Identifying quality molded article based on determination of plug blow

Disclosed is: (i) a method of a molding system, (ii) a method of a controller of a molding system, (iii) a method of an article of manufacture of a controller of a molding system, (iv) a method of a network-transmittable signal of a controller of a molding system, (v) a method of a molding system having a controller, (vi) an article made by usage of a method. The method includes an operation of identifying quality of the molded article that was molded in a mold based on a determination of whether a plug blew, at least in part, from a melt passageway to the mold prior to a molding material entering the mold.

RELATED APPLICATIONS

The following is a list of patent applications related to the instant application, in which the Applicant's references numbers corresponding to U.S. patent application Ser. Nos. 11/297,926, 11/347,302, 11/349,984 and U.S. patent application Ser. No. 11/502,945 respectively.

TECHNICAL FIELD

The present invention generally relates to, but is not limited to, molding systems and control mechanisms of molding systems, and more specifically the present invention relates to, but is not limited to, (i) a method of a molding system, (ii) a controller of a molding system, (iii) an article of manufacture of a controller of a molding system, (iv) a network-transmittable signal of a controller of a molding system, (v) a molding system having a controller, (vi) a modeled article manufactured by a method.

BACKGROUND

Examples of known molding systems are (amongst others): (i) the HyPET™ Molding System, (ii) the Quadloc™ Molding System, (iii) the Hylectric™ Molding System, and (iv) the HyMet™ Molding System (which is a metal-molding system), all manufactured by Husky Injection Molding Systems (www.husky.ca).

U.S. patent application Ser. No. 2002/0189781 (Inventor: Shibata et al; Published: Jun. 19, 2002) discloses a method for manufacturing a mold of a metal hot-runner injection molding machine. The method includes: (i) measuring a temperature gradient of metal disposed in a nozzle between heating means of the nozzle and a tip of the nozzle, (ii) selecting an area in the nozzle based on the measurement of the temperature gradient such that the metal in the nozzle upon a mold opening has a temperature at which a solidified condition of the metal can be stably maintained, said temperature being close to a melting temperature of the metal, and (iii) determining a gate cut portion in the area.

U.S. Pat. No. 6,529,796 (Inventor: Kroeger et al; Published: Mar. 4, 2003) discloses an injection mold apparatus that has multiple injection zones, each zone having at least one heater and at least one temperature sensor generating a temperature indicating signal. A power source provides power to the heaters. A controller controls the temperature of at least some of the zones. For efficiency, the controller has two separate processors, a data-receiving processor for receiving temperature indicating signal from each sensor as well as power signals, and a control processor for receiving data from the data-receiving processor and for controlling the amount of power provided to the heaters. Preferably, the control is in a housing, with the housing mounted directly on the mold. Modified PID calculations are utilized. Power calculations for the amount of power to the heaters utilizes a modulo based algorithm.

U.S. patent application Ser. No. 2003/0206991 (Inventor: Godwin et al; Published: Nov. 6, 2003) discloses an improved mold manifold and hot runner nozzle using thin film elements include at least one active or passive thin film element disposed along a melt channel between the manifold inlet and the hot runner nozzle. Preferably, the thin film element may comprise a thin film heater in direct contact with the molten resin and position to aid in the heat and flow management of the resin within the melt channel. Thin film temperature sensors, pressure sensors, and leak detectors may also be provided in the vicinity of the melt channel to enhance process control in the injection molding machine.

U.S. Pat. No. 6,533,021 (Inventor: Shibata et al; Published: Mar. 18, 2003) discloses a mold for a metal hot-runner injection molding machine. The mold includes a movable mold plate, a fixed mold plate having a nozzle for injection molten metal into said cavity, and a heating device disposed outside the nozzle for heating metal. A gate cut portion is situated in the nozzle between the heating device and the tip. A temperature measurement device is arranged adjacent to the gate cut portion for measuring the temperature of the metal in the gate cut portion. A heating control device is connected to the heating device for controlling a temperature of the nozzle on a basis of the temperature measurement device. A heat insulation device is arranged on the nozzle to cover at least an area where the gate cut portion is formed. By controlling the temperature of the nozzle, metal injection molding without runner can be made.

U.S. Pat. No. 6,649,095 (Inventor: Buja; Published: Nov. 18, 2003) discloses a method and apparatus for controlling a mold flow process using inner (impinge) and/or edge temperature sensors, wherein articles processed in a constraining mold cavity, having a constant melt “shrink” quality, can be obtained even with fluctuations in resin “melt” properties (flowability). At least one temperature-dependent output or “trigger” signal is sampled, and the level of the signal (e.g., temperature) initiates at least one step in the molding cycle. Using a sampling circuit, thermal waveforms are obtained from thermal sensor array data such that if a sequence of melt temperature set-point trigger times fluctuates outside control limits, then the process melt-flow is judged as a hotter/faster melt-flow or cooler/slower melt-flow injection process.

U.S. Pat. No. 6,666,259 (Inventor: Shibata et al; Published: Dec. 23, 2003) discloses a method for manufacturing a mold of a metal hot-runner injection molding machines. The method includes: (i) disposing at least one temperature control target point, as a reference for a temperature control by heating means for heating a nozzle, between the heating means and a tip of the nozzle, (ii) controlling said heating means such that upon a mold opening, at least a portion of metal adjacent to the heating means becomes a molten state and that a temperature of said temperature control target point is kept at a constant level which is lower than a melting point of the metal, (iii) measuring a temperature gradient between the heating means and the tip of the nozzle when the temperature of the temperature control target point is kept constant, (iv) selecting an area in the nozzle based on the measurement of the temperature gradient such that the metal in the nozzle upon a mold opening has a temperature at which a solidified condition of the metal can be stably maintained, said temperature being close to a melting temperature of the metal, and (v) determining a gate cut portion in the area.

U.S. patent application Ser. No. 2004/0032060 (Inventor: Yu; Published: Feb. 19, 2004) discloses a method of controlling a shut-off nozzle for hot runner systems of injection molding machines, the shut-off nozzle heaving a heating unit and a cooling unit around a gate tip thereof. The method includes the steps of: (i) heating a nozzle body to a predetermined high temperature by turning on a heater which is provided in the nozzle body, (ii) heating the gate tip having a nozzle gate, by turning on the heating unit provided around the gate tip, (iii) injecting a molten resin into a cavity of a mold through the nozzle gate, (iv) turning off the heating unit, after an injection of a predetermined amount of the molten resin into the cavity of the mold is completed, thus allowing the gate tip to start to cool, (v) operating the cooling unit provided around the gate tip, thus quickly cooling the gate tip, and (vi) opening the mold to remote a molded product from the cavity of the mold.

U.S. Pat. No. 6,936,199 (Inventor: Olaru; Published: Aug. 30, 2005) discloses an injection molding apparatus that includes a manifold having a manifold channel for receiving a melt stream of molten material under pressure and delivering the melt stream to a nozzle channel of a nozzle. A mold cavity receives the melt stream from the nozzle and the nozzle channel communicates with the mold cavity through a mold gate. A thermocouple is coupled to the mold core of the mold cavity in order to measure the temperature of the molten material in the mold cavity.

U.S. Pat. No. 6,938,669 (Inventor: Suzuki et al; Published: Sep. 6, 2005) discloses a mold-clamping process in which the mold is closed and (i) the injection-pressure increase (solidifying) process, (ii) the gate-melting process for heating the hot runner to melt the plug (metallic material) of the gate, (iii) the mold-lubricant coating process for spraying the lubricant onto the wall surface of the cavity, and (iv) the material-metering process are simultaneously carried out in parallel to each other. Thus, the molding cycle time can be reduced to a great extent.

SUMMARY

According to a first aspect of the present invention, there is provided a method of a molding system, including: an operation of identifying quality of a molded article that was molded in a mold based on a determination of whether a plug blow, at least in part, from a melt passageway to the mold prior to a molding material entering the mold.

According to a second aspect of the present invention, there is provided a method of a controller of a molding system, the controller including: a controller-usable medium embodying instructions being executable by the controller, the controller configured to be operatively coupled to the molding system, the instructions including: executable instructions for directing the controller to perform an operation of identifying quality of a molded article that was molded in a mold based on a determination of whether a plug blew, at least in part, from a melt passageway to the mold prior to a molding material entering the mold.

According to a third aspect of the present invention, there is provided a method of an article of manufacture of a controller of a molding system, the article of manufacture including: a controller-usable medium embodying instructions executable by the controller, the controller operatively coupled to the molding system, the instructions including: executable instructions for directing the controller to perform an operation of identifying quality of a molded article that was molded in a mold based on a determination of whether a plug blew, at least in part, from a melt passageway to the mold prior to a molding material entering the mold.

According to a fourth aspect of the present invention, there is provided a method of a network-transmittable signal of a controller of a molding system, the network-transmittable signal including: a carrier signal modulated to carry instructions executable by a controller operatively coupled to the molding system, the instructions including: executable instructions for directing the controller to perform an operation of identifying quality of a molded article that was molded in a mold based on a determination of whether a plug blew, at least in part, from a melt passageway to the mold prior to a molding material entering the mold.

According to a fifth aspect of the present invention, there is provided a method of a molding system, including: a controller, including: a controller-usable medium embodying instructions being executable by the controller, the controller operatively coupled to the molding system, the instructions including: executable instructions for directing the controller to perform an operation of identifying quality of a molded article that was molded in a mold based on a determination of whether a plug blew, at least in part, from a melt passageway to the mold prior to a molding material entering the mold.

According to a sixth aspect of the present invention, there is provided an article manufactured by a method, the method including: an operation of identifying quality of the molded article that was molded in a mold based on a determination of whether a plug blew, at lest in part, from a melt passageway to the mold prior to a molding material entering the mold.

A technical effect, amongst other technical effects, of the aspects of the present invention is improved operation of a molding system. Preferable embodiments of the present invention are subject of the dependent claims.

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

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1is a schematic representation of a molding system100(hereafter referred to as the “system100”) according to the first embodiment. Preferably the system100is a metal molding system. A method of the system100includes determining whether a plug110actually blew from a melt passageway112of the system100into a mold114. The plug110is also commonly called a “thermal plug”. The plug110may be solidified, but more likely the plug110is soft (as in, the plug110not 100% solidified). The system100includes a controller102that is operatively cooperative with the system100. The controller102includes a controller-usable medium104embodying instructions105that are executable by the controller102. The instructions105include executable instructions for directing the controller102to determine whether the plug110actually blew from the melt passageway112into the mold114. According to a variant, the instructions105are delivered to the controller102via a network-transmittable signal106that includes a carrier signal modulated to carry the instructions105. The network-transmittable signal106is transmittable over a network, such as the Internet so that the instructions105are receivable via an interface142of the controller102. According to another variant, the instructions105are delivered to the controller102via an article of manufacture108that includes a controller-usable medium embodying the instructions105. The article of manufacture108may be a CD (Compact Disk), floppy disk, flash memory, optical disk, etc. Detailed of the instructions105are described below. The article of manufacture108is interfaced (coupled) to an interface143of the controller102. The interfaces142,143are well known in the art. The controller102may include a display unit and/or a keyboard to assist operator (human) interfacing.

Preferably, the system100includes an extruder120(such as an injection unit). A machine nozzle122extends through a stationary platen124and connects the extruder120to a hot runner126. The hot runner126is mounted to the stationary platen124. The hot runner126is operatively coupled to a stationary side of the mold114. A movable side of the mold114is mounted to a movable platen128. Tie bars and clamping assemblies are not depicted since they may be conventional and thus well known to those skilled in the art.

A thermal sensor130(such as thermocouple) is positioned proximate of the melt passageway112. The thermal senor130is electrically connected (wired) to an interface140of the controller102. A heater132is coupled proximate of the melt passageway. The heater132is electrically connected (wired) to an interface141of the controller102. Preferably, the thermal sensor130and the heater132are positioned proximate of a drop134of the hot runner126. According to a variant, the thermal senor130is positioned proximate of a cooling structure (not depicted), and the cooling structure is used to form the plug in the melt passageway of the hot runner126.

Preferably, a dedicated thermal sensor and a dedicated heater are positioned proximate of each drop of the hot runner126, such as thermal sensor136, heater138, and drop139). The thermal senor130is electrically connected (wired) to an interface145of the controller102, while the heater138is electrically connected (wired) to an interface144of the controller102.

Preferably, the controller102includes a CPU (Central Processing Unit)150that is used to execute the instructions105. A bus152operatively connects the CPU150with the interfaces140to145, the controller-usable medium104and with a database154.

FIG. 2is a schematic representation of an operation200of the system100ofFIG. 1. The operation200is coded in programmed statements of the instructions105by using a programming language, such as (i) a high-level language (C++ or Java, etc) which is then translated to machine language or (ii) assembly/machine language of a particular processor used in the controller102. The instructions105are executable by the controller102ofFIG. 1. Operation202includes starting of the operation200and the control is transferred to operation204. Operation204includes directing the controller102to obtain a temperature reading of a thermal sensor (either senor130and/or sensor136but preferably both). Operation206includes directing the controller102to determine, after injection pressure has been applied to the plug110, whether the plug110blew from the melt passageway112and into the mold114(at least partial flow, full flow or no flow). The determination is preferably made or based on a comparison between the temperature of the thermal sensors130,136and a threshold.

Operation208includes directing the controller102to determine whether to control (adjust the heaters132,138) or to annunciate (to a human operator) or both control and annunciate: (i) if it is required to only annunciate, operational control of operation200is transferred to operation210, (ii) if it is required to only control, operational control of operation200is transferred to operation212and (iii) if it is required to control and to annunciate, operational control of operation200is transferred to operation212and210respectively.

Operation210includes directing the controller102to annunciate whether the plug110blew from the melt passageway112and into the mold114. Operation212includes adjusting thermal management (temperature of the heaters132,138) of the melt passageway112so that the plug110may blow in the next injection cycle, based on the determination of whether the plug110blew from the melt passageway112and into the mold114for the current cycle of injection of the system100.

Operational control is passed over to operation214in which: condition (i) an operator may decide to update the database154, condition (ii) automatic updating of the database154occurs, or condition (iii) no updating of the database154occurs. If conditions (i) or (ii) are selected, operational control is passed over to operation216. If condition (iii) is selected, operational control is passed over to operation220.

Operation216includes directing the controller102to determine a new threshold based on contents of a database154, the database154indicative of a temperature profile corresponding to types of molding material. Operational control is then passed over to operation218, which includes determining a new threshold based on contents of a database154, the database154indicative of historical data of temperature profiles corresponding to a type of molding material.

Operation220includes directing the controller102to determine whether to end the operation220or pass on operational control to operation202.

The instructions105include executable instructions for directing the controller102to determine whether the plug110actually blew (or was blown) from the melt passageway112into the mold114. According to a variant of the system100, the melt passageway112is defined by a drop134of hot runner126, and the hot runner126has a plurality of drops. Preferably, the determination of whether the plug110actually blew is based on a comparison between a measured temperature of a thermal sensor130and a threshold. The instructions105for directing the controller102may include additional programmed instructions, such as: (i) determining whether the plug110actually blew from the melt passageway112is based on a comparison between a measured temperature of the thermal senor130and a threshold, in which the comparison between the measured temperature and the threshold is an indication of whether at least one of partial-flow condition, full-flow condition, and no-flow condition had occurred, (ii) determining whether the plug110actually blew from the melt passageway112is based on a comparison between a measured temperature of the thermal sensor130and a threshold in which the threshold includes a temperature profile of the melt passageway112, (iii) determining whether the plug110actually blew from the melt passageway112is based on a comparison between a measured temperature of the thermal sensor130and a threshold, (iv) obtaining a temperature reading of the thermal sensor130in which the thermal sensor130is operatively connected to the controller102, (v) adjusting, based on the determination of whether the plug110blew from the melt passageway112, thermal management of the plug110disposed in the melt passageway112so that the plug110may blow from the melt passageway112into the mold114during a subsequent injection cycle of the system100, (vi) annunciating whether the plug110blew from the melt passageway112and into the mold114, (vii) determining a new threshold based on contents of the database154in which the database154is indicative of a temperature profile corresponding to types of molding material, (viii) obtaining a temperature reading of the thermal sensor130positioned proximate of the plug110disposed in the melt passageway112, and/or (ix) determining, after injection pressure has been applied to the plug110, whether the plug110blew from the passageway based on a comparison between the temperature of the thermal sensor130and a threshold.

FIG. 3is a schematic representation of the system100according to the second exemplary embodiment, in which a hot runner is not included and the machine nozzle122is coupled directly to the mold114.

FIG. 4is a schematic representative of temperature profiles along the melt passageway112of the system100ofFIG. 1. Three thermal graphs are depicted: (i) thermal graph400, (ii) thermal graph402and (iii) thermal graph404. For each thermal graph400,402,404, the x-axis is time and the y-axis is temperature. Curves410,412correspond to temperature profiles of respective thermal senors that have been placed in respective drops of a manifold of the hot runner126(the drops lead into the mold cavity of the mold114). Curves420,422correspond to respective temperature profiles of thermal sensors that have been placed proximate of respective cooling structures (such as, cooling rings) that are each placed at respective drops of the hot runner126. The cooling rings are used to form a plug in the melt passageway112(such as in the drop134of the hot runner126).

The thermal graph400depicts a contain in which plugs (such as the plug110) located in respective drops134and139of the hot runner126were blown out. The temperature of the cooling structure varies as a shot of hot molding material is injected into the mold cavity. Just before injection, the temperature is at the most highest point in the temperature profile. Just after the mold cavity becomes filled the temperature is at a lowest point in the temperature profile.

The thermal graph402depicts a condition in which one plug was not completely blown out from a drop while the other plug was completely blown out and as a result less flow was realized through that drop.

The thermal graph404depicts a condition in which one plug was blown out from a drop while the other plug was not. The profile of the curve422indicates that the thermal sensor of a cooling structure has experienced no thermal load (that is, there was no flow of molding material past the cooling structure) and hence there was no increase in temperature for the injection cycle (temperature remained relatively constant). The profile of the curve412of the drop (that is associated with the cooling structure that experienced no thermal load) indicates that the thermal sensor of the drop indicates limited thermal load. As a result of back filling the mold cavity, the hot molding material will eventually fill the mold cavity and the temperature of the drop slightly increases as a result.

FIG. 5is the schematic representation of an operation500of the molding system ofFIG. 1according to the third exemplary embodiment. The operation500is coded in programmed statements of the instructions105by using a programming language, such as (i) a high-level language (C++ or Java, etc) which is then translated to machine language, or (ii) assembly/machine language of a paricular processor that is used in the controller102; the instructions105are executable by the controller102ofFIG. 1. Operation500(which may also be called a method500) includes, preferably, operations501,502,504,506,508,510,512and/or514; operations501to514inclusive are included according to the preferred embodiment. Operation501is a modification of the operation208(operation208is described above in association withFIG. 2). Operation501includes directing the controller102to determine whether to pass control from operation206(which was described in connection toFIG. 2) to: (i) operation212(that is, to adjust the heaters132,138accordingly as described above), (ii) operation210(that is, to annunciate to a human operator accordingly, as described above), and/or (iii) operation502. Operation502includes directing the controller102to identify quality of the molded article600that was molded in the mold114based on a determination of whether the plug110blew, at least in part, from the melt passageway112to the mold114prior to the molding material entering the mold114. A technical effect of operation502is that the operator of the system100would not have to examine each molded article to make a determination of the quality of the molded article, and this arrangement would simplify and/or improve operation of the system100. Preferably, at least two possible operations may then be performed, such as execution of: (i) operation504of identifying whether the molded article600has questionable quality if the plug110did not blow, and/or (ii) operation506that includes identifying whether the molded article600has acceptable quality if the plug110did blow. Operation504may include annunciating that the molded article600has questionable quality (such as turning on a red-colored lamp). Operation506may include annunciating that the molded article600has acceptable quality (such as turning on a green-colored lamp). Preferably the determination of whether the plug110blew includes analyzing an output signal of the senor130and/or the senor136to determine whether the plug110blew into the mold114once a molding material is injected to the mold114from an extruder120(this determination is described above in connection withFIGS. 2 and 4); the extruder120is operatively coupled to the mold114, and the extruder120was used to prepare the molding material. The sensor130and the sensor136are positioned proximate to the plug110that is waiting to be ejected from the melt passageway112to the mold114. If desired, control may then pass to operation508of setting aside the molded article600if the plug110did not blow; more specifically, operation508includes executing: (i) operation510of removing the molded article600from the mold114if the molded article600was identified as having questionable quality, and (ii) operation512of placing the molded article600in a scrap pile. Optionally, operation510and operation512may be included in operation512of directing a robot (not depicted) to remove the molded article600from the mold114if the molded article600was identified as having questionable quality, and (ii) place the molded article600in a scrap pile.

The description of the exemplary embodiments provides examples of the present invention, and these examples do not limit the scope of the present invention. It is understood that the scope of the present invention is limited by the claims. The exemplary embodiments 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. It is to be understood that the exemplary embodiments illustrate the aspects of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims. The claims themselves recite those features regarded as essential to the present invention. Therefore, what is to be protected by way of letters patent are limited only by the scope of the following claims.