- 學位論文
射出成形CAE分析應用於楔型導光板之研究
A Study of Wedge Shape Light Guide Plate with Injection Molding CAE Analysis
摘要
平面顯示器已朝向高畫質的趨勢發展，而導光板又是平面顯示器的背光模組中關鍵性之零組件之一，其功能是將光源均勻傳遞至顯示畫面，因此導光板在射出成形製程之品質控管就愈加重要。本研究利用射出成形CAE分析軟體Moldex3D R9.1探討11.6吋楔型導光板(wedge-shaped light guide plate, WSLGP)之品質特性，研究主題分為：(1)探討模具的澆口設計對於融膠充填與殘留應力之影響；(2)模具的冷卻水路佈置對導光板各軸向位移量之影響；(3)應用田口實驗方法及變異數分析，規劃射出成形參數的因子與水準，探討成形參數對導光板總位移之影響；(4)以優化的製程參數進行模擬分析，並藉信心區間計算加以驗證；(5)驗證實際射出導光板的充填狀態，並用偏光儀觀察殘留應力的分佈。 研究結果顯示，扇形澆口角度以不對稱設計，即12°_45°時，有助於減少充填產生的剪切生熱區域，因此能降低充填階段的殘留應力。循環冷卻水路設計在母模側水路中心距離分別在40, 35及30 mm時，對於導光板X、Y及Z三個軸向位移量的影響不明顯。公模側水路中心與分模面的距離分別為25, 20及15 mm，當距離愈小，Z軸向位移有增加的趨勢。因此建議採用水路中心間距35-40 mm，水路中心與分模面距離20-25 mm。 田口實驗方法分析結果顯示，在95％以上之信心指標，保壓壓力為影響導光板總位移最顯著因子，其次為融膠溫度，較高的高保壓壓力與較低的融膠溫度，能得到較小的導光板總位移量值。經由驗證實驗及信心區間計算結果顯示，原始與優化後製程參數之導光板總位移量值分別為2.86 mm及2.42 mm。藉由信心區間的計算，驗證出模擬分析結果與預測值是相當接近的。
並列摘要
Flat displayer is the trend of high quality of display today. Light guide plate (LGP) is critical element of the back light module in the flat displayer. The function of LGP is to transmit the light source to the display monitor. Therefore, the quality control of LGP in injection molding process is very important. In this study, Injection Molding CAE analysis software, Moldex3D R9.1 was used to research the quality characters of 11.6 inches Wedge-shaped light guide plate (WSLGP). The subjects of this study is：(1) The effects of mold gate design on the melt filling and residual stress. (2) The effects of the cooling pipes layout on the displacement of WSLGP at each axial direction. (3) The injection molding parameters affect on the total displacement of LGP by using Taguchi method and analysis of variance. (4) With Taguchi optimal processing parameter to simulate and analyze the results and verify by the calculation of confidence intervals. (5) Proving the filling state of practical injection LGP parts and with the polarized light apparatus examines the distribution of residual stress. Results show the shear-generated thermal area decreases when the fan gate designed with unsymmetrical, 12°_45°, and then the residual stress also decreases at filling phase. The center distance of cooling pipes designed under 40, 35, and 30 mm. We find the change of displacement value at X、Y and Z axes is not noticeable. The distance from parting line to the cooling pipes center was designed at 25, 20, and 15 mm. The displacement value at Z axis increases with the distance decreasing. So the center distance of cooling pipes is 35-40 mm and the distance from parting line to the cooling pipes center is 20-25 mm at this study suggestion. Results of Taguchi method analysis show the packing pressure is the most significant factor, the melt temperature is the next at 95% of confident index. Higher packing pressure and lower melt temperature will reduce the total displacement of LGP. Verification experiment and confidence intervals calculation show that the total displacement of LGP under the optimal process parameters is 2.42 mm. It is smaller than the 2.86 mm that of the original condition. By using the calculation of confidence intervals, the result of the verified simulation analysis is very close to that of the predicted value.