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| 題 名 | 頂針式噴頭設計應用於無機水玻璃3D列印砂模=The Needle-typed Printhead Design Applied for 3D Printing Sand Mold Using Inorganic Sodium Silicate Resin |
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| 作 者 | 賴立民; 許富淵; 賴立民; | 書刊名 | 鑄造工程學刊 |
| 卷 期 | 43:1=172 2017.03[民106.03] |
| 頁 次 | 頁7-20 |
| 分類號 | 472.22 |
| 關鍵詞 | 頂針式噴射閥; 3D列印砂模; 水玻璃樹脂; 砂模; Needle-type dispenser; 3D printing sand mold; Sodium silicate resin; Sand molds; |
| 語 文 | 中文(Chinese) |
| 中文摘要 | 水玻璃砂模具有高耐熱性,相較於有機樹脂砂模(例如:呋喃樹脂、酯類樹脂)較無氣體產生,能夠應用於高溫鑄件的砂模製作,(例如:不鏽鋼鑄件、高耐熱排氣管、渦輪增壓器殼等等)。而3D列印砂模具有一體成形之特性,可產出複雜之砂模,例如:模型無須導角、砂心無須組合等。目前3D列印的噴頭型式是以壓電材料為主,噴頭可以噴發較低黏度的液體例如水和Furan樹脂。但是,水玻璃黏度大於Furan樹脂的25倍,無法利用壓電方式擠出,因此本研究改用頂針式擠壓,設計一系列實驗,進行頂針式噴頭(needle-type dispenser)之設計,透過此設計實現水玻璃噴射並應用於3D列印砂模工業。本研究利用計算流體力學軟體數值模擬,通過壓力校正與模擬頂針通過給定之速度向下擠壓水玻璃,使水玻璃受壓後從噴嘴噴射之過程。藉由改變不同的頂針下壓速度(Vd)、頂針初始距離(Gi)、頂針與噴腔間的間隙(Ws)等參數等等,以觀察液滴噴射時,其體積和形狀的變化,以及了解進料壓力(Pf)與填充所需時間之關係。模擬結果發現,若要使液體不會在噴頭處自動流出並達一平衡,進料壓力(Pf)需為101.73 kPa;液體從噴嘴噴射的液滴加速度會隨頂針位移速度(Vd)變大而增加;當頂針與噴腔的間隙(Ws)增加至臨界值1.375(mm)時,最小液滴噴射出的加速度隨之減小(最小值為0.06 m/s^2),而且液滴體積隨之減小(最小體積0.86 mm^3);但當噴腔間隙(Ws)超過臨界值1.375mm時,液滴體積會突然上升而後趨於一定值,其值的大小受頂針初始距離影響;當頂針初始距離(Gi)增加時,液滴體積會隨之增加,但液滴噴發時的加速度越小:當進料壓力大於421.51(kPa)時,頂針回復原位後即可進行第二次噴射。若Ws間隙寬度控制於1.375mm以內時,可以得到本研究最小噴射之液滴半徑為0.27 mm,其體積為0.086mm^3。 |
| 英文摘要 | As casting high melting point metal (e.g., stainless steel casting, heat resistant outtake manifold casting, turbo charger housing casting, and etc. ), sodium silicate (water glass) sand molds is normally applied. This is because it has greater heat resistance strength and has lower gases emission comparing to organic resin bonded sand mold, such as Furan and phenolic resins. In 3D printing sand mold technology, sand mold with complicated casting geometry (e.g., casting geometry without tapering and sand cores without assembling) can be produced. However, current sand mold printing facilities use Furan resin to print mold. This is because they use piezoelectric print head, which can be used for low viscosity of liquid such as water and furan resin. The viscosity of sodium silicate resin is 25 times greater than that of Furan. Therefore, in this study, a needle-type dispenser method is applied to design printhead. The purpose of this study is to design a needle-typed printhead, which can be applied in 3D printing sodium silicate resin for sand mold industry. Commercial computational fluid dynamics (CFD) package was used to model the process of the water glass droplet coming out from the designed printhead. Various injecting parameters and dimensions of the needle-typed printhead, such as down velocity of needle (Vd), the initial needle gap (Gi), nozzle length (Ln), and the gap between needle and printhead chamber (Ws), were tested in order to observe the changes of volume and shape of the injecting droplets. The modeling results showed that the pressure of feeding resin (Pf) in the ingate should keep within 101.730 kPa for avoiding the leaking in the nozzle of printhead. Also, the acceleration of droplet becomes larger with increasing the needle down velocity (Vd). As the gap between needle and chamber (Ws) increases the acceleration of droplet decreases (e.g., the minimum value of 0.06 m/s^2) and droplet volume reached in minimum value of 0.86 mm^3, until the gap is in the critical of 1.375 mm . Over this critical gap, the acceleration jumps up to a high plateau value, which is dependent on the initial Gi value. As initial needle gap (Gi) increases the droplet volume increase but the droplet acceleration decreases. If the gap (Ws) is controlled within the critical, the smallest droplet volume of 0.086mm^3, which is the radius of 0.27(mm), is achieved. |
本系統中英文摘要資訊取自各篇刊載內容。