PRODUCTION OF MOLD FOR PRECISION CASTING

摘要

PURPOSE:To improve the dimensional accuracy of a casting mold and to reduce the cost thereof by using an org. self-curing process. CONSTITUTION:A self-curable resin such as a furan no-bake resin or the like is used as a binder. Silica sand or the like having 150-350 mesh grain size is used as aggregate and a zircon flower is added at about 10-30% thereof if there is a requirement for a casting surface. The aggregate is charged to a sand mixing mill and a curing agent is added thereto, then the materials are kneaded for about 60-180sec. Then a furan no-bake resin is added thereto at about 1-3% of the aggregate and the materials are kneaded for 60-180sec. Molding is accomplished in a case iron flask or the like by manpower or an oscillating table. Curing is completed in 20-120min after completion of molding and therefore the mold is removed by a crane or the like and a water diluted colloidal graphite is coated thereon and is dried, by which a casting mold is obtd. There is no thermal deformation owing to the calcination of the casting mold and therefore the dimensional accuracy is improved. The equipment cost is low and since inexpensive gypsum, etc. are usable for the model mold, the cost is considerably reduced.