多齿芯头是制造微小型轴向内沟槽铜管( AIGCT) 的芯模，其齿的几何形状直接影响管内壁沟槽的成形质量及自身的寿命．文中根据单个齿成形区域的边界特征和AIGCT 成形时矩形齿横截面金相图上呈现的金属流动特点，将成形区域划分为刚性区Ⅰ、塑性变形区、刚性区Ⅱ以及两个被压实的死区; 使用上限法建立齿形成形的单位挤压力数学模型，并分析各参数对单位挤压力的影响机制，求解出金属最优流动方向的角度及其影响因素; 从而优化出多齿芯头的齿形参数．

The multi-tooth mandrel is used to machine the axially inner micro-grooved Copper tube ( AIGCT) ,and the geometric shape of the teeth directly affects the forming quality and the tool life. In this paper,based on both the characteristics of metal flow,which is presented by using the metallographic images of the rectangle tooth cross-section during the forming of AIGCT,and the boundary features of the forming zone of a single tooth,the forming zone is divided into four parts: rigid zoneⅠ,plastic deformation zone,rigid zone Ⅱand two compacted dead zones. Then,a mathematical model of the unit extruding force is established for the forming of tooth shape by means of the upper bound method,the mechanism of the process parameters affecting the unit extruding force is then analyzed,and the angle of optimal metal flow direction and the factors to influence the optimization are thus
solved. Finally,the parameters of tooth shape of the multi-tooth mandrel are optimized.