JP2589754B2 - Control method of heater for vapor phase soldering - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of controlling a vapor phase soldering heater for heating an inert liquid used in a vapor phase soldering apparatus.

(Prior Art) In a vapor phase soldering apparatus, as shown in FIG. 3, an inert liquid 12 is stored at the bottom of a steam tank 11, and the inert liquid
Is heated by the heater 13 to evaporate to form an inert saturated vapor phase 14 inside the steam tank 11,
The work 16 carried into the saturated vapor phase 14 by the work conveyor 15 inserted inside the saturated vapor phase 14
Is reflow soldered by the latent heat of vaporization.

In a vapor phase soldering apparatus of this kind, a conventional method of controlling the vapor level of the inert vapor phase 14 is to set the thermocouple (CA, 1.6 m) to a desired vapor level as shown in FIG.
(diameter m) 17 is set, and this thermocouple 17 is connected to a temperature indicating controller (not shown), and the power supply to the heater 13 is controlled on / off by the temperature indicating controller.

That is, the temperature of the vapor phase 14 is controlled by the temperature indicating controller.
Set to 215 ° C., the temperature indicating controller performs PID operation on the deviation between the set value and the measured value obtained from the thermocouple 17, and turns on / off the heater 13 by the output of the temperature indicating adjusting type. Control. The current of 200 V AC supplied to the heater repeats energization and non-energization.

(Problems to be Solved by the Invention) In such an on / off control, the temperature of the saturated vapor phase 14 rapidly drops when the heater is turned off, and the temperature rises rapidly when the heater is turned on. Is unstable. In addition, a work (printer wiring board) 16 which becomes a disturbance to the saturated vapor phase 14 is carried in or an air flow causes the vapor phase.
Even if the temperature of 14 changes, the on / off control may not be performed if the amount of temperature change is small.

Further, in the conventional on / off control, there is a problem that the burden on the heater and the heat transfer cement used for indirect heating is large, and the life thereof is relatively short.

The present invention provides a vapor-phase type heater capable of continuously and variably controlling a heater used for vapor-phase soldering so as to control the vapor level of an inert vapor phase with high accuracy and to extend the life of the heater and the like. An object of the present invention is to provide a method for controlling a soldering heater.

(Means for Solving the Problems) According to the method for controlling a vapor-phase soldering heater according to the first aspect of the present invention, an inert liquid 12 housed in a lower part of a steam tank 11 is heated and Inert vapor phase for reflow soldering
In the heater control method for forming the heater 14, the electric power supplied to the heater 22 is controlled by the temperature indicating controller 23 to make the inert vapor phase 14.
The phase is controlled in accordance with the deviation between the measured temperature and the set temperature.

The method for controlling a vapor-phase soldering heater according to the second aspect of the present invention is a method of controlling an inert vapor phase for reflow soldering by heating an inert liquid contained in a lower portion of a vapor tank. In the method for controlling a heater forming 14, the heater includes:
A heating heater 21 for supplying a large amount of necessary heat and a control heater 22 for supplementing the heat within the control range;
The power supplied to the power supply 21 is phase-controlled by manual adjustment, and the power supplied to the control heater 22 is phase-controlled by the temperature indicating controller 23 in accordance with the deviation between the measured temperature of the inert vapor phase 14 and the set temperature. Things.

(Action) In the method for controlling a vapor-phase soldering heater according to the first aspect of the present invention, the temperature indicating controller 23 compares the measured temperature of the inert vapor phase 14 with the set temperature, and measures the inert vapor phase 14. If the temperature is lower than the set temperature, the conduction angle of the AC power supply waveform supplied to the heater 22 increases, more current is supplied to the heater 22, and the measured temperature of the inert vapor phase 14 is lower than the set temperature. If it is high, the conduction angle is reduced, and the amount of power supplied to the heater 22 is reduced. By controlling the phase of the power supplied to the heater 22, the vapor level is maintained at the best level.

In the method for controlling a vapor-phase soldering heater according to the second aspect of the present invention, the vapor level is raised to a level close to a desired level by a warming heater 21 to which electric power phase-controlled by manual adjustment is supplied, and the remaining desired level is maintained. Until the above, the vapor level is raised by the control heater 22 to which the power controlled by the temperature indicating controller 23 is supplied, and the power supplied to the control heater 22 is controlled so that the desired level is maintained at the set temperature. Controlled.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. Note that the same reference numerals are given to the same parts as those in the related art.

An insulated liquid 12 is stored at the bottom of the steam tank 11, and a heater for supplying a large amount of necessary heat to the lower side of the steam tank 11.
21 and control heaters 22 for supplementing the heat generation within the control range are provided alternately at a ratio of 1: 1 or 2: 1. The heaters 21 and 22 are provided in a heat transfer medium such as heat transfer cement, and the amount of heat generated by the heater is indirectly transmitted to the inert liquid 12 via the heat transfer medium.

Then, the inert liquid 12 is supplied to the warming heater 21 and the control heater.
Heated and evaporated by 22, an inert saturated vapor phase 14 is formed in the steam tank 11, and the work 16 carried into the saturated vapor phase 14 by the work conveyor 15 inserted in the steam tank 11. Is reflow soldered by the latent heat of vaporization of the saturated vapor phase 14.

In this type of vapor-phase soldering apparatus, a CA thermocouple 17 is set at a desired vapor level, and this thermocouple 17 is connected to a temperature indicating controller 23, and this temperature indicating controller 23 is connected to a phase controller 24. 200V via this phase controller 24
An AC power supply is connected to the control heater 22.

Also provided is a phase controller 26 which is adjusted by a manual volume 25, through which a 200 V
An AC power supply is connected to the heater 21.

As the phase controllers 24 and 26, a thyristor type AC power regulator (Vari Tap) is used, and as the temperature indicating controller 23, a PID controller is used. The PID controller generates an output signal (PID current... 4 to 20 mA) for a comparison (P) operation, an integration (I) operation, and a differentiation (D) operation. The phase of the AC power regulator is controlled.

Then, the phase of the warming heater 21 is controlled by the phase controller 26 adjusted by the manual volume 25, so that the temperature of the inert liquid 12 is heated to 200 ° C. or more, and the saturated vapor phase 14 is heated.
Desired vapor level (height with thermocouple 17)
Up to about 80%. The manual volume 25 is fixed once it has been adjusted. In addition, the control heater 22 compensates for the heat amount of the insufficient heat of the heat insulation heater 21. That is, the phase power of the AC power supplied to the control heater 22 is controlled by the phase controller 24 automatically controlled by the temperature indicating controller 23, and the inert liquid 12 is heated to about 215 ° C., and the desired height ( The vapor level is raised to the height at which the thermocouple 17 is provided). Thereafter, the phase of the control heater 22 is controlled so that the desired level is maintained at the set temperature.

More specifically, the temperature of the inert vapor phase measured by the thermocouple 17 and the temperature (215 ° C.) set by the temperature indicating controller 23 are compared by the temperature indicating controller 23. A PID current corresponding to the temperature deviation is output, and a phase controller (thyristor type) is used according to the magnitude of the PID current (4 to 20 mA) in accordance with the waveform of the AC power supply supplied to the heater shown in FIG. The phase angles α ₁ and α _{2 of} the gate pulse that triggers the thyristor of the AC power regulator 24 are controlled. In FIG. 2, the phase angle (180 ° −
α ₁ or α ₂ ) is the conduction angle β at which power is supplied to the heater.
_1, is a β _2. When the PID current is 4 mA, the conduction angles β ₁ and β ₂ are 0
When the PID current is 20 mA, the conduction angles β ₁ and β ₂ are 180 °.

For example, when the measured temperature of the inert vapor phase 14 is lower than the set temperature, the conduction angles β ₁ and β _{2 of the} 200 V AC power supply waveform supplied to the control heater 22 increase, and more power is supplied to the control heater 22. If the measured temperature of the inert vapor phase 14 is higher than the set temperature, the conduction angles β ₁ and β ₂ are reduced, and the amount of power supplied to the control heater 22 is reduced.
Hardly ever. By controlling the phase of the control heater 22 in this manner, the vapor level is maintained at the best level.

The phase of the electric power supplied to the warming heater 21 is similarly controlled by the current adjusted by the manual control 25 in the waveform of the 200 V AC power supply.

As described above, since the phase controller (thyristor type AC power regulator) 24 controls the phase of the control heater 22 based on the current output amount of the temperature indicating controller 23, the vapor level is very stable and resistant to disturbance temperature changes. . Further, since the heaters 21 and 22 hardly repeat the ON / OFF operation, the life of the heaters and the like is prolonged.

(Effect of the Invention) According to the first aspect of the invention, the power supplied to the heater is phase-controlled by the temperature indicating controller in accordance with the deviation between the measured temperature of the inert vapor phase and the set temperature. Is continuously variably controlled to reduce the fluctuation of the vapor level of the inert vapor phase even if there is a disturbance temperature change,
In addition, since the power supplied to the heater does not suddenly change, the life of the heater or the like can be extended.

According to the second aspect of the present invention, the heater includes a warming heater that supplies a large amount of required heat and a control heater that compensates for the calorific value within the control range, and the power supplied to the warming heater is manually adjusted. Since the power supplied to the control heater is phase-controlled by the temperature indicating controller according to the deviation between the measured temperature of the inert vapor phase and the set temperature,
A stable inert vapor phase can be obtained by the insulated heater, and highly accurate level control can be performed by the control heater.

[Brief description of the drawings]

FIG. 1 is a sectional view and a circuit diagram of a steam tank showing a method of controlling a vapor-phase soldering heater according to the present invention, FIG. 2 is an AC waveform diagram showing phase control of the heater, and FIG. It is sectional drawing. 11 ... steam tank, 12 ... inert liquid, 14 ... inert vapor phase,
21: Heat insulation heater, 22: Control heater, 23: Temperature indicating controller.

Claims (2)

(57) [Claims] In a method of controlling a heater for heating an inert liquid contained in a lower part of a steam tank to form an inert vapor phase for reflow soldering inside the steam tank, electric power supplied to the heater is controlled. A method for controlling a vapor-phase soldering heater, wherein a phase is controlled by a temperature indicating controller in accordance with a deviation between a measured temperature of an inert vapor phase and a set temperature. 2. A method for controlling a heater for heating an inert liquid contained in a lower part of a steam tank to form an inert vapor phase for reflow soldering inside the steam tank, wherein the heater generates a required amount of heat. And a control heater that compensates for the amount of heat generated within the control range. The power supplied to the heater is phase-controlled by manual adjustment, and the power supplied to the control heater is a temperature indicating controller. Wherein the phase is controlled according to the deviation between the measured temperature of the inert vapor phase and the set temperature.