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. 2023 Jun 29;15(13):2869.
doi: 10.3390/polym15132869.

Development of an Injection Mold with High Energy Efficiency of Vulcanization for Liquid Silicone Rubber Injection Molding of the Fisheye Optical Lens

Chil-Chyuan Kuo  1   2   3 , Qing-Zhou Tasi  1 , Song-Hua Hunag  4 , Shih-Feng Tseng  5
Affiliations

Development of an Injection Mold with High Energy Efficiency of Vulcanization for Liquid Silicone Rubber Injection Molding of the Fisheye Optical Lens

Chil-Chyuan Kuo et al. Polymers (Basel). .

Abstract

Liquid silicone rubber (LSR) techniques are experiencing exponential growth, particularly in the field of high technology due to the low-temperature flexibility, superior heat stability, chemical resistance, and aging resistance of LSR components. Enhancing the curing rate of LSR parts in liquid silicone rubber injection molding is an important research topic. In this study, an injection mold with high energy efficiency of vulcanization for the liquid silicone rubber injection molding of a fisheye lens was developed and implemented. The LSR injection mold has a conformal heating channel (CHC) and conformal cooling channel (CCC) simultaneously. The function of CHC is to enhance the curing rate of a fisheye lens in the LSR injection molding to meet the requirements of sustainable manufacturing. The curing rates of a fisheye lens were numerically examined using the Moldex3D molding simulation software. It was found that the curing rate of the fisheye optical lens cured by injection mold with CHC was better than that of the injection mold with a conventional heating channel. The curing efficiency could be increased by about 19.12% when the heating oil temperature of 180 °C was used to cure the fisheye optical lens. The simulation results showed that the equation y = -0.0026x3 + 1.3483x2 - 232.11x + 13,770 was the most suitable equation for predicting the curing time (y) through the heating oil temperature (x). It was found that the trend of the experimental results was consistent with the simulation results. In addition, the equation y = -0.0656x2 + 1.5827x - 0.894 with the correlation coefficient of 0.9974 was the most suitable equation for predicting the volumetric shrinkage of the fisheye optical lens (y) through the heating oil temperature (x). The volume shrinkage of the fisheye optical lens cured by injection mold with CHC was very similar to that of the injection mold with a conventional heating channel. The maximum volume shrinkage of the fisheye optical lens cured at 180 °C was about 8.5%.

Keywords: conformal cooling channel; conformal heating channel; curing rate; energy efficiency; liquid silicone rubber; sustainable manufacturing.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Flowchart of this study.
Figure 2
Figure 2
3D CAD model and dimensions of (a) CCC and (b) CHC.
Figure 3
Figure 3
CAD models of cavity insert with CHC and core insert with CCC.
Figure 4
Figure 4
Schematic illustration of LSR injection mold with CHC and CCC for LIM.
Figure 5
Figure 5
Mesh of the simulation models used in this study.
Figure 6
Figure 6
Material properties of LSR used in this study: (a) viscosity chart and (b) pressure–volume–temperature diagram.
Figure 7
Figure 7
Manufacturing processes of LSR injection mold.
Figure 8
Figure 8
Experimental setup for LSR injection molding.
Figure 9
Figure 9
LSR injection mold.
Figure 10
Figure 10
Mold temperature distribution of LSR injection mold with conventional heating channel using nine different heating oil temperatures.
Figure 11
Figure 11
Mold temperature distribution of LSR injection mold with CHC using nine different heating oil temperatures.
Figure 12
Figure 12
Dependence of the mold temperature on the different heating oil temperature for the LSR injection mold with (a) conventional heating channel and (b) CHC using nine different heating oil temperatures.
Figure 13
Figure 13
Numerical simulation results of the curing rate of the fisheye optical lens as a function of curing time for LSR injection mold with conventional heating channel using different heating oil temperatures.
Figure 14
Figure 14
Numerical simulation results of the curing rate of the fisheye optical lens as a function of curing time for LSR injection mold with CHC using different heating oil temperatures.
Figure 15
Figure 15
Numerical simulation results of the evolution of the curing rate of the fisheye optical lens using heating oil temperature of 180 °C.
Figure 16
Figure 16
Dependence of the heating oil temperature and curing time of the fisheye optical lens.
Figure 17
Figure 17
Schematic illustration of heat transfer of LSR injection mold with heating oil channel.
Figure 18
Figure 18
Numerical simulation results of volumetric shrinkage of the fisheye optical lens for the LSR injection mold with CHC using nine different heating oil temperatures.
Figure 19
Figure 19
Experimental and numerical simulation results of curing time of fisheye lens for LSR injection mold with conventional heating channel.
Figure 20
Figure 20
Experimental and numerical simulation results of curing time of fisheye lens for LSR injection mold with CHC.
Figure 21
Figure 21
Numerical simulation results of the volume shrinkage of the fisheye optical lens for LSR injection mold with CHC under the curing temperature at (a) 60 °C, (b) 80 °C, (c) 100 °C, (d) 120 °C, (e) 140 °C, (f) 150 °C, (g) 160 °C, (h) 170 °C, and (i) 180 °C.
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