Blow molding apparatus and blow molding method

Abstract

To provide a blow molding device that can suppress a decrease in production efficiency.SOLUTION: A blow molding device 2 includes: a pressure sensor 2245 that can measure the pressure of a blow fluid supplied into a molding object at predetermined measurement time intervals; and a pressure monitoring unit 2301 that monitors whether an abnormality occurs in the pressure of the blow fluid on the basis of pressure values measured by the pressure sensor 2245 in a blow molding process. In a first period during the execution period of blow molding, the pressure monitoring unit 2301 monitors the pressure measurement values at monitoring time intervals shorter than the monitoring time intervals for pressure measurement values in a second period different from the first period.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a blow molding apparatus and a blow molding method.

Background Art

[0002] Conventionally, in a blow molding apparatus that performs blow molding processing to form a molded body from a molded object (such as a preform or a parison) using a mold, the pressure of the blow fluid supplied into the molded object has been monitored. For example, Patent Document 1 discloses that in a blow molding apparatus equipped with a blowing pressure detection sensor, if the blowing pressure inside the molded object does not reach the set value even after sufficient time has elapsed for the blowing pressure inside the molded object to reach the set value, it is regarded that some abnormality has occurred on the blowing side, and a warning to that effect is given.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In blow molding processing, when monitoring the occurrence of an abnormality based on the pressure of the blow fluid detected by a pressure sensor, it is effective in suppressing the subsequent stop of the blow molding apparatus or shortening the stop time of the blow molding apparatus to quickly detect the occurrence of an abnormality or signs of the occurrence of an abnormality. However, as disclosed in Patent Document 1, if it is assumed that the occurrence of an abnormality is detected after waiting for sufficient time to elapse after the blowing of the blow fluid, during that time For example, if a burst occurs inside the mold, the burst can cause the molded material to scatter. The degree of this increases. As a result, the removal process required for the device user to remove the fragments of the molded product from the mold becomes more difficult. Due to operational reasons, the blow molding equipment had to be shut down, leading to a decrease in production efficiency.

[0005] In view of the above problems, the present invention provides a blow molding method that can suppress the decrease in production efficiency. The objective is to provide an apparatus and a blow molding method. [Means for solving the problem]

[0006] To achieve the above objective, a blow molding apparatus according to one aspect of the present invention is provided. Blow molding is a process in which blow fluid is supplied into a molded body that is held between molds to form a hollow molded body. A blow molding apparatus that performs molding, The pressure of the blow fluid supplied into the molded body can be measured at predetermined measurement time intervals. Pressure measuring unit, In the blow molding process, based on the pressure measurement value measured by the pressure measuring unit The system includes a pressure monitoring unit that monitors whether or not an abnormal pressure has occurred in the blow-off fluid. The aforementioned pressure monitoring unit is When it is the first period of the execution period of the blow molding process, it is different from the first period. The pressure measurement values ​​in the second period are measured at a monitoring time interval shorter than the monitoring time interval. Monitor the measured values. [Effects of the Invention]

[0007] According to one aspect of the blow molding apparatus of the present invention, the pressure monitoring unit is used in the blow molding process. When monitoring whether or not a pressure anomaly has occurred in the blow-off fluid based on pressure measurements, If it is the first period of the molding process, then in the second period which is different from the first period Monitor the pressure measurement values at monitoring time intervals shorter than the monitoring time intervals of the pressure measurement values. Therefore , during the execution period of the blow molding process, for example, a period in which a serious pressure abnormality occurs that causes defective products of the molded body or causes the blow molding device to stop or malfunction is defined as the first period , and pressure abnormalities can be monitored at a monitoring time interval shorter than that of other periods (the second period). . Therefore, in the blow molding process, by quickly detecting the occurrence of pressure abnormalities or signs of the occurrence of pressure abnormalities , it is possible to suppress a decrease in production efficiency.

[0008] Other problems, configurations, and effects will be clarified in the form for implementing the invention described later.

Brief Description of the Drawings

[0009] [Figure 1] It is an overall configuration diagram showing an example of the container molding system 1. [Figure 2] It is a schematic plan view showing an example of the blow molding device 2. [Figure 3] It is a schematic configuration diagram showing an example of the molding unit 22. [Figure 4] It is a block diagram showing an example of the blow molding device 2. [Figure 5] It is a graph showing changes in pressure measurement values in the blow molding process. [Figure 6] It is a diagram showing an example of the pressure monitoring setting screen 5 for setting the operating conditions of pressure monitoring. [Figure 7] It is a diagram showing an example of the operation of the ejection process.

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments for implementing the present invention will be described with reference to the drawings. In the following ​This section schematically illustrates the scope necessary to explain the objectives of the present invention, and explains the relevant parts of the present invention. This explanation will primarily focus on the necessary details, and any parts that are omitted will be explained using publicly available technology. It shall be considered as such.

[0011] (Configuration of container molding system 1) Figure 1 is a schematic diagram showing an example of a container molding system 1. The container molding system 1 is a mold. Using 20, it functions as a production system that produces hollow molded bodies 4 by blow molding. In this embodiment, polyethylene terephthalate (P) is produced by biaxial stretch blow molding. From a preform 3, which is a form of molded body made from ET) as a raw material, a hollow molded body 4 is produced. This explanation will focus primarily on the production of a container (PET bottle) as a single form.

[0012] The container molding system 1 consists of an injection molding machine 10 and a pre-formed molding machine as its main components. A preform removal device 11, a preform transport conveyor 12, a preform supply device 13, and A rolling machine 2, a molded body removal device 14, a molded body conveyor 15, and a discarding conveyor 1 It is equipped with 6.

[0013] In the container molding system 1, the raw material, synthetic resin, is fed into the injection molding device 10. Then, the preform 3 is molded by the injection molding machine 10. The preform 3 is preform The preforms are removed from the injection molding machine 10 by the preform removal device 11 and transported to the preform conveyor 1 It is then transferred to 2 and heated to a predetermined temperature while flowing along the preform conveyor belt 12. Then, the preform 3 is sequentially supplied to the blow molding machine 2 by the preform supply device 13. Then, the preform 3 is molded into a molded body 4 (PET bottle) by the blow molding machine 2. The molded body 4 is removed from the blow molding apparatus 2 by the molded body removal device 14. The molded body is transferred to the molded body conveyor 15, and as it flows along the molded body conveyor 15, for example, A device for attaching shrink film and labels to the molded body 4, and a device for filling the molded body 4 with beverages. The product is then transported to subsequent processes such as a filling device and a crimping device that crimps the lid onto the molded body 4.

[0014] When the molded body 4 is formed from the preform 3 by the blow molding apparatus 2, for example, When a pressure anomaly such as a burst is detected, the system that detected the pressure anomaly Feature 4 is an output line that delivers a normal molded body 4 to a subsequent process (in the example in Figure 1, a molded body transport line). Instead of being transferred to the conveyor belt 15, the molded body is transferred to the discard conveyor belt 16 by the molded body removal device 14. It will be sent.

[0015] Figure 2 is a schematic plan view showing an example of a blow molding apparatus 2. Figure 3 shows the molding unit 22 This is a schematic diagram showing an example of the configuration. The blow molding apparatus 2 consists of multiple (12 in this embodiment) Using the mold 20, blow fluid is supplied into the preform 3 which is held in the mold 20. The blow molding process to form a hollow molded body 4 is repeated for each mold 20. In terms of form, the blow fluid is described as air, but any other fluid is also possible. It can be a gas or a liquid.

[0016] The blow molding apparatus 2 has a rotary unit 21 and a rotary as its main components. Multiple (12 in this embodiment) units arranged at predetermined intervals on the circumferential orbit of unit 21 The system includes a molding unit 22 and a control unit 23 that controls various parts of the blow molding apparatus 2.

[0017] The rotary unit 21 is formed, for example, in a disc shape and supports a plurality of molding units 22. A rotary support unit 210, and a rotary support unit 210 that rotates at a predetermined rotational speed (rotational period). It includes a rotating mechanism 211 for turning.

[0018] Each of the multiple molding units 22 has a mold support mechanism 22 that supports the mold 20 so that it can be opened and closed. 0 and a seal support part 221 that supports the preform 3, which is held in the mold 20, in a sealed state. , a stretch rod 2 is inserted into the preform 3 which is supported by the seal support portion 221. 22 and a stretch rod support mechanism that supports the stretch rod 222 so that it can move forward and backward. 223 and a blower that supplies or discharges blow fluid (air) to the stretch rod 222. It includes a low fluid supply and discharge section 224 and a temperature control mechanism section 225 for adjusting the temperature of the mold 20.

[0019] The blow fluid supply and discharge section 224 is in contact with the stretch rod 222 via the seal support section 221. The main pipe 2240 is connected, and three branch pipes 2241A~ are branched from the main pipe 2240. It is provided in 2241C and in branch piping 2241A connected to a low-pressure pre-blow air supply source. A pre-blow valve 2242 and a branch pipe 2 connected to the high-pressure main blow air supply source. The main blow valve 2243 located in 241B and the branch pipe 2 connected to the exhaust system An exhaust valve 2244 provided in 241C and the main piping 2240 or seal support part 221 It is equipped with a pressure sensor 2245. The pressure sensor 2245 is located within the preform 3. The pressure of the supplied blow fluid (pre-blow air, main blow air, blow air exhaust) It functions as a pressure measuring unit capable of measuring at predetermined measurement time intervals, and the measurement results are recorded at each point in time. Outputs the pressure measurement value.

[0020] Note that in Figures 2 and 3, the rotating mechanism 211, the mold support mechanism 220, and the seal support 2 The specific configuration of 21 and the stretch rod support mechanism 223 is omitted, but for example, Modules for generating driving force such as servo motors and cylinders, linear guides, and ball screws. Drive force transmission mechanisms such as gears, cams, belts, couplings, and bearings, and linear sensors, etc. It is configured by appropriately combining sensors such as an NCOR sensor and a limit sensor. Figures 2 and 3 omit the specific configuration of the temperature control mechanism 225, but for example, electric heater It is composed of a combination of temperature control modules such as a thermometer and sensors such as a temperature sensor. ru.

[0021] Figure 4 is a block diagram showing an example of a blow molding apparatus 2. The control unit 23 is a blow molding apparatus. The modules and sensors provided by the Tali unit 21 and the multiple molding units 22 and the electrical It is connected to and comprehensively controls the rotary unit 21 and the multiple molding units 22. It functions as a control unit. Figure 4 shows a pre-blow valve as part of a module group. 2242, the main blow valve 2243 and the exhaust valve 2244, and as part of the sensor group The pressure sensor 2245 is shown in the diagram, but the other module groups and sensor groups are omitted from the diagram. It's an abbreviation.

[0022] The control unit 23 consists of, for example, a general-purpose or dedicated computer. The main components of unit 23 are a control unit 230, a communication unit 231, and an input unit 232 It also includes an output unit 233 and a storage unit 234.

[0023] The control unit 230, for example, controls the arithmetic processing unit (CPU, MPU, GPU, etc.) and It is composed of a sequencer. The control unit 230, for example, stores blown components stored in the storage unit 234. By executing the molding program 2340, the blow molding control unit 2300 and the pressure monitoring unit 2 It functions as 301 and the rejection control unit 2302. Details of each part 2300~2302 will be provided later. To state.

[0024] The communication unit 231 is connected to a communication network, for example, the device user of the blow molding apparatus 2. Terminal equipment (not shown) used by operators and managers, etc., and production of container molding system 1 A communication interface for sending and receiving various data with the production control device (not shown) that performs the management. It functions as a control. The input unit 232 is used for various input operations by the user of the blow molding apparatus 2. In addition to receiving the signal, the output unit 233 communicates via the display screen, signal tower illumination, and buzzer sound. By outputting various information to the device user, it functions as a user interface. .

[0025] The memory unit 234 stores various programs (operator) used in the operation of the blow molding apparatus 2. (Operating system (OS), blow molding program 2340, etc.) and data (device setting information 2) Stores (341 etc.). Device setting information 2341 indicates that the blow molding device 2 performs the blow molding process. This is information that allows you to register various operating conditions when executing an action, for example, the display screen (settings interface) It is configured to be editable by the device user via a (face).

[0026] (Regarding the blow molding control step by the blow molding control unit 2300) The blow molding control unit 2300 includes a rotary unit 21 and a plurality of molding units 22. The measured values ​​and detected values ​​of the sensor group are acquired, and the rotary unit 21 and multiple molding units The modules provided by 22 are operated, and the preform supply device 13 is used to supply preforms. The supply operation of Form 3 and the removal operation of the molded body 4 by the molded body removal device 14 are to be coordinated. Then, the blow molding process is repeated for every 20 molds.

[0027] The blow molding process is carried out by multiple units supported by the rotary support portion 210 of the rotary unit 21. Each of the molds 20 (molding units 22) rotates 360° along a circular orbit by the rotating mechanism 211. During the blow molding cycle (1 cycle) which rotates (1 revolution), as shown in Figure 2, (S1 (S2) Set preform 3, (S3) Close operation of mold 20, (S4) Stretch, (S4) (S5) Start of pre-blow air supply, (S6) Start of main blow air supply, Main blow pressure (S7) Force maintenance, (S8) Start of blow air exhaust, (S8) Opening operation of mold 20, (S9) Molded body 4 The process is executed in the order of retrieval.

[0028] In the blow molding process, the blow molding control unit 2300, in (S1), The preform 3 supplied from the base 2 is supported in a fixed state by the seal support part 221. In (S2), the mold support mechanism 220 closes the mold 20, and in (S3), The preform 3 is extended by moving the stretch rod 222 forward. (S4) The pre-blow valve 2242 opens to start supplying pre-blow air, and (S5) Then, while extending the stretch rod 222, the closing operation of the pre-blow valve 2242 and The main blow air supply is initiated by opening the main blow valve 2243. The low pressure is increased to the target pressure value, and the supply of the main blow air is continued in (S6). By doing so, the blow pressure is maintained at the pressure target value, and in (S7), the main blow valve 2243 The blow-up fluid is discharged by the closing operation of the valve and the opening operation of the exhaust valve 2244, thereby reducing the blow-up pressure. Lower it. (S8) While moving the stretch rod 222 outwards, the mold support The mechanism 220 opens the mold 20, and in (S9), the seal support 221 The fixed position of the molded body 4 is released, and the molded body 4 is removed from the seal support portion 221. Oh, in the blow molding process described above, the start timing (start angle) of each operation (S1~S9) The timing of the end (end angle) can be changed as appropriate, and other actions can be added. stomach.

[0029] Furthermore, the blow molding control unit 2300 monitors the pressure rise period using the pressure monitoring unit 2301 (details are as follows). When a pressure anomaly is detected in the molded body 4 (actually the molded body 4 in the process of being molded), (as described later), The supply of blow fluid to the molded body 4 is stopped. This prevents the molded body 4 from bursting. Even if it is suppressed in advance, or if a burst occurs in the molded body 4, the burst will not affect the molded body This can reduce the degree of scattering of the 4.

[0030] (Regarding the pressure monitoring step by the pressure monitoring unit 2301) The pressure monitoring unit 2301, in the blow molding process described above, receives a pressure sensor 2245. Based on the measured pressure values, monitor whether or not a pressure anomaly has occurred in the blow-off fluid. In this embodiment, the blow molding process is performed by multiple molding units 22 to form multiple metal Since this is performed sequentially for type 20, the pressure monitoring unit 2301 performs the above-mentioned pressure monitoring. This process is performed for each mold 20, and the mold 20 in which a pressure anomaly is detected among the multiple molds 20 is identified as a pressure anomaly. This is identified as mold 20a.

[0031] Figure 5 is a graph showing the change in pressure measurements during the blow molding process. Figure 5 shows the horizontal axis. The rotation angle (time) of the rotary support part 210 is shown on the graph, with pressure on the vertical axis, and the normal pressure is shown on the graph. Force curve P1 (solid line), pressure curve P2 (dashed line) when pressure abnormality occurs due to burst, pressure Monitoring tolerance lower limit curve P3 (dashed line), pressure lower limit value at each monitoring point for pressure monitoring. This diagram illustrates the upward-pointing triangle and the upper pressure limit (downward-pointing triangle).

[0032] Pressure curves P1 and P2 are shown when the blow molding control unit 2300 performs the blow molding process. In other words, by starting the supply of blow fluid (pre-blow air, main blow air) The pressure rise period (S4) to (S5) during which the blowdown pressure is increased to the target pressure value, and the blowdown fluid The pressure maintenance period (S6) is during which the blow pressure is maintained at the target pressure value by continuing to supply the blow pressure, and Pressure reduction period: The pressure is reduced by stopping the supply of low fluid and discharging blow fluid. This is obtained when steps S7) and S7 are performed in order. Note that the pressure rise period is determined by the pre-blow air. The first pressure rise period due to supply, and the second pressure rise period due to the supply of main blow air. This period includes at least a second pressure increase period.

[0033] At that time, the pressure monitoring unit 2301 is in the first period of the blow molding process execution period. This refers to a monitoring time shorter than the monitoring time interval for pressure measurements in the second period, which is different from the first period. The pressure measurement is monitored at intervals. In other words, the pressure monitoring unit 2301 monitors the actual blow molding process. During the production period, for example, defective molded products 4 may be produced, or the blow molding machine 2 may stop or malfunction. The period during which serious pressure anomalies (such as bursts) that could cause damage occur is designated as Period 1. Pressure anomalies are monitored at shorter monitoring intervals than in other periods (second period). Monitoring interval This may be set at regular time intervals (periods) during the first or second period. And, they may be set at different time intervals. This can be obtained, for example, by dividing the first period by the number of monitoring points included in that first period. The average time interval is obtained by dividing the second period by the number of monitoring points included in that second period. It is set to be shorter than the average time interval.

[0034] In this embodiment, the pressure monitoring unit 2301 detects a serious pressure anomaly during the pressure rise period. In order to detect the occurrence of a burst, if the first period is a pressure rise period, then the second Shorter than the monitoring time interval for pressure measurements during the pressure maintenance period and the pressure decrease period. The pressure measurement value is monitored at regular monitoring time intervals. For example, the pressure monitoring unit 2301 monitors the pressure rise period. In between, at least one of the pressure measurements at each monitoring time set by the monitoring time interval is If the pressure falls outside the set tolerance range for each monitoring point, a pressure anomaly occurs. It detects the pressure tolerance range, which is at least one of the lower and upper limits of the pressure measurement. This sets out the limits, and at least an acceptable lower limit is set during the pressure rise period.

[0035] Furthermore, the pressure monitoring unit 2301 has the following operating conditions when performing pressure monitoring: monitoring time interval and The display screen (setting interface) shows at least one of the monitoring points and the pressure tolerance range. It is configured to be configurable via, for example, as part of the device setting information 2341, in the storage unit 234. It will be remembered.

[0036] Figure 6 shows an example of the pressure monitoring settings screen 5, where the operating conditions for pressure monitoring are set. The force monitoring settings screen 5 includes, for example, a list-format input window 50 and a setting button 51. The input window 50 corresponds to the time point in time when monitoring the pressure measurement. The rotation angle and the pressure tolerance range (lower pressure limit and upper pressure limit) for that rotation angle are given as 1 Multiple sets of rotation angles and pressure tolerances can be input as a set.

[0037] Figure 6 shows the pressure for monitoring time points No. 2 to 6 as the setting value for input window 50. Each has a lower limit set, and the pressure lower limit and pressure upper limit are set for monitoring time points No. 1, 7, and 8. The diagram shows the case where limits are set, and each setting value in the input window 50 is shown in Figure 5. Each of the triangles shown on the graph corresponds to a specific point. The input window 50 allows you to set the monitoring time. However, instead of setting a monitoring time point, it may be possible to set a monitoring time interval. Also, input Wi The number of sets of rotation angle and pressure tolerance ranges (number of columns in input window 50) can be increased or decreased. Noh theater is also acceptable.

[0038] The pressure monitoring unit 2301 is set to the ideal pressure when the blow molding process was performed successfully in the past. Pressure monitoring is performed according to the pressure curve (for example, stored as historical data in the memory unit 234). The operating conditions may be set. For example, the pressure tolerance range at each monitoring point is the ideal pressure range. The blow pressure at each monitoring point in the blowdown is either subtracted from a predetermined allowable value or multiplied by an allowable percentage value. Based on the tolerance lower limit curve P3 (see Figure 5) generated by this process, the setting is determined. That would be good.

[0039] Furthermore, the operating conditions for pressure monitoring can be set via the pressure monitoring setting screen 5 or the allowable lower limit curve P3. When determined, the monitoring points are six points during the pressure rise period, pressure maintenance period, and pressure fall period. The above (more preferably 8 points or more) are set, and during the pressure rise period, 0. Three or more points that satisfy a monitoring time interval of 0.08 seconds or less (more preferably 0.05 seconds or less) Preferably, five or more points are set. Therefore, the pressure monitoring setting screen 5 is The operating conditions for pressure monitoring include six or more sets (more preferably eight or more sets) of rotation angles (during monitoring). It is preferable that the point and pressure tolerance range be configurable.

[0040] (Regarding the exclusion control step by the exclusion control unit 2302) The rejection control unit 2302 identifies the mold 20a where a pressure abnormality has occurred, based on the pressure monitoring unit 2301. When this occurs, blow molding is performed using multiple molds 20, including the mold 20a in question. This process is repeated for each mold 20, and the pressure difference is discharged from the discharge line that discharges the molded body 4. The molded body 4 (hereinafter referred to as "rejected molded body 4a") formed by the normally generated mold 20a is rejected. The exclusion process is repeated.

[0041] Figure 7 shows an example of the operation of the rejection process. In Figure 7, the pressure monitoring unit 2301 Of the 12 molds 20, the "5th" mold 20 was identified as the mold 20a where a pressure anomaly occurred. Let me explain the cases in which this can happen.

[0042] When performing the rejection process of the rejection molded body 4a, the rejection control unit 2302 performs, for example, rejection molding When body 4a is removed from the pressure abnormality mold 20a by the mold body removal device 14, A rejection instruction is sent to the shape removal device 14. Upon receiving the rejection instruction, the molded body removal device 14 The discarded molded body 4a is not on the molded body transport conveyor 15 (discharge line), but on the discarded conveyor 1 Transferred to line 6 (exclusion line).

[0043] Furthermore, the rejection control unit 2302 outputs notification information indicating that the rejection process has been initiated. The notification information includes, for example, the mold number indicating the pressure abnormality in mold 20a (as shown in the example in Figure 7). This includes "5"). The output destination for the notification information is, for example, output unit 233 (display screen, etc. (The Gunal Tower lights up and a buzzer sounds), or a terminal device capable of communicating via the communication unit 231 ( (Not shown) The terminal device may be, for example, a portable or stationary device used by the device user. It is made up of computers.

[0044] Furthermore, the rejection control unit 2302 checks whether the termination condition for the rejection process has been met during the execution of the rejection process. The system monitors whether or not a pressure anomaly has occurred, and when it detects that the termination condition has been met, it de-identifies the mold that caused the pressure anomaly. At the same time, the execution of the rejection process is terminated. The rejection control unit 2302, for example, the input unit 232 and When the device user sends an input command via the terminal device to indicate the termination of the exclusion process, The system detects when the conditions for ending the rejection process have been met. Furthermore, a molded body inspection device (failure to complete the rejection process) is installed on the rejection conveyor 16. If a (illustrated) is installed, the rejection control unit 2302 will determine the molded body inspection device If a normal test result is received as a result of the inspection of item 4, the rejection process will be terminated. The condition may be detected as met. The rejection control unit 2302 may also perform rejection processing a predetermined number of times. If this occurs, the fulfillment of the termination condition for the exclusion process may be detected. A predetermined number of times, the display screen (settings This may be the number of times set by the device user via a fixed interface, or the number of times the device has been used in the past. The number of times the user has given input to terminate the exclusion process may also be used.

[0045] As described above, according to the blow molding apparatus 2 and blow molding method of this embodiment, pressure The monitoring unit 2301 monitors the pressure measured by the pressure sensor 2245 during the blow molding process. When monitoring whether or not an abnormal pressure has occurred in the blow-molding fluid based on the measured values, blow molding process If it is the first period of the execution period, pressure measurement in the second period, which is different from the first period. The pressure measurement is monitored at a shorter monitoring time interval than the value monitoring time interval. Therefore, blow During the molding process, for example, if a defective product of the molded body 4 is generated, or if the blow molding apparatus The period during which serious pressure anomalies occur that could lead to shutdowns or failures is defined as the first period. Pressure anomalies can be monitored at shorter monitoring intervals than in other periods (the second period). Therefore, in blow molding processes, the occurrence of pressure abnormalities or signs of pressure abnormalities must be detected quickly. By doing so, the decline in production efficiency can be suppressed.

[0046] (Other embodiments) The present invention is not limited to the embodiments described above, and will proceed within the scope of the spirit of the invention. It is possible to implement various modifications within the system. And all of these are based on the technical ideas of the present invention. It is included in the idea.

[0047] In the above embodiment, the blow molding apparatus 2 comprises a plurality of rotary molding units 22. Although we have explained the case where this is possible, blow molding is performed using multiple molds 20 for each mold 20. If it is a repetitive process, it may be applied to a blow molding apparatus configured in a different manner. This may be applied to a blow molding apparatus that performs blow molding using one mold 20.

[0048] In the above embodiment, the blow molding apparatus 2 performs a blow molding process in one form of the molded object. We have described the case in which a biaxial stretch blow molding method is performed on a certain preform 3, Direct blow molding may also be performed on other forms of the shape, such as hollow parisons. Alternatively, other blow molding methods may be used. Also, the blow molding apparatus 2 is a hot parsing machine. The N method (also called the one-stage method) and the cold Parison method (also called the two-stage method) It is also acceptable to adopt this option.

[0049] In the above embodiment, the material of the molded body (preform 3) is polyethylene terephthalate. I explained the case of PET, but there are other types as well, such as polypropylene (PP) and PO Other thermoplastic resins such as ethylene naphthalate (PEN) may be used, and recycled resins may also be used. Materials may be used. Furthermore, the molded body (preform 3) can be molded in ways other than injection molding, for example, It may have any shape formed by any molding method such as PCM molding, or a single layer structure Either a single-layer or multi-layer structure may be adopted. [Explanation of Symbols]

[0050] 1...Container molding system, 2...Blow molding machine, 3...Preform (workpiece), 4...Molded body, 4a...Rejection molded body, 5...Pressure monitoring setting screen 10...Injection molding device, 11...Preform removal device, 12…Preform conveyor, 13…Molded product conveyor, 14…Molded body removal device, 15…Molded body conveyor, 16…Rejection conveyor, 20...Mold, 20a...Mold with abnormal pressure occurrence, 21...Rotary unit, 22...Molding unit, 23...Control unit, 210...Rotary support part, 211...Rotation mechanism part, 213...Stretch rod, 220...Mold support mechanism, 221...Seal support, 222...Stretch rod, 223...Stretch rod support mechanism, 224...Blow fluid supply and discharge section, 225...Temperature control mechanism section, 230...Control unit, 231...Communication unit, 232...Input unit, 233...Output unit, 234...Storage unit, 2240...Main piping, 2241A~2241C...Branch piping, 2242... Pre-blow valve, 2243... Main blow valve, 2244... Exhaust valve, 2245... Pressure sensor, 2300...Blow molding control unit, 2301...Pressure monitoring unit, 2302...Rejection control unit, 2340...Blow molding program, 2341...Device setting information

Claims

1. A blow molding apparatus that performs blow molding, which involves supplying blow fluid into a molded body held between molds to form a hollow molded body, A pressure measuring unit capable of measuring the pressure of the blow fluid supplied into the molded body at predetermined measurement time intervals, In the blow molding process, a pressure monitoring unit monitors whether or not an abnormal pressure has occurred in the blow fluid based on the pressure measurement value measured by the pressure measuring unit, The blow molding control unit controls the blow molding process by sequentially progressing through a first pressure rise period by supplying pre-blow air and a second pressure rise period by supplying main blow air, which are pressure rise periods in which the pressure is raised to a target pressure value by starting the supply of the blow fluid; a pressure maintenance period in which the pressure is maintained at the target pressure value by continuing the supply of the blow fluid; and a pressure decrease period in which the pressure is lowered by stopping the supply of the blow fluid and discharging the blow fluid. The aforementioned pressure monitoring unit is During the pressure rise period, the pressure maintenance period, and the pressure fall period, the system monitors whether or not the pressure abnormality has occurred based on the pressure measurement values. During the second pressure rise period, the pressure measurement values ​​are monitored at a shorter monitoring time interval than the monitoring time interval for the pressure measurement values ​​during the first pressure rise period, the pressure maintenance period, and the pressure fall period. The blow molding control unit is When the pressure monitoring unit detects the occurrence of the pressure abnormality during the pressure rise period, the supply of the blowdown fluid is stopped. Blow molding machine.

2. The aforementioned pressure monitoring unit is During the pressure rise period, if at least one of the pressure measurements at each monitoring time set by the monitoring time interval falls outside the pressure tolerance range set for each monitoring time, the occurrence of the pressure abnormality is detected. The blow molding apparatus according to claim 1.

3. The aforementioned monitoring time is, During the pressure rise period, the pressure maintenance period, and the pressure fall period, six or more points are set, During the aforementioned pressure rise period, three or more points are set that satisfy the aforementioned monitoring time interval of 0.08 seconds or less. The blow molding apparatus according to claim 2.

4. The aforementioned pressure monitoring unit is The monitoring time interval or the monitoring time point and the pressure tolerance range are configured to be configurable via a setting interface. The blow molding apparatus according to claim 2 or claim 3.

5. A blow molding method is a blow molding process in which a blow fluid is supplied into a molded body held between molds to form a hollow molded body, In the blow molding process, a pressure monitoring step is performed to monitor whether or not an abnormal pressure has occurred in the blow fluid supplied to the molded body, based on pressure measurements taken by a pressure measuring unit capable of measuring the pressure of the blow fluid at predetermined measurement time intervals. The blow molding control step controls the blow molding process by sequentially progressing through a first pressure rise period by supplying pre-blow air and a second pressure rise period by supplying main blow air, which are pressure rise periods in which the pressure is raised to a target pressure value by starting the supply of the blow fluid; a pressure maintenance period in which the pressure is maintained at the target pressure value by continuing the supply of the blow fluid; and a pressure decrease period in which the pressure is lowered by stopping the supply of the blow fluid and discharging the blow fluid. The pressure monitoring step is, During the pressure rise period, the pressure maintenance period, and the pressure fall period, the system monitors whether or not the pressure abnormality has occurred based on the pressure measurement values. During the second pressure rise period, the pressure measurement values ​​are monitored at a shorter monitoring time interval than the monitoring time interval for the pressure measurement values ​​during the first pressure rise period, the pressure maintenance period, and the pressure fall period. The blow molding control step described above is: When the pressure monitoring step detects the occurrence of the pressure abnormality during the pressure rise period, the supply of the blow-off fluid is stopped. Blow molding method.

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