Non-contact measurement of welding surface temperature in laser welding of metal and resin parts

Research Project

Project/Area Number	16K06010
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Production engineering/Processing studies
Research Institution	Nagoya Institute of Technology
Principal Investigator	Hayakawa Shinya 名古屋工業大学, 工学(系)研究科(研究院), 准教授 (10314080)
Project Period (FY)	2016-04-01 – 2019-03-31
Project Status	Completed (Fiscal Year 2018)
Budget Amount *help	¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000) Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2017: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000) Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Keywords	レーザ接合 / 接合面温度 / 放射温度計 / 放射率 / インプロセス測定 / 非接触測定 / 接合界面温度 / 電場増強 / 反射光 / 分光スペクトル / 機械工作・生産工学 / 光物性 / レーザ加工
Outline of Final Research Achievements	This study investigated a signal superimposing on the output signal of radiation thermometer in order to realize the non-contact measurement of welding surface temperature in laser welding of metal and resin parts. Since the superimposing signal disturbs the temperature measurement, the cause of the signal was first clarified using a monochromator. It was found that the cause of the superimposing signal measured during the laser welding is laser light reflected from the welding surface. This result suggests that the superimposing signal can be eliminated using an appropriate optical filter. Then we invented that emissivity of the welding surface, which varies with progress of the welding process, could be measured during the welding process using the superimposing signal. From these results, non-contact measurement of welding surface temperature in laser welding of metal and resin parts was moved toward the realization.
Academic Significance and Societal Importance of the Research Achievements	放射温度計による温度測定を妨げると考えられた重畳信号が，温度測定に不可欠な放射率の測定にむしろ有用であることを示したことは学術的な価値が高い．放射率を加工中に測定できることは，サンプルによる事前の検定作業を不要にするほか，接合加工の進行に伴って放射率が変化することにも対応できるようになるため測定精度の向上につながる．これにより接合加工中の接合面温度の測定と管理が可能になることで接合品質と生産性の向上が期待される．