Roll-to-Roll printing process has become a great issue as a breakthrough for low cost and mass production of electronic devices such as organic thin film transistor, and etc. To print the electronic devices, multi-layer printing is essential, and high precision register control is required for this process. Unlike stop-and-repeat printing process, it is impossible to control the register in a static state since the roll-to-roll process is a continuous system. Therefore, the behavior of web such as polyethylene terephthalate (PET) and polyimide (PI) by the tensile and thermal stress generated in the roll-to-roll process as well as motor control of driven rolls has to be considered for a high precision register control. In this study, the correlation between curing temperature and thermal deformation of PET web is analyzed. Finally, it is verified experimentally that the temperature disturbance generates the more serious register error under the higher curing temperature.

Manufacturing processes of industrial tire are composed of mixing, extrusion, curing, trimming and inspecting. Among them curing is the most important process in the production of industrial tire. In this study the newly developed spring vent system was designed in order to solve rubber intrusion problem inside spring vent system in the curing process. After the experiment it is concluded that rubber intrusion was caused by angled stem head part. New spring vent system was manufactured and new design of spring vent system is proper to use for industrial tire curing process.

In this paper, characteristics of a tidal current power generation system are analysis using power hardware-in-the-loop simulation (PHILS). A 10 kW motor generator set is connected to the real grid through a fabricated 10 kW back to back converter. A power control scheme is applied to the back to back converter. A 2 MW class tidal current turbine is modeled in real time digital simulator (RTDS). Generating voltage and current from the 10 kW PMSG is applied to a 2 MW class tidal current turbine in the RTDS using PHILS. The PHILS results depict the rotation speed, power coefficient, pitch angle, tip-speed ratio, and output power of tidal current turbine. The PHILS results in this paper can contribute to the increasing reliability and stability of the tidal current turbines connected to the grid using PHILS.

Nozzle ring is an important part of turbocharger which is applied to today"s most diesel engines. Turbo charger nozzle ring is difficult to process and takes a high cost and a long time relatively. For this reason, it is largely produced by using a precision casting. Investment method, the representative technology of precision casting, has excellent dimensional accuracy and can produce complex shapes relatively easily. However, it is difficult to avoid the casting defects such as shrinkage cavity and short shot. This study is to predict the casting defects which could be occurred during the investment method by use of finite element analysis software and to design the process and mold of the marine turbocharger nozzle ring.

One of the most important element technologies for achieving high-precision in machine tool spindle systems is preload technology for the bearing of spindle systems. Fixed position preload, constant pressure preload, conversion preload and variable preload methods have been applied for the spindle systems. In this study, a new variable preload method using centrifugal force and rubber pressure is used for reducing installation costs through simplifying its structure. The main objective of the work is the verification of the operability in a preload device using the rubber pressure by the finite element analysis. It is shown that the variable preload device proposed in this study is applicable to high speed machine tool spindles.

This paper presents a high-performance flexible tactile sensor based on inorganic silicon flexible electronics. We created 100 nm-thick semiconducting silicon ribbons equally distributed with 1mm spacing and 8×8 arrays to sense the pressure distribution with high-sensitivity and repeatability. The organic silicon rubber substrate was used as a spring material to achieve both of mechanical flexibility and robustness. A thin copper layer was deposited and patterned on top of the pressure sensing layer to create a flexible temperature sensing layer. The fabricated tactile sensor was tested through a series of experiments. The results showed that the tactile sensor is capable of measuring pressure and temperature simultaneously and independently with high precision.

This paper presents a scheduling problem for a high-density robotic workcell using multi-objective genetic algorithm. We propose a new algorithm based on NSGA-II(Non-dominated Sorting Algorithm-II) which is the most popular algorithm to solve multi-objective optimization problems. To solve the problem efficiently, the proposed algorithm divides the problem into two processes: clustering and scheduling. In clustering process, we focus on multi-robot positions because they are fixed in manufacturing system and have a great effect on task distribution. We test the algorithm by changing multi-robot positions and compare it to previous work. Test results shows that the proposed algorithm is effective under various conditions.

This paper is study of solving vibration problem occurred in moving hand of wafer transfer robot in semiconductor manufacturing line. Long settling time for decreasing vibration makes low production rate, and moreover the excessive vibration of hand sometimes breaks the wafer in a cassette. The ways of reducing the moving speed and changing the type of motion profile did not help for lessening vibration. Therefore, we analyzed the mechanical property of the hand such as natural frequency, and frequency component of the motion profile currently used in the manufacturing line. In several conditions of motion profile, we found the best condition of which the frequency component in near of natural frequency of the hand is minimal and this induced small vibration in moving hand. The results were verified theoretically and experimentally using frequency analysis.

In this paper, we propose a novel velocity ripple controller using phase compensation feedforward control. Velocity ripples result in many kinds of performance degradations in manufacturing machines, especially such as ultra-precision roll lathes. The generation of velocity ripple in constant velocity control comes from various causes, such as electrical torque ripples, mechanical worn out, inconsistent mass center, etc. Conventional researches about ripple is mainly for reducing torque ripple in actuator level, which is only one of reasons for velocity ripples, so in this study, we focus on eliminating velocity ripples in upper level controller using phase compensation feedforward controller. The proposed algorithm is composed of several modules, such as ripple extractor, phase adjuster and phase follower etc. The suggested algorithm can be easily extended, and it shows a superior performance in the experiments of ultra-precision roll lathes.

Recently, surface texturing technologies have been widely used in lots of industries to increase the machinery efficiency. In this research, the lubrication characteristics of a crank shaft pin turner bearing with dimples were studied. When increasing the dimples, the load carrying capacity due to the increased pressure was increased because those have sealing effects. Also, the run-out error of the bearing was decreased. Therefore, it is important to consider the depth, the number and the distribution of dimples when designing the hydrostatic journal bearing.

In this paper, it is proposed a method of optimizing path parameters for large-area laser processing. On-the-fly system is necessary for large-area laser processing of uniform quality. It is developed a MOTF(Marking On-The-Fly) board for synchronizing the stage and scanner. And it is introduced the change of the error due to the change of parameters and algorithm for large-area laser processing. This algorithm automatically generates stage path and a velocity profile using acceleration and deceleration parameters. Since this method doesn’t use a G-code, even if without expert knowledge, it has an advantage that can be accessed easily. Angle of one of the square of 350x350mm was changed from 50° to 80° and analyzed the error corresponding to the value of Ta. It is calculated the value of Ta of the best with a precision of 20um through measurement of accuracy according to the Ta of each angle near the edge.

This paper presents the judgment method of the rehabilitation extent using a spherical type digital finger force measuring system (SDFFMS). Stroke patients can’t use their fingers because of the paralysis of their fingers, but they can recover with rehabilitative training. The SDFFMS has been already developed by Kim (Author of this paper), and the finger grasping forces of normal people and stroke patients could be measured using it. But the SDFFMS could be not used to judge the extent of their rehabilitation, because the judgment method using it is not yet developed. In this paper, the characteristics tests for the grasping forces of normal persons and stroke patients were performed using the SDFFMS, and the judgment method of the rehabilitation extent was developed using the results. The tests confirm that the rehabilitation extent of stroke patients could be judged using the developed judgment method.

This paper reports a customized silver ink and its inkjet printing process on a cellulose electroactive paper (EAPap). To synthesize a silver ink, silver nanoparticle is synthesized from silver nitrate, polyvinylpyrrolidone and ethylene glycol, followed by adding a viscosifier, hydroxyethylcellulose solution, and a surfactant, diethylene glycol. The silver ink is used in an inkjet printer (Fujifilm Dimatix DMP-2800 series) to print silver electrodes on cellulose EAPap. After printing, the electrodes are heat treated at 200℃. The sintered electrodes show that the thickness of the electrodes linearly increases as the number of printing layers increases. The electrical resistivity of the printed electrodes is 23.5 μΩ-cm. This customized ink can be used in inkjet printer to print complex electrode patterns on cellulose EAPap to fabricate flexible smart actuators, flexible electronics and sensors.

In this study, drop-on-demand system using piezo-elecrtric inkjet printers was employed for preparation of collagen microspheres, and its application was made to the HepG2 cell-laden microsphere preparation. The collagen microspheres were injected into beaker filled with mineral oil and incubated in a water bath at 37℃ for 45 minutes to induce gelation of the collagen microsphere. The size of collagen microsphere was 100μm in diameter and 80μm in height showing spherical shape. HepG2 cells were encapsulated in the collagen microsphere. The cellladen microspheres were inspected by the microscopic images. The encapsulation of cells may be beneficial for applications ranging from tissue engineering to cell-based diagnostic assays.

The aim of this study was to assess the effects of artificial unloading induced by hindlimb suspension on the trabecular bone in tibiae. Twenty four 12-week-old Sprague-Dawley rats were assigned to 3 groups, namely, the control group (CON, n = 8), the hindlimb-suspended group (HLS, n = 8) and HLS with partial vibration group (HLSPV, n = 8). After 4 weeks, compared with CON group, HLS group had significantly greater decreases on BMD, BV/TV, Tb.N, Conn.Dn and increase on Tb.Sp (p < 0.05). However, there were no significant differences in BMD and the other micro structural parameters of tibial trabecular bones between CON and HLSPV (p > 0.05). These results implied that partial vibration might inhibit the bone loss induced by hindlimb suspension. Furthermore, we could expect to apply partial vibration system in space environment, to prevent bone loss in astronauts.