Abstract:
Disclosed, amongst other things, is a method of post-mold cooling of a molded article, the molded article having just been molded within mold halves, the method comprising: receiving, in a post-mold device, the molded article; subjecting the molded article to post-mold cooling, the post-mold cooling including: implementing a first post-mold cooling process portion in the post-mold cooling device at a first temperature; and implementing a second post-mold cooling process in the post-mold cooling device portion at a second temperature, said second post-mold cooling temperature being greater than said first post-mold cooling temperature; determining a switch point; triggering at the switch point, a transition from the first post-mold cooling process portion to the second post-mold cooling process portion.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present patent application is a Continuation of U.S. patent application Ser. No. 12/301,731 filed 20 Nov. 2008, which is a Continuation in Part and also claims the benefit and priority date of prior U.S. patent application Ser. No. 11/450,990, filed 12 Jun. 2006, now U.S. Pat. No. 7,421,310, issued 2 Sep. 2008. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention generally relates to, but is not limited to a method, molding machine, and computer-readable product for post-mold cooling a molded article, comprising balancing cooling rates between portions of the molded article to substantially reduce post-mold cooling related defects of the molded article, amongst other things. 
       BACKGROUND 
       [0003]    Some injection molded articles, for example plastic preforms of the variety that are for blow molding into beverage bottles, require extended cooling periods to solidify into substantially defect-free molded articles. To the extent that the cooling of the molded article can be effected outside of the injection mold by one or more post-mold devices then the productivity of the injection mold may be increased (i.e. lower cycle time). A variety of such post-mold devices, and related methods, are known and have proven effective at the optimization of the injection molding machine cycle time. 
         [0004]    In a typical injection molding system, such as the system  10  depicted with reference to  FIG. 1 , and as generally described in commonly assigned U.S. Pat. No. 6,171,541 (Inventor: NETER, Witold, et al.; Published: 9 Jan. 2001), just-molded, and hence partially cooled, molded articles  2  are ejected from the mold half  8 , when the mold halves  8 ,  9  are spaced apart, and into holders  50  (i.e. commonly known as a cooling holder, a take-off holder, or a cooling pipe, amongst others). The holders  50  are arranged on a post-mold device  15  (i.e. commonly known as an end-of-arm-tool, carrier plate assembly, removal device, post-cooling apparatus, amongst others), the post-mold device  15  configured to cyclically position the holders  50 , arranged on a supporting plate  16 , between an in-mold position between the mold halves  8 ,  9 , to receive the molded articles  2 , and an out-board position, as depicted, to allow the mold halves  8 ,  9  to close and begin another molding cycle. The construction and operation of the post-mold device  15 , including those having multiple-positions, is generally described in commonly assigned U.S. Pat. RE33,237 (Inventor: DEFLER, Frank; Published: 19 Jun., 1990). Preferably, the molded articles  2  are held in the holders  50  until the molded articles  2  have cooled sufficiently that they may be ejected without risk of further deformation. The injection molding machine includes a controller  30 , such as that described in commonly assigned U.S. Pat. No. 6,275,741 (Inventor: CHOI, Christopher; Published: 14 Aug. 2001), for controlling machine-control functions. 
         [0005]    The cooling of the molded articles  2  may be assisted by the use of pins  14  for expelling a cooling fluid onto an inner portion of the molded articles  2 , as shown with further reference to  FIG. 2B . The pins  14  are arranged on another post-mold device  12  (i.e. commonly known as a COOLJET, a trademark of Husky Injection Molding Systems Ltd.), the post-mold device  12  arranged to be cyclically positioned between a cooling position, with the pins  14  positioned adjacent the portion of the molded articles  2 , and an out-board position, as depicted. It is also known to use the molded article post-mold device  12  to extract the molded articles  2  from the holders  50  for a re-handling thereof, for instance, to a conveyor. 
         [0006]    A portion of the post-mold device  15  depicting a holder  50  arranged on the supporting plate  16  is shown with reference to  FIGS. 2A and 2B . The holder  50  is configured in accordance with the general teachings of commonly assigned U.S. Pat. No. 4,729,732 (Inventor: SCHAD, et al.; Published: 4 Mar. 1988). In particular, the holder  50  includes a tapered surface  52  defining a cavity for receiving a portion of the molded article  2 , the surface  52  being smaller than the heated molded article. The holder includes a cooling structure operative to shrink the molded article, upon cooling, with the molded article sliding inside the cavity to fit snugly therein. The holder  50  further includes a suction structure adjacent a closed end of the cavity for maintaining the molded article in the holder  50 . 
         [0007]    As shown with reference to  FIG. 2B , the cooling of the molded articles  2  may be assisted by the use of a coolant dispersion device  19  of a post-mold device  13  for dispersion of a coolant, such as cool air, around an exposed outer portion of the molded article; as generally described in commonly assigned U.S. Pat. No. 6,802,705 (Inventor: BRAND, Tiemo, et al.; Published: 12 Oct. 2004). 
         [0008]      FIG. 2A  depicts an initial position of the molded article  2  in the holder  50  immediately after having been received from the mold. 
         [0009]      FIG. 2B  depicts a completely seated position of the molded article  2  in the holder  50  after cooling, and related shrinkage, of the molded article  2 . 
         [0010]    The holder  50  comprises a holder  60  and an insert  70 . The insert  70  is arranged in the holder  60  to provide the closed end of the cavity. The suction structure comprises a pressure channel  54  that extends through the insert  70 , the channel  54  is connectable to an air pressure source  18 , provided in a plate  16  of the post-mold device  15 , via a pressure channel  18 ′ configured in the holder  60 . Likewise, the cooling structure comprises a coolant channel  62  configured around the holder  60 , and enclosed by a holder sleeve  64 , the coolant channel  62  connectable to a coolant source  17 , provided in the plate  16 , via a coolant channel  17 ′ in the plate  16 . The holder  60  and the insert  70  are held on the plate  16  by a fastener  72 . 
         [0011]    The coolant source  17  in the plate  16  is typically directly connected to a plant-wide coolant source. Typical plant-wide coolant sources include a chiller or a cooling tower to remove the heat added to the coolant from the molded article in the holder. Presently, faced with the problem of improving the efficiency of a molding cycle the common general knowledge in the molding art is to remove heat from the molded article holder as quickly as possible. The coolant, typically water, is preferably cooled to a temperature in the range of 6-10° C. In some high humidity molding environments the coolant may be kept warmer to avoid unwanted water condensation on the holder  50 . 
         [0012]    As can be seen with reference to  FIGS. 2A and 2B , a first portion of the molded article  2 ′ that is received in the cooled holder  50  will be cooled, by the holder  50 , at a first rate while a second portion of the molded article  2 ″ that is outside of the holder  50  will be cooled at a second rate. Under certain circumstances the second portion of the molded article  2 ″ can take longer to cool than the first portion of the molded article  2 ′. The relative cooling between the first and second portions of the molded article  2 ′,  2 ″ may be affected by one or more variables such as the distribution of plastic in the molded article  2 , the thermal profile of the molded article when ejected from the mold  8 ,  9 , the relative first and second rates of cooling, amongst others. Whenever the time required for post-mold cooling the second portion of the molded article  2 ″ is the limiting factor there is the risk that the first portion of the molded article  2 ′ may become over-cooled. An over-cooled first portion of the molded article  2 ′ is prone to deform. 
         [0013]    Problems associated with cooling molded articles in the holder  50  may include localized sink marks and ovality. 
         [0014]    With the relatively long molding cycle-times of the past it was generally possible to adjust the geometry of the cavity in the holder  50  to address the known defects. For instance, ovality defects may be addressed by adjusting the cavity in the holder  50  to be slightly smaller. 
         [0015]    With increasingly aggressive molding cycle-time it is not always possible to address the defects by simple adjustment of the cavity geometry in the holder as adjusting the geometry for one defect may have the effect of making the another defect more prominent. 
       SUMMARY 
       [0016]    According to a first broad aspect of the present invention, there is provided a method of post-mold cooling of a molded article, the molded article having just been molded within mold halves, the method comprising: receiving, in a post-mold device, the molded article; subjecting the molded article to post-mold cooling, the post-mold cooling including: implementing a first post-mold cooling process portion in the post-mold cooling device at a first temperature; and implementing a second post-mold cooling process in the post-mold cooling device portion at a second temperature, said second post-mold cooling temperature being greater than said first post-mold cooling temperature; determining a switch point; triggering at the switch point, a transition from the first post-mold cooling process portion to the second post-mold cooling process portion. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0017]    A better understanding of the exemplary embodiments of the present invention (including alternatives and/or variations thereof) may be obtained with reference to the detailed description of the exemplary embodiments along with the following drawings, in which: 
           [0018]      FIG. 1  is a top elevation view of a known injection molding system; 
           [0019]      FIG. 2A  is a section view through a post-mold device depicted in the injection molding system of  FIG. 1  at a time before the molded article has completely seated therein; 
           [0020]      FIG. 2B  is a section view through a post-mold device depicted in the injection molding system of  FIG. 1  at a time after the molded article has completely seated therein; 
           [0021]      FIG. 3  is a top elevation view of an injection molding system in accordance with a non-limiting embodiment of the present invention; 
           [0022]      FIG. 4  is a top elevation view of an injection molding system in accordance with another non-limiting embodiment of the present invention. 
       
    
    
       [0023]    The drawings are not necessarily to scale and are may be illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details that are not necessary for an understanding of the exemplary embodiments or that render other details difficult to perceive may have been omitted. 
       DETAILED DESCRIPTION OF EMBODIMENTS 
       [0024]      FIG. 3  is an injection molding system  110  in accordance with a non-limiting embodiment of the present invention. The molding system  110  is similar to the known molding system  10  described hereinbefore which included the post-mold devices  12 ,  15 . The molding system  110  further includes a temperature control device  20  for controlling the temperature of the holder  50 , on post-mold device  15 , to avoid imparting cooling related defects to the molded article  2 . 
         [0025]    The method in accordance with an embodiment of the present invention includes balancing cooling rates between the portions  2 ′,  2 ″,  2 ′″ of the molded article  2 , as shown with reference to  FIG. 2B , to substantially reduce post-mold cooling related defects of the molded article. 
         [0026]    The balancing of the cooling rates between portions  2 ′,  2 ″,  2 ′″ is preferably controlled such that each of the portions of the molded article  2 ′,  2 ″,  2 ′″ arrive at respective ejection temperatures, that substantially precludes post-ejection defects, at the substantially the same time. 
         [0027]    The method preferably includes controlling the cooling rate imposed on one or more of the portions of the molded article  2 ′,  2 ″,  2 ′″ by one or more post-mold devices  12 ,  13 ,  15  to effect the balancing of the cooling rates between the portions  2 ′,  2 ″,  2 ′″. 
         [0028]    In accordance with an embodiment of the present invention the method includes arranging a first portion of the molded article  2 ′ in a holder  50  of a post-mold device  15  and controlling the temperature of the holder  50  to avoid imparting cooling related defects to the molded article ( 2 ). 
         [0029]    Preferably, the controlling of the temperature of the holder  50  minimizes a temperature differential in the molded article  2  at a transition between the first portion of the molded article  2 ′ arranged in the holder  50  and a second portion of the molded article  2 ″ that is outside of the holder  50 . 
         [0030]    Preferably, controlling the temperature of the holder  50  includes controlling the temperature of a coolant media that is circulated for controlling the temperature of the holder  50 . The temperature control of the coolant media may be performed by circulating the coolant media through the temperature control device  20 . 
         [0031]    Alternatively, the controlling the temperature of the holder  50  includes the controlling the flow rate of a coolant that is circulated to control the temperature of the holder  50 . 
         [0032]    Preferably, controlling the temperature of the holder  50  includes selecting a temperature of the holder  50  whereby the first and second portions of the molded article  2 ′,  2 ′″ are controllably cooled at first and second cooling rates such that the molded article portions  2 ′,  2 ′″ arrive at ejection safe temperatures at substantially the same time. 
         [0033]    A technical effect of the embodiment of the present invention is a reduction in the formation of defects in the molded article  2  that are related to post-mold cooling of the molded article. 
         [0034]    In accordance with the embodiment of the present invention, the technical effect was prominent when the temperature of the coolant media for cooling of the holder  50  was heated above ambient temperature and below a glass temperature of a resin used to form the molded article  2 . More preferably, the temperature of the holder  50  is selected to be between about 35° C. and 65° C. More preferably still the temperature of the holder  50  is selected to be about 50° C. 
         [0035]    Preferably, the temperature of the holder  50  is homogenous. Alternatively, a subtle gradient along the molded article may be useful to reduce local defects, such as sink marks, while still avoiding ovality defects. 
         [0036]    Preferably, the molding machine controller  30  controls the temperature control device  20  for controlling the temperature of the coolant media using closed-loop control. Alternatively, the temperature control may be open-loop control. Alternatively, the temperature control device  20  may include a dedicated controller, not shown, the dedicated controller may be operatively linked or entirely independent from the machine controller  30 . Accordingly, the method of controlling the temperature of the coolant media may further include the sending coolant temperature set-points from a molding machine controller  30  to the dedicated controller in the temperature control device  20 . In addition, operational feedback from the temperature control device  20  may be shared with the molding machine controller  30 . 
         [0037]    In accordance with an alternative embodiment of the invention, the cooling rate of one or both or the molded article portions ( 2 ″,  2 ′″) may be effected similarly by controlling the post-mold devices  13 ,  15 . For example, the coolant flow rate, or coolant temperature may be controlled through the pin  14  and/or dispersion device  19  of post-mold devices  12 ,  13 . 
         [0038]    Any type of controller or processor may be used to balance the cooling rates between portions ( 2 ′,  2 ″,  2 ′″) of the molded article ( 2 ), as described above. For example, one or more general-purpose computers, Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), gate arrays, analog circuits, dedicated digital and/or analog processors, hard-wired circuits, etc., may receive input from the feedback signals described herein. Instructions for controlling the one or more of such controllers or processors may be stored in any desirable computer-readable medium and/or data structure, such floppy diskettes, hard drives, CD-ROMs, RAMs, EEPROMs, magnetic media, optical media, magneto-optical media, etc. An expert system may be implemented in the controller  30  to automatically control the post-mold devices  12 ,  13 ,  15  to adjust the cooling rates of the portions ( 2 ′,  2 ″,  2 ′″) based upon quantitative and/or qualitative feedback on the state of the molded article  2 . 
         [0039]    With reference to  FIG. 4 , another non-limiting embodiment of a molding system  110 ′ will now be described in greater detail. The molding system  110 ′ can be substantially similar to the above-described molding system  110 , but for the specific differences to be discussed herein below and, as such, like elements are denoted with like numerals. Within these non-limiting embodiments of the present invention, the molding system  110 ′ comprises a sensor  402  associated with the post-mold device  15 . 
         [0040]    Generally speaking, the purpose of the sensor  402  is to determine temperature associated with operation of the holders  50 . It should be expressly understood that in some embodiments of the present invention, the sensor  402  is configured to measure the temperature, however in other embodiments, the sensor  402  can measure another parameter which can then be used to determine a temperature value. Examples of such a proxy value of an operational parameter that can be used include, but are not limited to, pressure exerted by a preform  2  against a wall of the holder  50  and the like. In some embodiments of the present invention, the sensor  402  can be implemented as a thermocouple. In other embodiments of the present invention, the sensor  402  can be implemented as a thermistor. In yet other embodiments of the present invention, the sensor  402  can be implemented as a thermal emission camera (ex. an infrared camera and the like). In yet further non-limiting embodiments, the sensor  402  can be implemented as a pressure measurement device (ex. a pressure transducer and the like). Other alternative implementations are, of course, possible. 
         [0041]    In some embodiments of the present invention, the sensor  402  can comprise a single sensor  402  associated with the post-mold device  15 . In other embodiments of the present invention, the sensor  402  can comprise a plurality of sensors  402 ; each of the plurality of sensors  402  being associated with a respective holder  50 . In alternative non-limiting embodiments of the present invention, which are particularly applicable in those implementations where the post mold devices  12 ,  15  are configured to implement a so-called multi-position post-mold cooling function, the sensor  402  can comprise a plurality of sensors  402 ; each of the plurality of sensors  402  being associated with a selected one of the holders  50  in a given position of the post-mold cooling cycle. In other words, the sensor  402  can comprise a plurality of sensors  402 ; each of the plurality of sensors associated with a given position of the post-mold cooling function. For example, in a molding system  110 ′ which implements a three-position post-mold cooling function, three instances of the sensors  402  can be used. 
         [0042]    The sensor  402  is configured to generate a signal  403  representative of an operational parameter (such as the temperature or the like), associated with operation of the holders  50 . 
         [0043]    The sensor  402  is coupled to the controller  30  via a communication link  404 . In some embodiments of the present invention, the communication link  404  can be implemented as a wired link. As will be appreciated by those of skill in the art, within these embodiments of the present invention, the wired link is configured to withstand operating temperatures associated with the molding system  110 ′. In other non-limiting embodiments of the present invention, the communication link  404  can be implemented as a wireless link. Those skilled in the art will appreciate that a plethora of possible wireless communication protocols can be used. Examples of wireless communication protocols that can be used include, but are not limited to, Wi-Fi, BlueTooth, Wi-Max and the like. The sensor  402  is operable to transmit the signal  403  to the controller  30  via the communication link  404 . Naturally, in alternative non-limiting embodiments of the present invention, the sensor  402  can be coupled to a dedicated controller (not depicted) separate from the controller  30 . 
         [0044]    How the sensor  402  generates and transmits the signal  403  is not particularly limited. For example, the sensor  402  can sense an operating parameter, generate the signal  403  representative of the sensed operating parameter and to transmit the signal  403  to the controller  30  at regular time intervals. In other non-limiting embodiments of the present invention, the sensor  402  can sense an operating parameter, generate the signal  403  representative of the sensed operating parameter and to transmit the signal  403  to the controller  30  at a beginning of a given position of the post-mold cooling cycle. For example, within a four-position post-mold cooling cycle, the sensor  402  can repeat this routine at a beginning of each of the four-positions of the post-mold cooling cycle. 
         [0045]    Alternatively, the sensor  402  can perform a similar routine at a beginning of a first position of a multi-position post-mold cooling cycle. In yet further non-limiting embodiments, the sensor  402  can perform the same routine upon receipt of a request signal (not depicted) from the controller  30 . 
         [0046]    Given the architecture of  FIG. 4 , it is possible to implement a method for post-mold cooling according to another non-limiting embodiment of the present invention. 
         [0047]    At a first instance in time, i.e. at a beginning of a post-mold cooling cycle, a molded article  2  is received within the holder  50  and a first portion of the post-mold cooling cycle begins. Within the first portion of the post-mold cooling cycle, the temperature control device  20  controls the coolant media that is circulated for controlling the temperature of the holder  50  to a first cooling temperature. As a non-limiting example and not as a limitation, the first cooling temperature can be 10° C. 
         [0048]    At a second instance in time, i.e. at some point in time after the first instance in time, a second portion of the post-mold cooling cycle commences. Within the second portion of the post-mold cooling cycle, the temperature control device  20  controls the temperature of the coolant media that is circulated for controlling the temperature of the holder  50  to a second cooling temperature, which is greater then the first cooling temperature. As a non-limiting example and not as a limitation, the second cooling temperature can be 65° C. 
         [0049]    A point in time when the first post-mold cooling portion ends and the second post-mold cooling portion commences, can be broadly called a switch point. How the switch point is determined is not particularly limited and can be implemented in several possible alternatives. 
         [0050]    Pre-Determined Point in Time
       In some embodiments of the present invention, the switch point can be implemented as a pre-determined point in time. For example, an operator operating the molding system  110 ′ can set-up the switch point using, for example, a human-machine interface (not depicted) of the molding system  110 ′. This switch point can be expressed as a value representative of time elapsed since a beginning of a post-mold cooling cycle (ex. 2 seconds, 3 seconds, 4 seconds, 5 seconds or any other suitable value). Alternatively, this switch point can be expressed as a value representative of number of positions of the post-mold cooling cycle expired after a beginning of the post-mold cooling cycle (ex. a switch point after 1 position is completed, 2 positions are completed, 3 positions are completed, 4 positions are completed, 2.5 positions are completed, 3.2 positions are completed and the like). Alternatively, a combination of the number of positions and elapsed time since the beginning of the last position can be used (ex. 2 positions and 1 second, etc.).   Within these embodiments of the present invention, the switch point can be adjusted from time to time. For example, the operator can change the switch point using, for example, the human-machine interface (not depicted) to move the switch point closer or further way from the beginning of the post mold cooling cycle.       
 
         [0053]    Temperature Value
       In alternative non-limiting embodiments of the present invention, the switch point can be implemented as a temperature value associated with operation of the holders  50  (i.e. a target temperature). For example, the switch point can be expressed as a temperature value associated with molded articles  2  being treated in a given position of the post-mold cooling cycle or a holder  50 . As an example and not as a limitation, the switch point can be expressed as 65° C. In other words, when the molded article  2  reaches the temperature of 65° C., a switch between the first post-mold cooling portion and the second post-mold cooling portion occurs.   Within these embodiments of the present invention, the controller  30  monitors the signal(s)  403  received from the sensor  402  or the plurality of sensors  402 . When a given signal  403  is indicative of a given molded article  2  reaching the target temperature, a determination is made that the switch point has been reached.   In those embodiments of the present invention, where the sensor  402  is implemented as a plurality of sensors  402 ; each of the plurality of sensors being associated with a given holder  50 ; the controller  30  receives a plurality of signals  403  from each of the plurality of sensors  402 . The controller  30  then individually analyzes each of the plurality of signals  403 .   In those embodiments of the present invention, where the sensor  402  is implemented as a plurality of sensors  402 ; each of the plurality of sensors being associated with a given position of the post-mold cooling function; the controller  30  receives a plurality of signals  403  from each of the plurality of sensors  402 . The controller  30  then individually analyzes each of the plurality of signals  403  for a given position of the post-mold cooling cycle. Within these embodiments of the present invention, an assumption is made that molded articles  2  being treated within the same position of the post-mold cooling cycle have substantially the same temperature.   In those embodiments of the present invention, where the sensor  402  is implemented as a single sensor, the controller  30  receives a single signal  403  from the single sensors  402 . The controller  30  then analyzes the single signal  403  and performs a calculation routine to determine a respective temperature associated with each position of the multi-position post-mold cooling cycle.       
 
         [0059]    The temperature control of the coolant media may be performed by circulating the coolant media through the temperature control device  20 . How the temperature control device  20  controls the coolant media is not particularly limited. In some embodiments of the present invention, the temperature control device  20  can control the coolant media by heating and/or cooling the coolant media. In alternative non-limiting embodiments, the temperature control device  20  can control the coolant media by controlling a rate of flow of the coolant media. In yet further non-limiting embodiments of the present invention, the temperature control device  20  can control the coolant media by shutting off supply of the coolant media at the second post-mold cooling portion. Other alternatives are, of course, also possible. Yet in further non-limiting embodiments of the present invention, the temperature control device  20  can control the coolant media by changing the coolant media from a first type of coolant media to a second type of coolant media. Other alternatives are, of course, also possible. 
         [0060]    Accordingly, it should now become apparent that the method of controlling post-mold cooling broadly includes steps of balancing cooling rates during a post-mold cooling function. More specifically, the balancing of cooling rates may include balancing of cooling rates among various portions  2 ′,  2 ″,  2 ′″ of the molded article  2 . Balancing of cooling rates may be further implemented using two methods of various embodiments of the present invention:
       (a) increasing the initial cooling rate (for example, by increasing the cooling temperature) to ensure that the various portions  2 ′,  2 ″,  2 ′″ of the molded article  2  reach a target exit temperature at substantially the same time. In some embodiments of the present invention, this substantially same time substantially coincide with an instance of time when the molded article  2  is ready for ejection from the post-mod device  15 . In other words, the balancing may include controlling an initial cooling rate to decrease a temperature differential between a just-molded article  2  and cooling media   (b) Initially cooling the molded article  2  at a first temperature, then at a switch point commencing cooling at a second temperature; to ensure that the various portions  2 ′,  2 ″,  2 ′″ of the molded article  2  reach the target exit temperature at substantially the same time. In some embodiments of the present invention, this substantially same time substantially coincide with an instance of time when the molded article  2  is ready for ejection from the post-mod device  15 .       
 
         [0063]    Accordingly, a technical effect of some embodiments of the present invention leads to reduced slow-cooling induced defects (ex. crystallinity, ovality, etc.). Another technical effect of the embodiments of the present invention is that the molded article  2  reaches a target exit temperature at a point of time that substantially coincides with a point in time when the molded article  2  is removed from the post-mold device  15 . 
         [0064]    The description of the embodiments provides examples of the present invention, and these examples do not limit the scope of the present invention. For example, balancing of cooling rates will be specific to both molded article (e.g. preform) design and molding cycle time. It is understood that the scope of the present invention is limited by the claims. The concepts described above may be adapted for specific conditions and/or functions, and may be further extended to a variety of other applications that are within the scope of the present invention. Having thus described the exemplary embodiments, it will be apparent that modifications and enhancements are possible without departing from the concepts as described. Therefore, what is to be protected by way of letters patent are limited only by the scope of the following claims: