This study presents results of Computational fluid dynamics (CFD) analysis conducted to evaluate performances of various functional products developed for smart bathroom systems. The primary objective was to analyze the efficiency of space heating, direct drying, and dehumidification functions in a winter bathroom environment. Representative bathroom models in South Korea were selected and detailed CFD simulations were performed on these models. Results showed that bathtub models exhibited higher efficiency overall in space heating and dehumidification than shower booth models. This was attributed to differences in bathroom structure and internal air flow. Additionally, the direct drying function showed higher efficiency in bathtub models, determined by the placement of air outlets and inlets. This study provides essential foundational data that can contribute to the design and enhancement of smart bathroom systems' functionality, offering valuable insights for the development of optimized smart bathroom products.

Recently, studies of 3D printing methods have been working in various applications. For example, the powder base method laminates the prints by using a binding or laser sintering method. However, the draw back of this method is that the post process is time consuming and does not allow for parts to be rapidly manufactured. The binding method requires the post process while the time required for the post process is longer than the manufacturing time. This paper proposes a UV curing binding method with an integrated piezo printing head system. The optimization of an arbitrary waveform generation for the control of a UV curable resin droplet was researched, in addition to developed optimized UV curing processes in multi nozzle ink jet heads.

Recently, 3D printing technology is a hot issue in various industrial fields. According to the user’s application, it allows for the free form fabrication method to be utilized in a wide range. The powder based fusion technique is one of the 3D printing methods. When using this method it is possible to apply the various binder jetting techniques such as piezo, thermal bubble jet, dispenser and so on. In this paper, a multi thermal bubble ink jet was integrated for jetting of powder binding material and developing a power fused 3D printing system. For high quality 3D printing parts, it needs an analysis and evaluation of the behavior of the thermal bubble ink jet head. In the experiment, a correlation between jetting binder quantity and layer thickness of powder was investigated, and a 3D part model was fabricated, which was used by measuring the scale factor.

Previously fabricated electronic devices were used for vacuum manufacturing processes such as conventional semiconductor manufacturing. However, they are difficult to apply to continuous processes such as roll-to-roll printing, which results in very high device manufacturing and processing costs. Therefore, many developers have been interested in applying continuous processes to contact printing or noncontact printing technologies and they proposed various continuous printing techniques instead of conventional batch coating. In this paper, we proposed improved gravure offset printing process as one of the contact printing technique. We used etching pattern geometry with soft core blanket roll for printing of ultra fine line below the 10um.Using this technique we obtained flexible metal grid mesh film as transparent conductive film.

Transparent conductive films (TCF) with excellent electrical properties and high mechanical flexibility have been widely studied because of their potential for application in optoelectronic devices such as light-emitting diodes, paper displays and organic solar cells. In this paper, we report on low-resistance and high-transparent TCF for flexible device applications. To fabricate a high-resolution roll imprinted TCF, the following steps were performed: the design and manufacture of an electroforming stamp mold, the fabrication of high-resolution roll imprinted on flexible film, the manufacture of Ag-nano paste which was filled into patterned film using a doctor blade process. Also, we was demonstrated with the successful application(ITO free organic photovoltaic) of the developed flexible TCF.

In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem, it is difficult to apply to a continuous process such as a R2R(roll to roll) printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, an electrostatic atomizer sprays micro-drops from the solution injected into the capillary with electrostatic force generated by electric potential of about several tens kV. The organic solar cell based on a P3HT/PCBM active layer and a PEDOT:PSS electron blocking layer prepared from ESD method shows solar-to-electrical conversion efficiency of 1.42% at AM 1.5G 1sun light illumination, while 1.86% efficiency is observed when the ESD deposition of P3HT/PCBM is performed on a spin-coated PEDOT:PSS layer.

Studies are using a roll forming bar. A bar coating device available for a variety of coating conditions was developed. It is characterized by the bar forward and reverse rotation, fine-tune coating speed, and stripe coating. To determine the characteristics of the equipment, the coating tests under different coating conditions were carried out. As a result of the coating tests, the equipment was confirmed as one of strong candidates for the production tool of organic solar cells. The further production test of organic solar cells through stripe coating is in progress.

We report here on the processing and manufacturing of thin film for printed electronics by microgravure coating system. The micro-gravure coating systems are consisted of various modules such as web and system tension controller, micro-gravure coating units, dispenser and hybrid dry units (UV, NIR, Hot air). Especially, for the optimization of system, the number of idle roller was minimized and tension isolating infeeder was included. Also, we applied four patterns circle, 45 degree, square and 35 degree for the optimizing coating thickness. The micro-gravure coating system which applied various patterns to enable continuous coating process and fast coating time compare with conventional batch coating system. In this paper, introduce of micro-gravure coating system and testing results of coating thickness (20~700nm), coating time (1~2sec) and surface roughness (3~12nm) by using micro-gravure coating system.

Nowadays, Three dimensional printing (3DP) technique that is one of solid freeform fabrication (SFF) technology has been notable issue, and has been applied by various fields. The SFF system can fabricate three dimensional objects of solid freeform with high speed and low cost using ink jet printing technology. In this research, a SFF system to analyze 3DP process technology is developed. We applied sliding mode control with sliding perturbation observer (SMCSPO) algorithm and minimized position error to the developed SFF system. We analyzed and optimized process variables such as jetted volume, layer thickness, powder bed and so on experimentally. Also, the dimensional error of a developed SFF system is evaluated. Finally, the feasibility of application to bio manufacturing is presented through successful fabrication of teeth and cranium model.