JPH05143177A - Operating device for furnace - Google Patents

Abstract

PURPOSE:To eliminate the necessity of complicated pattern setting work relating to the manipulated variables of temperature, pressure, and so on. CONSTITUTION:A microcomputer 6 calculates manipulated variables I, P based upon a deviation epsilon between control variables x, w measured by a measuring instrument 4 and objective values x p, wp set up by a setter 5 and outputs control signals s1, s2. In this case, the microcomputer 6 sequentially stores the calculated manipulated variables I, P in a memory 6c, and thereafter executes memory playback control based upon the stored data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace operating device which is effective for properly performing dewaxing or sintering.

[0002]

2. Description of the Related Art In the dewaxing process, the sintering process, etc., it is extremely important to change the size and weight of the sample stored in the furnace in a certain pattern over time in order to obtain a high quality final product. It is considered important. However, in the past, it was extremely difficult to measure the size and weight of the sample once stored in the furnace during processing. Therefore, the method of feedback control of temperature, pressure, etc. to realize an ideal sample change pattern was adopted. It was not possible to do so, and depending on experience and feeling, the temperature and pressure that were considered desirable were specified in correspondence with the passage of time.

[0003]

However, as long as the method is relied upon, the change pattern of dimensions and the change pattern of furnace temperature must be associated with each other by trial and error for each different sample. Therefore, a great deal of labor and time are required for the pattern setting work, resulting in a problem that the operation efficiency and the product cost are enormously adversely affected. Further, even if feedback control is performed, a sample for measurement must be prepared for each treatment, and the effective space in the furnace is reduced.

An object of the present invention is to effectively solve such a problem.

[0005]

The present invention adopts the following constitution in order to achieve the above object.

That is, the furnace operating apparatus according to the present invention is
As shown in FIG. 1, a measuring means b for measuring the controlled variable in the furnace a, that is, the dimension x and the weight w of the sample A, and an ideal time change pattern of the controlled variable x, w, etc. are set. The target value setting means c, and the deviations ε between the target values x _p , w _p given by the target value setting means c and the controlled variables x, w actually measured by the measuring means b are obtained and converged to zero. A control means d for calculating the manipulated variable such as the temperature T and the pressure P by a method such as multiplying the gain G and outputting the control signals s ₁ , s _{2 and the} like, and a control signal input from the control means d The operation means e ₁ , e ₂ etc. for realizing the operation quantities T, P etc. corresponding to s ₁ , s ₂ etc. and the operation quantities T, P etc. calculated by the control means d are held as a temporal processing pattern. And a storage unit f for storing the control unit d in the storage unit f. It is characterized in that the processing pattern is taken out and the control signals s ₁ , s _2, etc. can be output again.

In order to accurately measure the size and weight of the sample contained in the furnace, it is effective to construct the measuring means based on a method called a dynamic measuring method. As the measuring means adopting this dynamic measuring method, a receiving frame for holding the sample on the upward surface, and a supporting portion on which the receiving frame is placed,
A probe which is disposed so as to be relatively displaceable between the receiving frame and the sample and separates the receiving frame from the lifting support together with the sample, and a probe upper end portion when the probe is relatively displaced between the sample and the receiving frame without lifting the receiving frame. It comprises a displacement detecting means for detecting the relative displacement amount and a weight detecting means for detecting the weight applied to the upper end of the probe when the probe lifts the receiving frame. At the same time, it is possible to obtain the amount of change in weight.

[0008]

With such a structure, the target value setting means c merely sets an ideal time change pattern of the controlled variables x, w, etc., and the control means d causes the ideal time change. The pattern will be executed automatically. That is, after the sample A is housed in the furnace a and the treatment is started,
At a certain time, the controlled variables x, w, etc. are the target values x _p , w _p
When the values deviate from the above, the control means d calculates the manipulated variables T, P, etc. that cause the deviation ε to converge to 0 by the comparison calculation function, and the corresponding new control signals s ₁ , s.
_2nd magnitude will be output. Therefore, in this apparatus, even if the pattern of the manipulated variables T, P, etc. is not artificially set, the controlled means x seeks the pattern, and the controlled variables x, w etc. are always set to the target values x _p , w _p or their vicinity. Feedback control will be performed on the value of.

Moreover, the operation amount T calculated by the control means d,
The processing pattern such as P is held by the storage means f, and the control means d is configured to be able to re-output the control signals s ₁ , s ₂ etc. in accordance with the processing pattern in the storage means f. Therefore, the difference in the type and amount of sample A handled,
Alternatively, as long as the aging of the furnace a is within the range that does not impair the reproducibility of control, this device does not require feedback control again, and the sample A for measurement, the measuring means b, the target value setting means c and the control It is possible to perform the open loop control by removing the comparison calculation function part in the means d.

[0010]

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

The furnace a is constructed so as to be able to perform dewaxing and sintering, for example, and the heater 1 for heating the object to be processed A arranged in the furnace a and the heater 1 are energized. It is provided with a temperature controller 2 as an operating means, and a pressure controller 3 as an operating means for controlling the flow rate in the inlet / outlet passage of the in-furnace gas, the processing gas and the like. In such a furnace a, the present embodiment provides an operating apparatus including a measuring device 4 as a measuring device, a setting device 5 as a target value setting device, and a microcomputer unit 6 serving as a control device and a storage device. Applied.

The measuring device 4 is for measuring the dimension x and the weight w of the sample A, which are the controlled quantities of the furnace 1, in real time. For example, the present inventor proposes Japanese Patent Application No. 3-63590.
The one proposed in No. 1 is applicable as appropriate. As shown schematically in FIG. 3, the structure is such that a receiving frame 41 for holding the sample A on the upward surface 41a, a sample table 41b also serving as a temperature compensating table, and a supporting section on which the receiving frame 41 is placed. 42, a probe 43 disposed between the receiving frame 41 and the sample A so as to be relatively displaceable, and capable of separating the receiving frame 41 together with the sample A from the lifting support portion 42.
Displacement detecting means 44 such as a magnescale for detecting the relative displacement amount of the probe 43 when the receiving frame 41 is relatively lifted without raising the receiving frame 41, and the upper end of the probe 43 when the probe 43 raises the receiving frame 41. And a weight detecting means 45 such as a load cell for detecting the weight applied to the part. Then, the dimension x of the sample A is obtained by subtracting the relative displacement amount detected by the displacement detection means 44 from the relative displacement amount (maximum variable amount) measured when the sample A does not exist, and the weight detection means 45 detects it. From the weight to be sample A
Sample A by subtracting the weight in the absence of
The weight w is calculated.

Further, the setting device 5 sets how it is desirable that the dimension x and the weight w of the sample A change temporally with the start of processing. For example, in dewaxing, if degreasing progresses rapidly, defects such as cracks will occur in the final product, so it is necessary to gradually reduce the weight w.
Further, in the sintering process, when the sintering progresses rapidly, defects such as cracks still occur in the final product, so it is necessary to gradually reduce the dimension x. Taking these conditions into consideration, a time chart of a time change pattern is prepared. The time chart shows the microcomputer unit 6
Stored in the memory 6c.

The microcomputer unit 6 includes a CPU 6a and an interface 6b in addition to the memory 6c.
The main control program is stored in the memory 6c, and in accordance with the program,
The deviation between the target values x _p , w _p given by the setting device 5 and the controlled variables x, w actually measured by the measuring device 4 is obtained at a constant cycle time, and the deviation ε is eliminated by multiplying it by an appropriate gain. The control values are calculated so that the possible manipulated variables T and P are calculated and output to the temperature controller 2 and the pressure controller 3 as control signals s ₁ and s ₂ , respectively. In addition, the program sequentially stores the manipulated variables T and P in other areas of the memory 6c each time the manipulated variables T and P are calculated. On the other hand, the control signal s
_The temperature controller 2 to which ₁ is input amplifies the signal s ₁ to supply the drive current I to the heater 1, and the pressure controller 2 to which the control signal s ₂ is input, outputs the signal s 1.
_{By 2 the} electromagnetic valve etc. is operated to achieve a predetermined valve opening.

After the data for one charge is collected through the above-mentioned processing, the microcomputer unit 6 uses another simpler auxiliary control program to obtain those data, that is, the manipulated variable T, A so-called memory playback operation in which P is sequentially taken out from the memory 6c and the control signals s ₁ and s ₂ are output to both the controllers 2 and 3 can be performed.

With such a configuration, the setting device 5
In the above, by simply setting an ideal time change pattern of the controlled variables x, w, etc., the microcomputer unit 6
Will automatically control the ideal time change pattern. Therefore, the pattern setting work relying on the conventional experience and feeling is unnecessary, and as a result, it is possible to improve the operating efficiency and yield of the furnace and reduce the product cost. Moreover, once the data is collected, the microcomputer unit 6 can play back the same processing, so that the reproducibility of control is not impaired by the difference in the type and amount of the sample A to be handled, the secular change of the furnace a, or the like. As far as it can be considered, this device does not require feedback control again for the same process. Therefore, for a manufacturer who repeatedly manufactures a large number of sintered products of the same standard repeatedly, the sample A, the measuring device 4, and the setting device 5 are unnecessary, and only the auxiliary program is installed in the microcomputer 6. It becomes possible to ship, and the cost of the operating device itself can be reduced, and the space factor and effective space in the furnace can be improved by downsizing the device.

In the above embodiment, the dimension x and the weight w of the sample A are targeted as the controlled variables, but only one of them may be targeted, or another controlled variable may be targeted.
The same applies to the manipulated variable. In the above embodiment, the temperature T and the pressure P are targeted, but either one or other manipulated variables may be targeted. Other controlled amounts include, for example, in-reactor partial pressure required for the reactive gas in the field of reactive sintering where sintering is performed while introducing the reactive gas into the furnace. Other configurations can be variously modified without departing from the spirit of the present invention.

[0018]

Since the furnace operating apparatus according to the present invention has the above-described structure, the control means can set an ideal time change pattern of the controlled quantity only by setting the ideal time change pattern. It will be carried out automatically. for that reason,
The control amount can be feedback-controlled to the optimum value without artificially setting the operation amount pattern, and the operation efficiency and the yield can be improved, and the product cost can be reduced. Moreover, since the control means can perform open loop control according to the once-collected processing pattern, when repeating the same processing, it is possible to remove some of the constituent elements of the apparatus and implement it, thus reducing the cost of the apparatus itself. Also works well.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the configuration of the present invention.

FIG. 2 is a system diagram showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a measuring instrument used in the same example.

A ... sample a ... furnace b ... measuring means c ... target value setting means e _1, e ₂ ... operating means f ... memory means P ... operation amount [Description of symbols] (pressure) s _1, s ₂ ... control signal w ... control amount (weight) x ... control amount (dimension) x _p, w _p ... target value T ... manipulated variable (temperature) epsilon ... deviation 2 ... operating means (temperature controller) 3 ... operating means (pressure controller) 4 ... measuring means (Measuring device) 5 ... Target value setting means (setting device) 6 ... Control means (microcomputer unit) 6c ... Storage means (memory)

Claims (1)

[Claims] 1. A measuring means for measuring a variation of a sample, a target value setting means for setting an ideal time variation pattern of the variation, a target value given by the target value setting means and the measuring means. Corresponds to control means for obtaining a deviation from the actually measured change amount, calculating a manipulated variable such as temperature and pressure that converges it to zero, and outputting a control signal, and a control signal input from this control means. And a storage unit for storing the operation amount calculated by the control unit as a temporal processing pattern, wherein the control unit stores the process stored in the storage unit. An apparatus for operating a furnace, wherein the pattern is taken out and a control signal can be output again.