| 摘要 |
A mold for molding an information record having a relatively large diameter hole therethrough includes upper and lower mold members movable toward and away from each other. The upper mold member has a hole-forming pin extending therethrough and slidable therein. The pin has a recess in its end surface which faces the lower mold member. The recess has in a surface thereof at least one re-entrant which forms a lip. In molding a record, a plastic preform is placed between the mold members. The heated mold members are closed against the preform causing the plastic material to flow outwardly and fill the cavity between the mold members. The hole-forming pin is pushed through the plastic material with some of the plastic material filling the recess to form the hole in the record. When the mold members are separated the plastic material in the recess in the pin is retained in the recess by the lip.
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