Liquid Impact Sheet Metal Deformation of Superni (Inconel) 718 using Inclined Edge (Conical) DIE
Abstract
Liquid/Hydraulic impact forming is a sheet metal forming process in which a dead weight drop freely from a certain height over a piston working inside a cylinder containing liquid or hydraulic fluid, generates shock waves which reach the sheet metal kept at a lower part of the cylinder and deforms it to the shape of the die placed below the sheet metal. In the present work Taguchi design of experiments (DoE) technique is used in order to find the effect of input parameters on impact force for deformation of superni (Inconel) 718 using inclined edge die. Contribution of each factor on output is determined by ANOVA (Analysis of Variance) and also an attempt is made towards green manufacturing by adopting used gear and vegetable oils as operating fluids. The outcome of this research will be very much useful for medium and small segment industries in getting the pre-form of the product with least cost.
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Introduction
1.1 Liquid impact forming:
Oil can be considered as a homogeneous fluid incapable of supporting any shear. An impulsive load causes a rearrangement of fluid by flow through any boundary displacements caused by loading. A change in the pressure results in change in volume and a spontaneous local pressure is transmitted to other stations in the fluid through “elastic wave of disturbance” commonly called as stress waves.
Conclusion
● Fig.4: Demonstrated that the variation of impact is 7% ie., 28.96 kN to 31.16 kN when the thickness varies from 0.2 mm to 0.5 mm when all the remaining input parameters at low level. When input parameters are at high level the variation of force is less than 7% for change in the thickness of 0.2 mm 0.5 mm. This indicates that loading may be reached the yield phenomenon of material at higher levels of impact parameters.
● Fig.5: Indicates the variation of impact force when the height of hammer changes from 190 cm to 250 cm when input parameters are at low level the variation of force is about 7% whereas for higher level of input parameters it is 7%. This observation n establishes that at higher level of input parameters the force transmitted to the work piece is reducing which may be attributed to dynamics of fluid.
● Fig.6: Shows the variation of impact force when the weight of hammer changed from 15 Kg to 25 Kg. The variation of force when input parameters are at low level is 24% whereas for higher level is 20% this concerned that higher level of parameters considering the yield point phenomenon of work piece material.
● Fig.7: Shows that variation of impact forces when the viscosity changes of fluid from 9.88 to 11.36 Poise. When impact parameters are at low level the impact force is reduced with increase in viscosity by 1.31 kN whereas higher level of input parameters is 1.32 kN. Which may be attributed to the power transmitting ability of fluid in conical die.