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Insights of 3D Printing Technology with Its Types
Published in Harish Kumar Banga, Rajesh Kumar, Parveen Kalra, Rajendra M. Belokar, Additive Manufacturing with Medical Applications, 2023
Ranbir Singh Rooprai, Jaswinder Singh
For solid 3D models, SLS printing uses a laser. Carl Deckard and Joe Beaman coined this term in the 1980s. They later participated in the establishment of the Desktop Manufacturing Corporation (DTM). It was acquired by 3D Systems in 2001. This method is used to manufacture solid objects using metal powder with a high surface finish by layer-by-layer technique [40,41]. An SLS printer is used to print different products with powdered content. In the powder, a laser draws the object’s outline and fuses them. The process is then set up with a new powder sheet, constructing each layer one by one to form the object. It is then repeated. Laser sintering for metal, plastic and ceramic objects may be used. The level of detail is restricted only by laser precision and powder fineness so that it is possible with this type of printer to construct extremely delicate and complex structures [42]. Figure 2.8 shows a view of the SLS technique. SLS technology uses many materials such as composites, stainless steel, thermoplastics and polymers. Because of its high mechanical working capacity, nylon is the best choice for SLS printing [43,44].
Introduction to Additive Manufacturing
Published in Amit Bandyopadhyay, Susmita Bose, Additive Manufacturing, 2019
Amit Bandyopadhyay, Thomas Gualtieri, Bryan Heer, Susmita Bose
While 3D Systems was developing and patenting this technology, other innovators started to develop new types of AM machines that used different methods and materials. At the University of Texas at Austin, an undergraduate student named Carl Deckard and an assistant professor Dr. Joe Beaman started working on a new technology known as selective laser sintering (SLS). SLS worked by first spreading powdered material on a build plate where a laser selectively sintered the powder in certain areas of the plate. Another layer of powder was then distributed over the previous layer and the process was repeated. In the end, the powder from each layer was sintered together in overlapping regions to produce the 3D part. Deckard and Dr. Beaman started working on this technology in 1984 and made the first SLS machine in 1986. They then commercialized the technology, creating the first SLS company called Nova Automation, which later became DTM Corp. In 1989, they made the first commercial machines which were called Mod A and Mod B, and they continued advancing and making more SLS machines until the company was sold to 3D Systems in 2001.4
Optimization of Laser-Based Additive Manufacturing
Published in Linkan Bian, Nima Shamsaei, John M. Usher, Laser-Based Additive Manufacturing of Metal Parts, 2017
Amir M. Aboutaleb, Linkan Bian
Selective Laser Sintering (SLS) is a powder-based AM process in which parts are built by selective sintering of layers of powder using a CO2 laser. SLS can be used to produce functional parts for various applications, such as aerospace and rapid tooling. Shrinkage is a major issue that affects the accuracy of SLS parts. A common practice to resolve the issue of part shrinkage is to calculate or estimate the amount of shrinkage in each direction and apply the shrinkage compensation in the opposite direction in the digital model. Part shrinkage is found to be affected by various process parameters such as laser power, laser velocity, hatch spacing, powder bed temperature, and scanning length. To apply optimal shrinkage compensation to the digital file, it is important to identify the process parameters that govern part shrinkage in each direction, and understand the relation between process parameters and the amount of shrinkage. Raghunath and Pandey (2007) designed experiments using the Taguchi method and used polymer powder to fabricate cuboids of 30 mm × 30 mm cross section with different lengths along the laser scanning direction (i.e., scanning length).
Smart lighting systems: state-of-the-art and potential applications in warehouse order picking
Published in International Journal of Production Research, 2021
Marc Füchtenhans, Eric H. Grosse, Christoph H. Glock
Due to the large number of publications and the broad research interest from many different disciplines, our paper has some limitations. It was not possible, and it was also not our intention, to discuss the strengths and weaknesses of all individual lighting technologies or to look closely at the technical details of the individual systems. Disadvantages were only discussed to a limited extent in this paper, as they mainly consist in investment costs, greater efforts for implementation and overall maintenance requirements due to more complex technologies. However, these disadvantages are negligible on an operational level. Since we present and discuss mainly the potentials of SLS on the operations of warehouse order picking processes, these disadvantages can be seen as a starting point for further research opportunities, for example by analysing the maintenance requirements for different technologies depending on the use case. Given the broad variety of purposes SLS could be used for, it is not easy to estimate the investment cost associated with such systems, or the cost savings resulting from their use. Costs vary from case to case depending on the users’ behaviours, the application scenario and the exact system type used. For example, based on the discussions in the expert workshop, we estimated the return period of a simple SLS for a warehouse with 7500 m2 and an annual lighting duration of 7000 h. Assuming that LEDs, and motion and daylight sensors need to be installed, and considering maintenance costs, a return period between 5 and 6 years was assessed realistic.
Melt-based, solvent-free additive manufacturing of biodegradable polymeric scaffolds with designer microstructures for tailored mechanical/biological properties and clinical applications
Published in Virtual and Physical Prototyping, 2020
Zijie Meng, Jiankang He, Jiaxin Li, Yanwen Su, Dichen Li
SLS has been extensively used for the fabrication of biodegradable tissue engineering scaffolds with controlled architectures (Youssef, Hollister, and Dalton 2017; Bose et al. 2018; Wubneh et al. 2018). During the SLS process (Figure 3(a)), a thin layer of powders is uniformly spread over the building area by a roller, and the laser beam is triggered to scan the powder layer according to the specified cross-section of the CAD model, which results in powders partially melted and fused into a solid pattern. The building platform moved down by one-layer thickness after one layer is completed. The as-defined structure is finally obtained by repeating the powder spreading and laser sintering processes (Meng et al. 2020a). The SLS-fabricated polymeric scaffolds commonly have a feature size larger than 500 μm (Bhushan and Caspers 2017) with relatively rough surface morphology, which is significantly influenced by the powder size as well as the laser spot diameter (Meng et al. 2020a). Since the powders can automatically serve as supporting structures during the laser sintering process, SLS offers benefits in fabricating complex stand-alone architectures including structures with periodic cellular units in comparison with extrusion-based AM techniques (Sudarmadji et al. 2011; An et al. 2015).
Advanced processing of 3D printed biocomposite materials using artificial intelligence
Published in Materials and Manufacturing Processes, 2022
Deepak Verma, Yu Dong, Mohit Sharma, Arun Kumar Chaudhary
SLS is a 3D printing process where the laser is utilized to fuse the polymeric powder particles. As per the design, the laser combines each layer of polymer powders at particular locations. In this process, thermoplastic powders are sintered with the help of the CO2 laser. Similarly, the platform goes down and then provides another layer of powders subjected to further sintering. Some cases show that some of the powders are un-sintered while used to support the product structure. The same powders are then reutilized at the next printing in order to minimize the material wastes .[57]