• Title/Summary/Keyword: Humping Bead

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Fast laser welding with scanner on the joint between AZ31 thin sheet and die-casted AZ91D frame for smart phone application (스캐너를 이용한 AZ31 극박판재와 AZ91D 다이캐스팅 프레임의 고속레이저용접)

  • Lee, Mok-Young;Seo, Min-Hong
    • Laser Solutions
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    • v.18 no.1
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    • pp.1-6
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    • 2015
  • High welding speed and narrow weld seam are favorable for welding of magnesium alloy. Magnesium alloy is recommended for the smart frame because it has several advantages such as low density, high thermal conductivity, EMI shielding capability and good cast ability. This study is for the assembly welding of the magnesium smart frame with high productivity, good performance and low cost. The window for battery on AZ91D frame produced by die-casting was prepared by CNC machining. Corresponding AZ31 blank of 0.2mm thickness was prepared by die-blanking cut. All system set was fixed at the stationary bed but the laser beam was manipulated by scanner up-to 1,000mm/s speed. The weld joint between AZ31 sheet and AZ91D frame was welded by fiber laser on 850~1,000W output power. The joint showed penetration enough but some humping bead. The distortion by the weld heat was almost free because of the quick dissipation of the heat by small beam size and fast welding. Consequently, the thinner magnesium foil was assembled successfully to the magnesium frame of mobile phone.

The Weldability of Primer-coated Steel for Shipbuilding by $CO_2$ Laser (조선용 Primer코팅강판의 $CO_2$레이저 용접성)

  • Park, Hyun-Joon;Kim, Jong-Do;Kim, Young-Sik
    • Proceedings of the KSME Conference
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    • pp.316-321
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    • 2003
  • The spatter and porosity could be occurred during $CO_2$ CW laser welding of Primer-coated Steel for Shipbuilding. This study has suggested an alternative idea by examining of weld-defect formation mechanism. The primer-coated plate has caused the spatter, humping bead and porosity and these are main part of the welding defect, attributed to the powerful vaporizing pressure of primer attached on the base metal. The zinc of primer has a boiling point that is the lower temperature than melting point of steel. Zinc va}X)f will build up at the interface between the two sheets and this tends to deteriorate the quality of the weld by ejecting weld material from lap position or leaving porosity. Therefore introducing a small gap clearance in the lap position, the zinc vapor could escape through it and sound weld beads can be acquired. In conclusion, we suggested the occurred and prevented mechanism of weld defects with searching the factor.

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