JPH065861Y2 - Temperature controller for heating cylinder of injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a temperature control device for a heating cylinder in an injection molding machine.

(Prior Art) Conventionally, the temperature control of the heating cylinder 11 is usually plural (3 in the figure).
2), the front temperature control area 12, the central temperature control area 13, and the rear temperature control area 14 from the left side as shown in FIG.
In addition, there is a nozzle part temperature control region 15 for the nozzle 20 at the front end. These temperature control zones 12 to 15
Are both provided with a band heater and a thermocouple (both not shown), and these are both connected to the temperature controllers 16 to 19 and receive a signal from the thermocouple to thereby provide a nozzle and a band heater, The heating cylinder is controlled to the set temperature. ON for control operation of these temperature controllers 16 to 19
There are various methods such as -OFF control, proportional control, PI control, and PID control, but all of them are designed to maintain equilibrium after the temperature reaches a set value.

Further, in addition to the temperature controllers 16 to 19, a temperature controller 21 for keeping the temperature set at a temperature lower by about 50 ° C. than these set temperatures is provided as shown in FIG. The heat retention temperature controller 21 may be any of the temperature control regions 12 to 15, but for example, a thermocouple 22 provided in the nozzle temperature control region 15 is provided with a changeover switch 23.
Connected through. Therefore, the changeover switch 23 includes a nozzle part temperature controller 16 and a thermocouple 22, a front part temperature controller 17 and its thermocouple 24, a central part temperature controller 18 and its thermocouple 25,
The rear temperature controller 19 and the thermocouple 26 thereof are opened and closed, and the relay 27 is opened and closed. Relay 27 controls its A contacts 28 to 31 and its B contacts 32 to 35. Also, each temperature controller 16 to 19 has a B contact 32, respectively.
The electromagnetic switches 36 to 39 are connected via the switches 35 to 35. The electromagnetic switches 36 to 39 control opening / closing of the nozzle heater 40, the front heater 41, the central heater 42, and the rear heater 43.

At the time of normal molding, the changeover switch 23 is in the upper position (opened state) as shown in FIG.
22 is open to the temperature controller 21 and thermocouple 22
24 to 26 are connected to the respective temperature controllers 16 to 19. Also, since relay 27 is not working,
The contacts 28 to 31 are opened and the electromagnetic switches 36 to 39 are independent, and the B contacts 32 to 35 are closed to the electromagnetic switches.
Since 36 to 39 are connected to the respective temperature controllers 16 to 19, the heaters 40 to 43 shown in FIG. 4 are individually controlled and heated to a predetermined temperature. The heater 40 is for the nozzle 20 and 41 is the front temperature control region 12
It is for. Further, 42 is for the central temperature control region 13 and 43 is for the rear temperature control region 14.

When the changeover switch 23 is placed in the lower position (closed state) due to the operation stop of the injection molding machine or the like, the thermocouple 22 of the nozzle part is connected to the heat retention temperature controller 21, and the thermocouples 22 to 24 or
26 opens for each temperature controller 16-19. At the same time, the B contacts 32 to 35 are opened, the electromagnetic switches 36 to 39 are opened to the respective temperature controllers 16 to 19, and the A contacts 28 to 31 are closed so that the electromagnetic switches 36 to 39 are in series. It is connected to the heat retention temperature controller 21. As a result, the heaters 40 to 41 are heated by the heat retention temperature controller 21 to a low temperature which is about 50 ° C. lower than that of the nozzle portion or the like.

(Problems to be solved by the invention) Since the conventional device switches to the heat insulation circuit manually because it is a manual switch, it is simple and low in cost, but it does not require automatic operation because it is not automatic. When switching is forgotten, the resin in the cylinder thermally accumulates and is thermally decomposed, causing defective phenomena such as burning and the generation of carbides in the molded product, and resulting in loss of thermal energy and no effect. Further, since all the thermocouple inputs other than the thermocouple input of the heat insulation circuit are cut by the changeover switch, there is a problem that the actual temperature cannot be displayed and the actual temperatures of the other three zones cannot be known.

(Means for Solving Problems) The present invention has been proposed in order to solve the above-mentioned drawbacks of the prior art, and a plurality of temperature controllers for controlling the temperature of the heating cylinder and the nozzle portion and the same temperature controller are provided. The same number of thermocouples that supply temperature signals, a temperature controller that receives a temperature signal from one of the thermocouples and that has a preset temperature lower than the temperature controller, and a timer that operates by an injection molding machine operation stop signal And a relay that connects the heat retention controller and the heater in series by a time-out signal of the same timer, and connects the one thermocouple to either the one temperature controller or the heat retention temperature controller, and injects During operation of the molding machine, the temperature of the heating cylinder and the nozzle portion are controlled by the plurality of temperature controllers, and when the operation is stopped, the same temperature control temperature is controlled by the temperature control temperature controller. The temperature of the heating cylinder and the nozzle portion, in which the thermocouple input of the node is taken in, is controlled, and the actual temperature of the heating cylinder portion can be displayed. It is a means.

(Function) By setting the heat retention start time in advance with the new timer, the heat retention circuit when the molding machine is stopped automatically and effectively functions, and the actual temperature display of all cylinder heater zones is also possible.

(Embodiment) Hereinafter, the present invention will be described with reference to the embodiments of the drawings. FIGS. 1 and 2 show an embodiment of the present invention, and reference numerals 16 to 19 and 21 to
Since the members 22, 24 to 39 are the same as those of the conventional one shown in FIG. 3, their detailed description will be omitted. In addition, in FIG. 1, the changeover switch 23 of FIG. 3 is deleted, and the thermocouple input section of the temperature keeping circuit is
The A contact 54 of the relay 27 is inserted. Also the temperature controller 16
B input 55 of relay 27 is inserted to the input of thermocouple 22 of the above, and other thermocouples 24 to 26 are connected to temperature controller 17 to
Connect to each 19 directly. As a result, it is possible to display the actual temperature during the heat retention in the heat retention circuit zone.

Next, the difference between FIG. 1 and FIG. 3 will be explained.
Is a B contact point during motor operation. Generally, when the molding machine is temporarily stopped, the rotation of the motor (power sources for mold opening / closing, injection, and plasticization, which are the basic operations of the injection molding machine) is stopped, and the heating cylinder temperature control circuit. Since it is turned on only, the B contact is used during motor operation to automatically switch to the heat retention circuit as a trigger signal for the heat retention start timer. That is, when the motor rotation is stopped, the motor is closed. 52 is a heat retention start timer, which is a timer for presetting the pause time of the molding machine, and the set time is free. It is possible to automatically cancel the heat retention circuit and switch to the normal temperature circuit by starting the motor operation.

53 is a time-out time limit contact of the heat retention start timer, which controls the heat retention circuit and the switching relay 27 of the normal molding circuit. The contacts are timed on and momentarily off.
Reference numeral 54 denotes an A contact of the relay 27, which regulates the start timing of the heat insulation circuit operation and at the same time, takes in only the thermocouple input at the time of heat insulation temperature control and displays the heat insulation temperature of the nozzle 20. 55 is relay 27
The B contact point regulates the operation start timing of the temperature control circuit during normal molding and, at the same time, displays the temperature of the nozzle 20 during normal molding.

Next, the operation of the above-described embodiment will be described.

During normal molding, the motor is in an operating state, and the B contact 51 in FIG. 1 is in an open state, so the heat retention start timer 52 is not excited and therefore the relay 27 is not excited either, and the A contact 54 of the relay 27 is also opened. Due to this condition, the thermocouple 22 of the nozzle 20 is open to the heat retention temperature controller 21, and the thermocouples 22 and 24 to 26 are connected to the respective temperature controllers 16 to 19. Further, since the relay 27 is not operating, the A contacts 28 to 31 are opened and the respective electromagnetic switches 36 to 39 are independent, and the B contacts 32 to 35 are closed and the respective electromagnetic switches 36 to 39 are respectively closed. Since they are connected to the temperature controllers 16 to 19, the heaters 40 to 43 shown in FIG. 4 are individually controlled and heated to a predetermined temperature.

With the operation stop of the injection molding machine, the B contact 51 is changed from the open state to the closed state, and the heat retention start timer 52 is automatically timed for the preset molding machine pause time, and the time-out signal causes the time-out time limit contact 53 to be set. Closed,
Energize relay 27. The thermocouple 22 of the nozzle 20 is a relay 27
The A contact 54 of the above is automatically connected to the heat retention temperature controller 21, and the temperature controller 16 of the nozzle 20 is opened by the B contact 55 of the relay 27. Switch to the circuit.

Thermocouples 24-26 are directly connected to temperature controllers 17-19. The B contacts 32 to 35 of the relay 27 are opened, the electromagnetic switches 36 to 39 are opened to the respective temperature controllers 16 to 19, and the A contacts 28 to 31 are closed to the electromagnetic switches 36 to 39. Are connected in series to the heat retention temperature controller 21. As a result, the heaters 40 to 43 are kept warm by the temperature controller 21.
Is heated to a low temperature of, for example, about 50 ° C. lower than that of the nozzle portion 20 and the like, and thermocouple inputs 22 and 24 to 26 are connected to temperature controllers 21 and 17 to 19 so that the respective temperature control is performed. The actual temperature of the area can also be displayed. The temperature controllers 16 to 19 are disclosed in JP-A-60-242029.
It is also possible to employ the two-stage setting type temperature controller disclosed in the publication.

Next, referring to FIG. 2, the nozzle temperature control region 15
In the front, center, and rear temperature control regions 12, 13, and 14, there is a large difference in the heat capacity of the pair to be heated. It is impossible to control this in one temperature control area and display the actual temperature due to the difference in heat capacity. As in the present invention, the control is performed with a thermocouple input in one temperature control area for all four temperature control areas, and the actual temperature can be displayed simultaneously for all four temperature control areas. It is possible to cover the unreasonable temperature control function due to the difference in heat capacity.

(Effect of the Invention) As described in detail above, the temperature control device for the heating cylinder of the injection molding machine according to the present invention uses the conventional manual switch to switch the temperature control circuit to the temperature control circuit and the four control areas during the temperature control. For the temperature control device that displays the actual temperature with a single warming temperature controller, a warming start timer that uses the B contact as a trigger during motor operation is provided to automatically switch to the warming circuit and Since the temperature in the control area can be displayed, the cost is low, and the resin in the heating cylinder does not become high temperature by simple operation, and it has the advantages that good quality molded products can be obtained during the subsequent operation. .

[Brief description of drawings]

FIG. 1 is a heater wiring diagram of a device showing an embodiment of the present invention, FIG. 2 is a wiring diagram of an embodiment of the present invention, FIG. 3 is a heater wiring diagram of a conventional device, and FIG. 4 is a conventional wiring diagram. Here is an example. Explanation of main parts of the figure 11 …… Heating cylinder 20 …… Nozzle 16 to 19 …… Temperature controller 11 …… Insulation temperature controller 22, 24 to 26 …… Thermocouple 27 …… Relay 51 …… Motor running B Contact 52 …… Heat retention start timer 53 …… Time-out of heat retention start timer Time-limited contact 54 …… A contact of relay 27 (signal during warming) 55 …… B contact of relay 27 (signal during normal molding)

Claims (1)

[Scope of utility model registration request] 1. A plurality of temperature regulators for controlling the temperature of a heating cylinder and a nozzle portion, a number of thermocouples for supplying temperature signals to the temperature regulators, and a temperature signal from one of the thermocouples. Along with the temperature control temperature control that is set to a lower temperature than the temperature control, a timer that operates by the injection molding machine operation stop signal, and a relay that connects the temperature control controller and the heater in series by the time-out signal of the timer. , The one thermocouple is connected to either the one temperature controller or the heat retention temperature controller, and the temperature of the heating cylinder and the nozzle portion is controlled by the plurality of temperature controllers during operation of the injection molding machine. When the operation is stopped, the temperature of the heating cylinder and the nozzle section, which receives the thermocouple input of the heat retention temperature controller, is controlled by the heat retention temperature controller. And, and the temperature controller of the injection molding machine heating cylinder, characterized in that allowed the actual temperature display of the heating cylinder.