Method of making a plurality of optical record disc substrates
AssigneeTDK Corporation
InventorsSeiki Shimazu, Kenji Yamaga, Yoshimi Sakai, Atsushi Koyama, Yuichi Namikawa
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Abstract
A method of making a plurality of optical record disc substrates includes the steps of injecting a resin material into a plurality of disc-shaped cavities which are formed by closing a fixed mold half and a movable mold half; and cooling the injected resin material in the cavities. The cavities are grouped into a plurality of groups so that each group includes not less than one cavity, and each group is provided with a common actuation device so that each actuation device is independently operated.
Claims3
A method of making a plurality of optical record disc substrates, the method comprising the steps of:
- forming a plurality of disc-shaped cavities by closing a fixed mold half and a movable mold half, wherein the cavities are grouped into a plurality of groups so that each group includes at least one cavity, and a fixed mold half and a movable mold half is associated with each of said groups;
- providing each of said groups with an independently operable hydraulic actuation means;
- injecting a resin material into the plurality of disc-shaped cavities;
- independently controlling each of said actuation means during said injecting step to actuate a corresponding movable mold half so as to permit a uniform injection of the resin material in each one of said cavities;
- cooling the injected resin material in the cavities;
- and
- independently controlling each of said actuation means during said cooling step to compensate for shrinkage of the resin material during said cooling step.
Dependencies are inferred from the claim text.