JPH0378046B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a hot plate used in a hot press device, etc., and more particularly to a hot plate using a sheathed heater, in which a heater element is disposed within a longitudinal tubular sheath, as a heat source. It is about improvement.

(Prior art and its problems) A hot plate is a plate having a heatable structure, and is used in a press machine or the like to heat a workpiece. For example, hot press equipment integrates laminates made by overlapping laminate materials such as resin-impregnated sheets, resin films or sheets, metal foils or plates, and produces laminate molded products such as electrical printed wiring boards and laminate boards. A plurality of hot plates are arranged between the fixed platen and the movable platen so that the laminate (workpiece) can be heated by the hot plates, and the laminate placed between the hot plates can be heated by the hot plates. By applying pressure based on the clamping action between the fixed platen and the movable platen while heating with the hot plate, the laminate can be integrated to produce a desired laminate molded product.

By the way, one type of such hot plates is a sheathed heater (cartridge heater) in which a heater element that generates heat when energized is disposed inside a longitudinal tubular sheath. There is a type of heat plate that is placed in the heater insertion hole and used as a heat source, but conventionally, in a hot plate that uses such a sheathed heater as a heat source, the sheathed heater has a structure in which only one heater element is inside. Because of this, it is difficult to accurately control the hot plate to the desired temperature distribution state, and in particular, it is difficult to uniformly heat the hot plate over its entire effective area. It was hot.

For example, in the hot press device described above, it is desirable to uniformly heat the hot plate to a predetermined target heating temperature over the entire effective area of the hot plate in order to improve the quality of the product. Simply controlling the energization in the same way for each sheathed heater (heater element) installed in the hole will result in differences in heating conditions and heat transfer conditions depending on each part of the hot plate, and the heater capacity of the heater element in the longitudinal direction of the sheathed heater. It is inevitable that the temperature (surface temperature) of the hot plate will vary due to variations or non-uniformity in the state of contact between the sheathed heater and the hot plate. Therefore, the effective surface of the hot plate is usually divided into a plurality of zones, and the sheathed heaters corresponding to each divided zone are controlled to be energized independently of each other. If the effective surface of the hot plate is divided into multiple zones and each zone is heated independently to the target heating temperature, the temperature variation within each zone will be smaller than the temperature variation of the entire hot plate. Since this is small, it is possible to reduce the variation in the temperature of the entire heating plate compared to the case where the sheathed heaters on the entire heating plate are controlled in the same way. It is possible to convert

However, in the conventional heating plate, as mentioned above, only one heater element is disposed in the sheathed heater, so in the arrangement direction of the sheathed heater, the heating plate can be heated independently of each other. Although the sheathed heater can be divided into a large number of controllable zones, it is not possible to divide the hot plate into such multiple zones in the longitudinal direction of the sheathed heater, and the sheathed heater has a length that roughly divides the hot plate in half. At most, it was possible to divide the hot plate into two zones by inserting and arranging the hot plate into the heater insertion hole from two directions. There were limits to achieving uniformity.

On the other hand, in parallel with such divisional control of the hot plate, the heater capacity of the heater element is adjusted in advance in the longitudinal direction of the sheathed heater so that the hot plate temperature in the longitudinal direction of the sheathed heater is uniform at the target heating temperature. However, in this case, it is necessary to use a sheathed heater with a heater capacity adjusted according to the target heating temperature each time the target heating temperature differs. There is a problem that requires it to be replaced.

(Solution) The present invention has been made against the background of the above, and is characterized in that a plurality of heater elements are arranged independently in the longitudinal direction within a longitudinal tubular sheath. The multi-circuit sheathed heaters arranged in series are respectively arranged in predetermined heater insertion holes formed in the hot plate, and each heater element of the multi-circuit sheathed heater is inserted into the hot plate. The reason is that each part can be heated individually.

(Function/Effect) According to such a hot plate, in the arrangement direction of the sheathed heater (multi-circuit sheathed heater), the hot plate can be divided into many zones whose temperature can be controlled independently from each other, just like the conventional hot plate. Not only can it be divided, but also in the longitudinal direction of the sheathed heater it is possible to divide the hot plate into a large number of zones whose temperature can be controlled independently of each other. In other words, according to the hot plate according to the present invention, when dividing the effective surface of the hot plate into a plurality of zones, it is possible to divide the effective surface more finely in the longitudinal direction of the sheathed heater than with conventional hot plates. Therefore, by independently controlling the temperature of each divided zone,
It becomes possible to control the temperature distribution state of the hot plate with more precision, and even when heating the hot plate to a uniform temperature, it is possible to make the temperature more uniform than with conventional methods. It is.

In addition, in this way, the hot plate can be divided into a plurality of zones whose temperature can be controlled independently of each other in the longitudinal direction of the sheathed heater, and the temperature of the hot plate can also be divided and controlled in the longitudinal direction of the sheathed heater. Since it has become like that, like a conventional hot plate,
It is no longer necessary to adjust the heater capacity of the heater element in advance according to the target heating temperature, and therefore it is no longer necessary to replace the sheathed heater every time the target heating temperature changes. . In addition, for the same reason, it has become possible to accurately control the temperature distribution state of the hot plate when controlling the temperature increase of the hot plate. This was advantageous when it was necessary to adjust the situation.

Moreover, according to the hot plate according to the present invention, by simply arranging one sheathed heater in one heater insertion hole, the hot plate can be divided into a plurality of zones in the longitudinal direction of the sheathed heater. Another advantage is that the lead wires for energizing each heater element in the heater can be drawn out from the same direction of the hot plate. If the lead wires for energizing each heater element of the sheathed heater are pulled out from the same direction of the hot plate, it becomes easier to attach the sheathed heater to the hot plate, and the routing and wiring work of the lead wires becomes easier. It will become. In addition, in the case of hot press equipment,
By loading the workpiece and unloading the molded product from the side opposite to the direction in which the lead wires are pulled out, the loading and unloading operations become easier, and safety is also improved. .

Incidentally, in the conventional heat plate in which the heat plate is divided into two zones in the longitudinal direction of the sheathed heater, two sheathed heaters are arranged in series in the heater insertion hole as described above. As the area was becoming more and more zoned,
It was not possible to pull out the lead wires for energizing each heater element from the same direction of the hot plate, which made it troublesome to attach the sheathed heater to the hot plate, route the lead wires, and perform wiring operations. It had become so.

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

First, FIG. 1 shows an example of a hot press apparatus equipped with a hot plate according to the present invention, in which reference numeral 10 denotes a fixed plate, and the four corners of the plate are provided with stays erected on a base 12. It is fixed and supported at the upper end of 14. Further, reference numeral 16 denotes a movable platen, which is fixed to a ram 20 of a cylinder 18 provided on the lower side of the base 12.
It is designed so that it can be raised and lowered according to the expansion and contraction of. As is well known, a plurality of hot plates 22 are arranged in multiple stages between the fixed platen 10 and the movable platen 16, and a workpiece such as a laminate is inserted between the hot plates 22. 24 is heated by the hot plates 22 and pressurized based on the pressing action between the fixed platen 10 and the movable platen 16.

By the way, each hot plate 22 has a rectangular planar shape, as shown in FIG. Six heater insertion holes 25 are formed at approximately equal intervals. A sheathed heater 26 as a multi-circuit sheathed heater is inserted into each of these heater insertion holes 25 from the same direction.

As shown in FIG. 3, these sheathed heaters 26 have heater elements 30 (30
A, 30B, 30C) are arranged in series, and three lead wires 32 (32A, 30C) are individually connected to one end of each heater element 30.
2B, 32C) and a lead wire 34 commonly connected to the other end of the heater element 30 extend from the opening of the sheath 28. By applying a voltage between the common lead wire 34,
These heater elements 30 can be selectively energized and heated. In this embodiment, as described above, these sheathed heaters 26 are inserted and arranged in each heater insertion hole 25 of the hot plate 22 from the same direction, and each of the sheathed heaters 26 is placed in each of the hot plates in which the sheathed heaters 26 are placed. 22 are arranged so as to face the same direction with respect to the hot press device, and the lead wires 32 and 34 drawn out from each sheathed heater 26 are respectively oriented in the direction in which the workpiece 24 is carried in (the direction in which the molded product is carried out). is routed and wired on the opposite side of the device.

Note that the heater element 30 of the sheathed heater 26 is usually wound around a predetermined ceramic core and fixed to the outer surface of the ceramic core with a heat-resistant insulating material filled between the inner surface of the sheath 28 and the inner surface of the sheath 28. It will be installed according to the requirements. Further, each of the lead wires 32 and 34 is disposed so as to penetrate through the ceramic core, and to be integrally embedded within the ceramic core while being insulated from each other at an appropriate interval. .

Further, in this embodiment, in such a hot press apparatus, the heater element 30 of the sheathed heater 26 disposed on each hot plate 22 is controlled to be energized by a control circuit as shown in FIG. As shown in Figure 2,
The effective surface (here, the entire surface) of the hot plate 22 is arranged in a grid pattern 9
Heating is controlled independently for each of the divided zones.

That is, in FIG. 4, 36 indicates the hot plate 22.
Established corresponding to each divided zone of
A temperature controller with PID control function,
The corresponding semiconductor non-contact relays (hereinafter referred to as
It is connected to 33 (abbreviated as SS relay),
Thermocouples 40 (second
Based on the temperature signal from the corresponding
The SS relay 38 is controlled to turn on and off according to a preset program. As a result, the power supplied from the power source (not shown) to each corresponding heater element 30 (here, two heater elements 30, 30) is adjusted, and each corresponding zone is heated at a preset temperature increase rate. After the temperature of each corresponding zone increases to the target heating temperature, the temperature of each corresponding zone is maintained at the target heating temperature.

Each temperature controller 36 also includes a common program setting device 41 and a common temperature setting device 4.
2 are connected, and the program setting device 41 can selectively set the program for each temperature controller 36, and the temperature setting device 42 can switch and set the target heating temperature. As a result, programs set corresponding to the target heating temperature are simultaneously selected in each temperature controller 36.

In addition. A relay circuit (not shown) connects each SS relay 38 and the power supply with a plurality of relays (here, two) selectively selected depending on the temperature of the corresponding zone.
variable resistors 42 (42A, 42B) are disposed, and when the temperature of the corresponding zone reaches a predetermined temperature lower than the target heating temperature during temperature increase control of the hot plate 22, a variable resistor 42 (42A, 42B) is installed. The resistor 42 can be switched from one with a smaller resistance value (42A) to one with a larger resistance value (42B). As a result, the rate of temperature increase in each zone during temperature increase control of the hot plate 22 is gradually slowed down, and the temperature of each divided zone, and eventually the entire temperature of the hot plate 22, reaches the target temperature. The temperature is raised as quickly as possible and stabilized with good accuracy.

According to such a hot press device, as described above, each hot plate 22 is divided into three sections in the arrangement direction of the sheathed heaters 26 and in the longitudinal direction thereof, and is divided into nine zones in a grid pattern. Since the temperature in each zone is independently controlled and raised to the same target heating temperature, there may be differences in the heat radiation state or heat transfer state in each part of the heat plate 22, or differences between the sheathed heater 26 and the heat plate 22. It is possible to reduce variations in the temperature of the hot plate 22 due to non-uniformity in the state of close contact with the hot plate, and to make the temperature of the whole hot plate 22 as uniform as possible. Variations in temperature between the two can be made as uniform as possible. In this embodiment, as described above, each hot plate 22 is divided into three parts not only in the arrangement direction of the sheathed heaters 26 but also in the longitudinal direction thereof. Compared to conventional heat plates that are divided, the temperature of the hot plate 22 can be heated more uniformly to the target heating temperature, and therefore molded products (laminate molded products) of higher quality than before can be manufactured. It is possible.

In addition, in this way, the hot plate 22 is connected to the sheathed heater 2
6 is also divided into three zones in the longitudinal direction of the sheathed heater 26, and the temperature of the hot plate 22 can be made more uniform in the longitudinal direction of the sheathed heater 26 than in the past. It is no longer particularly necessary to adjust the heater capacity of each heater element 30 of the sheathed heater 26 in advance according to the target heating temperature, and therefore it is necessary to replace the sheathed heater 26 every time the target heating temperature changes. It was gone. Furthermore, for the same reason, it has become possible to accurately control the temperature distribution state of the hot plate 22 when controlling the temperature increase of the hot plate 22. Therefore, when controlling the temperature increase of the hot plate 22, It has also become possible to make the temperature of the hot plate 22 as uniform as possible, thereby improving product quality.

Furthermore, as described above, since the lead wires 30 and 32 for energizing the heater element 30 of each sheathed heater 26 are drawn out to the same side of the hot press device, This has the advantage that the mounting operation is simple, and the wiring and routing of the lead wires 32 and 34 is also simple. In addition, since the lead wires 32 and 34 are drawn out and wired in the opposite direction to the direction in which the workpiece 24 is carried in, the workpiece 24 is easily carried (charged) between the hot plates 22.
Another advantage is that operations and product transport operations can be performed easily and safely.

Although one embodiment of the present invention has been described above, this is a literal illustration, and it goes without saying that the present invention should not be interpreted as being limited to this specific example.

For example, in the embodiment, each sheathed heater 26
Three heater elements 30 are arranged in each of the sheathed heaters 26, and the hot plate 22 is divided into three in the longitudinal direction of the sheathed heater 26. The number of divisions of the hot plate 22 in the longitudinal direction is not necessarily limited to this, but as shown in FIG. The hot plate 22 may be divided into two in the longitudinal direction of the heater 26, or four or more may be provided and the heat plate 22 may be divided according to the number of the heaters. Note that the larger the number of heater elements 30 disposed in the sheathed heater 26, the more precisely the temperature distribution state of each hot plate 22 can be controlled, and the more uniform the temperature of the hot plates 22 can be. However, the number of lead wires that can be drawn out from each sheathed heater 26 is limited by the dimensions of the sheathed heater, the voltage applied between each lead wire, the usage conditions (environmental conditions) of the hot plate 22, etc. teeth,
The number of heater elements 30 to be provided will be selected according to these conditions.

Further, in the embodiment, each heater element 30A, 30B,
One end of the lead wire 30C is connected to the common lead wire 34, and the other ends thereof are connected to separate lead wires 32A, 32B, and 32C, respectively.
4 and each corresponding lead wire 32, these heater elements 30 were independently energized and controlled, as shown in FIGS. 6 to 8. Depending on the situation, the other ends of any two heater elements 30 may be connected to a common lead wire 32D to control the energization of any two heater elements 30 at the same time. It is possible, and furthermore, as shown in FIG. 9, it is also possible to simultaneously control the energization of three heater elements 30 (30A, 30B, 30C) through common lead wires 34 and 32E. It is. In such a case, the other ends of any two or three heater elements 30 may be connected inside the sheathed heater 26 or outside the sheathed heater 26. However, in order to reduce the number of lead wires drawn out from the sheathed heater 26, it is desirable to connect them inside the sheathed heater 26, and from the standpoint of design freedom, it is preferable to connect them externally. This is desirable. Moreover, the manner of connection of each heater element 30 increases as the number of heater elements 30 disposed within the sheathed heater 26 increases.

Further, in the above embodiment, each end of each heater element 30 disposed in the sheathed heater 26 was connected to the common lead wire 34, but the present invention is not limited to this, and each heater element 30 is connected to the common lead wire 34. It is also possible to draw out the lead wires for energizing the element 30 separately. However, in this case, the number of lead wires per number of arranged heater elements 30 increases, so the number of heater elements 30 that can be arranged in the sheathed heater 26 increases compared to the case of the above embodiment. will be limited accordingly. In the hot press device, the workpiece 24 is sometimes processed with the entire hot press device housed in a vacuum box, so it is desirable to arrange the lead wires at a distance that does not cause vacuum discharge. Therefore, in such a case, as the number of lead wires arranged per heater element 30 increases, it is inevitable that the number of heater elements 30 that can be arranged in the sheathed heater 26 decreases. It is.

Further, in the above embodiment, a thermocouple 40 and a temperature controller 36 were provided for each divided zone of the hot plate 22, but as shown in FIG. It is also possible to provide the thermocouple 40 and the temperature controller 36 in common to the heater elements 30 of a plurality of zones.

Furthermore, as shown in FIG. 11, the temperature controller 36 can be provided commonly to the heater elements 30 of each divided zone. That is, in FIG. 11, the temperature controller 36 is connected to the thermocouple 40 disposed in each divided zone via the input selection circuit 46.
Temperature signals from each thermocouple 40 are sequentially taken in at a predetermined period. And those thermocouples 4
A control signal (analog signal) for each corresponding zone is output in synchronization with the switching cycle of 0, and is supplied to the converter 48. Also,
In the converter 48, the control signal is ON.
The signal is converted into an OFF signal and supplied to each corresponding SS relay 38 through the output selection circuit 50. Then, as in the previous example, this
The heater elements 30 disposed in each corresponding zone are energized by the SS relay 38, and the temperature of each zone is controlled. Note that a program setting device 41 is connected to the temperature controller 36 in the same manner as in the previous embodiment, and the heating program corresponding to each zone can be individually set by this program setting device 41. A temperature setting device 42 similar to that of the above embodiment is connected, and the target heating temperature is switched and set by this temperature setting device 42, so that the temperature controller 36 adjusts the temperature of each zone set according to the target heating temperature. The heating program is now selected. In addition, when the target heating temperature is maintained, the signal supplied from the output selection circuit 50 to each SS relay 38 is controlled ON/OFF at the scanning cycle of the thermocouple 40 according to the comparison result between the set temperature and the measured temperature. It will be done. Furthermore, here, as shown in the figure, three variable resistors 44 (44A, 44B, 44C) are connected in parallel to each SS relay 38, and these variable resistors 44 are selected. By making a uniform selection, the temperature increase rate of each zone can be reduced in three stages.

In addition, in the above embodiment, an example was described in which the present invention was applied to a hot plate of a hot press machine, but the present invention is not limited to this, and can also be applied to an injection molding machine, etc. is possible.

In addition, although not listed one by one, various modifications,
Things that can be implemented with modifications, improvements, etc. are:
It goes without saying.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of a hot press device equipped with a hot plate according to the present invention, and FIG.
FIG. 3 is a plan view schematically showing the hot plate shown in the figure, and FIG. 3 is a schematic cross-sectional view for explaining a sheathed heater used in the hot plate shown in FIG. 2. FIG. 4 is a circuit diagram showing an example of a heating control circuit for the hot plate shown in FIG. 2. FIG. 5 is a diagram corresponding to FIG. 3 showing a sheathed heater in another embodiment of the present invention. Figures 6, 7, 8 and 9 are 3
FIG. 4 is a circuit diagram showing a different wiring configuration from that shown in FIG. 3 of a sheathed heater in which two heater elements are arranged. Figures 10 and 11 are the second
FIG. 4 is a circuit diagram showing an example of a heating control circuit different from that shown in FIG. 4 for the hot plate shown in the figure. 10: Fixed plate, 16: Movable plate, 22: Hot plate, 2
5: Heater insertion hole, 26: Sheathed heater (multi-circuit sheathed heater), 30 (30A, 30B, 30
C): Heater element, 32 (32A, 32B,
32C, 32D, 32E), 34: Lead wire, 3
6: Temperature controller, 38: Semiconductor non-contact relay, 40: Thermocouple, 41: Program setting device, 4
2: Temperature setting device.

Claims (1)

[Claims] 1. A multi-circuit sheathed heater in which a plurality of heater elements are arranged in a longitudinal direction of the sheath independently and in series within a longitudinally tubular sheath. 1. A hot plate characterized in that the hot plate portions are arranged in respective heater insertion holes so that each of the hot plate portions can be heated by each heater element of the multi-circuit sheathed heater. 2. The plurality of heater elements are energized and controlled by at least two independent circuits, so that the heating of the heater element disposed portion of the hot plate can be independently controlled.
The heating plate described in section.