In this study, we examined the noise and the vibration in blanking with a press machine. Under the blanking speed V=15mm/s, we compared the blanking using a screw drive servo press with that using a general-purpose crank press. The blanking noise of the screw drive servo press was 10dB greater than that of the general-purpose crank press. Also, the vibration amplitude in blanking with the screw drive servo press was 0.3mm greater than that in blanking with the general-purpose crank press. This is the increase phenomenon of vibration in blanking. As a result of this study, we found that there are three factors that constitute the blanking vibration when using the screw drive servo press. The increase in vibration in blanking occurs by two factors; one is the planned descent of the press slide and the other is descent by motor thrust for position deviation dissolution.
It is difficult to predict springback, particularly in torsion, with high accuracy by finite-element (FE) simulation. Generally, more accurate springback prediction has been achieved mainly as a result of improved material models such as the Bauschinger effect and plastic anisotropy models. In this study, FE analysis of press forming taking account of tool deformations was carried out in addition to considering an accurate material model in order to improve springback prediction. Die deformations were measured to verify the accuracy of FE analysis. Press forming of curved hat-shaped products was carried out and the effect of the die stroke on torsion springback was examined. The effect of the elastically modeled parts of a press machine on springback prediction was investigated to improve the prediction of the relationship between the die stroke and torsion springback. It was demonstrated that the larger the number of elastically modeled parts, the better the correlation between the experimental results and the numerically simulated results. The differences in the torsion springback predictions between FE simulations with three different combinations of elastic and rigid parts were small although elastically modeled simulations have much better agreement with experimental results than the simulations with the fully rigid tool model.
Ni-plated steel wires used for springs in electrical appliances and other devices have good corrosion resistance. They are expected as alternatives to stainless-steel wire in a mildly corrosive environment. Further corrosion resistance is required for applications in automobile parts. The reasons for the low corrosion resistance are assumed to be a decrease in the average Ni-plated thickness upon drawing, and the variation in the Ni-plating thickness owing to the irregular deformation of the interface between the Ni-plating and the base material. In this study, the effects of the drawing conditions and Ni-plated thickness on corrosion resistance were examined. Under drawing conditions, the reduction in area varies from 0% to 40%. On the other hand, Ni-plated thickness is in the range from 2μm to 30μm. It is found that the drawing with a 10% reduction in area after applying Ni-plating thicker than 30μm are the most effective conditions for corrosion resistance.