Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
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Design of a Multi-Step Warm Heading Process for Subminiature Screws

초소형 스크류 온간 다단 헤딩공정 연구

  • Jang, Yeon Hui (Department of Automotive Engineering, Seoul National University of Science and Technology) ;
  • Jeong, Jin Hwan (Department of Automotive Engineering, Seoul National University of Science and Technology) ;
  • Jang, Myung Guen (Department of Automotive Engineering, Seoul National University of Science and Technology) ;
  • Hong, Jae-Keun (Special Alloys Research Group, Korea Institute of Machinery and Materials) ;
  • Kim, Jong-Bong (Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology)
  • 장연희 (서울과학기술대학교 자동차공학과) ;
  • 정진환 (서울과학기술대학교 자동차공학과) ;
  • 장명근 (서울과학기술대학교 자동차공학과) ;
  • 홍재근 (한국기계연구원 부설재료연구소 특수합금연구그룹) ;
  • 김종봉 (서울과학기술대학교 기계자동차공학과)
  • Received : 2016.11.24
  • Accepted : 2017.01.16
  • Published : 2017.02.01
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Abstract

A multi-step warm forging process for subminiature screws is investigated. Due to the low formability of Titanium alloys, bit forming of Titanium screws is difficult by cold forging. In order to overcome this low formability of Titanium alloys, two candidate processes, i.e., multi-step forging and warm forging are introduced. First, a multi-step (two-step) forging process is investigated. The punch shape and stroke of forging during the first step is designed via various analyses. Finally, the bit formability is investigated at different forging temperatures. Analyses are carried out for two-step forging at various temperatures and the formability under these thermal conditions is compared.

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References

  1. Ra, S. W., Kim, I. R., and Hwang, S. T., “Study of Production and Material Properties of Micro Screw Using SWCH18A and SUS XM7 Materials,” Transactions of the Korean Society of Mechanical Engineers A, Vol. 38, No. 9, pp. 1043-1048, 2014. https://doi.org/10.3795/KSME-A.2014.38.9.1043
  2. Min, K. B., Kim J. B., Park, K., and Ra, S. W., “Evaluation of Clamping Characteristics for Subminiature Screws According to Thread Angle Variation,” J. Korean Soc. Precis. Eng., Vol. 31, No. 9, pp. 839-846, 2014. https://doi.org/10.7736/KSPE.2014.31.9.839
  3. Choi, B. H., Kim, H. J., and Kim, J. H., “Study on Fastened Properties by Applied to CFRP Laminates of Subminiature Screw,” Transactions of the Korean Society of Mechanical Engineers A, Vol. 38, No. 11, pp. 1239-1243, 2014. https://doi.org/10.3795/KSME-A.2014.38.11.1239
  4. Jeong, J. H., Lee, H. K., Kim, J. B., and Park, K., “Thread Shape Design Using Joining and Release Analysis of Bolts,” J. Korean Soc. Precis. Eng., Vol. 32, No. 6, pp. 523-528, 2015. https://doi.org/10.7736/KSPE.2015.32.6.523
  5. Lee, H. K, Park, K., Ra, S. W., and Kim, J. B., “Prediction of Joining Torque for Bit Depth of Subminiature Bolt,” Transactions of the Korean Society of Mechanical Engineers A, Vol. 38, No. 8, pp. 917-923, 2014. https://doi.org/10.3795/KSME-A.2014.38.8.917
  6. Bhattacharya, A., Sen, A., and Das, S., “An Investigation on the Anti-Loosening Characteristics of Threaded Fasteners under Vibration Conditions,” Mechanism and Machine Theory, Vol. 45, No. 8, pp. 1215-1225, 2010. https://doi.org/10.1016/j.mechmachtheory.2008.08.004
  7. Pai, N. and Hess, D., “Three-Dimensional Finite Element Analysis of Threaded Fastener Loosening due to Dynamic Shear Load,” Engineering Failure Analysis, Vol. 9, No. 4, pp. 383-402, 2002. https://doi.org/10.1016/S1350-6307(01)00024-3
  8. Kim, J. B., Seo, W. S., and Park, K., “Damage Prediction in the Multistep Forging Process of Subminiature Screws,” Int. J. Precis. Eng. Manuf., Vol. 13, No. 9, pp. 1619-1624, 2012. https://doi.org/10.1007/s12541-012-0212-2
  9. Choi, D. S., “Design of Cold Forging Process of Micro Screw for Mobile Devices,” Journal of the Korea Academia-Industrial Cooperation Society, Vol. 16, No. 6, pp. 3692-3697, 2015. https://doi.org/10.5762/KAIS.2015.16.6.3692
  10. Lee, J. E., Kim, J. B., and Park, K., “Finite Element Analysis for Improvement of Folding Defects in the Forging Process of Subminiature Screws,” J. Korean Soc. Precis. Eng., Vol. 32, No. 6, pp. 509-515, 2015. https://doi.org/10.7736/KSPE.2015.32.6.509
  11. Cockcroft, M. G. and Latham, D. H., “Ductility and the Workability of Metals,” Journal of the Institute of Metals, Vol. 96, No. 1, pp. 33-39, 1968.