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US 4,427,618 AGranted
Inclined insulated runner multicavity injection molding
OwnerJens O. Sorenseninventor
Life of this patent
Estimating the term…
Abstract
A system and a method of multicavity injection molding of a product, where the gate cannot be placed, as traditionally, at the top of the product, but must be placed at the side of the product; this is accomplished by using inclined secondary runners; the process is exceedingly fast since the secondary runners are not heated in their basic form; disclosed is also the method and means for employing polystyrene as the injection molding material.
Claims6
A method of cyclic multicavity plastic injection molding, wherein the employed mold comprises a product parting surface and a runner parting surface which is different from the product parting surface, and wherein each normal production cycle comprises the steps of:
- (a) injecting a hot molten plastic into a primary runner system of a multicavity mold;
- (b) directing the injected plastic through the primary runner system to some inclined secondary runners, which are positioned in the runner parting surface, and which connect the primary runner system with some restriction gates;
- (c) leading the directed plastic through the inclined secondary runners to the restriction gates which directly connect the inclined secondary runners with the chilling cavities;
- (d) cooling the led plastic in the inclined secondary runners by transferring heat from the plastic to the walls of the inclined secondary runners which have a temperature which is lower than the temperature of the led plastic in a manner so that the plastic in the inclined secondary runners does not solidify in their entire cross-sectional region but remains molten in a central zone of their cross-sectional region;
- (e) conducting the led cooled molten plastic through the restriction gates into the chilling cavities;
- (f) cooling the conducted plastic in the chilling cavities by the cavity cooling system whereby the cooled plastic solidifies thereby creating a molded product;
- and
- (g) separating the mold at the product parting surface and ejecting the molded product from the chilling cavities, which are positioned in the product parting surface, without ejecting any runner plastic impression;
- wherein when the normal production cycle is terminated, the led molten plastic within the inclined secondary runners transfers additional heat to the walls of the inclined secondary runners whereby the led molten plastic solidifies throughout its entire cross-sectional region;
- the method additionally comprising the following steps for reestablishing the normal production cycle following such termination:
- (h) separating the mold at the runner parting surface in order to expose the solidified impressions of the inclined secondary runners;
- (i) removing the solidified impressions of the inclined secondary runners in such a manner that the impressions of the restriction gate on the solidified impression of the inclined secondary runners are removed through the inclined secondary runners in a direction which is not parallel to the mold opening direction;
- and
- (j) recombining the mold at the runner parting surface which contains the inclined secondary runners.
11 more elements
A method of cyclic multicavity plastic injection molding, wherein the employed mold comprises a product parting surface and a runner parting surface which is different from the product parting surface, and wherein each normal production cycle comprises the steps of:
- (a) injecting a hot molten plastic into a primary runner system of a multicavity mold;
- (b) directed the injected plastic through the primary runner system to some inclined secondary runners, which are positioned in the runner parting surface, and which connect the primary runner system with some restriction gates;
- (c) heating at least a region of the walls of the primary runner system in order to reduce or prevent heat loss from the directed plastic to the region of the walls of the primary runner system;
- (d) leading the directed plastic through the inclined secondary runners to the restriction gates which directly connect the inclined secondary runners with the chilling cavities;
- (e) cooling the led plastic in the inclined secondary runners by transferring heat from the plastic to the walls of the inclined secondary runners which have a temperature which is lower than the temperature of the led plastic in a manner so that the plastic in the inclined secondary runners does not solidify in their entire cross-sectional region but remains molten in a central zone of their cross-sectional region;
- (f) conducting the led cooled molten plastic through the restriction gates into the chilling cavities;
- (g) cooling the conducted plastic in the chilling cavities by the cavity cooling system whereby the cooled plastic solidifies thereby creating a molded product;
- and
- (h) separating the mold at the product parting surface and ejecting the molded product from the chilling cavities, which are positioned in the product parting surface, without ejecting any runner plastic impression;
- wherein when the normal production cycle is terminated, the led molten plastic within the inclined secondary runners transfers additional heat to the walls of the inclined secondary runners whereby the led molten plastic solidifies throughout its entire cross-sectional region;
- the method additionally comprising the following steps for reestablishing the normal production cycle following such termination:
- (i) separating the mold at the runner parting surface in order to expose the solidified impressions of the inclined secondary runners;
- (j) removing the solidified impressions of the inclined secondary runners in such a manner that the impressions of the restriction gate on the solidified impression of the inclined secondary runners are removed through the inclined secondary runners in a direction which is not parallel to the mold opening direction;
- and
- (k) recombining the mold at the runner parting surface which contains the inclined secondary runners.
12 more elements
Dependencies are inferred from the claim text.