JPH0780077B2 - Feedback Adjustment Method in Weight Control of Molded Parts of Rotary Tablet Machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to setting of each setting device and feedback adjustment of powder filling amount in weight control of tablets of a rotary tablet machine for producing tablets such as pharmaceuticals.

[0002]

2. Description of the Related Art Generally, a molded article such as a tablet is required to have a uniform weight change, but it is difficult to continuously produce a homogeneous molded article due to the physical properties of the powder and the like.

Therefore, in the 1940's, the rotary tablet machine became capable of tableting management by the tablet weight automatic adjusting method based on the deep relationship between the compression load and the tablet weight. The representative ones are listed in the order of publication.

As disclosed in Japanese Examined Patent Publication (Kokoku) No. 45-16085, a change in load applied to a compression roll or a punch during compression molding is converted into a change in electric quantity by an electric strain gauge, and the change exceeds the limit of the electric quantity. The prime mover is activated by the action of the prime mover, and the height of the weight rail moves up and down to enter the die of the lower punch, and the volume of the die is increased or decreased to increase or decrease the powder filling amount and automatically adjust the tablet weight. There is a method of automatically adjusting the weight of a molded product in a powder compression molding machine.

In Japanese Patent Publication No. 55-13839, a change in load applied to a compression roll, a punch, etc. is converted into a potential wave signal by a strain gauge, and the wave signal is converted by a peak value rectifier circuit. By converting into a change of only the maximum potential of the cycle, and the change continuously exceeds a certain limit for a certain number of molded articles set to correspond to a half circumference of the rotating disk,
There is described a method for automatically adjusting the weight of a molded product in a powder compression molding machine in which a pulse motor is operated at a fixed angle and the capacity adjusting means of a die is adjusted by the operation of the pulse motor.

Next, in Japanese Patent Publication No. 55-24400, a pulsating voltage obtained by amplifying a compressive strain generated in a molding portion after electrical conversion is measured by a movable winding type electric meter, and a guideline of the electric meter is provided. A rotary continuous powder molding machine that counts the time of continuously instructing outside the predetermined instruction range by converting it into a multiple of the pulsation cycle of compression strain and adjusting the measuring unit when the count value reaches a predetermined number. The method for automatically adjusting the weight of the molded article in FIG.

Further, Japanese Patent Publication No. 63-39359 discloses a filling device having a rotating filling wheel and a metering wheel whose rotation speed is adjustable, and a height-adjustable metering cam with which an under punch contacts. In a method for manufacturing tablets by means of a tablet press having an electronic measuring device for measuring the pressing force, a minimum pressing force fluctuation is obtained by an electronic control unit which is supplied with signals of the rotation speeds of a filling vehicle and a dispensing wheel. The actual value of the pressing force is compared with the target value, and the tablet weight is readjusted by adjusting the height of the dispensing cam based on the result, and then the rotational speed of the filling vehicle and the dispensing vehicle is adjusted. With the description of the method of manufacturing the tablet, which is adjusted again depending on the measured pressing force,
Further, in the above method, the filling vehicle and the dispensing vehicle are changed in a step manner until the minimum of the pressing force variation is reached, and the filling vehicle and the dispensing vehicle depend on the variation range of the pressing force. Is disclosed, in which a metering cam is adjusted independently by a controller by comparing the actual value with a target value and has a unit for the formation of the average value of the pressing force. The tablet press has a control unit for controlling the rotation speed of the drive unit of the filling vehicle, and the control unit is further connected to the adjusting mechanism of the dispensing cam.

In Japanese Patent Publication No. 3-13958, a change in compression load in powder molding is converted into an electric signal, sampling is performed to calculate a standard deviation, and the standard deviation is calculated to calculate the standard deviation. As a reference value, calculate and set a multi-step set value based on the reference value, and control the amount of powder to be filled, etc. by comparing the electric signal by subsequent molding with each set value. The setting method of the setting device in weight control is described.

[0009]

As described above, various inventions and the like for the automatic adjustment of a large number of tablet weights, the automatic setting of the set value of the setter, etc. have been disclosed. And, all of them show the method of adjusting the powder filling amount so that the compression load returns to the average value of the compression load or the standard deviation value of the compression load when the compression load exceeds the limit of the set value. However, the set value calculated based on the average value or the standard deviation is one numerical value that does not have a width in the mathematical expression, and should be regarded as a point or one line in the diagram, and such a numerical value with no margin Alternatively, if the compressive load is forcibly returned to a point or the like, the overcontrol is generally called, and conversely the weight difference becomes large, so the compressive load is adjusted within the limit of the set value. Therefore, the weight during constant production is within the allowable range, but it is a product that is slightly away from the reference weight, and if the control width is brought close to the average value or standard deviation value, the control value will always be over-controlled and the weight limit If the value exceeds a large value, the discharge amount of defective products may increase.

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

[0011]

The present invention takes the following means in order to achieve such an object. That is, the feedback adjusting method in the weight control of the molded product of the rotary tablet machine according to the present invention converts the change of the compression load in the tablet molding into an electric signal and performs sampling a suitable number of times to calculate the standard deviation of the suitable product. Then, the standard value of the setter is calculated based on this standard deviation, and the set value of each of the multistage setters is set by calculation based on the calculated reference value. In controlling the amount of powder filling, etc. by comparing with each set value, calculate the standard deviation of the compressive load during multiple rotations of the rotary disk during continuous rotary molding, and use this first standard deviation as the reference for the setter. The value is calculated, and the second standard deviation with respect to the compression load in one rotation of the turntable at that time is calculated,
A feedback position having an upper and lower standard deviation width determined based on the second standard deviation with respect to the reference value is provided, and when the compression load exceeds the set value of the setter,
The compression load is controlled and adjusted until the feedback position is reached.

In the above structure, the upper and lower standard deviation width may be determined by multiplying the upper and lower loads of the compressive load by a predetermined coefficient. Further, the feedback position may be provided by multiplying the upper and lower standard deviation width by an arbitrary coefficient.

[0013]

With such a structure, the peak value of the molding pressure (shown in FIG. 2) in powder molding is converted into an electric signal to obtain the standard deviation, and the value is multiplied by a constant coefficient. Then, when the pressure load exceeds the limit of the set value as the set value of each setter, the powder filling amount is adjusted,
The standard deviation of the peak value during one rotation of the rotating disk is calculated, and the peak value higher than the standard deviation value at that time and the peak value lower than the standard deviation value are respectively calculated to calculate the height deviation value of the peak, and the feedback position When the compression load exceeds the set value limit of the setter, the powder filling amount is adjusted until it reaches within the standard deviation width which is the feedback position. By doing so, not only the adjustment within the set value is stopped, but also the adjustment is performed up to the position similar to the standard deviation value of the adjustment limit.

[0014]

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

The reference numeral 4 designates a turntable in which the dies 3 which are molding dies are arranged at equal intervals in the vicinity of the peripheral edge thereof. The upper part of the lower punch 5 is inserted into the die 3 from below, the powder material is filled in the die 3, and the upper punch 2 and the lower punch 5 are pressed by the upper roll 1 and the lower roll 6. Then, the powder in the die 3 is compressed by pressurizing vertically. That is, after the powder is filled in the die 3, the tip of the upper punch 2 arranged above the die 3 of the turntable 4 enters into the die 3, and the upper punch 2 and the lower punch 5 are separated from each other. When passing between the upper roll 1 and the lower roll 6 by the rotation of the turntable 4, the upper punch 2 and the lower punch 5 cause the upper and lower rolls 1,
6 is pressed, which compresses the powder into tablets.

Reference numeral 7 is a load electric converter, and a load cell is typically mentioned. This load-electricity converter 7 includes either the upper roll 1 or the lower roll 6, for example, the upper roll 1.
Is provided so as to be in contact with the support, and its output end is connected to a signal processing device 8 composed of an amplifier or the like to convert a change in compression load in powder molding into an electric signal. The output end of the signal processing device 8 is connected to the setting devices 10, 11, 12, 1 of each stage.
3, 14 and 15, and also to the arithmetic processing unit 9, the arithmetic processing unit 9 samples the maximum peak value of the molding pressure (P _{1 to} P _i shown in FIG. 2). P _n ) to calculate a first standard deviation, calculate a reference value of the setter based on the first standard deviation, and setter 10 of each stage based on the reference value.
Each set value which is the control level of 11, 12, 13, 14, and 15 is calculated and determined.

The arithmetic processing unit 9 not only performs arbitrary sampling before operation, such as when switching product types, but also at regular time intervals, constant molding times, or external arbitrary signals.
Sequential sampling is performed during molding and compression during operation, the first and second standard deviations of the new state can be calculated, and the set value of the marked setter can be automatically reset, and the specified number of times (In the case of this embodiment, the mortar 3 during one rotation
The average load value 16, the maximum load value 17, the minimum load value 18, the first standard deviation 19, the coefficient of variation 20, the second standard deviation 21, etc. can be displayed or recorded and output. The first standard deviation 19 is calculated by sampling the compression load when the turntable 4 continuously rotates and tablets are formed in the meantime. The second standard deviation 21 is a compression load between the upper limit control set value SET3 that sets the upper limit side control start and the lower limit control set value SET4 that sets the lower limit side control start, which will be described in detail below. If there is, the standard deviation of the compressive load during the period in which the turntable 4 rotates once is calculated. In this way, by obtaining the standard deviation of the compressive load during one rotation of the turntable 4, the length dimensional error of each lower punch 5 and the mortar 3
It is possible to detect the variation of the compression load due to the error due to the insertion error into the. This second standard deviation is used to determine the width of the effective region of the feedback position FP set between the upper limit control set value SET3 and the lower limit control set value SET4. Specifically, the effective area width of the feedback position FP is set to a value twice the value of the second standard deviation. When the feedback position FP is set in this way, most of the fluctuation of the compression load generated by one rotation of the turntable 4 is included in the feedback position FP. This feedback position FP is normally automatically
It is set around the reference value when calculating each set value (FIG. 3), and the place where it is larger than the reference value by the value of the second standard deviation becomes the upper limit of the feedback position FP, and similarly, from the reference value. The lower limit of the feedback position FP is a value smaller by the second standard deviation value.

The setter 10 sets the upper limit of the control limit range, and sets the upper limit set value SET1 output from the arithmetic processing unit 9 and the output P which is an electric signal by molding output from the signal processing unit 8. In comparison, when the output P exceeds the upper limit set value SET1, the control signal OUT1 is output.

The setter 11 sets the upper limit exclusion level, and sets the upper limit exclusion set value SET2 output from the arithmetic processing unit 9 and the output P which is an electric signal by molding output from the signal processing unit 8. In comparison, when the output P exceeds the upper limit exclusion set value SET2, the control signal OUT2 is output, and when the number of times the control signal OUT2 is output continues for a predetermined number of times or more, the control is different from the control signal OUT2. It outputs the signal OUT3.

The setter 12 sets the control start on the upper limit side, and the upper limit control set value SET3 output from the arithmetic processing unit 9 and the output P which is an electric signal by molding output from the signal processing unit 8. When the output P exceeds the upper limit exclusion set value SET2, and the number of times the output P exceeds the upper limit exclusion set value SET2 continues for a predetermined number of times or more, the control signal OUT4 is output.

The setting device 13 is the lower limit setting device corresponding to the setting device 12, and similarly, the setting device 14 is the setting device 1
1, the setting device 15 is a lower limit setting device corresponding to the setting device 10, and the above-mentioned upper setting devices 10, 11, 1
The explanation is made by replacing the "upper limit" in the description of 2 with the "lower limit". The input / output signals for the setters 13, 14, 15 are as shown in FIG.
The method of setting the set values in each of the setters 10 to 15 may be the one described in Japanese Patent Publication No. 3-13958.

In the above configuration, when the compression load exceeds the upper limit control set value SET3 or the lower limit control set value SET4 (exceeds the upper limit or falls below the lower limit), it is determined that the compression load is included in the feedback position FP. As described above, the control signals OUT4 and 5 are output to the filling amount adjusting system that controls the weight adjusting mechanism such as a weight rail that determines the height of the lower punch 5 in order to adjust the powder amount filled in the die 3. It With this, when the height of the lower punch 5 is adjusted, the compressive load is gradually increased to the upper and lower limit control set values SET3, SE.
It converges to the region where T4 is the limit. Then, the control further progresses, and the compression load is changed to the feedback position FP.
If included, the operation of the filling amount adjusting system is stopped and the control of the weight adjusting mechanism is stopped. Therefore, after this, since the height of the lower punch 5 is not adjusted, the compression load changes within the feedback position FP, and after a lapse of time, the compression load fluctuates and deviates from the feedback position FP. , Upper or lower limit control set value SET
When 3, SET4 is exceeded, control of the lower punch 5 is started again.

The present invention is not limited to the embodiment described above, and the width of the feedback position FP is set based on the second standard deviation by multiplying the vertical standard deviation width by an arbitrary coefficient. The feedback position FP may be a slightly wider or narrower range. Alternatively, the feedback position FP
The width of is calculated by calculating the standard deviation of the compression load during one rotation of the turntable 4, and calculating the compression load higher than the standard deviation at that time and the compression load lower than the standard deviation, respectively, and obtaining the two compression loads obtained. It is also possible to calculate the difference between the two values and make the value twice the value of the difference.

As another embodiment, FIG. 4 shows an example in which the feedback position FP is deviated from the reference value.
Shown in. That is, by multiplying the upper and lower standard deviation widths by an arbitrary coefficient, the upper and lower standard deviation widths have the same width, and as shown in FIG. 4, the feedback position is below the reference value and the lower limit control set value is set. Set above SET4. Even when the feedback position is set in this way, when the compression load exceeds the upper limit control setting value SET3 or the lower limit control setting value SET4 as in the above embodiment, the compression load is included in the feedback position FP, The amount of powder filled in the mortar 3 is adjusted. However, since the feedback position is deviated to a position below the reference value, that is, a value that is smaller, the weight of the molded tablet is smaller than the reference value within the allowable range, and the consumption amount of the material to be used is reduced as a whole. Can be suppressed.

In addition, the configuration of each part is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0026]

As described in detail above, the present invention provides the standard deviation (first standard deviation) of the compressive load of several revolutions of the rotating disk.
And the standard deviation (second standard deviation) of the compression load in one revolution of the rotating disk when the first standard deviation is calculated, and the former is used to set the set value of the setter and the display is used. It is used for display or recording, and the latter is used for setting the feedback position that temporarily interrupts the control of the amount of powder to be filled, etc. As a result, the weight error with respect to the standard weight during normal production becomes the minimum range, and the number of failures It drastically decreases and contributes to production. Furthermore, if a feedback position based on the standard deviation width is provided, for example, between the reference value and the lower limit control start limit, tablets or the like with a reference weight or less can be produced within the weight regulation, thus saving valuable valuable materials. To do.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view showing an embodiment of the present invention.

FIG. 2 is a waveform diagram of a compressive load of the same example.

FIG. 3 is an explanatory diagram showing a relationship between each set value and a feedback position set around a reference value in the embodiment.

FIG. 4 is an explanatory diagram showing a relationship between each set value and a feedback position set below a reference value in the embodiment.

FIG. 5 is an explanatory diagram showing a relationship between a reference value and each set value in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Upper roll 2 ... Upper punch 3 ... Mortar 4 ... Rotating plate 5 ... Lower punch 6 ... Lower roll 7 ... Load electrical converter 8 ... Signal processing device 9 ... Arithmetic processing device 10, 11, 12, 13, 14, 15 ... Set value 19 ... First standard deviation 21 ... Second standard deviation FP ... Feedback position

Claims (4)

[Claims] 1. A method for converting a change in compressive load during tablet forming into an electric signal, sampling a suitable number of times to calculate a standard deviation of an appropriate product, and calculating based on this standard deviation as a reference value of a setter, Set by calculating and determining each set value of the multistage setter based on the calculated reference value,
In the case of controlling the amount of powder to be filled, etc. by comparing the electric signal by subsequent molding with each set value, the standard deviation of the compressive load during multiple rotations of the rotary disk during continuous rotary molding is calculated, and this first standard is calculated. The standard value of the setter is calculated based on the deviation, the second standard deviation for the compression load in one rotation of the rotating disk at that time is calculated, and the upper and lower standards determined based on the second standard deviation with respect to the standard value. A molded product of a rotary tablet machine, characterized in that a feedback position having a deviation width is provided, and when the compression load exceeds the set value of the setter, the compression load is controlled and adjusted until the feedback position is reached. Feedback Adjustment Method for Weight Control of Robots. 2. The weight of the molded product of the rotary tablet machine according to claim 1, wherein the upper and lower standard deviation width is determined by multiplying the upper and lower loads of the compression load by a predetermined coefficient. Feedback adjustment method in control. 3. A feedback adjusting method in weight control of a molded product of a rotary tablet machine according to claim 1, wherein a feedback position is provided by multiplying an upper and lower standard deviation width by an arbitrary coefficient. 4. A weight control of a molded product of a rotary tablet machine according to claim 1, wherein the feedback position is deviated from a reference value by multiplying an upper and lower standard deviation width by an arbitrary coefficient. Feedback adjustment method in.