Optimization of polyetherimide processing parameters for optical interconnect applications

Polyetherimide (PEI) resin has more excellent characteristics in mechanical, thermal, and electrical and in crack resistance, in comparison with other engineering plastics. Because of this advantage, PEI resin applications have been extending as a material for use in precise mechanical devices and medical equipment.In these applications, different kinds of cleaning should be implemented. Especially, in the area of medical care, the severe cleaning and disinfection by irradiation is repeatedly provided to medical tools after their use to disinfect them from bacteria. It is, therefore, believed that a systematic appreciation of the degradation behavior of PEI resin under various environmental factors is essential. From these view points, we have tried to identify the degradation behavior under such environmental factors as water absorption, ozone water absorption, ultraviolet (UV) ray irradiation, and the coexistence of water absorption and UV ray irradiation, using analytic methods with chemical devices. We also studied how those degradation behaviors influence fatigue characteristics. As a result, it became clear that strength against fatigue was deteriorated by disintegration of the principal chain structure under the coexistent environment of water absorption and UV ray irradiation.

This study optimizes the effect of injection parameters such as melting temperature, injection pressure, injection speed, holding pressure, mold temperature, and cooling time on isotactic polypropylene (iPP) moldings. The 2k factorial design is used to employ for planning the experiment to study the tensile properties of iPP specimens, such as ultimate tensile strength, and strain at yield. The effect of the parameters on the mechanical properties is determined by using the variance analysis. The four factors as melting temperature, holding pressure, mold temperature, and cooling time were the results obtained by screening with a full factorial design, which is a significant parameter. The optimum condition for the highest tensile properties of iPP was obtained when setting injection molding conditions with melting temperature, mold temperature, holding pressure, and cooling time remained at 230 °C, 60 °C, 80 bar, and 20 sec. Base on ANOVA, empirical equations are proposed to relationship for predicting the ultimate tensile strength and strain at yield. The changes in the microstructure of the injection molding specimens are discussed in terms of crystallinity degree. All of this was supported by a polarized optical microscopy (POM) and one-dimension wide-angle X-ray diffraction (1D-WAXD) measurements.

Injection molding technology is known as the most widely used method in mass production of plastic products. To meet the quality requirements, a lot of methods were applied in optimization of injection molding process parameter. In this study the optimization based on Taguchi orthogonal array and Grey relational analysis (GRA) is used to optimize the injection molding process parameters on a LED lens. The four process parameters are: packing pressure, injection speed, melt temperature and mold temperature. The multi-response quality characteristics are total displacement, volumetric shrinkage, and thermal residual stress. The optimal molding parameters are packing pressure (90 MPa), injection speed (300 mm/sec), melt temperature (270 °C) and mold temperature (90 °C). The luminous uniformity of the LED is 92.61 % and the viewing angle of the LED is 124.76°. Among the four factors, packing pressure plays the key role in reducing total displacement, volumetric shrinkage, and thermal residual stress.

As a hot fabrication technology for micro scale parts, micro injection molding is receiving increasing market attention. Improving mechanical properties of micro parts should be an important issue in the micro injection molding process. The relation between weld line strength in micro injection molding parts and processing parameters is investigated. A visual mold with variotherm unit is designed and constructed, in which the micro tensile specimen with weld line are prepared. Polypropylene (PP) is used as the research material in this study, and six processing parameters were chosen as investigating factors, which were melt temperature, mold temperature, injection pressure, packing pressure, ejection temperature and injection speed. In order to achieve optimized processing parameters and their order of significance, Taguchi experiment method was applied in this presented study. The prediction formulation of the strength of micro weld line was built up by multiple regression analysis based on Chebyshev orthogonal polynomial. The results showed the influencing significance order of parameters from strong to week separately are mold temperature, melt temperature, injection speed, ejection temperature, packing pressure and injection pressure. And the tolerance of micro weld line prediction formulation was found to be lower than 21% through confirmation experiments.

Microcellular foam injection molding provides many advantages over conventional foams and their unfoamed counterparts, but its applications are limited by visible surface quality problems such as silver streaks and swirl marks. In this study, we propose a variable mold temperature method to improve the surface quality of molded parts. Electromagnetic induction heating is used in combination with water cooling to achieve rapid mold surface temperature control during the microcellular foam injection molding process. The effect of processing parameters, such as mold temperature, melt temperature, and injection velocity on the part surface quality, was investigated using surface roughness measurements and visual inspection of the molded parts. The results show that using induction heating to increase the mold surface temperature from 100°C to 160°C can decrease surface roughness of polycarbonate moldings from 25 µm to 6.5 µm. It was also found that the flow marks formed by gas bubbles on the part surface can be removed completely at a mold temperature of 160°C. Further increases in the mold temperature show slight improvements in the surface roughness up to 180°C, at which point the surface roughness starts to level off at 5 µm. This surface roughness value reflects an 80% improvement without a significant increase in cycle time over parts molded at a mold temperature of 60°C using water heating. Higher melt temperature and faster injection speed will also improve the surface quality of microcellular injection molded parts but not as significantly. The usefulness of a variable mold temperature in improving part surface quality during microcellular foam injection molding has been successfully demonstrated. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:224–232, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20133

One of the main challenges in the automotive industry is the development of lightweight components reducing energy consumption and emissions during production and use. For this purpose, material selection and the production process must be optimized. Lightweight, high‐performance materials such as long fiber thermoplastics (LFT) and lightweight technologies such as foam injection molding (FIM) are therefore ideal for achieving high weight reductions through adapted component designs. With the foam injection molding technology ProFoam, it is possible to achieve longer fibers in the component with long‐fiber thermoplastics and thus the weight‐specific properties can be improved. To analyze the potential of the foam injection molding process for the design freedom of lightweight components, plates with ribs are manufactured using injection molding and foam injection molding with a 10 % weight reduction. The process parameters injection speed, melt and mold temperature and the rib geometries are analyzed in this contribution. During foam injection molding process, it is found that cell formation and fiber length are significantly affected by melt temperature and injection speed, which influence further the mechanical properties

The rapid advancement of optoelectronic devices has intensified the demand for materials that are not only functional but also mechanically adaptable to human-centric applications. Conventional transparent conductors, such as indium tin oxide, offer excellent conductivity and optical transparency but fail under mechanical strain, limiting their use in flexible and stretchable systems. This limitation has motivated the development of intrinsically stretchable and transparent conductors capable of maintaining electrical and optical performance under large, repeated deformations. These conductors are typically fabricated by embedding conducting fillers within elastomeric matrices, providing skin-like mechanical compliance without the need for complex geometric patterning and enabling seamless integration with soft, irregular surfaces. Intrinsically stretchable and transparent conductors can be divided into metallic and non-metallic conductors. Each category offers distinct advantages but also presents trade-offs among conductivity, transparency, stretchability, and environmental stability. Therefore, careful material selection and design optimization are essential to balance these competing properties. This review summarizes recent progress in intrinsically stretchable and transparent conductors, with a focus on materials and design strategies for optimizing electrical, optical, and mechanical performance. We further highlight their integration into optoelectronic devices and discuss remaining challenges and potential solutions to advance next-generation soft optoelectronic technologies.

Analysis of the injection‐molding process based on Leonov viscoelastic fluid model has been employed to study the effects of process conditions on the residual stress and birefringence development in injection‐molded parts during the entire molding process. An integrated formulation was derived and numerically implemented to solve the nonisothermal, compressible, and viscoelastic nature of polymer melt flow. Simulations under process conditions of different melt temperatures, mold temperatures, filling speeds, and packing pressures are performed to predict the birefringence variation in both gapwise and planar direction. It has been found that melt temperature and the associated frozen layer thickness are the dominant factors that determine the birefringence development within the molded part. For a higher mold temperature, melt temperature, and injection speed, the averaged birefringence along gapwise direction is lower. The birefringence also increases significantly with the increased packing pressure especially along gate area. The simulated results show good consistency with those measured experimentally. © 1995 John Wiley & Sons, Inc.

This paper presents an application of the Continuous Sensitivity Equation Method (CSEM) for the optimization of the injection molding process and its three-dimensional (3D) simulation by the finite element method. Finding the proper combination of process parameters such as injection speed, and melt and mold temperatures is critical to achieving a part that minimizes warpage and has the desired mechanical properties. Very often a successful design in injection molding comes at the end of a long trial and error process. Design Sensitivity Analysis (DSA) can help manufacturers improve their designs and can produce substantial savings in terms of both time and money. This work explores the ability of sensitivity analysis to predict the effects of design parameters on the performance of an injection molding process. The paper presents results of a 3D finite element solution of the filling stage of the injection molding process. Sensitivities of the solution with respect to different process parameters are computed using the continuous sensitivity equation method. Solutions are shown for the non-isothermal filling of a rectangular plate with a polymer melt behaving as a non-Newtonian fluid. The paper presents the equations for the sensitivity of the velocity, pressure and temperature and their solution by a finite element method. Sensitivities of the solution with respect to the injection speed, the melt and mold temperatures and to the heat transfer coefficient at the cavity/mold interface are shown.

Fabrication and optical property improvement of gasochromic switchable mirror based on Pd/Mg[sbnd]Nb2O5 thin film

A fast and effective methodology integrating the finite-element and Taguchi methods is presented to determine the optimal design conditions of the injection molding process for short-fiber-reinforced polycarbonate composites. The finite-element-based flow simulation software, M-flow, was employed to simulate the molding process to obtain the fiber orientation distributions required. The Taguchi optimization technique was used to identify the optimal settings of injection molding parameters to maximize the shear layer thickness. The effects of four main parameters — the filling time, melt temperature, mold temperature, and injection speed — on the fiber orientation or the shear layer thickness were investigated and discussed. It is found that the dominant parameter is the filling time. The best levels of the four parameters to acquire the thickest shear layer are also identified.

Injection molding is now used to mold plastic parts with precision contours such as lenses. Cooling conditions have critical effects on the quality and productivity of such precision parts. This article is devoted to investigate the effects of mold temperature and cooling time on quality. A two-cavity mold for molding convex lenses with square-looped cooling channels was used. Samples molded with different mold temperatures and cooling times were collected, and their contour conformity to those of the cavity was evaluated. Contour errors were defined. The correlation between mold temperature and cooling time and contour errors was analyzed. It has been found that for a given mold temperature, two critical cooling times can be defined at which the thermal and rigidity states pass through a transition. Most dramatic improvements in part conformity occur around such critical points. © 1996 John Wiley & Sons, Inc.

In this study, the effect of injection parameters on sink marks and photometric properties in the production of reflector used in automobiles was investigated. Mold filling analysis was performed with Moldflow software and sinkmarks and warpage were determined before production. Afterwards, the reflector was produced. The effects of injection parameters such as melt temperature, mold temperature, injection speed, injection pressure, holding time and cooling time on sink marks and photometry were investigated by Taguchi and Anova analysis. In the mold filling simulation, a sink mark of 0.05 mm was formed, while an average of 0.053 mm of sink mark was formed in the experimental results. It was found that the most effective parameter on the sink mark was melt temperature, while cooling time was found for photometry. In the experiment, the lowest sink marks value was 0.053 mm in avarage, and the highest photometry value (923.33 mcd/lux) was measured in the same test. The lowest photometry value was measured as 700.33 mcd/lux and the sink marks value in this experiment was 0.082 mm. The sink marks on the reflector surface change the illumination angles by disrupting the surface planarity, and the reflector’s reflective properties are also affected by this.

Homogeneous organic–inorganic hybrid materials with excellent thermal and optical performance were successfully prepared via the mixing of (3‐methacryloxypropyl)trimethoxysilane‐capped acrylic resin with titania synthesized by sol–gel approaches. The effects of the titania content, amount of water, and pH in the sol–gel and the ratio of the solvents (butyl acetate and ethanol) on the structures and properties of the hybrid materials were studied. More titania, more water, and base catalysis in the sol–gel process and a higher ratio of butyl acetate to ethanol for the hybrids led to a larger size and a more compact structure of the titania phase. Increasing the titania content dramatically improved the glass‐transition temperature, UV‐shielding properties, and refractive index for the hybrid materials, and it did not reduce their optical transparency. In general, better thermal stability and optical properties were achieved for the hybrid materials prepared with less water, lower pH values (e.g., acidic or neutral conditions), and a lower ratio of butyl acetate to ethanol. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 637–649, 2005

Article Effects of Injection Molding Processing Parameters on the Appearance Related Optical Properties of Polycarbonate was published on October 1, 2006 in the journal Journal of Polymer Engineering (volume 26, issue 7).