Tapping Small Diameter Screw Threads with Ultrasonic Vibration

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06133
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Design engineering/Machine functional elements/Tribology
• Research Institution: Nagano National College of Technology
• Principal Investigator: Okada Manabu 長野工業高等専門学校, 機械工学科, 教授 (70249788)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 機械要素 / ねじ / 超音波振動 / 切削加工 / 塑性過去

Outline of Final Research Achievements

The cutting and plastic working of the small diameter female screw and the tightening of the tapping screw were performed while applying ultrasonic vibration. The cutting and plastic working thread diameter is M1 and the tapping screw is M2, which are the smallest diameters on the market. There are four types of ultrasonic vibration frequencies: no vibration, 28kHz, 40kHz, and 60kHz. The cutting torque or screwing torque could be reduced most when the vibration frequency was 40 kHz in any of cutting, plastic working and tapping screw tightening. It is considered that the acceleration of ultrasonic vibration increases in proportion to the square of the vibration frequency, but the higher the vibration frequency, the smaller the size of the ultrasonic vibrator and the less power that can be input.

Free Research Field

機械要素

Academic Significance and Societal Importance of the Research Achievements

現在、めねじ加工用のタップの呼び径の下限がM1であるのは、小径のタップはねじり負荷に弱く、加工中に折れやすいからである。本研究の成果によって加工トルクを低減できれば、さらに小径のめねじ加工が可能になる。それによって、小型化の要求が強い携帯情報端末やIoT機器の組み立てに使うねじを小径化できるほか、限られたスペースに複雑な機構を組み込む高級腕時計などの高付加価値製品の開発や、各種計測用センサー、ドローン、医療機器などの精密機器の小型化に貢献できると考えている。