Wei Zhu, Chunze Yan, Yunsong Shi, Shifeng Wen, Changjun Han, Chao Cai, Jie Liu and Yusheng Shi
Semi-crystalline polymers such as polyamide-12 can be used for selective laser sintering (SLS) to make near-fully dense plastic parts. At present, however, the types of…
Abstract
Purpose
Semi-crystalline polymers such as polyamide-12 can be used for selective laser sintering (SLS) to make near-fully dense plastic parts. At present, however, the types of semi-crystalline polymers suitable for SLS are critically limited. Therefore, the purpose of this paper is to investigate the processibility of a new kind of semi-crystalline polypropylene (PP) with low isotacticity for SLS process.
Design/methodology/approach
The SLS processibility of the PP powder, including particle size and shape, sintering window, degree of crystallinity and degradation temperature, was evaluated. Effects of the applied laser energy density on the surface micromorphology, density, tensile strength and thermal properties of SLS-built PP specimens were studied.
Findings
The results show that the PP powder has a nearly spherical shape, smooth surfaces, an appropriate average particle size of 63.6 μm, a broad sintering window of 21 oC and low crystalline degree of 30.4 per cent comparable to that of polyamide-12, a high degradation temperature of 381.8°C and low part bed temperature of 105°C, indicating a very good SLS processibility. The density and the tensile strength first increase with increasing laser energy density until they reach the maximum values of 0.831 g/cm3 and 19.9 MPa, respectively, at the laser energy density of 0.0458 J/mm2, and then decrease when the applied laser energy density continue to increase owing to the degradation of PP powders. The complex PP components have been manufactured by SLS using the optimum parameters, which are strong enough to be directly used as functional parts.
Originality/value
This paper provides a new knowledge for this field that low-isotacticity PPs exhibit good SLS processibility, therefore increasing material types and broadening the application of SLS technology.
Details
Keywords
Yunsong Shi, Wei Zhu, Chunze Yan, Jinsong Yang and Zhidao Xia
This study aims to report the preparation, selective laser sintering (SLS) processing and properties of a new nylon elastomer powder. The effects of solvent, dissolution…
Abstract
Purpose
This study aims to report the preparation, selective laser sintering (SLS) processing and properties of a new nylon elastomer powder. The effects of solvent, dissolution temperature and time and cooling method and speed on the particle size and morphologies of the prepared nylon elastomer powder are investigated.
Design/methodology/approach
The prepared nylon elastomer power possesses the particle size of around 50 mm and is spherical in shape, indicating that this study provides the feasible dissolution-precipitation process, a distillation cooling method and a suitable solvent to prepare nylon elastomer powders.
Findings
Compared to pure nylon 12, the nylon elastomer has a lower part bed temperature and a wider sintering window for the SLS process. The wider sintering window indicates the better SLS processibility. The lower part bed temperature is beneficial to the recycling of material and the decrease in the requirement of SLS equipment.
Originality/value
The nylon elastomer in this study has a lower part bed temperature and a wider sintering window for the SLS process. The wider sintering window indicates better SLS processibility. The lower part bed temperature is beneficial to the recycling of material and the decrease in the requirement of SLS equipment.
Details
Keywords
Qiuping Yang, Huizhi Li, Yubo Zhai, Xiaofeng Li and Peizhi Zhang
To prepare a new type of composite for selective laser sintering 3D printing, the surface of Al2O3 nanoparticles was modified by the coupling agent…
Abstract
Purpose
To prepare a new type of composite for selective laser sintering 3D printing, the surface of Al2O3 nanoparticles was modified by the coupling agent (3-methacryloxypropyl)-trimethoxy silane (KH570) before coated with thermoplastic epoxy resin (TER).
Design/methodology/approach
Laser diffraction confirmed that the size distribution of prepared powder materials in this study ranged between 20 to 80 µm. Thermogravimetric analysis (TGA) showed that the loading of organic matter was below 5 per cent. Fourier transform infrared spectroscopy indicated that the silane coupling agent molecule bound strongly with the alumina. X-ray diffraction confirmed the prepared powder materials to be α-alumina. Through the angle of repose (AOR) test, the AOR = 18.435º was obtained, suggesting the high flowability of prepared powder materials. Scanning electron microscopy (SEM) observation demonstrated that the shape of the prepared powder materials was sphere-like grains.
Findings
Molding properties of prepared powder materials were studied on the basis of particle size distribution, particle size, sphericity, crystal structure and the reaction mode of the TER. This prepared powder materials can be well applied to the production of epoxy resin-coated Al2O3 composite parts with high precision and good mechanical performance.
Originality/value
This composite can be well applied to the production of epoxy resin-coated Al2O3 composite parts with high precision and good mechanical performance.