本文透過有限元素軟體Deform-3D進行擠壓絲攻成形模擬分析，探討M1.2螺絲攻應用於鋁合金7075之攻牙品質，其刀具幾何特徵對於內螺紋牙型填充率及最大扭矩的影響。因此，本文設計之刀具幾何參數包含四面寬、根徑、前端外徑及牙山角度，並利用實驗之內螺紋輪廓與牙型填充率進行模型驗證，確認有限元素分析模型之妥適性。為了分析多因子的品質問題，實驗設計採用適合建構二階反應曲面之Box-Behnken四因子三水準設計，總計25組模擬實驗。經由統計軟體Minitab針對模擬結果進行變異數分析，以建立牙型填充率及最大扭矩之迴歸預測模型，進而探討各因子對品質特性之影響，並找出最佳之刀具設計，達到提升填充率與降低最大扭矩之目的。另外，以有限元素模擬結果對本文所建構之預測模型進行檢驗，其結果顯示預測模型具有足夠的準確度，期望可協助業界於刀具研發之設計改善。;This study presents a finite element model of forming tap based on the Deform-3D software. Investigating the thread quality of M1.2 tap on 7075 aluminum alloy, and the influence of tool geometric parameters on the thread fill rate and maximum torque. Therefore, the factors of tool geometry, including tool width, root diameter, front-end diameter, and tooth angle. The result of experiments of internal thread profile and thread fill rate as validation of simulations. Its show that finite element model can deal with internal thread problem. 25 sets of simulation experiments are designed to three levels of each factor according to Box-Behnken design, a type of second-order response surface methodology. Analysis of variance(ANOVA) based on the simulation results established the regression equation of thread fill rate and maximum torque by using Minitab software. Depend on the effect of factors with tool geometry, find out the optimal design to increase thread fill rate, and reduce maximum torque in the thread process. Furthermore, the FEM simulation result has been validated by the regression equation, and establish the analysis model has certain accuracy on the internal thread process. This analysis model is expected to support an optimal tool design for the industry.
