Simulation of temp erature field in filling stage of injection molding using thre e2dimensional mo del

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1 6 9 Vol16 No Journal of Chemical Industry and Engineering (China) September 200 1, 2, 1, 1, 2 ( 1, ; 2, 4000) :,,,.. Hele2Shaw,,. Galerkin,,,..,,.. : ; ; ; : TQ : A : (200) Simulation of temp erature field in filling stage of injection molding using thre e2dimensional mo del GENG Tie 1, 2, LI Dequn 1, ZHOU Huamin 1, SHAO Yujie 2 ( 1 S tate Key L aboratory of Mol d & Die Technolog y, H uaz hong Universit y of Science and Technology, W uhan , H ubei, China; 2 Post doctoral Research S tation, A ncai Hi2Tech Co1 L t d, A ny ang 4000, Henan, China) Abstract : The variatio n of t he temperat ure of polymer wo uld have important influence o n t he injectio n molding p rocess. So p redicting exactly t he temperat ure field during filling is very meaningf ul. 3D numerical analysis of temperat ure field in filling stage of injectio n molding is investigated wit h t he F EM met hod. Without t he use of the Hele2Shaw approximation, t he t hree2dimensional theoretical model and numerical scheme for temperature field were established by considering t he influence of convection items in t hree dimensio ns. The energy equatio n was discretized using t he Galerkin met hod. In order to keep numerical stability, the upwind met hod was used to handle t he convection item and viscous heat item. The temperat ure field of t he non2newtonian and nonisothermal fluid wit hin cavities wit h arbitrary t hickness could be p ridicted wit h the model. A wider range of part s was possible and t he prediction result s were better than t he 2D or 21D model. The validity of the model was tested through t he analysis of two cavities. Key words : injectio n molding ; simulatio n ; temperat ure field ; t hree2dimensio n , : (1968 ),,. : ( ) ; ( ). Received date : Corresponding author : GEN G Tie. E - mail : sina1com Foundation item : supported by the Major Program of the National Natural Science Foundation of China ( ).

2 9 : CA E,, [1 ].,,,,,,,., [ 2 ].,.,, Hele2Shaw [3 ]. 1,,,,.,,.,,,.,,.,. Hele2Shaw,.,, [ 46 ] Galerkin..,.,,, : x x 2 u x z w x u z x v x u z w v z x v x u z T cp t = cp K T x v x u 2 w z - p x = 0 (1) 2 v - p = 0 (2) v z w - p z = 0 (3) u x v w z = 0 (4), u T x v T w T z K T z K T z 2 () x y z, u vw x y z, p, T, cp, K,. 2 Fig11 Illustrative finite difference in gapwise direction, Hele2Shaw,.,,., [7 ],,. Cross, Cross, Cross 0 ( T, p) = 1 ( 0 (6) / 3 ) 1 - n

3 , n,, 0.,, 0 Arrhenius [7 ] 0 ( T, p) = Be p e T b / T (7) B Tb, ( n, 3, B, Tb, ). 3 (), Galerkin, N c T V p t dv = x K T x N - c V p u T x v T w T z K T z K T z 2 dv (8), Galerkin,,,, Galerkin,,. [8 ] [9 ],, V^ ( l) i, j = V ( l) i, j DO T > 0 0 DO T 0 DO T, 2, [8 ] (10) (9) DO T = CV (10) C N, V.,, (11) DO T [10 ] 6 DO T = Fl (11) l = 1,,.,, T j Aij - (Bij Cij ) T j = Di (12) t,, Aij Bij Cij Di B^ ij, B^ ij. T j t = Tn 1 j - T n j t t, n n. (14),.. 4 Fig12 Illustrative for judging upriver element of a node 1 3, , 0, 1 s 014 s. ABS780, 1. Fig13 Example cavity T j Aij - (Bij B^ij Cij ) T j = Di (13) t Fig1 4 Meshed cavity

4 9 : 161 Table 1 Material properties Melt density Specific heat / kg m - 3 cp/ J kg - 1 K - 1 N b Thermal conductivity K/ W m - 1 K Cross2type viscosity model B/ Pa s Tb/ K / Pa - 1 Tau/ Pa s, ( a) y = 12;, 01 4 s, (b)., :,,,.,,,.,.,,,,,,, (a) (b), 014 s, x2z ( y = 12) 1 s. 2 6, 6313 mm 4314 mm 2412 mm, 4 mm , 0, 0182 s. ABS780, 1., 8 z = 13..,.,,,,,.,, (),, Hele2Shaw,,,. Fig1 Comparison of temperature distributions on plane y = 12 at same time step between filling time of 1 s and of 014 s

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6 9 : 1617,,,.,,.,,.. Reference s [ 1 ] Manzione L T1 Applacation of Computer2aided Engineering in Injection Molding. Munich : Hanser Publisher, [ 2 ] Li Dequn (). New progress of flow simulation for plastic injection molding. China International Forum on Die &Mould Technology ( ), 2002 () : [ 3 ] Hiebert C A, Shen S F1 A Finite2element/ finite2difference simulation of injection molding filling process. J1 N on2 N ew tonian Flui d Mesh, 1980, 7 : 1 [ 4 ] Prakash C, Patankar S V. A control volume2based finite2 element method for solving the navier2stokes equations using equal2order velocity2pressure interpolation. N umerical Heat T rans f er, 198, 8 : [ ] James G Rice, Rita J Schnipe. An equal2order velocity2 pressure formulation that does not exhibit spurious pressure modes. Com puter Methods in A p plied Mechanics and Engineering, 1986, 8 : [ 6 ] Geng Tie, Dequn Li, Huamin Zhou. Numerical filling simulation of injection molding using t hree2dimensional model. Com puter A i ded D raf ting, Desi gn and M anuf acturing, 2003, 13 (1 2) : 6 14 [ 7 ] Hiebert C A. Ch1 1 in Injection and Compression Molding Fundamentals. Isayev A I, ed. New York : Marcel Dekker, 1987 [ 8 ] Yuan Zhongshuang ( ). Computer simulation and experimental research of the filling and packing stages in plastic injection molding : [ dissertation ] ( ). Wuhan : Huazhong University of Science and Technology, 1993 [ 9 ] Su Mingde (). Basic Computational Fluid Mechanics ( ). Beijing : Tsinghua University Press, [ 10 ] Geng Tie ( ). Three dimensional simulation and experimental research of the filling stage in plastic injection molding : [ dissertation ] ( ). University of Science and Technology, 2003 Wuhan : Huazhong,, 012 %, 2 %3 %,,,,, 7nm, 1/ 100,