WO2013075230A1

WO2013075230A1 - Mold-tool system having control assembly to receive hold-time information associated with mold cavities that produced out-of-tolerance molded articles

Info

Publication number: WO2013075230A1
Application number: PCT/CA2012/050779
Authority: WO
Inventors: Joachim Johannes Niewels; Douglas James Weatherall
Original assignee: Husky Injection Molding Systems Ltd; Husky Injection Molding Systems SA
Current assignee: Husky Injection Molding Systems Ltd; Husky Injection Molding Systems SA
Priority date: 2011-11-22
Filing date: 2012-11-02
Publication date: 2013-05-30
Anticipated expiration: 2014-05-22

Abstract

Mold-tool system (100) comprising control assembly (102) configured to couple with mold gates (933) defined by mold interface (931), mold gates (933) configured to feed flowable resin to mold cavities (930) defined by mold assembly (918) configured to produce molded articles. Control assembly (102) having: mold-cavity closing sequence (105) indicating closing time of each of mold gates (933) control assembly (102) configured to: (i) read the closing sequence (105) indicating closing time of each of gates (933), (ii) close each of mold gates (933) in accordance with mold-cavity closing sequence (105) during hold cycle of mold assembly (918).

Description

MOLD-TOOL SYSTEM HAVING CONTROL ASSEMBLY TO RECEIVE HOLD-TIME INFORMATION ASSOCIATED WITH MOLD CAVITIES THAT PRODUCED OUT-OF-

TOLERANCE MOLDED ARTICLES TECHNICAL FIELD

Aspects generally relate to (and not limited to) mold-tool systems including (and not limited to) molding systems.

BACKGROUND

United States Patent Numbers 4279582, 4950143, 5556582, 5919492, 6001296, 62941 22, 6287107, 6294122, 6309208, 6343921 , 6343922, 6287107, 6554604, 7214048, 7270537, 7275923, and United States Patent Publication Numbers 2002/0086086, 2003/01 98702, 2005/01 00625, 2005/01 23641 are publically available documents that appear to generally disclose mold-tool systems and molding systems configured to fill mold cavities of a mold assembly.

SUMMARY

The inventors have researched a problem associated with known molding systems that inadvertently manufacture overweight and-or underweight molded articles or parts. After much study, the inventors believe they have arrived at an understanding of the problem and its solution, which are stated below.

For known molding systems having multiple mold cavities, the mold cavities are filled and then once a hold time is ended, all of the mold gates are closed at the same time (within a tolerance level). For molding of relatively smaller molded articles, such as water bottle screw-off caps (that is, closures) having a large surface area to volume ratio, the weight of the molded article depends on the dimensions of a mold cavity used to produce the molded article. This presents a problem for large cavitation molding of small molded articles (especially of closures), since the part weight resulting from using the mold cavities machined to the maximum and minimum material conditions are very close to the maximum and minimum tolerances for the part weight. Large cavitation molding involves mold assemblies that have a very large number of mold cavities, such as 96 mold cavities, etc. Closures are molded articles used for closing bottles, such as a water bottle for example. The result is that the distribution of part weights of molded articles produced using a large- cavitation injection-molding system is very broad, and the Cpk (Process Capability Index) is undesirably small, typically less than 1.3. In contrast, the molded articles made from molding cycle to molding cycle in a selected mold cavity of the mold assembly are very repeatable, with Cpk's of greater than 10. However, this compares unfavorably against the compression molding process, in which part weight Cpk is typically greater than 4.0, so that although the injection-molding process itself is more repeatable, the manufacturing tolerances realistically achievable today lower the Cpk of the product stream output from the multicavity injection-molding system to an unacceptably low level.

The factor with the largest influence over part weight in the injection-molding cycle is the hold time. This is illustrated in the graph depicted in FIG. 2B, where the part weight of a closure (molded article) is shown as a function of the hold time. For example, for a nominal part weight of 2.14 grams (g), a hold time of 1.1 seconds (s) is used. The slope of the line (curve) around the nominal part weight is about 0.15g/s (grams per second), so that in order to make a molded article heavier by 0.05 grams (half the typical part weight tolerance) an increase of about 0.3 seconds in hold time would be required.

According to one aspect that is used to resolve the above identified problem(s), there is provided a mold-tool system (100), comprising: a control assembly (102) being configured to couple with mold gates (933) defined by a mold interface (931 ), the mold gates (933) being configured to feed, in use, a flowable resin to mold cavities (930) defined by a mold assembly (918), the mold assembly (918) being configured to produce molded articles, the control assembly (102) having: a mold-cavity closing sequence (105) indicating closing time of each of the mold gates (933), and the control assembly (102) being configured to: (i) read a mold-cavity closing sequence (105) indicating closing time of each of the mold gates (933), and (ii) close each of the mold gates (933) in accordance with the mold-cavity closing sequence (105) during a hold cycle of the mold assembly (918).

According to another aspect that is used to resolve the above identified problem(s), there is provided a method of closing mold gates (933) defined by a mold interface (931 ), the mold gates (933) being configured to feed, in use, a flowable resin to mold cavities (930) defined by a mold assembly (918), the mold assembly (918) being configured to produce molded articles, the method comprising: (A) reading a mold-cavity closing sequence (105) indicating closing time of each of the mold gates (933). The solution provides the following advantage: an output of molded articles, from the mold assembly, have a more consistent part weight and/or part dimension. For example, if the hold time of individual mold cavities is controlled to better than 0.02 seconds (for example), the resulting Cpk is as high as that of the process itself (i.e. greater than 10). With a part weight repeatability of such magnitude, the weight is lowered to close to the bottom of the specification (weight tolerance for the molded article) thus reducing the amount of resin used to produce the molded articles, and thus reduce costs and improve marketplace competitiveness (which provides another good advantage for users of molding systems). Other aspects and features of the non-limiting embodiments will now become apparent to those skilled in the art upon review of the following detailed description of the non-limiting embodiments with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

The non-limiting embodiments will be more fully appreciated by reference to the following detailed description of the non-limiting embodiments when taken in conjunction with the accompanying drawings, in which:

FIGS. 1 , 2A, 2B, 2C, 3, 3, 4, 5, 6, 7A, 7B, 7C, 7D, 8 depict, at least in part, schematic representations of examples of a mold-tool system (100).

The drawings are not necessarily to scale and may be illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details not necessary for an understanding of the embodiments (and/or details that render other details difficult to perceive) may have been omitted.

DETAILED DESCRIPTION OF THE NON-LIMITING EMBODIMENT(S)

FIGS. 1 , 2A, 2B, 2C, 3, 3, 4, 5, 6, 7A, 7B, 7C, 7D, 8 depict, at least in part, the schematic representations of examples of a mold-tool system (100) for use with a molding system (900). The mold-tool system (100) and the molding system (900) may include components that are known to persons skilled in the art, and these known components will not be described here. It will be appreciated that for the purposes of this document, the phrase "includes (but is not limited to)" is equivalent to the word "comprising." The word "comprising" is a transitional phrase or word that links the preamble of a patent claim to the specific elements set forth in the claim that define what the invention itself actually is. The transitional phrase acts as a limitation on the claim, indicating whether a similar device, method, or composition infringes the patent if the accused device (etc) contains more or fewer elements than the claim in the patent. The word "comprising" is to be treated as an open transition, which is the broadest form of transition, as it does not limit the preamble to whatever elements are identified in the claim.

FIG. 1 depicts the schematic representation of an example of the molding system (900) having the mold-tool system (100). According to the example depicted in FIG. 1 , the molding system (900) includes (and is not limited to): (i) an extruder assembly (902), (ii) a clamp assembly (904), (iii) a runner system (916), and/or (iv) a mold assembly (918). By way of example, the extruder assembly (902) is configured, to prepare, in use, a heated, flowable resin, and is also configured to inject or to move the resin from the extruder assembly (902) toward the runner system (916). Other names for the extruder assembly (902) may include injection unit, melt-preparation assembly, etc. By way of example, the clamp assembly (904) includes (and is not limited to): (i) a stationary platen (906), (ii) a movable platen (908), (iii) a rod assembly (910), (iv) a clamping assembly (912), and/or (v) a lock assembly (914). The stationary platen (906) does not move; that is, the stationary platen (906) may be fixedly positioned relative to the ground or floor. The movable platen (908) is configured to be movable relative to the stationary platen (906). A platen-moving mechanism (not depicted but known) is connected to the movable platen (908), and the platen-moving mechanism is configured to move, in use, the movable platen (908). The rod assembly (910) extends between the movable platen (908) and the stationary platen (906). The rod assembly (910) may have, by way of example, four rod structures positioned at the corners of the respective stationary platen (906) and the movable platen (908). The rod assembly (910) is configured to guide movement of the movable platen (908) relative to the stationary platen (906). A clamping assembly (912) is connected to the rod assembly (910). The stationary platen (906) supports the position of the clamping assembly (912). The lock assembly (914) is connected to the rod assembly (910), or may alternatively be connected to the movable platen (908). The lock assembly (914) is configured to selectively lock and unlock the rod assembly (910) relative to the movable platen (908). By way of example, the runner system (916) is attached to, or is supported by, the stationary platen (906). The runner system (916) includes (and is not limited to) a mold-tool system (100). The molding system (900) may include (and is not limited to) the mold-tool system (100). The runner system (916) is configured to receive the resin from the extruder assembly (902). By way of example, the mold assembly (918) includes (and is not limited to): (i) a mold-cavity assembly (920), and (ii) a mold-core assembly (922) that is movable relative to the mold- cavity assembly (920). The mold-core assembly (922) is attached to or supported by the movable platen (908). The mold-cavity assembly (920) is attached to or supported by the runner system (916), so that the mold-core assembly (922) faces the mold-cavity assembly (920). The runner system (916) is configured to distribute the resin from the extruder assembly (902) to the mold assembly (918).

In operation, the movable platen (908) is moved toward the stationary platen (906) so that the mold-cavity assembly (920) is closed against the mold-core assembly (922), so that the mold assembly (918) may define a mold cavity configured to receive the resin from the runner system (916). The lock assembly (914) is engaged so as to lock the position of the movable platen (908) so that the movable platen (908) no longer moves relative to the stationary platen (906). The clamping assembly (912) is then engaged to apply a camping pressure, in use, to the rod assembly (910), so that the clamping pressure then may be transferred to the mold assembly (918). The extruder assembly (902) pushes or injects, in use, the resin to the runner system (916), which then the runner system (916) distributes the resin to the mold cavity structure defined by the mold assembly (918). Once the resin in the mold assembly (918) is solidified, the clamping assembly (912) is deactivated so as to remove the clamping force from the mold assembly (918), and then the lock assembly (914) is deactivated to permit movement of the movable platen (908) away from the stationary platen (906), and then a molded article may be removed from the mold assembly (918).

With reference to all of the FIGS, generally speaking, the mold-tool system (100) is used for operating a mold interface (931 ) defining the mold gates (933). The mold gates (933) are configured to feed, in use, a flowable resin to mold cavities (930) defined by the mold assembly (918). The mold assembly (918) is configured to produce molded articles, such as PET (polyethylene terephthalate) preforms. FIGS. 2A and 2C depict examples of open-loop control of the mold-tool system (100), and their operations are described below. FIGS. 3, 4, 5 depict examples of closed-loop control of the mold-tool system (100), and their operations are described below.

Referring now to FIG. 2A, there is depicted the schematic representation of the mold-tool system (100) in accordance with an example. The mold-tool system (100) includes (and is not limited to): the control assembly (102). The control assembly (102) is configured to couple with the mold gates (933). FIGS. 7A, 7B, 7C, 7D, 8 depict specific examples of the manner or arrangement in which the control assembly (102) is configured to couple with the mold gates (933).

Returning back to FIG. 2A, the control assembly (102) may include, by way of example, a programmable controller system, such as of the type (for example) manufactured by SIEMENS (Germany), ROCKWELL AUTOMATION (USA), etc, and any functional equivalent. The control assembly (102) may be a digital-based controller or may be an analogue-based controller, or a combination thereof. The control assembly (102) provides a system that monitors and affects the operational conditions of a given dynamical system, such as the mold assembly (918). The operational conditions are referred to as output variables of the mold assembly (918) that can be affected by adjusting certain input variables of the mold assembly (918). The control assembly (102) is configured to direct activities of the mold assembly (918), either by way of open-loop control or closed-loop control process. The control assembly (102) may be implemented using mechanical systems, or electrical (electronic) systems, or a combination of both mechanical systems and electronic systems. Pneumatic systems may be used as well for transmitting information and control using pressure. However, modern control systems in industrial settings now rely on computers, controllers, programmable logic controllers, etc, for implimenting the control assembly (102), with the addition of software (that is, processor- executable instructions) and/or specialized circuits, as required to implement the functions described for the control assembly (102). It is relatively easier to implement complex control algorithms (that is, controller-executable instructions) on the control assembly (102) having a computer (electronic) system rather than using a mechanical system. The control assembly (102) may include, by way of example: a processor and a processor-usable memory that tangibly embodies processor-executable instructions. The processor- executable instructions are configured to direct operation of the processor. The control assembly (102) may have input modules and output modules that permit interfacing of the control assembly (102) with the mold assembly (918). The processor-executable instructions may be constructed using high-level programmed instructions that are compiled using software tools to generate the processor-executable instructions.

The mold-tool system (100) includes (and is not limited to) the control assembly (102). The control assembly (102) is configured to couple with the mold gates (933) defined by the mold interface (931 ). The mold gates (933) are configured to feed, in use, a flowable resin to the mold cavities (930) defined by the mold assembly (918). The mold assembly (918) is configured to produce molded articles. The control assembly (102) has (and is not limited to): a mold-cavity closing sequence (105). The mold-cavity closing sequence (105) indicates closing time of each of the mold gates (933). The control assembly (102) is configured to: (i) read the mold-cavity closing sequence (105) indicating closing time of each of the mold gates (933), and (ii) close each of the mold gates (933) in accordance with the mold-cavity closing sequence (105) during a hold cycle of the mold assembly (918). The mold-cavity closing sequence (105) indicates closing time of each of the mold gates (933) for a case where each of the mold cavities (930) receive, in use, a weight of solidified resin being within an acceptable weight-tolerance limit (802). In this manner, unwanted flowable resin is prevented from entering each of the mold cavities (930) through the mold gates (933) after the mold gates (933) are closed.

The mold-cavity closing sequence (105) may be determined in a number of ways, which are explained below. One way, for example, is to manually measure the weight of each molded article made by the mold cavities (930), and then iteratively adjust the mold-cavity closing sequence (105) until the desired result is achieved for another molding cycle of the molding system (900). The molded articles are identified or associated with each mold cavity (930) or associated with a grouping of mold cavities (930).

It will be appreciated that in addition to the control assembly (1 02), a method is provided. The method is for closing the mold gates (933). The method includes (and is not limited to): (A) reading the mold-cavity closing sequence (105) indicating closing time of each of the mold gates (933). The mold-cavity closing sequence (105) indicates closing time of each of the mold gates (933) for a case where each of the mold cavities (930) receive, in use, a weight of solidified resin being within an acceptable weight-tolerance limit (802), and (B) closing each of the mold gates (933) in accordance with the mold-cavity closing sequence (105) during a hold cycle of the mold assembly (918). The method is executed by the controller (10).

The control assembly (102) is configured to provide hold-time fields (104). The hold-time fields (104) tangibly embodies (holds, stores) the mold-cavity closing sequence (105). It will be appreciated that the mold-cavity closing sequence (105) may be introduced to the control assembly (102) by many ways (such as, manually entered via a keyboard, or received from a computer system, or other assembly). A field, such as the hold-time fields (104), is defined as a space allocated for holding or retaining a particular item of information. A field may be found on a display screen (flat panel screen, human-machine interface, etc) of the control assembly (102), and/or may be found in a controller-readable memory system of the control assembly (102). The hold-time fields (104) are configured to receive (either manually or automatically) and retain hold-time information for the mold cavities of the mold assembly (918), either for each mold cavity or for groupings of mold cavities. The hold-time fields (104) are associated with mold cavities (930) of the mold assembly (918), which may include either each mold cavity or a grouping of mold cavities. The hold-time information is configured to set duration of hold times of the each of the mold cavities (930) and/or for each of grouping of mold cavities (930) (both ways are functionally equivalent). The hold-time information is used to indicate the length of time in which a flowable resin is held in a mold cavity (or grouping of mold cavities) under pressure before the mold gate is closed so as to isolate the mold cavity (or grouping of mold cavities) from further pressure. Then the resin in the mold cavity may further solidify (continue in the process of solidifying) and produce a molded article. The hold-time information is usable for setting occurrence of a time to close the mold gates (933) in accordance with a gate-closing sequence during an upcoming molding cycle of the mold assembly (918). Generally speaking, the hold-time fields (104) are associated with mold cavities (930) of the mold assembly (918). Specifically, the hold-time fields (104) receive and hold the hold-time information that are associated with mold cavities (930) that produced the out-of-tolerance molded articles (800). The hold-time fields (104) may be populated manually or automatically (electronically). For example, the hold-time fields (104) may be populated by an operator of the mold assembly (918). Alternatively, the hold-time fields (104) may be received from another assembly, as described below with connection to FIG. 4. The out-of- tolerance molded articles (800) each have a detected (measured) weight that is outside an acceptable weight-tolerance limit (802). The acceptable weight-tolerance limit (802) is depicted, by way of example, in FIG. 2B. The acceptable weight-tolerance limit (802) may include an upper limit, and/or may include a lower limit, as depicted in FIG. 2B. The acceptable weight-tolerance limit (802) indicates that the weight of the molded article is within weight tolerance limits; that is, the molded article is not overweight or not underweight.

Referring now to FIG. 2B, there is depicted an option for initially setting up the operation of the mold assembly (918), which is to use a look-up table (806). The look up table (806) indicates hold time versus weight of molded article. The horizontal axis (808) indicates hold time in seconds. The vertical axis (810) indicates weight of the molded article. Curve (812) indicates the relationship of the hold time versus weight of the molded article for the mold cavities of the mold assembly (918) of FIG. 1 . For example, if the desired weight of the molded article is 2.19 grams, then the hold time, for each mold cavity (930), should be approximately 1.45 seconds in accordance with the look-up table (806) of FIG. 2B. The range of acceptable weights that would be considered to be in tolerance (that is, acceptable) would be from 2.18 grams (g) to 2.2 grams. The look-up table approach is useful for obtaining an approximate starting point for a hold time for the mold cavities of the mold assembly (918). That is, for the initial condition, the hold time for each mold cavity is identical. However, in time, it is expected that the hold time for the mold cavities will change as may be required so that each mold cavity produced molded articles that are within the acceptable weight tolerance limits. The hold time determined by using the look-up table (806) is inputted into the hold-time fields (104) provided by the control assembly (102). It will be appreciated that the vendor of mold assembly (918) may provided the table (806) or the user of the mold assembly (918) may determine the information of table (806) by trial and error.

Referring back to FIG. 2A, the open-loop control of the mold-tool system (100) includes (and is not limited to): having an operator of the mold-tool system (100) obtain the detection information (804). The detection information (804) includes (and is not limited to): a measured weight of the molded articles. It may be desired to measure (either manually or automatically) the weights of each molded article that is made by the mold assembly (918). Then the weights and the mold identification is analyzed (either manually or automatically) in order to determine an update (manually or automatically) for the hold times for various mold cavities that produced molded articles that were underweight or overweight. Then the determined (calculated) hold times (for the selected mold cavities or grouping of mold cavities) are inserted (manually or automatically) into the hold-time fields (104). In this way, the hold-time fields (104) are updated. The detection information (804) includes (and is not limited to): mold-cavity identifiers found (indicated) on each molded article. The mold-cavity identifiers identify specific mold cavities (or groups of mold cavities) that produced the molded articles that were weighed. In this approach, the detection information (804) includes pairs of recorded data: (i) the weight of the molded article, and (ii) the identifier of the mold cavity (or group of mold cavities) that produced the molded article that was weighed. It will be appreciated that the mold cavities are configured to imprint a unique identifier or indicia to the molded article. Alternatively, a grouping of mold cavities may imprint a group identifier to the molded articles produced by the grouping of mold cavities (grouped by row, column, etc). It will be appreciated that the detection information (804) is collected automatically as depicted in FIG. 2A. The detection information (804) is collected automatically as depicted for the examples depicted in FIGS. 2C, 3, 4, 5. Referring back to FIG. 2A, once the detection information (804) is assembled (manually), an operator reviews the data contained in the detection information (804), and determines (either by experience or by consulting with the vendor of the mold assembly (918)) a new hold time for selected mold cavities that produced molded articles that were out of tolerance (the weight tolerance is depicted in FIG. 2B). The hold-time information (806) includes the new hold times, which are then inputted, by an operator for the case of FIG. 2A for example, to the hold-time field (104) of the control assembly (102). The control assembly (102) is further configured to close the mold gates (933) during the upcoming molding cycle in a sequence that is in accordance with the hold-time information received into the hold-time field (104) (that is, the operator inputted new hold times for selected mold cavities), so that after the upcoming molding cycle is completed, the detected weight for each new molded articles produced by the mold cavities (930) are within the acceptable weight-tolerance limit (802). For any given molding cycle, if there are any additional unacceptable new molded articles that are not within acceptable weight-tolerance limit (802), then holdtime information (and thus gate- closing time information) of the mold cavities associated with producing any unacceptable new molded articles is determined so that those mold gates may be closed appropriately, and so that the mold assembly (918) may then avoid producing any further unacceptable molded articles going forward for another molding cycle. It will be appreciated that several reiterations of the molding cycle of the mold assembly (918) may be required to achieve the state in which all of the molded articles that are produced are all (each) within the acceptable weight-tolerance limit (802). It will be appreciated that the hold times for each mold cavity and/or grouping of mold cavities may change from the initially set amount of time as initially determined with reference to FIG. 2B. It will be appreciated that several iterations may be needed; that is, the molded articles may need to be weighed once again and then new hold times may need to be determined and inputted (manually or automatically) into the control assembly (102) via the hold-time field (104). It will be appreciated that the long dashed line connecting: (i) the detection information (804) and the hold-time information (806), (ii) leading into the detection information (804), and (iii) leading out from the hold-time information (806) to the hold-time field (1 04), all represent manual operations performed by the operator or user. FIG. 2C depicts an example of the control assembly (102) used in an open-loop control mode. According to the example depicted by FIG. 2C, the control assembly (102) includes (and is not limited to): a mold-gate control assembly (700), and a vision-and-weight- detection assembly (702). The mold-gate control assembly (700) is configured to control the mold gate (933). The vision-and-weight-detection assembly (702) is configured to receive, from the mold assembly (918), all (or a selected number) of the molded articles produced for a given molding cycle, which may include any out-of-tolerance molded article (800), and in-tolerance molded articles (not depicted). The mold assembly (918) drops the molded articles to a conveyer assembly (not depicted and known). Alternatively, a robot assembly (not depicted and known) picks the molded articles from the mold assembly (918) and then drops the molded articles to the conveyer assembly. The conveyer assembly is configured to deliver the molded articles to the vision-and-weight-detection assembly (702). The vision- and-weight-detection assembly (702) is configured to use a vision-detection system (such as a camera) to identify or determine the mold-cavity identifier of the mold cavity (930) that produced the molded article. It will be appreciated that the definition of "the identification of the mold-cavity identifier" includes a mold-cavity identifier that identifies a selected grouping of mold cavities (either organized by rows, or columns, etc). The vision-and-weight- detection assembly (702) is also configured to weigh the molded article. The vision-and- weight-detection assembly (702) is also configured to capture the information (that is, weight of the molded article, and mold-cavity identifier that produced the molded article). The vision-and-weight-detection assembly (702) is also configured to automatically collect a data file, which is identified as the detection information (804). It will be appreciated that the vision-and-weight-detection assembly (702) includes a processor unit, memory and executable code configured to execute the functions described for the vision-and-weight- detection assembly (702). The detection information (804) is captured or entered automatically into a weight and weight-and-cavity-identification field (704), which is associated with the vision-and-weight-detection assembly (702). The detection information (804), in accordance with FIG. 2C, is provided (such as printed out as hard copy report or presented on a computer display) that indicates the information collected by the vision-and- weight-detection assembly (702). Then an operator may refer to this report or information, manually determine an appropriate update for the hold time, and then manually enter a new value for the hold-time information (806) into the hold-time field (104) of the mold-gate control assembly (700). Now a new molding cycle may be executed and the new molded articles that are produced will be in a better condition to satisfy the weight tolerance limits of FIG. 2B. Once again, if this is not the case, then the hold times for unacceptable molded articles may be recalculated and entered to the hold-time field (104). It will be appreciated that the long dashed line connecting the detection information (804) and the hold-time information (806) represents a manual operation (performed by the operator or user).

FIG. 3 depicts an example of the control assembly (102) used in a closed-loop control mode. According to the example depicted by FIG. 3, the control assembly (102) includes (and is not limited to): the same assemblies and systems depicted in FIG. 2C, with the addition that the mold-gate control assembly (700) and the vision and vision-and-weight- detection assembly (702) are connected by a communications link (such as a network, etc), so that the detection information (804) is transferred (automatically) from the vision and vision-and-weight-detection assembly (702) to the mold-gate control assembly (700). In addition, the mold-gate control assembly (700) is configured to include a conversion field (706) that receives the detection information (804). The mold-gate control assembly (700) is configured to compute the hold-time information (806) based on an algorithm (executable instructions) that inputs the detection information (804), and then places the hold-time information (806) into the hold-time field (104). The mold-gate control assembly (700) includes a memory unit that tangibly embodies the executable instructions that are executable by a processor, to execute the functions described above in connection with the conversion field (706).

FIG. 4 depicts another example of the control assembly (102) for another closed-loop control mode. According to the example depicted by FIG. 4, the control assembly (102) includes (and is not limited to): the same assemblies and systems depicted in FIG. 3. The mold-gate control assembly (700) and the vision-and-weight-detection assembly (702) are connected by a communications link (a network, etc). The vision-and-weight-detection assembly (702) includes the weight-and-cavity-identification field (704) and the conversion field (706). The vision-and-weight-detection assembly (702) is configured to compute the hold-time information (806) using the conversion field (706). The communications link transmits the hold-time information (806) from the vision-and-weight-detection assembly (702) to the mold-gate control assembly (700). It will be appreciated that the vision-and- weight-detection assembly (702) includes a memory unit that tangibly embodies the executable instructions that are executable by a processor, to execute the functions described above in connection with the conversion field (706). FIG. 5 depicts another example of the control assembly (102) used in another closed-loop control mode. According to the example depicted by FIG. 5, the control assembly (102) incorporates the functions of the mold-gate control assembly (700) and the vision-and- weight-detection assembly (702). The control assembly (102) includes (and is not limited to): the weight-and-cavity-identification field (704), the conversion field (706), and the hold- time field (104). The control assembly (102) includes a memory unit that tangibly embodies the executable instructions that are executable by a processor, to execute tasks for manipulation of the weight-and-cavity-identification field (704), the conversion field (706), and the hold-time field (104) as described above in connection to FIGS. 3 and 4.

FIG. 6 depicts an example, in which the control assembly (102) is coupled to a plurality of mold cavities (930). The plurality of mold cavities (930) includes a mold cavity (930A), a mold cavity (930B), a mold cavity (930C), and a mold cavity (930D). It will be appreciated that there may be any appropriate number of mold cavities, such as 48, 96, etc. The mold interface (931 ) defines or provides a plurality of mold gates (933). A melt-distribution path, (known and not depicted) is provided by (for example) the runner system (916) of FIG. 1. The melt-distribution path (or branches) provides, in use, a flowable resin to each of the mold gates (933). And the mold gates (933) feed the flowable resin to the plurality of mold cavities (930). The control assembly (102) is configured to couple with the mold gates (933), and the control assembly (102) is configured to selectively control closing of the mold gates (933) so that stoppage of a flow of a flowable resin to the mold cavities (930) during (that is, at the end of) a hold cycle of the mold assembly (918), so that a weight of solidified resin in the mold cavities (930) is controlled to be within an acceptable weight-tolerance limit (802). A gate-closing sequence is described in connection with FIGS. 2A, 2C, 3, 4, and 5. The hold cycle of the mold assembly (918) is a duration in time in which: (i) the mold gates (933) remain open and in fluid communication with the mold cavities (930), and (ii) a device, such as the extruder assembly (902) of FIG. 1 , for example, or a shooting pot assembly (known and not depicted), continues to exert a pressure (typically called the hold pressure) on the flowable resin received and contained in the mold cavities (930). During the hold cycle, the resin in the mold cavities (930) changes state from flowable to semi- solidified to solidified (at least in part). At the end of the hold cycle, the mold gates (933) are closed thus isolating the flowable resin located in the melt-distribution path or branches (of the runner system (916)), from the partially solidified resin located in the mold cavities (930). It will be appreciated that the sequence for closing the mold gates (933) may occur in any order that may be required, so that the weight of the molded articles produced by the mold cavities (930) of the mold assembly (918) are within the acceptable weight-tolerance limit (802). If so required, the molding cycle of the mold assembly (918) may be repeated as may times as may be required to achieve the acceptable weights for the molded articles relative to the acceptable weight-tolerance limit (802).

Generally speaking, the mold-tool system (1 00) is set up so that the mold gates (933) are closable by a valve-closing mechanism. Examples (and not limited thereto) of the valve- closing mechanism are depicted in FIG. 7A, 7B, 7C, 7D, which depict the valve stem (202), or FIG. 8, which depicts the plug-formation assembly (208). It will be appreciated that the manner in which the mold gates (933) are closed is not relevant, provided that the mold gates (933) may be controllably closed by the control assembly (102).

In accordance with an option (by way of example), the mold gates (933) may be grouped by a hierarchical order, such as by rows of mold gates (933), or by columns of mold gates (933), or by quadrants of rows and columns of mold gates (933), etc. The control assembly (102) is configured to close the mold gates (933) in accordance with and arrangement in which the mold gates (933) are grouped by a hierarchical order.

FIGS. 7A, 7B, 7C, 7D depict an example of the control assembly (102), which includes (and is not limited to): (i) a valve stem (202), for each mold gate (933), that is configured to be received by a nozzle assembly (200) of the runner system (916), (ii) a stem actuator (204), for each mold gate (933), that is coupled to a respective or selected one (or more) of valve stem (202), and (iii) a control unit (206), for each mold gate (933), that is connected to a respective or selected one or more of the stem actuator (204). The depicted example implies that each valve gate is controlled individually. It will be appreciated that controllably closing the mold gates (933) may be performed by closing a groups of the mold gates (933), by any suitable arrangement. It will be appreciated that the stem actuator (204) may be, by way of example, a hydraulic actuator, an electrical actuator, a mechanical actuator, a pneumatic actuator, or any suitable combination of the above mentioned actuators, etc. The control unit (206) may be, for example, a part of the molding-controller system (not depicted but known) that is configured to control operation of the molding system (900) of FIG. 1 , or may be a stand-alone controller that operates independently of the molding-controller system. According to a specific option for FIGS. 7A, 7B, 7C, 7D, the mold assembly (918) is valve gated, and the stem actuator (204) includes having individual electric motors controlling each valve stem (202). The electric motors are activated and close the valve stem (202) at the appropriate time during hold cycle of the mold assembly (918) so that the weight of solidifying resin in the mold cavity (930) is controlled precisely. According to this option, individual control for closing of each valve stem (202) (that is, for closing of each of the mold gates (933)) is accomplished so that each mold cavity (930) receives its desired amount of flowable resin so that when the molded articles are formed (solidified), they are each within the acceptable weight tolerance limit.

FIG. 7A depicts a case where the mold gates (933) are all closed, so that the flowable resin no longer is able to flow into each mold cavity (930) of the mold assembly (918).

FIG. 7B depicts a case where the mold gates (933) are all opened, so that the flowable resin is able to flow into each mold cavity (930) of the mold assembly (918).

FIG. 7C depicts a case where some of mold gates (933) are closed, so that the flowable resin is not able to flow into mold cavity (930A) and mold cavity (930C) of the mold assembly (918), while the mold cavity (930B) and the mold cavity (930D) continue to receive the flow of flowable resin. The control assembly (102) has closed the mold gates (933) for the mold cavity (930B) and the mold cavity (930D) because the mold cavity (930B) and the mold cavity (930D) have received the correct amount of flowable resin such that when the molded articles are removed from the mold cavity (930B) and the mold cavity (930D), they will have the correct weight (that is, the weight is within the acceptable weight tolerance limits). Otherwise, if the weights for these molded articles are not correct, for the next molding cycle, the control assembly (102) adjusts the hold times for mold cavity (930B) and the mold cavity (930D) so that the new molded articles that are made will be within the acceptable tolerance limit. FIG. 7D depicts a case where another mold gate (933) is closed, so that the flowable resin is not able to flow into mold cavity (930B), while the mold cavity (930D) continues to receive the flow of flowable resin. The molding cycle is repeated back to FIG. 7A.

FIG. 8 depicts another example of the control assembly (102), which is an alternative to the example depicted in FIGS. 7A, 7B, 7C, 7D (that is, valve stems not used). The control assembly (102), according to FIG. 8, includes (and is not limited to): a plug-formation assembly (208) configured to assist in formation of a plug to be positioned in the mold gates (933). By the of example, the plug-formation assembly (208) may include thermal cooling circuits and/or thermal heating circuits that are configured to be controlled by the control unit (206). The sequence, to be is executed by the control unit (206), determines which plugs are formed in which specific or selected one or more of the mold gates (933) in accordance with the gate closing sequence as indicated in the hold-time field (104) of the control assembly (102).

For example (and not limited thereto), by equipping the mold assembly with individually actuated (controllable) valve gates (for example) to close the mold gates that feed the mold cavities, then the hold time for each mold cavity (or grouping of mold cavities) is controlled by closing the mold gate (933) at the appropriate time, such that each mold cavity (or grouping of molding cavities) receives the required amount of resin (melt) or flowable molding material, such that when the molded article is weighed, the molded article has the desired weight (within a tolerance level). One benefit for this arrangement is improved part dimension repeatability from one position (mold cavity position) to the next position (one mold cavity to the next mold cavity), since parts that are lighter (smaller) get (are assigned or receive) a longer hold time (for the next molding cycle) in order to increase their weight, which would in turn result in less shrinkage. In addition, parts that are larger (heavier) get (are assigned or receive) shorter hold times (for the next molding cycle) leading to more shrinkage.

The solution provides the following advantage: an output of molded articles, from the mold assembly, that have a more consistent part weight and/or part dimension. In fact, if the hold time of individual mold cavities is controlled to better than 0.02 seconds (for example), the resulting Cpk is as high as that of the process itself (i.e. greater than 10). With a part weight repeatability of such magnitude, the weight is lowered to close to the bottom of the specification (for the molded article) thus reducing the amount of resin used to produce molded articles (and thus reduce costs and improve marketplace competitiveness), which provides another good advantage for users of molding systems.

Control Assembly (102)

According to one option, the control assembly (102) includes controller-executable instructions configured to operate the control assembly (1 02) in accordance with the description provided above. The control assembly (102) may use computer software, or just software, which is a collection of computer programs (controller-executable instructions) and related data that provide the instructions for instructing the control assembly (102) what to do and how to do it. In other words, software is a conceptual entity that is a set of computer programs, procedures, and associated documentation concerned with the operation of a controller assembly, also called a data-processing system. Software refers to one or more computer programs and data held in a storage assembly (a memory module) of the controller assembly for some purposes. In other words, software is a set of programs, procedures, algorithms and its documentation. Program software performs the function of the program it implements, either by directly providing instructions to computer hardware or by serving as input to another piece of software. In computing, an executable file (executable instructions) causes the control assembly (102) to perform indicated tasks according to encoded instructions, as opposed to a data file that must be parsed by a program to be meaningful. These instructions are machine-code instructions for a physical central processing unit. However, in a more general sense, a file containing instructions (such as bytecode) for a software interpreter may also be considered executable; even a scripting language source file may therefore be considered executable in this sense. While an executable file can be hand-coded in machine language, it is far more usual to develop software as source code in a high-level language understood by humans, or in some cases, an assembly language more complex for humans but more closely associated with machine code instructions. The high-level language is compiled into either an executable machine code file or a non-executable machine-code object file; the equivalent process on assembly language source code is called assembly. Several object files are linked to create the executable. The same source code can be compiled to run under different operating systems, usually with minor operating-system-dependent features inserted in the source code to modify compilation according to the target. Conversion of existing source code for a different platform is called porting. Assembly-language source code and executable programs are not transportable in this way. An executable comprises machine code for a particular processor or family of processors. Machine-code instructions for different processors are completely different and executables are totally incompatible. Some dependence on the particular hardware, such as a particular graphics card may be coded into the executable. It is usual as far as possible to remove such dependencies from executable programs designed to run on a variety of different hardware, instead installing hardware-dependent device drivers on the control assembly (102), which the program interacts with in a standardized way. Some operating systems designate executable files by filename extension or noted alongside the file in its metadata (such as by marking an execute permission in Unix-like operating systems). Most also check that the file has a valid executable file format to safeguard against random bit sequences inadvertently being run as instructions. Modern operating systems retain control over the resources of the control assembly (102), requiring that individual programs make system calls to access privileged resources. Since each operating system family features its own system call architecture, executable files are generally tied to specific operating systems, or families of operating systems. There are many tools available that make executable files made for one operating system work on another one by implementing a similar or compatible application binary interface. When the binary interface of the hardware the executable was compiled for differs from the binary interface on which the executable is run, the program that does this translation is called an emulator. Different files that can execute but do not necessarily conform to a specific hardware binary interface, or instruction set, can be represented either in bytecode for Just-in-time compilation, or in source code for use in a scripting language.

According to another option, the control assembly (102) includes application-specific integrated circuits configured to operate the assembly (1 08) in accordance with the description provided above. It may be appreciated that an alternative to using software (controller-executable instructions) in the control assembly (102) is to use an application- specific integrated circuit (ASIC), which is an integrated circuit (IC) customized for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC. Some ASICs include entire 32-bit processors, memory blocks including ROM, RAM, EEPROM, Flash and other large building blocks. Such an ASIC is often termed a SoC (system-on-chip). Designers of digital ASICs use a hardware description language (HDL) to describe the functionality of ASICs. Field- programmable gate arrays (FPGA) are used for building a breadboard or prototype from standard parts; programmable logic blocks and programmable interconnects allow the same FPGA to be used in many different applications. For smaller designs and/or lower production volumes, FPGAs may be more cost effective than an ASIC design. A field- programmable gate array (FPGA) is an integrated circuit designed to be configured by the customer or designer after manufacturing— hence field-programmable. The FPGA configuration is generally specified using a hardware description language (HDL), similar to that used for an application-specific integrated circuit (ASIC) (circuit diagrams were previously used to specify the configuration, as they were for ASICs, but this is increasingly rare). FPGAs can be used to implement any logical function that an ASIC could perform. The ability to update the functionality after shipping, partial re-configuration of the portion of the design and the low non-recurring engineering costs relative to an ASIC design offer advantages for many applications. FPGAs contain programmable logic components called logic blocks, and a hierarchy of reconfigurable interconnects that allow the blocks to be wired together— somewhat like many (changeable) logic gates that can be inter-wired in (many) different configurations. Logic blocks can be configured to perform complex combinational functions, or merely simple logic gates like AND and XOR. In most FPGAs, the logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory. In addition to digital functions, some FPGAs have analog features. The most common analog feature is programmable slew rate and drive strength on each output pin, allowing the engineer to set slow rates on lightly loaded pins that would otherwise ring unacceptably, and to set stronger, faster rates on heavily loaded pins on high-speed channels that would otherwise run too slow. Another relatively common analog feature is differential comparators on input pins designed to be connected to differential signaling channels. A few "mixed signal FPGAs" have integrated peripheral Analog-to- Digital Converters (ADCs) and Digital-to-Analog Converters (DACs) with analog signal conditioning blocks allowing them to operate as a system-on-a-chip. Such devices blur the line between an FPGA, which carries digital ones and zeros on its internal programmable interconnect fabric, and field-programmable analog array (FPAA), which carries analog values on its internal programmable interconnect fabric.

It will be appreciated that the assemblies and modules described above may be connected with each other as may be required to perform desired functions and tasks that are within the scope of persons of skill in the art to make such combinations and permutations without having to describe each and every one of them in explicit terms. There is no particular assembly, components, or software code that is superior to any of the equivalents available to the art. There is no particular mode of practicing the inventions and/or examples of the invention that is superior to others, so long as the functions may be performed. It is believed that all the crucial aspects of the invention have been provided in this document. It is understood that the scope of the present invention is limited to the scope provided by the independent claim(s), and it is also understood that the scope of the present invention is not limited to: (i) the dependent claims, (ii) the detailed description of the non-limiting embodiments, (iii) the summary, (iv) the abstract, and/or (v) description provided outside of this document (that is, outside of the instant application as filed, as prosecuted, and/or as granted). It is understood, for the purposes of this document, the phrase "includes (and is not limited to)" is equivalent to the word "comprising." It is noted that the foregoing has outlined the non-limiting embodiments (examples). The description is made for particular non-limiting embodiments (examples). It is understood that the non-limiting embodiments are merely illustrative as examples.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A mold-tool system (100), comprising:

a control assembly (102) being configured to couple with mold gates (933) defined by a mold interface (931 ), the mold gates (933) being configured to feed, in use, a flowable resin to mold cavities (930) defined by a mold assembly (918), the mold assembly (918) being configured to produce molded articles,

the control assembly (102) having:

a mold-cavity closing sequence (105) indicating a closing time of each of the mold gates (933), and

the control assembly (102) being configured to: (i) read the mold-cavity closing sequence (105) indicating the closing time of each of the mold gates (933), and (ii) close each of the mold gates (933) in accordance with the mold-cavity closing sequence (105) during a hold cycle of the mold assembly (918).

2. The mold-tool system (100) of claim 1 , wherein:

the mold-cavity closing sequence (105) indicates the closing time of each of the mold gates (933) for a case where each of the mold cavities (930) receive, in use, a weight of solidified resin being within an acceptable weight-tolerance limit (802), so that unwanted flowable resin is prevented from entering each of the mold cavities (930) through the mold gates (933) after the mold gates (933) are closed.

3. The mold-tool system (100) of claim 1 , wherein:

the control assembly (102) is configured to provide hold-time fields (104), the hold-time fields (104) is configured to receive hold-time information (806), the hold- time fields (104) is associated with the mold cavities (930) of the mold assembly (918).

4. The mold-tool system (100) of claim 2, wherein:

hold-time information (806) is configured to set duration of hold times of each of the mold cavities (930).

5. The mold-tool system (100) of claim 2 wherein: the hold-time information (806) is usable for setting occurrence of a time to close the mold gates (933) during an upcoming molding cycle of the mold assembly (918).

6. The mold-tool system (100) of claim 2, wherein:

the hold-time information (806) is associated with the mold cavities (930) of the mold assembly (918) that produced any out-of-tolerance molded articles (800) each having a detected weight is outside the acceptable weight-tolerance limit (802).

7. The mold-tool system (100) of claim 2, wherein:

the control assembly (102) is further configured to close the mold gates (933) during an upcoming molding cycle in a sequence being in accordance with the hold- time information (806) received, so that after the upcoming molding cycle is completed, a detected weight for each of new molded articles produced by the mold cavities (930) is within the acceptable weight-tolerance limit (802).

8. The mold-tool system (100) of claim 1 , wherein:

the control assembly (102) includes:

a mold-gate control assembly (700) configured to control the mold gates (933); and

a vision-and-weight-detection assembly (702) configured to:

determine identification of a mold cavity (930) that produced a molded article; and

weigh the molded article;

capture a weight of the molded article and identification of the mold cavity (930) that produced the molded article,

collect detection information (804), and

provide the weight of the molded article and the identification of the mold cavity (930) that produced the molded article.

9. The mold-tool system (100) of claim 2, wherein:

the control assembly (102) includes:

a mold-gate control assembly (700) configured to control the mold gates (933); a vision-and-weight-detection assembly (702) being configured to connect to the mold-gate control assembly (700) by a communications link; and

the vision-and-weight-detection assembly (702) is configured:

weigh the molded article;

collect detection information (804),

transfer the detection information (804) to the mold-gate control assembly (700),

wherein the mold-gate control assembly (700) is configured to:

include a conversion field (706) that receives the detection information

(804),

compute the hold-time information (806) based on an algorithm that inputs the detection information (804), and then places the hold-time information (806) into a hold-time field (104).

10. The mold-tool system (1 00) of claim 2, wherein:

the control assembly (102) includes:

a mold-gate control assembly (700) configured to control the mold gates (933);

a vision-and-weight-detection assembly (702) being configured to connect to the mold-gate control assembly (700) by a communications link; and

the vision-and-weight-detection assembly (702) is configured:

weigh the molded article;

collect detection information (804),

transfer the detection information (804) to the mold-gate control assembly (700), wherein the mold-gate control assembly (700) is configured to:

include a conversion field (706) that receives the detection information

(804),

compute the hold-time information (806) based on an algorithm that inputs the detection information (804), and then places the hold-time information (806) into a hold-time field (104),

the vision-and-weight-detection assembly (702) includes the weight and weight-and-cavity-identification field (704) and the conversion field (706), and

the communications link transmits the hold-time information (806) from the vision-and-weight-detection assembly (702) to the mold-gate control assembly (700).

11 . The mold-tool system (1 00) of claim 1 , wherein:

the control assembly (102) is configured to:

control the mold gates (933);

weigh the molded article;

capture a weight of the molded article and identification of the mold cavity (930) that produced the molded article;

collect detection information (804);

include a conversion field (706) that receives the detection information

(804);

compute a hold-time information (806) based on an algorithm that inputs the detection information (804), and then places the hold-time information (806) into a hold-time field (104); and

include the weight and weight-and-cavity-identification field (704), the conversion field (706), and the hold-time field (104).

12. The mold-tool system (1 00) of claim 1 , wherein:

the mold gates (933) are grouped by a hierarchical order, and

the control assembly (102) is configured to close the mold gates (933) in accordance with an arrangement in which the mold gates (933) are grouped by the hierarchical order.

13. The mold-tool system (1 00) of claim 1 , wherein:

the control assembly (102) includes:

a valve stem (202), for each of the mold gates (933), that is configured to be received by a nozzle assembly (200) of a runner system (916),

a stem actuator (204), for each of the mold gates (933), that is coupled to a respective valve stem (202), and

a control unit (206), for each mold gate (933), that is connected to a respective stem actuator (204).

14. The mold-tool system (1 00) of claim 1 , wherein:

the control assembly (102) includes:

a control unit (206); and

a plug-formation assembly (208) configured to assist in formation of a plug to be positioned in the mold gates (933),

the plug-formation assembly (208) includes:

thermal cooling circuits configured to be controlled by the control unit (206), ,

the control unit (206) is configured to determine which plugs are formed in the mold gates (933).

15. The mold-tool system (1 00) of claim 1 , wherein:

the mold gates (933) are closable by a valve-closing mechanism.

16. A molding system (900) having the mold-tool system (100) of any preceding claim.

17. A method of closing mold gates (933) defined by a mold interface (931 ), the mold gates (933) being configured to feed, in use, a flowable resin to mold cavities (930) defined by a mold assembly (918), the mold assembly (918) being configured to produce molded articles, the method comprising:

reading a mold-cavity closing sequence (105) indicating closing time of each of the mold gates (933), the mold-cavity closing sequence (105) indicating closing time of each of the mold gates (933) for a case where each of the mold cavities (930) receive, in use, a weight of solidified resin being within an acceptable weight- tolerance limit (802), so that unwanted flowable resin is prevented from entering each of the mold cavities (930) through the mold gates (933) after the mold gates (933) are closed; and

closing each of the mold gates (933) in accordance with the mold-cavity closing sequence (105) during a hold cycle of the mold assembly (918).