JP4249857B2 - Resin drying method and resin drying apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention is used for drying resin such as resin pellets before resin molding.Resin drying method andThe present invention relates to a resin drying apparatus.
[0002]
[Prior art]
Conventionally, when moisture is contained in resin pellets, which are molding materials for resin molding, the moisture is vaporized by heating at the time of molding, and the quality of molded products is deteriorated and defective products are generated. Therefore, the drying process is performed to the resin pellet which should be supplied to an injection molding machine before shaping | molding. Although this drying treatment is based on heating, if the heating temperature exceeds 100 ° C., which is the evaporation temperature of moisture, there may be inconveniences such as color change in the resin pellets. For this reason, conventionally, in the drying treatment of resin pellets, the resin pellets are placed under a certain reduced pressure and heated to prevent deterioration such as color tone change.
[0003]
A vacuum pump is used for the decompression means and a heater is used for the heating means for the decompression and drying treatment of the resin, and the decompression treatment and the heat treatment are performed by placing the resin to be dried in the treatment tank. Air pressure by a blower is used as a conveying means for replenishing the resin to the treatment tank, discharging the dried resin, and supplying the resin to the molding machine.
[0004]
[Problems to be solved by the invention]
By the way, in order to obtain a molded product of good quality, it is necessary to coordinate the resin molding and resin drying. When an abnormality occurs on the resin drying process side and the operation stops, the molding material to the molding machine side The supply of a certain resin is stopped. In the injection molding machine, when the molding operation is stopped, if the residence time of a large amount of molten resin staying in the injection nozzle becomes long, a failure such as discoloration occurs depending on the resin material. Also, cleaning operations such as disassembling the injection nozzle to remove discolored resin are troublesome.
[0005]
  Therefore, the present invention avoids the stoppage of resin discharge as much as possible to prevent the influence on subsequent processing such as molding processing.Resin drying method andAn object is to provide a resin drying apparatus.
[0006]
[Means for Solving the Problems]
The resin drying apparatus of the present invention includes resin (resin pellet 2) drying processing means (drying tank 4, heaters 60 and 64, heat pipe 62, vacuum pump 70), resin discharging means (discharge port 82, opening and closing plate 88, 90, storage tank 8), resin supply means (pellet tank 6, supply pipe 14, blower 18, suction pipe 20) and control means (control device 200, control calculation unit 202, touch panel switch 204), and resin drying process The resin discharge and resin replenishment control operations are executed, control anomalies are detected, and the resin discharge operation enables the resin to be discharged from the drying processing means regardless of the dry state as much as possible. It is possible to prevent inconvenience due to the stop of resin supply for subsequent processing of the molding machine (10) and the like.
[0007]
  The resin drying of the present invention according to claim 1The method is a resin drying method in which the resin to be supplied to the injection molding machine is dried and the dry resin is supplied to the injection molding machine side, the resin is supplied to the drying processing tank, and the drying processing tank is heated in a reduced pressure state. A drying treatment step of drying the resin, a resin supply step of supplying the resin dried from the drying treatment tank to the injection molding machine, and a resin supply step of replenishing the resin to be dried into the drying treatment tank; , Decompression of the drying treatment tank and its release, heating, supply of the resin from the drying treatment tank to the injection molding machine, replenishment of the resin to the drying treatment tank, etc. Detecting and detecting the control abnormality, selecting either operation stop or operation continuation, and supplying the resin from the drying treatment tank to the injection molding machine when the operation is continued, and the drying treatment tank Fat supplementation abnormal, if the drying tank of the vacuum abnormality, and a step of continuing the supply operation of the resin into the injection molding machine from said drying tankIt is characterized by that.
[0008]
  That is, resin dryingIn the wayComprises a resin drying processing means, a resin discharging means for discharging the dried resin from the drying processing means, and a resin replenishing means for supplying the resin to be dried to the drying processing means. The dried resin is discharged from the resin discharging means and supplied. By executing the control operation for replenishing the resin and detecting the control abnormality to prevent the occurrence of an accident, the resin can be discharged from the drying means as much as possible regardless of the dry state. By continuously supplying the resin to the subsequent processing, it is possible to avoid the influence on the subsequent processing such as depletion of the resin.
[0009]
  The resin drying apparatus of the present invention according to claim 2 dries the resin (resin pellet 2) to be supplied to the injection molding machine (10)., Supplying dry resin to the injection molding machineA resin drying apparatus, which is a drying tank (4) that heats and drys the resin under reduced pressure, and a resin supply means (storage tank) that supplies the resin dried from the drying tank to the injection molding machine. 8, blower 18, air supply pipe 26, supply pipe 112, intake pipe 114) and resin supply means (pellet tank 6, supply pipe 14, blower 18, suction pipe) for supplying the resin to be dried into the drying treatment tank. 20) and performing control operations such as decompression and release of the drying treatment tank, heating, supply of the resin from the drying treatment tank to the injection molding machine, and replenishment of the resin to the drying treatment tank. A control error is detected,When that control abnormality is detected,Select either operation stop or operation continuation.When the operation is continued, the resin is supplied from the drying treatment tank to the injection molding machine.In the case of abnormality in replenishment of the resin to the drying treatment tank and abnormal pressure reduction of the drying treatment tank, the operation of supplying the resin from the drying treatment tank to the injection molding machine is continued.Control means (control device 200, control arithmetic unit 202, touch panel switch 204)RuIt is characterized by that.
[0010]
  That is, even if an abnormality occurs in the resin drying apparatus, the resin can be supplied to the injection molding machine depending on the content or degree. For example, when a dry defect occurs, if a poorly dried resin is molded, even if a defective product occurs, the reduction in work efficiency and the degree of damage can be reduced compared to stopping the injection molding machine. Therefore, the control abnormality is detected, and either the operation stop or the operation continuation is selected according to the control abnormality. In the case of the operation continuation, if the resin is supplied from the drying treatment tank to the injection molding machine, the injection molding machine is The inconvenience of stopping can be prevented. That is, by continuing the molding operation of the injection molding machine, there is no inconvenience that the molten resin stays in the injection nozzle and stops, and resin discoloration and cleaning of the injection nozzle can be avoided, resulting in a decrease in production efficiency. Can be prevented. In addition, it becomes possible to return to a normal operation | movement by restoring the location of control abnormality during resin supply.
  Even if the pressure in the drying tank is poor, the drying process can be continued by heating the resin. As a result, the resin can be continuously supplied to the injection molding machine and the injection molding machine is stopped. Can prevent inconvenience.
[0012]
  Claim3The resin drying apparatus of the present invention according toInThe control unit is configured to supply or stop the supply of the resin to the injection molding machine when detecting a pressure reduction abnormality in the drying treatment tank. That is, when an abnormality in pressure reduction occurs in the drying treatment tank, the heating temperature of the resin rises, and depending on the resin, discoloration may occur. Therefore, in the event that a decompression abnormality occurs in the drying treatment tank, it is possible to select whether to supply or stop the dried resin to the injection molding machine at the operator's discretion, and prevent deterioration of the quality of the molded product Can do.
[0013]
  Claim4The resin drying apparatus of the present invention according toThe control means includes:The control operation is stopped when an abnormal heating of the resin is detected. That is, the abnormal heating of the resin in the drying tank is either overheating or low temperature that does not reach the specified temperature. In the case of such a heating abnormality, the quality of the product is remarkably deteriorated. For example, in a lens molded product, the product accuracy and quality are affected. Therefore, the control operation is stopped and the resin supply is restricted. In other cases, contamination of the molten resin in the injection nozzle of the injection molding machine can be minimized and the amount of resin to be discarded can be minimized without stopping the resin supply.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
[0015]
  FIG. 1 illustrates the present invention.Resin drying method andOne embodiment of the resin drying apparatus is shown, and FIGS. 2 and 3 show the configuration of the lower part of the drying treatment tank. This resin drying apparatus guides resin pellets 2 as a resin to be dried from a pellet tank 6 to a drying processing tank 4 as a drying processing means, discharges the resin pellets 2 after drying, and discharges them from a storage tank 8 to an injection molding machine 10. Supply to the side.
[0016]
A hopper 12 as a replenishing tank for storing the resin pellets 2 to be replenished to the drying treatment tank 4 is provided on the upper part of the drying treatment tank 4 for storing the resin pellets 2 to be dried. The hopper 12 is connected to the pellet tank 6 via a supply pipe 14, and a suction unit 16 for sucking outside air is provided in the middle of the supply pipe 14. The hopper 12 is connected to a blower 18 serving as an air supply / intake unit via a suction pipe 20. An opening / closing valve 22 and a filter 24 are provided in the middle of the suction pipe 20, and an air supply pipe 26 is provided on the exhaust side of the blower 18. The exhaust pipe 28 and the opening / closing valves 30 and 32 are provided. That is, the pellet tank 6 and the blower 18 constitute a resin replenishing means for replenishing the resin pellet 2 to the drying treatment tank 4. Therefore, if the on-off valve 30 is closed, the on-off valves 22 and 32 are opened to form a ventilation path, and the blower 18 is driven to make the inside of the hopper 12 have a negative pressure, air flows into the supply pipe 14 through the aspirator 16. The resin pellet 2 is sucked from the pellet tank 6 and loaded into the hopper 12. Arrows a, b, and c indicate the air flow, and d indicates the resin pellet 2 and the air flow.
[0017]
An opening / closing mechanism 34 is provided below the hopper 12, and the resin pellet 2 is supplied to the drying treatment tank 4 in accordance with the opening / closing of the opening / closing mechanism 34. The opening / closing mechanism 34 includes an opening / closing plate 38 using the air cylinder 36 as a driving means, and the movement of the opening / closing plate 38 blocks or opens the hopper 12 and the connecting cylinder 40 via the opening / closing mechanism 34. At the time of blocking, the opening / closing plate 38 of the opening / closing mechanism 34 seals the upper side of the drying treatment tank 4, and a structure for sealing is not shown, but an O-ring, packing, or the like is used. An arrow e indicates the moving direction of the opening / closing plate 38. The movement of the opening / closing plate 38 is detected by proximity sensors 42 and 44 as opening / closing detection means. The connecting cylinder 40 is a supporting means for supporting the hopper 12 to the drying treatment tank 4 via the opening / closing mechanism 34, and a proximity sensor 46 is provided on the peripheral surface as a means for detecting the resin pellet 2.
[0018]
The drying treatment tank 4 has a cylindrical shape with a conical bottom surface in order to guide the resin pellet 2 downward, and includes an inner tank 50 inside the exterior body 48. In the inner tank 50, as a means for uniformly dispersing the resin pellets 2 to be replenished in the drying treatment tank 4, the first stratifier 52 and the resin pellets 2 fall from only the central portion of the drying treatment tank 4 and the surroundings In order to prevent the inconvenience that the portion remains, a second stratifier 54 is provided as a means for uniformly holding the resin pellet 2 in the drying treatment tank 4. Each of the stratifiers 52 and 54 is connected in the vertical direction, and a temperature sensor 58 is attached to the peripheral surface portion of the connecting cylinder 56. In the inner tank 50, a plurality of heaters 60 and heat pipes 62 are installed as heating means in the drying processing means for the resin pellets 2, and the heater 64 as the heating means in the drying processing means is provided on the outer surface of the inner tank 50. Temperature sensors 66 and 68 for detecting the wall surface temperature are installed on the inner wall surface of the tank 50. Further, the outer surface portions of the respective stratifiers 52 and 54 constitute a heat conducting surface.
[0019]
A vacuum pump 70 is connected to the inner tank 50 through a vent pipe 72 as a pressure reducing means in the drying processing means. The vent pipe 72 is provided with a filter 74 and a pressure switch 76. The pressure switch 76 monitors the depressurized state in the drying treatment tank 4 and generates a switch output indicating the depressurized state when shifting to a predetermined depressurized state. An arrow f indicates the discharge of air during decompression. A vacuum breaker valve 78 is connected to the inner tank 50 via a vent pipe 80. When the vacuum breaker valve 78 is turned on, the drying treatment tank 4 returns to atmospheric pressure due to the inflow of outside air.
[0020]
A storage tank 8 is provided at a discharge port 82 as a discharge means of the drying treatment tank 4 via a connecting portion 84. As shown in FIGS. 2 and 3, the connecting portion 84 includes opening and closing plates 88 and 90 as first and second opening / closing means as resin discharging means for discharging the resin pellet 2 from the drying treatment tank 4. In addition, O-rings 87 and 89 are provided between the opening / closing support 85 and the inner wall portion of the connecting portion 84 to maintain airtightness.
[0021]
As shown in FIG. 2, the opening / closing support body 85 is formed with a notch recess 91 as a recess for opening the discharge port 82 to bite the resin pellet 2, and when the opening / closing plate 88 is closed. The end surface portion side hits the lower side of the notch recess 91, and the resin pellet 2 enters the inside of the notch recess 91, thereby preventing the fall.
[0022]
A space 92 is formed between the opening and closing plates 88 and 90 inside the opening and closing support 85. The opening / closing plate 88 uses the air cylinder 94 and the opening / closing plate 90 uses the air cylinder 96 as driving means to individually open and close the connecting portions 84. The movement of the opening / closing plate 88 is individually detected by the proximity sensors 98 and 100 as opening / closing detection means, and the movement of the opening / closing plate 90 is individually detected by the proximity sensors 102 and 104 as opening / closing detection means. An arrow g indicates opening / closing movement of the opening / closing plate 88, and h indicates opening / closing movement of the opening / closing plate 90. The space 92 formed between the opening and closing plates 88 and 90 is provided with a leak pipe 106 that leaks air to the inside. The leak pipe 106 is opened and closed by a leak valve 108, and the outside air inflow amount is adjusted. The inside of the drying treatment tank 4 can be adjusted to a predetermined pressure. Arrow i indicates the inflow of air.
[0023]
The opening / closing plate 88 constitutes a measuring means for setting the amount of the resin pellets 2 to be dropped depending on the opening time. Also, as shown in FIG. 3, the opening / closing plate 90 is dried through the connecting portion 84 when closed. The discharge port 82 of the tank 4 is sealed and functions as an airtight holding means. That is, the opening and closing plates 88 and 90 both have a function of opening and closing the discharge port 82, the former restricts the passage of the resin pellet 2 and the latter performs airtight holding, and shares the opening and closing function. .
[0024]
The storage tank 8 is connected to a hopper 110 on the injection molding machine 10 side via a supply pipe 112 and is connected to a blower 18 through an air supply pipe 26. That is, the blower 18 and the supply pipe 112 constitute a resin supply means for supplying the resin pellet 2 in the drying treatment tank 4 to the injection molding machine 10. The hopper 110 and the suction side of the blower 18 are connected through an intake pipe 114, and an open / close valve 116 is provided in the intake pipe 114. That is, by closing the on-off valves 22 and 32 and opening the on-off valves 30 and 116, a closed circuit is formed through the supply pipe 112 and the intake pipe 114, and when the blower 18 is driven, the resin pellets 2 dried from the storage tank 8 are dried. Is introduced into the hopper 110 and loaded. A resin tank 118 is provided below the hopper 110, and the resin pellets 2 are supplied from the hopper 110 to the resin tank 118 for resin molding. Arrows j and l indicate air, and arrow k indicates the resin pellet 2 and the flow of air. The resin tank 118 is provided with a proximity sensor 120 that is detection means for detecting the presence or absence of the resin pellet 2.
[0025]
Next, FIG. 4 has shown the control part of the resin drying apparatus. That is, the control unit controls the drying process of the drying process tank 4, the replenishment of the resin pellets 2 to the drying process tank 4, the supply of the resin pellets 2 from the drying process tank 4 to the injection molding machine 10, and the drying process. Abnormalities such as failure of the tank 4, the heater 60 as the drying processing means, the heat pipe 62 and the vacuum pump 70, the pellet tank 6 and the blower 18 as the resin replenishing means, the blower 18 and the supply pipe 112 as the resin supply means, etc. Generation, determination of operation stop or operation continuation corresponding to a predetermined operation abnormality, and control operation based on the determination are executed. The control unit is provided with a control device 200 as a control means using a microcomputer, and the control device 200 is provided with a control arithmetic unit 202 that performs a control operation. The control calculation unit 202 and the touch panel switch 204 are linked.
[0026]
The control arithmetic unit 202 includes a CPU 206, a TIMER 208 for measurement, a COUNTER 210, a RAM 212 for temporarily storing various control commands and calculation values, a ROM 214 for storing a control program for the CPU 206, setting data, various setting data, and an abnormality such as a failure. In addition, an EEPROM 216 or the like as a nonvolatile storage means for storing the location and the like is provided. Also provided are a plurality of input ports 218, 220, 226, 228 for receiving various sensor inputs and a plurality of output ports 230, 232, 234, 236, 238, 240, 242, 270 for sending drive outputs to the actuators. . That is, temperature sensors 58, 66, and 68 are connected to the input port 218 through the detection circuit 244. Proximity sensors 42, 44, 46, 98, 100, 102, 104, 120 are connected to the input port 220 through the detection circuit 246, and a pressure switch 76 is connected to the input port 226 through the detection circuit 252. Further, driving circuits 254, 256, 258, 260, 262, 264 are connected to the output ports 230, 232, 234, 236, 238, 240, respectively, and the vacuum pump 70, the blower 18, the heaters 60, 64, and the air cylinder are connected thereto. 36, 94, 96, open / close valves 22, 30, 32, 116, and vacuum breaker valve 78 are connected. A speaker 268 is connected to the output port 242 via an audio circuit 266 as a notification means.
[0027]
A touch panel switch 204 is connected to the input port 228 and the output port 270. The touch panel switch 204 hierarchically displays control command input, setting input, abnormality display, operation information, and the like as images. This is means for receiving an input position designated by an image as a switch. The touch panel switch 204 stores a CPU 272 that performs image hierarchical display, switch input position control, and the like, a RAM 274 that temporarily stores control data, an image memory 276 that includes an EEPROM that stores image data, a control program for the CPU 272, and setting data. ROM 278, input circuit 280, output circuit 282, liquid crystal drive circuit 284, and detection circuit 286. The liquid crystal drive circuit 284 has a display 288 as a display means for performing liquid crystal display, and the detection circuit 286 has a liquid crystal screen. Is connected to a switch 290.
[0028]
With the above configuration, the operation of the resin drying apparatus will be described.
[0029]
FIG. 5 is a flowchart showing the operation of this resin drying apparatus. When the operation of the control device 200 is started by the operation of the switch 290 of the touch panel switch 204, in step S1, the mode is shifted to the drying mode, the inside of the drying treatment tank 4 is depressurized, and heat drying is performed.
[0030]
In step S2, it is determined whether or not the resin pellet 2 replenishment mode is selected by the switch 290. When the resin replenishment mode is selected, the process proceeds to step S3 and the resin replenishment mode is executed. In step S4, it is determined whether or not the resin supply / replenishment mode is selected by the switch 290. When the resin supply / replenishment mode is selected, the process proceeds to step S5 to execute the resin supply / replenishment mode.
[0031]
In step S6, it is determined whether or not the resin supply mode is selected by the switch 290. When the resin supply mode is selected, the process proceeds to the resin supply mode in step S7. In step S8, it is determined whether or not the resin pellet 2 remains in the drying treatment tank 4. If there is no resin pellet 2, the operation is stopped.
[0032]
That is, the control operation of the resin drying apparatus includes a drying mode, a resin replenishment mode, a resin supply / replenishment mode, and a resin supply mode.
[0033]
The drying mode is a mode in which the resin pellets 2 filled in the drying treatment tank 4 are heated under reduced pressure and dried. That is, when the resin pellet 2 is loaded in the drying treatment tank 4, the vacuum pump 70 is driven to keep the drying treatment tank 4 in a reduced pressure state. That is, the opening and closing plate 88 is closed, the opening and closing plates 38 and 90 are closed to make the drying treatment tank 4 hermetically sealed, the vacuum pump 70 is operated to depressurize the inside of the drying treatment tank 4, and the resin pellets 2 are heated by the heaters 60 and 64. Is dried by heating. With the operation of the vacuum pump 70, outside air flows into the drying treatment tank 4 from the leak pipe 106, and the inside of the drying treatment tank 4 is maintained in a reduced pressure state of about 50 to 100 torr. The vapor generated from the resin pellet 2 is discharged to the outside as indicated by an arrow f along with the outside air flowing in from the leak pipe 106 by the suction of the vacuum pump 70. The evaporation temperature of water decreases in the drying treatment tank 4 due to the reduced pressure. Thereby, the heating temperature of the heaters 60 and 64 can be kept below a temperature at which the discoloration of the resin pellet 2 does not occur. The inside of the drying treatment tank 4 can be recovered to atmospheric pressure by stopping the vacuum pump 70 and operating the vacuum breaker valve 78.
[0034]
Next, the resin replenishment mode is a mode in which undried resin pellets 2 are loaded into the drying treatment tank 4. That is, in this control operation, the open / close plate 38 is opened, the open / close valves 30 and 116 are closed, and the open / close valves 22 and 32 are opened to form an air passage including the supply pipe 14, the suction pipe 20, and the exhaust pipe 28, By the operation of the blower 18, the resin pellet 2 is guided from the pellet tank 6 to the hopper 12 and supplied to the drying treatment tank 4. The blower 18 is operated until the proximity sensor 46 detects the resin pellet 2. When the resin pellet 2 is filled in the drying treatment tank 4, the opening / closing plate 38 is closed and vacuum drying is executed. Note that the blower 18 is intermittently operated several times every predetermined time, and if the proximity sensor 46 does not detect the resin pellet 2 even if the blower 18 is operated a predetermined number of times within the predetermined time, the pellet 18 It is determined that the inside of the tank 6 is empty, and an alarm sound is emitted from the speaker 268 as the determination output, or the fact is displayed on the display 288.
[0035]
Next, the resin supply / replenishment mode is a mode in which the resin pellets 2 dried in the drying treatment tank 4 are weighed and supplied to the injection molding machine 10, and the shortage resulting therefrom is replenished from the pellet tank 6 to the drying treatment tank 4. It is. When the proximity sensor 120 detects that the resin pellet 2 in the resin tank 118 has been consumed as the molding operation of the injection molding machine 10 proceeds, the inside of the drying treatment tank 4 is returned to atmospheric pressure, and the opening and closing plates 38 and 90 are opened. The opening / closing plate 88 is opened for a predetermined time, and the resin pellets 2 in the drying treatment tank 4 are freely dropped into the storage tank 8. The amount dropped into the storage tank 8, that is, the supply amount can be adjusted by changing the opening time of the opening and closing plate 88. Then, the on-off valves 22 and 32 are closed, the on-off valves 30 and 116 are opened to form an air circulation path of the air supply pipe 26, the supply pipe 112, and the intake pipe 114, and the blower 18 is operated for a predetermined time to store the tank by the air pressure. Eight resin pellets 2 are supplied to the resin tank 118. When the accumulation of the resin pellet 2 is not detected by the proximity sensor 120, the opening / closing plates 90 and 88 are opened again, and the blower 18 is operated so that the resin pellet 2 is supplied. Thereafter, the opening / closing plate 38 is opened, and the supply state is maintained until the proximity sensor 46 detects the resin pellet 2.
[0036]
Next, the resin supply mode is a mode in which the resin pellets 2 are supplied to the injection molding machine 10 until the resin pellets 2 in the drying treatment tank 4 disappear. This supply operation is as described above. Even if the resin pellet 2 is supplied a predetermined number of times within a predetermined time, if the proximity sensor 120 does not detect it, it is determined that the inside of the drying treatment tank 4 is empty, and the supply and drying operations are stopped.
[0037]
Next, an abnormality detection operation will be described. The following abnormality detection is performed in the control unit shown in FIG.
[0038]
a Abnormal detection of pressure switch 76
When the pressure switch 76 outputs a pressure reduction signal before the operation of the vacuum pump 70 is started, a message such as “abnormal pressure switch” is displayed or voiced to instruct the replacement of the pressure switch 76.
[0039]
b Detection of abnormal decompression
When the operation of the vacuum pump 70 is started and the pressure switch 76 does not reduce the pressure to a predetermined pressure after a predetermined time has elapsed, the vacuum pump 70 is stopped, the vacuum breaker valve 78 is operated, and the open / close plates 38, 88, 90 are several. After being opened and closed once, the vacuum pump 70 is operated again to start depressurization. When these operations are executed several times and the drying treatment tank 4 is not depressurized by the pressure switch 76, a message such as “vacuum abnormality” is displayed or voiced to notify the airtightness of the vacuum pump 70 or the open / close plates 38, 88, 90. Instructing replacement of packing, O-rings 87, 89, etc. for maintenance.
[0040]
c Detection of abnormalities in the open / close plates 38, 88, 90
When the air cylinders 36, 94, 96 are operated to open / close the open / close plates 38, 88, 90, and no signals are detected from the proximity sensors 42, 44, 98, 100, 102, 104, the corresponding open / close plates 38, 88 , 90 is opened and closed several times to determine whether an open / close detection signal is output. If the open / close detection signal is not obtained, “open / close plate (38) open error”, “open / close plate (38) close error”, “open / close plate (88) open error”, “open / close plate (88) close error” ”,“ Opening / closing plate (90) opening abnormality ”,“ opening / closing plate (90) opening abnormality ”, and the like are displayed or sounded.
[0041]
d Abnormality detection of heaters 60 and 64
If the temperature sensor 58, 66, 68 detects a temperature rise due to the heaters 60, 64 and the temperature rise is not confirmed even after a predetermined time has elapsed, a message such as “heater disconnection abnormality” is displayed or voiced.
[0042]
e Overheat abnormality detection
When the temperature rise due to heating of the heaters 60, 64 exceeds a predetermined temperature by the temperature sensors 58, 66, 68, a message such as “abnormal heater overheating” is displayed or voiced.
[0043]
f Temperature sensor 58, 66, 68 abnormality detection
By receiving the output values of the temperature sensors 58, 66 and 68, the detection circuit 244 monitors abnormalities such as disconnection. When disconnection of the temperature sensor 58, 66 or 68 is detected, a message such as “abnormality of the temperature sensor (58, 66 or 68)” is displayed or notified by voice.
[0044]
g Detection of resin supply abnormality
The opening and closing plates 88 and 90 are opened, the resin pellet 2 is supplied to the storage tank 8, the blower 18 is operated, and the output signal from the proximity sensor 120 is confirmed. When the output signal is not detected, the opening and closing of the opening and closing plates 88 and 90 and the blower 18 are operated several times. If the output signal is not detected, a message such as “resin supply abnormality” is displayed or voiced, and the blower 18 Abnormality or blockage of the air supply pipe 26, the supply pipe 112, the intake pipe 114, etc. is notified.
[0045]
Next, FIG. 6 shows a flowchart regarding the continuous control operation at the time of detecting an abnormality.
[0046]
This continuous control operation is executed in the resin supply and replenishment mode as an automatic operation. In step S11, an abnormality is detected during the automatic operation. In step S12, whether the detected abnormality is an abnormality in which the resin pellet 2 in the pellet tank 6 is emptied and the resin pellet 2 cannot be supplied to the drying treatment tank 4 is determined. Determine. In the case of an abnormality that cannot be replenished, the process proceeds to step S13, where an abnormality notification that prompts the pellet tank 6 to be filled with the resin pellet 2 is displayed on the display 288, or is notified by the sound of the speaker 268 through the audio circuit 266. After this notification, the process proceeds to the resin supply mode in step S14.
[0047]
If the abnormality cannot be replenished, the process proceeds to step S15, and it is determined whether or not the detected abnormality is an abnormality of the pressure switch 76. If the pressure switch 76 is abnormal, the process proceeds to step S16, where the abnormality notification is displayed on the display 288, or is notified by the sound of the speaker 268 through the audio circuit 266. After this notification, the process proceeds to the resin supply and replenishment mode in step S17.
[0048]
If the pressure switch 76 is not abnormal, the process proceeds to step S18 to determine whether or not there is a depressurization abnormality. If not, the process proceeds to step S19 and an abnormality notification is displayed on the display 288 or a sound. After notifying by the sound of the speaker 268 through the circuit 266, the process proceeds to step S20 to stop the operation. Here, abnormal locations such as the open / close plates 38 and 90, the heaters 60 and 64, the temperature sensors 58, 66 and 68, the blower 18 and the like are notified. If these abnormalities occur, the resin cannot be dried, or a fatal abnormality such as inability to supply the resin pellets 2 to the injection molding machine 10, the operation is immediately stopped in this case.
[0049]
If there is an abnormality in decompression, the process proceeds to step S21 to determine whether or not there is an operation continuation command at the time of abnormality. If there is an operation continuation command, the process proceeds to step S22 and an abnormality notification is displayed on the display 288. After the notification is given by the voice of the speaker 268 through the display or the audio circuit 266, the process proceeds to the resin supply and replenishment mode in step S23. Even if an airtight leak occurs due to failure of the vacuum pump 70 or damage to the packing, O-rings 87, 89, etc., it is determined that the drying treatment tank 4 is normally heated and the resin supply and replenishment mode is continued. That is, even if an abnormality in decompression occurs, the drying treatment tank 4 is heated by the heaters 60 and 64 and the drying process can be continued. Therefore, after the abnormality is notified, the resin supply and replenishment mode is continued.
[0050]
If there is no operation continuation command, the process proceeds to step S24, where an abnormality notification is displayed on the display 288, or is notified by the sound of the speaker 268 through the audio circuit 266, and then the process proceeds to step S25 to stop the operation. And
[0051]
In addition, although supply of the dry resin pellet with respect to an injection molding machine was demonstrated in embodiment, the resin drying apparatus of this invention can respond to various apparatuses which require supply of dry resin other than an injection molding machine. Yes, it is not limited to resin molding.
[0052]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
a Since the dried resin can be continuously supplied even at the time of abnormality, the subsequent processing requiring the supply of the resin can be continued without stopping.
b Since the dried resin can be continuously supplied even in the event of an abnormality, the molding operation of the injection molding machine can be continued, and the molten resin in the injection nozzle can be maintained in an appropriate flow state. Discoloration can be prevented.
c Since the user can select continuation or stop of the control operation in the event of an abnormality according to the resin material, discoloration of the resin material can be prevented or appropriate maintenance can be performed.
d In the case of an abnormality due to defective heating, the resin supply can be stopped to prevent the resin material from being expanded due to melt contamination with the undried resin.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a resin drying apparatus of the present invention.
FIG. 2 is a partially enlarged sectional view of the resin drying apparatus of the present invention.
FIG. 3 is a partially enlarged sectional view of the resin drying apparatus of the present invention.
FIG. 4 is a block diagram showing a control unit of the resin drying apparatus.
FIG. 5 is a flowchart showing the operation of the resin drying apparatus of the present invention.
FIG. 6 is a control flowchart related to operation continuation when an abnormality is detected in an embodiment of the resin drying apparatus of the present invention.
[Explanation of symbols]
2 Resin pellet 2
4 Drying treatment tank 4 (drying treatment means)
6 Pellet tank (resin supply means)
8 Reservoir (resin discharge means, resin supply means)
10 Injection molding machine
14 Supply pipe (Resin supply means)
18 Blower (resin supply means, resin replenishment means)
20 Suction tube (Resin supply means)
26 Air supply pipe (resin supply means)
60, 64 heater (drying means)
62 Heat pipe (drying treatment means)
70 Vacuum pump (drying means)
82 Discharge port (resin discharge means)
88, 90 Opening / closing plate (resin discharging means)
112 Supply pipe (resin supply means)
114 Intake pipe (resin supply means)
200 Control device (control means)
202 Control operation part (control means)
204 Touch panel switch (control means)

Claims (4)

A resin drying method for drying a resin to be supplied to an injection molding machine and supplying the dry resin to the injection molding machine side,
A drying process for supplying the resin to the drying tank and heating the drying tank under reduced pressure to dry it;
A resin supply step of supplying the resin dried from the drying treatment tank to the injection molding machine;
A resin replenishing step of replenishing the resin to be dried into the drying treatment tank;
Executes control operations such as decompression and release of the drying treatment tank, heating, supply of the resin from the drying treatment tank to the injection molding machine, replenishment of the resin to the drying treatment tank, and detection of control abnormality And, when detecting the control abnormality, selecting either operation stop or operation continuation, and supplying the resin from the drying treatment tank to the injection molding machine at the time of operation continuity;
In the case of abnormal replenishment of the resin to the drying treatment tank, abnormal pressure reduction of the drying treatment tank, a step of continuing the resin supply operation from the drying treatment tank to the injection molding machine,
A resin drying method comprising: A resin drying device for drying a resin to be supplied to an injection molding machine and supplying the dry resin to the injection molding machine side ,
A drying treatment tank for drying the resin by heating in a reduced pressure state;
Resin supply means for supplying the dried resin from the drying tank to the injection molding machine;
Resin replenishing means for replenishing the resin to be dried into the drying treatment tank;
Executes control operations such as decompression and release of the drying treatment tank, heating, supply of the resin from the drying treatment tank to the injection molding machine, replenishment of the resin to the drying treatment tank, and detection of control abnormality When the control abnormality is detected, either the operation stop or the operation continuation is selected, and when the operation is continued, the resin is supplied from the drying processing tank to the injection molding machine, and the resin is supplied to the drying processing tank. In the case of an abnormality, an abnormal pressure reduction of the drying treatment tank, a control means for continuing the operation of supplying the resin from the drying treatment tank to the injection molding machine ,
Resin drying device, characterized in that Ru comprising a.   3. The resin drying apparatus according to claim 2, wherein the control means supplies or stops the supply of the resin to the injection molding machine when detecting an abnormal pressure reduction in the drying treatment tank.   3. The resin drying apparatus according to claim 2, wherein the control means stops the control operation when detecting an abnormal heating of the resin.

Images