摘要
金屬毛細管目前大多是採用抽拉製程的方式來進行成形加工，當尺寸縮小到趨近於微米級時，通過模孔的材料僅存數十個晶粒在於管壁周圍，此時進行抽拉過程中，因尺寸效應的關係導致表面摩擦力顯著增加，相對的拉應力也會提高，容易產生頸縮破裂。因此可透過微旋鍛縮徑成形來取代抽拉製程上無法克服的成形範圍，藉由微旋鍛之成形特性，多向微小增量鍛打，透過轉換製程的同時將拉應力轉換成壓應力，可避免頸縮破裂等缺陷且提高機械性質。 本研究主要探討金屬毛細管之中間微旋鍛縮徑成形，首先透過DEFORM 3D有限元素法分析管材的中間縮徑製程，針對不同管徑的條件下，搭配不同的管壁厚度與外徑比以及縮徑長度與外徑比等二參數，探討在微旋鍛過程中外徑縮率對管壁厚度與等效應變之影響，並針對某些製程參數，進行微旋鍛件試樣。 模擬結果有以下結論：當外徑縮率較低時管件之管壁會有增厚的趨勢，然而當縮率較高時，則管壁會有薄化的趨勢，且最高達到約50%薄化率。模擬結果可得知管壁厚度外徑比與管壁薄化率是有相對的趨勢，當薄管縮徑旋鍛後其管壁薄化較為明顯，相對於厚管為較不顯著。 從實驗結果中發現，加工參數對產品品質有相當的影響，本機臺斜推桿為氣動控制，使鍛打行程無法微小增量，可透過手動工具改良為微動進給。當模具圓角過小時，會有咬料的情況發生，造成工件褶料堆積；模具圓角過大時容易造成胚料呈現多邊形的情形，此現象可與模擬預測中的圓角設計不當時所產生的缺陷相互驗證。因此為達到較好的表面粗糙度及成形外觀尺寸，除上述參數影響問題之外，其環境因素有如機臺震動及材料夾持不當時，會使工件出現偏心鍛打的現象，甚至會有壓扁及破裂等缺陷。
並列摘要
Currently most used metal capillary drawing process approach to the process of forming, when reduced to near micron size, the remaining material through the cavity of the wall dozens of grains is around this time to drawing process the process, the relationship between the size effect due to surface friction led to the relative increase in tensile stress will increase, easily lead to necking rupture. Therefore, through micro rotary swaging process instead of drawing process forming range can’t be overcome, by micro rotary swaging of forming characteristics, and more to small incremental forging, material can increase mechanical properties and uniform deformation through the conversion process and the at the same time, it will convert the tensile stress to compressive stress, to avoid the defects such as broken neck. This work aims to analyze the plunge-swaging process of pipe via finite element software DEFORM 3D. Under the three workpiece diameter configuration, namely 0.5, 1and 5 mm, the effects of thickness to diameter ratio and reduce diameter length diameter ratio on effective strain and wall thickness are investigated. The results has the following conclusion: When low reduce diameter of pipe wall thickness will be increasing trend, however, when the reduction rate is high, the wall will be the trend of thinning, and up to about 50% thinning rate. From the simulation results that diameter and wall thickness ratio of the rate is relatively thin trend, thus increasing the pipe wall thickness can reduce the thinning of the phenomenon. Experimentally results found that in addition to processing parameters on the product quality is important, the deviation from the center tube forging have a great impact, vibration and material reasons, such as improper clamping when the tube appear eccentric forging the phenomenon, it is easy to compression or even broken defect obtained.