HK1038331B - Compact post-mold cooling device - Google Patents

Description

Small-sized post-mold cooling device

Technical Field

The present invention relates to a method and apparatus for multi-stage, post-ejection temperature conditioning, i.e., cooling or cooling and reheating or simply reheating, for use with a plastic injection molding machine having significant cycle times and high throughput.

Background

In the case of molding molded articles in large quantities, reducing the injection molding cycle time is a major task. This is the case, for example, in the case of PET preforms made using high density cavity molds, such as 72 or 96 cavity molds produced by Husky Injection Molding Systems. One option to reduce the injection molding cycle time is to limit the residence time of the preform in the mold closed position by shortening the cooling step by a few seconds and removing the preform from the mold very quickly. The temperature gradient across the preform wall indicates that the skin layers on the inside and outside of the preform are at a lower temperature than the middle layer. This is because: in the mold closed position, cooling occurs at both the mold cavity and the mold core.

In the past, various efforts have been made in the prior art to improve the post-forming cooling process when forming PET preforms. For example, US4209290 to Rees et al describes a system in which preforms or parisons to be blown into bottles are required to be formed in cavities of lower mold halves of a vertical injection molding machine when the mold is closed by means of respective cores that penetrate from an upper mold half into respective mold cavities. When the two half-moulds are separated, the parisons adhere to the respective cores and are then discharged into respective slots of a delivery box or into a small chamber of a blow-moulding device arranged between the two half-moulds. In the first case, before the start of a new injection-moulding cycle, the parisons are cooled by the circulating air flow as the delivery boxes are taken out in the lateral direction, the solidified parisons then falling from the respective slots into the pockets of the underlying conveyor belt, which conveys them to the blow-moulding station. In the second case, the core is hollow and its parison can fall down into blow-moulding cells whose mutually separate walls are closed by fluid or mechanical means. Where the parison is inflated by the air injected through the core, the formed bottle is removed from the cells after the blow-moulding device has been removed in the lateral direction, and a new injection-moulding cycle is started.

US4836767 to Schad et al describes an apparatus for producing plastic articles which is capable of simultaneously manufacturing and cooling plastic articles. The apparatus comprises a stationary mold half having at least one mold cavity, at least two cooperating mold sections, each mold comprising at least one core element mounted to a moving transfer plate that aligns a first of the cooperating mold sections with the stationary mold half and positions the other of the cooperating mold sections in a cooling position. A means for cooling the plastic article being manufactured in the cooling position and a means for moving the transfer plate along a first axis so that the aligned mold section engages the stationary mold half while the second mating mold section simultaneously contacts the plastic article thereon with the cooling means.

An apparatus for cooling and curing a preform is described in US5232715 to Fukai. The apparatus involves the step of introducing a preform, in a hot state, discharged from an injection molding machine, into a cooling tube. The cooling device includes a bottom opening and an upper opening. Through the cooling duct, cooling air can flow from the bottom opening to the upper opening. The bottom opening has a fan for cooling air. The flow of cooling air, which flows in rotation between a preform and a coolant supplied to a refrigerated core inserted into the preform, forcibly cools the preform from the inside and the outside.

Japanese patent JP7-171888, issued to hirowastari et al, relates to a forced cooling device for preforms. The apparatus comprises a cooling tool for supporting a plurality of preforms, a first air cooling device placed on the cooling tool for injecting cooling air to the inside of the preforms, and a second air cooling device placed below the cooling tool for injecting air to the outside of the preforms.

US5772951, assigned to the applicant and incorporated herein by reference, and assigned to Cokhead et al, relates to a preform storage and temperature conditioning apparatus for connecting one or more injection molding machines to a blow molding station. This enables the injection molding machine to be operated while the blow station is not operating. The preform storage device of the' 951 patent may contain a plurality of preform conveyors, each of which contains an injected preform. According to the' 951 patent, the preform from the mold is cooled to a sufficient degree to avoid certain problems such as, for example, crystallization, deformation, and surface damage. These preforms are stored and temperature-regulated so that they are ready for the blow-moulding step according to their temperature and quantity. The' 951 patent does not teach a multi-stage compact cooling station that houses relatively hot and freshly made preforms. The' 951 patent also fails to disclose a method and post-ejection cooling station for extending preform cooling time without affecting injection molding cycle time.

The mold release cooling becomes critical and difficult to achieve as the injection molding cycle time is reduced. This is particularly inevitable when the blow moulding to be formed is made of a resin such as, for example, PET. Since the in-mold cooling is shorter than usual, the solidification proceeds from the outside and inside of the ejected preform, but the temperature is still warm and the solidification is not complete in the walls. The internal heat reheats and reduces the strength of the inner and outer skin layers of the preform, and the preform is therefore susceptible to breaking and sticking together. Preforms formed with a fast cycle time and preforms cooled after being ejected by known methods and apparatus are now hot when they are cast onto a conveyor. These preforms may stick together or be damaged by impact to the belt or other preform during operation. This increases cycle time if the cooling time on the take-out plate or other known cooling device is extended, such as by trying to connect to an injection molding machine.

It is still very important to develop a method and apparatus for keeping the skin temperature as low as possible during the preform ejection, post-ejection cooling and transport after opening the mold.

After injection molding, the molded preforms are moved directly to a blow molding machine where they are blown into finished articles such as bottles or containers. The preform is reheated to blow-moulding temperature prior to the blow-moulding process. The blow-moulding process can be carried out immediately after the injection moulding, for example using a combined injection-blow moulding machine. In some cases, the preforms blown in this way are not completely cooled and therefore require less heat during the reheating process. In another method, the preforms are fully cooled after injection molding and then stored and transported to a different location for re-heating and final blow molding.

The reheat process described requires careful monitoring to ensure that all preforms have the same temperature prior to the blow molding step. It is not easy to implement these controls with a small simple device.

It is still important to provide a simple process and high productivity apparatus for cooling and reheating preforms prior to injection molding and blow molding.

Disclosure of Invention

It is therefore an object of the present invention to provide a method and apparatus for extending the cooling time of preforms without increasing cycle time and without increasing the size of the molding system.

It is a further object of the present invention to provide an apparatus as above that uses a modular and compact cooling device without increasing the injection molding cycle time.

It is a further object of the present invention to provide a method and apparatus as above which is suitable for cooling blow molded preforms made of one or more materials.

It is a further object of the present invention to provide a method and apparatus for temperature conditioning a shaped preform prior to the blow molding step.

According to the present invention, the temperature adjustment process may be a multi-stage cooling, a multi-stage cooling followed by reheating, or a multi-stage reheating process. In all cases, these processes are carried out in the same compact plant, in which the preforms are transferred from one station to the next.

The method and apparatus of the present invention achieve the above objects.

As previously mentioned, the present invention is directed to a multi-stage, post-mold cooling method and apparatus for use with an injection molding machine having significant cycle times and high throughput. The plant of the invention comprises a heat treatment device/station comprising means for separating batches of preforms, several mutually separated cooling stages for simultaneously cooling said batches of preforms and internal means for automatically transferring each batch of preforms from one stage to the next. In a preferred embodiment, the thermal management device/station is partially sealed to form a controlled temperature environment for processing the molded article.

The method for heat-treating molded articles according to the present invention generally comprises the steps of: molding a plurality of molded articles on an injection molding machine; removing said molded articles from said injection molding machine when said molded articles are hot and not sufficiently solidified; providing a thermal processing station having at least two internal thermal processing stages; conveying said molded articles to a first heat treatment stage of a heat treatment station; and heat treating the molded articles in the first cooling stage after the conveying step by subjecting the molded articles to at least one heat treatment to improve the quality of the molded articles without increasing the injection molding cycle time. In one embodiment of the invention, the method further comprises the steps of: receiving a first batch of molded articles into a first cooling stage of a thermal conditioning apparatus/station; cooling the first batch of molded articles; discharging the first batch of molded articles to a second cooling stage of the thermal conditioning apparatus/station; receiving a second batch of molded articles onto said first cooling stage; and simultaneously cooling the molded articles of the first and second batches. In another embodiment of the method of the present invention, a first batch of molded articles is free to fall to a first reheating stage in a thermal conditioning apparatus/station.

The present invention solves the cooling problem of the prior art by removing the hotter preform from the post-ejection delivery and cooling device which serves directly with the injection molding machine. The present invention uses a novel heat treatment apparatus/station that can receive any number (batches of 10 batches of preforms) of hotter preforms and cool them for as long as necessary, thus avoiding any quality problems.

Further details of the method and apparatus of the invention, together with further objects and advantages thereof, will be described with reference to the following description and the accompanying drawings. In the drawings, like reference numerals refer to like parts.

Drawings

FIG. 1 is a top plan view of an injection molding system including the inventive heat treatment apparatus of the present invention;

FIG. 2 is a side view of another injection molding system including a rotary table injection molding machine and the inventive heat treatment apparatus of the present invention;

FIGS. 3(A) -3(D) are schematic views of a preform passing through a heat treatment apparatus according to the present invention;

FIG. 4(A) is a cross-sectional view of a preform;

FIG. 4(B) is an exploded view of the wall of the preform of FIG. 4 (A);

FIG. 4(C) shows the temperature gradient along the wall thickness;

FIG. 5 is a cross-sectional view through a thermal management device according to the present invention;

FIGS. 6(A) -6(D) illustrate a heat treatment apparatus having a reheating station in accordance with the present invention; and

fig. 7 shows a cooling structure.

Detailed Description

Referring now to the drawings, FIG. 1 illustrates an injection molding system 10, the injection molding system 10 including an injection molding machine 12, the injection molding machine 12 having a mold formed of a core plate 14 and a cavity plate 16. The core plate 14 has a plurality of cores 20 and the cavity plate 16 has a plurality of cavities 24. Generally, the number of mold cores 20 is equal to the number of mold cavities 24.

The core plate 14 is axially movable along the draw cylinder 18 between an open mold position and a closed mold position in a known manner. When the core plate 14 is in the closed mold position, it cooperates with the cavity plate 16 to form a plurality of mold cavities (not shown). An injection device 26 provides molten material to each mold cavity using known operating systems (not shown) and/or sprues (not shown). When the mold is closed, a newly formed molded article 28, such as a preform for a blow molding system, is cooled somewhat by cooling channels (not shown) in mold core 20 and cavity plate 16.

A robot 30 is provided that includes a take-out plate 32. The take-out plate 32 has a plurality of holders 34 for receiving the molded articles 28 from the mold cores 20. In operation, the take-out plate 32 moves between the core plate 16 and the cavity plate 14 when the core plate 14 and the cavity plate 16 are in the unclamped position. After aligning the empty holder 34 with the mold core 20, the molded article 28 is removed from the mold 20 in a known manner, such as with a stripper plate (not shown), and placed on the holder 34. The take-out plate 32 is then retracted to a position adjacent the injection molding machine 12 to resume another injection molding cycle.

The take-out plate 32 is then rotated 90 degrees to align the molded articles 28 with the thermal management device 36 in accordance with the present invention.

The means for axially moving the take-out plate 32 and rotating the take-out plate 32 between a position outside the injection molding machine and a position between the two plates of the core plate 14 and the cavity plate 16 may comprise any suitable means known in the art.

Referring to FIG. 2, another injection molding system 10' is shown. The system 10 ' includes an injection molding machine 12 ', the injection molding machine 12 ' having a cavity plate 16 ' and a rotary table core plate assembly 40, the rotary table core plate assembly 40 being axially movable along a plurality of draw cylinders 18 ' between an open mold position (as shown in fig. 2) and a closed mold position. When in the closed mold position, the turret core plate arrangement 40 forms a plurality of mold cavities (not shown). An injection unit 26' provides molten material into the plurality of mold cavities to form a plurality of molded articles 28.

Turret core plate assembly 40 has a center block (not shown) mounted for rotation about an axis 46 by two trunnions on a pair of side plates 44. A plurality of core plates 42, for example 4 core plates, are mounted to the center block. Each core plate 42 has a plurality of cores 20' attached thereto or formed integrally therewith. The number of mold cores 20 'on each core plate 42 generally corresponds to the number of mold cavities on the cavity plate 26'. The side plates 44 each have a support with spacers 45 for allowing the turret core plate arrangement 40 to move along the draw cylinder 18'. Any suitable means known in the art may be used to rotate the center block and core plate 42 about axis 46. Similarly, any suitable means known in the art may be used to move the apparatus 40 between the open and closed mold positions.

The cavity plate 16' and the apparatus 40 each have means (not shown) for cooling the newly formed molded article or preform 28 while it is within the cavity. The cooling means may comprise any suitable cooling means known in the art.

After the first batch of articles 28 is formed, the apparatus 40 is moved to the unclamped position and rotated so that a new core plate 42 having the cores 20 is aligned with the cavity plate 26'. In this way, batches of molded articles can be formed quickly. As desired, each batch of molded articles 28 on the core 20' may be further cooled while the core plate assembly 40 is rotated. When the core plate 42 with the molded article 28 reaches the lowermost position, the article 28 is ejected from the core 20' and discharged into the thermal management device 36 of the present invention. Any suitable means known in the art (not shown) may be used to demold the article 28. For example, a stripper plate or stripper pin may be used.

As shown in fig. 4(a) -4(C), a typical preform 28 has a neck-forming portion 48 and a neck-finish or dome portion 50. Because the preform 28 is still hot when it is removed from the mold, the heat it contains may cause crystallization to occur at portions 48 and 50. Therefore, it is necessary to perform mold-release cooling to prevent crystallization from occurring. A typical wall structure of such a preform is shown in fig. 4 (B). As shown, the wall includes a hot inner skin layer 52, a hot outer skin layer 54, and a central portion 56. The temperature gradient across the wall is shown in fig. 4 (C).

Fig. 3(a) -3(D) and 5 illustrate one embodiment of a thermal processing station/apparatus 36 according to the present invention that may be used in the injection molding system shown in fig. 1 and 2. The heat treatment station/device 36 is used to extend the mold release cooling time without increasing the injection molding cycle time.

As shown in fig. 3(a) -3(D) and 5, the thermal processing station/apparatus 36 is modular in nature and has the form of a compact box. The footprint of the box is typically slightly larger than the dimensions of the molded preform array after demolding. And the height H of the box depends on the number of batches of molded articles or preforms that need to be cooled at the same time.

The heat treatment station/apparatus 36 includes a plurality of cooling stages 60, each cooling stage 60 simultaneously cooling a different batch of preforms 28. Each cooling stage 60 has a plurality of cooling tubes 62 within which the preforms are placed when they are cooled. As can be seen from the figure, the cooling tubes 62 on one cooling stage are aligned with the cooling tubes 62 of the adjacent cooling stage. The cooling tubes 62 are used to separate the preforms of a particular batch from each other to prevent them from sticking to each other.

The cooling stages 60 are separated by axially movable baffles 64. The baffle plate 64, as shown, includes a plurality of openings 66. Each opening 66 allows the preform 28 to fall freely onto the cooling tube 62 of the next cooling stage, and eventually off the device 36, at the outlet of the respective cooling tube 62 of the first cooling stage. Any suitable means known in the art may be used to move the flapper 64 between the aligned and non-aligned positions of the openings. For example, an air piston assembly 68 may be used to move each baffle plate 64 between a first position and a second position; in the first position, each opening 66 is aligned with the outlet of a respective cooling tube 62, and in the second position, a solid portion or block portion of the baffle closes off the outlet of each cooling tube 62. The baffle system provides the heat treatment station/apparatus 36 with internal means for automatically moving each batch of formed preforms from one cooling stage to the next.

The thermal conditioning station/apparatus 36 preferably includes a plurality of rows of aligned cooling tubes 62. The columns may be formed in any desired shape or form. A particular baffle 64 is typically associated with a particular row of cooling tubes 62. Thus, as shown in FIG. 5, all of the preforms 28 on a particular batch may be held simultaneously within the cooling tubes 62 of a particular stage 60, or dropped simultaneously from a row of cooling tubes. Fig. 3 shows the various steps performed during post-mold cooling and the respective positions of the preform 28 and baffle 64 during these steps.

Heat treatment station/apparatus 36 includes a telescoping tube 70 for receiving molded articles or preforms 28 from take-out plate 32 or turret core plate apparatus 40. Each telescoping tube 70 is aligned with a respective cooling tube 62 of the first cooling stage 60, and the telescoping tubes 70 are movable between a receiving or extended position and a retracted position. Any means known in the art may be used to move the telescoping tube between its various positions.

To effect cooling, each cooling tube 62 has small holes 72 for allowing cooling air to enter the cooling tube and flow around the preform 28. To achieve the flow of cooling air, the thermal conditioning station/unit 36 has a blowing unit 74, for example a fan, associated therewith. The blowing device 74 circulates air over the various cooling stages 60 to effect cooling of the preforms 28 by convection. As shown in fig. 5, the air stream created by the blowing device 74 enters the small holes in each cooling tube and then flows around the preform 28. The air-blowing device 74 may be contained within the thermal treatment station/device 36 or as an external device to the thermal treatment station/device 36. When the air-blowing unit 74 is provided as an external device to the thermal treatment station/unit 36, it blows air through an opening 80 in the wall of the unit 36. Although FIG. 5 shows a single air-blowing device 74, the cooling device 36 may have separate air-blowing devices for each cooling stage 60. This may allow different cooling stages to have different cooling rates.

During operation, the preform 28, which is at temperature T0 when removed from the take-off plate 32 or core plate 42, enters the cooling tube 62 on the first cooling stage 60 through the telescoping tube 70. In this initial stage, the baffle 64 is in a tube-closed position or an open non-aligned position. The preform 28 on the first cooling stage can then be cooled by convection to the desired temperature T₁. After the preform has reached the temperature T₁Thereafter, the baffle 64 is moved to a tube open position in which the openings 66 are aligned with the outlets of a particular row of cooling tubes 62. The preform 28 falls freely onto the second cooling stage 60 where the preform 28 is cooled by convection to a desired temperature T₂. After the first batch of preforms 28 has fallen onto the second cooling stage, a second batch of preforms may be introduced into the cooling tubes of the first cooling stage. In this way, multiple batches of preforms can be cooled simultaneously. Although fig. 5 shows the thermal conditioning station/device 36 having two cooling stages, the device 36 may have virtually any number of cooling stages. In this way, more than two batches of preforms can be cooled simultaneously.

After cooling is complete, the preforms 28 may be discharged from the lowermost cooling stage directly onto the conveyor 76 or onto a movable preform conveyor 78. The conveyor 78 may in principle be similar to the conveyor disclosed in US5772951, which is incorporated by reference in this application. The cooled preforms can be finally transferred to storage and handling towers, as required, see US 5772951.

Sometimes the cooled molded article or preform 28 must be reheated to prepare the preform for later operations such as the blow molding step. Fig. 6 shows a two-stage thermal conditioning stage 136 that may be used in applications where the cooling device 36 is used. The first section of the temperature conditioning station 136 is used to cool the preform 28 to prevent crystallization and deformation, and to heat the preform to the same temperature. The second section of the temperature conditioning station 136 is used to reheat the preform 28. The cooling section is similar to the cooling device 36 as shown in fig. 3(a) -3(D) and fig. 5. The cooling section also has a plurality of aligned cooling stages 60 for simultaneously cooling different batches of preforms 28. As shown in fig. 6(a) -6(D), the temperature adjustment stage 136 includes a plurality of aligned cooling tubes 62 located on different cooling stages 60. Telescoping tube 70 is connected to the uppermost end of cooling tube 62. As previously described, one baffle 64 along with each cooling stage retains the preform 28 within the cooling tube 62 and allows the preform to freely drop onto the next cooling stage. The operation of the baffle 64 is similar to that described previously. Similarly, the cooling at each cooling stage 60 is also the same as previously described.

Preferably, the wall 82 with the thermal insulation 84 is disposed within the temperature adjustment stage 136 to prevent heat from the reheating section 86 from interfering with the cooling operation.

As shown in fig. 6(a) -6(D), the reheat section 86 includes a plurality of tubes 88 for containing the cooled preforms. An axially movable baffle 64 retains the preform 28 within the heating tube 88. As previously described, the baffle 64 includes an opening 64 for allowing the heated preform to fall out of the heating tube 88. A heating device 90 is positioned adjacent to the heating tube 88 to heat the preform within the heating tube 88. Each heating device 90 may include any suitable heating means known in the art. According to one embodiment of the invention, a heating device 90 is positioned around the preform. By surrounding each preform with a heating device, it is no longer necessary to rotate each preform. Control means (not shown) are provided for modifying and establishing the temperature heated by each heating means respectively.

The heating device 90 may be composed of several heating elements that completely surround each preform, as desired. The heating elements may be tubes parallel to the longitudinal axis of the preform. Alternatively, the heating element may be in the form of an annular tube perpendicular to the longitudinal axis of the preform. Preferably, for preforms made of PET, the frequency spectrum of the heating device should lie in the IR range.

There are several advantages to including the heating station in the same "box" with multiple cooling stations. First, the injection molding and blow molding systems are relatively small in volume for the heating station and the cooling station to be placed one on top of the other. Secondly, the transfer from the cooling station to the heating station is the same as the transfer during cooling only, which makes the operation fast and simple. Third, there is no need to rotate the preform during heating.

Although only a single heating stage is shown in fig. 6(a) -6(D), the heat treatment station/apparatus 136 may have multiple heating stages to allow for gradual heating of the preform.

In another embodiment of the invention (not shown), the thermostat may be used only for the reheating process. In this case, the preform is partially or fully cooled after the forming step. The next step is to discharge the preforms onto a thermostat, where they are simply heated or reheated, using the same design as in fig. 6 (the heating section). The initial and final temperatures of the preforms entering or exiting the "tempering station", the number of sections heated and reheated inside the tempering "box" can vary from 2 to 3, 4 or more. The reheated preform is then immediately transferred to the blow-moulding station by known means.

Fig. 7(a) -7(C) illustrate a cooling structure 92 that may be used with the injection molding system of fig. 1 and 2. The cooling structure 92 has a plurality of cooling cores 94 for placing the formed preforms 28. Although convective cooling is the best mode, the cooling core 94 may effect cooling of the preform in any manner. The preform 28 may come directly from the mold cavity or from a take-off plate where the preform 28 is held within a cooling tube. The cooling structure 92 may be rotated about an axis 96 to cause the preforms 28 on the cores 94 to fall onto a row of guide tubes 98, which guide tubes 98 deliver the preforms to the apparatus 36 or multi-stage thermal processing apparatus 136. The cooling structure 92 may be rotated using any suitable means known in the art (not shown). As a preferred option, when the preforms are dropped, their neck-forming portion 48 faces downward. The preforms 28 are preferably held at each cooling stage 60 by a holder 100 in the form of a sleeve 102. These sleeves 102 may be opened or closed automatically. Retainer 100 replaces baffle 64. Any suitable means known in the art may be used to move the sleeve 102 between the open and closed positions. A variation of the apparatus of the present invention is to provide external cooling that may be supplemented by external cooling that may be provided through the guide tube 98 using the cooling core 94. The cooling structure 92 may have one or more surfaces with a cooling insert 94.

A baffle 164 may be provided between telescoping tube 70 and the first stage heat treatment station/apparatus 36, 136 to control the entry of preforms into the heat treatment station/apparatus 36, 136. As previously described, the baffle 164 may have an opening (not shown) to allow the preform to fall onto the first stage cooling stage. As previously described, the flapper 164 is axially movable between an opening-aligned position and an opening-misaligned position.

In a preferred construction, the apparatus 36 and the cooling station 136 are at least partially sealed to form a controlled temperature environment for conditioning the molded articles.

From the foregoing description, it will be seen that this invention provides a post-mold cooling method and apparatus which fully achieves the objects, aims and advantages set forth above.

Claims (49)

1. A method of heat treating a molded article outside a mold, comprising the steps of:

molding a plurality of molded articles on an injection molding machine;

removing said molded articles from said injection molding machine when said molded articles are hot and not sufficiently solidified;

providing a thermal processing station having at least two internal thermal processing stages; said thermal conditioning station comprising a plurality of tubes, each tube having a plurality of stages, and internal means for automatically transferring molded articles within said tubes from one stage to the next;

transferring said molded articles to a first thermal conditioning stage of said thermal conditioning station, said transferring step comprising placing a single said molded article into each of said tubes; and

the molded articles are thermally treated in the first thermal treatment stage of the thermal treatment station by subjecting the molded articles to at least one convective thermal treatment to improve the quality of the molded articles without increasing the injection molding cycle time.

2. The method of claim 1, wherein said heat treating step comprises convectively cooling an exterior surface of said molded article.

3. The method of claim 2, wherein said heat treating step further comprises heating said molded articles after said convection cooling step.

4. The method of claim 1, wherein said heat treating step comprises heating said molded articles in said heat treating station.

5. The method of claim 1, further comprising:

separating said molded articles from one another prior to transferring said molded articles to said first stage; and

the heat treating step includes simultaneously subjecting the molded articles in the first stage to a convective cooling treatment.

6. The method of claim 1, further comprising:

said molding step comprises molding a first batch of molded articles;

separating the molded articles in said first batch; and

said heat treating step comprises simultaneously subjecting said first batch of molded articles to a first convective cooling treatment in a first stage within said heat treatment station.

7. The method of claim 6, further comprising:

forming a second batch of molded articles;

separating said second batch of molded articles; and

said heat treating step comprises simultaneously subjecting said molded articles of said second batch to a first convective cooling treatment in said first stage and said molded articles of said first batch to a second convective cooling treatment in said second stage within said heat treating station.

8. The method of claim 7, further comprising:

forming a third batch of molded articles;

separating said molded articles of said third batch; and

said heat treating step comprises simultaneously subjecting said molded articles of said third batch to said first convective cooling treatment at said first stage, said molded articles of said second batch to said second convective cooling treatment at said second stage, and said molded articles of said first batch to a heating treatment at said third stage within said heat treating station.

9. The method of claim 1, wherein:

said step of removing molded articles comprises providing a take-out plate for removing said molded articles from said injection molding machine and positioning said take-out plate between the core and cavity positions of said injection molding machine to receive said molded articles; and

the step of transporting molded articles includes moving the take-out plate to a position adjacent the injection molding machine and rotating the take-out plate so that the take-out plate is aligned with an entrance of the thermal conditioning station.

10. The method of claim 1, wherein:

the injection molding machine includes a turret core plate assembly including a plurality of core plates;

said molding step including moving a first one of said core plates to a mold closed position to form a mold cavity portion;

said removing step comprising moving said first core plate relative to said cavity portion to remove said plurality of molded articles; and

said conveying step comprises rotating said turret core plate means until said first core plate is aligned with an entrance of said thermal conditioning station and stripping said molded articles from said first core plate.

11. The method of claim 1, further comprising cooling said molded articles prior to delivering said molded articles to said thermal conditioning station.

12. The method of claim 11, wherein:

said cooling step comprising placing said molded article on a cooling structure having a plurality of cooling cores and cooling said molded article on said cooling cores; and

said conveying step includes moving said cooling structure to a position aligned with said thermal conditioning station and removing said cooled molded articles from said cooling structure.

13. The method of claim 1, further comprising:

said heat treating step comprises subjecting each of said molded articles to a cooling air stream for a first period of time while each of said molded articles is in said first stage within said tube.

14. The method of claim 13, further comprising:

actuating said internal means to allow each of said molded articles to freely fall onto said second level within each of said tubes; and

said heat treating step further comprises subjecting said molded articles to a cooling air stream for a second period of time while each of said molded articles is in said second stage within said tube.

15. The method of claim 14, wherein the second period of time is different from the first period of time.

16. The method of claim 14, further comprising:

actuating said internal means to allow each of said molded articles within said tube to freely fall onto a third level; and

said heat treating step further comprises heat treating each of said molded articles while they are in said third stage.

17. The method of claim 16, further comprising: removing said molded articles from said heat treatment station after said heat treating step is complete and transferring said molded articles to a target location.

18. A thermal conditioning station for thermally conditioning molded articles, comprising;

holding means for holding separate batches of molded articles;

said holding means comprising a plurality of cylindrical tubes each comprised of a plurality of aligned tubular members;

internal means for holding each batch of said molded articles at a different level within said thermal conditioning station; and

means for simultaneously heat treating said batches of molded articles.

19. The thermal conditioning station of claim 18, further comprising:

each of said tubular members having an inlet and an outlet;

each of said internal retaining means comprises a baffle positioned between adjacent ones of said aligned tubular members;

said baffle having at least one opening therein for mating with the outlet of said at least one pipe element; and

moving means for moving said shutter between a first position and a second position; in said first position, said flap closes off the outlet of said at least one tubular member to retain said molded article within said at least one tubular member at a first stage; in said second position, said at least one opening is aligned with said outlet of said at least one tube member, thereby allowing said molded articles within said at least one tube member to freely fall onto a second level of said thermal conditioning station.

20. The thermal conditioning station of claim 19, wherein said thermal conditioning station is modular in nature, and said columnar tubes are arranged in a plurality of rows.

21. The thermal conditioning station of claim 19, further comprising means for convectively cooling said molded articles while said molded articles are at different levels within said thermal conditioning station.

22. The thermal conditioning station of claim 21, wherein each of said tubes has at least one opening in a sidewall thereof through which cooling air can flow; wherein the heat treatment station has means for passing a flow of cooling air into the selected tubular.

23. The thermal conditioning station of claim 22, further comprising:

a housing surrounding said tubular member, said housing having an opening in a sidewall; and

the means for causing cooling air to flow comprises fan means positioned outside the housing for causing air flow through openings in the side walls of the housing.

24. The thermal conditioning station of claim 19, further comprising:

the tubes are at least arranged in a line;

each of said tubes being formed of three spaced apart and aligned tubular members; and

at least two baffles associated with each tube in the at least one row of tubes; wherein said first baffle is positioned between said first and second tubular members of said tubular member of each tube of said at least one row of tubes; said second baffle being positioned between said second tubular member and said third tubular member of each tube of said at least one row of tubes.

25. The thermal conditioning station of claim 24, further comprising means for actuating each of said shutters to automatically transfer each of said molded articles from one stage to the next.

26. The thermal conditioning station of claim 24, further comprising a third baffle positioned adjacent each of said third tube outlets.

27. The thermal conditioning station of claim 24, further comprising means for heating a molded article located within said third tubular member.

28. The thermal conditioning station of claim 27, further comprising a wall having thermal insulation between said heating stage and an adjacent cooling stage.

29. The thermal conditioning station of claim 19, further comprising an extendable and retractable tube member movable relative to each of said tube members for collecting molded articles to be thermally conditioned.

30. The thermal conditioning station of claim 18, wherein said internal retaining means comprises a retainer at each stage at which said molded articles are thermally conditioned.

31. The thermal conditioning station of claim 30, wherein each said retainer comprises an axially movable sleeve for gripping a portion of said molded article.

32. The thermal conditioning station of claim 18, further comprising a set of guide tubes for guiding molded articles to said thermal conditioning station.

33. The thermal conditioning station of claim 32, further comprising:

the guide tube group is provided with a plurality of outlets; and

a shutter positioned between the outlet of each of said guide tube sets and the inlet of said thermal treatment station, said shutter being movable between a first position and a second position; in said first position, said shutter closes the passage of said molded articles into said thermal conditioning station, and in said second position, said shutter permits said molded articles to enter said thermal conditioning station.

34. An apparatus for heat treating molded articles outside of an injection molding machine, comprising:

means for removing said molded articles from said injection molding machine when said molded articles are hot and not sufficiently solidified;

a heat treatment station located external to said injection molding machine, said heat treatment station comprising at least two internal heat treatment stages;

conveying means for conveying said molded articles to said thermal conditioning station; and

said heat treatment station having a heat treatment means for subjecting said molded articles to at least one of said heat treatments in a first internal heat treatment stage to improve the quality of the molded articles without increasing the injection molding cycle time of the injection molding machine;

the thermal conditioning station comprises a plurality of tubes for receiving the molded articles and an internal retaining device associated with each tube for retaining the molded articles therein on a first stage of the thermal conditioning stage and then on a second stage of the thermal conditioning stage.

35. The apparatus of claim 34, wherein said thermal conditioning means comprises cooling means for convectively cooling exterior surfaces of said molded articles in said first thermal conditioning stage.

36. The apparatus of claim 35, wherein said thermal conditioning means further comprises heating means for heating said molded articles after cooling.

37. The apparatus according to claim 34, wherein said thermal conditioning means includes heating means for heating said molded articles while said molded articles are resident within said thermal conditioning station.

38. The apparatus of claim 34, wherein said take-off and transport means includes a take-off plate for receiving said molded articles from said injection molding machine while said molded articles are still hot.

39. The apparatus of claim 38, wherein said transfer device further comprises a rotatable frame having a plurality of cooling cores on a plurality of surfaces thereof, said cooling cores cooperating with said take-out plate to receive said molded articles, said rotatable frame being rotatable to allow cooled molded articles to be discharged into said thermal conditioning station.

40. The apparatus of claim 34, wherein said plurality of tubes are adapted to separate molded articles from one another within a batch when said molded articles are subjected to said at least one thermal treatment.

41. The apparatus of claim 40 wherein said delivery device further comprises a set of guide tubes having outlets aligned with the inlets of said tubes.

42. The apparatus of claim 34, wherein:

said injection molding machine having a turret core plate assembly having a plurality of core surfaces, said core surfaces engaging a cavity portion of said injection molding machine;

said removing means comprising means for removing one of said core surfaces from said cavity portion; and

said transfer means comprises means for rotating said turret core plate means until molded articles removed from said injection molding machine are aligned with said thermal conditioning station and means for removing said molded articles.

43. The apparatus of claim 34, further comprising a drive means for driving said internal holding means, said drive means automatically moving said molded articles in each tube from said first thermal conditioning stage to said second thermal conditioning stage.

44. The apparatus of claim 34, further comprising:

each of said tubes being substantially cylindrical and formed of a plurality of mutually aligned tubular members; and

said internal retaining means is comprised of at least one baffle positioned between adjacent tubular members; each of said baffles having an opening alignable with the outlet of a first of said tubular members and the inlet of a second of said tubular members; said flapper being movable between a first position and a second position; in said first position, a solid portion of each of said baffles retains said molded articles in said first thermal treatment stage by closing the outlet of a first of said tubular members; in the second position, the opening is aligned with the outlet of the first of the tube members, thereby allowing the molded articles to be freely transferred to the second thermal treatment stage.

45. The apparatus of claim 44, wherein:

each of said tubes having three aligned tube members; and

said internal holding means comprises two baffles, a first of said baffles being positioned between a first and a second of said three tubular members, a second of said baffles being positioned between a second and a third of said three tubular members, said baffles being actuated to permit heat treatment of molded articles within said tubes at three different heat treatment levels within said heat treatment station.

46. The apparatus of claim 34, wherein said thermal conditioning station has means for cooling a first batch of molded articles at a first of said thermal conditioning stages and means for simultaneously cooling a second batch of molded articles at a second of said thermal conditioning stages.

47. The apparatus according to claim 46, wherein said thermal conditioning station has means for heating a third batch of molded articles while said first and second batches of molded articles are cooling.

48. Apparatus according to claim 46, wherein said cooling means comprises a plurality of tubes and means for creating a flow of cooling air; said molded articles being located in the tubes; each of said tubes having at least one aperture for allowing cooling air to flow around at least one molded article in each of said tubes.

49. Apparatus according to claim 48, wherein said thermal conditioning station comprises a housing and said cooling air flow forming means is located outside said housing.