejat P, Calautit JK, Abd Majid MZ, Hughes BR, Zeynali I, Jomehzadeh F
    Data Brief, 2016 Dec;9:448-452.
    PMID: 27709121
    The data presented in this article were the basis for the study reported in the research articles entitled "Evaluation of a two-sided windcatcher integrated with wing wall (as a new design) and comparison with a conventional windcatcher" (P. Nejat, J.K. Calautit, M.Z.A. Majid, B.R. Hughes, I. Zeynali, F. Jomehzadeh, 2016) [1] which presents the effect of wing wall on the air flow distribution under using the windcatchers as a natural ventilation equipment. Here, we detail the wind tunnel testing and numerical set-up used for obtaining the data on ventilation rates and indoor airflow distribution inside a test room with a two-sided windcatcher and wing wall. Three models were integrated with wing wall angled at 30°, 45° and 60° and another windcatcher was a conventional two-sided device. The computer-aided design (CAD) three-dimensional geometries which were produced using Solid Edge modeler are also included in the data article.
    Matched MeSH terms: Computer-Aided Design
  8. Mohd Faiz Nasruddin, Theocharospoulos, Antonios, Ray, Noel, Burke, Francis M.
    Fitting accuracy of dental prostheses is essential for clinical success. An ideal marginal and internal fit will minimize plaque accumulation, gingival irritation, cement dissolution and micro leakage as well as enhancing the mechanical behaviour of a fixed partial denture (FPD) (1). Unfortunately, there is disagreement about acceptable marginal and internal fit discrepancies of FPD’s (2) from 75-200μm. There are two main manufacturing routes of CAD/CAM FPD’s: the subtractive and the additive route. The subtractive route is a top-down approach which involves milling the desired article out of a block of the material of choice using a series of burs. This route is currently the most common CAD/CAM technique for the fabrication of metal alloy FPD’s. The additive route is a bottom-up approach where the desired article is fabricated layer by layer out of the material of choice. Examples include selective laser sintering and selective laser melting for metal alloy FPD’s.
    Matched MeSH terms: Computer-Aided Design
  9. Nik Zarina Nik Mahmood, Noor Hayaty Abu Kasim, Mamat Azuddin, Noor Lide Abu Kassim
    Compendium of Oral Science, 2015;2(1):21-31.
    Objective: To evaluate the effect of type of viscosity and groove on surface detail reproduction of elastomeric impression materials. Methods: Two polyvinylsiloxane and polyether elastomeric impression materials were investigated. An aluminium cylindrical reference block with V- and U-shaped grooves of 1 mm and 2 mm in depth was machined using CAD-CAM system. Impressions of the block were taken to produce 35 master dies. Each die was immersed in distilled water for 5 minutes prior to impression making. Surface topography of the dies and impressions were captured using Alicona Imaging System. Mean difference in depth between the mas-ter dies and corresponding impressions’ grooves were analyzed. Results: Type of viscosities and groove showed significant main effects on surface detail (p < .01), but no significant interaction was observed between the two (p > .01). Express™ putty/light exhibited the lowest mean difference in depth for all grooves. The highest mean difference for U1 (38.3μm ± 21.55), U2 (52.96μm ± 30.39),V1 (45.02μm ± 34.82) and V2 (58.44μm ± 44.19) was obtained from Impregum medium, Aquasil medium, Impregum™ heavy/light and Impregum™ heavy/light groups respectively. Conclusion: Express putty/light-bodied material produced the best surface detail, and U-shaped groove showed superior detail reproduction.
    Matched MeSH terms: Computer-Aided Design
  10. Islam MM, Islam MT, Faruque MR
    ScientificWorldJournal, 2013;2013:378420.
    PMID: 24385878 DOI: 10.1155/2013/378420
    The dual-band operation of a microstrip patch antenna on a Duroid 5870 substrate for Ku- and K-bands is presented. The fabrication of the proposed antenna is performed with slots and a Duroid 5870 dielectric substrate and is excited by a 50 Ω microstrip transmission line. A high-frequency structural simulator (HFSS) is used which is based on the finite element method (FEM) in this research. The measured impedance bandwidth (2 : 1 VSWR) achieved is 1.07 GHz (15.93 GHz-14.86 GHz) on the lower band and 0.94 GHz (20.67-19.73 GHz) on the upper band. A stable omnidirectional radiation pattern is observed in the operating frequency band. The proposed prototype antenna behavior is discussed in terms of the comparisons of the measured and simulated results.
    Matched MeSH terms: Computer-Aided Design*
  11. Chen J, Ahmad R, Suenaga H, Li W, Sasaki K, Swain M, et al.
    PLoS One, 2015;10(7):e0132552.
    PMID: 26161878 DOI: 10.1371/journal.pone.0132552
    With ever-growing aging population and demand for denture treatments, pressure-induced mucosa lesion and residual ridge resorption remain main sources of clinical complications. Conventional denture design and fabrication are challenged for its labor and experience intensity, urgently necessitating an automatic procedure. This study aims to develop a fully automatic procedure enabling shape optimization and additive manufacturing of removable partial dentures (RPD), to maximize the uniformity of contact pressure distribution on the mucosa, thereby reducing associated clinical complications. A 3D heterogeneous finite element (FE) model was constructed from CT scan, and the critical tissue of mucosa was modeled as a hyperelastic material from in vivo clinical data. A contact shape optimization algorithm was developed based on the bi-directional evolutionary structural optimization (BESO) technique. Both initial and optimized dentures were prototyped by 3D printing technology and evaluated with in vitro tests. Through the optimization, the peak contact pressure was reduced by 70%, and the uniformity was improved by 63%. In vitro tests verified the effectiveness of this procedure, and the hydrostatic pressure induced in the mucosa is well below clinical pressure-pain thresholds (PPT), potentially lessening risk of residual ridge resorption. This proposed computational optimization and additive fabrication procedure provides a novel method for fast denture design and adjustment at low cost, with quantitative guidelines and computer aided design and manufacturing (CAD/CAM) for a specific patient. The integration of digitalized modeling, computational optimization, and free-form fabrication enables more efficient clinical adaptation. The customized optimal denture design is expected to minimize pain/discomfort and potentially reduce long-term residual ridge resorption.
    Matched MeSH terms: Computer-Aided Design*
  12. Alkhatib SE, Tarlochan F, Mehboob H, Singh R, Kadirgama K, Harun WSBW
    Artif Organs, 2019 Jul;43(7):E152-E164.
    PMID: 30805945 DOI: 10.1111/aor.13444
    The mismatch between stiffness of the femoral dense stem and host bone causes complications to patients, such as aseptic loosening and bone resorption. Three-dimensional finite-element models of homogeneous porous (HGP) and functionally graded porous (FGP) stems incorporating body-centered cubic (BCC) structures are proposed in this article as an alternative to the dense stems. The relationship between the porosity and strut thickness of the BCC structure was developed to construct the finite-element models. Three levels of porosities (20%, 50%, and 80%) were modeled in HGP and FGP stems. The porosity of the stems was decreased distally according to the sigmoid function (n = 0.1, n = 1 and n = 10) with 3 grading exponents. The results showed that FGP stems transferred 120%-170% higher stresses to the femur (Gruen zone 7) as compared to the solid stem. Conversely, the stresses in HGP and FGP stems were 12%-34% lower than the dense stem. The highest micromotions (105-147 µm) were observed for stems of 80% overall porosity, and the lowest (42-46 µm) was for stems of 20% overall porosity. Finally, FGP stems with a grading exponent of n = 10 resulted in an 11%-28% reduction in micromotions.
    Matched MeSH terms: Computer-Aided Design*
  13. Albatsh FM, Ahmad S, Mekhilef S, Mokhlis H, Hassan MA
    PLoS One, 2015;10(4):e0123802.
    PMID: 25874560 DOI: 10.1371/journal.pone.0123802
    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches.
    Matched MeSH terms: Computer-Aided Design
  14. Abdul Hamid NF, Wan Bakar WZ, Ariffin Z
    Eur J Dent, 2019 Feb;13(1):17-21.
    PMID: 31170751 DOI: 10.1055/s-0039-1688740
    OBJECTIVE: This study was carried out to assess and compare the marginal gap of conventionally used metal onlays and new resin nanoceramic (RNC) (Lava Ultimate block) onlays.

    MATERIALS AND METHODS: This is an in vitro study using two extracted sound human mandibular molars. One tooth was prepared to receive the metal onlays and another one for the RNC onlays which were fabricated using the computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Twelve metals and 12 ceramic onlays were fabricated before they were placed at their respective preparation and examined under the Leica stereomicroscope, M125C (Leica Microsystems, Wetzlar, Germany) for a marginal analysis. The gap width was measured at 10 predefined landmarks which included 3 points on the buccal and lingual surfaces each and 2 points each on the mesial and distal surfaces, respectively.

    STATISTICAL ANALYSIS: Mann-Whitney post hoc test was used for statistical analysis (P ≤ 0.05).

    RESULTS: Overall, the RNC onlays showed significant lower marginal gap with the exception of the landmarks 5 and 6 (on distolingual) and no significant difference at landmark 7 (on midlingual). It was observed that the marginal gap were all within the clinically acceptable limit of 120 μm.

    CONCLUSIONS: Based on the results obtained, it can be concluded that the RNC CAD/CAM onlays are a promising alternative to the metal onlays.

    Matched MeSH terms: Computer-Aided Design
  15. Afiqah Hamzah N, Razak NAA, Sayuti Ab Karim M, Gholizadeh H
    Proc Inst Mech Eng H, 2021 Dec;235(12):1359-1374.
    PMID: 34304625 DOI: 10.1177/09544119211035200
    The development of the CAD/CAM (Computer-aided design and computer-aided manufacturing) system has globally changed the fabrication and delivery of prosthetics and orthotics. Furthermore, since the introduction of CAD/CAM in the 1980s, many successful CAD/CAM system are available in the market today. However, less than 20% of amputees have access to digital fabrication technology and large portion of the amputees are from the developing countries. This review designed to examine selected studies from 1980 to 2019 on CAD/CAM systems in the production of transtibial prosthetic sockets. A review was conducted based on articles gathered from Web of Science, Pubmed and Science Direct. From the findings, 92 articles found related to CAD/CAM-derived transtibial prosthetic socket (TPS). After a further screening of the articles, 20 studies were chosen and only one study was done in a developing country. The results showed an increase interest in CAD/CAM application in Transtibial prosthetic socket (TPS) production for both developed and developing countries, yet the technology has not fully utilised in the developing countries. Factors such as resources, accessibility, knowledge-gap and lack of experienced prosthetists remain the major causes of the lack of CAD/CAM system studies. Large-scale trials are required to employ digital fabrication in the developing regions, consequently advancing the production of high-quality CAD-CAM-derived TPS where most prosthetic and orthotics are needed.
    Matched MeSH terms: Computer-Aided Design
  16. Goo CL, Tan KB
    Case Rep Dent, 2017;2017:9373818.
    PMID: 28396807 DOI: 10.1155/2017/9373818
    This report describes the clinical and technical aspects in the oral rehabilitation of an edentulous patient with knife-edge ridge at the mandibular anterior edentulous region, using implant-retained overdentures. The application of computer-aided design and computer-aided manufacturing (CAD/CAM) in the fabrication of the overdenture framework simplifies the laboratory process of the implant prostheses. The Nobel Procera CAD/CAM System was utilised to produce a lightweight titanium overdenture bar with locator attachments. It is proposed that the digital workflow of CAD/CAM milled implant overdenture bar allows us to avoid numerous technical steps and possibility of casting errors involved in the conventional casting of such bars.
    Matched MeSH terms: Computer-Aided Design
  17. Berhanuddin Muhamad Asyraf, Tong, Wah Lim
    Malaysian Dental Journal, 2016;2016(2):0-0.
    In nowadays world, aesthetic dentistry has becoming a trend with the improvement of dental technology and materials. Composite resin becomes the material of choice as it offers good aesthetics, longevity and allow for minimally intervention approach. There are various ways of composite restorative techniques recommended to make out the best restorative outcome. Direct restorative technique promise acceptable cost, appointment time and color matching but it is a challenge for the clinician especially for extensive cavities. Indirect technique is good for extended cavity and providing less operator error, however, it requires multiple appointments, higher cost and laboratory involvement. Computer-aided design/ computer-aided manufacturing (CAD/CAM) technology might reduce the number of appointments, however, it will cause more financial burden to the patient and the clinician. Therefore, semi-direct technique was introduced, it combines the benefits of direct and indirect technique and this technique can be done without the use of any advanced technology and give out a good treatment outcome.
    Matched MeSH terms: Computer-Aided Design
  18. Lalegani Dezaki M, Mohd Ariffin MKA
    Polymers (Basel), 2020 Nov 26;12(12).
    PMID: 33255897 DOI: 10.3390/polym12122792
    Fused deposition modeling (FDM) is commonly used to print different products with highly complex features. Process parameters for FDM are divided into controllable or uncontrollable parameters. The most critical ones are built orientation, layer thickness, infill pattern, infill density, and nozzle diameter. This study investigates the effects of combined infill patterns in 3D printed products. Five patterns (solid, honeycomb, wiggle, grid, and rectilinear) were combined in samples to analyze their effects on mechanical properties for tensile strength analysis. Polylactic acid (PLA) samples were printed in different build orientations through two directions: flat and on-edge. The limitation was that the software and machine could not combine the infill patterns. Thus, the patterns were designed and assembled in computer aided design (CAD) software. Finite element analysis (FEA) was used to determine the patterns' features and results showed honeycomb and grid have the highest strength while their weights were lighter compared to solid. Moreover, 0° samples in both flat and on-edge direction had the strongest layer adhesion and the best quality. In contrast, perpendicular samples like 60° and 75° showed poor adhesion and were the weakest specimens in both flat and on-edge, respectively. In brief, by increasing the build orientation, the strength decreases in this study.
    Matched MeSH terms: Computer-Aided Design
  19. Nadia Abdul Rani, Faieza Abdul Aziz, Rohidatun M,W.
    Interactive learning is a pedagogical model that encourages students to be part of the lesson instead of passive observers, quietly sitting at a desk taking notes or memorizing information. Students interact with the material, each other and the teacher in an active way. The new emerging technologies that can overcome some of the potential difficulties in this area includes computer graphics, augmented reality, computational dynamics, and virtual worlds. Therefore, the manufacturing industry relies on new design concepts and methods undertake the challenges in integrating technologies to expedite the march towards industrial revolution 4.0.This paper reviews and investigates the current context of the use of interactive learning such as Virtual Reality(VR),Augmented Reality(AR),Computer aided design and manufacturing(CADCAM), computer graphics, computational dynamics and new emerging technologies that effect on students and lectures in learning and teaching environments for Manufacturing Engineering. Interactive learning is part of the factors that could influence the self-learning and regulations environments.
    Matched MeSH terms: Computer-Aided Design
  20. Farook TH, Abdullah JY, Jamayet NB, Alam MK
    J Prosthet Dent, 2021 Feb 15.
    PMID: 33602541 DOI: 10.1016/j.prosdent.2020.07.039
    STATEMENT OF PROBLEM: Computer-aided design (CAD) of maxillofacial prostheses is a hardware-intensive process. The greater the mesh detail is, the more processing power is required from the computer. A reduction in mesh quality has been shown to reduce workload on computers, yet no reference value of reduction is present for intraoral prostheses that can be applied during the design.

    PURPOSE: The purpose of this simulation study was to establish a reference percentage value that can be used to effectively reduce the size and polygons of the 3D mesh without drastically affecting the dimensions of the prosthesis itself.

    MATERIAL AND METHODS: Fifteen different maxillary palatal defects were simulated on a dental cast and scanned to create 3D casts. Digital bulbs were fabricated from the casts. Conventional bulbs for the defects were fabricated, scanned, and compared with the digital bulb to serve as a control. The polygon parameters of digital bulbs were then reduced by different percentages (75%, 50%, 25%, 10%, 5%, and 1% of the original mesh) which created a total of 105 meshes across 7 mesh groups. The reduced mesh files were compared individually with the original design in an open-source point cloud comparison software program. The parameters of comparison used in this study were Hausdorff distance (HD), Dice similarity coefficient (DSC), and volume.

    RESULTS: The reduction in file size was directly proportional to the amount of mesh reduction. There were minute yet insignificant differences in volume (P>.05) across all mesh groups, with significant differences (P

    Matched MeSH terms: Computer-Aided Design
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