多单位整铸固定桥精度的研究

A Study of Accuracy of Multiple-Unit One-Piece Castings of Fixed Bridge

作者研究了三种不同浇注方案和热处理对三单位、四单位固定桥精度的影响。实验结果表明:①两类固定桥的精度,均以顶端侧注方案较高。②铸件热处理后,应力重新分布,而精度降低。③从固定桥的总长度和桥体长度尺寸变化看,多单位桥普遍出现“岔口状”变形。

We studied how the accuracyof the three-unit and four-unit bridges isaffected by the three different sprue pro-grammes and heat-treatment. The resultsof experiments are as follows. 1. In the two types of fixed bridge theaccuracy of the lateral pouring sprue pro-gramme is greater than that of the top-pouring and bottom-pouring sprue pro-grammes.2. After the heat-treatment of the cast-ing, the stresses are distributed again, sothe accuracy of the casting becomes lesser.3. The change in the measurement ofthe total and pontic lengths of multiple-unit fixed bridges generally causes a 'forkshape' deformity.