To reduce carbon emissions during heating in the manufacturing processes, microwave technology has attracted significant attention. Microwaves have considerable advantages over traditional heating methods, including more rapid heating, lower thermal damage, and eco-friendly processes. To apply microwaves to the manufacturing process, uniform and efficient heating is required. We analyzed the effect of various design parameters for uniform and efficient heating by changing the cavity heights, application of the reflector, and number and positions of waveguides. We conducted a numerical simulation and verified the findings by experiments. The results showed that a slight change in the cavity height altered the electromagnetic field distribution and heating parameters, such as the coefficient of variance and power absorption efficiency. With reflectors installed, 66% of cases exhibited better comprehensive evaluation coefficient (CEC) with consideration of uniform heating and power absorption. The spherical reflector showed 81% of cases, better than those of the ordinary model without a reflector. Furthermore, when double waveguides were installed, the average coefficient of variance (COV) was improved by 22%, and power absorption efficiency was increased by 53% compared to the single waveguide case. When the power applied to the waveguides was doubled, the average COV values improved by 18%. This large-scale analysis will be helpful in applying microwaves to actual industrial sites.

Among the composite manufacturing methods, injection molding has higher time efficiency and improved processability. The production of composites via injection molding requires a pre-process to mix and pelletize the matrix polymer and reinforcement material. Herein, we studied the effect of extrusion process conditions for making pellets on the mechanical and thermal properties provided by injection molding. Polyamide 6 (PA6) was used as the base, and composites were produced by blending carbon fibers and Al₂O₃ as the filler. To determine the optimum blending ratio, the mechanical properties, thermal conductivity, and melt flow index (MI) were measured at various blending ratios. With this optimum blending ratio, pellets were produced by changing the temperature and RPM conditions, which are major process variables during compounding. Samples were fabricated by applying the same injection conditions, and the mechanical strength, MI values, and thermal properties were measured. The mechanical strength increased slightly as the temperature and RPM increased, and the MI and thermal conductivity also increased. The results of this study can be used as a basis for specifying the conditions of the mixing and compounding process such that the desired mechanical and thermal properties are obtained.

Among the various methods used for glass edge sealing, this study uses microwaves to seal glass edges. Through basic experiments, the main process conditions for edge sealing of glass were derived, and the experimental plan and analysis were carried out using the Box-Behnken method of response-surface analysis based on 3 factors and 3 levels. The step height which influences sealing was set as a response variable. If the step height becomes too large, the glass can be damaged, and if the step height is too small, the edge sealing will not be performed. Accordingly, process optimization that edge sealing is possible while minimizing the step height was carried out. A predictable regression equation was derived for the step height of edge sealing and the main-effect analysis was performed for the step height. Using the response-optimization tool, we derived the optimum process condition that minimized the step height of the edge sealing and verified that it matched the error value of 4.1% compared with the target value of the step height measurement result confirmed through the verification experiment.

As automotive lamps are highly integrated, the heat generated from bulbs reduces the light quantity and lifespan of the bulbs. Numerous studies have been actively conducted worldwide on heat dissipation designs and material modifications for heat release. In this study, an analysis was carried out of the mechanical, thermal, and morphological characteristics of Polybutylene Terephthalate (PBT) and Polyamide (PA6) matrix composites containing alumina filler; further, their flowability and injection moldability were also studied. The PA6 matrix that was subjected to an addition of 60% alumina was selected as the sample. To compare the performances of the selected composites with that of the fog lamp reflector manufactured with conventional PBT, fog lamp reflectors were fabricated. When 60% alumina was added, the thermal conductivity was improved. Thus, the maximum temperature of the lamp reflector was reduced, and the heat was transferred to the surroundings; this was in contrast to the fog lamp reflector fabricated with conventional PBT.