Computer-aided Design Data Research Articles

Knife-edged crown fabricated by 3-dimensional gel deposition and soft milling

Statement of problemRestorations with knife-edge margins are more prone to margin chipping during the manufacturing process. Three-dimensional gel deposition shows potential for fabricating zirconia restorations with good margin quality, but studies on its performance in fabricating knife-edged crowns are lacking. PurposeThe purpose of this in vitro study was to compare the 3-dimensional trueness, surface morphology, and margin quality of self-glazed zirconia and soft-milled zirconia crowns with knife-edge margins. Material and methodsAn abutment with a knife-edge finish line design was prepared and scanned with a laboratory scanner. Anatomic contour crowns were designed and fabricated by 3-dimensional gel deposition and soft milling (n=5). The crowns were digitalized, and the scan data were superimposed on the computer-aided design (CAD) data for 3-dimensional deviation analysis. Surface morphology and margin quality were characterized with microscopic examination. ResultsThe self-glazed zirconia crowns showed a smooth and glossy appearance. The soft-milled crowns showed traces left by the removal of support bars and numerous micropits of various sizes. In internal areas, no significant difference was found in root mean square values between the 2 groups (P＞.05). For the external surface, self-glazed zirconia showed statistically lower root mean square values than the soft-milled crowns (P＜.05). When observed at ×5 magnification, all the self-glazed zirconia crowns showed smooth edges with no defects, whereas small or large margin defects were found in the soft-milled crowns. When characterized at ×200 magnification, minor margin flaws were observed in the self-glazed zirconia crowns. More and larger margin defects were found in the soft-milled crowns. ConclusionsThree-dimensional gel deposition forms a smoother and more homogeneous surface than soft milling. Knife-edged self-glazed zirconia crowns have good dimensional accuracy and margin quality.

Integration of AM process in design cycle of metallic parts: Application to space components

Identified in the European strategy as a key enabling technology, Additive Manufacturing (AM) has a great potential for industries to reshape, improve and optimize product life cycle, with reduced environmental footprint such as material waste in production. Allowing to meet structural and multi-disciplinary requirements with complex freeform design at a much lower weight than high constrained conventional manufacturing, AM can benefit to numerous space applications. Beside manufacturing process development, software and process control are becoming absolutely necessary to support digitalization of industrial workflow. Dedicated tools such as Computer Aided Design (CAD), Computer Aided Engineering (CAE) and Computer Aided Manufacturing (CAM) were introduced in the digital manufacturing chain; however, their development was driven by standard manufacturing processes. Therefore, appropriate design methods for AM must emerge in a fully integrated end-to-end solution to foster and support the growth and competitiveness of AM. In order to support industrialization of AM, the European Space Agency has selected the Design4AM project, based on a strong partnership between Siemens and Sonaca, for “Development of Design Methods for AM including CAD Design, Optimization, FEM Analysis and Manufacturing features”. On one hand, the project aims at combining within a comprehensive end-to-end process, topology optimization, seamless CAD data flows and predictive process simulation in the Siemens’ NX™ and Simcenter™ environments. On the other hand, the integration of dedicated industrial design workflow within the enhanced Siemens Digital Innovation Platform is validated on a relevant ESA space application provided by Sonaca.

Effect of process parameters on parts quality and process efficiency of fused deposition modeling

Fused Deposition Modeling (FDM) is an additive manufacturing technique for fabricating parts directly from computer-aided design data by melting, extruding, and resolidifying a thermoplastic filament. This paper presents a methodology for optimizing both process efficiency, i.e., time and energy consumption, and part quality, i.e., surface roughness and dimensional accuracy, of Polylactic Acid (PLA) components produced by FDM. In this work, a Design of Experiments (DoE) approach is adopted to quantify the effects of deposition parameters on process efficiency and part quality outputs. Specifically, the investigated input parameters are layer height, fill density, extruder temperature, part orientation, number of shells, print speed and retraction speed. The mathematical models relating the significant process parameters to the output responses are developed and the responses are optimized considering different scenarios. An experimental validation is performed to test the adequacy of such optimizations. These experimental results showed that, according to the context, different parameter settings pursue different goals in terms of part quality and process efficiency. The proposed approach may effectively help designers determine process parameters’ settings to optimize both part quality and process efficiency and can be applied to either prototype or part production.

Predicting Positioning Error and Finding Features for Large Industrial Robots Based on Deep Learning

In this study, we evaluated the motion accuracy of a large industrial robot and its compensation method and constructed an off-line teaching operation based on three-dimensional computer aided design data. In this experiment, we used a laser tracker to measure the coordinates of the end effector of the robot. Simultaneously, the end-effector coordinates, each joint angle, the maximum current of the motors attached to each joint, and rotation speed of each joint were measured. This servo information was converted into image data as visible information. For each robot movement path, an image was created; the horizontal axis represented the movement time of the robot and the vertical axis represented the servo information. A convolutional neural network (CNN), a type of deep learning, was used to predict the positioning error with high accuracy. Subsequently, to identify the features of the positioning error, the image was divided into several analysis areas, one of which was filled with various colors and analyzed by the CNN. If the prediction accuracy of the CNN decreased, then the analysis area would be identified as a feature. Thus, the features of the Y-axis positioning error were observed for teaching each joint angle in the opposite direction just after the start of the motion, overshoot of the rotational joint current, and the change in the swivel joint current.

Evaluation of Ni-Based Flexible Resistance Temperature Detectors Fabricated by Laser Digital Pattering.

Temperature sensors are ubiquitous in every field of engineering application since temperature control is vital in operating, testing and monitoring various equipment systems. Herein, we introduce a facile and rapid laser digital patterning (LDP) process to fabricate low-cost, Ni-based flexible resistance temperature detectors (RTDs). Ni-based RTDs are directly generated on a thin flexible polyimide substrate (thickness: 50 µm) by laser-induced reductive sintering of a solution-processed nonstoichiometric nickel oxide (NiOx) nanoparticle thin film under ambient conditions. The shape of RTDs can be easily adjusted by controlling computer-aided design (CAD) data without using the physical patterning mask while the sensitivity (temperature coefficient of resistance (α) ~ 3.52 × 10−3 °C−1) of the sensors can be maintained regardless of shape and size of the sensor electrodes. The flexible Ni-based RTDs can operate over a wide temperature range up to 200 °C with excellent repeatability. Additionally, the Ni-based RTDs respond quickly to the temperature change and can operate in corrosive environments including water and seawater. Moreover, the Ni-based RTDs show a superior mechanical and electrical stability with a negligible resistance change up to a radius of curvature of 1.75 mm. Finally, a tape-pull test demonstrates the robust adhesion of Ni-based RTDs on the substrate.

ПЕРСПЕКТИВИ РОЗВИТКУ БАЗ ДАНИХ В УМОВАХ ЦИФРОВОЇ ЕКОНОМІКИ

Nowadays each country considers a direction of the digital economy development prioritized. The purpose of the research is to analyze and synthesize the existing prospects of databases development in the digital economy, as well as to identify key technologies and tools that will contribute to this development. Digital technologies are the foundation of a country's prosperity, as they create new opportunities in a rapidly changing world. Today Ukraine's rating on international indices of the global digital competitiveness is unstable. Currently the country is focused on the development of innovations, however, hasn’t used them to improve the economic performance yet. To ensure the operation with databases in modern information systems the database management systems are used. Today there are 378 database management systems in the world. The distinctive feature of the database is that the information within it is necessarily processed by electronic media with a subsequent systematization, which is a subject to certain rules. Designing a database is a complex and time-consuming process. The process of a designing the database means to create a database schema and determine the necessary information integrity constraints. Databases are used as a part of the information system: computer-aided design systems, data banks, information retrieval and expert systems, automated workstations, automated control systems. The process of a proper and timely development of the digital economy can significantly affect the production growth rate, quality of life, level of services. Any process requires special tools, methods and technologies. Regarding tools in the context of the digital economy, such concepts as the Internet of Things, big data, blockchain, neural networks, cloud computing and other tools are generally implied, where the main focus of them is to maximize the digitization of all the information flows for the creation of an information society. It is determined that databases as a powerful component of digital tools allow to combine production with individuality, reduce the development period of innovative ideas till the sale of finished products, provide an opportunity to achieve an effective adaptation to consumer requirements.

Interoperability of CAD models and SysML specifications for the automated checking of design requirements

Currently and in view of technological development, mechatronic systems have become more and more complex. This will undoubtedly influenc the design of products. For this reason, designers do not stop developing new solutions to best ensure customer satisfaction on functional dimensional and geometrical requirements. However, to achieve a finished product satisfying all stakeholders, designers should face a multitud of problems. Among them, the difficulty of data exchange between the different developers contributing to the design process of a finishe product. Several research works have focused on data exchange between Computer Aided Design (CAD) and Computer Aided Engineering applications (CAE) or at the CAD development and manufacturing levels. However, few works study the interoperability between all the produc development levels and the system engineering one. For instance, the lack of continuity between the system-engineering model which has global view on the product, and the CAD model which integrates the parts and assembly CAD data, causes an enormous lost time in th verification and validation process of requirements. In this paper a methodology allowing the interoperability between the system leve specifications and the CAD model of a product being designed is proposed. Based on SysML diagrams, the customer needs and the functiona analysis of the product lead to the definition of the initial structure of the product assembly. The results of this step are used as an input by th CAD designer to detail the architecture of the mechanical assembly. Finally, the product assembly data required for verification and validatio are extracted from the CAD model and then used back to enrich the preliminary SysML model. The system engineer uses the collected data i the SysML model to check and validate the product requirements according to a V model. A pedal of a bicycle was used as an example to illustrat and prove the effectiveness and efficiency of the proposed approach.

Applicability of Formwork Automation Design Software for Aluminum Formwork

In this study, by applying the developed formwork automation design software to three target structures, we reviewed the applicability of the formwork automation design software for the aluminum formwork. To apply the formwork automation design software, we built an aluminum formwork library based on the conversion of two-dimensional (2D) computer-aided design (CAD) data to three-dimensional building information modeling data for all the components of the aluminum formwork. The results of the automated formwork layout on the target structures using the formwork automation design software confirmed that the wall and deck members were laid out by the set algorithm according to the formwork size and direction. However, because of the limited functionality of the software, the level of completion of the formwork layout was found to be lower than that of the manual formwork layout based on 2D CAD data. The currently developed software is based on a simple algorithm, but has a drawback in that the automated layout is limited to only some of its members. Therefore, additional research should be conducted on the development of advanced software through the diversification of the algorithm, automation of preprocessing of the mesh, and analysis of the relationships of all the members comprising the formwork.

An advanced GCode analyser for predicting the build time for additive manufacturing components

<p class="Abstract">Additive manufacturing is a technology for quickly fabricating physical models, functional prototypes, and small batches of parts by stacking two-dimensional layered features directly from computer-aided design data. One of the most important challenges in this sector relates to the capability to predict the build time in advance, since this is crucial to evaluating the production costs. In this paper, an accurate method for obtaining build-time is proposed. This method is based on an advanced GCode analyzer written in Python following an object-oriented paradigm for scalability and maintainability. Various examples are used to demonstrate the reliability of the algorithm, while its potential applications are also illustrated.</p>

Referencing the pectoralis major tendon for humeral stem height placement in reverse shoulder arthroplasty for fracture

BackgroundProximal humerus fractures remain a challenging problem, and reverse total shoulder arthroplasty (RSA) has demonstrated reliable outcomes in fracture applications. Despite this, guidelines for placement of the humeral component are lacking. MethodsTwelve cadaveric shoulders (6 cadaveric torsos) were utilized. An onlay RSA stem was placed with the lateral potion of the humeral cup positioned at the level of the greater tuberosity. Measurements were taken from the top of the pectoralis major tendon to the top of the humeral stem. A separate computer-aided analysis was conducted analyzing the height of an RSA humeral stem and an RSA humeral stem with a cup using values extrapolated from prior data. ResultsThe average distance from the top of the pectoralis to the top of the humeral stem was 4.0 cm (3.4 cm to 4.8 cm) with a standard deviation of 4.1. The humeral cup added an average of 9.1 mm. Computer-aided design data demonstrated the average height of the humeral stem was 3.9 cm above the superior aspect of the pectoralis tendon, and the average height with the humeral cup added was 4.8 cm. ConclusionBoth the cadaveric and computer-aided design data demonstrated a similar height for both the distances from the superior portion of the pectoralis to the superior aspect of an onlay RSA stem and the humeral cup. The measurement from the humeral cup may allow for translational use with inlay RSA humeral stems. This study demonstrates the superior border of the pectoralis major tendon to be a reliable landmark in RSA humeral stem placement. Level of evidenceLevel IV; Cadaveric Study

Constructing assembly design model capable of capturing and sharing semantic dynamic motion information in heterogeneous CAD systems

Over the last decades, collaborative assembly design has received much attention, which has provided fruitful results in terms of data models, knowledge-based, and top-down geometric modeling approaches, to name a few. Particularly, researchers have focused their efforts towards assembly relationships within product models, but have limited the scope to static assembly geometric description as currently stated in computer-aided design (CAD) systems. A disruptive vision is assumed in this research work, arguing that the assembly design itself presents a dynamic nature via, especially, dynamic motion. Such a paradigm shift requires an appropriate logical and semantic foundation to augment current CAD systems and data models’ capabilities with the capture of dynamic phenomena such as assembly motions and kinematic behaviors. Traditional CAD systems nowadays can handle the kinematics-related motion-related information; however, the interoperation of this motion-related information from one CAD system to the other is still a limitation of the interoperability standards. To tackle this research challenge, this paper aims at defining an original framework built upon a formal ontology to capture and share dynamic assembly motion among heterogeneous CAD systems. The formal ontology uses spatiotemporal mereotopology, which serves as a theoretical backbone to qualitatively describe the dynamic behavior of a product. This theory addresses the qualitative description of the temporal dimension over the spatial dimension of 3D objects. The proposed ontology is then enhanced to maintain semantic continuity of the spatial and temporal aspects embedded in assembly design ontology models. Built with a Web Ontology Language (OWL) data structure to interact with a CAD system and a motion visualization application, the ontology ensures the dynamic motion information capturing and sharing. SWRL (Semantic Web Rule Language) is utilized to show the semantic reasoning among the moving and non-moving parts of the product assembly. As a result, a semantic articulation ensuring flexibility and interoperability as a competitive industrial edge is demonstrated with proof of concept to be effective in a collaborative assembly design environment.

Optimisation of camera positions for optical coordinate measurement based on visible point analysis

In optical coordinate measurement using cameras, the number of images, and positions and orientations of the cameras, are critical to object accessibility and the accuracy of a measurement. In this paper, we propose a technique to optimise the number of cameras and the positions of these cameras for the measurement of a given object using visible point analysis of the object's computer aided design data. The visible point analysis technique is based on a hidden point removal approach; this technique is used to detect which surface points on the object are visible from a given camera position. A genetic algorithm is used to find the set of positions that provide optimum surface point density and overlap between views, while minimising the total number of camera images required. The genetic algorithm is used to minimise the measurement data processing time while maintaining optimum surface point density. We test this optimisation procedure on four artefacts and the measurements are shown to be comparable to that from a traceable contact co-ordinate measurement machine. We show that using our procedure improves the measurement quality compared to the more conventional approach of using equally spaced images. This work is part of a larger effort to fully automate and optimise optical coordinate measurement techniques.

Single Layer Formation of Plasma Based Wire Arc Additive Manufacturing

Wire and Arc Additive Manufacturing (WAAM) process is relatively a new approach to 3D metal printing technology. The process is capable of producing complex parts directly from 3D computer-aided design data by utilizing normal welding equipment. Gas metal arc welding, gas tungsten arc welding, and plasma arc welding are three different types of heat sources commonly used in WAAM to melt the welding wire. This approach is primarily different from the normal arc welding which is used to join materials. This is because in WAAM, materials are deposited layer by layer consecutively until a 3D structure is produced. In this study, the WAAM process is based on plasma arc welding. The study explores the effect of the processing parameters using a full factorial approach. Through the combination of these parameters, different types of deposition have been observed. These are little deposition, droplet deposition, discontinuous deposition and continuous deposition. The last one can be obtained at a specific combination of stand-off distance, speed and current. The recommended optimal parameters can produce the first layer, which is characterized by the continuous single-track formation. Continuous deposition is essential in WAAM as it is the foundation for producing a good 3D structure during layer-by-layer deposition.

On the environmental impacts of 3D printing technology

The introduction of new materials is tied to the rapid development of manufacturing processes. Additive manufacturing (AM) has been employed to fabricate a solid three-dimensional (3D) part directly from a computer-aided design (CAD) data. AM is an industrial process that has been widely employed in different industries in the past few years. In fact, this 3D printing is a rapid prototyping technology that involves a series of techniques. Although several challenges and limitations exist in the AM process currently, AM is expected to revolutionize the manufacturing process of engineering components. However, despite the numerous applications of AM techniques in various industries, their environmental impacts are not well documented. AM affords significant changes in production cost, energy consumption, and manufacturing lead times. All these issues have been considered to develop this technology to have higher efficiencies and lower environmental impacts. In this paper, we briefly review AM methods and discuss their environmental impacts. Furthermore, we present the main advantages and disadvantages of AM processes involving polymers. It can be concluded that AM is advantageous in some cases, exhibiting lower energy consumption and comprising shorter manufacturing processes. The analysis and discussion indicate the advantages, limitations, and future research directions for the industrial applications of AM.

Strength and Dimension Accuracy in Fused Deposition Modeling : A Comparative Study on Parts Making Using ABS and PLA Polymers

Rapid prototyping is a group of techniques used to quickly scale physical parts or assemblies using three-dimensional computer-aided design (CAD) data. The process of 3D printing constructs three-dimensional objects from CAD models, usually by adding layers by a layer of material in a row. Therefore it is also called making addictive manufacturing. Along with the development of rapid prototyping, there are many choices of materials on the market to make parts of 3D printing. The material can be in the solid filament, liquid resin, or powder. Solid filament FDM technology material is the most commonly used by industry — these materials such as ABS, PLA, PETG, HIPS, and others. In 3D printing products, several variables can be observed to produces specific responses desirable. Some of the responses are the efficiency of materials, dimensional accuracy of mechanical, and others. This research was conducted to compare ABS and PLA materials in the fused deposition modeling process. The strength and dimensional accuracy are the response that used in this study. The study reports that ABS has more significant tensile strength than PLA. The tensile strength of ABS is 7.66 MPa and 1.79 for PLA. PLA found has a more accurate dimension compare to ABS. Both on length and thickness, deviation of PLA lower than ABS. On a length, deviation of PLA was 0.06 mm and 0.86 for ABS. On thickness, deviation of PLA was 0.04 and 0.05 for ABS.

Design Procedure of a Topologically Optimized Scooter Frame Part

This article describes the design procedure of a topologically optimized scooter frame part. It is the rear heel of the frame, one of the four main parts of a scooter made with stainless steel 3D printing. The first part of the article deals with the design area definition and the determination of load cases for topology calculation. The second part describes the process of the topology optimization itself and the creation of the volume body based on the calculation results. Finally, the final control using an FEM (Finite Element Method) analysis and optimization of created Computer-Aided Design (CAD) data is shown. Part of the article is also a review of partial iterations and resulting versions of the designed part. Symmetry was used to define boundary conditions, which led to computing time savings, as well as during the CAD model creation, where non-parametric surfaces were mirrored to shorten the design time.

A gap balancing technique for adjusting the component gap in total knee arthroplasty using a navigation system

IntroductionRecently, some studies showed assessment of the component gap is important for determination of the implant-inserted condition during total knee arthroplasty (TKA). We perform the modified gap technique with adjustment of the virtual gap which estimated by computer-aided design (CAD) using navigation system. The purpose of this study was to compare the virtual gap (CAD-gap) with the actual gap after inserting a femoral trial component (Trial-gap), and examine the usefulness of the surgical technique. Materials and methodsThe subjects were 35 patients who underwent primary TKA using a navigation system and posterior-stabilized type TKA. The surgical procedure was to produce an extension gap, confirm the flexed CAD-gap on the navigation screen based on CAD data, and plan osteotomy of the femur. After osteotomy, the femoral component was inserted and the gap balance was measured. A tensor was used to adjust and measure the gap balance. Initial alignment, rotation of the femoral component, soft tissue balance in extension, final alignment after fixing all components, and the CAD- and Trial-gaps in both extension and flexion were evaluated. ResultsThe mean initial alignment angle, rotation angle of the femoral component, soft tissue balance angle and final alignment angle were 8.1 ± 4.2° varus, 3.5 ± 1.3°external rotation, 2.7 ± 2.5° varus and 0.4 ± 1.4° varus respectively. The mean medial and lateral CAD-gaps in extension were 10.8 ± 2.5 and 13.7 ± 2.5 mm, and the mean medial and lateral CAD-gaps in flexion were 12.2 ± 2.2 and 13.9 ± 2.7 mm. The equivalent Trial-gaps in extension and flexion were 10.5 ± 2.6 and 11.4 ± 3.1 mm, and 12.2 ± 2.5 and 14.4 ± 2.8 mm. The CAD- and Trial-gaps differed significantly only for lateral gaps in extension. ConclusionIn comparing the CAD-gap and the Trial-gap, only small difference was found in the lateral gap of extension. The other gaps in both extension and flexion were well maintained. We concluded adjustment of the CAD-gap during surgery using a navigation system can be used to adjust the actual component gap especially in the medial side.

A novel multi-brand robotic software interface for industrial additive manufacturing cells

A novel multi-brand robotic software interface for industrial additive manufacturing cells

Rapid Prototyping : An Effective Tool for Manufacturing of Intricate Geometries of Automotive Components : A Case Study

Tooling is one of the most important elements in the manufacturing process. To achieve the high quality requirements, moulds are traditionally made by CNC-machining, electro-discharge machining or conventional technologies. The term Rapid Prototyping (RP) refers to a group of technologies that can automatically construct physical model from Computer Aided Design data. Rapid Prototyping allows them to be made quicker and less expensively. The Rapid Prototyping techniques involves basic five step process like, Create a 3D CAD model of the required design, Convert the CAD model to STL format, Slice the STL file, Construct the model Layer by Layer and finally Clean and finish the model. Rapid Prototyping is widely used in fabrication of intricate parts of automotive, aerospace, medical and consumer products industries. Also especially moulds are made from RP model from Rapid Tooling. In this paper, a case study of manufacturing of engine head is taken. In contrast to construction of models by machining, based on the removal of material until the required form is achieved, RP model is made by adding material layer by layer until the whole part will be completed.

Mechanical investigation and optimization of parameter selection for Nylon material processed by FDM

Fused Deposition Modelling (FDM) is one type of additive manufacturing process, where the product is manufactured through layer by layer addition process with high accuracy using computer aided design data. 3-D printing technology is a growing sector of manufacturing, automotive, aerospace and many others. In all these fields it’s proven as the cost effective. In this research work, the 3D printed parts are designed according to ASTM standards and printed from a digital template file using the FDM machine. The material chosen for this 3-D printing parameter optimization is Nylon. In order to improve mechanical properties, tests like Ultimate Tensile Strength (UTS), impact strength, flexural strength and shore D hardness were processed through Taguchi L9 orthogonal array, It have been used with varying the input parameters like fill Density (FD) , Layer Height (LH) and Print Speed (PS). To study the influence of output parameters with respect to input parameters Analysis of Variance (ANOVA) was employed.