3D Scanning Research Articles

New data, new interpretations: Dzibanche monuments through the lenses of a 3D scanner

New data, new interpretations: Dzibanche monuments through the lenses of a 3D scanner

Computational Fluid Dynamics Study of Erosion on 900 MW Steam Turbine ND-45 Blades Using 3D Scanning.

This paper presents a comprehensive study on the impact of erosion on the flow characteristics through the blade of the last stage of a 900 MW steam turbine. The primary objective is to understand how surface erosion, caused by prolonged steam exposure, affects flow behavior and the overall efficiency of a 900 MW class turbine. The research process began with a 3D scan of the turbine blade, using advanced laser scanning technology to create a detailed geometric model. As one of the longest blades used in steam turbines, it posed both a technical challenge and was an innovative aspect of this study. The resulting 3D model served as the basis for numerical simulations using Computational Fluid Dynamic (CFD) methods, which allowed for the analysis of steam flow over the eroded blade surface. Key flow parameters, including velocity, pressure, and turbulence, were assessed to determine the impact of erosion. The study revealed significant changes in flow characteristics depending on the degree of erosion, providing valuable insights for turbine optimization and maintenance. The novelty of this research lies not only in the use of advanced scanning technologies but also in analyzing one of the longest blades in industrial practice, with findings that could enhance turbine efficiency and inform new erosion risk management strategies.

The rise of the Kaanuˀl kingdom and the city of Dzibanche

Abstract The Kaanuˀl dynasty ruled a hegemonic state with political influence over much of the Classic Maya Lowlands between a.d. 520 and 751. The present article introduces the subject for a special section of the journal, which refocuses attention on the archaeological zone of Dzibanche in southern Quintana Roo, Mexico, where new data are emerging about the origins of the Kaanuˀl dynasty, its urban organization, and its connections to neighboring centers. In this article, we present new data from a recent lidar survey as well as from previous work by Enrique Nalda's Instituto Nacional de Antropología e Historia (INAH) project to reevaluate Dzibanche's characteristics vis-à-vis its rise as a kingdom with far-reaching political influence. We complement these archaeological data with epigraphic information from new monuments and reanalysis of existing ones based on 3D scanning to update the list of Dzibanche rulers. We then revisit the chronology of Dzibanche's royal burials proposing correlations with known Early Classic Kaanuˀl rulers. Overall, the contributions to this special section present new perspectives on the Kaanuˀl's rise to power and its relationship with distant vassals in the crucial period of expansion into northern Peten, leading to the defeat of Tikal and eventually to its transition to a new dynastic seat at Calakmul in the a.d. 630s.

3D electrospray printing PEI-TMC nanofiltration membrane for efficient and long-term stable separation of Mg2+/Li+

The active layer of the thin film composite (TFC) nanofiltration membrane prepared by traditional interfacial polymerization (IP) was usually a non-homogeneous state with dense in the middle and loose on both sides. Such structure would reduce the stability of membrane in operation. In this paper, a novel electrospray polymerization nanofiltration (EPNF) membrane was fabricated for efficient and long-term stable separation for Mg2+/Li+ by multiple scan 3D electrospray printing technique. The active layer consisted of two homogeneous separation layers, the piperazine-trimesoyl chloride (PIP-TMC) inner layer and polyethyleneimine based (PEI-TMC) outer layer. With a fixed scan of inner layer, the effect of scan number of PEI-TMC outer layer on the performance of EPNF membrane was analyzed detailly from chemical structure and ion separation performance. Under the synergistic effect of electrostatic repulsion and pore size screening, the EPNF membrane achieved a Mg2+/Li+ separation factor of 36.28 and only 1.5 % performance loss in the operation of 150 h. The electrospray polymerization process presented unique advantages in preparing TFC nanofiltration membranes with long-term separation stability.

Hybrid acoustic modeling: far-field predictions from scanning 3D sound intensity data

This research introduces a novel methodology for predicting the far-field acoustic behavior of complex vibro-acoustic sources, utilizing 3D sound intensity data acquired through Scan&Paint 3D's continuous scanning technology. By combining this experimental dataset with the computational modeling capabilities of the commercial acoustic package Actran, we establish a hybrid method capable of accurately computing noise generated by intricate vibro-acoustic phenomena. The use of a 3D sound intensity probe, in combination with an infrared stereo camera, accelerates the acquisition of acoustic data across an extensive area. This approach not only delivers detailed insights into the source's near-field acoustic behavior but also provides inputs for the computational model, allowing us to model how the vibrating structure radiates. Extensive validation is performed by calculating prediction errors across multiple observation points, ensuring high quality far-field predictions. The integration of extensive experimental data with advanced computational modeling marks a significant leap forward in evaluating the far-field impact of complex acoustic sources. This allows the industrial user to assess the performance of multiple potential mitigation solutions through simulation, quickly, easily, and reliably.

Experimental study on the influence of horizontal stress difference coefficient on coal rock fracture

Hydraulic fracturing is a pressure-relief and permeability-enhancing technique widely used in the mining of low-permeability coal seams. The horizontal stress difference coefficient is an important factor that affects the fracture propagation during the fracturing. To study the mechanism of the hydraulic fracturing process, in this paper, the initiation and propagation of cracks under horizontal stress difference coefficient are studied by using the developed true triaxial hydraulic fracturing system. The fracture surface morphology was obtained by 3D scanner. The experimental results are verified by the mathematical model. The results show that the fracture pressure and the peak values of AE count rate and b value increase and the cumulative AE count decreases with the increase of the horizontal stress difference coefficient. After the first pressure drop, the “pressure built-up” in the specimen increases and the peak value of AE count rate decreases with the increased horizontal stress difference coefficient. The 3D scanning results show that when the horizontal stress difference coefficient is larger, the hydraulic fracture propagation is straighter and the fracture surface area is smaller. The experimental results are in good agreement with the theoretical values. The experimental results provide a basis for engineering practice.

Ultrasonography-Guided Dental Implant Surgery: A Feasibility Study.

To evaluate the feasibility of ultrasound-image-based computer-assisted implant planning and placement. Intraoral scans, cone-beam computerized tomography (CBCT), and ultrasound (US) scans with a custom positioning device were acquired in nine patients. Prosthetic-driven surgical guides were planned and fabricated based on ultrasound images and intraoral scans. Implants were then placed. Postoperative implant position was obtained intra-surgically by intraoral scan. Aside from the ultrasound-based plan, conventional implant planning was performed by the same operator on a pre-surgical CBCT for comparison. Linear deviations between ultrasound and CBCT-planned implant positions were measured and compared with the intra-surgical implant position, and the position deviations between two consecutive plannings were performed on the same CBCT by the same operator. The linear deviation between the 3D scan surface of the edentulous region and the ultrasonographic soft tissue profile segmentation was also assessed with reverse-engineering software. Means, standard deviations, and root mean square differences (RMSD) were calculated for every variable. All the ultrasound-planned implants were successfully placed, and no complications were recorded. The mean deviations in angles, shoulders, and apexes were 5.27 ± 1.75° (RMSD: 5.53°), 0.92 ± 0.26 mm (RMSD: 0.95 mm), and 1.41 ± 0.61 mm (RMSD: 1.53 mm), respectively, between the US and CBCT-planned implants; 2.63 ± 0.43° (RMSD: 2.66°), 1.16 ± 0.30 mm (RMSD: 1.19 mm), and 1.26 ± 0.27 mm (RMSD: 1.28 mm) between the planned implant and intra-surgically recorded positions; and 2.90 ± 1.36° (RMSD: 3.18°), 0.65 ± 0.27 mm (RMSD: 0.70 mm), and 0.99 ± 0.37 mm (RMSD: 1.05 mm) between two consecutive CBCTs planning performed by the same operator. The mean deviation between the 3D surfaces of model scans and ultrasound-derived soft tissue profile in the edentulous area was 0.19 ± 0.08 mm. Ultrasound-guided implant surgery represents a feasible non-ionizing alternative to conventional static guided implant surgical protocols for implant placement in sites with favorable characteristics.

Integrating Clay Modeling in Implant Fabrication for Craniofacial Defect.

Manufacturing craniofacial implants using 3-dimensional (3D) methods and computed tomography data has become popular. The image object for the defect is produced as the first step, followed by several methods to create the implant. The authors have used a novel method that combines clay modeling with 3D scanning to create implants for craniofacial contour reconstruction. This approach does not require complicated resources. The method allows for high customization and immediate modifications, resulting in implants that achieve an accurate fit and high patient satisfaction. It is particularly beneficial for addressing complex defects and achieving aesthetic improvements. In addition, it reduces the need for cumbersome digital processing and expensive materials, making it a practical and feasible solution for a wide range of craniofacial deformities.

Application of 3D scanning and computer simulation techniques to assess the shape accuracy of welded components

Application of 3D scanning and computer simulation techniques to assess the shape accuracy of welded components

Gaze tracking embedded collaborative robots for automated metrology and reverse engineering

Conventional geometric metrology, or three-dimensional (3D) scanning, and reverse engineering heavily rely on the experience of the operators. With an increasing need for automation, robot arms have been adopted for this task. However, due to the large variety of parts and designs, automated path planning could provide a scanning solution that may overlook the critical area, which could potentially deteriorate the scan results. This article explores the integration of collaborative robotics (cobots) with eye-tracking technology to improve the autonomous 3D scanning process. The primary objective of this study is to enhance the accuracy and efficiency of cobots in 3D scanning, particularly in the capture of functionally critical areas, and to provide a detailed description of regions with complex geometric features. The study develops a framework where the scanning path of the robot-driven scanner is partially guided by eye tracking data, that is, calibrated gaze tracking, to improve the automated 3D scanning process. This framework provides an innovative integration of human gaze movement with automatic robot path planning, providing a new way of human-autonomy teaming. Case studies are presented to present and validate the proposed framework to automatically improve the 3D point cloud collection process, specifically in areas that usually require human manual intervention to capture details.

Accurate prediction of disease-risk factors from volumetric medical scans by a deep vision model pre-trained with 2D scans.

The application of machine learning to tasks involving volumetric biomedical imaging is constrained by the limited availability of annotated datasets of three-dimensional (3D) scans for model training. Here we report a deep-learning model pre-trained on 2D scans (for which annotated data are relatively abundant) that accurately predicts disease-risk factors from 3D medical-scan modalities. The model, which we named SLIViT (for 'slice integration by vision transformer'), preprocesses a given volumetric scan into 2D images, extracts their feature map and integrates it into a single prediction. We evaluated the model in eight different learning tasks, including classification and regression for six datasets involving four volumetric imaging modalities (computed tomography, magnetic resonance imaging, optical coherence tomography and ultrasound). SLIViT consistently outperformed domain-specific state-of-the-art models and was typically as accurate as clinical specialists who had spent considerable time manually annotating the analysed scans. Automating diagnosis tasks involving volumetric scans may save valuable clinician hours, reduce data acquisition costs and duration, and help expedite medical research and clinical applications.

Influence of Blowing Musical Instruments on Geometrical Face Changes: 3D Evaluation Study.

This study examined changes in facial geometry while playing wind instruments. Nine musicians participated (6 men, 3 women, mean age 52 years) in part 1 of the study, and 3 musicians participated (3 women, mean age 41 years) in part 2. In part 1, the high and low notes of each instrument were selected as test sounds. Facial geometry data were recorded using a 3D scanner. In part 2, facial geometry data were recorded using a 4D scanner while a melody was played. Data were superimposed and analyzed using 3D analysis software. Numerical values and color maps of deviations were obtained. The results of part 1 revealed that the median 3D deviation was 1.1 mm (range 0.42-1.45 mm), indicating that facial geometry while playing high and low notes was varied. The results of part 2 showed that the stable part was the frontal region and dorsal part of the nose. The approach used in this study has potential applications for evaluating facial geometry during musical instrument performances.

Robot path planning for metrology in hybrid manufacturing

The objective of the wire arc additive manufacturing (WAAM) hybrid cell is to significantly reduce lead time associated with large scale parts. The WAAM process utilizes a 6 degree-of-freedom (DOF) robot manipulator in addition to a 2 DOF part positioner. After printing, the part is translated into position for scanning to inform the subtractive manufacturing process. Scanning in a manual setting can be a long and arduous process to generate scans of sufficient quality for the basis of informed machining. Effective path planning for scanning with the intent to reduce scanning time, increase quality of scans, and move toward a full automation of the hybrid manufacturing cell is investigated in this paper. Simulation software is used to create and verify path plans prior to importing and implementing on a 6 DOF robotic manipulator to which a GOM ATOS Q 3D scanner is mounted. The quality, amount of time necessary to produce, and number of scans required to produce a sufficient representation for machining are compared using three methods. The first method is a manual scanning configuration, the second is using a generalized path plan, and the third is using a geometry-based path plan.

Research on size optimization of 3D printed parts using Grey-Taguchi method

Abstract Fused deposition modeling (FDM) is one of the earliest developed 3D printing processes, which has the advantages of a clean processing environment, low overall manufacturing costs, and a variety of optional materials. However, it still has the disadvantages of low dimensional accuracy and poor surface quality of the molded workpiece. Therefore, how to solve this annoying problem has become an important research topic in the current industry-university-research fields. In this study, a square container with a bottom area of 48 mm×48 mm, a height of 30 mm, and a thin wall of 6 mm was used as the design object, and four controllable factors were adopted: layer thickness (A), nozzle temperature (B), printing speed (C), and forming path (D), combined with Grey- Taguchi’s experiments and calculations are carried out in order to achieve the purpose of optimizing the inner volume (IV) and inner diagonal length (IDL) of the square container (dual-objective quality characteristics). The experimental results show that within the selected printing parameter range, the optimized process parameter combination is layer thickness of 0.25 mm (A3), nozzle temperature of 190 °C (B1), printing speed of 50 mm/s (C3) and the molding direction of the annular surface (D2). Finally, use the GOM Inspect software (ATOS Q 3D scanner) and vernier caliper (VC) to compare the physical errors. According to the verification results, the errors of IV and IDL of the square container obtained by optimizing process parameters are 0.49% and 1.53%, and 3.76% and 6.33% respectively in GOM Inspect software and vernier caliper measurement. The results of this optimization process not only prove that the GOM Inspect software has a considerable degree of accuracy, but also can be used as a means to improve FDM multi-quality printing process optimization when combined with the Grey-Taguchi method.

Modeling wear of different surface layers of agricultural tools in soil abrasive mass

Uniform quantitative measures have not been developed to identify the areas with the greatest intensification of tool wear. Therefore, this paper developed original approach to assess the wear of cutting elements by identifying the intensity of local volumetric wear. A tribological test was conducted under natural operating conditions in two soil types: sandy loam and loam. The specimens were mounted on a 9-tined cultivator with spring tines aggregated with an agricultural tractor. A method was developed to discretise the local volume changes of a component using surface scanning models developed from 3D scanning. The notion of the rake angle has been defined, allowing the assessment of changes in the shape of the element during wear. The practical usefulness of the developed method was verified on three types of surface layers, i.e. 38GSA steel, ELHARD70 deposited on it, and a G10 layer of carbide. For each of the tested variants, local volumetric consumption was defined based on the identification of the wear grid. These should be the basis for developing the technology of surface strengthening of elements. The work confirmed the complexity of the process of wear of working elements in natural soil conditions, presented in many research works. A different course of wear of the 38GSA steel and the Elhard 70 weld layer was shown, depending on the type of treated soil. In the case of samples made of G10 cemented carbide, the largest volumetric wear for heavy soil occurred outside the place of reinforcement application. The highest volumetric wear in the front zone was recorded for 38GSA steel in heavy soil. Wear results from the modelling are similar to those obtained from the experiment under natural conditions in light soil using the nominal model (CAD) and the actual friction surface.

Experimental study on the rock breaking effect of different tooth shapes of inserted teeth in a hobbing-cone hybrid PDC bit under complex stress environment

The hobbing-cone hybrid PDC bit has emerged with the increasing exploitation of deep oil and gas resources. As an important component of new bits, studying the mechanism of toothed fracturing of deep rocks is crucial for improving rock-breaking efficiency. In this paper, the spherical teeth and conical teeth were used to intrude sandstone under different confining pressures, and the brittleness index (BIm), specific energy (SE), and average fragment size (dm) were used to analyze the rock-breaking effect. The 3D contour scanner quantitatively analyzed the crushing pit area. Finally, the in-situ CT scanning and discrete element numerical simulation were used to summarize the crack propagation law. The results show that with the increase of confining pressure, the BIm of inserted teeth increases continuously, and the growth rate of conical teeth increases, while that of spherical teeth decreases. The SE and dm exhibit a symmetrical distribution with a confining pressure of 10MPa as the axis of symmetry. When the difference in principal stress is 5MPa, the SE is the lowest point, the rock-breaking efficiency is the highest, and the corresponding dm is at the highest point, but the curve trend is the opposite. When the stress difference is 5MPa, it is conducive to propagating surface cracks, thus forming a larger crushing area and the highest rock-breaking efficiency. Based on CT results, the dense particle core is formed near the inserted teeth, and that of the spherical teeth is located below. In contrast, that of the conical teeth is located on the side, which is also the reason for the difference in crack propagation between different tooth shapes.

Proof-of-concept of real-time electromagnetic guidance for gynecologic interstitial catheters in high dose rate brachytherapy

Background and PurposeThe addition of interstitial needles to intracavitary gynecologic (GYN) high dose rate (HDR) brachytherapy has been shown to improve target coverage and organs-at-risk (OAR) sparing. However, no commercial solution allows real-time guidance of interstitial catheter placement. This phantom study aimed to evaluate the feasibility of an electromagnetic (EM) tracking system guidance workflow for GYN HDR brachytherapy treatment in a magnetic resonance imaging (MRI) and real-time transrectal ultrasound (TRUS) fusion scenario. Materials and MethodsA clinical investigational system combining a treatment planning system and the EM tracking technology was used. The 3D T2 weighted magnetic resonance (MR) image set of a patient treated with intracavitary and interstitial HDR brachytherapy was retrospectively chosen. The MR image set was used to delineate the target and the OARs. A preplan was generated to determine needles positions in advance. The implant was reproduced in a water phantom. A 3D TRUS scan was acquired, and a rigid registration between the MR and the TRUS images was performed. ResultsThe accuracy of the EM tracking system was < 1 mm for both the sagittal and the transverse modes of the TRUS probe. Contours that were delineated on the MRI were propagated on the TRUS images after the rigid registration. Needle insertion was successfully guided in real time with the EM tracking system on the TRUS live image using the MRI contours for guidance. ConclusionBased on this proof-of-concept, real-time EM-guidance of interstitial needle for GYN HDR brachytherapy appears to be feasible.

Study on dynamic mechanical characteristics of specimens with cavity under prestressing conditions

Deep defect-bearing rock bodies are typically subjected to in-situ stresses and dynamic loading. This study investigates the failure characteristics of cavity specimens containing square holes and circular holes by employing different static-dynamic coupled loading experiments using a triaxial SHPB device that can facilitate static-dynamic coupled loading. Based on SHPB experiments, strain field analysis, and 3D laser scanning modelling techniques, this study comparatively analyses the effects of impact velocity and stress environment on the strength, stress–strain curve characteristics, dynamic damage process, and damage characteristics of square and circular hole specimens. The experiment proposes using elevation maps to characterise the damage characteristics of the specimen under impact loading. It ultimately relates the experimental results to field rockbursts and tunnel excavation, which has significant implications for guiding field practice to a certain extent. The experimental results showed that the stress environment under dynamic perturbation has a bidirectional effect (both favourable and unfavourable) on the strength of the specimens containing defects, which manifests as a difference in the characteristics of the stress–strain curves. When damage occurs near the cavity of the specimen, the stress–strain curve exhibits type I characteristics. When the entire specimen destabilises, the stress–strain curve shows type II characteristics. Under the same conditions, the strength of the specimens with square holes is significantly lower than those with circular holes. The 3D laser scanning results indicated that the damage is primarily concentrated near the cavity, and compared to the circular hole specimen, the damage area of the square hole specimen is mainly attributed to shear-tension damage, resulting in the collapse of the slabs on the upper and lower sides of the cavity.

Shape-programmable hard-magnetic soft actuators with high magnetic particle content via digital light processing method

In this work, we developed a novel hard-magnetic photosensitive suspension with high solid loadings of 50 wt% for digital light processing 3D printing. The suspension combining photosensitive resin and reactive diluent can retain stability for 6 h. The printed materials from the suspension achieve a low modulus of below 900 kPa and high remanence of 83.7 kA/m. The suspension’s cure behavior was studied in detail to obtain the optimal printing parameters. The printing error of the small structures with feature size of about 1000 μm is kept below 20 %. Moreover, we proposed an efficient magnetization programming strategy for hard-magnetic soft actuators with desirable shapes based on the rod model considering the non-magnetic load. The accuracy and reliability of the strategy are verified by the experiment results. Finally, we designed and fabricated a “flower” using our method, achieving its closing action in accordance with the prescribed shape.

Simultaneous Color- and Dose-Controlled Thiol-Ene Resins for Multimodulus 3D Printing with Programmable Interfacial Gradients.

Drawing inspiration from nature's own intricate designs, synthetic multimaterial structures have the potential to offer properties and functionality that exceed those of the individual components. However, several contemporary hurdles, from a lack of efficient chemistries to processing constraints, preclude the rapid and precise manufacturing of such materials. Herein, the development of a photocurable resin comprising color-selective initiators is reported, triggering disparate polymerization mechanisms between acrylate and thiol functionality. Exposure of the resin to UV light (365nm) leads to the formation of a rigid, highly crosslinked network via a radical chain-growth mechanism, while violet light (405nm) forms a soft, lightly crosslinked network via an anionic step-growth mechanism. The efficient photocurable resin is employed in multicolor digital light processing 3D printing to provide structures with moduli spanning over two orders of magnitude. Furthermore, local intensity (i.e., grayscale) control enables the formation of programmable stiffness gradients with ≈150× change in modulus occurring across sharp (≈200µm) and shallow (≈9mm) interfaces, mimetic of the human knee entheses and squid beaks, respectively. This study provides composition-processing-property relationships to inform advanced manufacturing of next-generation multimaterial objects having a myriad of applications from healthcare to education.