• Title/Summary/Keyword: Melting efficiency

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Scheduling of a Casting Sequence Under Just-In-Time (JIT) Production (적시 생산 방식에서의 주조공정 스케줄링)

  • Park, Yong-Kuk;Yang, Jung-Min
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.32 no.3
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    • pp.40-48
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    • 2009
  • In this article, scheduling of a casting sequence is studied in a casting foundry which must deliver products according to the Just-in-time(JIT) production policy of a customer. When a foundry manufactures a variety of casts with an identical alloy simultaneously, it frequently faces the task of production scheduling. An optimal casting schedule should be emphasized in order to maximize the production rate and raw material efficiency under the constraints of limited resources; melting furnaces and operation time for a casting machine. To solve this practical problem-fulfilling the objectives of casting the assigned mixed orders for the highest raw material efficiency in a way specified by the customer's JIT schedule, we implement simple integer programming. A simulation to solve a real production problem in a typical casting plant proves that the proposed method provides a feasible solution with a high accuracy for a complex, multi-variable and multi-constraint optimization problem. Employing this simple methodology, a casting foundry having an automated casting machine can produce a mixed order of casts with a maximum furnace utilization within the due date, and provide them according to their customer's JIT inventory policy.

The Effects of Welding Parameters on Quality in Lap Joint Fillet Welds of Thin Plate by Plasma Welding (Plasma 용접에 의한 박판 겹치기 이음 필릿 용접부의 품질에 미치는 용접 변수의 영향)

  • Park, Kun-Gi;Yang, Jong-Soo;Cho, Sang-Myung;Yoon, Hun-Sung
    • Special Issue of the Society of Naval Architects of Korea
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    • 2006.09a
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    • pp.122-127
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    • 2006
  • In case of lap joint fillet welds of thin plate, the example which is applicable to Plasma Welding increases substituting for the exiting TIG Welding but the quality of Plasma arc welding has a special feature influenced sensitively by the condition of welding caused by controlling the various parts of welding torch. This research is purposed to improve lap joint fillet welds of thin plate in high quality and attain the high productivity and it is examined that how the change of electrode tip angle and Setback has an effect on the quality of welding and it is investigated how the change of Setback and Standoff has an effect on Melting efficiency using Response Surface Analysis.

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The Eeffect of Arc Length and Shield Gas on Penetration Aspect Ratio in A-TIG Welding (A-TIG 용접에서 용입 형상비에 미치는 아크길이와 실드가스의 영향)

  • Park, In-Ki;Ham, Hyo-Sik;Cho, Sang-Myung
    • Journal of Welding and Joining
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    • v.26 no.6
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    • pp.42-47
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    • 2008
  • TIG welding enables to produce high quality weldment. However it has some problems such as shallow penetration and large distortion due to low penetration aspect ratio after welding. In order to overcome those problems, there are many ongoing studies on A-TIG welding, which use active flux. In this study, the effect of arc length and shield gas on penetration aspect ratio with melt-run welding on STS 304 6t, on which active flux was spreaded, was investigated. Arc length was changed from 1mm to 3mm, and aspect ratio became higher as arc length was decreased in this range. 100% Ar gas, Ar-$H_2$ mixed gas, Ar-He mixed gas, and 100% He gas were used as shield gas in this study. When Ar-$H_2$ mixed gas, Ar-He mixed gas, and 100% He gas were applied, penetration and melting efficiency were both increased as compared with 100% Ar gas. Aspect ratio was the highest with Ar-2.5% $H_2$ mixed gas.