摘要
目的研究包埋材料热膨胀率和凝固膨胀率变化对铸件铸造精度的影响。方法采用预制标记点的圆盘形蜡型,用同一种铸圈、2种石膏基包埋料,其总膨胀率相似,但一种具有高的热膨胀率,另一种具有高的凝固膨胀率,选用0.7mm厚的陶瓷纤维铸圈衬层对蜡型进行包埋铸造,测量相应标记点方向上铸件与蜡型的尺寸变化,研究包埋材料热膨胀率和凝固膨胀率变化对铸件铸造精度的影响。结果在本实验研究范围内,包埋材料所铸造的铸件轴向方向膨胀均大于径向方向膨胀。高热膨胀率包埋料包埋的铸件各方向尺寸变化有统计学意义(P<0.05),而高凝固膨胀率包埋料包埋的铸件各方向尺寸变化无统计学意义(P>0.05)。2种包埋料对铸件铸造精度的影响均有统计学意义(P<0.01)。结论石膏基包埋材料热膨胀率和凝固膨胀率的变化对铸件的铸造精度有影响。在有圈衬层包埋时,应选用凝固膨胀率高的包埋料。
Objective To investigate the effect of difference between thermal and setting expansion rate of the investments on the deformation of resulted castings. Methods Plate-like wax patterns with pre-marked points were invested in two different gypsum-bonded investments of the same total expansion rate. One was higher in setting expansion rate, while the other was higher in thermal expansion rate. Casting rings were lined with a dry ceramic fiber liner by thickness of 0.7 mm. The difference between the castings and the wax patterns at corresponding points were calculated to represent the dimensional changes of the investments with different thermal and setting expansion rate in the rings at different directions. Results In the scope of this study, the casting expansions of the two investments on the axial direction were larger than the radial direction. The difference between the cast and the wax created by higher thermal expansion rate investment on each direction was statistically significant （P〈0.05）, while higher setting expansion rate investment was not statistically significant （P〉0.05）. Effects of two investments on the precision of castings were statistically significant（P〈0.01）. Conclusion The two gypsum-bonded investments with different thermal and setting expansion rate have effect on the casting precision. The investment with higher setting expansion rate should be applied when invested with liner in the casting rings.
出处
《国际口腔医学杂志》
CAS
2009年第5期531-534,共4页
International Journal of Stomatology
关键词
石膏基包埋料
热膨胀
凝固膨胀
铸造精度
gypsum-bonded investment
thermal expansion
setting expansion
casting precision
