| 摘要 |
PROBLEM TO BE SOLVED: To obtain a core sufficiently enduring a high pressure die casting process and excellent in the workability by manufacturing the core from wooden fiber material as the main component. SOLUTION: The paper-made core 10 for forming an undercut parts 6 communicated with a bore 4 straightly extended in a casting 2, is provided with the core body for forming the bore 4 and the cores 16, 16 for forming the undercut part fitted to the core body 14 so as to be separatable with shearing force at the time of pulling out the core body 14. Since the core for forming the undercut is plural paper laminated bodies being separatable, after casting, the core is crushed to remove by giving the outer force or by heat-carburizing in an annealing process, etc. Further, the paper-made core 10 and the cores 16 for forming the undercut part are dissolved with solvent and crushed. Therefore, the removal of the core from a complicated piping difficult to approach from the outer part or a cavity having small opening hole, is facilitated.
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