摩潤模式對曲線模擠製最佳化的影響

A Realistic Friction Model for Optimal Shape of Extrusion Processes

徐偉真(Wei-Chen Hsu)

指導教授 ： 徐澤志 ； 洪景華

元智大學/工程學院/機械工程學系/碩士(2000年)

摘要

最佳化模具外型可節省擠製過程中所需的擠製力，使擠製過程更順利。而在擠製過程中，工件與模具之間的真實摩擦需藉由內在因子，例如：油膜厚度、表面粗糙度及潤滑油性質來分析。因此，本論文針對不同的潤滑狀況，根據最佳化的概念，結合最佳化軟體與擠製成形剛塑性有限元素法來分析最佳化的模具外型。
本研究將潤滑油性質與組合表面粗糙度做為設計參數，探討在這兩個摩潤因子下，最佳化外型的變化，得知這些因子皆會影響到模具的外型。最後為了驗證分析之結果，因此作一實驗與所得之數值結果作一探討與比較。

關鍵字

最佳化 ； 擠製過程 ； 有限元素法 ； 潤滑油 ； 表面粗糙度

並列摘要

The optimal shape can minimize the load in extrusion processes and facilitate the operation. The calculation of the realistic friction force between the workpiece and die must take into account of several interface factors, such as lubricant film thickness, workpiece roughness, tooling roughness and the lubricant property. The "optimal shape", can then be obtained by using the combination of rigid-plastic finite element code, realistic friction model and optimization software. In order to verify the realistic friction model, several lubrication conditions were considered ranging from full film lubrication to boundary lubrication.
In present investigation, the properties of lubricant, workpiece roughness and tooling roughness were taken as design parameters for studying the change of optimal die-shape. Finally, the comparison between the simulation and experiment agrees very well with each other and thus validate the proposed approach for optimal shape of extrusion processes.

並列關鍵字

optimization ； extrusion processes ； finite element code ； lubricant ； workpiece roughness ； tooling roughness

參考文獻

1.W. R. D. Wilson, “Friction and Lubrication in Bulk Metal-Forming Processes”, J. Applied Metalworking, Vol.1, pp.7-19, 1979.

2.N. Patir and H. S. Cheng, “An Average Flow Model for Determining Effects of Three-Dimensional Roughness on Partial Hydrodynamic Lubrication”, Journal of Lubrication Technology, Vol.100, pp.12-17, 1978.

3.N. Patir and H.S. Cheng, “Application of Average Flow Model to Lubrication Between Rough Sliding Surfaces”, Journal of Lubrication Technology, Vol.101, pp.220-230, 1979.

4.W. R. D. Wilson and S. Sheu, “Real Area of Contact and Boundary Friction in Metal Forming”, Int. J. of Mech. Sci., Vol. 30, No. 7, pp.475-489, 1989.

5.W. R. D. Wilson, “Mixed Lubrication in Metal Forming”, Advanced Technology of Plasticity, pp.1667-1675, 1990.