如图1所示,一般来说,铰链的弯曲过程是:先预弯头部,然后卷圆成形。 实践证明:在预弯时,由于材料外层金届受拉,内层金属受压,使得材料变薄,中性性层内移,即图1(b) 中部分。而在铰链的卷圆过程中,由于材料受到挤压和弯曲的复合作用,使得材料增厚,中性层外移,即图1 (b)中部分。无论中性层内移 As shown in Figure 1, in general, the hinge bending process is: pre-bending the head, and then round shape. Practice shows that: in the pre-bending, due to the material of the outer layer of gold tension, the inner metal pressure, making the material thinning, the neutral layer shift, that part of Figure 1 (b). In the process of reeling the hinge, the material is thickened and the neutral layer is displaced due to the compound effect of extrusion and bending, that is, the part in FIG. 1 (b). No matter Neutral layer shift