The M-C oxygen delignification system for the eucalyptus line of our mill has started operation in January 1986.
The Kappa number and viscosity reduction are around 49 % and 19% respectively.
Also, the good results are shown in terms of brightness and dirt content.
Whereas, the reduction of total effective chlorine consumption and COD in the bleaching process are approximately 30 % and 50 %, respectively.

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In general, springs are flexible machine elements used for controlled application of force (or torque) or for storing and release of mechanical energy. A coiled wave spring (CWS), also known as a scrowave spring is a compression spring made of coiled wire or thin plate with waves giving a spring effect and offers the unique advantage of space savings when used to replace conventional coil springs. By reducing spring operating height, the coiled wave springs also offers a decreased spring cavity. A production cost savings is realized with a smaller assembly size and less material used in the manufacturing process. CWS makes it possible to accommodate higher thrust load within the limited axial space depending on the size of the wire (or plate), the number of waves, the height of waves, and the number of turns. In recent years, CWS with very high performance are widely applied to “Slip Clutch” and “Multi-Tooth Cutter”, “Retaining Ring”, “Face Seal”, and so on. However, nonlinear characteristics observed in large deformation of CWS has not been made clear yet. The large deformation analysis has been eagerly looking forward to as calculation formula. As it is, there exists no persuasive analysis. In this research, these nonlinear characteristics and spring constant for CWS are analyzed theoretically. A nonlinear large deformation theory is applied and exact analytical solutions are derived in terms of elliptic integrals, and then put into a nondimensional formula to facilitate the common understanding of large deformation phenomenon. Moreover, three concepts for the spring constant are newly proposed. In this study, some experiments were presented and the experimental results were compared with the theoretical formulas. As a results, the relation between the applied axial compression force and the nonlinear deflection obtained from the experiments is in good agreement with the relation predicted by the analytical theory.

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Using thinner sheet metal is effective in making the products with low cost and light weight. It also contributes to saving the energy and resources on earth. However, the rigidity and formability of sheet metal decrease when the thickness of sheet becomes thinner. Emboss process and restoration process can locally change the shape of a sheet metal, and also add partial work hardening. Therefore, there are some possibilities that the formability of thinner sheet metal is improved by these processing, like as the rigidity. In this study, emboss processes and restoration processes were conducted to the aluminum alloy sheet. The variations of the strength and formability of the aluminum sheet by these processing were investigated. The results showed that the yield stress of the sheet changed and the total elongation increased by performing these processing. On the basis of these results, the improvement of the formability of sheet metal was attempted by emboss process, restoration process and combination of these. The Erichsen cupping test and the deep-drawing test were conducted to the sheets having some processing patterns. From the result, it was confirmed that it was possible to improve the formability of sheet metal by adopting emboss process and restoration process properly.

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Coiled wave springs (CWS) are considered as multiple layered waved washers. They are light but powerful in limited spaces. In recent years, CWS have been applied to clutches of automobiles and expected to be applied to other uses. The formulas on the spring rates and stresses of CWS have been presented by an American spring maker of Smalley Steel Ring Company, Nishio, and Japan Spring Manufacturers Association (for short, JSMA). But none of them are practical, because the accuracy is not enough. Moreover the derivations of the formulas are not clear in the case of Smalley and JSMA. It has been observed that CWS show nonlinear spring characteristics in large deflection, however, the cause has not been made clear. In this research, spring rates and stresses for CWS are analyzed theoretically. A cause of the nonlinear spring characteristics is made clear, too. Then empirical formulas on the spring rates and stresses are derived by comparing the theoretical results with experiments and FEM analysis.

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