Optimization of winding conditions for preventing roll defects caused by thermal-viscoelastic property and experimental verification

Plastic films are used in many high functional products. They are produced on roll to roll system. The films are continuously wound in the shape of roll using this system. The wound roll is shipped to the store and transportation, in some cases, heat-treated under the various temperatures. Then internal stress of wound roll will be changed due to thermal strain and viscoelastic properties over time. Those factors causes to wound roll defects such as slippage or wrinkling. This paper describes optimization method of winding tension for preventing the wound roll defects by thermo-viscoelastic property based on the optimum design technique. As a result, the optimized tension is confirmed experimentally that the internal stress distributions are very much improved for preventing both wrinkling and slippage

Optimization of wind-up tension of webs preventing wrinkles and slippage with experimental verification

This paper describes the optimization method of wind-up tension to prevent wound roll defects, mainly star defect (wrinkling) and telescope (slippage), based on the optimum design technique. Hakiel's nonlinear model with air entrainment effects is applied to analyze in-roll stress distributions in the radial and tangential directions. It is well known experimentally that a decrease in the wind-up tension prevents star defects due to negative tangential stress under winding. Thus, in the present optimization method, wind-up tension is gradually decreased in the radial direction to minimize the tangential stresses under the constraint of nonnegative tangential stresses. At the same time, we consider the friction conditions to prevent the slippage between web layers due to a decrease of radial stresses and friction force. Successive quadratic programming, which is the typical mathematical programming method, is used as the optimization technique. Wind-up tension is expressed by the third-order spline curve of a radial coordinate. The linear function with respect to the radial coordinate is used as the original wind-up tension. The optimized wind-up tensions are obtained for various winding condition, and we confirmed theoretically and experimentally that the in-roll stress distributions were very much improved for preventing wrinkle and slippage by optimization method proposed

Improvement of slippage and wrinkling of transporting webs using micro-grooved rollers

We describe an entirely new method of improving the slippage between web and roller. First, the concept of a micro-grooved roller is introduced, and then a theoretical model for estimating the slip onset velocity under the transport of web by the micro-grooved roller is formulated. The predicted results are compared with the experimental data to verify the applicability of the prediction model of slippage. Moreover, the web-wrinkling condition, which is in a trade-off relationship with the slippage condition, is also considered in the model. From the theoretical and experimental results, it is confirmed that the optimized micro-grooved roller is very effective in improving the slippage and wrinkling of thin web under the high-speed transport with low tension at the actual production line

Friction characteristics between thin plastic film and steel roller

To establish the Roll-to-Roll Printed Electronics, which can be applied to manufacture the high functional thin film based devices, it is needed to combine the Roll-to- Roll transportation system and coating technology effectively. For that purpose one of important factors to be considered is the friction characteristics between the thin plastic film and steel roller. In past research, however, as far as authors know, there is no research which describes friction characteristics between thin plastic film and steel roller. In this paper, the static friction between the plastic film and steel roller was measured by pulley method while changing film thickness of film, roller surface roughness, web tension, and relative humidity. As a result, the static friction coefficient between thin film and steel roller was significantly influenced by film thickness and roller surface roughness, web tension and relative humidity have an effect on the static friction coefficient. From analysis of variance, it was confirmed statistically that contribution ratio of three factors, relative humidity, web tension and surface roughness which were 23.8 %, 32.6 % and 36.1 %, were very high

The Multiphase Flow CFD Analysis in Journal Bearings Considering Surface Tension and Oil-Filler Port Flow

This chapter presents the multiphase computational fluid dynamics (CFD) analysis on oil-lubricated high-speed journal bearings considering the oil-filler port. Journal bearings are widely used for high-speed rotating machinery such as turbines, compressors, pumps, automobiles, and so on. They can support the rotating shaft utilizing the oil lubrication film wedge effects used in the bearing clearance. Previously, in the analysis of journal bearings, which clearance is very narrow compared with shaft diameter, the Reynolds equation has been used on journal bearing analysis because of its applicability on the narrow space calculation and its low calculation cost. However, the gaseous-phase area generated in the journal bearing and the effect of oil-filler port cannot be reproduced accurately using the method. Under these backgrounds, some researchers use the CFD analysis to calculate the journal bearing characteristics in recent years. In this chapter, the authors describe the multiphase flow CFD analysis on journal bearing based on our previous studies . At first, the multiphase CFD calculation model on journal bearing and the experimental method are explained. Then, four types of calculation results under flooded and starved lubrication conditions are compared to the experimental ones. Additionally, the effect of surface tension on journal bearing characteristics is discussed. Finally, the CFD thermal analysis results under two types of supply oil conditions are shown

Optimum Design of Thrust Oil Bearing for Hard Disk Drive

This paper presents the application of optimization method developed by Hashimoto to design oil lubricated thrust bearing for 2.5 inch form factor hard disk drive (HDD). The designing involves optimization of groove geometry and dimensions. Calculation is carried out to maximize the dynamic stiffness of the thrust bearing spindle motor. Static and dynamic characteristics of the modeled thrust bearing are calculated using the divergence formulation method. Results show that by using the proposed optimization method, dynamic stiffnesses values can be well improved with the bearing geometries not being fixed to conventional grooves

Evaluation of physical properties of thin film and measurement of unsteady thermal stress

Winding defect such as the roll wrinkles or slips to lose the value of the product. Winding defect is caused by the internal stress condition in the roll and the temperature change of the roll after winding. Therefore, it is essential to analyze the internal stress theoretically. However, the tendency of internal stress to occur as the film thickness becomes thin is not known. The internal stress of the roll was measured at each temperature. Further changes in internal stress were also measured by changing the ambient temperature around the roll.The winding device used in this research is a structure reproducing the unwinding and the rewinding in the roll-to-roll production system. A film-like pressure sensor was used to measure the radial internal stress of the roll. After winding up the film, the internal stress in the radial direction inside the roll was measured when the temperature around the roll was heated for 12 hours. Measurement frequency was measured for internal stress every hour.In the PET film with a film thickness of 40 μm, the internal stress in the radial direction inside the roll was measured when the roll surrounding temperature was heated for 12 hours. For the middle and outer layers, the internal stress gradually increased with the lapse of time. It is considered that this increased the pressure by thermal expansion from the outer peripheral side of the roll. However, the value of the stress in the inner layer decreased greatly. This is thought to be caused by uneven heating due to the heat source, winding wrinkles occurred in the vicinity of the sensor sandwiched between the rolls, and stress relaxation occurred

Influence of exposure to new circumstances on pharmacokinetics of plasma drugs concentrations in rats.

The influences of emotional changes induced by being exposed to a new environment on the pharmacokinetics of plasma drug concentration were studied in male Wistar rats. Transfer from a familiar home cage to a new home cage was considered to induce psychological (non-physical) emotional changes. First, nicorandil and zonisamide, drugs that act on the peripheral system and central nervous systems, were used, respectively. Immediately after oral administration of nicorandil (10 mg/kg) or zonisamide (50 mg/kg), the animals were transferred to new home cages. Plasma nicorandil and zonisamide concentrations were determined by high-performance liquid chromatography at 1 and 4 h after administration. Plasma nicorandil concentration in the group transferred to new home cages was significantly decreased relative to levels in the non-transferred control group. However, zonisamide concentrations were unchanged. These findings suggest that the pharmacokinetics of nicorandil, but not those of zonisamide, tend to be influenced by non-physically induced emotional changes.</p

Development of intelligent plastic film winder "Windstar"

Flexible continuous plastic films are used to produce various products, including optical films and packaging materials, because plastic film is suited to use in mass production manufacturing processes. Generally, the web handling process is applied to convey the plastic film, which is ultimately rewound into a roll using a rewinder. In this case, wrinkles, slippage and other defects may occur if the rewinding conditions are inadequate. In this paper, the authors explain the development of a rewinder system that prevents wound roll defects - primarily starring and telescoping. The system is able to prevent such defects by optimizing the rewinding conditions of tension and nip-load. Based on the optimum design technique, the tension and nip-load are calculated using a 32-bit personal computer. Our experiments have also empirically shown that this rewinder system can prevent roll defects when applying optimized tension and nip-load. Additionally, inexperienced operators can control this system easily

KEY FACTORS FOR THE SEPARATION OF SILICON AND IRON DURING PHOSPHORUS RECOVERY FROM SLAG DISCHARGED FROM THE DOUBLE-SLAG REFINING PROCESS

In the present study, we developed a technology for concentrating and recovering phosphorus from slag-like phosphorus-containing unused resources and applied it to slag discharged during the latest steelmaking process, that is, double-slag refining process (DRP). The technology we developed consists of the following four processes: Process (1) is the initial acid elution; Process (2) involves alkali precipitation; Process (3) is the second acid elution; and, Process (4) utilizes ion-exchange. In Process (1), the addition of DPR slag to 0.5 M of a nitric acid solution for 24 min resulted in sufficient phosphorus dissolution. In Process (2), ammonia was added to the dissolved solution, and phosphorus was precipitated with high efficiency. The timing of the addition of ammonia significantly influenced the removal of silicon and iron, which would have been inconvenient to accomplish in subsequent processes. In Process (3), the precipitation obtained in Process (2) was re-dissolved in a nitric acid solution. The dissolution of phosphorus together with other elements progressed sufficiently, and we confirmed that silicon could be completely separated as silica by using high-concentration nitric acid at this stage. The fact that silicon could be removed during Process (3) was an important finding, since silicon could not have been separated in the Process (4). In Process (4), by passing the phosphorus-containing solution obtained in Process (3) through an ion exchange resin, elements other than phosphorus and silicon could be removed, which confirms that the range of applications for this technology could be expanded