Study on selective laser sintering process and investment casting of rice husk/ Co-Polyamide (Co-PA hotmelt adhesive) composite

Abstract

The current available wood-plastic materials used for selective laser sintering (SLS) investment casting are often poor in fluidity in molten state, which is not easy to flow out the shell mold. This led to a large amount of residual ash in mold after heating and lowered the quality of the sintered parts. In this article, the Co-Polyamide (Co-PA Hotmelt adhesive) and rice husk powders (RH) were proposed as the feedstock of the rice husk (RH)/CO-PA composite (RHPA) for SLS. CO-PA with good fluidity was used as the matrix and RH powder as the additive materials. This paper aims to optimize the SLS processing parameters and determine the optimal ratio of RHPA parts manufactured by SLS. Through this work, an orthogonal experimental method of five factors and four levels was used to determine the optimum SLS parameters for the RHPA SLS test. The scan spacing, scan speed, laser power, layer thickness, and preheating temperature are chosen as main SLS affecting factors of this study. The synthesis weighted scoring methods were used to conclude the optimal combination of SLS parameters of RHPA i.e., scan spacing = 0.15mm, scan speed = 2m/s, laser power =16W, layer thickness = 0.25 mm and the preheating temperature = 74°C. Moreover, the influence of RH content on the mechanical properties, dimensional accuracy, and the residual ash content of RHPA parts was determined. When the ratio of RH powder on RHPA is 10 wt %, the bending strength of the sintered parts will reach 2 MPa. Besides, the residual ash content of RHPA parts after heating step was lower (1.1881%) and the tolerance level is CT5. Thus, the dimensional accuracy in X, Y, and Z directions of 10 wt % RHPA SLS parts is 99.79%, 98.71%, and 97.9%, respectively; and the surface of casting was smooth and clear details.

Construction and Compensation of a Dimensional Accuracy Model of a Powder Bed via Laser Sintering

“…(4) If crystalline polymer materials are considered, an additional term for the crystalline shrinkage function must be implemented in a revised model, which is equally valid after fitting the parameters using the experiments described in this paper. (5) The proposed powder bed dimensional accuracy compensation model can be summarized into a process parameter library through a large number of experiments. This parameter library can be used to assist computer software in order to obtain an intelligent process system in order to improve the printing accuracy of the LS equipment.…”

“…Additive manufacturing (AM) is an advanced manufacturing technology that has irreplaceable and unique advantages in contemporary medical, aerospace [ 1 ], and high-end manufacturing industries [ 2 , 3 , 4 , 5 ]. Laser sintering technology (LS), as an additive manufacturing technology [ 6 , 7 , 8 ], has a unique advantage in the forming of polymer materials [ 9 ].…”

Literature Review on the Utilization of Rice Husks: Focus on Application of Materials for Digital Fabrication

“…Polycarbonate and polystyrene powders are the commonly used materials. Although there are not many examples of the utilization of rice husks using this method, a method of fabricating composites for SLS by adding rice husk powder to CO-polyamide powder, which is utilized as a hot melt adhesive, has been proposed [ 20 ]. This study confirmed the effect of rice husk content on the mechanical properties, dimensional accuracy, and residual ash content of parts, as well as the sintering properties of the material, and clarified the requirements for optimizing the SLS 3D printer method for investment casting parts, which are frequently applied in many cases.…”

Influence of Particle Size on the Mechanical Performance and Sintering Quality of Peanut Husk Powder/PES Composites Fabricated through Selective Laser Sintering

“…In the technical process of SLS technology, the powder material particles dissolve and bond to create individual layers, progressively building a solid 3D object [5,6]. Biomass composite powders undergo a sintering process through SLS, where the nearby particles' binder is melted and partially cured by the laser beam's high temperature [6][7][8][9]. SLS technology offers several advantages over other AM methods: (1) cost-effective production of intricate geometric parts without requiring expensive material for SLS use, effectively addressing the material scarcity in SLS technology.…”