JPH0577035A - Reflow apparatus - Google Patents

Abstract

PURPOSE:To obtain a reflow apparatus resisting to the change of conditions and the disturbance by using plural factors, such as N2 flow rate, surrounding temp., number of the revolution of a fan, giving effect to the temp. in the reflow apparatus as the additional factors. CONSTITUTION:Temp. measuring means (1-1) are arranged in a preheating furnace 6, soldering heating furnace 7 and cooling chamber 8 and also an N2 flow rate measuring means (1-2), surrounding temp. measuring means (1-3) and the number of the revolution of the fan measuring means (1-4) are arranged. In a control part 9, a fetching means fetching the measured data as the factor, a tuning means for control rule and a calculating means are arranged. The measured result in the measuring means is fetched into the fetching means as the operational quantity calculating factor and transmitted to the calculating means, and the control rule in the calculating means is inputted into the tuning means. By using a fuzzy control theory with the operational quantity calculating factor, the operational quantity is calculated with the calculating means and by the operational quantity, the temp. control is executed with the control part 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow device in the field of circuit mounting of electronic equipment.

[0002]

2. Description of the Related Art A reflow apparatus applies a cream solder to a printed circuit board on which electronic parts are mounted at predetermined positions, while transporting the printed circuit board by a transporting means in an oxidation preventing atmosphere at a temperature suitable for soldering with the cream solder. Although it is a device that heats up and solders, electronic parts have become smaller and smaller in recent years, and the mounting density of electronic parts on a printed circuit board has gradually increased, and the positional deviation of electronic parts after soldering is tolerable. Since it is becoming smaller, it is necessary to improve the work accuracy of each process. Even with regard to the processing temperature of the reflow equipment, if the heating / cooling speed of the printed circuit board is inappropriate, the solder on the printed circuit board will be even. Does not melt and solidify, but partially melts and solidifies at different speeds before and after, and the miniaturized electronic component is pulled up by the solidification side of the solder and rises, or the position of the electronic component shifts. Problem or cause occurs. Therefore, it is necessary for the reflow device to perform highly accurate temperature control according to the temperature setting designed so that the printed circuit board can be reflowed at an appropriate heating / cooling rate.

The conventional reflow apparatus has various contrivances in its temperature control, and its control method is PID control.

A conventional reflow apparatus using PID control will be described with reference to FIGS. 8 to 10 and equations (1) to (4).

FIG. 8 is a flow chart showing a temperature control operation of a conventional reflow apparatus using PID control.

In step # 11, the temperature measuring means measures the temperature inside the reflow apparatus, and the process proceeds to step # 12.

In step # 12, the taking-in means takes in the measured temperature data in step # 11 as the manipulated variable calculation factor data, and proceeds to step # 14.

In step # 13, the control parameter of the arithmetic expression is input to the arithmetic means in advance by tuning.

In step # 14, the operation means calculates the operation amount from the control parameter input in step # 13 and the operation amount calculation factor data fetched in step # 12 by an operation formula using PID control theory. To do. In this case, when the temperature to be controlled in the reflow device at time n is T _n , the manipulated variable U _n required for temperature control is calculated by the following equation (4).

E _n = T _M −T _n ... (1) ΔE _n = E _n −E _n−1. (2) ΔU _n = I _G × E _n + P _G × ΔE _n + D _G × (ΔE _n + ΔE _n-1 ) ・ (3) U _n = U _n-1 + ΔU _n (4) where, T _M : target temperature E _n : target temperature T _M and measured temperature Deviation from T _n I _G : integral gain of PID control which is a control parameter P _G : proportional gain of PID control which is a control parameter D _G : differential gain of PID control which is a control parameter To calculate ΔU, time integration of ΔE, proportional,
It is called PID control because it uses differentiation. When the above calculation is completed, the process proceeds to step # 15.

In step # 15, the control unit controls the heating element according to the operation amount calculated by the calculating means in step # 14.

FIG. 9 shows an example of temperature control response in the reflow apparatus by the conventional PID control. The measured temperature T _n is controlled according to the target temperature T _M , but it is shown that the control takes a long time and its fluctuation is large. The reason is that in PID control, conditions such as N ₂ flow rate, environmental temperature, fan speed, and thermal conductivity that affect the temperature inside the reflow device are fixed to certain conditions,
The operation amount is calculated using only the temperature to be controlled as the operation amount calculation factor. Therefore, within this certain condition,
A good control result is obtained, but if there is a change in this certain condition, the calculation result does not match the substance, hunting occurs, and the result is as shown in FIG. 9.

FIG. 10 shows an example of the control response of the temperature in the reflow apparatus by the conventional PID control when there is a disturbance (a), and shows that the response to the disturbance is slow. That is, in the PID control, the operation amount calculation formula and its control parameter use the temperature itself in the reflow device as the operation amount calculation factor, and therefore disturbances other than the temperature in the reflow device (for example, changes in N ₂ flow rate, environmental temperature). Change, fluctuations in fan speed, etc.), it cannot react immediately even if the disturbance occurs, and it reacts after the temperature inside the reflow device changes due to that disturbance. It shows that the temperature fluctuations of 1 are inevitable.

[0014]

Therefore, the conventional reflow apparatus in which the temperature is controlled by the PID control has the following problems.

In the temperature control by the PID control, a linear function (the above-mentioned expression (1)) is used as an input (a factor that changes under a certain predetermined condition: a temperature to be controlled in this case) and an output (a manipulated variable). From the formula (4)}, which influences the temperature inside the reflow device, the N ₂ flow rate, the ambient temperature, the fan speed,
The conditions of thermal conductivity and the like fixed to a certain determined conditions, the control parameters compatible PID control function to the fixed condition _{(I G, P G, D} G) defines with, i.e., other than the temperature One control rule in which the changing condition and the dynamic characteristic are fixed is created, and the manipulated variable is calculated from the change of one factor (temperature change in the reflow device). Therefore, there is a problem in that an appropriate manipulated variable cannot be calculated when the above-mentioned certain conditions change, for example, when there is a change in dynamic characteristics such as a change in thermal conductivity at a certain temperature. was there. Also, if there is a disturbance that changes the N ₂ flow rate, environmental temperature, fan speed, and other conditions, the manipulated variable for that disturbance cannot be calculated until the temperature in the reflow device changes due to the disturbance. There was a problem that the response was delayed. Due to these problems, if the temperature inside the reflow device fluctuates as shown in FIGS. 9 and 10, the heating / cooling speed of the printed circuit board becomes unsuitable, as described above, and the printed circuit board is cooled. The solder does not melt and solidify uniformly, but it partially melts and solidifies at different speeds before and after, and the miniaturized electronic component is pulled up by the solidification side of the solder and rises, and the electronic component shifts in position. As a result, defective products are generated.

In order to solve these problems, the present invention does not calculate the manipulated variable mainly by the temperature in the reflow device to be controlled, but N ₂ which affects the temperature in the reflow device. By using multiple factors such as flow rate, environmental temperature, fan speed, etc. as additional factors, N ₂
When the flow rate, environmental temperature, fan speed, etc. change, the appropriate operation amount is immediately calculated for each change, and the N ₂ flow rate is calculated before the temperature change in the reflow device due to those changes occurs. It is an object of the present invention to provide a reflow device which is temperature-controlled so as to cancel the influence of changes in environmental temperature, fan rotation speed, etc., and which is resistant to changes in conditions and disturbance.

Further, in the conventional PID control, the control parameter is divided into an integral term I _G , a proportional term P _G , and a differential term D _G , so the numerical values of these control parameters correspond to the human sense of the machine operator. Not matching, tuning of control parameters is a trial-and-error numerical input for humans,
On-site tuning is difficult and time-consuming, and there is a problem that the human sense of the machine operator cannot be utilized.

In order to solve this problem, the present invention provides
It is an object of the present invention to provide a reflow apparatus which can interactively input and use a human sense of a machine operator as a control parameter.

[0019]

In order to solve the above-mentioned problems, a reflow apparatus of the present invention applies cream solder and carries a printed circuit board on which electronic parts are mounted at predetermined positions while carrying it by a carrying means. In a reflow apparatus that reflows in an antioxidation atmosphere, measuring means for measuring the temperature inside the apparatus and the temperature fluctuation causes such as N ₂ flow rate, environmental temperature, fan rotation speed, etc. that affect the temperature inside the apparatus, and the measurement by these measuring means Incorporating means for taking in at least one of the values as a manipulated variable calculation factor and the manipulated variable calculation factor are divided into a main factor device temperature and other additional factors, and the adaptability is gradually reduced for the additional factors. It is characterized in that it is provided with a computing means for calculating the manipulated variable of the heating element using the fuzzy theory and a control section for controlling the heating element by the calculated manipulated variable.

Further, it is preferable that the tuning of the control rule of the computing means for calculating the manipulated variable of the heating element is an interactive method.

[0021]

[Action] reflow apparatus of the present invention is to use the operation amount calculating the temperature in the reflow apparatus as a main factor is the temperature variations due to changing the temperature in the reflow apparatus, N ₂
Disturbances are included by using the flow rate, ambient temperature, fan speed, etc. as additional factors to control the manipulated variable of the heating element, and by using the fuzzy theory that is robust to changes in dynamic characteristics. Becomes stronger against changes in multiple factors and changes in the dynamic characteristics of factors. This makes it possible to maintain the temperature inside the reflow device at the designed optimum value regardless of changes in conditions, dynamic characteristics, or disturbance. Proper heating of the street
Since the reflow can be performed at the cooling rate, there is no problem that the solder on the printed circuit board is uniformly melted and solidified, and the miniaturized electronic component is pulled up by the solidified side of the solder and rises, or the position of the electronic component is displaced.

Further, since the linguistic control rule (human feeling of the machine operator) is used as the control rule and the control rule can be inputted in an interactive manner, the tuning of the control rule becomes easy and the machine operator can The human sense can be utilized as it is.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, in one embodiment of the present invention, as many factors as possible are used as factors for calculating a manipulated variable for temperature control from among all factors related to temperature changes in the reflow apparatus, and fuzzy logic is used. Calculate the manipulated variable with control theory,
In order to cancel the influence of these factors in advance, and to control the amount of heat generation, the preheating furnace 6, the soldering heating furnace 7, and the cooling chamber 8 are provided with the in-apparatus temperature measuring means (1-1). , N ₂ flow rate measuring means (1-2), environmental temperature measuring means (1-3), and fan rotation speed measuring means (1-4) are provided, and in the prior art, only the internal temperature of the apparatus is used as the operation amount calculation factor. On the other hand, not only is it used to calculate the manipulated variable of the heating element mainly due to the internal temperature of the device, but it is also the operating variable that causes temperature fluctuations such as N ₂ flow rate, environmental temperature and fan speed that affect the internal temperature of the device. It is used for calculation as an additional factor of calculation.
For that purpose, the control unit 9 is provided with an intake means (not shown) for taking measurement data as a factor, a control rule tuning means (not shown), and a calculation means (not shown), and the acquisition means is provided with the above-mentioned means. The measurement result of the measuring means is taken in as a manipulated variable calculation factor and transmitted to the calculating means, and the tuning means is made to input the control rule of the calculating means in an interactive manner (the explanation will be given later), and the calculating means is subjected to fuzzy control by the manipulated variable calculating factor. Use theory to calculate manipulated variables (explained later),
Temperature control in the control unit 9 by the manipulated variable (explained later)
Is being done. The carrier 5 applies cream solder,
A printed circuit board on which electronic components are mounted is carried in and out of the reflow device.

The operation of the temperature control will be described with reference to FIG. 1. In step # 1, the temperature inside the apparatus (1-1) as the main factor for calculating the manipulated variable of the heating element is calculated at predetermined time intervals. (1): Deviation between target value T _M and measured value T _n E _n = T _M −T _n , Expression (2): Deviation change amount ΔE _n
= E _n −E _n−1 is measured by each measuring means. With respect to the N ₂ flow rate (1-2), the environmental temperature (1-3), and the fan rotation speed (1-4) as additional factors for calculating the manipulated variable of the heating element, the formula (1): Target value T _M and measured value T
Each measuring unit deviation E _n = T _M -T _n and _n is measured.

In step # 2, the taking-in means takes in the measurement data of step # 1 as the data of the manipulated variable calculation factor, conveys these data to the computing means, and proceeds to step # 4.

In step # 3, the tuning means inputs a plurality of linguistic control rules (human senses of the machine operator) to the calculating means in advance in an interactive manner as control rules based on the fuzzy theory. The tuning of the control rules by the interactive method is performed as follows.

Control rules based on the fuzzy theory are shown in Tables 1 and 2.
Shown in.

[0029]

[Table 1]

[0030]

[Table 2]

Table 1 is a control rule table for obtaining the manipulated variable depending on the temperature inside the reflow device, which is the main factor, and is the deviation E _n {E _n = T _M -T _n equation (1) of the factor caught by a human ambiguous sensation. } And the amount of change in deviation ΔE _n {ΔE _n = E _n −E _n-1
The control operation amount corresponding to the expression (2)} captured with an ambiguous human sense is shown. The leftmost column of Table 1 shows the factor deviation E _n , and the uppermost column shows the change amount ΔE _{n of the} factor deviation.
Indicates. The characters in the table (referred to as labels) are the amounts captured by a vague human sense in order to represent the operation amount, etc., and indicate the following contents.

[0032] NB = Negative Big NM = Negative Medium NS = Negative Small ZO = Zero PS = Positive Small PM = Positive Medium PB = Positive Big The Table 1 is the linguistic control rules of if-then format, deviations E _n And the change amount ΔE _{n of the} deviation as if
The control rule inside is set to the then. For example, the deviation E _n of measured temperature T _n in the reflow apparatus at time n is NS
If the measured temperature T _n is slightly higher than the target temperature T _M , and the change amount ΔE _n of the measured temperature deviation at that time is NS (slightly decreased), the manipulated variable is the intersection of the above two columns. ZO
(The operation amount is 0).

Table 2 is a control rule table for additional factors such as N ₂ flow rate, ambient temperature, fan speed, etc., which have an influence on the internal temperature of the apparatus. The deviation E _n is if, and the control rule in Table 2 is the
n. For example, the deviation E _n is NS (measurement temperature measured temperature T _n of the environmental temperature at the time n T _n is the target temperature T
_If it is a little higher than _M ), the control amount is NS (lower the amount of heat generation).

Tuning of the control rules in Table 1 by the interactive method is performed as follows. (1) Call and specify the control rule for the operation amount calculation factor. : Characters of the device temperature, N ₂ flow rate, environmental temperature, and fan rotation speed are displayed. For example, the device temperature is designated from among them.

(2) The deviation E _n is called and designated. : P
The characters B, PM, PS, ZO, NS, NM, and NB are displayed. For example, PB is designated from them.

(3) The change amount ΔE _{n of the} deviation is called and designated. : The characters PB, PM, PS, ZO, NS, NM, and NB are displayed, and for example, PB is designated from them.

(4) Call and change the control rule. : A character of the control rule corresponding to the intersection of the PB column of the deviation E _{n and} the PB column of the variation amount ΔE _n of the deviation is displayed, for example, PM, and is changed to, for example, PB.

In this case, the control rule table itself of Table 1 may be displayed on a part of the display panel to check the change result, or Table 1 may be changed directly. With step # 3 completed, the process proceeds to step # 4.

In step # 4, the calculation means uses the fuzzy control theory from the control rule tables 1 and 2 in which the control rules are input in step # 3 and the data fetched in step # 2, and manipulates the heating element. As follows,
calculate.

The fuzzy control means the deviation E _n of each factor for calculating the manipulated variable required for the control.
And the change amount ΔE _{n of the} deviation are replaced with the label captured by the human-ambiguous sensation by the membership function, and the factors replaced by the label captured by the human-ambiguous sensation by Table 1 and Table 2. From the deviation E _n and the change amount ΔE _{n of the} deviation, the operation amount captured with a human ambiguous sensation is obtained, and the operation amount captured with this human ambiguous sensation is quantified by the fuzzy control theory by the membership function. This is a control method of controlling. That is, it is a control method that handles an algorithm that includes an instruction based on an ambiguous linguistic control rule (human feeling of a machine operator).

A membership function as shown in FIGS. 2 and 3 is used as the membership function for the temperature in the reflow device which is the main factor. 0 on the horizontal axis is the standard value of the factor,
1 indicates the upper limit value of the fluctuation range for controlling the factor, -1 indicates the lower limit value of the fluctuation range for controlling the factor, and the value within the fluctuation range of the factor is converted between 1 and -1. .. In this case, the values above the upper limit are all 1 and the values below the lower limit are all -1. The vertical axis represents the goodness of fit (from 0 to 1). When the measured value of each factor is applied to the horizontal axis of this membership function, the intersection of this measured value and each label NB, NM ... PB of the membership function is the goodness of fit of the label.

A membership function as shown in FIG. 5 is used as a membership function for N ₂ flow rate, environmental temperature, fan rotation speed, etc., which are additional factors. The membership function has a degree of conformity gradually reduced depending on the degree to which the additional factor affects the temperature in the reflow apparatus, but the usage method is the same as that in FIGS. 2 and 3.

The operation amount for the main factor is obtained as follows.

First, the label of the measured value and the goodness of fit are obtained. The deviation E _{n of the} temperature inside the reflow apparatus and the variation ΔE _n of the deviation, which are the main factors, measured in step # 1 are replaced with the horizontal axis of the membership function in FIG. As a result, the deviation E _n becomes NM with a goodness of fit of 0.8 and NS with a goodness of fit of 0.2, and the change amount ΔE _{n of the} deviation becomes PM with a goodness of fit of 0.8 and PS with a goodness of fit of 0.2. Become.

Next, the label of the manipulated variable and the goodness of fit are obtained from the label of the measured value and the goodness of fit. The labels for the above measurements are applied in Table 1. NM and N of deviation E _{n in} Table 1
And column S, adaptability 0.16 at the intersection of the column of the PM and PS variation Delta] E _n of the deviation NB of (a product of fit of the variation Delta] E _n of the deviation E _n and deviation. Hereinafter the same) , Goodness of fit 0.04
NM, goodness of fit O. 64 NB, goodness of fit O.S. 16 NB
Is the deviation E _{n of the} temperature in the reflow equipment and the change amount ΔE _{n of the} deviation.
They are the labels of the manipulated variables for and and the goodness of fit. The total of these is the label of the manipulated variable and the goodness of fit which are captured with a vague sense of humanity, and is the NB having the goodness of fit of 0.96 and the NM having the goodness of fit of 0.04.

Further, the label and the degree of conformity of the operation amount captured by the human ambiguous feeling are applied to the membership function of FIG. 6 which digitizes the operation amount captured by the human ambiguous feeling. As shown in FIG. 6, the goodness of fit of the NB is 0.96.
The abscissa value of the center of gravity A, which is a combination of both the area below and the area with a goodness of fit of 0.04 or less, is a numerical value used for calculating the manipulated variable for the main factor, and thereby the fuzzy control theory Calculate the manipulated variable numerically. The manipulated variables quantified as described above are obtained for all the temperature measurement values in the reflow apparatus.

The operation amount for the additional factors such as the N ₂ flow rate, the ambient temperature and the fan rotation speed is added to the numerically manipulated operation amount for the main factor as follows.

First, for example, with respect to the ambient temperature measured in step # 1, the deviation E _n is replaced with the horizontal axis of the membership function of FIG. As a result, the deviation E _n becomes a PS with a goodness of fit of 0.17 and a PM with a goodness of fit of 0.07, which are captured by an ambiguous human sense.

Next, the PS having a goodness of fit of 0.17 and the PM having a goodness of fit of 0.07 in the control rules corresponding to these in Table 2 are the manipulated variables which are captured by a human ambiguous sensation.

Further, the operation amount captured by the human ambiguous sensation is applied to the membership function for digitizing the operation amount captured by the human ambiguous sensation of FIG. As shown in FIG. 6, the horizontal axis value of the center of gravity B obtained by combining both the area with PS goodness of fit of 0.17 or less and the area of PM goodness of fit with 0.07 or less is used to calculate the operation amount for this additional factor. Numerical value to be used, which is used to find the numerically manipulated variable in fuzzy control theory. For all of the additional factors, the operation amount quantified as described above is calculated.

Finally, the horizontal axis value of the center of gravity C obtained by combining the center of gravity A of the main factor and the center of gravity B of all the additional factors is obtained. From the value of the horizontal axis of the center of gravity C, the total manipulated variable for the main factor is calculated by the fuzzy theory. In this way, the total manipulated variables of all main factors are calculated. When step # 4 ends, the process proceeds to step # 5.

At step # 5, the control section 9 controls the heating element by the total operation amount calculated by the calculating means at step # 4. In this case, the temperature inside the reflow device is measured, and that temperature is the main factor for calculating the manipulated variable.In addition to this main factor, the temperature variation cause that affects the temperature inside the reflow device is an additional factor for calculating the manipulated variable. Since the temperature control condition is calculated and set by using as above, even if some condition changes and the dynamic characteristic of the temperature inside the reflow device changes, even if a plurality of additional factors change or there is a disturbance, The preheating furnace 5 is maintained at an optimum temperature for preheating, the soldering heating furnace 7 is maintained at an optimum temperature for soldering, and the cooling chamber 8 is maintained at an optimum temperature for cooling.

By comparing and examining the variation record of the main factor, the variation record of the additional factor, and the temperature control response result record, it is possible to judge the suitability of the control rule table. Can be called to interactively modify the control rule table as described above. By accumulating this experience, the machine operator can sequentially understand which rule works and to what extent, so that the control rule table can be appropriately modified and the control level can be improved.

FIG. 7 shows an example of the temperature control result in the reflow apparatus of the above embodiment. The vertical axis represents the temperature inside the reflow apparatus, the horizontal axis represents time, and the broken line represents the target temperature T _M. FIG. 7 shows that the reflow apparatus of the present invention can sufficiently reduce the difference from the target temperature T _{M in} a short time and perform accurate control.

The present invention is not limited to the above-mentioned embodiment, but various modes are possible. For example, the measurement position and number of the temperature in the reflow device, which is the main factor, are arbitrary. N ₂ flow rate as an additional factor,
The number of means for measuring the environmental temperature and the fan rotation speed is arbitrary.
The additional factors are not limited to the above, and other factors such as the type of the printed circuit board and the processing amount can be added as additional factors. The shape of the membership function can be freely designed according to the degree of influence of the factor. The rate of decrease of the adaptability of the additional factor can be freely designed depending on the degree of influence of the additional factor. In the present embodiment, the main factor control rule table is two-dimensional and the additional factor control rule table is one-dimensional, but not limited to this. Further, the method of inducing the numerical value by the control rule or the membership function is not limited to the method of the embodiment.

[0056]

The reflow apparatus of the present invention takes in at least one of the internal temperature of the reflow apparatus and the measured value of the measuring means for the cause of temperature fluctuation that affects the internal temperature of the reflow apparatus as a factor for calculating the manipulated variable for temperature control. And the operation amount calculation factor is divided into a main factor and an additional factor which is used by gradually decreasing the degree of conformity, and the operation amount of the heating element for the factor is calculated using the fuzzy theory based on linguistic control rules and membership functions. It is possible to provide a reflow device that is resistant to changes in dynamic characteristics and disturbance due to the provision of the calculation means. As a result, even if electronic components are miniaturized and the mounting density of printed circuit boards is getting higher, the temperature control of the reflow equipment is effective against changes in multiple factors including disturbance and changes in dynamic characteristics of factors. It becomes stronger and the temperature inside the reflow equipment can always be maintained at the designed proper value, and the printed circuit board can be reflowed at an appropriate heating / cooling rate, so the solder on the printed circuit board is melted and solidified uniformly, It is possible to prevent production of a miniaturized electronic component which is pulled by the solder which solidifies, and to prevent the position of the electronic component from being displaced, and it is possible to manufacture a high-quality product with few defects.

Further, since the linguistic control rule is used, the control rule of the arithmetic means can be tuned in an interactive manner, the conventional trial-and-error tuning is eliminated, and the time required for tuning is reduced. Play.

Further, since the linguistic control rules can be input, the experience and knowledge of the machine operator can be input as they are, and not only the tuning becomes simple, but also the machine operator sequentially determines which rule works and to what extent. By being able to grasp it, there is an effect that the control level can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a reflow apparatus according to an embodiment of the present invention.

FIG. 2 is an example of a membership function used for fuzzy control in FIG.

FIG. 3 is another example of a membership function used for fuzzy control in FIG.

FIG. 4 is an example of replacing a measured value with a label and a goodness of fit which are captured by an ambiguous human sense by a membership function of a main factor.

FIG. 5 is an example of replacing a measured value with a label and a goodness of fit which are captured by an ambiguous human sense by a membership function of an additional factor.

FIG. 6 is an example of digitizing an operation amount captured with a vague sense of humanity by a membership function.

FIG. 7 is an example of a temperature control result of the embodiment of FIG.

FIG. 8 is a flowchart of a conventional temperature control operation.

FIG. 9 is an example of a temperature control result of a conventional example.

FIG. 10 is another example of the temperature control result of the conventional example.

[Explanation of symbols]

1-1 In-apparatus temperature measuring means 1-2 N ₂ flow rate measuring means 1-3 Environmental temperature measuring means 1-4 Fan rotation speed measuring means 5 Conveying means 6 Preheating furnace 7 Soldering heating furnace 8 Cooling chamber 9 Control section

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Claims (2)

[Claims] 1. A reflow device for reflowing a printed circuit board, to which a solder paste is applied and an electronic component is mounted at a predetermined position, in an oxidation preventing atmosphere while being carried by a carrying means. Measuring means for influencing the temperature of N ₂ flow rate, environmental temperature, fan rotation speed, etc., and at least one of the values measured by these measuring means
Of the operation amount calculation factor and the operation amount calculation factor described above are divided into the main factor internal temperature of the device and other additional factors. A reflow apparatus comprising: a calculation unit that calculates a manipulated variable of a heating element using a fuzzy theory; and a control unit that controls the heating element based on the calculated manipulated variable. 2. The reflow apparatus according to claim 1, wherein the tuning of the control rule of the calculation means for calculating the manipulated variable of the heating element is an interactive method.