Injection molding apparatus operating without opening the mold to airborne contaminants

An apparatus for injection molding plastic articles, comprising:

• a. a horizontal injection molding machine having means for controllably applying clamping force and motions between a stationary platen and a movable platen, means fo injecting molten plastic, said means for applying clamping and said means for injecting responding in accordance to a programmable machine process controller's sequence;
• b. a mold cavity within a moldset clamped between the stationary and movable platens,
• the mold cavity having A and B moldhalf sides with corresponding A and B partforming surfaces on either side of a parting line at a first vertical plane within the mold cavity when the moldset is in a first position wherein the mold cavity is closed at an outside perimeter against fluid communication with ambient air external to the moldset,
• and the A moldhalf side housing the A partforming surface, said A moldhalf side being held to the stationary platen and the B moldhalf side housing the B partforming surface, said B moldhalf side being held to the movable platen, with the B partforming surface having means for slidably advancing forward or retracting back within the B moldhalf side according to motions of the movable platen, such that when the moldset is in the first position a first distance separates the A and B partforming surfaces on either side of the first vertical plane, and a second position of the moldset is reached by the motions of the movable platen, thereby moving the B partforming surface to a second vertical plane, at which second position the A and B partforming surfaces are separated by a second distance which is greater than the first distance,
• and the mold cavity in the second position is closed at the outside perimeter except for an aperture located in the second plane;
• c. means for selectively adhering the molded plastic article onto one of the partforming surfaces during movement from the first position to the second position, and means for transferring the molded article off the partforming surface at the second position through the aperture out of the moldset;
• d. means for pressurizing the mold cavity internally with pressurized filtered gas from a supply external to the moldset, so as to maintain a positive pressure higher than ambient air pressure at least when the second position is reached, so as to preclude upwelling convective air currents from below the mold cavity contacting the partforming surfaces therein.

An apparatus for injecting molding plastic articles, comprising:

• a. a horizontal injection molding machine having means for controllably applying clamping force and motions between a stationary platen and a movable platen, means for injecting molten plastic, said means for applying clamping and said means for injecting responding in accordance to a programmable machine process controller's sequence;
• b. mold cavity within a moldset clamped between the stationary and movable platens,
• the mold cavity having A and B moldhalf sides with corresponding A and B partforming surfaces on either side of a parting line at a first vertical plane within the mold cavity when the moldset is in a first position wherein the mold cavity is closed at an outside perimeter against fluid communication with ambient air external to the moldset,
• and the A moldhalf side housing the A partforming surface, said A moldhalf side being held to the stationary platen and the B moldhalf side housing the B partforming surface, said B moldhalf side being held to the movable platen, with the B partforming surface having means for slidably advancing forward or retracting back within the B moldhalf side according to motions of the movable platen, such that when the moldset is in the first position a first distance separates the A and B partforming surfaces on either side of the first vertical plane, and a second position of the moldset is reached by the motions of the movable platen, thereby moving the B partforming surface to a second vertical plane, at which second position the A and B partforming surfaces are separated by a second distance which is greater than the first distance,
• and the mold cavity in the second position is closed at the outside perimeter except for a downward facing aperture whose center is located below a centerline of the mold cavity in the second plane;
• c. means for selectively adhering the molded plastic article onto one of the partforming surfaces during movement from the first position to the second position, and means for transferring the molded article off the partforming surface at the second position through the downward facing aperture out of the moldset;
• d. means for pressurizing the mold cavity internally with pressurized filtered gas from a supply external to the moldset, so as to maintain a positive pressure higher than ambient air pressure at least when the second position is reached, so as to preclude upwelling convective air currents from below the mold cavity contacting the partforming surfaces therein.

An apparatus for injection molding plastic articles, comprising:

• a. a horizontal injection molding machine having means for controllably applying clamping force and motions between a stationary platen and a movable platen, means for injecting molten plastic, means for controllably moving an ejector assembly forward or backward, said means for applying clamping and said means for injecting responding in accordance to a programmable machine process controller's sequence;
• b. a mold cavity within a moldset clamped between the stationary and movable platens,
• the mold cavity having A and B moldhalf sides with corresponding A and B partforming surfaces on either side of a parting line at a first vertical plane within the mold cavity when the moldset is in a first position wherein the mold cavity is closed at an outside perimeter against fluid communication with ambient air external to the moldset,
• and the A moldhalf side housing the A partforming surface, said A moldhalf side being held to the stationary platen and the B moldhalf side housing the B partforming surface, said B moldhalf side being held to the movable platen, with the B partforming surface having means for slidably advancing forward or retracting back within the B moldhalf side according to motions of the ejector assembly, such that when the moldset is in the first position a first distance separates the A and B partforming surfaces on either side of the first vertical plane, and a second position of the moldset is reached by the motions of the ejector assembly, thereby moving the B partforming surface to a second vertical plane, at which second position the A and B partforming surfaces are separated by a second distance which is greater than the first distance,
• and the mold cavity in the second position is closed at the outside perimeter except for a downward facing aperture whose center is located below a centerline of the mold cavity in the second plane;
• c. means for selectively adhering the molded plastic article onto one of the partforming surfaces during movement from the first position to the second position, and means for transferring the molded article off the partforming surface at the second position through the downward facing aperture out of the moldset;
• d. means for pressurizing the mold cavity internally with pressurized filtered gas from a supply external to the moldset, so as to maintain a positive pressure higher than ambient air pressure at least when the second position is reached, so as to preclude upwelling convective air currents from below the mold cavity contacting the partforming surfaces therein.