基于矢量夹角的开口结构塑件翘曲预变形补偿研究

Research on Warpage Pre-deformation Compensation of Plastic Parts with Opening Structure Based on Vector Angle

在现有预变形设计方法的基础上,提出基于矢量夹角及矢量夹角变化率来对翘曲变形区域进行二次划分,实现了翘曲变形区域的精准定位,克服了预变形设计起始点不精确、设计区域过大的缺点。首先,通过有限元模拟的方法获得翘曲变形后的产品模型;然后结合翘曲变形情况及零件关键尺寸位置来确定主面;再通过U、V等参曲线将翘曲变形前后主面的面特征转化为曲线网络,将曲线网络转化为点阵,并以该点作为测量点;通过UG二次开发程序来获得测量点的矢量值,并使用Matlab计算出矢量夹角并求得矢量夹角变化率,借此确定产品翘曲变形的区域;随后对翘曲变形区域内的部分进行反向补偿变形设计,并将非翘曲变形区域与其平顺连接即可获得预变形后的主面;最终通过产品图纸中各尺寸间与主面的相对关系,即可获得预变形产品。

Based on the existing pre-deformation design method,the further division of warped deformation area was proposed by the vector angle and change rate of vector angle,which realized the accurate positioning of the warped deformation area and overcomed the shortcomings in current pre-deformation design including inaccurate starting point and excessive design area.First,the product model after warpage deformation was obtained through finite element simulation method;second,the main surface was determined by combining the warpage deformation and the key size and position of the part;next,the surface feature of main surface before and after warpage deformation was converted into a curve network using the U and V isoparametric curves,and the dot matrix converted from the curve network was used as the measurement point;the vector value of the measurement point was obtained through the secondary development program of UG,and the vector angle and corresponding change rate were calculated by Matlab to determine the area of the warped deformation;then,the reverse compensation deformation design was carried out on the warped deformation area,and the deformation area without warpage was smoothly connected with it to obtain the pre-deformed main surface;finally,the pre-deformed product could be obtained on the basis of the relative relationship between the dimensions in the product drawing and the main surface.