A method of manufacturing a molded part includes inserting melt into a cavity of a first tool part, and the first tool part and a second tool part are moved away from one another during or after the insertion of the melt by moving a mold clamping plate relative to a mold clamping plate such that in the first tool part or in a second tool part an at least partial clearance of a first or second zone of the cavity takes place, and a gap is formed between the first tool part and the second tool part. Melt is further inserted into the cleared area of the cavity, and the gap is bridged by an at least already partially solidified section of the melt. A holding force is transmitted from the second tool part through the partially solidified section of the melt bridging the gap to the first tool part.

A method that combines injection molding and extrusion is disclosed. First, a molten material is injected into a mold via an injection gate, the mold comprising a first portion and a second portion. Next, additional molten material is injected via the injection gate and pushed through an extrusion die located in the first portion of the mold and the second portion is separated from the first portion. In embodiments, the second portion is separated from the first portion before the additional material is injected. In other embodiments, the second portion is separated from the first portion simultaneously with the additional material being injected. The method may be used to produce longer and thinner parts with detailed features, such as catheters.

A molding apparatus includes a mold comprising a stationary outer mold with a substantially tubular mold cavity, a moveable end mold with an end mold cavity alignable with the tubular mold cavity, and a stationary elongated mold core with a fluid channel therethrough, the mold core extending through the tubular cavity into the end mold cavity. A method of using the apparatus includes injecting a molding material at a material flow rate into the mold, moving the end mold at a speed in a linear direction from a first position to a second position, supplying a fluid at a fluid flow rate to the fluid channel, and varying at least one of the material flow rate, the end mold speed and the fluid flow rate as the end mold moves from the first position to the second position.

In a stator injection molding centralization technique, a mold core is disposed inside a stator tube, thereby forming an annulus between the stator tube and mold core. The mold core includes a pitch length defined between a first and second lobe tip of the mold core. A centralizing member is positioned in the annulus, which has a length at least as long as the pitch length of the mold core. During the injection molding process, elastomeric material is injected into the annulus behind the centralizing member, which is located adjacent to the injection point. As the elastomer is injected, it displaces the centralizing member ahead of it along the annulus. As the centralizing member moves through the annulus, it supports the mold core, thus preventing the sag effect.

The present invention is a method and apparatus for molding plastic parts and placing and orienting reinforcing fibers within structurally thin sections. More specifically, the method of the present invention is a molding technique wherein positive displacement is applied to incremental sections of a charge (plastic mixed with reinforcing fibers), thereby sequentially forming the desired part and placing reinforcing fibers within structurally thin sections. The apparatus of the invention is a moveable ram that may be tapered and that is in contact with the charge during forming.

A mold assembly comprises a mold sidewall surrounding a mold cavity. A material inlet passageway, through which plasticized material may be introduced into the mold cavity, is formed in an inlet end wall of the mold. A sliding core is mounted within the mold and advanceable between a seated position covering the inlet passageway and a retracted position spaced away from the inlet passageway to allow plasticized material to flow into the mold cavity. An annular plunger is slidably mounted on the sliding core and within the mold sidewall for applying a downward force on plasticized material introduced into the mold cavity. Fiber reinforcing inserts may be inserted into the mold prior to filling it with plasticized material and a source of Nitrogen gas is connected to an extruder for purging ambient air from the plastic material in the extruder prior to injection into the mold cavity.

The present disclosure concerns an apparatus and a method for injection molding of an elongated hollow article, such as a urinary catheter, said apparatus comprising a heated central mold with an inlet opening for entering liquid molding compound into a substantially tubular cavity formed in said central mold; an elongated central mold core which is provided in the tubular cavity and extends beyond said tubular cavity and into a tip mold cavity of a tip mold part which is aligned with the tubular mold cavity in the longitudinal axis of the central mold core; wherein the tip mold part is moveable in a linear movement in a direction along the longitudinal axis of the elongated central mold core.