| 摘要 |
PROBLEM TO BE SOLVED: To prevent the clogging of a gas venting hole and the lowering of jointing precision of a combined core by applying a coating material on the whole surface of the sand core after sticking a stick inhibitor for the coating agent to a position receiving the adverse effect with the coating material. SOLUTION: The material 30 having water repellency is stuck on the position receiving the adverse effect with the coating agent in the sand core 10, i.e., each of gas venting holes 12 so as not to stick the coating agent and thereafter, the coating agent is applied on the whole surface of the sand core 10. In the case of sticking the stick inhibitor 30 to the sand core 10, the opening part sides of the gas venting hole 12 in the sand core 10 are pressed to the solid stick inhibitor 30, and the sand core 10 is reciprocatedly moved. By this method, the stick inhibitor 30 is stuck in the state of closing the opening parts of the gas venting holes 12. Thereafter, the ordinary coating is executed to the surface of the sand core 10. By this method, the coating material is not stuck to the opening part of the gas venting hole 12 or is melted by drying heat and removed. |
