A cost-effective method for rapid manufacturing polymer rapid tools used for liquid silicone rubber injection molding

Kuo, Chil-Chyuan; Lin, Jianming

doi:10.1007/s00170-019-04000-w

Cited by 12 publications

(8 citation statements)

References 50 publications

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“…Generally, both CHCs and CCCs are a complex heat transfer problem with transient conditions. To prevent the over-curing of the LSR during LSR injection molding [ 6 , 7 ], five curing temperatures were used in this study. First of all, a vulcanizing hot-water temperature of 60 °C was employed to investigate the curing time [ 24 , 25 ] of the molding product.…”

Section: Resultsmentioning

confidence: 99%

“…Generally, the more uniform the mold temperature, the shorter the cross-linking time of LSR. According to practical experience in the fabrication of LSR parts using injection molding [ 6 , 7 ], one major drawback is that the uniformity of the vulcanization temperature of LSR can be improved when a cartridge heater [ 8 ] is incorporated in the conventional mold steel. Thus, improving the uniformity of the vulcanization temperature of LSR is an important research issue.…”

Section: Introductionmentioning

confidence: 99%

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Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

Kuo

Tasi

Hunag³

2022

Polymers

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Liquid silicone rubber (LSR) parts have some distinct characteristics such as superior heat stability, low-temperature flexibility, aging resistance, and chemical resistance. From an industrial standpoint, the uniform vulcanization temperature of LSR is an important research point. However, the uniformity of the vulcanization temperature of LSR has been limited since the layout of the cartridge heater incorporated in the conventional steel mold does not follow the profile of the mold cavity. Metal additive manufacturing can be used to make LSR injection molds with conformal heating channels and conformal cooling channels simultaneously. However, this method is not suitable for a mold required to develop a new LSR product. In this study, a cost-effective approach was proposed to manufacture an LSR injection mold for the pilot run of a new optical lens. A rapid tool with low vulcanization energy consumption channels was proposed, which was incorporated with both a conformal heating channel (CHC) and conformal cooling channel (CCC) simultaneously. The function of the CHC was to vulcanize the LSR in the cavity uniformly, resulting in a shorter cycle time. The function of the CCC was to keep the LSR in a liquid state for reducing runner waste. It was found that the equation of y = −0.006x3 + 1.2114x2 − 83.221x + 1998.2 with the correlation coefficient of 0.9883 seemed to be an optimum trend equation for predicting the solidification time of a convex lens (y) using the vulcanizing hot water temperature (x). Additionally, the equation of y = −0.002x3 + 0.1329x2 − 1.0857x + 25.4 with the correlation coefficient of 0.9997 seemed to be an optimum prediction equation for the solidification time of a convex lens (y) using the LSR weight (x) since it had the highest correlation coefficient. The solidification time of a convex lens could be reduced by about 28% when a vulcanizing hot water temperature of 70 °C was used in the LSR injection mold with CHC.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

Kuo

Tasi

Hunag³

2022

Polymers

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“…Thus, further works are required to optimize the layout of the CCCs using the simulation software. The mechanical properties of SRM are inferior to that fabricated by aluminum (Al)-filled epoxy resins [ 58 , 59 , 60 , 61 ]. Therefore, the Al-filled epoxy resins can be used to make an injection molding tool with CCC for batch production of wax patterns.…”

Section: Resultsmentioning

confidence: 99%

Improving Cooling Performance of Injection Molding Tool with Conformal Cooling Channel by Adding Hybrid Fillers

Kuo

2021

Polymers

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Silicone rubber mold (SRM) is capable of reducing the cost and time in a new product development phase and has many applications for the pilot runs. Unfortunately, the SRM after injection molding has a poor cooling efficiency due to its low thermal conductivity. To improve the cooling efficiency, the thermal conductivity of the SRM was improved by adding fillers into the SRM. An optimal recipe for fabricating a high cooling efficiency low-pressure injection mold with conformal cooling channel fabricated by fused deposition modeling technology was proposed and implemented. This study proposes a recipe combining 52.6 wt.% aluminum powder, 5.3 wt.% graphite powder, and 42.1 wt.% liquid silicon rubber can be used to make SRM with excellent cooling efficiency. The price–performance ratio of this SRM made by the proposed recipe is around 55. The thermal conductivity of the SRM made by the proposed recipe can be increased by up to 77.6% compared with convention SRM. In addition, the actual cooling time of the injection molded product can be shortened up to 69.1% compared with the conventional SRM. The actual cooling time obtained by the experiment is in good agreement with the simulation results with the relative error rate about 20%.

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“…ζ is an adjustment coefficient, ζ can be calculated by substituting the without ultrasonic vibration actual test yield stress (σ yt ) and χ c into Equation (8). For the numerical relationship between the strength and the hardness corresponding to Equation (4), where the injection temperature is 200 C, 220 C, and 240 C, the ζ is 0.512, 0.544, and 0.463, respectively. According to the χ c of the specimen under different ultrasonic vibration time, the σ yc under different ultrasonic vibration time are obtained by Equation ( 8) and the σ yt , as shown in Figure 7A.…”

Section: Relationship Between Yield Stress and Crystallinitymentioning

confidence: 99%

“…In this regard, scholars had carried out a lot of fruitful research work by improving material properties, optimizing molding process conditions, and applying different assisted-external fields. [1][2][3][4] In recent years, ultrasonic vibration as an assisted external field in injection molding has attracted much attention, [5] mainly reflected in the melt plasticizing, [6] filling, and cooling stages. [7,8] With regard to the effect of ultrasonic vibration on the polymer plasticization, Isayev [6] found that the ultrasonic vibration reduced the viscosity of the melt during the polymer plasticization progress and the injection pressure during the subsequent melt filling progress.…”

Section: Introductionmentioning

confidence: 99%

Effect of ultrasonic vibration time on the molecular stacking structure and mechanical properties of the injection molding workpiece

Zou

Duan

2022

Polymer Engineering & Sci

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To study the effect of the high‐frequency vibration time on the mechanical properties of the injection molding workpieces, apply an improved ultrasonic vibrator which contains the original ultrasonic vibrator and the mold insert to change the crystal structure during the melt cooling stage. The crystallinity, crystal perfection, and yield stress characteristics of the workpieces under three injection temperatures were compared with those without ultrasonic vibration. Results manifested that the change of the yield stress and cross‐section crystallinity of the sample obeys the Gaussian distribution at a specific ultrasonic vibration time. The maximum yield strength and the maximum change of the workpiece were 39.06 MPa (220°C, 8 s) and 12.70% (240°C, 10 s), respectively. With the ultrasonic vibration time increased, the crystallinity of the specimen surface decreased; the transition layer and crystal perfection increased first and then decreased. Therefore, considering the relationship between the ultrasonic vibration time and the yield stress, the vibration effect played a critical role at the initial stage of the ultrasonic vibration; the vibration induced the thermodynamics effect required a certain vibration time. This study contributed to changing the mechanism of crystal structure and yield stress under different ultrasonic vibration time.

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A cost-effective method for rapid manufacturing polymer rapid tools used for liquid silicone rubber injection molding

Cited by 12 publications

References 50 publications

Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

Improving Cooling Performance of Injection Molding Tool with Conformal Cooling Channel by Adding Hybrid Fillers

Effect of ultrasonic vibration time on the molecular stacking structure and mechanical properties of the injection molding workpiece

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