scholarly journals The advantages of combining 3D printing with turning process. Case study

2021 ◽  
Vol 343 ◽  
pp. 02010
Author(s):  
Dan Claudiu Negrău ◽  
Gavril Grebenisan ◽  
Ion Cosmin Gherghea ◽  
Daniel Anton

The paper presents a case study which the additive manufacturing technology is combined with finishing process by cutting operations (turning) for manufacturing a part. The part was manufactured through additive manufacturing, using a 3D printer and the and the finishing process is performed by a lathe, resulting in technological properties and the corresponding dimensional accuracy. The research paper also contains the analysis of the roughness and other properties of the material from which the final part will be made. The manufactured part will be used as a support for the blades of a fan during the assembly process, which emphasizes that a part obtained by additive manufacturing (3D printing) can replace a part obtained by casting or fabrication by total cutting. In conclusion, obtaining the manufactured part by combining the two manufacturing processes, the lead time and the production cost has been significantly reduced, while the quality of the obtained product also increased, obtaining a very good roughness.

2021 ◽  
Vol 12 (2) ◽  
pp. 371-380
Author(s):  
Sally Cahyati ◽  
◽  
Haris Risqy Aziz

Rapid Prototyping (RP) is a manufacturing process that produces a 3D model CAD to be a real product rapidly by using additive manufacturing technology. In this case, the product will print layer by layer uses a 3D printer machine. The 3D printer requires slicer software to convert CAD data into data that a 3D printer machine can read. Research is done to analyze the effect of three kinds of slicer software on 3D printing objects on the accuracy and surface roughness of the product. The 3D model CAD is sliced using three different slicer software, namely Ideamaker, Repetier Host, and Cura. The slice model result from each slicer will be printed on a 3D printer machine with the same process parameters to be compared. Then the product's dimensional and surface roughness will be measured to determine the effect of each slicer on product quality. The best quality of the product reflected the most suitable slicer software for the 3D printing machine that used. The best results achieved by Cura slicer because it has resulted in small dimensional deviations (max 0,0308±0,0079) and stabile high surface roughness of the product (max 1,585+059).


Author(s):  
Vokulova Yu.A. Vokulova ◽  
E.N. Zhulev

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.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoyu Zhao ◽  
Ye Zhao ◽  
Ming-De Li ◽  
Zhong’an Li ◽  
Haiyan Peng ◽  
...  

AbstractPhotopolymerization-based three-dimensional (3D) printing can enable customized manufacturing that is difficult to achieve through other traditional means. Nevertheless, it remains challenging to achieve efficient 3D printing due to the compromise between print speed and resolution. Herein, we report an efficient 3D printing approach based on the photooxidation of ketocoumarin that functions as the photosensitizer during photopolymerization, which can simultaneously deliver high print speed (5.1 cm h−1) and high print resolution (23 μm) on a common 3D printer. Mechanistically, the initiating radical and deethylated ketocoumarin are both generated upon visible light exposure, with the former giving rise to rapid photopolymerization and high print speed while the latter ensuring high print resolution by confining the light penetration. By comparison, the printed feature is hard to identify when the ketocoumarin encounters photoreduction due to the increased lateral photopolymerization. The proposed approach here provides a viable solution towards efficient additive manufacturing by controlling the photoreaction of photosensitizers during photopolymerization.


Author(s):  
Dylan Bender ◽  
Ahmad Barari

This paper presents a methodology to find the optimum build orientation in the additive manufacturing of topologically optimized structural parts. The outlined methodology is based on applying a differential operator to the density distribution matrix of a topologically optimized design. The methodology is developed for 2D parts, where the profile of the geometry is constant. The 2D spatial difference operator effectively calculates the elemental density gradient vector, ultimately used to calculate the angles between i) overhanging surfaces of a topology optimized design, and ii) the build platform of a 3D printer. These angles, referred to as build angles, are used to estimate the relative amount of supporting structure required to print the design at a prescribed part orientation. This methodology can potentially be adopted to simulate the additive manufacturing surface quality of density based, structural topology optimization designs.


2021 ◽  
Vol 1027 ◽  
pp. 136-140
Author(s):  
Sze Yi Mak ◽  
Kwong Leong Tam ◽  
Ching Hang Bob Yung ◽  
Wing Fung Edmond Yau

Metal additive manufacturing has found broad applications in diverse disciplines. Post processing to homogenize and improve surface finishing remains a critical challenge to additive manufacturing. We propose a novel one-stop solution of adopting hybrid metal 3D printing to streamlining the additive manufacturing workflow as well as to improve surface roughness quality of selective interior surface of the printed parts. This work has great potential in medical and aerospace industries where complicated and high-precision additive manufacturing is anticipated.


History of additive manufacturing started in the 1980s in Japan. Stereolithography was invented first in 1983. After that tens of other techniques were invented under the common name 3D printing. When stereolithography was invented rapid prototyping did not exists. Tree years later new technique was invented: selective laser sintering (SLS). First commercial SLS was in 1990. At the end of 20t century, first bio-printer was developed. Using bio materials, first kidney was 3D printed. Ten years later, first 3D Printer in the kit was launched to the market. Today we have large scale printers that printed large 3D objects such are cars. 3D printing will be used for printing everything everywhere. List of pros and cons questions rising every day.


2020 ◽  
Vol 90 (19-20) ◽  
pp. 2304-2321
Author(s):  
Olivia Ho-Yi Fung ◽  
Joanne Yip ◽  
Mei-Chun Cheung ◽  
Kit-Lun Yick ◽  
Kenny Yat-Hong Kwan ◽  
...  

Bracing is the most common non-operative treatment option for patients with adolescent idiopathic scoliosis (AIS). However, existing brace designs have deficiencies, including a long production lead time and low patient compliance caused by the negative impacts of bracing on quality of life (QoL). The aim of this study was to address these problems by developing a new textile-based scoliosis brace in accordance with the biomechanics used in the existing braces for spinal correction. A case study of interface pressure had been carried out to determine the optimum combination of pads to be used in the proposed brace to correct a scoliotic spine. AIS patients who were undergoing hard brace treatment were recruited to complete a questionnaire (BrQ) on hard braces and on the proposed brace. The BrQ scores of the two types of braces were compared to assess their respective impacts on the QoL. The findings show that the proposed brace can address the issue of patient compliance by reducing the impact of bracing on QoL, and shorten the production lead time through incorporation of the mass customization concept into the design. Similar to most of the commonly-used scoliosis braces, the selected combination of pads used in the proposed brace for spinal correction shows a sufficient amount of exerted pressure and a similar function of active spinal correction.


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1941
Author(s):  
Aurel Tulcan ◽  
Mircea Dorin Vasilescu ◽  
Liliana Tulcan

The objective of this paper is to determine how the supporting structure in the DLP 3D printing process has influences on the characteristics of the flat and cylindrical surfaces. The part is printed by using the Light Control Digital (LCD) 3D printer technology. A Coordinate Measuring Machine (CMM) with contact probes is used for measuring the physical characteristics of the printed part. Two types of experiment were chosen by the authors to be made. The first part takes into consideration the influence of the density of the generated supports, at the bottom of the printed body on the characteristics of the flat surface. In parallel, it is studying the impact of support density on the dimension and quality of the surface. In the second part of the experiment, the influence of the printed supports dimension on the flatness, straightness and roundness of the printed elements were examined. It can be observed that both the numerical and dimensional optimum zones of the support structure for a prismatic element could be determined, according to two experiments carried out and the processing of the resulting data. Based on standardized data of flatness, straightness and roundness, it is possible to put in accord the values determined by measurement within the limits of standardized values.


Author(s):  
Wei Yang ◽  
Jialei Chen ◽  
Kamran Paynabar ◽  
Chuck Zhang

Abstract Additive Manufacturing (AM) is an emerging manufacturing technology that plays a growing role in both industrial and consumer settings. However, security concerns of the AM have been raised among researchers. In this paper, we present an online detection mechanism for the malicious attempts on AM system, which taps into both audios and videos collected during the actual printing process. For audio signals, we propose to monitor the characteristics or patterns in the spectrogram via the Wasserstain metric. For video signals, we present a path reconstruction method which effectively monitors the motion of the printer extruder. We then show the effectiveness of our methods in a case study using Ender 3D printer, where the cyber-incidence of modifying the internal fill density can be easily identified in an online manner.


2021 ◽  
Vol 11 (18) ◽  
pp. 8545
Author(s):  
So-Ree Hwang ◽  
Min-Soo Park

Additive manufacturing, commonly called 3D printing, has been studied extensively because it can be used to fabricate complex structures; however, polymer-based 3D printing has limitations in terms of implementing certain functionalities, so it is limited in the production of conceptual prototypes. As such, polymer-based composites and multi-material 3D printing are being studied as alternatives. In this study, a DLP 3D printer capable of printing multiple composite materials was fabricated using a movable separator and structures with various properties were fabricated by selectively printing two composite materials. After the specimen was fabricated based on the ASTM, the basic mechanical properties of the structure were compared through a 3-point bending test and a ball rebound test. Through this, it was shown that structures with various mechanical properties can be fabricated using the proposed movable-separator-based DLP process. In addition, it was shown that this process can be used to fabricate anisotropic structures, whose properties vary depending on the direction of the force applied to the structure. By fabricating multi-joint grippers with varying levels of flexibility, it was shown that the proposed process can be applied in the fabrication of soft robots as well.


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