JPS62126581A - Atmospheric temperature correction of induction heating temperature - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention uses high-frequency induction heating means to heat a member to
Relating to an outside temperature correction method for induction heating temperature suitable for baking paint or solidifying binder by raising the temperature to a low temperature of about 50°C, at least 300°C or lower, or raising the temperature and keeping the temperature for a predetermined period of time. .

(Prior technology) High-frequency induction heating means is used to heat up the component itself for baking paint and solidifying binder, and by utilizing that temperature, processing can be completed in a short time and requires less space, making it possible to use it on a production line. The use of this method tends to become widespread because it is easy to incorporate.

Conventionally, the optimal heating temperature for the component for baking the paint used, solidifying the binder, etc. was found through experiment or experience, and the mass and coil shape of the component were determined in order to raise the temperature of the component to that temperature within a predetermined time. In relation to the heating time, etc., the power output by the high frequency power source is set to a predetermined value for heating, and the initial power setting was not changed unless there was a change in the quality of the paint, binder, etc. used.

(Problems with the prior art) However, while paints, binders, etc. have the property of being relatively sensitive to temperature, on the other hand, the outside temperature changes daily and depending on the season by 30 to 40 degrees Celsius. Therefore, in low temperature region heating, the temperature difference is as much as 10 to 20%. Therefore, as shown in Figure 2, when setting the power of the high-frequency power supply in experiments, it is necessary to set the power that can raise the temperature to Cn within the heating time period tO to t2J without taking the outside temperature conditions into account. For example, use transmitted from a member whose temperature has increased due to the input energy of the input power.

If the thermal energy applied to the paint, etc. corresponds to the area indicated by the crossed diagonal lines between rtl and t3J during which the temperature is maintained at a temperature Co or higher and Cn or lower, then the optimum baking is set as a finish. When heating is performed at an outside temperature higher than the outside temperature during the experiment, the input energy is constant, so rtl-α ~ t3 + β over the elapsed time
'' maintains a temperature Co or higher, and the temperature higher than the temperature Cn based on the heating temperature is also Cn', so the thermal energy transferred from the member to the paint etc. is
This corresponds to the sum of the area indicated by crossed diagonal lines and the area indicated by diagonal lines, resulting in excessive thermal energy being applied. Conversely, if the outside temperature at the time of heating is lower than that at the time of the experiment, the provision of thermal energy will be insufficient.

In addition, when heating is performed in two stages: temperature raising heating and subsequent warming heating with reduced power, the heating time will be longer than in the above example, so under the condition that the energy input to the component is constant, The temperature difference will further accumulate,
The excess or deficiency of thermal energy applied to paints, etc. used increases.

Furthermore, when induction heating is performed on components on a continuous production line, and the temperature of the component increases in the previous process, and there is a lot of residual heat during the induction heating, even if the residual heat is Even if you determine the thermal energy to be applied to the paint etc. to be used, and then set the electric power by calculating the energy input to the parts,
The residual heat depends on the outside temperature, and it is not always guaranteed that the running speed of the line remains constant, resulting in an excess or deficiency of heat energy being applied to the paint etc. used.

Too much or too little of the thermal energy applied has a large effect on the peeling factors of paints, binders, etc. and on the bonding strength, leading to variations in finished quality, so countermeasures have been desired.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems that exist when induction heating a member to a low temperature that is affected by changes in outside temperature. A method for correcting the outside temperature of the induction heating temperature, which eliminates excess or deficiency of thermal energy applied to the paint, etc., and achieves high quality and leveled finish by correcting the heating temperature of the component to always be constant. The purpose is to provide

(Structure of the Invention) The structure of the present invention is as follows: (2) When a member is heated to a low temperature of 300°C or less by Ll high-frequency induction heating means, or is heated and kept warm for a predetermined period of time, (3)
Input energy (Kw) determined in relation to multiple stages of outside air temperature and the mass of the member required to raise the temperature of the member to a predetermined temperature or to keep it warm for a predetermined time after raising the temperature according to each stage.
(4) Corresponds to the adjustment value of the power setting device of the high-frequency power supply, which is determined according to the input energy (Kw) of multiple stages and each input energy (Kw) within the specified energization time. (5) the controller is configured to output a current signal according to the adjustment value to the power setting device; (6) the controller is configured to output a current signal corresponding to the adjustment value to the power setting device; The outside air temperature or the surface temperature of the component immediately before the component is heated is set to be measured and input to the controller, and (7) the controller controls the set power of the high-frequency power source based on the input measurement value. A method for correcting induction heating temperature for outside air temperature is provided.

(Function of the Invention) The present invention performs heating with variable input energy that is automatically corrected according to the outside temperature or residual heat in low-temperature heating of a member by high-frequency induction heating means, so that the heating temperature of the member is constantly maintained. It has the effect of keeping it constant.

(Example) The present invention will be described in detail below according to the block diagram shown in FIG.

In the figure, 1 is a heating station, 2 is a high frequency power source for heating, 3 is a controller, and 4 is a temperature measurement probe. The heating station 1 includes an induction heating coil connected to the high-frequency power source 2 and a member that is arranged opposite to the induction heating coil with a predetermined gap therebetween or that moves while facing the induction heating coil. The high frequency power source 2 is a known power source, and is equipped with a power setting device that can change the voltage input to the negative side. The controller 3 is a device that executes the method of the present invention, and has storage and calculation functions, a built-in temperature measuring device that receives temperature information measured by the probe 4, and a power setting device for the high frequency power source 2. The current signal is configured to be able to output a current signal that causes a predetermined adjustment value to be obtained. The temperature measuring probe 4 is made of, for example, a PT resistance thermometer, and is arranged close to the member arrangement position of the heating station 1, and can measure the temperature inside the heating station 1, or can the member be moved through an advance/retreat mechanism. The sensor is configured to be in contact with the surface for, for example, 2 to 3 seconds to be able to measure the surface temperature.

Therefore, from pre-calculation or experiment, for example, θ℃, 5℃
Since the input energy (Kw) required to raise the temperature of each member to a predetermined temperature within a predetermined energization time can be determined for each multiple temperature stage such as , 10℃, ...-40℃, the temperature and Input energy (K) according to each temperature
w) The outside temperature corrected power chart shown in Table 1 is stored in the controller 3. In this case, it goes without saying that the input energy (Kw) is determined depending on the mass of the member to be heated.

Further, the power setter has a current signal normally selected in the range of 4 to 20 mA, and adjusts the set power within the output range of 0 to 100%. Therefore, in order to adjust the power setter in accordance with each input energy (Kw) in the above outside temperature corrected power chart, the setting power adjustment for each input energy (Kw) and the power setter as shown in Table 2. Current signal (m
A) A high frequency power source power adjustment chart is created and the high frequency power source power adjustment chart is stored in the controller 3.

However, in practice, the output % should be within a certain range (for example, 70~
100%), and the current signal is allocated within that range; however, to simplify the explanation, the high frequency power supply power adjustment chart in Table 2 for the example is set to the 100% range.

Furthermore, in this embodiment, the output percentage has a reciprocal relationship with the magnitude of the current signal (mA).

Furthermore, the controller 3 has a program that allows interpolation from upper and lower input energy (Kw) set values that sandwich the input measured value when the measured value input from the temperature measurement probe 4 indicates an intermediate value of the set temperature stage. will be incorporated.

The case of induction heating a member using the embodiment apparatus configured and set as described above will be described below with reference to Tables 1 and 2.

Immediately after a member coated with paint or the like is carried into the heating station 1, outside temperature information is input from the temperature measurement probe 4 to the controller 3.

For example, if the input measurement value is 25°C, the controller 3 selects input energy P25 (Kw) corresponding to the temperature based on the stored outside temperature correction power chart, and then adjusts the stored high-frequency power supply power. Select the current signal 14 (mA) corresponding to the input energy P25 (Kw) according to the chart, and
) is output to the power setting device. As mentioned above, the power setting device is configured to adjust to a predetermined power according to the input current signal, so the high frequency power source 2 supplies the high frequency current according to the power setting of the power setting device to the heating coil in the heating station 1. energized for a predetermined period of time.

By applying the current, the temperature of the component rises to a predetermined temperature within a predetermined time, and a predetermined amount of thermal energy is applied from the heated component to the paint, etc., and the paint, etc. is heated under ideal conditions with appropriate applied thermal energy. Baked or solidified.

(Other Examples) In the above explanation, an example was given in which the outside temperature was 25°C. For example, when the outside temperature is 23°C, an interpolation operation is performed by calculation, and the current signal 13 is sent to the power setting device. will be output.

In addition, when the temperature measurement probe 4 is set to contact the surface of the component, the surface temperature of the component at the start of heating and the surface temperature of the component that has risen by a predetermined time sufficiently shorter than the energization time are measured. The temperature difference may be calculated, and if the temperature difference is within a predetermined tolerance range, the energization is continued, and if the temperature difference exceeds the predetermined tolerance range, the energization is stopped. With this configuration, since the power-time product is calculated, it is possible to monitor whether the high-frequency power source is normally operating at the set power.

In addition, when performing two-stage heating, different input energy determined by calculation is selected for heating at high temperature and heating at constant temperature, and a predetermined current signal is output from controller 3 to the power setting device with a time difference. A sequence will be created so that

(Effects of the Invention) By carrying out the present invention, low-temperature one-degree heating of members using induction heating means is not affected by changes in outside temperature or residual heat, and the heating temperature is always constant. Therefore,
There is no excess or deficiency in the thermal energy applied to the paint, binder, etc. used, and the baked or solidified finish maintains high quality and is leveled out, and is prized for its remarkable effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating the method of the present invention, and FIG. 2 is a diagram showing the relationship between elapsed time and heating temperature, illustrating the problems of the conventional method.

Claims (1)

[Claims] 1) When heating a member to a low temperature of 300°C or less using high-frequency induction heating means, or after raising the temperature and keeping it warm for a predetermined period of time, a controller equipped with a memory and calculation function is configured to perform multiple stages of external heating. An outside temperature correction chart that compares the air temperature with the input energy (Kw) determined in relation to the mass of the member required to raise the temperature of the member to a predetermined temperature or to heat the member and keep it warm for a predetermined period of time according to each stage; A high-frequency power supply power adjustment chart that compares the input energy (Kw) of multiple stages and the current signal corresponding to the adjustment value of the power setting device of the high-frequency power supply determined according to each input energy (Kw) within a predetermined energization time. In addition to being stored in advance, the controller is configured to output a current signal according to the adjustment value to the power setting device, and measures the outside temperature or the surface temperature of the member immediately before heating the member and inputs it to the controller. A method for correcting an outside temperature of an induction heating temperature, characterized in that the controller controls the set power of a high frequency power source based on an input measured value. 2) When the measured value input to the controller indicates an intermediate value of each stage of outside temperature, interpolation is performed using the input energy (Kw) corresponding to the upper and lower stages sandwiching the intermediate value. How to correct induction heating temperature for outside temperature. 3) The outside temperature correction method for induction heating temperature according to claim 1, wherein the measurement of the surface temperature of a member includes a case where the member has residual heat from a previous process.