JPS6045039B2 - Abnormality monitoring method in powder molding press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for monitoring abnormalities in a powder compacting press.

I guess L--After measuring the dimensional accuracy of each part of the finished product,
It was determined by measuring the density.

That is, first, the dimensions of each part of the molded product removed from the press machine are measured using a micrometer or other measuring device, and it is confirmed that the dimensions are within tolerance.

Then, after dividing the molded article into several parts and measuring the weight of each divided piece, each divided piece was mixed with a liquid (with a specific gravity of 1) (
The weight is measured again in water (water, etc.), and the difference from the measured value is the density of each divided piece.If the density is within a predetermined tolerance range, it is considered to be a good product. In this way, it takes time to determine whether the product is good or bad, and if the press is stopped during this time, the operating rate will decrease, and if the work continues, it may result in a series of defective products.

Moreover, since the density of each piece cannot be determined unless the molded product is divided, there are problems in terms of productivity and quality assurance, such as the inability to perform 100% inspection or frequent sampling inspections, and improvements have been desired. 1
Therefore, the present invention focuses on the fact that the pressure that the die, each punch, etc. receives from the molded product when molding is completed is approximately proportional to the density of each molded part, and the pressure that the die, each punch, etc. receives from the molded product during molding, The thickness and dimensions of each part of the molded product after molding are measured, and these measured values are compared with the received pressure and dimension values of preset standards. Based on the results of this comparison, the quality of the molded product is judged, and the tolerance is determined. A method that can improve productivity and ensure quality by promptly performing necessary processing such as stopping the press machine, issuing an alarm, or issuing correction commands to each part of the press machine when the value exceeds the value. The purpose is to provide the following.

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a central vertical cross-sectional view showing the main parts of a mechanical powder press machine. Listing the names and functions of each part, 1 is a drive source for the press machine that is connected to a not-shown handwheel and rotates. A main shaft 2 is an upper ram that moves up and down along the inner wall of the frame 3. 4 is a connecting rod 5 is an arm which converts the rotational motion of the main shaft 1 into linear motion and moves the upper ram 2.
Intervene to communicate.

An upper punch 7 is attached to the lower surface of the upper ram 2 via an upper punch pressure sensor 6 for measuring the pressure received by the upper punch. On the other hand, a die 9 attached to a die plate 8 is provided below the upper punch 7, and an outer punch 10, an inner punch 11, and a core rod 12 are inserted into the central through hole of the die 9 from below. They are arranged in such a manner that they can be fitted into each other, and these are formed so as to press the raw material powder and press-mold the molded product A by cooperating with the upper punch 7 which is fitted from above the central through hole. First, the outer punch 10 is attached to the punch plate 13 via the outer punch pressure sensor 14, and the punch plate 13 is provided with an insertion hole for the busher 15 vertically disposed on the die plate 8! be. Next, inner punch 1
1 is attached to a base plate 17 mounted on the frame 3 via an inner punch pressure sensor 16, and a slide block 18 is placed on the base plate 17.

A roller 18a is attached to the slide block 18, and the roller 18a slides left and right on the base plate 17 while rotating under pressure from the inclined piece 15a of the busher 15 during the knockout process.
As a result, the punch plate 13 that was supported until the 4th stage of the compression process
Since the bottom position of the die plate 8 shifts from the convex surface 13a to the flange surface 13b, the die plate 8 can be further lowered, and the molded product A can be easily knocked out. Furthermore, core rod 12
The lower end of the yoke plate 19 is screwed onto a yoke plate 19, and although a portion of the yoke plate 19 is omitted, it is connected to the die plate 8 via a guide rod 20, and this yoke plate 19 is connected to the die plate 8 via a core pressure sensor 21. Although not shown, it is attached to a lower ram 22 that is movable up and down by the drive of a hydraulic cylinder or the like. Each of the pressure sensors 6, 14,
16 and 21 are devices that receive pressure with a bellows or diaphragm, etc., and convert it into an electrical signal by changing inductance, capacitance, resistance, etc. due to the mechanical displacement that occurs.For example, the piezoresistive effect of a strain gauge or semiconductor element is used. A known sensor such as a diffusion type semiconductor pressure sensor that utilizes resistance change is used.

Note that instead of the pressure sensor 14 that measures the pressure received by the outer punch 10, a pressure sensor 1 is installed on the bottom surface of the punch plate 13.
4X is replaced with a pressure sensor 16 that measures the pressure received by the inner punch 11, a pressure sensor 16X is installed on the lower surface of the base plate 17, a pressure sensor 21X is installed on the guide rod 20, and a pressure sensor 21X is installed on the guide rod 20 instead of the core rod pressure sensor 21. Good too. Next, FIG. 2 shows an automatic dimension measuring device, which is attached to a measuring table 3a which is integral with the frame 3 and forms the same plane as the die table 8, adjacent to the knockout position of the press machine. ing.

Hydraulic cylinders 23, 2 are installed at the upper and lower positions of the measurement table 3a.
4, and the pistons 23a, 24a of each hydraulic cylinder.
The tips of the measuring table 3a are screwed to an upper slide plate 25 and a lower slide plate 26 arranged above and below the measurement table 3a, respectively.

And upper slide plate 25 and lower slide plate 26
are vertically slidably fitted via sliding members to the guide posts 27 and 28 which are installed in an upright state through the measurement table 3a, and the upper and lower slide plates 25,
Magnetic sensors 29a, 29b, 29c and opposing magnetic sensors 30a, 30b, 30c are mounted on the magnetic sensor 26 at intervals suitable for each part of the molded product whose dimensions are to be measured. On the other hand, the knocked-out molded product A on the die table 8 is extruded by a feeder (not shown) and sequentially transferred onto the adjacent measurement table 3a.
A is provided with a guide groove 31 for guiding to the measurement position, and the bottom of the guide groove at the measurement position where the magnetic sensor is disposed and protrudes from each other is provided with through holes 31a, 31 through which each magnetic scale is inserted.
b, 31c are each drilled.

In the above embodiment, a well-known magnetic sensor such as Magnescale (trade name of Sony Magnescale Co., Ltd.) was used as a dimension detection sensor. Various dimension detection sensors developed in recent years, such as meters, can be used.

Next, although not shown in the drawings, the main shaft 1 is equipped with various rotary cam switches in order to perform predetermined drive control for each movable part as in a normal press machine. A rotary cam switch S1 for commanding received pressure measurement is installed so that each of the pressure sensors can be activated and a measured received pressure signal can be taken out when molding is completed when the main shaft has rotated 180 degrees.

Similarly, in order to measure the dimensions of each part of the molded product A that has been successively knocked out after molding at a predetermined timing in relation to the breath cycle, when the molded product A is transferred to the measurement position where the magnetic sensor is installed, the hydraulic cylinder 23 , 24 to measure the dimensions of each part with a magnetic sensor, and a rotary cam switch S2 for dimension measurement command so that when the main shaft 1 has rotated 180 degrees, each magnetic sensor is activated and a measured dimension signal can be taken out. is installed. Next, FIG. 3 is a block diagram showing the configuration for processing each of the measurement signals, and the following description will be made based on this block diagram.

First, when the breath is started and the rotary cam switch S1 for receiving pressure measurement command is closed when the main shaft 1 rotates 180 degrees, the pressure sensors 6, 16, 2
, 14 measure the received pressure of the upper punch 2, inner punch 111, core rod 12, and outer punch 10 during molding, and generate the respective measured received pressure signals Pa, Pb, Pc,
Pd are each input to a comparator.

Then, in the comparator, each standard received pressure signal P from the standard received pressure setting device is calculated in advance or set based on past data.
As, Pbs, Pcs, and Pds are compared to determine whether or not they are within the allowable range.

On the other hand, for a molded product that has been knocked out after molding, when the dimension measurement command rotary switch S2 is closed, the hydraulic cylinders 23 and 24 are activated, and the magnetic sensors 29a and 29
As the upper slide plate 25 with the magnetic sensors 30a, 30b, and 30c attached thereto descends, the lower slide plate 26 with the magnetic sensors 30a, 30b, and 30c attached rises, and the dimensions are measured when each sensor comes into contact with each measuring part of the molded product. Measurements are taken.

In this case, as shown in FIG.
The sum of the measurement signal a1 of a and the measurement signal A2 of the magnetic sensor 30a, the thickness L2 is the sum of the measurement signal E of the magnetic sensor 29b and the measurement signal ■ of the magnetic sensor 30b, and the thickness L is the measurement signal of the magnetic sensor 29c. Measurement signal of signal C1 and magnetic sensor 30c. By adding the measurement signals from each magnetic sensor using a computing unit, measurement dimension signals La, Lb, and IJ corresponding to the respective thicknesses Ll, L2, and L3 are obtained, respectively. Each of these measured dimension signals is then given to a comparator (comparator) in the same way as the measured received pressure signal, and is compared with a reference value preset in the standard dimension measuring instrument to determine whether or not it is within the allowable range. be done.

Note that instead of the rotary cam switches Sl and S2, a rotary encoder or the like which generates predetermined pulses corresponding to the angular position may be mounted on the main shaft 1, and each sensor may be actuated by the generated pulses. Further, as the standard receiving pressure setting device and the standard dimension setting device, digital switches can be used to change the settings arbitrarily, or a memory circuit used in a microcomputer or the like can be used.

The comparison data results of the received pressure and dimensions are each sent to the next stage timing setter, but in this case, the dimension measurement is delayed by several breath cycles compared to the received pressure measurement.
The timing setter is used to match this delay.

In other words, a circuit that temporarily stores data, such as a shift register, is used, and the comparison result data from dimension measurements is immediately sent to the next stage, but the comparison result data from received pressure measurements are stored in one stage and sequentially sent to the next stage. The data is shifted and sent to the next-stage first output device and nine information analysis processors at the same timing as the comparison results obtained by measuring the dimensions of the same molded product.

Incidentally, a timing setter may be placed before the comparator, and after matching the timing of each measurement data, the data may be compared with the reference value.

The first output device issues an alarm or a stop command to the breather based on the comparison results. In this case, an 0R circuit can be used to activate when one of the values deviates from the standard value, or it can be combined with an AND circuit to activate when multiple data outside the tolerance range are present.
Weighting is applied to each measurement location, and in combination with a counter or the like, an appropriate circuit configuration is configured such that the circuit operates when data outside the allowable range occurs for each location. In addition, the information analysis processor includes a memory circuit,
It has built-in arithmetic circuits, control circuits, etc., and is programmed with data for various molded products in the press machine, data that instructs the movement of each necessary movable part, and correction data in case they deviate from standard values. There is.

When the comparison result data is sequentially input, the data is stored as new accumulated data, and information analysis including calculations is performed with preset program data, and upper punch and other operations are performed as necessary. A command is given to the press machine via the second output device in the next stage to appropriately correct the movement of the movable part, the amount of material to be filled, etc. In this way, the abnormality monitoring method of the present invention detects the pressure that the die, each punch, etc. receive during molding, and automatically measures the dimensions of each part of the knocked-out molded product in sequence after molding. These measured receiving pressures and dimensions are set in advance and sequentially compared with standard values to determine the quality of the molded product. If an abnormality occurs such as exceeding the allowable value, an alarm is immediately issued or the press machine is activated. It gives a stop command and also gives a correction command to the press machine.

In other words, we focused on the fact that the pressure that a die, punch, etc. receives from a molded product when molding is completed is approximately proportional to the density of the molded product.
By automatically measuring this receiving pressure during pressing and comparing it with the standard receiving pressure, it is possible to detect the uniformity of density in each part of the molded product and deviations from the three standard values.

In addition, the dimensions of each part of each molded product pressure-formed under the above-mentioned receiving pressure are automatically measured after being knocked out, and these dimensions are compared with standard values, and information regarding these dimensions and the above-mentioned receiving pressure is also obtained. 4.Adjust the time difference during the press cycle with the information (for example, temporarily store the received pressure information for several cycles of the breath and retrieve it at a timing that matches the dimensional information). For each molded product, the received pressure and dimension information are sequentially retrieved as comparison results, and the comparison results are compared with various program data stored in advance in the information analysis processor. The idea is to determine whether a molded product is good or bad by analyzing the information. Therefore, the quality of the molded product can be determined immediately after molding, so there is no need to stop the press until the determination results are obtained, which would lower the operating rate or produce a number of defective products, as was the case in the past. Productivity and quality. This is an extremely effective abnormality monitoring method for ensuring quality.

[Brief explanation of the drawing]

The drawings all show embodiments of the present invention; Fig. 1 is a vertical cross-sectional view of the main part of a powder compacting press machine, Fig. 2 is a vertical cross-sectional view of an automatic dimension measuring device, and Fig. 3 is a vertical cross-sectional view of an automatic dimension measuring device. The block diagram of the circuit, FIG. 4, is an explanatory diagram for measuring dimensions. Explanation of symbols: 1...Main shaft, 2...Upper ram, 3...Frame, 3a...Measurement table, 4...Conrod, 6 ...Pressure sensor for upper punch, 7...Top punch, 8...
...Die table, 9...Die, 10...Outer punch, 11...Inner punch, 12.
... Core rod, 13 ... Punch plate, 14, 14X ... Pressure sensor for outer punch,
15... Busher, 16, 16X...
・Pressure sensor for inner punch, 17...Base plate, 18...Slide block, 19
... Yoke plate, 20 ... Guide rod, 21, 21X ... Core pressure sensor, 22 ...
...Lower ram, 23, 24...Hydraulic cylinder, 25.
...Upper slide plate, 26...Lower slide plate,
27, 28... Guide pot, 29a, 29b, 2
9c, 30a, 30b, 30c... Magnetic sensor, 31... Guide groove, Sl, S2... Rotary cam switch.

Claims (1)

[Claims] 1. A pressure sensor is attached to each part of the powder molding press, such as the die, each punch, etc., and the pressure received by the pressure sensor is automatically measured through the molded product during pressure molding, and the received pressure signal is used in the press cycle. Each part is sequentially detected and compared with the received pressure signal of a preset standard. Then, after knocking out each pressure-formed product, the thickness of each part is automatically measured using a dimension measurement sensor. and sequentially detect each measured dimension signal for each press cycle, and compare it with each dimension signal of a preset standard, so that the received pressure and dimension information correspond to each molded product. The comparison results are taken out sequentially with the timings being matched, and the comparison results are compared with various program data stored in advance in the information analysis processor to perform information analysis and determine whether the molded product is good or bad. A method for monitoring abnormalities in a powder molding press, characterized by generating an output signal that selectively instructs the press to stop or correct, generate an alarm, etc.