CAJ | 학술논문

以厚度1、0.5和0.2 mm的微制品为研究对象，采用等规聚丙烯（iPP）材料进行微注塑实验，通过改变注射速度研究剪切历史对制品内部形态结构和力学性能的影响，并对微制品内部形态结构和力学性能的影响关系进行分析，不同注射速度下的剪切历史采用Moldflow分析获得。结果表明：1 mm和0.5 mm微制品厚度方向均呈现皮芯结构，且皮芯交界处的过渡层出现不完善的串晶层，0.2 mm微制品呈现含有柱晶结构的皮芯分层结构。对于3种厚度的微制品，熔体整体剪切水平随着注射速度的提高而提高，1 mm和0.5 mm制品的皮层厚度随注射速度增大而减小，模量、断裂强度和断裂伸长率均随皮层厚度增大而增大，屈服应力变化不明显，0.2 mm制品的皮层厚度随着注射速度的增大而增大，且随着皮层厚度的增大，断裂强度、模量和屈服应力增大，断裂伸长率逐渐减小。
이후도1、0.5화0.2 mm적미제품위연구대상，채용등규취병희（iPP）재료진행미주소실험，통과개변주사속도연구전절역사대제품내부형태결구화역학성능적영향，병대미제품내부형태결구화역학성능적영향관계진행분석，불동주사속도하적전절역사채용Moldflow분석획득。결과표명：1 mm화0.5 mm미제품후도방향균정현피심결구，차피심교계처적과도층출현불완선적천정층，0.2 mm미제품정현함유주정결구적피심분층결구。대우3충후도적미제품，용체정체전절수평수착주사속도적제고이제고，1 mm화0.5 mm제품적피층후도수주사속도증대이감소，모량、단렬강도화단렬신장솔균수피층후도증대이증대，굴복응력변화불명현，0.2 mm제품적피층후도수착주사속도적증대이증대，차수착피층후도적증대，단렬강도、모량화굴복응력증대，단렬신장솔축점감소。
Micro injection molding experiments were conducted to investigate the influence of shear history on morphology, microstructure and mechanical properties of the micro-scale parts by changing injection speed based on the iPP parts with thickness of 0.2, 0.5 and 1 mm. Shear rate was analyzed with software Moldflow. Skin-core structure appeared in the thickness direction in both 0.5 mm and 1 mm parts, and imperfect shish-kebab structure appeared in the transition layer between skin layer and core layer of 0.5 mm and 1 mm parts, however, column crystal was shown in the transition layer of 0.2 mm parts. The whole shear level in shear history increased with increasing injection speed for all the parts with three thicknesses. The ratio of skin layer of 0.5 mm and 1 mm parts decreased with increasing injection speed, and yield stress, elongation at break, breaking strength and modulus decreased as the ratio of skin layer decreased. For 0.2 mm parts, the ratio of skin layer increased with increasing injection speed, and yield stress, breaking strength, modulus increased with increasing ratio of skin layer, while elongation at break decreased.