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김도섭(Do-seop KIM),조순옥(Soon-ok JO),박대규(Dae-kyu PARK),전두환(Du-hwan CHUN),권오원(Oh-won KWON) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
In order to improve the productivity and quality of shuttle embroidery machine, gatter shaft to fixes and transfer cloth must be transferred with high speed and keep accurate transfer distance. However, if the gatter shaft is transferred with high speed, gatter shaft is easy to deform and a heavy load occur in shuttle embroidery machine because it has about 15m width and 1ton weight. Therefore, in this study, optimized shape of gatter shaft was drew using finite element method(FEM) and Statistical Design Support System(SDSS) for weight and bending stiffness.
김도섭(Do-seop KIM),Qiang YU,조순옥(Soon-ok JO),노석홍(Seok-hong NOH),전두환(Du-hwan CHUN) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
There have been serious debates about whether Pb should be removed from solder joints, in view of environmental problems. Therefore, many studies have been aggressively undertaken to develop technologies for replacing Sn-Pb solder with lead-free alternative. From the results obtained so far, it has been proven that the fatigue strength in lead-free solder joints is almost equivalent to the fatigue strength of Sn-Pb eutectic solder joints. However, a new problem is that voids are very easily formed in lead-free solder joints during the reflow process, and the effect of the voids on the fatigue strength of solder joints has attracted attention. In this study, the relationship between the voids and fatigue strength of solder joints was examined using mechanical shear fatigue test and FEM (finite element method) analysis. Using the mechanical shear fatigue test, the effect of the position and size of voids on fatigue crack initiation and crack propagation has been investigated. And quantitive evaluation of fatigue life of solder joints with the voids has been enabled by Manson-Coffin's law and Miner' rule.