| 摘要 |
A system of making molds for investment casting in which the patterns are formed from, and the sprue form is coated with, polyethylene glycol having a molecular weight in the range of from approximately 1,300 to approximately 1,600, or its equivalent and having admixed therein as a filler powdered graphite, in which the graphite comprises in the range of from about 35 per cent to 60 per cent by weight of the pattern forming material. The patterns are molded to the desired shape, and to include a gate section, and they are adhered to the sprue form in spaced apart relation by fluidizing the gate section end to make a welded connection with the sprue form coating. The mold is then formed about the patterns that are adhered to the sprue form, leaving the pour cup end of the sprue form exposed, to which heat is subsequently applied to sufficiently fluidize the sprue form coating so that the sprue form can be drawn out of the mold thereby leaving the sprue opening. The sprue form coating remaining in the mold sprue and the patterns are then removed without heating the mold by leaching with water, utilizing mechanical and/or chemical agitating after which the mold may be heated sufficiently to dry same for use as an investment casting mold.
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