| 摘要: | 本研究成功利用精密鑄造工藝做出AI伺服器液冷散熱系統的重要零件之一分歧管，該產品具高度細長比與薄壁幾何(長440*寬65*高35 mm，厚度2.5-4 mm )。原加工方式是將整塊板料加工需超過10小時，經精密鑄造做出鑄件再加工特徵只需1小時，節省90 %的加工時間，大幅提升加工效率。初期利用3D列印快速試樣得知方案可行性，試樣六種組樹方案後選出最佳方案為case 4。分歧管鑄件的主要變形Z軸方向及Y軸方向，經3D掃描比對結果顯示，case 4的Z軸方向的平均最大變形量為0.97 mm，優於case 5的3.21 mm，變形差異2.24 mm，Y軸方向平均最大變形量為0.3 mm。case 4方案的Z軸方向變形量較小，整形後的鑄件高度差優於case 5可控制在0.85 mm內，可以符合機械加工需求，並得知未來量產整型後的高度尺寸管制上限(UCL)為17.7 mm，管制下限(LCL)為16.9mm，以及控制線(CL)為17.24 mm。鑄件縮孔缺陷進行兩次改善，第一次改善縮孔比例從70 %降至45 %，第二次改善調整澆口位置及尺寸，並經加工後確認縮孔比例為0 %。觀察鑄件變形趨勢及整型後結果，以及鑄造的得料率、脫蠟殼裂狀況及縮孔改善情形，最佳方案為case 4並建議成為未來量產方案。;This study successfully applies precision investment casting to fabricate a manifold, one of the key components in an AI server liquid-cooling thermal management system. The product features a high aspect ratio and thin-walled geometry (length 440 mm, width 65 mm, height 35 mm, wall thickness 2.5–4 mm). Compared with the original process of machining the part from a solid plate, which required more than 10 h, the new route of producing a near-net-shape casting followed by local feature machining reduces machining time to 1 h, achieving a time saving of approximately 90% and significantly improving manufacturing efficiency. In the early stage, rapid prototyping by 3D printing was used to verify process feasibility, and six different tree assembly (gating) layouts were tested. Among these, case 4 was identified as the optimal scheme. 3D scanning and CAD model comparison show that the main distortion of the manifold casting occurs in the Z and Y directions. For case 4, the average maximum deformation in the Z direction is 0.97 mm, which is superior to 3.21 mm in case 5, corresponding to a difference of 2.24 mm; the average maximum deformation in the Y direction is 0.3 mm. Owing to the smaller Z-direction distortion in case 4, the height variation of the casting after straightening can be controlled within 0.85 mm, satisfying the subsequent machining requirements. Furthermore, for future mass production after straightening, the statistical process control limits of the height dimension are determined as an upper control limit (UCL) of 17.7 mm, a lower control limit (LCL) of 16.9 mm, and a center line (CL) of 17.24 mm. Shrinkage porosity in the castings was improved in two stages. The first optimization reduced the shrinkage porosity ratio from 70% to 45%. In the second optimization, by adjusting the gate positions and dimensions and confirming the internal quality after machining, the shrinkage porosity ratio was further reduced to 0%. Considering the casting distortion behavior, straightening results, casting yield, shell cracking during dewaxing, and shrinkage porosity improvement, case 4 is identified as the best scheme and is recommended as the layout for future mass production. |
