Method for controlling a manufacturing apparatus, method for manufacturing a resin container, control device for a manufacturing apparatus, and manufacturing apparatus for a resin container having the same.

Abstract

The present invention provides a control method for a manufacturing apparatus, a method for manufacturing a resin container, a control device for a manufacturing apparatus, and a resin container manufacturing apparatus having the same, which enable the air and preform inside the heating device to be heated to an appropriate temperature quickly. [Solution] A control method for a manufacturing apparatus that produces a resin container by blow molding a preform includes the steps of: acquiring a target temperature in a heating device that heats the preform to a suitable temperature for blow molding (S100); acquiring an actual temperature in the heating device detected by a sensor placed in the heating device (S110); calculating the temperature difference between the target value and the actual value (S120); and adjusting the heating capacity and cooling capacity of the heating device based on the temperature difference (S130).

Description

Technical Field

[0001] The present invention relates to a method for controlling a manufacturing apparatus, a method for manufacturing a resin container, a control apparatus for a manufacturing apparatus, and a manufacturing apparatus for a resin container having the same.

Background Art

[0002] Patent Document 1 discloses a blow molding machine for a resin container including at least a blow molding section, a heating section, and a conveyance path for conveying a preform heated in the heating section to the blow molding section.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A blow molding apparatus for manufacturing a large number of beverage containers or the like is required to have very high productivity and efficiency. This type of blow molding apparatus has a heating device that raises the temperature of the conveyed preform to the appropriate blow temperature. The heating device uses the radiant heat of near-infrared rays (light) from a near-infrared heater and the convective heat of high-temperature air (atmosphere) inside the heating device to heat the preform. If both the heater output and the atmosphere temperature are not appropriately adjusted, the preform cannot be heated to the appropriate temperature. A preform that is not at the appropriate blow temperature cannot be blow molded into a good container and is therefore discarded as it is. In addition, the air inside the heating device is heated and adjusted to a predetermined temperature by a heater and a blower, but this requires a relatively long time.

[0005] In this scenario, if the blow molding machine stops for any reason, the power to the heating device is usually also cut off. This means that the air inside the heating device will be outside the optimal temperature range, both before operation starts and during pauses, requiring temperature increases and adjustment. There is a need for a heating method and device that can reduce the amount of wasteful preform and allow for quick startup.

[0006] The present invention aims to provide a method for controlling a manufacturing apparatus, a method for manufacturing a resin container, a control device for the manufacturing apparatus, and a manufacturing apparatus for resin containers having the same, which can quickly raise the temperature of the air and preform inside the heating device to an appropriate temperature. [Means for solving the problem]

[0007] A control method for a manufacturing apparatus according to one aspect of the present invention is: A control method for a manufacturing apparatus that blow-moldes a preform to produce a resin container, A step of obtaining a target temperature in a heating device that heats the preform to a suitable temperature for blow molding, A step of obtaining the actual temperature inside the heating device detected by a sensor placed inside the heating device, A step of calculating the temperature difference between the target value and the measured value, A step of adjusting the heating capacity and cooling capacity of the heating device based on the temperature difference, This is a method for controlling a manufacturing apparatus, including [specific details omitted].

[0008] A method for manufacturing a resin container according to one aspect of the present invention is: An injection molding process in which a bottomed resin preform is injection molded, A method for manufacturing a resin container, comprising: a blow molding step, in which a preform molded in the injection molding step is blow-molded to manufacture a resin container, This is a method for manufacturing a resin container, comprising implementing the above-described control method for the manufacturing apparatus in order to heat the preform molded in the injection molding process to a suitable temperature for blow molding.

[0009] A control device for a manufacturing apparatus according to one aspect of the present invention is: A control device for a manufacturing apparatus that blow-moldes a preform to produce a resin container, A target value acquisition unit that acquires a target temperature in a heating device that heats the preform to an appropriate temperature for blow molding, A unit for acquiring actual values ​​of the temperature inside the heating device, which is detected by a sensor placed inside the heating device, A calculation unit that calculates the temperature difference between the target value and the measured value, An adjustment unit that adjusts the heating capacity and cooling capacity of the heating device based on the temperature difference, This is a control device for a manufacturing apparatus, including [specific components / features].

[0010] A manufacturing apparatus for resin containers according to one aspect of the present invention is: An injection molding section for injection molding a resin preform with a bottom, A heating section including a heating device for heating the preform to a suitable temperature for blow molding, A blow molding section for manufacturing a resin container by blow molding a preform heated in the aforementioned heating section, The control device of the above manufacturing apparatus, This is a manufacturing apparatus for resin containers having [specific features / features]. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a method for controlling a manufacturing apparatus, a method for manufacturing a resin container, a control device for the manufacturing apparatus, and a manufacturing apparatus for resin containers having the same, which can quickly raise the temperature of the air and preform inside the heating device to an appropriate temperature. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic plan view of a blow molding apparatus. [Figure 2] This is a schematic side view of a blow molding machine. [Figure 3] This is a plan view of the transport section. [Figure 4] This is a block diagram of the control device. [Figure 5]The figure shows an example of the display unit showing elements of the operation state of the blow molding device. [Figure 6] The figure shows an example of the display unit showing the target value and the measured value of the temperature inside the heating device. [Figure 7] The figure shows another example of the display unit showing the target value and the measured value of the temperature inside the heating device. [Figure 8] The figure shows an example of the flow of the control method. [Figure 9] The figure shows the internal state of the heater box provided in the heating unit of a specific embodiment. [Figure 10] The figure shows the external state of the heater box provided in the heating unit of a specific embodiment. [Figure 11] The figure shows a pipeline for introducing cooling air into the heater box.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensions of each member shown in these drawings may differ from the actual dimensions of each member for the sake of convenience of explanation.

[0014] Also, in the description of this embodiment, for the sake of convenience of explanation, the "left - right direction", "front - back direction", and "up - down direction" will be referred to as appropriate. These directions are relative directions set for the blow molding device shown in FIGS. 1 and 2. Here, the "up - down direction" is a direction including the "upward direction" and the "downward direction". The "front - back direction" is a direction including the "front direction" and the "rear direction". The "left - right direction" is a direction including the "left direction" and the "right direction".

[0015] Figure 1 is a schematic plan view showing the overall appearance of a blow molding apparatus 1 for resin containers according to an embodiment (an example of a manufacturing apparatus for resin containers). Figure 2 is a schematic side view showing the overall appearance of the blow molding apparatus 1 according to an embodiment. The blow molding apparatus 1 includes an injection molding section 100 for molding a resin preform 10, a blow molding section 500 for blow molding the preform 10 to form a container 20, and a transport section 300 for transporting the preform 10 molded in the injection molding section 100 to the blow molding section 500 (Figure 1). The blow molding apparatus 1 is a hot parison type (1.5 stage type) blow molding apparatus that blow molds M preforms at a time in n stages from N preforms 10 that are simultaneously injection molded.

[0016] The blow molding apparatus 1 includes an extraction device 150 for extracting the preform 10 from the injection molding unit 100, a preform transfer device 220 for transferring the preform 10 from the extraction device 150, and a first inversion unit (post-cooling unit) 200 for sending the preform 10 from the preform transfer device 220 to the transport unit 300 (Figure 2). The blow molding apparatus 1 also includes a second inversion unit 400 for sending the preform 10 from the transport unit 300 to the blow molding unit 500 (Figure 2). The blow molding apparatus 1 also includes a control device 600 and an input / output device 700 (Figures 1 and 2).

[0017] The injection molding unit 100 is configured to simultaneously injection mold M (M=N / n: M is a natural number) preforms 10 in each of n (n is an integer of 2 or more) rows parallel to the left and right directions. The injection molding unit 100 includes an injection device 110 for injecting resin, an injection core mold 120, an injection neck mold (not shown), an injection cavity mold 130, and a clamping mechanism that drives clamping along four tie bars 140. As shown in Figure 1, the number of preforms N simultaneously injection molded in the injection molding unit 100 may be, for example, a maximum of 24 (3 rows × 8 preforms). If the preform diameter is large, there may be an arrangement of 4 preforms in each row, for a total of N=12 preforms in 3 rows.

[0018] The extraction device 150 is configured to extract N preforms 10 molded in the injection molding section 100. The extraction device 150 is configured to allow N (for example, 3 rows x 8) holding members 152 (for example, pots) to move horizontally between a receiving position P1 below the injection core mold 120 and a transfer position P2 outside the space enclosed by the tie bars 140.

[0019] The preform transfer device 220 transfers N preforms 10, held by three rows of holding members 152 of the extraction device 150 at the transfer position P2 shown in Figure 2, to the first reversal unit 200. The preform transfer device 220 includes a preform holder 222, a first transfer mechanism 224 that moves the preform holder 222 up and down, and a second transfer mechanism 226 that moves the preform holder 222 and the first transfer mechanism 224 horizontally in the front-rear direction. For example, an air cylinder or a servo motor can be used as the drive source for the first and second transfer mechanisms 224 and 226.

[0020] The first inversion section 200 is a part for post-cooling (additional cooling) of the preform 10, and is configured to invert the upright preform 10 molded in the injection molding section 100 into an inverted state with the neck facing downwards, and transfer it to the transport section 300. The first inversion section 200 is equipped with a first inversion member 210. The first inversion member 210 has N first inversion pots 212 and N second inversion pots 214 provided opposite the first inversion pots 212. The first inversion pots 212 and the second inversion pots 214 (first inversion member 210) are configured to be able to invert intermittently by 180° around their axis. The first inversion member 210 is configured to be able to move up and down by a ball screw or the like driven by a drive source 216 (e.g., a servo motor).

[0021] The transport unit 300 is configured to transport the preform 10, which has been transported from the injection molding unit 100 via the first reversing unit 200 to the transport unit 300, to the blow molding unit 500. Figure 3 is a plan view showing one embodiment of the transport unit 300. The transport unit 300 comprises a plurality of first transport members 310 configured to support the preform 10. The M first transport members 310 are connected by connecting members to form a set of first transport members 310. The connecting members of a set of first transport members 310 are configured to be driven by a first transport drive unit 320 and a second transport drive unit 330, which will be described later. In Figure 3, the position of the leading first transport member 310 (or preform 10) in a set of first transport members 310 is marked with a double circle to distinguish it from the other seven. Each first transport member 310 is configured to be rotatable around an axis. Note that the first transport members 310 may not be connected. In this case, members that mesh with continuous or intermittent drive members such as sprockets are provided on each first conveying member 310.

[0022] The transport unit 300 is equipped with a loop-shaped transport path made of guide rails and the like, and is configured to transport the first transport member 310 in a circular manner along the transport path. The transport unit 300 is equipped with a first transport drive unit 320 which consists of a plurality of sprockets 320a, 320b, 320c, and 320d that continuously drives the first transport member 310, and a second transport drive unit 330 which consists of sprockets 330a, 330b, and 330c that intermittently drives the first transport member 310. In the first transport drive unit 320, the sprockets are arranged in the order of sprocket 320d, sprocket 320c, sprocket 320b, and sprocket 320a from the upstream side. In the second transport drive unit 330, the sprockets are arranged in the order of sprocket 330a, sprocket 330b, and sprocket 330c from the upstream side.

[0023] The region in which the first transport member 310 is continuously driven by the first transport drive unit 320 is the continuous transport region T1, and the region in which the first transport member 310 is intermittently driven by the second transport drive unit 330 is the intermittent transport region T2. ​​The continuous transport region T1 is located upstream of the transport section 300 compared to the intermittent transport region T2. ​​The continuous transport region T1 is provided with a heating section 360 that heats the preform 10 to a temperature suitable for blow molding. The heating section 360 is arranged in a path spanning sprockets 320c, 320b, and 320a in the continuous transport region T1. The heating section 360 can be configured by arranging a heating device, including heating elements such as quartz heaters and flat reflectors, which are arranged in multiple stages in the height direction (up and down direction) and spaced apart in the transport direction, so as to surround the transport section 300 in the continuous transport region T1. Inside the heating section 360, a blower is configured to blow air from the back of the heater.

[0024] Furthermore, the transport unit 300 is located below the first reversing unit 200 and includes a parallel drive device 370 that drives a set of first transport members 310 in parallel, consisting of (n+1) or more (for example, four (four rows)) (Figure 2). The parallel drive device 370 is constructed by attaching both ends of multiple transport rails to two chains 374 stretched across two sprockets 372a and 372b at each of the front and rear ends. When one of the sprockets 372a and 372b is rotated by one step, the transport rail is moved by one step. The leading row of a set of first transport members 310 arranged in the parallel drive device 370 is configured to be pushed to the left by an unloading device (not shown), such as an air cylinder. As a result, the set of first transport members 310 on which the preform 10 is mounted sequentially mesh with the continuously driven sprockets 320d and are transported continuously. The parallel drive unit 370 transports one pair of first transport members 310 to the left, and then transports the other pair of first transport members 310 forward by one step. The last row of the parallel drive unit 370 is configured to receive a pair of first transport members 310 that does not have a preform 10 on it, which is sent from the sprocket 330c.

[0025] The leading first conveying member 310 of a pair of first conveying members 310 in the leading row is discharged by the discharge device and engages with the upstream sprocket 320d, thereby applying continuous conveying force from the sprocket 320d to the pair of first conveying members 310. The driving force applied to each pair of first conveying members 310 that engages with the four continuously driven sprockets 320a, 320b, 320c, and 320d present in the continuous conveying region T1 pushes another pair of first conveying members 310 upstream that are not engaged with the continuously driven sprockets, and multiple pairs of first conveying members 310 are continuously conveyed along the conveying direction of the continuous conveying region T1.

[0026] The second inversion unit 400 is positioned between sprocket 330a and sprocket 330b in the intermittent transport region T2 of the transport unit 300 (Figures 1 and 2). The second inversion unit 400 includes a second inversion member (not shown) that inverts the preform 10, which has been transported by the transport unit 300 to the position of the second inversion unit 400, from an inverted state to an upright state and hands it over to the blow molding unit 500. The second transport drive unit 330 intermittently drives a pair of first transport members 310 so that the pair of first transport members 310 stops for a predetermined time at the position of the second inversion unit 400.

[0027] The blow molding unit 500 is configured to mold a resin container 20 by stretching M preforms 10 with blown air. The blow molding unit 500 includes a blow cavity mold which is a split mold that can be opened and closed in the left and right directions and defines the shape of the body of the container 20, a bottom mold which can be raised and lowered and defines the bottom of the container 20, and a second transport member 530 for transporting the preforms 10 and the container 20 in the front and back directions. In addition to these, the blow molding unit 500 may also include a stretching rod, a blow core mold, a neck mold, etc. If a stretching rod is included, the resin container 20 is molded by biaxial stretching using blown air and vertical axis drive of the stretching rod.

[0028] The second transport member 530 is a chuck member that grips the neck portions of M preforms 10 or containers 20 and transports them intermittently. The second transport member 530 has a holding arm that grips the neck portions of the preforms 10 or containers 20. The second transport member 530 integrally has an input section 534 and an output section 536 and is configured to reciprocate in the front-rear direction. This reciprocating drive is realized, for example, by a servo motor. Due to this reciprocating drive, the input section 534 reciprocates between the preform receiving position B1 and the blow molding position B2, and the output section 536 reciprocates between the blow molding position B2 and the removal position B3. The holding arm is driven to open and close in the left-right direction integrally by the driving force of, for example, an air cylinder. Furthermore, the row pitch (distance between each preform) in each holding arm of the loading section 534 is configured to be convertible from a narrow pitch at the preform receiving position B1 to a wider pitch at the blow molding position B2 when moving from the preform receiving position B1 to the blow molding position B2.

[0029] The control device 600 is a device that controls the blow molding apparatus 1. Figure 4 is a block diagram showing the configuration of the control device 600 according to this embodiment. The control device 600 comprises a processor 610, a main memory 630, a storage 650, and an interface 670. The storage 650 stores a program for controlling the blow molding apparatus 1. Examples of the storage 650 include a Hard Disk Drive (HDD), a Solid State Drive (SSD), and non-volatile memory. The processor 610 reads the program from the storage 650, loads it into the main memory 630, and executes processing according to the program. The processor 610 also allocates storage space in the main memory 630 or storage 650 according to the program. By executing the program, the processor 610 functions as a target value acquisition unit 612, a measured value acquisition unit 614, a calculation unit 616, an adjustment unit 618, and a cycle time control unit 620.

[0030] The target value acquisition unit 612 acquires a target temperature value for the heating device of the heating unit 360, which heats the preform 10 to the appropriate temperature for blow molding. This target value may be an input value from the input unit 720 of the input / output device 700, which will be described later, or it may be a target value that has been previously stored in the storage 650.

[0031] The measured value acquisition unit 614 acquires the actual temperature inside the heating device detected by a sensor placed inside the heating device of the heating unit 360. The calculation unit 616 calculates the temperature difference between the target value acquired by the target value acquisition unit 612 and the actual value acquired by the measured value acquisition unit 614.

[0032] The adjustment unit 618 adjusts the heating capacity and cooling capacity of the heating device based on the temperature difference calculated by the calculation unit 616. For example, heating capacity refers to the output of the heater, and cooling capacity refers to the output of the blower. If the heating device of the heating unit 360 is provided in a plurality of predetermined regions, the adjustment unit 618 may function as a divided adjustment unit that adjusts the heating capacity and cooling capacity of each predetermined region. As predetermined regions, for example, the region between sprocket 320c and sprocket 320b may be designated as Zone 1, and the region between sprocket 320b and sprocket 320a may be divided into three equal parts, with the two upstream parts of the three equal parts designated as Zone 2 and the remaining part as Zone 3 (see Figure 5 below). A temperature sensor may be provided in each of the predetermined regions. However, the adjustment of the heating capacity and cooling capacity of each predetermined region may be adjusted based on the measured temperature of one predetermined region.

[0033] The cycle time control unit 620 controls the injection molding unit 100 of the blow molding apparatus 1 to extend the cycle time of injection molding of the preform 10 in the injection molding unit 100 until the temperature inside the heating device reaches a target value.

[0034] The input / output device 700 comprises a display unit 710 and an input unit 720. The input unit 720 consists of input devices such as buttons and a keyboard for inputting control instructions for the blow molding apparatus 1. The display unit 710 consists of a display device such as a display for outputting operating information of the blow molding apparatus 1.

[0035] Figure 5 shows an example of how the display unit 710 displays elements of the operating status of the blow molding apparatus 1. More specifically, Figure 5 is an example of a screen for checking and setting information related to the ambient temperature inside the heating device and the heating conditions of the preform 10.

[0036] In Figure 5, the measured air temperature (ambient temperature) in each predetermined area (Zone 1, Zone 2, Zone 3) within the heating device is displayed under "Heater box temperature". The measured temperature (surface temperature) of the preform 10 is displayed under "Preform temperature". Of these, the measured temperature before heating is displayed under "Before reheating", and the measured temperature after heating is displayed under "After reheating". Furthermore, the maximum and minimum values ​​of these are displayed under "Max" and "Min", respectively. The temperature setting value for the preform 10 that enables blow molding is displayed under "Blow", the minimum temperature setting value is displayed under "Low", and the maximum temperature setting value is displayed under "High". The value shown under "Blow" can be set by the operator's input.

[0037] The output settings for the multiple blowers that circulate outside air within the heating device are displayed under "Blower," the output settings for the blowers used to cool the preform (especially the neck) are displayed under "Preform cooling," and the output settings for the blowers used to adjust the temperature of the air (ambient) inside the heating device are displayed under "Zone1" and "Zone2,3," respectively. The values ​​shown under "Blower" can be set by the operator. Note that the "Blower" settings shown in Figure 5 become invalid when performing the temperature adjustment shown in Figure 6, which will be described later. In addition, the flow rate setting for the refrigerant used to prevent overheating of the heating device is displayed in the right-hand box of "Flow" under "Chiller water," and the measured value is displayed in the left-hand box of "Flow." The refrigerant flow rate setting displayed in the right-hand box of "Flow" can be set by the operator. The measured temperature of the refrigerant is displayed under "Temp."

[0038] Figure 6 shows an example of how the display unit 710 displays the target temperature and the measured temperature inside the heating device. More specifically, Figure 6 shows an example of a screen that allows the ambient temperature inside the heating device to be quickly raised and adjusted to the target temperature. In Figure 6, the difference between the target ambient temperature and the measured temperature at which automatic temperature control of the heating device is started is set, and the output of the heater and blower is set according to that difference.

[0039] In Figure 6, the measured ambient temperature of a predetermined area is displayed in "Heater box temperature". In Figure 6, the target ambient temperature of a predetermined area is displayed in "Target". At least one set value for the temperature difference between the target ambient temperature and the measured value for starting automatic heating control (automatic temperature adjustment control) is displayed in "Temperature difference" (four in Figure 6). This temperature difference set value can be set by the operator.

[0040] Furthermore, in Figure 6, the degree to which the heating and cooling capacities are adjusted according to the temperature difference between the target value and the measured value, i.e., the output settings of the heater and blower, are displayed in "Preform Heater" and "Blower," respectively. These heater and blower output settings can be set by operator input. To change the degree of adjustment of the heating and cooling capacities for each temperature difference, multiple temperature differences are set, and the heater and blower output values ​​are set for each temperature difference. In automatic temperature rise control, the heater and blower output values ​​can be set for predetermined areas with different locations within the heating device (at least three locations for the heater: "Zone 1," "Zone 2," and "Zone 3," and at least three locations for the blower: "Preform cooling," "Zone 1," and "Zone 2, 3"). Also in Figure 6, the degree to which the cycle time of injection molding of the preform 10 in the injection molding unit 100 is extended is displayed in "Cycle."

[0041] According to the adjustment shown in Figure 6, for example, if the measured value is 9°C lower than the target value (-9°C), the heater output is increased by 10% from the molding set value (the actual heater output value set for molding, not shown), and the blower output is decreased by 20% from the molding set value (the actual blower output value set for molding, not shown). Next, as the temperature rises, for example, when the measured value is 4°C lower than the target value (-4°C), the heater output is increased by 5% from the molding set value, and the blower output is decreased by 10% from the molding set value. This control is repeated, and the measured value approaches the target value. In this way, the heater and blower outputs are adjusted stepwise and automatically according to the measured value, so the ambient temperature can be brought closer to the target value quickly and automatically without burdening the operator. Note that the heater and blower set values ​​can be either a percentage increase or decrease relative to the molding set value, or the actual output value. In Figure 6, the heater and blower set values ​​are set as percentage increases or decreases relative to the molding set value.

[0042] Furthermore, the settings for the heater output and blower output in each predetermined area do not have to be uniform and may differ in each predetermined area. For example, the output may not be limited to changing the output for each of "Zone 1," "Zone 2," and "Zone 3," but the output of some of the heaters arranged in a multi-stage configuration in the vertical direction (e.g., the bottom heater) may be set independently of the output of the other heaters (for example, by providing a separate display and setting screen for the bottom heater, "Preform Heater"). This allows the output of the bottom heater, which is located closest to the reflector, to be controlled independently and used to quickly heat up the reflector, thereby accelerating the rate at which the ambient temperature rises due to heat dissipation from the reflector.

[0043] Furthermore, the heater output and blower output settings for each predetermined region may be continuously changed by feedback control according to the measured values. In particular, it is preferable to control them using a decay curve that changes steplessly according to the measured values. Moreover, in the initial period, since the difference between the measured ambient temperature and the target value is large, the heater and blower are output uniformly based on the set values ​​(heater output: high, blower output: low). In the transitional and final periods, when the measured value approaches the target value, the heater output and blower output may be changed stepwise or continuously by feedback control according to the measured values. In particular, it is preferable to control them using a decay curve that changes steplessly according to the measured values. The temperature at which the control is switched may be set separately on the screen or incorporated into the program. This makes it possible to raise the temperature of the air (ambient) inside the heating device more quickly and appropriately. After the ambient temperature reaches the target value, the heater and blower outputs are adjusted based on predetermined heating conditions for molding (heating conditions when actually blow molding the preform), which are set separately.

[0044] Figure 7 shows another example of how the display unit 710 displays the target and measured temperatures inside the heating device. In Figure 7, the measured ambient temperature of a predetermined area is displayed under "Heater box temperature". In Figure 7, the target ambient temperature of a predetermined area is displayed under "Target". The set value for the temperature difference between the target and measured ambient temperatures for switching the automatic temperature rise control (automatic temperature adjustment control) is displayed under "Control start temp diff.". The target ambient temperature and the set value for the temperature difference can be set by the operator.

[0045] Furthermore, in Figure 7, the initial output of the heater and blower is displayed in "Heater power setting when control start" and "Blower setting when control start," respectively. The initial output of the heater and blower can be set by operator input. In the example shown in Figure 7, the output of the heater and blower is controlled based on a decay curve (nth-order curve, etc.) that changes steplessly according to the measured value, starting when the temperature difference between the target value and the measured value of the ambient temperature falls below the setting value for switching automatic heating control. The decay curve is calculated from a predetermined exponential function incorporated into the program. As long as the temperature difference between the target value and the measured value of the ambient temperature exceeds the setting value for switching automatic heating control, the heater and blower adjust the ambient temperature with the initial output (constant output). The control transition order (order) for the predetermined exponential function used to calculate the decay curve in controlling the output of the heater and blower is displayed in "Transition order." The setting value for the control transition order can be set by operator input. Furthermore, the initial output of the heater is "1" for the first stage (bottommost heater) of a multi-stage arrangement of heaters in the vertical direction (up and down direction). st It is displayed in the row "Stage", and for the second stage and above (heaters above the first stage), it says "Over 2 nd This is displayed in the row labeled "Stage". The columns "Heater power setting when control start" and "Blower setting when control start" correspond to the following locations in the diagram, from left to right: "Zone 1", "Zone 2", and "Zone 3" for the heater, and "Preform cooling", "Zone 1", and "Zone 2, 3" for the blower. The initial output settings for the heater and blower can be either a percentage increase or decrease relative to the molding setting, or the actual output value. In the example in Figure 7, the heater and blower settings are the actual output values.

[0046] According to the adjustment shown in Figure 7, the heater and blower outputs are initially kept constant (set value: output in the initial state) (the heater output is changed between the first stage and the second stage and above). When the difference falls within a certain range (within 20°C in the example in Figure 7), the output value is changed curvilinearly, and the operation of the heating device is controlled to finally reach the output value during actual molding. In this way, the heater and blower outputs are switched according to the measured values, and from the point when the temperature difference between the target ambient temperature and the measured value falls below the set value for switching the automatic heating control, the heater and blower outputs are continuously adjusted based on the decay curve. This allows the ambient temperature to approach the target value quickly and automatically without burdening the operator.

[0047] The following describes a method for manufacturing a resin container using a blow molding apparatus 1 equipped with a control device 600 according to this embodiment. The method for manufacturing a resin container includes the steps of: injection molding a preform 10 in an injection molding section 100; transporting the preform 10 molded in the injection molding section 100 to a blow molding section 500; heating the preform 10 while it is being transported to the blow molding section 500; and blow molding the transported preform 10 into a container 20 in the blow molding section 500.

[0048] The injection molding process for the preform 10 involves injecting molten resin into the space formed by clamping the injection core mold 120, injection neck mold, and injection cavity mold 130 of the injection molding section 100, thereby molding N preforms (Figure 2).

[0049] The process of transporting the preform 10 molded in the injection molding section 100 to the blow molding section 500 includes a first transport step, a first transfer step, a second transport step, and a second transfer step. The first transport step is the process of removing the preform 10 from the injection molding section 100 with a removal device 150, and then transferring the preform from the removal device 150 to the first inversion section 200 with a preform transfer device 220 (Figure 2). The first transfer step is the process of inverting the preform 10 from an upright state to an inverted state with the first inversion section 200 and handing it over to the transport section 300 (Figure 2).

[0050] The second transport process involves transporting the preform 10 to the second inversion section 400 in the transport section 300 (Figure 1). In the second transport process, a pair of first transport members 310 in the leading row of the parallel drive unit 370 are transported to the left by the discharge device, and the preform 10 is transported to the second inversion section 400 via the continuous transport area T1 and the intermittent transport area T2 (Figures 1 and 2).

[0051] The second transfer step involves the second inversion unit 400 inverting the preform 10 from an inverted state to an upright state and transferring it to the second transport member 530 of the blow molding unit 500 (Figure 2). However, if the heating device of the heating unit 360 has not finished heating up, the preform 10 is not transferred to the blow molding unit 500, and the preform 10 is removed from the first transport member 310 by the sprocket 330c. The first transport member 310, without the preform 10 on it, is sent to the parallel drive unit 370 by the sprocket 330c (Figures 1 and 2).

[0052] The step of heating the preform 10 involves heating the preform 10 to a suitable temperature for blow molding during transport using a heating device in a heating unit 360 provided in the continuous transport area T1 of the transport unit 300.

[0053] The process of blow-molding the preform 10 into the container 20 involves transporting the preform 10 from the preform receiving position B1 to the blow-molding position B2 using a second transport member 530, clamping the blow cavity mold and bottom mold, and blowing air into the preform 10 to form the container 20. The container 20 is manufactured through these processes.

[0054] Figure 8 shows an example of a flow chart of the control method for the blow molding apparatus 1. As shown in Figure 8, the control method for the blow molding apparatus 1 includes a step of acquiring a target value for the temperature inside the heating device by a target value acquisition unit 612 (step S100), a step of acquiring an actual value for the temperature inside the heating device by a measured value acquisition unit 614 (step S110), a step of calculating the temperature difference between the target value and the measured value by a calculation unit 616 (step S120), and a step of adjusting the heating capacity and cooling capacity of the heating device by an adjustment unit 618 based on the temperature difference (step S130). The control method may also include a step in which the adjustment unit 618 functions as a divided adjustment unit to adjust the heating capacity and cooling capacity of each predetermined region (Zone 1, Zone 2, Zone 3) of the heating device. The control method may also include a step in which the cycle time control unit 620 extends the cycle time in the injection molding unit 100 until the temperature inside the heating device reaches a target value. For example, extending the molding cycle can be configured such that, by entering 1.5 in the "Cycle" field displayed on the display unit 710 in Figure 6, the molding cycle can be extended to 1.5 times the default cycle during heating. Alternatively, it may be set to automatically release when the atmosphere reaches the target value.

[0055] For example, in blow molding machines equipped with injection molding devices, a safety door is opened when certain operations such as purging are performed at the start or restart of operation. When the safety door is open, the blow molding machine and heating device are stopped. After the operations are completed, operation is started or restarted, but the air inside the heating device is outside the appropriate temperature range, so it is heated and adjusted. It can take several tens of minutes to heat and adjust the air inside the heating device to a temperature suitable for blow molding. During this time, preforms that are injection molded and transported cannot be heated to the appropriate blow molding temperature and must be discarded (stopping the injection molding device requires even more time to restart). Also, the amount of preforms that are discarded is greater for blow molding machines with high productivity (e.g., 1.5-step machines). Generally, in order to mass-produce containers with stable quality, it is necessary to heat the preforms under predetermined heating conditions in the same way so that they always have the same temperature distribution. The range of these predetermined heating conditions is usually narrow, and the temperature of the structures that make up the heating device (frame, reflector, etc.) also has an effect. Therefore, in order to raise and adjust the temperature of the heating device again so that the specified heating conditions can be achieved, it is necessary to appropriately raise the temperature of the heating device's structure and adjust the ambient temperature back to within the specified range.

[0056] The control method for the blow molding apparatus 1 in the above embodiment monitors the temperature of the air (atmosphere) inside the heating device, compares the target value of the atmosphere temperature with the measured value, and changes the heating capacity (heater output) and cooling capacity (blower output) of the heating device according to the temperature difference. When the temperature difference is large (for example, -10°C: the measured value is 10°C lower than the target value), the heating capacity is increased and the cooling capacity is decreased, and when the temperature difference is small (for example, -2°C), the heating capacity is decreased and the cooling capacity is increased. As a result, the atmosphere can be heated and adjusted to the target value quickly (the heating device can be started up quickly), and the preform 10 can be heated to the blowing temperature quickly. As a result, the amount of preform that is discarded can be reduced.

[0057] Furthermore, the control method for the blow molding apparatus 1 of this embodiment allows for optimal adjustment of heating and cooling capacity by setting the heating capacity increase rate (heater output increase rate) and cooling capacity decrease rate (blower output decrease rate) according to the temperature difference for each predetermined region of the heating apparatus (Zone 1, Zone 2, Zone 3, etc.).

[0058] Furthermore, the control method of the blow molding apparatus 1 in this embodiment allows for slowing down the transport of the preform 10 within the blow molding apparatus 1 by appropriately extending the molding cycle while the atmosphere is being heated and adjusted. Alternatively, injection molding may be performed once in multiple predetermined cycles, resulting in a longer cycle time. This further reduces the amount of preform waste.

[0059] Here, with reference to Figures 9, 10, and 11, the heating device cooling mechanism (cooling device for the heating device) of the heating section 360 of the blow molding apparatus 1 according to a specific embodiment will be described. Figure 9 is a diagram showing the internal configuration of the heater box 800 provided in the heating section 360 of a specific embodiment. Figure 10 is a diagram showing the external configuration of the heater box 800 provided in the heating section 360 of a specific embodiment. Figure 11 is a diagram showing the piping for introducing cooling air into the heater box 800.

[0060] The heater box 800 is equipped with a heating device inside. The heating device consists of, for example, a quartz heater (heating element, heating lamp) and a reflector (reflector). In this example, the quartz heater and reflector are positioned to sandwich the preform 10 as it is transported along the transport section 300 (the quartz heater and reflector are not shown in Figures 9 and 10).

[0061] In addition to the blower mentioned above, the heater box 800 is provided with a pipe 810 that supplies cooling air to cool the reflector. The pipe 810 has a plurality of nozzles 812 that blow cooling air inward into the heater box 800. The nozzles 812 are provided at approximately equal intervals along the entire length of the pipe 810. The nozzles 812 are located behind the reflector (not shown in the figure). The reflector is cooled from the back by the cooling air blown out from the nozzles 812. On the outside of the heater box 800, the pipe 810 has a plurality of connection parts 814 for connecting piping for introducing cooling air. Three connection parts 814 are shown in Figure 10, and they are provided to correspond to each of the three divided regions of the heater box 800. At least the same number of connection parts 814 as the divided regions of the heater box 800 are provided on the outside of the heater box 800.

[0062] The piping (pneumatic circuit) shown in Figure 11 includes a heater box 800, an accumulator 820, a first pneumatic source 830, and a second pneumatic source 840. The accumulator 820 is connected to the first pneumatic source 830 via a first flow control valve 850 and a first solenoid valve 860, and stores pressurized gas (compressed air) supplied from the first pneumatic source 830. The first solenoid valve 860 is a normally closed solenoid valve. As a result, when the first solenoid valve 860 is energized, the accumulator 820 opens to receive and store pressurized air from the first air pressure source 830, and when the first solenoid valve 860 is not energized, it automatically closes to prevent the stored air from being exhausted to the first air pressure source 830 (in the event of a power outage, pressurized air is not supplied to the accumulator 820). The first air pressure source 830 and the second air pressure source 840 supply gas pressurized to, for example, 1.2 to 2.0 MPa into the pipeline. The accumulator 820 stores, for example, 0.2 to 0.5 L of pressurized gas.

[0063] The heater box 800 is connected to the second air pressure source 840 via a pilot-operated valve (third solenoid valve) 870. Specifically, cooling air (pressurized gas) is supplied from the second air pressure source 840 to each connection point 814 of the pipe 810 provided in the heater box 800.

[0064] The pilot-operated valve 870 is a normally closed valve. The pilot-operated valve 870 is connected to the accumulator 820 via a second solenoid valve 880. The piping extending from the second solenoid valve 880 to the pilot-operated valve 870 branches into two, one connected to the pilot-operated valve 870 and the other connected to the second flow control valve 890. Alternatively, the second flow control valve 890 may be installed in the middle of the piping extending from the second solenoid valve 880 to the pilot-operated valve 870. The second solenoid valve 880 is a normally open solenoid valve. As a result, the accumulator 820 automatically opens to supply air to the pilot-operated valve 870 when the second solenoid valve 880 is not energized, and closes to stop supplying air to the pilot-operated valve 870 when the second solenoid valve 880 is energized. The second flow control valve 890 controls the flow rate of air supplied from the accumulator 820 to the pilot-operated valve 870.

[0065] When air is supplied from the accumulator 820 to the pilot-operated valve 870, the pilot-operated valve 870 opens, and cooling air is introduced from the second air pressure source 840 to the heater box 800. This cooling air is then blown out from the nozzle 812 inside the heater box 800 onto the back of the reflector. As a result, the reflector is cooled.

[0066] The cooling mechanism described above is particularly effective during power outages. The operation of the cooling mechanism during a power outage will be explained below. First, when power is supplied, the first solenoid valve 860 is opened to store a predetermined volume of pressurized gas in the accumulator 820 in advance (the first solenoid valve 860 may be closed after storage is complete). If the blow molding apparatus 1 is not powered due to a power outage, the first solenoid valve 860 automatically closes, and the second solenoid valve 880 automatically opens. As a result, the air stored in the accumulator 820 is supplied to the pilot-operated valve 870, and the pilot-operated valve 870 automatically switches from a closed state to an open state. As a result, the pressurized gas from the second air pressure source 840 is automatically supplied to the pipeline and ejected from the nozzle 812 of the pipe 810 to the back of the reflector as cooling air. Furthermore, the second flow control valve 890 controls the flow rate of air supplied from the accumulator 820 to the pilot-operated valve 870, allowing the pilot-operated valve 870 to remain open for a predetermined time, thus enabling the cooling of the reflector inside the heater box 800 for a predetermined time during a power outage.

[0067] During a power outage, the blower ceases to function, causing the ambient temperature inside the heater box 800 to rise significantly due to the residual heat of the reflector. If the preform becomes abnormally heated by the high-temperature atmosphere, it may tip over or melt, coming into contact with the quartz heater, potentially leading to damage to the heating device or a fire. The cooling mechanism described above can prevent these malfunctions by automatically cooling the reflector with air during a power outage. Furthermore, after a predetermined time has elapsed, the air supply from the accumulator 820 stops, and the pilot-operated valve 870 automatically closes, automatically stopping the supply of cooling air from the second air pressure source 840. This prevents the compressed air stored in the second air pressure source 840, which may consist of a compressor or similar device, from being depleted during a power outage, allowing the remaining compressed air to be effectively used during startup. In addition, since each valve in the pipeline can be switched without power, an expensive uninterruptible power supply (UPS) is not required.

[0068] Furthermore, the present invention is not limited to the embodiments described above, and can be freely modified and improved as appropriate. In addition, the material, shape, dimensions, numerical values, form, number, and placement of each component in the embodiments described above are arbitrary and not limited as long as they can achieve the present invention.

[0069] For example, in the above embodiment, a configuration in which various functional units are implemented in the processor of one device was described, but a configuration in which various functional units are implemented distributed across the processors of multiple devices via a local network or the internet is also possible. Furthermore, in the above embodiment, the display unit 710 and the input unit 720 were described in separate configurations, but they may be configured as a single functional unit that can be input and displayed via a touch panel or the like.

[0070] This application is based on Japanese patent applications filed on 17 July 2020 (JP 2020-123156) and on 2 September 2020 (JP 2020-147627), which are incorporated herein by reference in their entirety. All references incorporated herein are incorporated as a whole. [Explanation of symbols]

[0071] 1: Blow molding apparatus, 10: Preform, 20: Container, 100: Injection molding section, 200: First inversion section, 300: Conveying section, 310: First conveying member, 360: Heating section, 400: Second inversion section, 500: Blow molding section, 600: Control device, 612: Target value acquisition section, 614: Measured value acquisition section, 616: Calculation section, 618: Adjustment section, 620: Cycle time control section, 700: Input / output device

Claims

1. A control method for a manufacturing apparatus that blow-moldes a preform to produce a resin container, A step of obtaining a target temperature in a heating device that heats the preform to a suitable temperature for blow molding, A step of obtaining the actual temperature inside the heating device detected by a sensor placed inside the heating device, A step of calculating the temperature difference between the target value and the measured value, A step of adjusting the heating capacity and cooling capacity of the heating device based on the temperature difference, A method for controlling a manufacturing apparatus, including the control of the apparatus.

2. A method for controlling a manufacturing apparatus according to claim 1, comprising the step of adjusting the heating capacity and cooling capacity of each predetermined region in a plurality of divided predetermined regions of the heating apparatus.

3. The manufacturing apparatus has an injection molding section for injection molding a preform, A method for controlling a manufacturing apparatus according to claim 1 or 2, wherein the cycle time in the injection molding section is extended until the temperature inside the heating device reaches a target value.

4. An injection molding process in which a bottomed resin preform is injection molded, A method for manufacturing a resin container, comprising: a blow molding step, in which a preform molded in the injection molding step is blow-molded to manufacture a resin container, A method for manufacturing a resin container, comprising implementing the control method of the manufacturing apparatus described in any one of claims 1 to 3 in order to heat the preform molded in the injection molding step to a suitable temperature for blow molding.

5. A control device for a manufacturing apparatus that blow-moldes a preform to produce a resin container, A target value acquisition unit that acquires a target temperature in a heating device that heats the preform to an appropriate temperature for blow molding, A unit for acquiring actual values ​​of the temperature inside the heating device, which is detected by a sensor placed inside the heating device, A calculation unit that calculates the temperature difference between the target value and the measured value, An adjustment unit that adjusts the heating capacity and cooling capacity of the heating device based on the temperature difference, Control devices for manufacturing equipment, including those mentioned above.

6. The control device for a manufacturing apparatus according to claim 5, further comprising a divided adjustment unit for adjusting the heating capacity and cooling capacity of each predetermined region in a plurality of divided predetermined regions of the heating apparatus.

7. The manufacturing apparatus has an injection molding section for injection molding a preform, A control device for a manufacturing apparatus according to claim 5 or 6, which controls the manufacturing apparatus to extend the cycle time in the injection molding section until the temperature inside the heating device reaches a target value.

8. An injection molding section for injection molding a resin preform with a bottom, A heating section including a heating device for heating the preform to a suitable temperature for blow molding, A blow molding section for manufacturing a resin container by blow molding a preform heated in the aforementioned heating section, A control device for a manufacturing apparatus according to any one of claims 5 to 7, A manufacturing apparatus for resin containers having the following properties.

9. The apparatus for manufacturing a resin container according to claim 8, comprising a display unit configured to display the target value and the measured value.

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