JPH1158508A - Heat-control of sheet-form material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly heat a sheet-form material and increase the productivity, and at the same time, properly perform the heating control by a method wherein at a pre-heating location, the surface temperature is quickly heated to a target temperature, and in a main heating, the sheet-form material is heated to the core by keeping a temperature at which the surface does not melt, and the sheet-form material is transferred to a forming process. SOLUTION: A heating system is constituted of a pre-heating device 3 to heat a sheet-form material 1 which is fed from a base material setting location 2, a main device 4 following the pre-heating device 3, a forming press location 5 and a material, carrying device, and at the locations of the heating devices 3, 4, heater retreat locations 6, 7 for respective heatings are provided. In this case, the material 1 is set on a gripping device at the setting location 2, and then, the material 1 is moved to the location of the heating device 3, and is heated for a specified period of time by the maximum heating output by using a pre-heating means which can retreat. At this location of the device 3, the material 1 is heated to a temperature at which the surface of the material 1 does not melt, and the material 1 is moved to the location of the device 4, and a heating is started by a heating means, and after keeping it in the allowable range of a target temperature for a fixed period of time, the material 1 is moved to the location 5 and is carried out after being formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating a sheet-like material such as a thermoplastic resin to a suitable temperature and then forming the sheet-like material by vacuum forming, press forming, pressure forming, and the like. The present invention relates to a heating control method for a material in a shape.

[0002]

2. Description of the Related Art Conventionally, sheet materials have been heated by radiant heat using a far-infrared heater or the like or heated in a constant temperature furnace. For example, a method of heating a resin sheet using a heater and a radiation thermometer having high responsiveness of heat generation control is known (JP-A-63-130332). In this heating method, while the radiation thermometer generates the target temperature signal and simultaneously supplies the next resin sheet to the heater, when the supply of the resin sheet is delayed, the heating value of the heater is generated. In this method, the residual heat-completed resin sheet is kept at a temperature near the target by controlling the temperature of the resin sheet. However, in this method, since the resin sheet is heated from a cold temperature, there is a problem that the heating time is long and the productivity is not so high. This problem is particularly caused when the molding material is resin-sealed.
If the sheet material is not a sheet but a thick sheet material containing heat-insulating air, even if the surface temperature of the sheet material is high, the core of the sheet material is not sufficiently heated and is not sufficiently heated. -The entire material is not heated uniformly. On the other hand, if the core is heated for a long time to sufficiently heat it, the surface of the sheet-like material is melted by overheating, and cannot be used as a product. For this reason, in order to heat the core of the sheet-like material and prevent the surface from being melted, the material is heated for a long time at such a low temperature that the surface is not melted. . SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is suitable for a sheet-like material in which the sheet-like material is rapidly heated to increase productivity and uniform heating is difficult. It is an object of the present invention to provide a heating control method for a shape material.

[0003]

In order to achieve the above object, a method for controlling the heating of a sheet-like material according to the present invention is a means for rapidly heating a material to a core portion, wherein a surface temperature is quickly set at a preheating position. Heat to the temperature, maintain the temperature at which the surface does not melt in the main heating, and heat to the core.

According to the present invention, after heating the sheet-like material at the pre-heating position, the sheet is further heated at the main heating position, so that the heating time may be short, and furthermore, the allowable range of the target temperature at the main heating position. When the sheet-like material is held inside, the heating of the sheet-like material is completed and the process proceeds to the molding step, so that the sheet-like material is quickly heated to increase the productivity and to make uniform heating difficult. Heat control can be performed accurately even with a material in the form of a plate.

In the present invention, the sheet-like material refers to a composite material such as a resin sheet such as polyurethane or polyvinyl chloride, a synthetic resin-impregnated foam sheet, a sheet molding, and the like. Ceiling materials and automotive interior materials. In the present invention, the preheating position is a position where the sheet material is heated from room temperature for a predetermined time, and the sheet material is not softened only by being heated here. It is not possible to proceed to the molding step as it is.
The retractable preheating means is, for example, a block heater arranged on a movable gripping device. In the present invention, the main heating position is a heating position moved from the preliminary heating position toward the forming position. The non-retractable main heating means is such that a block-shaped heater or the like is provided above the sheet moving position of the main heating position. The target temperature refers to the temperature of the sheet material suitable for molding, and the temperature varies depending on the material, thickness, room temperature, and the like of the sheet. Also, the allowable temperature range varies depending on the material of the sheet and the like. Fuzzy control is control which is also called fuzzy logic control.
This is a control method used in the control field.

[0006]

Embodiment 1 Hereinafter, a detailed description will be given based on FIG. 1 which is a schematic view showing a molding line of the present invention. In FIG.
A preheating position 3 for heating the sheet material 1 sent from the base material setting position 2 of the sheet material 1, a subsequent main heating position 4, a forming press position 5 for the sheet material 1, and A material transport device (not shown) is provided. A preheating heater retracting position 6 is provided at the preheating position 3. The main heating position 4 is also located at the main heating position.
A retreat position 7 is provided.

FIG. 2 is a schematic front view showing details of the preheating heater retreat position 6. In FIG. 2, both ends of the sheet material 1 are gripped by a gripping device 8. Heaters 9 and 9 are provided above and below the sheet-like material 1, respectively.
It is fixed to. The bogie 10 is configured to be able to move vertically between wheels 11 and rails 12 between a sheet-like material gripping device 8 and a heater retreat position.

FIG. 3 is a diagram schematically showing a heating control device at a preheating position. The heater 9 has a built-in thermocouple (not shown), sends a thermocouple signal with a built-in heater 9 to a controller, and controls the heating of the heater 9 based on the signal.

FIG. 4 is a diagram showing a heating control device at the main heating position. The heater 9 is provided with a radiation thermometer, and sends a signal of the radiation thermometer to the controller to control the heating of the heater 9 based on the signal.

The heating and forming of the sheet-like material 1 in the sheet-like material forming line configured as described above will be described below. FIG. 5 is a schematic diagram showing a heating control procedure of the sheet-like material 1 including the preheating position and the main heating position. 1 and 5, the sheet-like material 1 is set on a holding device 8 at a substrate setting position 2 at room temperature. Next, when the sheet-like material 1 moves to the preheating position 3, the preheating position 3 heats the sheet-like material 1 for a predetermined time with the maximum heating output by using a retractable preheating means composed of a block type heater. The sheet-like material 1 preheated according to the condition of the base material setting position 2 or the main heating position 4
Cannot be moved, the heaters 9, 9 are moved to the shelter. Then, at the preheating position 3, the sheet material 1 is heated to a temperature at which the surface of the sheet material 1 does not melt. Next, the sheet-like material 1 is moved to the main heating position 4, and heating is started at the main heating position 4 using the retractable main heating means. In addition,
The evacuation is not always essential at the main heating position, and evacuation may be possible depending on the material. Here, as shown in FIG. 5, while controlling the surface temperature of the material periodically, the temperature is controlled to be an appropriate temperature when the surface temperature is kept within an allowable range of the target temperature for a certain time. The holding time varies depending on the material, but is preferably 3 to 5 seconds. If the length is longer than this, the significance of performing the preheating is lost. Also, if the length is shorter than this, the center of the material is often not heated. Thereafter, the sheet-like material 1 is moved to the molding position 3 and molded. Further, after the molding, it is carried out by a carrying device (not shown).

Here, the fuzzy control used at the main heating position will be described. In the heating control according to the present embodiment, two-stage fuzzy control is used in the main heating control. The main heating step includes a step of heating with a high-gain first-stage fuzzy control for suppressing the overshoot from the overshoot suppression start temperature and a first step from the stable control start temperature. The heating is performed by the second-stage fuzzy control having a lower gain than that of the second-stage fuzzy control.

The fuzzy control in the first stage and the fuzzy control in the second stage are independent but the same fuzzy control. More specifically, as shown in FIG. 6, a temperature deviation membership function and a temperature rise rate membership function are provided in the antecedent part. The consequent part usually uses a membership function, but uses a constant for simplicity. Further, it has the control rules shown in Table 1.

[0013]

[Table 1]

Here, the first stage fuzzy control and the second stage fuzzy control have different conditions in the antecedent part. Specifically, the fuzzy control of the first stage has a wider range of temperature deviation and temperature rise rate, and the fuzzy control of the second stage aims at stabilizing the temperature. Temperature deviation and heating rate.

The first-stage fuzzy control and the second-stage fuzzy control have different conditions in the consequent part. Specifically, in the first stage fuzzy control,
In order to suppress the burst, the gain has a higher value, and the second stage fuzzy control has a lower value so as not to hunt.

If there is a temperature deviation and a temperature rise rate as shown in FIG. 7, the related control rule is as shown in Expression 1.

[0017]

(Equation 1)

The output addition is calculated as in the following equation (2). Specifically, the smaller of the degree of conformity of the temperature deviation and the rate of temperature rise of the antecedent part is adopted, the product of the value and the antecedent part constant is obtained, the weighted average of the related rules is obtained, and the output addition amount I do.

[0019]

(Equation 2)

Here, the output addition is added to the previous output. This is an additional addition, and the output this time is calculated as in Expression 3.

[0021]

(Equation 3)

As described above, the two types of fuzzy control having the conditions of the temperature deviation and the temperature increase rate enable the overheat to be reduced and the temperature to be stably controlled.

As is apparent from the above description, the present invention can be applied to a sheet-like material in which the sheet-like material is rapidly heated to increase productivity and uniform heating is difficult. A suitable method of controlling the heating of the sheet-like material can be provided, and the effect on the industry is remarkable.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a molding line according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing details of a heater retracting position according to the present invention.

FIG. 3 is a schematic diagram showing a heating control device at a preheating position according to the present invention.

FIG. 4 is a schematic diagram showing a heating control device at a main heating position according to the present invention.

FIG. 5 is a schematic view showing heating control of the sheet-like material of the present invention.

FIG. 6 is a diagram showing fuzzy control conditions of the present invention.

FIG. 7 is a fuzzy graph relating to temperature deviation and temperature rise rate according to the present invention.
It is a figure showing a control condition.

[Explanation of symbols]

 1 sheet-like material 2 base material setting position 3 preheating position 4 heating position

Claims (6)

[Claims] 1. A heating control method for a sheet-like material, comprising: a step of heating the sheet-like material at a preheating position; and a step of further heating the sheet-like material at a subsequent main heating position. A heating step using preheating means capable of being retracted from the heating position at the preheating position, and a heating step further using main heating means at the main heating position, wherein the main heating step is performed at a target temperature. Wherein the heating of the sheet-like material is completed when the temperature is maintained within the allowable range for a predetermined time, and the process proceeds to a molding step. 2. The sheet-like material according to claim 1, wherein said preheating means is retracted from a heating position when a target heating time for preheating the sheet material is exceeded. Heating control method. 3. The method according to claim 1, wherein the main heating step is performed in two stages.
Control from the overshoot suppression start temperature
High-gain first-stage fuzz to reduce bursting
3. The sheet-like material according to claim 1, wherein the heating is performed by fuzzy control having a lower gain than the fuzzy control of the first stage from the stable control start temperature. Heating control method. 4. The heating method according to claim 1, wherein the main heating step is controlled by a signal output from a radiation thermometer for measuring the temperature of the sheet-like material. The heating control method for a sheet-like material according to the above item. 5. The sheet-like material according to claim 1, wherein the sheet-like material is a material containing air between skins. Material heating control method. 6. A heating control for a sheet-like material comprising a pre-heating step of heating the sheet-like material at a pre-heating position and a main heating step of further heating the sheet-like material at a subsequent main heating position. A method wherein the target heating time of the sheet material is exceeded at the preheating position,
Heating is performed by using preheating means retreating from the preheating position, and heating is performed using main heating means capable of retreating even at the main heating position, and the main heating step further starts the overshoot suppression. A step of heating with a high-gain first-stage fuzzy control that suppresses overshoot from a temperature, and a step of heating from a stable control start temperature by a fuzzy control with a lower gain than the first-stage fuzzy control. Wherein the main heating step is controlled by a signal output from a radiation thermometer for measuring the temperature of the sheet-like material.