Replicas Fabrication by Laser Scanner and Additive Manufacturing: A Preliminary Investigation

2019 ◽  
Author(s):  
Marco Rossoni ◽  
Giorgio Colombo
Keyword(s):  
Preliminary Investigation ◽  
Laser Scanner ◽  
Deposition Process ◽  
Measurement Tool ◽  
3D Printer ◽  
Fused Filament Fabrication ◽  
Polygonal Mesh ◽  
G Code ◽  
Topological Errors

Abstract This paper presents a preliminary investigation on the workflow that allows to replicate object by using 3D laser scanner and a desktop fused filament fabrication 3D printer. Pitfalls and limitations of those technologies will be pointed out in order to find the bottleneck of the workflow, paying specific attention to what concerns the digital workflow from the acquisition to the generation of the g-code. The findings and conclusions are drawn from a case study that has been carried out using the minimum amount of human intervention, especially during the digital postprocessing of the data. The objects under investigation is a broken car door handle. Firstly, it has been digitalized using a 3D laser scanner properly calibrated and set. The accuracy, precision and resolution of the measurement tool have been recorded and the as-is acquired data has been checked against topological errors. The as-is acquired model has been compared with the original geometry. The 3d polygonal mesh has been prepared for being printed: the material, machine and process parameters have been chosen. A simulation of the deposition process to estimate warps and deviation from the nominal geometry was carried out. Finally, the object has been additively manufactured using a desktop Fused Filament Fabrication machine: the printed object has been again compared with the original geometry.

Results of studying the dimensional accuracy of the bases of complete removable prostheses made using 3D printing and traditional technologies

2020 ◽  
pp. 34-39
Author(s):  
Vokulova Yu.A. Vokulova ◽  
E.N. Zhulev
Keyword(s):  
3D Printing ◽  
Traditional Method ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Digital Technologies ◽  
Dimensional Accuracy ◽  
3D Printer ◽  
Significance Level ◽  
Average Value ◽  
The Difference

This article presents the results of studying the dimensional accuracy of the bases of complete removable prostheses made using a 3D printer and the traditional method. Bases of complete removable prostheses were made using an intraoral laser scanner iTero Cadent (USA) and a 3D printer Asiga Max UV (Australia). To study the dimensional accuracy of the bases of complete removable prostheses, we used the DentalCAD 2.2 Valletta software. The Nonparametric Wilcoxon W-test was used for statistical analysis of the obtained data. We found that the average value of the difference with the standard for bases made using digital technologies is 0.08744±0.0484 mm. The average value of the difference with the standard for bases made by the traditional method is 0.5654±0.1611 mm. Based on these data, we concluded that the bases of complete removable prostheses made using modern digital technologies (intraoral laser scanning and 3D printer) have a higher dimensional accuracy compared to the bases of complete removable prostheses made using the traditional method with a significance level of p<0.05 (Wilcoxon's W-test=0, p=0.031). Keywords: digital technologies in dentistry, digital impressions, intraoral scanner, 3D printing, ExoCAD, complete removable dentures.

Obtaining morphometric variables from gullies using two methods of interpolation laser scanner data: the case study of Vassouras, Brazil

2020 ◽  
Vol 17 (12) ◽  
pp. 3012-3023
Author(s):  
Carlos Magno Moreira de Oliveira ◽  
Márcio Rocha Francelino ◽  
Bruno Araujo Furtado de Mendonça ◽  
Isabela Queiroz Ramos
Keyword(s):  
Laser Scanner ◽  
Scanner Data

scholarly journals On the Sensitivity of the Parameters of the Intensity-Based Stochastic Model for Terrestrial Laser Scanner. Case Study: B-Spline Approximation

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2964 ◽  
Author(s):  
Gaël Kermarrec ◽  
Hamza Alkhatib ◽  
Ingo Neumann
Keyword(s):  
Stochastic Model ◽  
Good Description ◽  
Spline Approximation ◽  
Laser Scanner ◽  
Terrestrial Laser Scanner ◽  
Case Scenario ◽  
Constant Variance ◽  
Power Law Function ◽  
Stochastic Properties

For a trustworthy least-squares (LS) solution, a good description of the stochastic properties of the measurements is indispensable. For a terrestrial laser scanner (TLS), the range variance can be described by a power law function with respect to the intensity of the reflected signal. The power and scaling factors depend on the laser scanner under consideration, and could be accurately determined by means of calibrations in 1d mode or residual analysis of LS adjustment. However, such procedures complicate significantly the use of empirical intensity models (IM). The extent to which a point-wise weighting is suitable when the derived variance covariance matrix (VCM) is further used in a LS adjustment remains moreover questionable. Thanks to closed loop simulations, where both the true geometry and stochastic model are under control, we investigate how variations of the parameters of the IM affect the results of a LS adjustment. As a case study, we consider the determination of the Cartesian coordinates of the control points (CP) from a B-splines curve. We show that a constant variance can be assessed to all the points of an object having homogeneous properties, without affecting the a posteriori variance factor or the loss of efficiency of the LS solution. The results from a real case scenario highlight that the conclusions of the simulations stay valid even for more challenging geometries. A procedure to determine the range variance is proposed to simplify the computation of the VCM.

scholarly journals Digital surveying and 3D modelling structural shape pipelines for instability monitoring in historical buildings: a strategy of versatile mesh models for ruined and endangered heritage

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 84
Author(s):  
Raffaella De Marco ◽  
Sandro Parrinello
Keyword(s):  
Laser Scanner ◽  
Structural Behaviour ◽  
Structural Shape ◽  
Built Heritage ◽  
Levels Of Detail ◽  
Aerial Vehicle ◽  
The Church ◽  
Mesh Models

Cultural heritage and the attendant variety of built heritage demands a scientific approach from European committees: one related to the difficulties in its protection and management. This is primarily due to the lack of emergency protocols related to the structural knowledge and documentation pertaining to architecture and its ruins, specifically in terms of the goals of protection and intervention for endangered heritage affected by mechanical instabilities. Here, we focus on a rapid and reliable structural documentation pipeline for application to historical built heritage, and we introduce a case study of the Church of the Annunciation in Pokcha, Russia, while we also review the incorporation of integrated 3D survey products into reality-based models. This practice increases the possibility of systematising data through methodological phases and controlling the quality of numerical components into 3D polygonal meshes, with millimetric levels of detail and triangulation through the integration of terrestrial laser scanner and unmanned aerial vehicle survey data. These models are aimed at emphasising morphological qualities related to structural behaviour, thus highlighting areas of deformation and instability of the architectural system for analysis via computational platforms in view of obtaining information related to tensional behaviour and emergency risks.

Material Flow Rate Estimation in Material Extrusion Additive Manufacturing

2021 ◽  
Vol 13 (1) ◽  
pp. 46-56
Author(s):  
G.P. Greeff
Keyword(s):  
Additive Manufacturing ◽  
Flow Rate ◽  
Material Flow ◽  
Fused Deposition Modeling ◽  
Volumetric Flow Rate ◽  
Cost Effective ◽  
Fused Filament Fabrication ◽  
Material Extrusion ◽  
Fused Deposition ◽  
G Code

The additive manufacturing of products promises exciting possibilities. Measurement methodologies, which measure an in-process dataset of these products and interpret the results, are essential. However, before developing such a level of quality assurance several in-process measurands must be realized. One of these is the material flow rate, or rate of adding material during the additive manufacturing process. Yet, measuring this rate directly in material extrusion additive manufacturing presents challenges. This work presents two indirect methods to estimate the volumetric flow rate at the liquefier exit in material extrusion, specifically in Fused Deposition Modeling or Fused Filament Fabrication. The methods are cost effective and may be applied in future sensor integration. The first method is an optical filament feed rate and width measurement and the second is based on the liquefier pressure. Both are used to indirectly estimate the volumetric flow rate. The work also includes a description of linking the G-code command to the final print result, which may be used to create a per extrusion command model of the part.

Forest fuel assessment by LiDAR data. A case study in NE Italy

2021 ◽  
Author(s):  
Flavio Taccaliti ◽  
Lorenzo Venturini ◽  
Niccolò Marchi ◽  
Emanuele Lingua
Keyword(s):  
Laser Scanner ◽  
Remote Sensing Data ◽  
Statistical Modelling ◽  
Pinus Nigra ◽  
Simulation Software ◽  
Lidar Data ◽  
Special Focus ◽  
Forest Fuels ◽  
Behaviour Simulation

&lt;p&gt;Fuel management is a crucial action to maintain wildland fires under the threshold of manageability; hence, in order to allocate resources in the best way, wildland fuel mapping is regarded as a necessary tool by land managers. Several studies have used Aerial Laser Scanner (ALS) data to estimate forest fuels characteristics at plot level, but few have extended such estimates at a zonal level.&lt;/p&gt;&lt;p&gt;In the context of the EU Interreg Project CROSSIT SAFER, a test of the possibilities of ALS data to predict fuels attributes has been performed in three different areas: an alpine basin, a coastal wildland-urban interface and a karstic highland. Eighteen sampling plots have been laid out over 6 forest categories, with a special focus on &lt;em&gt;Pinus nigra&lt;/em&gt; J. F. Arnold artificial forests. Low density (average 4 points/m&lt;sup&gt;2&lt;/sup&gt;) discrete return LiDAR data has been analysed with FUSION, a free point cloud analysis software tailored to forestry purposes; field and remote sensing data have been connected with simple statistical modelling and results have been spatialised over the case study areas to provide wall-to-wall inputs for FLAMMAP fire behaviour simulation software.&lt;/p&gt;&lt;p&gt;Resulting maps can be of relevance for land managers to better highlight the most vulnerable or fire prone areas at a mesoscale administrative level. Limitations and room for improvement are pointed out, in the view that land management should keep updated with the latest technology available.&lt;/p&gt;

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