Manufacturing device and manufacturing method for resin container

Abstract

To provide a manufacturing apparatus of a resin container and a manufacturing method thereof, capable of properly stretching blow molding a preform in a comparatively short time and stably manufacturing a resin container with excellent quality.SOLUTION: A manufacturing apparatus of a resin container for stretching a preform 10 by stretching the preform 10 arranged in a stretching blow molding mold 144 by using a stretching rod 145 and introducing blow air to the preform 10 to form a resin container, has: detection means 182 for detecting an actual position of the stretching rod 145 inserted in the preform 10; and supply control means 183 for controlling a supply state of blow air based on a detection result of the detection means 182.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to an apparatus and method for manufacturing a resin container (hollow container) to be filled with, for example, a beverage, etc., and more particularly to an apparatus and method for manufacturing a resin container in which an injection-molded preform is stretch-blow molded to form a resin container. [Background technology]

[0002] Conventionally, for example, as an apparatus for manufacturing a resin container (hollow container) made of a resin material such as polyethylene terephthalate (PET), there has been known one that includes a biaxial stretch blow molding apparatus that stretch blow molds a preform to produce a resin container.

[0003] A commonly known biaxial stretch blow molding apparatus forms a resin container by placing a preform formed by injection molding in a blow molding die, stretching the preform with a stretching rod and also stretching the preform with high-pressure blow air (see, for example, Patent Document 1).

[0004] In this way, when the preform is stretched by the stretch rod and the blow air, the operation of the stretch rod and the supply of the blow air are generally controlled independently. For example, the start of the supply of the blow air is controlled based on a waiting time starting from the blow start time, and is controlled independently of the operation of the stretch rod. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-231170 A Summary of the Invention [Problem to be solved by the invention]

[0006] Here, the resin container manufacturing apparatus includes an injection molding section that injection molds preforms and a stretch blow molding section that stretch blow molds the preforms, and the preforms transported from the injection molding section are made into resin containers (hollow containers) in the stretch blow molding section.

[0007] In such a resin container manufacturing apparatus, a preform is injection molded in the injection molding section while a preform is stretch blow molded in the stretch blow molding section to form a resin container. Therefore, it is necessary to set the stretch blow molding time according to the injection molding time of the preform.

[0008] In recent years, the injection molding time (including cooling time) of preforms has been dramatically shortened, and as a result, there is a demand for shorter molding cycle times (higher cycle times). In order to shorten the molding cycle time, it is necessary to shorten the stretch blow molding time in line with the shortening of the injection molding time.

[0009] However, if the stretch rod and the blow air supply are controlled independently, it is becoming difficult to respond to the shortening of the molding cycle time. In other words, it is becoming difficult to respond to the shortening of the molding cycle time of blow molding with the above-mentioned control based on the waiting time starting from the blow start time (timer control type).

[0010] In the timer control type, the time to start lowering the stretch rod and the time to start introducing the blow air are set, for example, in units of 10 milliseconds, starting from the blow start time. In addition, in the timer control type, due to the mechanical configuration, a slight error occurs between the set start time for lowering the stretch rod and introducing the blow air and the actual start time. This error has an effect on blow molding. For example, the quality (physical properties, appearance, etc.) of the container may decrease, molding defects such as bursting may occur frequently, and the moldability and productivity of the container in the blow molding may become unstable. In addition, the effect of the error on blow molding becomes greater as the blow molding time becomes shorter.

[0011] Furthermore, as the blow molding time becomes shorter, it becomes very difficult to properly coordinate the independent parameters of the time when the stretch rod begins to descend and the time when the blow air begins to be introduced.

[0012] In addition, shortening the molding cycle time (stretch blow molding time) may result in a deterioration in the quality of the resin container, and may also result in frequent molding defects such as bursting during blow molding, resulting in a deterioration in molding stability.

[0013] The present disclosure has been made in consideration of the above circumstances, and aims to provide a resin container manufacturing apparatus and manufacturing method that can appropriately stretch blow mold preforms in a relatively short time and consistently produce high-quality resin containers. [Means for solving the problem]

[0014] In order to achieve the above object, an apparatus for manufacturing a resin container according to one embodiment of the present invention comprises: A resin container manufacturing apparatus comprising: a preform disposed in a stretch blow molding die is stretched by a stretch rod; and blow air is introduced into the preform to stretch the preform into a resin container, a detection means for detecting an actual position of the stretch rod inserted into the preform; and a supply control means for controlling the supply state of the blow air based on the detection result of the detection means.

[0015] Here, it is preferable that the drive source of the stretch rod is a servo motor, and the detection means detects the actual position of the stretch rod based on the rotational position of the servo motor.

[0016] In addition, a method for producing a resin container according to one embodiment for achieving the above object includes the steps of: A method for manufacturing a resin container includes stretching a preform placed in a stretch blow molding mold with a stretch rod and introducing blow air into the preform to stretch the preform into a resin container, the method being characterized in that an actual position of the stretch rod inserted into the preform is detected and the supply state of the blow air is controlled based on the actual position of the stretch rod. Effect of the Invention

[0017] According to the present disclosure, even under conditions in which the stretch blow molding time is very short (high cycle conditions), the preform can be appropriately stretched, and good quality resin containers (hollow containers) can be stably produced. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a plan view illustrating an example of an overall configuration of a stretch blow molding apparatus according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating the configuration of the stretch blow molding section according to the present disclosure, and is a cross-sectional view of a stretch blow molding die. [Diagram 3] FIG. 3 is a diagram illustrating a molding procedure for a hollow container by a stretch blow molding unit according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a block diagram illustrating the configuration of a stretch blow molding unit according to an embodiment of the present disclosure. [Diagram 5] FIG. 5 is a diagram showing an example of a display on a display included in the control unit according to the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating the position of the stretch rod at each time. [Figure 7] FIG. 7 is a diagram illustrating a procedure for molding a hollow container by a stretch blow molding unit according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram showing an example of a display on a display included in a control unit according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] First embodiment Hereinafter, a first embodiment of the present disclosure will be described in detail with reference to FIGS. As illustrated in Figure 1, an injection stretch blow molding apparatus 100, which is a resin container manufacturing apparatus according to this embodiment, includes an injection molding section 110 that injection molds a bottomed cylindrical preform 10, a cooling section 120 that cools the preform 10 molded in the injection molding section 110, a heating section (heating device) 130 that heats the preform 10, and a stretch blow molding section 140 that stretch blow molds the preform 10 heated by the heating section 130 to form a hollow container 20 (see Figure 3).

[0020] This injection stretch blow molding apparatus 100 has an injection molding section 110 and a stretch blow molding section 140 connected in-line, but is a so-called 1.5 stage type apparatus in which the number of simultaneous injection molded pieces does not match the number of simultaneous blow molded pieces.

[0021] The injection stretch blow molding apparatus 100 also includes a conveying section 150 including a loop-shaped conveying line (conveying path) 151 that circulates from the cooling section 120 to the heating section 130 and the stretch blow molding section 140. The conveying section 150 conveys the preforms 10 along the conveying line 151 from the cooling section 120 to the heating section 130, and also conveys the preforms 10 heated in the heating section 130 toward the stretch blow molding section 140. The conveying section 150 further includes a gripping mechanism conveying section 155 that grips the preforms 10 conveyed along the conveying line 151 and carries them into the stretch blow molding section 140.

[0022] The gripping mechanism transport section 155 transports the preform 10 into the stretch blow molding section 140, and also grips and transports intermediate molded products within the stretch blow molding section 140 as described below, and also grips the hollow container 20, which is the final molded product, and transports it from the stretch blow molding section 140 to the removal position.

[0023] The injection stretch blow molding apparatus 100 according to the present disclosure is characterized by the configuration of the stretch blow molding section (stretch blow molding apparatus) 140. Note that other configurations such as the injection molding section 110, the cooling section 120, and the heating section 130 are well known, and therefore will be described briefly here.

[0024] The injection molding section 110 is equipped with a mold clamping mechanism (mold clamping device) 111, and although not shown, a core mold arranged above and a cavity mold arranged below are clamped by this mold clamping mechanism 111. In the injection molding section 110, a resin material (raw material) is filled by an injection device into an injection space defined by the core mold and the cavity mold, whereby a plurality of preforms 10 are injection molded.

[0025] Incidentally, this injection molding section 110 is configured so as to be able to mold N pieces (N is an integer of 2 or more) of preforms 10 at a time. Specifically, the injection molding section 110 is configured so as to be able to mold a maximum of 24 pieces (3 rows × 8 pieces) of preforms 10 at the same time, and in this embodiment, it is set so as to mold 12 pieces (3 rows × 4 pieces) of preforms 10 at a time.

[0026] The cooling section 120 forcibly cools the preforms 10. The preforms 10 injection molded in the injection molding section 110 are transported from the injection molding section 110 to the cooling section 120 by a transport device (not shown), and are forcibly cooled in the cooling section 120. Each preform 10 cooled to a predetermined temperature in the cooling section 120 is sent to a transport line 151 constituting the transport section 150, and is transported continuously along the transport line 151.

[0027] Each preform 10 is molded in the injection molding section 110 in an upright state with its neck facing upward, and is transported in this state from the injection molding section 110 to the cooling section 120. The cooling section 120 has an inversion mechanism (not shown) that inverts the preforms 10 transported in this upright state into an inverted state with its neck facing downward. Each preform 10 is inverted by the inversion mechanism into an inverted state while being cooled in the cooling section 120, and is held in the inverted state on the transport jig 152.

[0028] As described above, in this embodiment, twelve preforms 10 are formed in the injection molding section 110, and therefore each preform 10 is held by every other conveying jig 152 that is conveyed in succession.

[0029] The conveying line 151 is configured such that a plurality of conveying jigs 152 are continuously conveyed in sequence by the driving force of a sprocket 153 or the like. The conveying jigs 152 are arranged in a plurality of rows below the cooling section 120, and the conveying jigs 152 holding the preforms 10 are conveyed out to the conveying line 151 in sequence. Thereafter, the preforms 10 held by the conveying jigs 152 are conveyed along the conveying line 151 and conveyed into the heating section (heating device) 130.

[0030] In the heating section 130, the preform 10 held by the transport jig 152 is heated to an appropriate temperature for stretching while being moved along the transport line 151. The transport section 150 is configured so that the transport jig 152 moves on the transport line 151 while rotating on its axis. That is, in the heating section 130, the preform 10 is heated while rotating on its axis. As a result, in the heating section 130, the preform 10 is heated to a substantially uniform temperature over its entire circumference.

[0031] After the preforms 10 are heated by the heating section 130, the preforms 10 are further transported along the transport line 151 and carried into the stretch blow molding section 140. More specifically, the preforms 10 are transported along the transport line 151 to an inversion section 156 equipped with an inversion mechanism (not shown). Each preform 10 continuously transported along the transport line 151 is inverted in units of a predetermined number in this inversion section 156 to an upright state. Then, each upright preform 10 is gripped by the gripping mechanism transport section 155 described above and transported to the stretch blow molding section 140.

[0032] Then, a predetermined number of preforms 10 gripped by the gripping mechanism transport unit 155 in the inversion unit 156 are carried into the blow cavity mold 141. Note that the gripping mechanism transport unit 155 appropriately adjusts the intervals between each preform 10 while sliding each preform 10.

[0033] The gripping mechanism transport section 155 is only required to grip the neck portion of the preform 10 and move the preform 10 in this state to the stretch blow molding section 140, and the configuration thereof is not particularly limited.

[0034] 2, the stretch blow molding section 140 includes a plurality of stretch blow molding dies 144 each having a blow cavity die 141 consisting of a pair of split dies, a bottom die 142, and a blow core die (blow nozzle die) 143. Each blow cavity die 141 is formed with a plurality of (for example, two) cavities 141a for molding the preform 10 into the hollow container 20. The stretch blow molding section 140 also includes a stretch rod 145 that is inserted into the preform 10 to stretch the preform 10 in the axial direction.

[0035] The multiple blow cavity molds 141 included in the stretch blow molding section 140 are arranged adjacent to each other, and the multiple blow cavity molds 141 are configured to move integrally to be clamped. As illustrated in Fig. 1, in this embodiment, two blow cavity molds (one of the split molds) 141 are fixed to a blow mold fixing plate 146, and a mold clamping device (mold clamping mechanism) 147 is connected to this blow mold fixing plate 146. That is, by moving the blow mold fixing plate 146 by the mold clamping device 147, each of the two blow cavity molds 141 is clamped or opened simultaneously.

[0036] In the stretch blow molding section 140, each preform 10 placed in the cavity 141a of the blow cavity mold 141 is stretch blow molded to form a hollow container 20 as a final molded product.

[0037] Specifically, as illustrated in Fig. 3, the stretch rod 145 is moved (lowered) to press the bottom of the preform 10 with the stretch rod, and blow air (primary air) is introduced into the preform 10, thereby stretching the preform 10 in the vertical and horizontal directions. That is, the preform 10 is expanded to a predetermined size.

[0038] More specifically, as illustrated in FIG. 3(a), first, the stretch rod 145 is moved (lowered) to a preset first position P1, and the preform 10 is stretched in the vertical axis direction by the stretch rod 145. Next, when the stretch rod 145 reaches the preset first position P1, low-pressure blow air (primary air) is introduced into the preform 10, and the preform 10 is stretched in the vertical axis direction and the horizontal axis direction (FIG. 3(b)). In other words, the first position P1 is a reference position for starting to introduce the primary air into the preform 10. Note that the movement (lowering) of the stretch rod 145 continues even during the introduction of the primary air. The pressure of the primary air is set to, for example, 0.3 MPa to 1.5 MPa.

[0039] After that, as shown in FIG. 3(c), when the stretch rod 145 moves (descends) to a preset second position P2 (lower than the first position P1), the pressure of the blow air introduced into the preform 10 is changed. That is, the blow air introduced into the preform 10 is switched from the primary air to secondary air having a higher pressure than the primary air. That is, the second position P2 is a reference position for starting to introduce the secondary air into the preform 10. By switching from the primary air to the secondary air, the preform 10 is further stretched in the vertical and horizontal directions. At the same time, the stretch rod 145 is moved downward from the second position P2 to further stretch the preform 10 in the vertical direction, and the stretch rod 145 comes to rest at a third position P3, which is a preset final lowering position (stretch completion position). This forms the hollow container 20, which is the final molded product (FIG. 3(d)). The secondary air is set to a pressure of, for example, 2.0 MPa to 3.5 MPa.

[0040] The hollow container 20 molded in the stretch blow molding section 140 (stretch blow molding die 144) is transported by the gripping mechanism transport section 155 to a removal position Pa outside the stretch blow molding section 140 at the same timing as the next preform 10 is transported after the internal blow air has been exhausted. Then, the hollow container 20 is removed from the apparatus at the removal position Pa (see FIG. 1).

[0041] Incidentally, in the stretch blow molding section 140, N preforms 10 formed at one time in the injection molding section 110 are divided into n (n is an integer of 2 or more) batches, and M (N / n: M is a natural number) hollow containers 20 are formed at one time. In this embodiment, 12 preforms 10 formed at one time in the injection molding section 110 are divided into three batches, and four preforms 10 are stretch blow molded at one time to form hollow containers 20.

[0042] In this way, in the injection stretch blow molding apparatus 100, while one injection molding is performed in the injection molding section 110, three stretch blow moldings are performed in the stretch blow molding section 140, so the time available for one stretch blow molding is very short. For this reason, the movement of the stretch rod 145 and the supply of blow air in the stretch blow molding need to be controlled with high precision.

[0043] Therefore, in the injection stretch blow molding apparatus 100, the actual position of the stretch rod 145 is detected, and based on the detected actual position of the stretch rod 145, the start and stop of the introduction of blow air (primary air and secondary air) into the preform 10 is controlled. In other words, the control of the introduction of blow air into the preform 10, which was conventionally a timer control type based on the blow start time, is now a position control type based on the actual position of the stretch rod 145.

[0044] Here, the stretch blow molding section 140 includes a supply section 160 that supplies blow air to the blow core mold 143 (preform 10), a drive section 170 that drives the stretch rod 145, and a control section 180 that controls the supply section 160 and the drive section 170, as illustrated in the block diagram of Figure 4.

[0045] Although not shown, the supply unit 160 includes an air source and an air tank, as well as a supply system that supplies blow air from the air tank to the blow core mold 143 and an exhaust system that exhausts the blow air from the blow core mold 143. The drive unit 170 includes an electric drive source for moving (raising and lowering) the stretch rod 145. In this embodiment, the drive unit 170 includes a servo motor (electric motor) as a drive source.

[0046] The control unit 180 controls the operation of various devices equipped in the injection stretch blow molding apparatus 100, including the supply unit 160 and the drive unit 170. The control unit 180 is composed of, for example, an input / output device, a memory device (ROM, RAM, etc.), a central processing unit (CPU), a timer counter, etc.

[0047] Specifically, the control unit 180 includes a drive control means 181, a detection means 182, and a supply control means 183. The drive control means 181 controls the movement (lifting and lowering) of the stretch rod 145 by the servo motor of the drive unit 170. The drive control means 181 appropriately controls the start and stop and moving speed of the movement of the stretch rod 145 based on conditions set by an operator, for example.

[0048] The detection means 182 detects the actual position of the stretch rod 145 based on the rotational position (encoder output value) of the servo motor 171 provided in the drive unit 170. The method of detecting the actual position of the stretch rod 145 by the detection means 182 is not particularly limited.

[0049] The supply control means 183 controls the supply state of the blow air based on the detection result of the detection means 182. Specifically, the supply control means 183 controls the supply unit 160 based on the actual position of the stretch rod 145 detected by the detection means 182 to appropriately control the start and stop of the supply of blow air to the blow core mold 143, that is, the start and stop of the introduction of blow air (primary air and secondary air) into the preform 10. Therefore, the supply control means 183 can switch the blow air introduced into the preform 10 from primary air to secondary air based on the detection result of the detection means 182. In this embodiment, when the detection means 182 detects that the actual position of the stretch rod 145 is at the second position P2, the supply control means 183 controls the supply unit 160 to switch the blow air introduced into the preform 10 from primary air to secondary air.

[0050] In this embodiment, blow air (primary air and secondary air) is introduced into the preform 10 as appropriate when the stretch rod 145 reaches two arbitrarily set lowering positions (first position P1, second position P2). This allows the introduction of blow air according to the length and elongation state of the preform 10, and also makes it possible to handle high-cycle container molding. In other words, it also becomes possible to manufacture hollow containers 20, which were previously difficult to mold under high-cycle conditions. For example, it becomes possible to simultaneously manufacture a large number of thin-walled containers weighing 10 g or less under blow molding time conditions of 0.6 seconds.

[0051] The control unit 180 also includes a relatively large display (display means) 190 that displays on a screen setting information for setting the control conditions of various devices to be controlled, and also includes a display control means 184 that controls the display state of the screen of this display 190.

[0052] 5, the display 190 is provided with a main display section 191 that can set and display various information (control conditions, setting values, etc.) as necessary, and a sub-display section 192 that constantly displays specific information, etc. In this embodiment, the central area of ​​the display 190 functions as the main display section 191, and a header section 193 above the main display section 191 and a footer section 194 below the main display section 191 function as the sub-display section 192.

[0053] The display 190 is configured, for example, with a touch panel or the like, and also functions as an input means for an operator to input various control conditions (operation conditions of various devices and control conditions of various stations).

[0054] The display control means 184 displays information for setting control conditions as necessary on the main display section 191 of the display 190. For example, in the case of stretch blow molding, the display control means 184 displays a screen on which the actual position of the stretch rod 145 and the supply state of blow air including primary air and secondary air can be set in association with each other.

[0055] When controlling the supply unit 160 by position-controlled blow air supply control, the operator inputs various control conditions (set values) into the display 190 functioning as a touch panel. For example, in the main display unit 191, the operator inputs the blow molding time ("Blow time"), the blow air exhaust time ("Decomp. time"), etc., and also inputs the first position value (P1), the second position value (P2), and the third position value (P3) as the actual positions of the stretch rod 145 into the primary blow start position ("Pri."), the secondary blow start position ("Sec."), and the stretch completion position (not shown), respectively. By performing this input operation, the operator can set the timing at which the primary air introduced into the preform 10 in the primary blow (Pri.) and the secondary air introduced into the preform 10 in the secondary blow (Sec.) are supplied by the supply unit 160. The blow air supply timing can be set for each cavity 141a. In addition, the main display unit 191 can also display the time (actual measurement value) required for the stretch rod 145 to reach each of the first position P1, the second position P2, and the third position P3.

[0056] In this manner, in the injection stretch blow molding apparatus 100 according to this embodiment, the operator can appropriately set the conditions for position-controlled blow air supply control on a single screen.

[0057] Furthermore, the injection stretch blow molding apparatus 100 is configured to be able to switch between position-controlled blow air supply control and timer-controlled blow air supply control, allowing the operator to select a stretch blow molding control method appropriate for the hollow container 20 to be molded, thereby increasing the versatility of the apparatus.

[0058] In the example shown in FIG. 5, in the blow air introduction timing selection field ("Blow timing select") on the screen of the display 190, the blow air introduction control can be switched by selecting either a first blow air introduction control means (timer control: "Blow timer") that determines the timing to start introducing blow air consisting of primary air and secondary air based on a timer (elapsed time) or a second blow air introduction control means (position control: "Stretch Position") that determines the timing to start introducing blow air consisting of primary air and secondary air based on the actual position (lowered position) of the stretch rod.

[0059] As described above, according to the manufacturing apparatus and method for resin containers (hollow containers) disclosed herein, even under conditions in which the stretch blow molding time is very short (high cycle conditions), the preform can be appropriately stretched to stably produce high-quality resin containers (hollow containers).

[0060] Furthermore, according to the manufacturing method of a resin container (hollow container) according to the present disclosure, the supply control means 183 switches the blow air introduced into the preform 10 from primary air to secondary air based on the detected actual position of the stretch rod 145. This makes it possible to appropriately coordinate the movement of the stretch rod 145 with the respective introduction start times of the primary air and secondary air, and as a result, it is possible to appropriately stretch the preform and manufacture a high-quality resin container (hollow container).

[0061] In addition, in the manufacturing method of a resin container (hollow container) according to the present disclosure, a first position P1, which is a reference position for starting to introduce primary air, and a second position P2, which is a reference position for starting to introduce secondary air with a higher pressure than the primary air, are set. The supply control means 183 starts to introduce primary air when the actual position of the stretch rod 145 reaches the first position P1, and starts to introduce secondary air when the actual position of the stretch rod 145 reaches the second position P2, which is located lower than the first position P1. Specifically, when the detection means 182 detects that the actual position of the stretch rod 145 is at the second position P2, the supply control means 183 switches the blow air introduced into the preform 10 from primary air to secondary air. Therefore, according to the manufacturing method of a resin container (hollow container) according to the present disclosure, the blow air can be switched accurately based on the actual position of the stretch rod 145. That is, it is possible to perform horizontal axis stretching (stretching in the horizontal axis direction) of the preform 10 by the primary air and the secondary air so as to correspond to the vertical axis stretching (stretching in the vertical axis direction) of the preform 10 by the stretch rod 145, and the vertical axis stretching and the horizontal axis stretching can be performed in a more coordinated manner. In addition, according to the manufacturing method of a resin container (hollow container) according to the present disclosure, the introduction of secondary air is started when it is detected that the actual position of the stretch rod 145 is at the second position P2 located below the first position P1. In other words, the introduction of secondary air is performed at an appropriate timing by position control based on the actual position of the stretch rod 145, so that it is possible to prevent the container from being misaligned or having a poor thickness distribution. In addition, in order to improve the quality of the container, such as its rigidity, it is necessary to increase the degree of orientation crystallinity of the resin material that constitutes the container. In order to increase the degree of orientation crystallinity, it is effective to increase the stretching speed of the resin material (moving the stretch rod at high speed (lowering operation) and introducing blow air in a short time to stretch the preform in a short time). However, when the stretching speed of the resin material is increased, it becomes difficult to properly time the movement of the stretching rod and the introduction of blow air when using a timer control system.In contrast, according to the resin container (hollow container) manufacturing apparatus and manufacturing method of the present disclosure, even if the stretching speed of the resin material is increased, it is easy to appropriately match the movement of the stretch rod 145 and the timing of the introduction of blow air, and even under conditions where the molding cycle time is shortened, containers of higher quality than before can be manufactured.

[0062] Second Embodiment Next, a second embodiment of the present disclosure will be described in detail with reference to Figures 6 to 8. In the description of the second embodiment, parts that overlap with the description of the first embodiment will be omitted as appropriate. The second embodiment differs from the first embodiment in that the primary air is switched to the secondary air when a predetermined waiting time has elapsed since the stretch rod 145 moved (lowered) to the second position P2.

[0063] Fig. 6 is a diagram illustrating the position of the stretch rod 145 at each time. Fig. 7 is a diagram illustrating the molding procedure of the hollow container 20A by the stretch blow molding unit 140A according to the second embodiment. In this specification, the time during which the stretch rod 145 is lowered from the initial position to the second position P2 (time from time t0 to time t2) is called the stretching time, the time during which the stretch rod 145 is stopped at the second position P2 and the primary air is introduced into the preform 10 (time from time t2 to time t3) is called the first waiting time, the time during which the stretch rod 145 is stopped at the second position P2 and the secondary air is introduced into the preform 10 (time from time t3 to time t4) is called the second waiting time, and the time during which the stretch rod 145 is raised from the second position P2 to the initial position (time from time t4 to time t6) is called the retreating time. In the example shown by the solid line in FIG. 6 in the second embodiment, the second position P2 and the third position P3 are set to the same position.

[0064] 6, from time t0 to time t1, the stretch rod 145 descends to a first position P1. This causes the preform 10 to stretch in the vertical axis direction. On the other hand, since no blow air is introduced into the preform 10 between time t0 and time t1, the preform 10 does not stretch in the horizontal axis direction (FIG. 7(a)).

[0065] From time t1 to time t2, the stretch rod 145 does not stop at the first position P1, but descends from the first position P1 to the second position P2. That is, the stretch rod 145 continues to descend during the stretching time, and the preform 10 continues to stretch in the vertical axis direction. Meanwhile, the detection means 182 detects that the stretch rod 145 has descended to the first position P1 at time t1, and transmits the detection result to the supply control means 183. Based on the detection result, the supply control means 183 controls the supply unit 160 to introduce primary air into the preform 10. As a result, primary air begins to be introduced into the preform 10 at time t1. When the primary air is introduced into the preform 10, the preform 10 stretches in the horizontal axis direction (FIG. 7(b)).

[0066] Next, the actual position of the stretch rod 145 during the first waiting time and the blow air introduced into the preform 10 will be described. At time t2, the detection means 182 detects that the stretch rod 145 has descended to the second position P2, and transmits the detection result to the drive control means 181. Based on the detection result, the drive control means 181 controls the stretch rod 145 so that the stretch rod 145 stops at the second position P2 from the time when it is detected that the actual position of the stretch rod 145 is at the second position P2 until the first waiting time and the second waiting time have elapsed (i.e., the time from time t2 to time t4). Therefore, during the first waiting time and the second waiting time, the stretch rod 145 stops at the second position P2. In addition, the detection means 182 also transmits the detection result to the supply control means 183 at time t2. The supply control means 183, which has received the detection result, controls the supply unit 160 to switch the blow air introduced into the preform 10 from primary air to secondary air when a predetermined first waiting time preset by the operator has elapsed from the time when it was detected that the actual position of the stretch rod 145 is at the second position P2 (i.e., when it reaches time t3). That is, the second position P2 in this embodiment is a position that is a starting point (reference) when the supply control means 183 starts counting the time when the secondary air starts to be introduced into the preform 10. Since the supply control means 183 controls the supply unit 160 as described above, primary air continues to be introduced into the preform 10 during the first waiting time. Therefore, at time t2, the approximately central part in the vertical axis direction of the side surface of the preform 10 is in a state where it is expanded in the horizontal axis direction more than the other parts (FIG. 7(c)), but at time t3, the preform 10 is in a state where sufficient primary air has been introduced (FIG. 7(d)). Then, at time t3, the introduction of secondary air with a higher pressure than the primary air begins.

[0067] Next, the actual position of the stretch rod 145 and the blow air introduced into the preform 10 from time t3 to time t6 (the second waiting time and the retreating time) will be described. As described above, during the second waiting time, the stretch rod 145 stops at the second position P2. That is, as shown by the solid line in FIG. 6, the second position P2 and the third position P3 are the same position. At time t4, the drive control means 181 controls the stretch rod 145 so as to raise the stretch rod 145 from the second position P2 to the initial position. That is, at time t4, the stretch rod 145 starts to move upward relative to the bottom of the preform 10. Also, at time t6, the detection means 182 detects that the stretch rod 145 has risen to the initial position and transmits the detection result to the drive control means 181. Based on the detection result, the drive control means 181 controls the stretch rod 145 so as to stop the stretch rod 145 at the initial position. Therefore, during the retreat time, the stretch rod 145 continues to rise, and at time t6, the rise of the stretch rod 145 stops. Meanwhile, from time t3 to time t5, secondary air continues to be introduced into the preform 10. As a result, at time t5, the preform 10 becomes the hollow container 20A, which is the final molded product (FIG. 7(e)). Note that the supply control means 183 controls the supply unit 160 to stop the supply of blow air and exhaust it at time t5. Therefore, from time t5 to time t6, the blow air is not supplied to the preform 10 but is exhausted.

[0068] FIG. 8 is a diagram showing an example of the display of the display 190A according to the second embodiment. As illustrated in FIG. 8, the display 190A according to the second embodiment is provided with a main display section 191A capable of setting and displaying various information (control conditions, set values, etc.) as necessary, and a sub-display section 192 having the same configuration as that of the first embodiment. The main display section 191A is different from the main display section 191 according to the first embodiment in that a setting and display area for timer control (Timer) by the supply control means 183 is provided next to (to the right in FIG. 8) the display area for secondary blow (Sec.), and in that a third blow air introduction means (position and timer combined control "Stretch Position 2") is added, which determines the start timing of introduction of blow air consisting of primary air and secondary air based on both the lowering position of the stretch rod and the dimer (time lapse). In the setting area for timer control (Timer), a time corresponding to the first waiting time is input (set). In addition, the display area for timer control (Timer), the actual value of the first waiting time is displayed. For example, when an operator performs a predetermined input operation on the timer control (Timer) according to the resin container to be manufactured, the supply control means 183 controls the supply section 160 so that the blow air introduced into the preform 10 is switched from primary air to secondary air when the time input by the operator has elapsed from the time when the stretch rod 145 descends to the second position P2.

[0069] Incidentally, for example, when manufacturing a relatively large resin container (e.g., a 1500 ml container), it is necessary to introduce more primary air into the preform 10 before starting to introduce secondary air, compared to when manufacturing a small resin container (e.g., a 500 ml container). This is because a large resin container needs to have a larger width in the horizontal axis direction than a small resin container, and if secondary air is introduced into the preform 10 without sufficient primary air being introduced into the preform 10, there is a risk that a poor quality container will be manufactured.

[0070] According to the manufacturing apparatus and manufacturing method for a resin container (hollow container) according to the present disclosure, the supply control means 183 controls the supply unit 160 to switch the blow air introduced into the preform 10 from the primary air to the secondary air when a predetermined first waiting time (the time from time t2 to time t3) has elapsed since the time when the detection means 182 detected that the actual position of the stretch rod 145 is at the second position P2. Therefore, the primary air continues to be introduced into the preform 10 until the predetermined first waiting time has elapsed since the detection means 182 detected that the actual position of the stretch rod 145 is at the second position P2, and then the secondary air starts to be introduced into the preform 10. Therefore, it is possible to introduce sufficient primary air into the preform 10 before the secondary air is introduced into the preform 10. In this way, the injection stretch blow molding apparatus 100A according to the second embodiment can introduce more primary air into the preform 10 before the secondary air is introduced, compared to the injection stretch blow molding apparatus 100 according to the first embodiment, so that a good quality container can be manufactured, especially when a relatively large resin container is manufactured. Furthermore, according to the manufacturing apparatus and manufacturing method for a resin container (hollow container) according to the present disclosure, even if the molding cycle time is short (the speed at which the stretch rod 145 descends is fast), the vertical axis stretching of the preform 10 by the stretch rod 145 and the horizontal axis stretching of the preform 10 by the primary air and the secondary air can be performed in harmony by combining the position control based on the actual position of the stretch rod 145 and the timer control. Therefore, the injection stretch blow molding apparatus 100A can appropriately stretch the preform 10, and as a result, a high-quality resin container (hollow container) can be manufactured.

[0071] Furthermore, according to the manufacturing apparatus and method for a resin container (hollow container) of the present disclosure, secondary air is introduced into the preform 10 during a time period (between time t3 and time t5) including the second waiting time (between time t3 and time t4). Therefore, the stretch rod 145 starts to move (rise) toward the initial position after a certain amount of secondary air has been introduced into the preform 10. Therefore, according to the injection stretch blow molding apparatus 100A, it is possible to prevent the container from taking an unintended shape.

[0072] Furthermore, the present disclosure is not limited to the above-described embodiment. For example, in the above-described embodiment, the stretch blow molding section (stretch blow molding mold) has four cavities arranged in a row, but the number of cavities is not particularly limited and may be, for example, eight, twelve, etc.

[0073] In the second embodiment, the drive control means 181 controls the stretch rod 145 so that the stretch rod 145 stops at the second position P2 during the first waiting time and the second waiting time, but the present invention is not limited to this example. For example, as shown by the dashed line in FIG. 6, the drive control means 181 may control the stretch rod 145 so that the stretch rod 145 stops at the second position P2 during the first waiting time, and control the stretch rod 145 so that the stretch rod 145 further descends from the second position P2 to a third position P3 during the second waiting time. In this case, the detection means 182 detects that the stretch rod 145 has descended to the bottom of the hollow container 20A at time t4, for example, and transmits the detection result to the drive control means 181. Then, the drive control means 181 controls the stretch rod 145 so that the stretch rod 145 is raised to the initial position based on the detection result.

[0074] This application is based on a Japanese patent application (Patent Application No. 2019-071569) filed on April 3, 2019, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0075] 10 Preform 20,20A Hollow vessel 100,100A Injection stretch blow molding machine 110 Injection molding department 111 Mold clamping mechanism 120 Cooling section 130 Heating section 140,140A Stretch blow molding section 141 Blow cavity type 141a Cavity 142 Bottom type 143 Blow core type 144 Stretch blow molding mold 145 Extension Rod 146 Blow mold fixing plate 147 Mold clamping device 150 Conveyor 151 Conveyor Line 152 Transport fixture 153 Sprocket 155 Grip mechanism transport section 156 Reversal section 160 Supply section 170 Drive unit 171 Servo motor 180 Control Unit 181 Drive control means 182 Detection Methods 183 Supply Control Means 184 Display control means 190,190A Display 191,191A Main display 192 Sub display 193 Header section 194 Footer

Claims

1. A resin container manufacturing apparatus comprising: a preform disposed in a stretch blow molding die is stretched by a stretch rod; and blow air is introduced into the preform to stretch the preform into a resin container, a control unit that switches the blow air supply operation by selecting one of a plurality of supply operations, The plurality of supplying operations include at least a first operation of supplying the blow air based on a timer, and a second operation of supplying the blow air based on an actual position of the stretch rod. Plastic container manufacturing equipment.

2. The control unit: a detection means for detecting an actual position of the stretch rod inserted into the preform; a supply control means for controlling a supply state of the blow air based on a detection result of the detection means, the manufacturing apparatus has a display means for displaying and inputting setting information for setting control conditions of various devices, The control unit is configured to select the blow air supply operation based on the setting information input to the display means. The resin container manufacturing apparatus according to claim 1 .

3. In the second operation, the supply control means introduces primary air as the blow air into the preform based on a detection result of the detection means indicating that the stretch rod has reached a first position, and switches the blow air from the primary air to secondary air having a higher pressure than the primary air based on a detection result of the detection means indicating that the actual position of the stretch rod has reached a second position. The resin container manufacturing apparatus according to claim 2 .

4. The plurality of supply operations further includes a third operation using the timer and the actual position of the stretch rod in combination. The resin container manufacturing apparatus according to claim 2 .

5. In the third operation, the supply control means introduces primary air as the blow air into the preform based on a detection result that the detection means has detected that the stretch rod has reached a first position, and when a first waiting time has elapsed from the time that the detection means detects that the actual position of the stretch rod has reached a second position, switches the blow air from the primary air to secondary air having a higher pressure than the primary air. The resin container manufacturing apparatus according to claim 4.

6. The driving source of the stretching rod is a servo motor, The resin container manufacturing device according to any one of claims 2 to 5, wherein the detection means detects an actual position of the stretch rod based on a rotational position of the servo motor.

7. A method for producing a resin container, comprising the steps of: stretching a preform placed in a stretch blow molding die using a stretch rod; and introducing blow air into the preform to stretch the preform into a resin container, the method comprising the steps of: The blow air supply control is switched by selecting one of a plurality of supply operations, The plurality of supplying operations include at least a first operation of supplying the blow air based on a timer, and a second operation of supplying the blow air based on an actual position of a stretch rod. A method for manufacturing a resin container.

8. The blow air supply operation is selected based on setting information input to a display means for displaying and inputting setting information for setting control conditions of various devices. The method for producing the resin container according to claim 7.

9. The second operation includes introducing primary air as the blow air into the preform when the actual position of the stretch rod reaches a first position, and switching the blow air from the primary air to secondary air having a higher pressure than the primary air when the actual position of the stretch rod reaches a second position. The method for producing a resin container according to claim 7 or 8.

10. The plurality of supply operations further includes a third operation using the actual position of the stretch rod and the timer in combination. The method for producing a resin container according to claim 7 or 8.

11. The third operation includes introducing primary air as the blow air into the preform when the actual position of the stretch rod reaches a first position, and switching the blow air from the primary air to secondary air having a higher pressure than the primary air when a predetermined first waiting time has elapsed from the time when the actual position of the stretch rod reaches a second position. The method for producing a resin container according to claim 10.

12. The method further includes detecting the actual position of the stretch rod based on a rotational position of a servo motor serving as a drive source of the stretch rod. The method for producing a resin container according to claim 7 or 8.

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