scholarly journals Additive Manufacturing of a Special-Shaped Energetic Grain and Its Performance

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1509
Author(s):  
Yongjin Chen ◽  
Shuhong Ba ◽  
Hui Ren

In order to solve the problems of the complicated forming process, poor adaptability, low safety, and high cost of special-shaped energetic grains, light-curing 3D printing technology was applied to the forming field of energetic grains, and the feasibility of 3D printing (additive manufacturing) complex special-shaped energetic grains was explored. A photocurable resin was developed. A demonstration formula of a 3D printing energetic slurry composed of 41 wt% ultra-fine ammonium perchlorate (AP), 11 wt% modified aluminum (Al), and 48 wt% photocurable resin was fabricated. The special-shaped energetic grains were successfully 3D printed based on light-curing 3D printing technology. The optimal printing parameters were obtained. The microstructure, density, thermal decomposition, combustion performance, and mechanical properties of the printed grain were characterized. The microstructure of the grain shows that the surface of the grain is smooth, the internal structure is dense, and there are no defects. The average density is 1.606 g·cm−3, and the grain has good uniformity and stability. The thermal decomposition of the grain shows that it can be divided into three stages: endothermic, exothermic, and secondary exothermic, and the Al of the grain has a significant catalytic effect on the thermal decomposition of AP. The combustion performance of the grain shows that a uniform flame with a one-way jet is produced, and the average burning rate is 5.11 mm·s−1. The peak pressure of the sample is 45.917 KPa, and the pressurization rate is 94.874 KPa·s−1. The analysis of the mechanical properties shows that the compressive strength is 9.83 MPa and the tensile strength is 8.78 MPa.

Machines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 84
Author(s):  
Marcin Ziółkowski ◽  
Tomasz Dyl

3D printing conquers new branches of production due to becoming a more reliable and professional method of manufacturing. The benefits of additive manufacturing such as part optimization, weight reduction, and ease of prototyping were factors accelerating the popularity of 3D printing. Additive manufacturing has found its niches, inter alia, in automotive, aerospace and dentistry. Although further research in those branches is still required, in some specific applications, additive manufacturing (AM) can be beneficial. It has been proven that additively manufactured parts have the potential to out perform the conventionally manufactured parts due to their mechanical properties; however, they must be designed for specific 3D printing technology, taking into account its limitations. The maritime industry has a long-standing tradition and is based on old, reliable techniques; therefore it implements new solutions very carefully. Besides, shipbuilding has to face very high classification requirements that force the use of technologies that guarantee repeatability and high quality. This paper provides information about current R&D works in the field of implementing AM in shipbuilding, possible benefits, opportunities and threats of implementation.


Author(s):  
Sagil James ◽  
Thilakraj Shivakumar

Abstract The momentum of the additive manufacturing research is on a spurt. Additive manufacturing, also known as 3D printing process has been attracting the attention of the manufacturing community worldwide over the past decade. The 3D printing technology promises significant advances and applications in the area of automobiles, electronics, and medical devices and so on. However, this technology currently suffers from several limitations including large time consumption, need for support structures and limited range of material selection. This prevents its application in mass production. Holographic 3D printing, also referred to as (volumetric additive manufacturing) process is a very recent technique which uses multiple light beams intensified to form a build volume. A photosensitive liquid resin is solidified using the principle of constructive interference. The single light beam is not enough to produce the required intensity to cure the resin. While the combined interference could generate the required energy. The resulting part is printed in a fraction of seconds at once in contrast with the traditional 3D printing technology. This research studies the feasibility of a novel holographic volumetric additive manufacturing with an ultraviolet source of 365 nm as the primary source of energy. This propels the polymeric photochemical reaction between the monomer molecules. Also, experiments are conducted, incorporating various viscosity levels of the photopolymer material to suppress the oxygen dissolution. At the same time to observe the rate of curing of the photopolymer material. Finally, the mechanical properties of the build volume are analyzed.


RSC Advances ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 5681-5689 ◽  
Author(s):  
Shan Li ◽  
Yubei Zhang ◽  
Tong Zhao ◽  
Weijian Han ◽  
Wenyan Duan ◽  
...  

SiBCN/Si3N4w components with high mechanical properties were manufactured using DLP 3D-printing technology.


2015 ◽  
Vol 6 (2) ◽  
pp. 63-86
Author(s):  
Dipesh Dhital ◽  
Yvonne Ziegler

Additive Manufacturing also known as 3D Printing is a process whereby a real object of virtually any shape can be created layer by layer from a Computer Aided Design (CAD) model. As opposed to the conventional Subtractive Manufacturing that uses cutting, drilling, milling, welding etc., 3D printing is a free-form fabrication process and does not require any of these processes. The 3D printed parts are lighter, require short lead times, less material and reduce environmental footprint of the manufacturing process; and is thus beneficial to the aerospace industry that pursues improvement in aircraft efficiency, fuel saving and reduction in air pollution. Additionally, 3D printing technology allows for creating geometries that would be impossible to make using moulds and the Subtractive Manufacturing of drilling/milling. 3D printing technology also has the potential to re-localize manufacturing as it allows for the production of products at the particular location, as and when required; and eliminates the need for shipping and warehousing of final products.


2021 ◽  
Author(s):  
G.K. Awari ◽  
C.S. Thorat ◽  
Vishwjeet Ambade ◽  
D.P. Kothari

This is a review paper on 3D printing, its significance, and future scope in the aircraft industry.In this article, additive manufacturing is compared with traditional manufacturing in the context of the aircraft industry that gives more accurate knowledge about how additive manufacturing is more effective in terms of cost-cutting, waste prevention, customization, and large-scale production. We will go into the need for 3D printing technology, how it has taken in step over other manufacturing process and are being used for a host of different applications. The paper gives sufficient information about various types of material used in additive manufacturing with the applications, examples, requirements, and process moreover some overview of limitations as well. How Rapid tooling is used with a different process to reduce time and get more productive and efficient parts for the aircraft industries. The use of 3D printing technology in the aircraft industry plays a major role and gained immense applications. It has greatly affected the production line due to its flexibility and ease of production. It is capable of producing intricate parts, a more resilient and lightweight structure that achievesa weight reduction of 40-60%, subsequently result in a leaner cost structure, material saving, and lower fuel consumption.The last section deals with the future scope of additive manufacturing in the aircraft industry with various parameters design aircraft wings, complex design parts, additive manufacturing in space. More companies and the aerospace industry continue to see the value of 3D printing and begin developing on-site 3D printing operations and investing in the technology


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Jiawei Liu ◽  
Haijian Su ◽  
Hongwen Jing ◽  
Chengguo Hu ◽  
Qian Yin

In order to overcome the disadvantage of traditional joint fabrication method—inability to reproduce the rough surfaces of practical rock joints—3D-printing technology was applied to restructure five kinds of rough joint according to the failure surface formed by the triaxial prepeak unloading test in this study. And uniaxial compression test was carried out on the rock-like specimens containing closed 3D-printing rough joint to study the effects of joint inclination and joint length on the mechanical properties (peak strength, peak strain, elastic modulus, and secant modulus), cracking process, and failure modes. Besides, digital image correlation (DIC) method and acoustic emission (AE) system are used to investigate the whole evolution process of strain fields and crack propagation during loading. It is found that the mechanical parameters decrease first and then go up as the joint inclination increases, while presenting a continuous downward trend with the increase of joint length. Inclination of 45° and the larger joint length bring more extensive reduction to mechanical properties of specimens. Specimens exhibit typical brittle failure characteristics. The failure mode of specimens affected by different joint inclination is tension-shear failure. And the joint scale rises; the failure mode of specimens changes from tensile failure to shear failure. Larger joint scale results in the longer prepeak fluctuation phase on axial stress-strain curves and more dispersed distribution of high-value AE counts.


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