Patent Publication Number: US-2022212385-A1

Title: Manufacturing method and injection molding system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application 62/849,482, which was filed on May 17, 2019. 
    
    
     FIELD 
     The present disclosure relates to an injection molding system. 
     BACKGROUND 
     In the manufacturing of molded parts by an injection molding machine, an injection process of filling a resin into a mold after clamping the mold, a dwelling process of pressing the resin into the mold at a high pressure in order to compensate for a volume decrease due to solidification of the resin, a cooling process of keeping the molded part in the mold until the resin is solidified, and an ejecting process of ejecting the molded part from the mold are repeatedly performed. 
     In the above-described molding approach, a method that uses two molds with one injection molding machine in order to enhance productivity has been proposed. For example, WE 2018/0009146/Japanese patent publication No. 2018-001738/VN20160002505 are seen to discuss a system in which conveying devices  3 A and  3 B are arranged on both sides of an injection molding machine  2 . In this system, molded parts are manufactured while alternating a plurality of molds by the conveying devices  3 A and  3 B for the one injection molding machine  2 .  FIGS. 1-4  illustrate an injection molding system of US 2018/0009146/Japanese patent publication No. 2018-001738/VN20160002505. 
     Japanese patent publication No. H7-119012 discloses a system in which molded part ejecting apparatuses are arranged on both sides of an injection molding machine. In this system, in the injection molding machine, an injection process and a dwelling process can be performed on one mold, and a cooling process and an ejecting process can be performed by the molded part ejecting apparatus outside the injection molding machine on another mold. The molding operation proceeds while changing (alternating) the two molds between the injection molding machine and the molded part ejecting apparatus. 
     Generally, a mold is manufactured with a metal such as a steel material and can reach weights from several kilograms to several hundred kilograms. For a mold, to manufacture a molded part without a problem such as a burr and whose dimensional precision is high, molded parts are manufactured at high dimensional precision, and combined, and therefore sufficient precision is required from the mold opening/closing mechanism. Accordingly, the opening/closing mechanism is often expensive. 
     In the system of Japanese patent publication No. H7-119012, because the molded part is ejected outside the injection molding machine, it is necessary to provide a mold opening/closing mechanism for each ejecting apparatus. It is also necessary to provide a molded part ejecting mechanism for each ejecting apparatus. Accordingly, multiple mold opening/closing mechanisms and molded part ejecting mechanisms become necessary, and the cost of the system as a whole becomes expensive. 
     While the system of Japanese patent publication No. H7-119012 can enhance productivity compared to normal molding by executing the cooling process both inside and outside the injection molding machine, there is room for further improvement. For example, if the times for processes inside and outside the injection molding machine are respectively assigned to be half that of the overall molding process, productivity will be maximized. 
     Japanese patent publication No. H10-180797 discloses a technology about insert molding. Injection molding is performed after transferring a part into the mold, and the insert molding technology that performs integral molding of the relevant part and resin is widely known. However many parts to be inserted are prepared beforehand. 
     Until now, a technology that performs insert molding while alternating multiple molds was unknown. The equipment configuration that considers the productivity when performing insert molding while exchanging molds was not sufficiently considered. 
     SUMMARY 
     According to at least one aspect of the present disclosure, a method for manufacturing a molded part using one injection molding machine while changing between multiple molds includes a first step of performing, at a molding operation position in the injection molding machine, clamping, injection, and dwelling of a mold, a second step of conveying the mold from the molding operation position and performing a process of cooling the mold at a position different from the molding operation position, and a third step of conveying the mold to the molding operation position, opening the mold, and ejecting a molded part, wherein, before performing the first step for a first mold, a molded part previously ejected from a second mold is placed into the first mold opened in the third step. 
     This and other embodiments, features, and advantages of the present disclosure will become apparent upon reading the following detailed description of exemplary embodiments of the present disclosure, when taken in conjunction with the appended drawings, and provided claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view of an injection molding system according to an exemplary embodiment. 
         FIG. 2  is a side view of the injection molding machine. 
         FIG. 3  is an end view of a stationary platen, and a figure viewing from the arrow direction of the I-I line in  FIG. 2 . 
         FIG. 4  is a partial perspective view describing the configuration of the periphery of the molding operation position. 
         FIG. 5  is a flowchart illustrating an example of a control method of a molding system executed by the controller. 
         FIG. 6  illustrates details of the chuck. 
         FIG. 7  is an illustrative view of a chuck plate of another exemplary embodiment. 
     
    
    
     Throughout the figures, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components or portions of the illustrated embodiments. Moreover, while the subject disclosure will now be described in detail with reference to the figures, it is done so in connection with the illustrative exemplary embodiments. It is intended that changes and modifications can be made to the described exemplary embodiments without departing from the true scope and spirit of the subject disclosure as defined by the appended claims. 
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The present disclosure has several embodiments and relies on patents, patent applications and other references for details known to those of the art. Therefore, when a patent, patent application, or other reference is cited or repeated herein, it should be understood that it is incorporated by reference in its entirety for all purposes as well as for the proposition that is recited. 
     With reference to the drawings, the arrow symbols X and Y in each Figure indicate horizontal directions that are orthogonal to each other, and the arrow symbol Z indicates a vertical (upright) direction with respect to the ground. 
       FIGS. 1-4  illustrate injection molding system  1  of US 2018/0009146/Japanese patent publication No. 2018-001738/VN20160002505 and are being provided herein for information/description purposes only. 
     The injection molding system  1  includes an injection molding machine  2 , conveying machines  3 A and  3 B, and a control apparatus  4 . The injection molding system  1  manufactures a molded part while alternating a plurality of molds using the conveying machines  3 A and  3 B for the one injection molding machine  2 . Two molds,  100 A and  100 B are used. 
     The mold  100 A/ 100 B is a pair of a fixed mold  101  and a movable mold  102 , which is opened/closed in relation to the fixed mold  101 . The molded part is molded by injecting a molten resin into a cavity formed between the fixed mold  101  and the movable mold  102 . Clamping plates  101   a  and  102   a  are respectively fixed to the fixed mold  101  and the movable mold  102 . The clamping plates  101   a  and  102   a  are used to lock the mold  100 A/ 100 B to a molding operation position  11  (mold clamping position) of the injection molding machine. 
     For the mold  100 A/ 100 B, a self-closing unit  103  is provided for maintaining a closed state between the fixed mold  101  and the movable mold  102 . The self-closing unit  103  enables preventing the mold  100 A/ 100 B from opening after unloading the mold  100 A/ 100 B from the injection molding machine  2 . The self-closing unit  103  maintains the mold  100 A/ 100 B in a closed state using a magnetic force. The self-closing unit  103  located at a plurality of locations along opposing surfaces of the fixed mold  101  and the movable mold  102 . The self-closing unit  103  is a combination of an element on the side of the fixed mold  101  and an element on the side of the movable mold  102 . For the self-closing unit  103 , typically two or more pair are installed for one of the molds  100 A and  100 B. 
     A conveying machine  3 A loads and unloads the mold  100 A onto/from the molding operation position  11  of the injection molding machine  2 . A conveying machine  3 B loads and unloads the mold  100 B onto/from the molding operation position  11 . The conveying machine  3 A, the injection molding machine  2 , and the conveying machine  3 B are arranged to be lined up in this order in the X-axis direction. In other words, the conveying machine  3 A and the conveying machine  3 B are arranged laterally with respect to the injection molding machine  2  to sandwich the injection molding machine  2  in the X-axis direction. The conveying machines  3 A and  3 B are arranged to face each other, and the conveying machine  3 A is arranged on one side laterally of the injection molding machine  2 , and the conveying machine  3 B is arranged on the other side respectively adjacent. The molding operation position  11  is positioned between the conveying machine  3 A and the conveying machine  3 B. The conveying machines  3 A and  3 B respectively include a frame  30 , a conveyance unit  31 , a plurality of rollers  32 , and a plurality of rollers  33 . 
     The frame  30  is a skeleton of the conveying machine  3 A and  3 B, and supports the conveyance unit  31 , and the pluralities of rollers  32  and  33 . The conveyance unit  31  is an apparatus that moves the mold  100 A/ 100 B back and forth in the X-axis direction, and that removes and inserts the mold  100 A/ 100 B in relation to the molding operation position  11 . 
     The conveyance unit  31  is an electrically driven cylinder with a motor as a driving source, and includes a rod that moves forward/backward in relation to the cylinder. The cylinder is fixed to the frame  30 , and the fixed mold  101  is fixed to the edge portion of the rod. For the conveyance unit  31  both a fluid actuator and an electric actuator can be used, where the electric actuator can provide better precision of control of the position or the speed when conveying the mold  100 A/ 100 B. The fluid actuator can be an oil hydraulic cylinder, or an air cylinder, for example. The electric actuator can, in addition to an electrically driven cylinder, be a rack-and-pinion mechanism with a motor as the driving source, a ball screw mechanism with a motor as the driving source, or the like. 
     The conveyance unit  31  is arranged independently for each of the conveying machines  3 A and  3 B. However, a common support member that supports the molds  100 A and  100 B can be used, and a single common conveyance unit  31  can be arranged for this support member. A case where the conveyance unit  31  is arranged independently for each of the conveying machines  3 A and  3 B enables handling cases where a movement strokes differ between the mold  100 A and the mold  100 B when conveying. For example, a case in which molds cannot be conveyed simultaneously since the widths of the molds (the width in the X direction) differ or the thickness of the molds (the width in the Y direction) differ. 
     The plurality rollers  32  configure a row of rollers arranged in the X-axis direction, where two rows are configured separated in the Y-axis direction. The plurality of rollers  32  rotate around the axis of revolution in the Z-axis direction, and guide movement in the X-axis direction of the mold  100 A/ 100 B contacting the side surfaces of the mold  100 A/ 100 B (the side surfaces of the clamping plates  101   a  and  102   a ) and supporting the mold  100 A/ 100 B from the side. The plurality rollers  33  configure a row of rollers arranged in the X-axis direction, where two rows are configured separated in the Y-axis direction. The plurality of rollers  33  rotate around the axis of revolution in the Y direction, and cause movement in the X direction of the mold  100 A/ 100 B to be smooth, supporting the bottom surfaces of the mold  100 A/ 100 B (the bottom surfaces of the clamping plates  101   a  and  102   a ) and supporting the mold  100 A/ 100 B from below. 
     The control apparatus  4  includes a controller  41  for controlling the injection molding machine  2 , a controller  42 A for controlling the conveying machine  3 A, and a controller  42 B for controlling the conveying machine  3 B. Each of the controllers  41 ,  42 A and  42 B includes, for example, a processor such as a CPU, a RAM, a ROM, a storage device such as a hard disk, and interfaces connected to sensors or actuators (not illustrated). The processor executes programs stored in the storage device. An example of a program (control) that the controller  41  executes is described below. The controller  41  is communicably connected with the controllers  42 A and  42 B, and provides instructions related to the conveyance of the mold  100 A/ 100 B to the controllers  42 A and  42 B. The controllers  42 A and  42 B, if loading and unloading of the mold  100 A/ 100 B terminates, transmit a signal for operation completion to the controller  41 . In addition, the controllers  42 A and  42 B transmit an emergency stop signal at a time of an abnormal occurrence to the controller  41 . 
     A controller is arranged for each of the injection molding machine  2 , the conveying machine  3 A, and the conveying machine  3 B, but one controller can control all three machines. The conveying machine  3 A and the conveying machine  3 B can be controlled by a single controller for more reliable and collaborative operation. 
       FIG. 2  illustrates a side view of the injection molding machine  2 .  FIG. 3  illustrates an end view of a fixed platen  61 , and a figure viewing from the arrow direction of the I-I line in  FIG. 2 .  FIG. 4  illustrates a partial perspective view for describing the configuration of a periphery of the molding operation position  11 . 
     With reference to  FIG. 1  and  FIG. 2 , the injection molding machine  2  includes an injecting apparatus  5 , a clamping apparatus  6 , and a take-out robot  7  for ejecting a molded part. The injecting apparatus  5  and the clamping apparatus  6  are arranged on a frame  10  in the Y-axis direction. 
     The injecting apparatus  5  includes an injection cylinder  51  that is arranged to extend in the Y-axis direction. The injection cylinder  51  includes a heating device (not illustrated) such as a band heater, and melts a resin introduced from a hopper  53 . A screw  51   a  is integrated into the injection cylinder  51 , and by rotation of the screw  51   a,  plasticizing and measuring the resin introduced into the injection cylinder  51  are performed, and by movement in the axial direction (Y-axis direction) of the screw  51   a,  it is possible to inject a molten resin from an injection nozzle  52 . 
     In  FIG. 2 , an example of a shut-off nozzle as the nozzle  52  is illustrated. For an opening/closing mechanism  56  of  FIG. 2 , a pin  56   a  for opening/closing the discharge port  52   a  is arranged. The pin  56   a  is connected with an actuator (a cylinder)  56   c  via a link  56   b,  and by the operation of the actuator  56   c  the discharge port  52   a  is opened and closed. 
     The injection cylinder  51  is supported by a driving unit  54 . In the driving unit  54 , a motor for plasticizing and measuring the resin by rotationally drive the screw  51   a,  and a motor for driving the screw  51   a  to move forward/backward in the axial direction are arranged. The driving unit  54  can move forward/backward in the Y-axis direction along a rail  12  on the frame  10 , and in the driving unit  54 , an actuator (for example, an electrically driven cylinder)  55  for causing the injecting apparatus  5  to move forward/backward in the Y-axis direction is arranged. 
     The clamping apparatus  6  performs a clamping and opening and closing of the molds  100 A/ 100 B. In the clamping apparatus  6 , the following are arranged in order in the Y-axis direction: the fixed platen  61 , a movable platen  62 , and a movable platen  63 . Through platens  61  to  63 , a plurality of tie-bars  64  pass. Each of the tie-bars  64  is an axis that extends in the Y-axis direction, one end of which is fixed to the fixed platen  61 . Each of the tie-bars  64  is inserted into a respective through hole formed in the movable platen  62 . The other end of each of the tie-bars  64  is fixed to the movable platen  63  through an adjusting mechanism  67 . The movable platens  62  and  63  can move in the Y-axis direction along a rail  13  on the frame  10 , and the fixed platen  61  is fixed to the frame  10 . 
     A toggle mechanism  65  is arranged between the movable platen  62  and the movable platen  63 . The toggle mechanism  65  causes the movable platen  62  to move forward/backward in the Y-axis direction in relation to the movable platen  63  (in other words, in relation to the fixed platen  61 ). The toggle mechanism  65  includes links  65   a  to  65   c.  The link  65   a  is connected rotatably to the movable platen  62 . The link  65   b  is pivotably connected to the movable platen  63 . The link  65   a  and the link  65   b  are pivotably connected to each other. The link  65   c  and the link  65   b  are pivotably connected to each other. The link  65   c  is pivotably connected to an arm  66   c.    
     The arm  66   c  is fixed on a ball nut  66   b.  The ball nut  66   b  engages a ball screw shaft  66   a  that extends in the Y-axis direction, and moves forward/backward in the Y-axis direction by rotation of the ball screw shaft  66   a.  The ball screw shaft  66   a  is supported such that it is free to rotate by the movable platen  63 , and a motor  66  is supported by the movable platen  63 . The motor  66  rotationally drives the ball screw shaft  66   a  while the rotation amount of the motor  66  is detected. Driving the motor  66  while detecting the rotation amount of the motor  66  enables clamping, opening, and closing of the mold  100 A/ 100 B. 
     The injection molding machine  2  includes sensors  68  for measuring a clamping force, where each sensor  68  is, for example, a strain gauge provided on the tie-bar  64 , and calculates a clamping force by detecting a distortion of the tie-bar  64 . 
     The adjusting mechanism  67  includes nuts  67   b  supported to freely rotate on the movable platen  63 , motors  67   a  as driving sources, and transfer mechanisms for transferring the driving force of the motors  67   a  to the nuts  67   b.  Each of the tie-bars  64  passes through a hole formed in the movable platen  63 , and engages with the nut  67   b.  By causing the nuts  67   b  to rotate, the engagement positions in the Y-axis direction between the nuts  67   b  and the tie-bars  64  change. That is, the position at which the movable platen  63  is fixed in relation to the tie-bar  64  changes. With this, it is possible to cause a space between the movable platen  63  and the fixed platen  61  to change, and thereby it is possible to adjust a clamping force or the like. 
     The molding operation position  11  is a region between the fixed platen  61  and the movable platen  62 . 
     The mold  100 A/ 100 B introduced into the molding operation position  11  are sandwiched between the fixed platen  61  and the movable platen  62  and thereby clamped. Opening and closing in based on movement of the movable mold  102  by movement of the movable platen  62  is performed. 
       FIG. 3  illustrates an opening portion  61   a  in a central portion of the fixed platen  61  through which the nozzle  52  moves forward/backward. To the surface on the side of the movable platen  62  (called an inner surface) of the fixed platen  61  a plurality of rollers BR are supported such that they are free to rotate. The plurality of rollers BR rotate around the axis of revolution in the Y-axis direction, and cause movement in the X-axis direction of the mold  100 A/ 100 B to be smooth, supporting the bottom surfaces (the bottom surface of the clamping plate  101   a ) of the mold  100 A/ 100 B and supporting the mold  100 A/ 100 B from below. On both sides in the X-axis direction of the fixed platen  61 , a roller supporting body  620  is fixed, and the plurality of rollers BR are supported by the roller supporting body  620 . 
     On the inner surface of the fixed platen  61 , grooves  61   b  that extend in the X-axis direction are formed. 
     The grooves  61   b  are formed in two rows separated vertically. On each of the grooves  61   b  a roller unit  640  is arranged. For the roller unit  640 , a plurality of rollers SR are supported such that they are free to rotate. The plurality of rollers SR rotate around the axis of revolution in the Z-axis direction, and guide movement in the X-axis direction of the mold  100 A/ 100 B contacting the outer surfaces of the mold  100 A/ 100 B (the outer surface of the clamping plate  101   a ) and supporting the mold  100 A/ 100 B from the side. As illustrated in the cross sectional view of the line II-II, while the roller unit  640 , by a bias of a spring  641 , is positioned at a position at which the roller SR protrudes from the groove  61   b,  at a time of clamping it is retracted in the groove  61   b,  and positioned at a position at which the roller SR does not protrude from the groove  61   b.  The roller unit  640  can prevent the inner surfaces of the mold  100 A/ 100 B and the fixed platen  61  from contacting and damaging the inner surfaces at a time of alternating the mold  100 A/ 100 B, and the roller unit  640  does not impede the inner surface of the fixed platen  61  and the mold  100 A/ 100 B being closed at a time of clamping. 
     On both sides in the X-axis direction of the fixed platen  61 , a roller supporting body  630  is fixed, and a plurality of rollers SR are supported by the roller supporting body  630 . 
     On the fixed platen  61 , a plurality of fixing mechanisms (clamps)  610  are arranged for fixing the fixed mold  101  to the fixed platen  61 . Each fixing mechanism  610  includes an engaging portion  610   a  that engages with the clamping plate  101   a,  and a built-in actuator (not illustrated) that moves the engaging portion  610   a  between an engagement position and an engagement release position. 
     Note that for the movable platen  62 , similarly to the fixed platen  61 , a plurality of rollers BR, the roller supporting bodies  620  and  630 , the roller unit  640 , and the fixing mechanism  610  for fixing the movable mold  102  are arranged. 
     As illustrated in  FIG. 4 , the periphery of the clamping apparatus  6  is surrounded by a cover (exterior covering plate)  60  for safety, but openings  60   a  through which the mold  100 A/ 100 B pass are formed on the sides of the molding operation position  11  for alternating the mold  100 A/ 100 B. Each opening  60   a  is typically continuously open, enabling free removal and insertion of the mold  100 A/ 100 B from and to the molding operation position  11 . 
     Returning to  FIG. 2 , the take-out robot  7  will now be described. The take-out robot  7  includes a rail  71  that extends in the X-axis direction, and a movable rail  72  that can move in the X-axis direction on the rail  71 . The movable rail  72  is arranged to extend in the Y-axis direction, and a slider  73  is arranged on the movable rail  72 . The slider  73  moves in the Y-axis direction guided by the movable rail  72 , and moves up and down an elevating shaft  73   a  in the Z-axis direction. On a lower end of the elevating shaft  73   a,  a vacuum head  74  is arranged, and on the vacuum head  74 , a chuck plate  75  specialized to a molded part is mounted. 
     The take-out robot  7 , after opening, moves the vacuum head  74  between the fixed mold  101  and the movable mold  102  as illustrated by broken lines in  FIG. 2  by the rail  71 , the movable rail  7 , and the slider  73 , sticks to the molded part, and conveys it outside the mold  100 A/ 100 B. 
       FIG. 6  is being provided herein for information/description purposes only. EX 1  of  FIG. 6  indicates an example of the chuck plate  75 . The chuck plate  75  includes a holding portion  75 A and a holding portion  75 B. The vacuum head  74  causes the chuck plate  75  to rotate around an axis  74   a,  and causes the chuck plate  75  to be displaced so that the positions of the holding portion  75 A and the holding portion  75 B change. This provides for switching the holding portion facing the molded part, handling different molded parts in a short time without replacing the chuck plate  75 . EX 2  of  FIG. 6  illustrates another example of the chuck plate  75 . The chuck plate  75  includes a holding portion  75 A and the holding portion  75 B. The vacuum head  74  includes a rail  74   b  and a slider  74   c  that moves along the rail  74   b,  and the chuck plate  75  is arranged on the slider  74   c.  Moving the slider  74   c  results in the chuck plate  75  being displaced to change the positions of the holding portion  75 A and the holding portion  75 B. This provides for switching the holding portion facing the molded part handling different molded parts in a short time without replacing the chuck plate  75 . 
       FIG. 5  is a flowchart illustrating an example of a control method of the injection molding system  1  executed by the controller  41 . 
     In the following example, a case in which a molding operation is performed while alternating the molds  100 A and  100 B in the following manner: molding using the mold  100 A→molding using the mold  100 B→molding using the mold  100 A, etc., is envisioned. However, a molded part A molded in the mold  100 A is placed in the mold  100 B when the mold  100 B is open. Then, a resin is injected in the mold  100 B containing the molded part A, and a molded part B united with the molded part A is manufactured. 
     At the beginning of this processing flow, the mold  100 B with resin injected has been unloaded from the injection molding machine  2  to the conveyance machine  3 B. The following description describes the processes that follow this step. In step S 1  of  FIG. 5 , the cooled mold  100 A is loaded into the injection molding machine  2 . The mold A includes the molded part A that was made from the resin injected in the previous cycle and then hardened in the cooling process. In step S 2 , the motor  66  is driven to move the movable platen  62  away from the stationary platen  61 . The stationary mold  101  is fixed to the stationary platen  61  by the fixing mechanisms  610 , and the movable mold  102  is fixed to the movable platen  62  by the fixing mechanisms  610 . Thus, the movable mold  102  separates from the stationary mold  101  and the mold  100 A is opened. 
     In step S 3 , the take-out robot  7  drives the holding portion  75 A to remove the molded part A, remaining on the side of the movable mold  102  of the mold  100 A. The molded part A that is removed continues to be held by the holding portion  75 A until the process of step S 12 . 
     In step S 4 , the clamping device  6  drives the motor  66  to drive the toggle mechanism  65  to perform clamping of the mold  100 A with the stationary platen  61  and the movable platen  62 . 
     In step S 5 , the preparation for injection to the mold  100  A is performed by the injecting machine  5 . The injecting machine  5  drives the actuator  55  to move the injection machine  5  to move the nozzle  52  such that it contacts the mold  100 A. 
     In step S 6 , injection and dwelling of molten resin is performed. The injection machine  5  is driven to fill molten resin into a cavity in the mold  100 A from the nozzle  52 , and to press the resin into the mold  100 A at a high pressure in order to compensate for a volume decrease due to resin solidifying. The actual clamping force is measured by the sensor  68  during the processing of step S 6 . During molding, the mold  100 A thermally expands due to the temperature of the mold  100 A gradually rising. There are cases where a difference arises in the initial clamping force and the clamping force after a period of time has passed. Accordingly, it is possible to correct the clamping force at the time of the next clamping based on a result of measurement by the sensors  68 . 
     The adjustment of the clamping force is performed by an adjustment of the position of the movable platen  63  in relation to the tie-bar  64  by driving the motor  67 . This enables enhance precision of the clamping force by adjusting the clamping force by correcting the initial value of the position of the movable platen  63  in relation to the tie-bars  64  based on the result of measurement by the sensors  68 . The adjustment of the position of the movable platen  63  in relation to the tie-bars  64  can be performed at any timing (for example, step S 6 , step S 7 , steps S 13 -S 15  in the flowchart of  FIG. 5 ). 
     In step S 7 , processing related to the clamping device  6  is performed. First, locking of the mold  100 A by the fixation mechanisms  610  is released. The motor  66  is driven to drive the toggle mechanism  65 . This results in removal of the clamping force, the movable platen  62  separates slightly in relation to the stationary platen  61 , and a space in which it is possible to alternate the molds  100 A and  100 B is formed. 
     In step S 8 , the mold  100 A is unloaded or ejected from the molding operation position  11  to the conveying machine  3 A. After the mold  100 A is ejected from the molding operation position  11 , the mold  100 A is cooled to the appropriate temperature during for predetermined time period. A mold typically includes a channel running inside the mold, a temperature controller is connected, via a hose, to the interface of the channel formed on a surface of the mold, while the mold is prepared for injection molding. The fluid at a certain temperature flows from the temperature controller inside the mold, to keep the mold at a certain temperature. During the injection molding processes, including the cooling process, fluid is usually always running inside the mold. 
     Typically, after step S 8 , the mold  100 A is still heated up from the melted resin injected into the mold  100 A. In the cooling process by the fluid from the temperature controller, the temperature is dropped to a predefined temperature, for example 60 degrees Celsius. The cooling process continues until a predetermined time period passes from the start of the cooling process. 
     In some injection molding processes like heat and cool molding, the cooling process includes a dedicated temperature controller to cool down a mold to a certain temperature, which is different from a temperature at which a mold receives the melted resin from an injecting machine. 
     In step S 9 , the mold  100 B is loaded from the conveying machine  3 B to the molding operation position  11 . In step S 10 , the movable platen  62  is separated from the fixed platen  61  by driving the motor  66 . The stationary mold  101  is fixed to the stationary platen  61  by the fixing mechanisms  610 , and the movable mold  102  is fixed to the movable platen  62  by the fixing mechanisms  610 . Therefore the movable mold  102  separates from the stationary mold  101  and the mold  100 B is opened against the force of the self-closing unit  103 . In step S 11 , the molded part B, which is united with molded part A, remaining on the side of the movable mold  102  of the mold  100 B is removed by driving the take-out robot  7  and using the holding portion  75 B is conveyed outside the injection molding machine  2 . 
     In step S 12 , the molded part A being held by the holding portion  75 A is placed in the metal mold B. In step S 13 , clamping of the mold  100 B is performed. In step S 14 , preparation for injection to the mold  100 B is performed by driving the actuator  55  to move the injection machine  5 . This causes the nozzle  52  to contact the mold  100 B. 
     In step S 15 , injection and dwelling of molten resin is performed. In step S 16 , processing related to the clamping device  6  is performed, which is the same process as in step S 7 . In step S 17 , the mold  100 B is unloaded from the molding operation position  11  to the conveying machine  3 B. 
     As described above, in the present embodiment, cooling of the mold  100 A/ 100 B is performed on the conveying machines  3 A or  3 B outside the injection molding machine  2 . Also, during cooling of one of the molds  100 A or  100 B, each process of molded part ejection→clamping→injection/dwelling is performed by the injection molding machine  2  for the other of the mold  100 A or  100 B. Since opening and molded part ejection are performed by the injection molding machine  2 , the conveying machines  3 A and  3 B do not need to include a function for opening and a function for molded part ejection. 
     Accordingly, it is possible to manufacture the molded part B united with molded part A while alternating the multiple molds  100 A and  100 B by one injection molding machine  2  while avoiding cost increases to the injection molding system  1 . Because the injection molding system  2  molds a molded part B following the molding of a molded part A, it is not necessary to manufacture a large quantity of molded part A beforehand. Thus, it is possible to decrease the risk of storing excess inventory of molded part A. 
       FIG. 7  is an illustrative view of a chuck plate of another exemplary embodiment.  FIG. 7  illustrates the chuck plate  74   e  connected to the tip of the axis  74   d.  The chuck plate  74   e  includes several holding portions  75 A on one surface and several holding portions  75 B on another surface. It is possible to switch the holding portion facing the molded part by rotating the chuck plate  74   e  around an axis  74   d . The rotation angle is not limited to 180 degree. Any angle that enables the holding portion to properly catch and hold the molded part is applicable. 
     The take-out robot  7  can include a robotic hand that can hold both molded part A and molded part B. In the above-described embodiment, e the take-out robot  7  keeps holding the molded part after the take-out robot  7  has removed the molded part from the first mold until the take-out robot  7  places the molded part in the second mold. In another exemplary embodiment, the take-out robot  7  can place the molded part on a table (not illustrated) temporarily provided near the molding operation position  11 . 
     If it is necessary to sufficiently cool down the molded part A before it is placed in the mold  100 B, the molded part A can be cooled on the table while one or more cycles of changing the molds pass. In this case, it is better to enable putting the molded parts A on the table for longer than the number of cycles necessary to cool them. This enables using a molded part A that was molded one or more previous exchange cycles as the molded part to place in the mold  100 B. 
     A sensor (not illustrated) can be installed in the mold to enable detecting that the molded part A was placed in the mold  100 B. A pressure sensor or optical sensor can be used. An image of the placement condition can be captured using a camera installed in the vicinity of the molding operation position  11 , where the captured image is used to judge placement. The sensor for detecting that the molded part A is placed in the mold  100 B can be located in other positions in the injection molding machine  2  other than the mold  100 A/ 100 B and the take-out robot  7 . 
     In another exemplary embodiment, a table can be provided to adjust the holding orientation of the molded part A held by the take-out robot  7 . Repositioning of the molded part A can also occur on the table. A sensor (image sensor, etc.) (not illustrated) installed in the vicinity of the table or on the take-out robot  7  to can be used to change the hold to an accurate orientation to place the molded part in the mold  100 B. 
     In an exemplary embodiment of the injection molding system  1 , an inspection process is conducted to ensure that a molded part is considered to be acceptable A molded part is considered to be acceptable, for example, if there are no detected abnormalities, etc. either on the surface of the mold or within the internal structure of the mold. 
     The inspection process can include, for example, an image capturing device located in the injection molding machine  2  that captures an image of the external appearance the molded part. The molded part is checked with respect to the surface condition and the shape of the molded part based on the captured image. The molded part can also be checked with respect to the color of the molded part based on the captured image. 
     An image capturing device that captures an internal structure of the molded part using radiation, such as X-ray, can also be used for the checking process. In a case where the checking process for the molded part B is performed outside the injection molding machine  2 , the checking process for the molded part A performed in the injection molding machine  2  can be just the external appearance inspection. 
     In the inspection process, the molded part A is removed by the take-out robot  7 , one or more image capturing devices controlled by the control device  4  capture an image with the appearance of the molded part A in a state where the molded part A is held by the take-out robot  7 . The captured image is analyzed by the control device  4 , and a result indicating whether the molded part A is an accepted part is provided. In another embodiment, the captured image can be analyzed by components other than the control device  4 . 
     In another embodiment, the molded part A removed by the take-out robot  7  can be placed at a predetermined position outside the injection molding machine  2 , where the inspection process for the molded part A can be performed. In this case, the take-out robot  7  does not maintain a hold on the molded part A during a period from when the take-out robot  7  removes the molded part A from the mold  100 A to when the take-out robot  7  places the molded part A in the mold  100 B. 
     In the event that the molded part A is deemed not accepted, there are various options that can be followed. In one option, the mold  100 A is not moved from the molding operation position  11  in the injection molding machine  2 , and the injection molding using the mold  100 A is repeated. In a case where the mold  100 A has already been moved from the injection molding machine  2  before the inspection process is performed, the mold  100 A is moved to the injection molding machine  2  again, and the injection molding using the mold  100 A is repeated. The molded part A is then re-checked. If the molded part A is determined to be an accepted part, the molded part A is placed in the mold  100 B. If the molded part A is determined as the accepted part, the mold  100 A is moved from the injection molding machine  2  and the mold  100 B is moved in the injection molding machine  2  as usual. 
     In a second option, another accepted part is prepared outside the injection molding machine  2  in advance, while the prepared molded part A is held by the take-out robot  7 , and used instead of a non-accepted part. In this case, based on the determination indicating that the molded part A is a non-accepted part, the control device  4  controls the take-out robot  7  to release the non-accepted part so that the non-accepted part can be disposed of. The prepared molded part A is held by take-out robot  7  and placed in the mold  100 B. If the molded part A is determined to be an accepted part, the molded part A that was just removed by take-out robot  7  from the mold  100 A is placed in the mold  100 B as usual. 
     In a third option, the take-out robot  7  places the molded part A at a predetermined position outside the injection molding machine  2 . In this case, after placing the molded part A at the predetermined position, the take-out robot  7  holds another molded part A determined as an accepted part and places it in the mold  100 B. This flow is effective where a time required to check the molded part A is relatively long. 
     The process associated with each of the above-described options are pre-installed in the control device  4 . The injection molding machine  2  selects, based on, for example, a user&#39;s inputs, one of the processes. 
     In a case where the molded part A is not an accepted part, the molded part B including the molded part A is not an accepted part as well. The molded part A should be inspected to determine whether it is an accepted part before the molded part A is placed in the mold  100 B. 
     In the above-described second option, it is preferable to only produce some molded parts A in advance. That is, the mold  100 A is placed at the molding operation position  11  and the injection molding is performed until a predetermined number, for example  10 , of accepted parts A is produced. The injection molding machine  2  operates in a mode where the injection molding only uses the mold  100 A. In a case where the predetermined number of accepted parts A is produced, the injection molding machine  2  enters a mode where the injection molding alternately uses the mold  100 A and the mold  100 B. The mode where the injection molding uses only the mold  100 A can also be adopted in the above-described third option. 
     In the injection molding process after the molded part A is determined to be a non-accepted part in the above-described first option, and the injection molding process for producing the predetermined number of the molded parts A in advance, it is not necessary to cool the mold  100 A at a position other than the molding operation position  11 . In other words, it is not necessary to cool the mold  100 A by moving the mold  100 A out of the injection molding machine  2 . There is, however, a difference between a pressure applied to the mold where the mold is cooled on the conveying machines  3 A or  3 B and a pressure applied to the mold where the mold is cooled at the molding operation position  11  in the injection molding machine  2 . Thus, the quality of the mold can differ between these two situations. 
     In the above injection molding processes, the mold  100 A can be cooled where the mold  100 A is moved from the molding operation position  11 . The mold  100 A can also be cooled where the mold  100 A is at the molding operation position  11  and the platens  61 ,  62  can be separated from the mold  100 A. This makes the pressure applied to the mold  100 A similar to that where the mold  100 A is cooled on the conveying machines  3 A or  3 B. 
     According to an embodiment, multiple take-out robots  7  can be installed. For example, a robot A (not illustrated) is used to remove the molded part A from the mold  100 A and to place the molded part A in the mold  100 B. A robot B (not illustrated) can be used to remove the molded part B from the mold  100 B. In this case, because the robot A only has to be able to operate in the vicinity of the molding operation position  11 , it can be installed, for example, below the vicinity of the molding operation position  11 , and can have a smaller operating area than the robot B. In this configuration, it may be necessary for the robot B to be of a size enabling transfer of the removed molded part B outside the injection molding machine  2 . 
     While the above-described embodiments have referenced the use of two molds, the number of molds is not limited to two. The above-described embodiments enable alternating between multiple molds while performing injection molding. 
     While the above described-embodiments have described performing, clamping, injection/dwelling, opening, and ejection where the mold is at the molding operation position  11 , this is not seen to be limiting. All processes do not need to be performed at the molding operation position  11 . Some of the processes can be performed at a position different from the molding operation position  11 . For example, after a cooling process of a mold, the mold is conveyed to a predetermined position in the injection molding machine  2 , which is different from the molding operation position  11 . The molded part can be removed at the predetermined position. The mold can then be conveyed from the predetermined position to the molding operation position  11 . 
     While the above-described embodiments discussed that the cooling process is performed where the mold is on the conveying machines  3 A or  3 B and is external to the injection molding machine  2 , this is not seen to be limiting. The cooling process can be performed at a position where the mold does not contact the fixed platen  61  and the movable platen  62 . For example, the cooling process can be performed where a part of the mold is in the injection molding machine  2  and another part of the mold is outside the injection molding machine  2 . Where a configuration that a part of the conveying machine  3 A or  3 B is located in the injection molding machine  2  is used, the cooling process can be performed where a part of the mold is in the injection molding machine  2  and another part of the mold is on either the conveying machine  3 A or  3 B. 
     Definitions 
     In referring to the description, specific details are set forth in order to provide a thorough understanding of the examples disclosed. In other instances, well-known methods, procedures, components and circuits have not been described in detail as not to unnecessarily lengthen the present disclosure. 
     It should be understood that if an element or part is referred herein as being “on”, “against”, “connected to”, or “coupled to” another element or part, then it can be directly on, against, connected or coupled to the other element or part, or intervening elements or parts may be present. In contrast, if an element is referred to as being “directly on”, “directly connected to”, or “directly coupled to” another element or part, then there are no intervening elements or parts present. When used, term “and/or”, includes any and all combinations of one or more of the associated listed items, if so provided. 
     Spatially relative terms, such as “under” “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the various figures. It should be understood, however, that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, a relative spatial term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated  90  degrees or at other orientations) and the spatially relative descriptors used herein are to be interpreted accordingly. Similarly, the relative spatial terms “proximal” and “distal” may also be interchangeable, where applicable. 
     The term “about,” as used herein means, for example, within 10%, within 5%, or less. In some embodiments, the term “about” may mean within measurement error. 
     The terms first, second, third, etc. may be used herein to describe various elements, components, regions, parts and/or sections. It should be understood that these elements, components, regions, parts and/or sections should not be limited by these terms. These terms have been used only to distinguish one element, component, region, part, or section from another region, part, or section. Thus, a first element, component, region, part, or section discussed below could be termed a second element, component, region, part, or section without departing from the teachings herein. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “includes”, “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Specifically, these terms, when used in the present specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof not explicitly stated. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, if the range 10-15 is disclosed, then 11, 12, 13, and 14 are also disclosed. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure. 
     It will be appreciated that the methods and compositions of the instant disclosure can be incorporated in the form of a variety of embodiments, only a few of which are disclosed herein. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the disclosure to be practiced otherwise than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context. 
     Combinations of any exemplary embodiments disclosed above are also included as embodiments of the present disclosure. While the above-described exemplary embodiments discuss illustrative embodiments, these embodiments are not seen to be limiting.