The present study is the development of recyclable micro pale expansion drilling bit. The domestic market will gradually be suppressed by the new developed ring one in the use of ring bit(non-recyclable) in this business. Existing casing drilling and insertion method is applied by order of the casing inserted after drilling, which has the disadvantage that a long construction time, device costs and labor consuming. When the steel pipe multi-bit-only expansion drilling is developed, enterprise sales and employment effects can occur. If the performance of the developed products through the product equal to or superior to the domestic component parts are developed proprietary technology acquisition and cost savings, as well as the construction period of about 30%, and the expected reduction of 70% in material costs are expected.

Abstract
 1. 서론
 2. 마이크로파일용 확공 비트 개발의 목표 및 내용
  2.1 기술개발목표
  2.2 기술개발내용
 3. 향후 연구 방향
 References

• 이정익(Dept. of Mechanical Design, INHA Technical College) | Jeong-Ick Lee
• 고병갑(Dept. of Mechanical Engineering, INHA Technical College) | Byung-Kab Ko Corresponding Author