Universal single-row and multi-row insert stretch blow molding method and apparatus therefor

Method for the preparation of hollow thermoplastic articles in a stretch-blow-molding apparatus including a plasticizing unit, a robot with a universal gripper assembly, a preform-molding unit comprising a preform mold having a neck-ring clamp and an injection-core clamp, a conditioning unit, a stretch-blow-molding unit having a blow-core clamp, a stretch-rod clamp, and a stack blow-mold clamp with at least one row of blow-mold cavities, and a discharge unit, comprising the steps of

• (a) plasticizing raw material in the plasticizing unit to form a molten material,
• (b) transferring the molten material from the plasticizing unit into the closed preform mold of the preform-molding unit,
• (c) molding preforms in the preform-molding unit,
• (d) opening the neck-ring clamp of the preform-molding unit and introducing the robot with the universal gripper assembly in between the molded preforms during the preform-mold-clamp opening stroke,
• (e) picking up the resultant molded preforms with the universal gripper assembly of the robot simultaneously while opening the neck-ring clamp and opening of the injection-core clamp,
• (f) transferring the preforms with the universal gripper assembly of the robot to the conditioning unit;
• (g) closing the preform mold clamp assembly to start a new preform molding cycle,
• (h) conditioning the preforms in the conditioning unit,
• (i) transferring the preforms with the universal gripper assembly of the robot to the blow molding unit,
• (j) stretch-blow-molding the preforms in the blow molding unit in at least one row of blow-mold cavities into hollow articles,
• (k) transferring the hollow articles with the universal gripper assembly of the robot to the discharge unit,
• (l) releasing the finished hollow articles from the universal gripper assembly of the robot into the discharge unit, and
• (m) returning the universal gripper assembly of the robot to a waiting position at the preform-molding unit prior to completion of the preform-molding cycle, and
• (n) laterally moving the upper blow-mold clamp assembly on linear bearings to facilitate mold and tooling mounting.

Apparatus for producing finished hollow articles in a single and multi-row stack blow mold clamp including

• (a) a plasticizing unit for plasticizing raw material,
• (b) a preform molding unit having a frame clamp platen to mount neck-split holding bars adapted with neck splits at freely adjustable center-row distances in accordance with the equivalent preform-mold-center distances, the molding unit sliding on tie-bars between a fixed upper platen and a base machine platen,
• (c) a clamp platen housing mounted on the frame clamp platen which holds the clamp platen for the different rows of injection cores according to the center-distance rows of the neck split bars and neck splits,
• (d) a conditioning unit with a clamp platen and holding bars for mounting conditioning rods at freely adjustable center-row distances and heat-pots at center-row distances according to the equivalent preform-mold center-row distances,
• (e) a stretch-blow unit having a frame clamp platen to mount blow core holding bars with blow cores at freely adjustable center-row distances according to the equivalent preform-mold center distances sliding on tie-bars between a fixed upper platen and a base machine frame,
• (f) a frame housing mounted onto the frame clamp platen holding the clamp platen for the different rows of stretch rods according to the center-distance rows of the blow-core bars and blow cores,
• (g) a stretch-blow unit having a stretch rod and blow core assembly movable laterally on linear bearings to facilitate mold and tooling mounting,
• (h) a modular stack blow mold clamp assembly having a plurality of pivoting spacing means to open, close, hold, and align a multitude of blow mold halves with the corresponding blow core, stretch rod, and bottom plug rows according to the equivalent preform mold center distances,
• (i) a stack-blow-mold clamp assembly movable synchronously with a plurality of pivoting spacing platens and a multitude of stack-blow-mold halves which maintain the corresponding center row distances of the external means entering the blow-mold cavities during operation,
• (j) a multitude of spacing platens variable in size according to the desired stack-blow-mold cavity opening strokes,
• (k) a multitude of spacing platens variable in number according to the desired number of blow-mold cavity rows,
• (l) an oriented discharge unit to release finished hollow articles,
• (m) a robot having a universal gripper assembly and opening and closing means to pick up molten preforms during the clamp opening stroke of the preform mold unit and to guide the preforms through a multitude of processing units which transform the preforms into finished hollow articles and releasing them onto an oriented discharge unit,
• (n) the robot having a pivotable universal gripper assembly and opening and closing means to pick up molten preforms from a lateral preform preparing unit,
• (o) a second robot having a universal gripper assembly to pick up pretreated hollow articles and guide them into secondary blow mold units for transformation into finished hollow articles prior to release onto an oriented discharge unit,
• (p) a component transfer device assembly to pick up external components from dispensing cartridges and release them into open blow mold cavities simultaneously during other processing phases,
• (q) a component inserting unit to place internal components inside molten preforms prior to completion of their shrinkage phase, and
• (r) a component-inserting unit to place internal liners inside molten preforms to form a multi-layer hollow article, all processing units being independently turnable in relation to each other to minimize the number of universal gripper assemblies and to speed up the mold change-over procedure.