Shigeru Nagasawa

Effect of crease depth and crease deviation on folding deformation characteristics of coated paperboard

Abstract Paperboard die cutting, which includes creasing, is a production technique widely spread in many fields such as foods, stationery packaging. For the improvement of productivity or the improvement of quality on die cutting, the estimation of endurance on die tools and the estimation of material properties on paperboard are required. Creasing is one of most important mechanical behavior for paperboard die cutting. This paper reports on a fundamental deformation behavior and fracture modes as delamination patterns of coated paperboard creased. The creasing characteristics were investigated by varying the crease depth and the lateral deviation of rule clearance. By reviewing the bending moment resistance and by observing the delamination process of creased part under a folding test, the variance of bending moment characteristics of creased part was discussed. Furthermore, by adding the lateral deviation of rule clearance, the correlation between the moving direction of the folding point and the non-symmetrically delaminated zones was also investigated.

Support system for finite element analysis

Abstract This paper describes work aimed at developing an intelligent support system for finite element modeling and a methodology for managing input data model. Analyzing various statement structures of input data, three structural interface models — the hierarchical browser, the spread sheet and the model generator — are proposed for advanced representation and editing. Two knowledge models composed of macro visual data representation (user oriented model) and micro regularized data representation (processor oriented model) are revealed in conformity with the approach of object-orientation. Moreover, an extended relational schema composed of a composite object (assembly of functional elements) and several abstracted scalar indexes has been implemented for case retrieval.

Effects of Scoring Depth, Tracking Angle, Rubbering on Bending-Moment Relaxation of Creased Paperboard

This work deals with the time-dependent creasing characteristics of coated paperboard. The correlation between the bending strength (resistance) and time-dependent problems on the actual processing phenomenon has not been sufficiently discussed in the past. It is difficult to estimate various time-dependent responses from the initial strength of the creased part, such as the maximum bending moment and the initial gradient of bending moment. In this study, therefore, a prototype testing apparatus has been applied to investigate about the dynamic relaxation of bending moment. In order to reveal the relaxation characteristics of the bending resistance during the folding motion from an initial position up to various tracking angles, a white-coated paperboard of 0.3 mm thickness was scored with a creasing rule and a grooved counter face plate under a specified feed velocity, and then the bending test was carried out by varying the tracking angle. Through this work, the followings were obtained: (1) The relaxation of the bending moment was characterized by an exponential coefficient which was independent to the nominal shear strain and the tracking angle. (2) The relaxation depends on the rubbering condition.

ANALYSIS OF CUTTING CHARACTERISTIC OF POLYCARBONATE SHEET SUBJECTED TO WEDGE INDENTATION BY KNIFE EDGE AND GROOVED PLATE

Asymmetric plunge cutting by using a grooved knife edge plate was proposed for advanced die cutting of a polycarbonate (PC) sheet. By varying the tip angle αU and the tip thickness w U of knife edge in the counter plate, and combining a standard steel cutting rule of 42° center bevel blade, a cutting load response of PC sheet was experimentally investigated, and the deformation was also observed by a CCD camera. Furthermore, an FEM simulation was carried out by varying the lower tip thickness for revealing the effect of interference of lower grooved counter plate. Through this work, the following were found: 1) there were two deformation modes of sheared profile; 2) the lower tip thickness w U was a primary factor, compared to the lower tip angle of αU; 3) the equivalent wedge angle effect was revealed with respect to the upper/lower angles α and αU, while the PC sheet was bent up by the lower knife indentation.

Effects of Combined Ultrasonic Vibration during the Sinking EDM Process for Cemented Carbide

In recent years, to improve the electrical discharge machining properties, several trials have been applied with the ultrasonic vibration system which was combined on the sinking electrical discharge machine. In this paper, the effects of the ultrasonic vibration were investigated with the designed sinking EDM machine. Some experimental parameters of tool electrode polarity, rotational workpiece speed and directions were examined during the sinking EDM process on the cemented carbide material of G5. Material removal rate, electrode wear ratio and surface roughness were estimated as the machining properties under finishing machining conditions. The experiments were carried out on ultrasonic longitudinal frequency 59 kHz and electrode spindle till 1,000 rpm. Two rotational apparatuses were used simultaneously on the opposite rotational direction during discharge machining. The discharge conditions were estimated with the waveforms analysis. As the results, the EDM device system which was combined ultrasonic vibration, improved the material removal rate and surface roughness of the EDMed workpiece.

Deformation Characteristics on Surface Layer of White-Coated Paperboard by Center Bevel Blade Subjected to Pushing Load

This paper describes for breaking behaviors on the surface layer of a white-coated paperboard during indentation of a center bevel blade. Cutting load response of the paperboard was measured regarding the indentation depth of the blade and the deformation flow in a side view of the paperboard was observed by a CCD camera in order to investigate the effect of blade tip angle on the surface failures of the paperboard. The surface breaking strength of paperboard was analyzed by using Finite Element Method (FEM). Through the experiment and FEM simulation, the followings were revealed. 1) There is a certain critical value of tip angle C at which an inflection load response disappears and also the surface failures are restricted. 2) When the tip angle is less than the C, there is an inflection point as the surface-layer breaking and its surface breaking point was strongly related to the maximum principal stress on the surface. 3) After the surface breaking, the deformation flow and its cutting resistance are strongly affected by the de-laminated and the raised-up of the inner-layer.

Bonding Strength of W-Cu Joint by PECS Method

To make the tungsten and copper joint, several methods has been tried using the diffusion bonding system. When the thin plating Ni layer was used as the interlayer on tungsten surface, it bonded with copper under low bonding temperature and short holding duration by the pulse electric current sintering (PECS) machine. The effects of bonding temperature, bonding duration time, bonding pressure and the difference of specimen shape on the bonding strength were investigated. The tensile strength of joints depended on these factors. Highest strength attained to the copper tensile strength.

Estimation of Bending Characteristics of Creased White-Coated Paperboard Subjected to In-Plane Compressive Load Using V-Block Fixtures

This research work deals with the development of simple evaluation method of creasing characteristics of coated paperboard. The recent-developed testing device (CST, crease stress tester) is able to control the bending rotation speed of the creased part of a worksheet and its sleeping time at a specified angle position. Although the CST is a high grade equipment and useful for analyzing the bending characteristics, while the cost performance of equipment for simply having assurance of crease stiffness is another problem. The authors have developed a simple evaluation method for knowing the creasing characteristics on a folded line of paperboard, which is subjected to an in-plane compressive load by using a set of V-block fixtures. Through the bending experiment of creased paperboard, the proposed V-Block based estimation method has been compared with some analysis results based on the CST, and its effectiveness was revealed. The primary results were as follows: (1) The buckling strength as the maximum compressive load is characterized with respect to the nominal shear strain (normalized scoring depth of crease). (2) The transitional point as variation tendency of compressive load (by the V-Block) well coincides to the disappearance of peak bending moment of CST. (3) The equivalent bending moment of V-Block well coincides to the CST based bending moment resistance when choosing a certain large folding angle. (4) The proposed V-Block method can be effectively used for a certain large range of folding angle.

Effects of Blade Tip Geometry on Cutting Characteristics of Lead Alloy Sheet Subjected to Wedge Indentation

This research work was carried out aiming to investigate the cutting characteristics of a soft metallic sheet subjected to the wedge blade indentation. The indentation of a lead alloy worksheet was conducted, experimentally using a center bevel blade in order to reveal the experimental background of the indentation. In addition, to investigate the effects of the blade tip geometry, the bevel angle of the wedge blade, on the cutting characteristics of the worksheet, the finite element method (FEM) analysis was conducted. By varying the bevel angle, the critical levels of stresses for the necking of the worksheet were detected. Also, it was found that the bevel angle affected the cutting load resistance, the necking of the worksheet and the final feature of the wedged edge.

Analysis of Acoustic Emission on White-Coated Paperboard During a Wedge Cutting Process

In our social life, paperboard and its finished products have been become widespread as any recycled materials. The structure of paperboard is composed of multiple plies (normally, lamination structure of 3~8 layers) with the hydrogen-bonded natural fibers which have the vertically beaten shape. The material property of paperboard has an anisotropic characteristic and may be understood as orthotropic-nonlinear elasticity [1].