This paper has been carried out the forming analysis, die stress analysis, and relevant tests for the straightness improvement of hollow shafts with blocktooth. Hollow forward extrusion is a process that a material in a die is pressed with a punch and the material is formed into the same direction through the gap of a mandrel and a bottom die. For an asymmetric shaped product, due to the difference of reduction ratios of the cross sections in its extruding, a phenomenon that the product bends from the difference of the flow speed comes to occur. As applying the key to the mandrel has a uniform flow speed, bending problem was solved. These were processed using Deform-3D as a finite-element analysis program. Analysis was compared with the experiment. Keyway height of the mandrel has been confirmed that the straightness best when it comes 0.1mm. These study are expected to be available as fundamental data in die design necessary for the manufacture of asymmetric goods in the future.

1. 서 론
 2. 비대칭 단면을 갖는 중공형 제품
 3. 제품 모델링
 4. 유한요소해석
  4.1 성형해석
 5. 금형응력 해석
 6. 실 험
 7. 결 론
 후 기
 References

• 이헌주(국립 공주대학교 일반대학원 기계공학과) | H. J. Lee
• 박용복(국립 공주대학교 기계자동차공학부) | Y. B. Park
• 전용두(국립 공주대학교 기계자동차공학부) | Y. D. Jun
• 신경식(국립 공주대학교 일반대학원 기계공학과) | K. S. Shin
• 전성식(국립 공주대학교 기계자동차공학부) | S. S. Cheon 교신저자