论文部分内容阅读
通过对壳型（芯）的成型试验和机理分析，提出了覆膜砂脱壳缺陷产生的主要原因是，在壳型（芯）成型过程中，覆膜砂的软化状态区厚度大，受重力及其它外力作用，软化区覆膜砂克服熔融树脂的粘结力而脱离固体型壳。降低覆膜砂脱壳缺陷的关键是减薄软化层的厚度，为此应选用具有较高熔点、较快结壳速度和较大热态强度与常温强度比值的覆膜砂。
Based on the forming test and mechanism analysis of the shell (core), the main reason for the occurrence of the delamination defects of the coated sand is proposed. During the forming of the shell (core), the thickness of the softened state zone of the coated sand is large, And other external forces, the softening zone coated sand to overcome the adhesive force of molten resin from the solid shell. The key to reduce the defects of shelling the coated sand is to reduce the thickness of the softened layer. For this purpose, the coated sand with higher melting point, faster crusting rate, and larger ratio of hot strength to room temperature strength should be selected.