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Overview of 3D-printing Technology
Published in Harish Kumar Banga, Rajesh Kumar, Parveen Kalra, Rajendra M. Belokar, Additive Manufacturing with Medical Applications, 2023
Spencer et al. [116] used two post-processing techniques (vibratory bowl abrasion finishing) on parts made from XB 5143 (general purpose resin) and Ciba-Geigy XB5081-1 (durable resin) to enhance surface roughness. The results of SEM and surface topography showed that both the post-processing method can enhance the surface finish of a model. However, the vibratory bowl abrasion finishing process has gained a superior surface finish which is about 74 per cent improvement over ultrasonic abrasion finishing. Schmid et al. [117] refined the selective laser sintering (SLS) parts using vibratory grinding and reduced Ra value from 11 to 2μm. Pandey et al. [118] improved the surface roughness of the parts built by the FDM process using hot cutter machining. It was found that surface roughness of 0.3 μm has 87 % confidence levels. However, this technique is restricted to flat surfaces. Various researchers [119–121] used different lasers to improve surface finish. However, carbon dioxide laser is most commonly used for industrial applications (marking, drilling, cutting, engraving, annealing and heat treatment of industrial materials) owing to its high efficiency and rugged construction. However, among distinct post-processing techniques, laser micromachining is the most widely used method [122]. From the results of various researchers, it is clear that the surface finish of the additive manufacturing parts can be significantly enhanced by utilising distinct post-processing methods.
Lasers in Medicine: Healing with Light
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
Infrared lasers such as the Nd:YAG and carbon dioxide lasers offer high powers and are popular choices for general purpose photovaporization. The Nd:YAG operating in the infrared at 1064 nm is not absorbed strongly by blood, water, or tissue (Figure 3.26). However, it still transfers energy effectively to most tissues through strong scattering, a process that is not as specifically dependent on wavelength. The carbon dioxide laser also operates in the infrared at a wavelength of 10,600 nm. Unlike visible light, this wavelength is strongly absorbed by water. In fact, over 99% of the beam is absorbed within 50 microns of water. This makes the carbon dioxide laser a general purpose laser for many procedures where no pigment is available to selectively absorb the laser light. The infrared light of the erbium:YAG is both powerful and strongly absorbed. Because its wavelength is shorter than the carbon dioxide laser, it can be focused down to smaller spot sizes, allowing it to drill bone and dental enamel.
Common Lasers and Parameters
Published in Mark Steven Csele, Laser Modeling, 2017
The carbon dioxide laser is commonly used for industrial processing and cutting applications. The mid-IR wavelength of 10.6μm is absorbed readily by most plastics but is not altogether optimal for cutting many metals. However, the cost per watt rivals that of many other types of lasers.
A hybrid model compression approach via knowledge distillation for predicting energy consumption in additive manufacturing
Published in International Journal of Production Research, 2023
Yixin Li, Fu Hu, Ying Liu, Michael Ryan, Ray Wang
An SLS process involves the application of a carbon dioxide laser beam to a powder to sinter or fuse it. A temperature of almost the melting point of the material is maintained in the chamber. For each layer specified by the design, the powder was fused using a laser at a specific location. When a layer is completed, a piston lowers the layer thickness by the same amount every time a layer is completed (Wong and Hernandez 2012; Gao et al. 2015). In this case study, an SLS machine (EOS P700) was used to fabricate the product. With a building envelope measuring 740 mm by 400 mm by 590 mm (x, y, and z), two CO2 lasers can sinter nylon materials (PA2200 and PA3200GF) on the EOS P700. The original polyamide-12 is PA2200, and PA3200GF contains 40% glass beads to increase stiffness (Qin, Liu, and Grosvenor 2018). The material used in this experimental study is PA2200.
Interaction of obliquely incident lasers with anharmonic CNTs acting as dipole antenna to generate resonant THz radiation
Published in Waves in Random and Complex Media, 2022
Sandeep Kumar, Shivani Vij, Niti Kant, Vishal Thakur
The following parameters of laser, plasma, and CNTs have been employed by us to carry out numerical calculations. The angular frequencies of carbon dioxide laser beams are and Analogous to these angular frequencies, wavelengths of laser beams are and . Both the laser beams have intensities of the order . The laser spot size of each beam is . The length of each CNT in the array is . The inner and outer radii of each CNT are , and respectively. The relative permittivity of the glass substrate is . The plasma frequency of CNTs and angle of incidence .
Synergistic fabrication of micro-nano bioactive ceramic-optimized polymer scaffolds for bone tissue engineering by in situ hydrothermal deposition and selective laser sintering
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Yong Xu, Wenhao Ding, MeiGui Chen, Haochen Du, Tian Qin
For scaffold fabrication, the mixed powder prepared above was introduced into the SLS system. The system includes a carbon dioxide laser with a wavelength of 10.64 μm and a galvanometer system and is also equipped with a simple automatic powder supply device. First, the STL file that implicitly contains the information of three-dimensional scaffold was imported into the laser sintering software system. Subsequently, slice and layer processing was performed, and the thickness of a single processing layer was set. In the continuous processing mode, the laser beam selectively scans the powder according to the contour of single slice layer. The high-energy laser melts and rapidly solidifies the scanned powder, and a three-dimensional scaffold was prepared via stacking layer by layer. The processing parameters in the scaffold preparation process were constant as laser power 5.4 W, laser rate 350 mm/s, powder layer thickness 0.15 mm, scanning spacing 0.40 mm, and cross-filling method was adopted. After sintering, clean compressed air was used to remove unsintered powder. A scaffold prepared by SLS had an interconnected porous structure, as shown in Figure 1.