Qingwei Liu^1,2, Chunmei Yang^1,2,*, Qian Miao^1,2, Yifan Liu^1,2, Jiuqing Liu^1,*, Wenji Yu³

Journal of Renewable Materials, Vol.8, No.12, pp. 1681-1689, 2020, DOI:10.32604/jrm.2020.012031

Abstract Based on the LOM (Laminated Object Manufacturing) process, an inert gas-assisted laser method for wood cutting was proposed. The carbonization degree of wood surface was improved by the introduction of helium (He) gas, and the influence of process parameters on the carbonization layer of wood surface was solved, it was significance to reduce the post-processing of LOM and improve the quality of forming workpiece. The cherry wood veneer was used as the experimental material, under the condition of the same process parameters, the wood was cut with or without inert gas-assisted, and the influence factors of kerf quality were studied… More >

Qiang Li, Jie Ouyang¹, Xuejuan Li², Guorong Wu², Binxin Yang²

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.3&4, pp. 247-268, 2011, DOI:10.3970/cmes.2011.074.247

Abstract A unified mathematical model is proposed to predict the short shot, primary and secondary gas penetration phenomenon in gas-assisted injection molding (GAIM) process, where the Cross-WLF model and two-domain modified Tait equation are employed to simulate the melt viscosity and density in the whole process, respectively. The governing equations of two-phase flows including gas, air and polymer melt are solved using finite volume method with SIMPLEC technology. At first, two kinds of U-shaped gas channels are modeled, where the shape corner and generous corner cases are studied. At last, as a case study, the short shot, primary and secondary gas… More >

Qiang Li¹, Jie Ouyang¹, Guorong Wu¹, Xiaoyang Xu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.82, No.3&4, pp. 215-232, 2011, DOI:10.32604/cmes.2011.082.215

Abstract The governing equations of two-phase flows including gas and polymer melt are presented, which are solved using finite volume and domain extension methods with SIMPLEC technology. The melt filling and primary gas penetration in gas-assisted injection molding (GAIM) process are simulated, where the Cross-viscosity model is employed to describe the melt rheological behavior, and the CLSVOF(coupled Level Set and Volume of fluid) method is employed to capture the moving interfaces. In order to test and verify the coupled methods, melt filling in a rectangular plate with an insert is simulated, and the numerical results are in good agreement with those… More >

Huamin Zhou¹, Hua Zhang, Dequn Li²

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 209-220, 2009, DOI:10.3970/cmes.2009.046.209

Abstract Gas-assisted injection molding is an innovative process to manufacture hollow polymeric products, in which gas penetration is the primary and key problem. An analytical solution of the gas penetration interface is presented, based on perturbation method. First, the governing equations and boundary conditions are transformed to be dimensionless, where Capillary number Ca is introduced. Then matching asymptotic expansion method is applied to solve these equations, by using Ca and as perturbation parameters to get the inner and outer solutions, respectively. By matching these two solutions, the analytical model of gas penetration is obtained. More >