Method for simultaneous injection and compression
OwnerDale Groveinventor
Life of this patent
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Abstract
Method and apparatus for molding an article by forming an oversized mold cavity with respect to opposing relatively movable mold members, introducing material into the oversized mold cavity and applying force to the mold members to reduce the volume of the cavity and compress the material simultaneously with its introduction into the mold cavity. The result is simultaneous injection and compression of material by contrast with the prior art of simultaneous injection and volume reduction, where compression does not take place until after injection has been completed.
Claims16
A method of forming an article having a prescribed volume and mass from a material using a molding machine, comprising the steps of:
- (a) forming an oversized mold cavity with respect to an opposing pair of relatively movable mold members of said molding machine between which mold members said article is formed;
- (b) introducing into said oversized mold cavity a volume of material exceeding the prescribed volume of the article to be formed and having a mass at least equal to the prescribed mass of the article;
- (c) applying force to said mold members to reduce a volume of said mold cavity and compress said material therein simultaneously with its introduction thereby to form said article.
A method of forming a plurality of articles from a moldable material using a molding machine having first and second mold platens, first and second mold members, each having a corresponding plurality of mold structures, comprising:
- (a) forming a plurality of pre-enlarged mold cavities by adjusting relative positions of opposing mold members, at least one of which is capable of movement relative to the other, said mold cavities having dimensions determined by distance between the platens, and said members initially being separated to form pre-enlarged cavities with volumes each greater than a maximum volume occupied at atmospheric pressure by the moldable material to be introduced into the cavity;
- (b) introducing into each pre-enlarged mold cavity a volume of moldable material larger than a volume of the article to be formed but insufficient to fill each pre-enlarged cavity;
- (c) commonly and simultaneously applying a main clamp force of the molding machine before commencement of said injection to reduce the volumes of the mold cavities and fill the reduced-volume mold cavities;
- and
- (d) maintaining the applied main clamp force until a final clamp lock-up position is reached, thereby compressing the material until a slight excess is forced into a pressure relief outlet and the material solidifies.
Dependencies are inferred from the claim text.