Different from conventional injection molding (CIM), injection/compression molding (ICM) evolves boundary variation in gapwise direction. In order to describe melt flow characteristics in ICM correctly, a new material derivative based on arbitrary Lagrangian Eulerian (ALE) description was introduced to modify the material derivatives in the governing and constitutive equations. To avoid large amount of calculation and weak stability of integral numerical method, an iterative approach employing twofold iterations was proposed to decouple the interdependence between velocity, stress, and temperature. The initial values of material parameters in constitutive equations were obtained or fitted by rheological experiments. The ICM experiments for an iso-thick and a var-thick rectangular panel were carried out to validate the proposed method and find the special characteristics of ICM. In addition, the photoelastic tests on a quarter of spherical part processed by ICM were conducted to identify the relationship between residual flow-induced stress distributions and flow fields. Both simulations and experiments show that the pressure profile displays a plateau during compression, temperature decreases with time according to exponential law, large flow-induced stress originates in thick transitional region, flow start, and flow end areas, and gravity has significant effect on meltfront for thick part ICM. The good agreement between experiments and simulations indicates that the current method can properly describe the flow characteristics of ICM.

References

1.
Wu
,
C.-H.
, and
Chen
,
W.-S.
,
2006
, “
Injection Molding and Injection Compression Molding of Three-Beam Grating of DVD Pickup Lens
,”
Sens. Actuators A
,
125
(
2
), pp.
367
375
.
2.
Sortino
,
M.
,
Totis
,
G.
, and
Kuljanic
,
E.
,
2014
, “
Comparison of Injection Molding Technologies for the Production of Micro-Optical Devices
,”
Procedia Eng.
,
69
(
1
), pp.
1296
1305
.
3.
Lawal
,
A.
, and
Kalyon
,
D. M.
,
2000
, “
Compressive Squeeze Flow of Generalized Newtonian Fluids With Apparent Wall Slip
,”
Int. Polym. Process.
,
15
(
1
), pp.
63
71
.
4.
Lee
,
S. J.
,
Denn
,
M. M.
,
Crochet
,
M. J.
,
Metzner
,
A. B.
, and
Riggins
,
G. J.
,
1984
, “
Compressive Flow Between Parallel Disks II. Oscillatory Behavior of Viscoelastic Materials Under a Constant Load
,”
J. Non-Newtonian Fluid Mech.
,
14
, pp.
301
325
.
5.
Isayev
,
A. I.
, and
Azari
,
A. D.
,
1986
, “
Viscoelastic Effect in Compression Molding of Elastomers: Shear-Free Squeezing Flow
,”
Rubber Chem. Technol.
,
59
(
5
), pp.
868
882
.
6.
Isayev
,
A. I.
,
Zhang
,
Y.
, and
Zook
,
C.
,
1999
,
Advances in the Flow and Rheology of Non-Newtonian Fluids
,
Elsevier Science
,
Amsterdam, The Netherlands
.
7.
Kim
, I
. H.
,
Park
,
S. J.
,
Chung
,
S. T.
, and
Kwon
,
T. H.
,
1999
, “
Numerical Modeling of Injection/Compression Molding for Center-Gated Disk (Part I: Injection Molding With Viscoelastic Compressible Fluid Model)
,”
Polym. Eng. Sci.
,
39
(
10
), pp.
1930
1942
.
8.
Kim
,
N. H.
,
2009
, “
Injection-Compression and Co-Injection Molding of Amorphous Viscoelastic Simulation and Experiment
,”
Ph.D. dissertation
, University of Akron, Akron, OH.
9.
Wang
,
J. T.
,
1997
,
CAE and Intelligent Processing of Polymeric Materials
,
ASME
,
New York
.
10.
Kim
, I
. H.
,
Park
,
S. J.
,
Chung
,
S. T.
, and
Kwon
,
T. H.
,
1999
, “
Numerical Modeling of Injection/Compression Molding for Center-Gated Disk (Part II: Effect of Compression Stage)
,”
Polym. Eng. Sci.
,
39
(
10
), pp.
1943
1951
.
11.
Lee
,
Y. B.
,
Kwon
,
T. H.
, and
Yoon
,
K.
,
2002
, “
Numerical Prediction of Residual Stresses and Birefringence in Injection/Compression Molded Center-Gated Disk (Part II: Effects of Processing Conditions)
,”
Polym. Eng. Sci.
,
42
(
11
), pp.
2273
2292
.
12.
Chen
,
S.-C.
,
Chen
,
Y.-C.
,
Peng
,
H.-S.
, and
Huang
,
L.-T.
,
2002
, “
Simulation of Injection Compression Molding Process (Part 3: Effect of Process Conditions on Part Birefringence)
,”
Adv. Polym. Technol.
,
21
(
3
), pp.
177
187
.
13.
Chen
,
S. C.
,
Chen
,
Y. C.
, and
Peng
,
H. S.
,
2000
, “
Simulation of Injection-Compression Molding Process (II: Influence of Process Characteristics on Part Shrinkage)
,”
J. Appl. Polym. Sci.
,
75
(
13
), pp.
1640
1654
.
14.
Hu
,
S. T.
,
Chiu
,
H. S.
,
Chien
,
C. C.
,
Yu
,
C. K.
, and
Chang
,
R. Y.
,
2010
, “
True 3D Numerical Simulation in Injection Compression Molding (ICM)
,” SPE ANTEC, Orlando, FL, May 16–20, 2010, SPE ANTEC Technical Paper No. 1, pp.
716
720
.
15.
Li
,
Y.
,
Zhang
,
Y.
, and
Li
,
D.
,
2010
, “
Shrinkage Analysis of Injection-Compression Molding for Transparent Plastic Panel by 3D Simulation
,”
Appl. Mech. Mater.
,
44–47
, pp.
1029
1033
.
16.
Kim
,
N. H.
, and
Isayev
,
A. I.
,
2013
, “
Birefringence in Injection-Compression Molding of Amorphous Polymers: Simulation and Experiment
,”
Polym. Eng. Sci.
,
53
(
8
), pp.
1786
1808
.
17.
Braess
,
H.
, and
Wriggers
,
P.
,
2000
, “
Arbitrary Lagrangian Eulerian Finite Element Analysis of Free Surface Flow
,”
Comput. Methods Appl. Mech. Eng.
,
190
(
1–2
), pp.
95
109
.
18.
Ho
,
J.-Y.
,
Park
,
J. M.
,
Kang
,
T. G.
, and
Park
,
S. J.
,
2012
, “
Three-Dimensional Numerical Analysis of Injection-Compression Molding Process
,”
Polym. Eng. Sci.
,
52
(
4
), pp.
901
911
.
19.
Dwiyantoro
,
B. A.
,
2013
, “
A Numerical Study of an Injection-Compression Molding Process by Using a Moving Grid
,”
Appl. Mech. Mater.
,
249–250
, pp.
472
476
.
20.
Mahmadi
,
K.
, and
Aquelet
,
N.
,
2014
, “
Delayed Mesh Relaxation for Multi-Material ALE Formulation
,”
Int. J. Heat Fluid Flow
,
46
(
4
), pp.
102
111
.
21.
Zatloukal
,
M.
,
2003
, “
Differential Viscoelastic Constitutive Equations for Polymer Melts in Steady Shear and Elongational Flows
,”
J. Non-Newtonian Fluid Mech.
,
113
(
2–3
), pp.
209
227
.
22.
Verbeeten
,
W. M. H.
,
Peters
,
G. W. M.
, and
Baaijens
,
F. P. T.
,
2004
, “
Numerical Simulations of the Planar Contraction Flow for a Polyethylene Melt Using the XPP Model
,”
J. Non-Newtonian Fluid Mech.
,
117
(
117
), pp.
73
84
.
23.
Chang
,
H. H.
,
Hieber
,
C. A.
, and
Wang
,
K. K.
,
1991
, “
A Unified Simulation of the Filling and Postfilling Stages in Injection Molding (Part I: Formulation)
,”
Polym. Eng. Sci.
,
31
(
2
), pp.
116
124
.
24.
Fan
,
Y.
,
Tanner
,
R. I.
, and
Phan-Thien
,
N.
,
1999
, “
Galerkin/Least-Square Finite-Element Methods for Steady Viscoelastic Flows
,”
J. Non-Newtonian Fluid Mech.
,
84
(
84
), pp.
233
256
.
25.
Guénette
,
R.
, and
Fortin
,
M.
,
1995
, “
A New Mixed Finite Element Method for Computing Viscoelastic Flows
,”
J Non-Newtonian Fluid Mech.
,
60
(
1
), pp.
27
52
.
26.
Silva
,
L.
,
Valette
,
R.
,
Laure
,
P.
, and
Coupez
,
T.
,
2012
, “
A New Three-Dimensional Mixed Finite Element for Direct Numerical Simulation of Compressible Viscoelastic Flows With Moving Free Surfaces
,”
Int. J. Mater. Form.
,
5
(
1
), pp.
55
72
.
27.
Hirt
,
C. W.
,
Amsden
,
A. A.
, and
Cook
,
J. L.
,
1997
, “
An Arbitrary Lagrangian–Eulerian Computing Method for All Flow Speeds
,”
J. Comput. Phys.
,
135
(
2
), pp.
203
216
.
28.
Lai
,
H. E.
, and
Wang
,
P. J.
,
2008
, “
Study of Process Parameters on Optical Qualities for Injection-Molded Plastic Lenses
,”
Appl. Opt.
,
47
(
12
), pp.
2017
2027
.
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