additive manufacturing technology
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Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 132
Author(s):  
Doina Raducanu ◽  
Vasile Danut Cojocaru ◽  
Anna Nocivin ◽  
Radu Hendea ◽  
Steliana Ivanescu ◽  
...  

The aim of the present paper is to apply the mechanical alloying process to obtain from powder components a new biodegradable Mg-based alloy powder from the system Mg-xZn-Zr-Ca, with high biomechanical and biochemical performance. Various processing parameters for mechanical alloying have been experimented with the ultimate goal to establish an efficient processing route for the production of small biodegradable parts for the medical domain. It has been observed that for the same milling parameters, the composition of the powders has influenced the powder size and shape. On the other hand, for the same composition, the highest experimented milling speed and time conduct to finer powder particles, almost round-shaped, without pores or various inclusions. The most uniform size has been obtained for the powder sample with 10 wt.%Zn. These powders were finally processed by selective laser melting, an additive manufacturing technology, to obtain a homogeneous experimental sample, without cracking, for future more systematical trials.


2021 ◽  
pp. 1-22
Author(s):  
Veeman Dhinakaran ◽  
Mahesh Varsha Shree ◽  
Thimmaiah Jagadeesha ◽  
Madabushi Swapna Sai

Machines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 354
Author(s):  
Yanchao Fan ◽  
Deyi Dong ◽  
Chao Li ◽  
Yuxin Sun ◽  
Zhiyu Zhang ◽  
...  

As one of the most-critical components in space optical cameras, the performance of space mirrors directly affects the imaging quality of space optical cameras, and the lightweight form of mirror blanks is a key factor affecting the structural quality and the surface-shape accuracy of mirrors. For the design requirements of lightweight and high surface-shape accuracy with space mirrors, this study proposes a design and manufacturing method that integrates topology-optimization with additive-manufacturing technology. This article firstly introduced the basic process and key technologies of space-mirror design and analyzed the superiority of combining a topology-optimized configuration design and additive-manufacturing technology; secondly, the topology-optimized design method of a back-open-structure mirror was used to complete the scheme design of a Φ260 mm aperture mirror; finally, the laser selective-melting manufacturing technology was used to complete the Φ260 mm aperture mirror blank. The mirror and its support structure were assembled and tested in a modal mode; the resonant frequencies of the mirror assembly were all over 600 Hz; and the deviation from the analytical results was within 2%. The optical surface of the mirror was turned by the single-point diamond-turning (SPDT) technique. The accuracy of the optical surface was checked by a Zygo interferometer. The RMS accuracy of the mirror surface was 0.041λ (λ is the wavelength; λ = 632 nm). In the test of the influence of gravity on the surface-shape accuracy, the mirror was turned over, which was equivalent to twice the gravity, and the RMS of the mirror surface-shape accuracy was 0.043λ, which met the requirement. The verification results show that the mirror designed and fabricated by the additive-manufacturing-based mirror-topology-optimization method can be prepared by the existing process, and the machinability and mechanical properties can meet the requirements, which provides an effective development method for improving the structural design and optimizing the manufacturing of space reflectors.


TEM Journal ◽  
2021 ◽  
pp. 1895-1899
Author(s):  
Martin Pollák ◽  
Marek Kočiško

The combination of two rapidly evolving technologies such as additive manufacturing technology and robotics opens up a wide potential for solving new production tasks. In advance, several challenges need to be addressed in order to intensify the possibilities for developing the combination of these technologies. The aim of the article is to point out the possibility of designing a simple universal printing system for the collaborative robot UR5 with an orientation on the need to implement 3D printing. The solution proposed in this way makes it possible to simplify the design of the movements to reduce any further structural modifications and also to reduce the potential mechanical deficiencies of the structure of the printing device.


Author(s):  
Weiguang Yang ◽  
Xi Wang ◽  
Hai Zhou ◽  
Ti Zhou

Abstract The lower surface hardness limits the further application of 316 L stainless steel. In this study, selective laser melting (SLM)/laser metal deposition (LMD) composite additive manufacturing technology was used to prepare five kinds of 316L-nano-TiC cermet strengthening layers on the surface of 316L stainless steel, and to study the effect of nano-TiC particle content on the microstructure and the influence of microhardness. Use Laser microscope, scanning electron microscope (SEM), X-ray diffractometer (XRD) to analyze the structure, element distribution and phase composition of the strengthening layer. The hardness of the strengthened layer was analyzed using a Vickers micro-hardness tester. The study found that the composite SLM/LMD formed samples changed continuously from LMD forming to SLM forming, showing good metallurgical bonding. Diffusion of TiC particles was observed in the SLM strengthening layer, and TiC phase was detected in the strengthening layer. Compared with the 316L matrix, the microhardness of the strengthened layer is significantly improved. When 50wt% TiC is added, the average hardness of the strengthened layer is 1.9 times that of the 316L matrix, and the highest is 408.9HV. The results of this study show that the strengthening layer manufactured by composite additive materials can effectively improve the hardness of the 316L stainless steel matrix. As the content of nano-TiC in the preset powder increases, the microhardness of the strengthening layer first increases and then decreases, and the hardness of the 50wt% TiC strengthening layer is the highest. There are distributed nano-TiC particles in the structure of the strengthening layer, and the distribution of nano-TiC particles in the 50wt% TiC strengthening layer is more uniform than other samples. This research provides a new reference for the strengthening of 316L stainless steel through SLM/LMD composite additive manufacturing technology and the addition of nano-TiC particles.


Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1731
Author(s):  
Bo Qian ◽  
Hongri Fan ◽  
Gang Liu ◽  
Jianrui Zhang ◽  
Pei Li

The additive manufacturing technology of laser-based powder bed fusion (L-PBF), which is used to produce boiling heat transfer structures, offers a high processing flexibility and can provide lattice structures with a high surface-to-volume ratio. As an important part of the phased array radar, the plentiful transmit/receive (T/R) modules can generate considerable heat. Targeting this local overheating problem, this study discusses the pass design, the optimal formation process, and boiling heat transfer performance of microchannel liquid-cooled plates based on L-PBF additive manufacturing technology. The optimum design and process parameters were obtained by performing basic channel experiments. On this basis, the design and formation experiments of the microchannel structure were performed, and then the porosity and pore morphology of microchannel liquid-cooled plate samples were analysed. The boiling heat transfer experiments were conducted with deionised water, and the boiling heat transfer characteristics were compared with the saturated boiling curve of a traditional copper-tube liquid-cooled plate. The average wall temperature of the designed samples decreased by 4% compared with that of the traditional liquid-cooled plate under the same heat flow density the value reduced from 111.9 °C to 108.2 °C. Furthermore, within the same optimal boiling temperature range, the average heat flow densities of all the prepared samples increased by >60% compared with those of the traditional liquid-cooled plate the value increased from minimum 16 W∙cm−2 to maximum 34 W∙cm−2. The self-supporting microchannel structure can considerably improve the heat dissipation effect of T/R modules and solve the local overheating problem.


2021 ◽  
Vol 12 ◽  
Author(s):  
Haotao Li ◽  
Rongjie Wu ◽  
Haiyang Yu ◽  
Qiujian Zheng ◽  
Yuanfeng Chen

Traditional Chinese medicine (TCM) has demonstrated superior therapeutic effect for musculoskeletal diseases for thousands of years. Recently, the herbal extracts of TCM have received rapid advances in musculoskeletal tissue engineering (MTE). A literature review collecting both English and Chinese references on bioactive herbal extracts of TCM in biomaterial-based approaches was performed. This review provides an up-to-date overview of application of TCMs in the field of MTE, involving regulation of multiple signaling pathways in osteogenesis, angiogenesis, anti-inflammation, and chondrogenesis. Meanwhile, we highlight the potential advantages of TCM, opening the possibility of its extensive application in MTE. Overall, the superiority of traditional Chinese medicine turns it into an attractive candidate for coupling with advanced additive manufacturing technology.


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