JP2001113399A - Press machine diagnosis method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the lowering of a working rate of a press machine by avoiding the stoppage of the press machine in diagnosing and to prevent generation of defect parts in a large quantity by quickly finding the abnormality generated in press forming. SOLUTION: A press machine is diagnosed based on the measured load by measuring the load applied to a machine frame 12h of the press machine. Thus, the diagnosis of parallelism, etc., of the press machine can be conducted in working the press machine in a wide range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for diagnosing an abnormal state of a press machine.

[0002]

2. Description of the Related Art Factors that cause molding defects in press products include abnormalities in the parallelism of press machines. As shown in FIG. 7, the parallelism of the press machine refers to the movable die 18 (the upper die 1).
8) The degree of parallelism of the slide plate 15 that supports the above. If the degree of parallelism is out of the allowable range, an uneven load is applied to the press material, resulting in poor molding of the pressed product. For this reason,
Conventionally, during maintenance of the press machine, the position of the slide plate 15 is adjusted by the dial gauge G to each column 1.
Measurement is performed every 2 hours, and the parallelism is diagnosed based on the measured value.

However, according to the above-described method for diagnosing a press machine, diagnosis cannot be performed unless the press machine is stopped, so that it is impossible to diagnose the parallelism of the press machine during press molding. For this reason, discovery of abnormalities in parallelism or the like that occurred during press molding is delayed, and there is a possibility that many defective products will be generated. In addition, since the diagnosis is performed manually, it takes time to perform the diagnosis, and the press machine must be stopped for a long time for the diagnosis, resulting in a problem that the operating rate of the press machine decreases. To solve such a problem,
A technique for diagnosing abnormalities in a press machine during operation of the press machine is described in JP-A-6-304800. As shown in FIG. 25, the abnormality diagnosis technology of the press machine attaches a strain gauge 72 to each of four plungers 74p (FIG. 25 shows only two for the front view), and uses the strain gauges 72. Slide plate 75
Of the press machine 70 from the measured value
Diagnosis of abnormalities.

[Problems to be solved by the invention]

However, in the above-described abnormality diagnosis technology of the press machine 70, the load applied to the slide plate 75 is measured by the strain gauges 72 attached to the four plungers 74p, and the abnormality of the press machine 70 is diagnosed from the measured value. Therefore, there is a problem that the range of the abnormality diagnosis is limited.

SUMMARY OF THE INVENTION It is an object of the present invention to enable a wide range of diagnosis of a press machine during operation of the press machine.

[0006]

The above object is achieved by a method and an apparatus for diagnosing a press machine according to the first or second aspect of the present invention. According to the present invention, the load applied to the machine frame of the press machine is measured, and the press machine is diagnosed based on the measured load. It can be carried out. For this reason, abnormalities that occurred during press molding can be quickly found, and the mass production of defective products can be prevented. Further, since there is no need to stop the press machine at the time of diagnosis, it is possible to suppress a decrease in the operation rate of the press machine.

[0007] The above-mentioned problem is solved by a method and an apparatus for diagnosing a press machine according to claim 3 or 4. According to the present invention, the load is measured at a plurality of locations in the circumferential direction of the machine frame, and the parallelism of the press machine is determined based on the time difference between the load applied to any one location of the machine frame and the load applied to other locations. Diagnose. For this reason, it is not necessary to manually diagnose the parallelism of the press machine using a dial gauge as in the related art, and the work of parallelism diagnosis is greatly reduced.

[0008] The above-mentioned problem is solved by a method and an apparatus for diagnosing a press machine according to the present invention. According to the present invention, an oil leak of the hydraulic cylinder disposed between the press load applying means and the movable mold is diagnosed based on the load fluctuation state at a predetermined timing during each press forming. For this reason, it is possible to automate the inspection of oil leakage of the hydraulic cylinder, which has been conventionally performed visually, and to quickly find out a malfunction and a molding defect of the press machine due to the inspection.

The above object is solved by a method and an apparatus for diagnosing a press machine according to claim 7 or 8. According to the present invention, to diagnose the overall play of the press machine based on the rise time of the load, conventionally,
It is possible to automate the diagnosis of the overall play, which has been performed visually, and to detect malfunctions and molding defects of the press machine due to the overall play at an early stage.

[0010] The above object is attained by claim 9 or claim 10.
The method and the apparatus for diagnosing a press machine described in (1). According to the present invention, since the counterbalance or the looseness of the tie rod can be diagnosed based on the load at the time of the top dead center, the diagnosis is facilitated, and the malfunction of the press machine due to overbalance or the like can be found at an early stage. .

[0011] The above object is achieved by claim 11 or claim 1
According to a second aspect of the present invention, there is provided a method and apparatus for diagnosing a press machine. According to the present invention, it is possible to determine the friction load of the sliding portion from the difference between the load applied to the machine frame of the press machine and the wrinkle pressing load obtained from the state quantity in the wrinkle pressing device. Becomes possible.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG.
A diagnosis apparatus and a diagnosis method for a press machine according to the first embodiment of the present invention will be described with reference to FIGS. The present embodiment relates to a diagnostic device and a diagnostic method for diagnosing the parallelism of a press machine. FIG. 1 is a longitudinal sectional view schematically showing the press machine, FIG. 2 is a block diagram showing the diagnostic device, and FIG. 3 is a drawing showing a strain gauge unit of the diagnostic device.

First, referring to FIG.
Will be described briefly. The press machine 10 is a single action type press machine for drawing a plate material, and has a bed 11 at its lower part. The bed 1
An opening 11h, which is a concave portion for accommodating a cushion pad 22 and the like described later, is formed at the center of the column 1, and column-like columns 12h constituting a machine frame of the press machine 10 are erected at four places around the opening 11h. Have been. On the column 12h, a gantry 14f for a lifting drive, which also forms a machine frame, is mounted. The bed 11, the column 12h, and the gantry 14f for the lifting drive are firmly connected by tie rods 12t which are vertically passed through the respective columns 12h.

The elevating drive unit 14 includes a mold 18, 1 described later.
9 is a device for applying a press load to the gear 9 and receiving a rotational force of a motor (not shown) to perform a rotary motion.
4h, a crankshaft 14k for converting the rotational movement of the gear mechanism 14h into a vertical reciprocating movement,
It has a pin joint 14j and a connecting rod 14b for transmitting the operation of k to the plunger 14p. The connecting rod 1
4b are provided at four locations in the circumferential direction of the press machine 10, and the plunger 1 is attached to the lower end of each connecting rod 14b.
4p are linked.

[0015] The plunger 14p is a lifting drive device 1.
The plunger 14p is connected to the slide plate 15 through a die height adjusting hydraulic cylinder 13 to transmit a press load from the slide plate 4 to the slide plate 15. That is, the lower end of the plunger 14p is connected to the piston 13p of the hydraulic cylinder 13 for adjusting the die height.
The housing 13 h is integrated with the slide plate 15.

The slide plate 15 is an upper mold 1 of a mold.
8 and moves up and down along a gib 12x fixed to the side surface of the column 12h. Further, four air cylinders 16 for balancer are mounted between the slide plate 15 and the frame 14f for the lifting drive. The balancer air cylinder 16 is a cylinder for applying a lifting force to the slide plate 15, and is adjusted so that the lifting force balances the gravity of the slide plate 15 and the upper die 18.

A strain gauge unit 30 is attached to each column 12h of the press machine 10 at a predetermined position so as to detect a press load applied to the column 12h. For example, as shown in FIGS. 3A, 3B, and 3C, the strain gauge unit 30 includes two strain gauge pieces 32 arranged in a vertical direction and two pieces in a horizontal direction.
The wires of the respective strain gauge pieces 32 are directly connected to form a Wheatstone bridge, and the strain gauge pieces 32 are integrally waterproof-molded. Each strain gauge piece 32 constituting the strain gauge unit 30 is distorted together with the column 12h when the column 12h is distorted by receiving a press load, and its resistance value changes. As a result, the output voltage E of the Wheatstone bridge
(The output voltage E of the strain gauge unit 30) changes (see FIG. 3C). Here, the strain gauge unit 30
Is adjusted to correspond to the press load applied to the column 12h.

When a Wheatstone bridge is constituted by four strain gauge pieces 32, one strain gauge piece 32
A bridge BOX, which is required when a Wheatstone bridge is composed of the three standard resistors, becomes unnecessary. The strain gauge piece 32 has a resistance value of 1 kΩ and a bridge voltage of DC 10 V. This results in a commonly used resistance value of 12
It is less susceptible to noise as compared to a strain gage piece using a 0Ω strain gage piece and a bridge voltage of DC2V.

The strain gauge unit 30 is integrally molded with a waterproof mold. Thus, the strain gauge unit 30 can be directly attached to the column 12h, and the labor for attaching the strain gauge to the column 12h or the like is reduced as compared with the related art. After that, strain gauge unit 3
0 is simply referred to as the strain gauge 30.

On the bed 11 of the press machine 10,
As shown in FIG. 1, a bolster 17 is installed at a position facing the slide plate 15, and a lower mold 19 is mounted on the bolster 17. Opening 11h of the bed 11 under the bolster 17
The cushion pad 22 is installed so as to be able to slide up and down along the guide 23. The cushion pad 22 receives an upward moving force by an air cylinder 24, and the supply air pressure of the air cylinder 24 is measured by an air pressure sensor 24p attached to an air tank 24t.

A hydraulic cylinder 25 is installed vertically on the upper surface of the cushion pad 22, and a cushion pin 26 is vertically supported by each hydraulic cylinder 25. The cushion pin 26 is inserted into a through hole 26 k formed in the bolster 17 and the lower mold 19, and the tip (upper end) protrudes around the punch 19 f of the lower mold 19. The wrinkle holding ring 20 is horizontally placed on the cushion pins 26. The hydraulic chambers of the hydraulic cylinder 25 communicate with each other, and the hydraulic pressure in those hydraulic chambers is measured by a hydraulic sensor 25p.

Next, the operation of the press machine 10 will be briefly described. When the plate material is set on the wrinkle holding ring 20, the lifting drive device 14 operates and its movement is transmitted to the slide plate 15 via the plunger 14p or the like. Thereby, the slide plate 15
Descends from the position of the top dead center along the gib 12x on the side of the column 12h, and together with the slide plate 15, the upper die 18
Also descends. Then, when the wrinkle pressing surface 18e abuts on the plate material in the process of lowering the upper die 18, the edge of the plate material is sandwiched and restrained by the wrinkle pressing surface 18e of the upper die 18 and the wrinkle pressing ring 20. You. Here, the edge of the plate material is used as the wrinkle holding surface 18e of the upper die 18 and the wrinkle holding ring 2
The force constrained by 0, that is, the wrinkle holding load F is obtained as follows.

The wrinkle holding load F is a value obtained by subtracting the weight W1 of the wrinkle holding ring 20 and the weight W0 of the cushion pad 22 from the force (Pa × A) by which the air cylinder 24 pushes the cushion pad 22 upward. Become equal. That is, F = Pa × A-W1-W0. Here, Pa is a measured value of the air pressure sensor 24p, and A is a cross-sectional area of the air cylinder 24. In this calculation, the force resulting from the sliding resistance of the cushion pad 22 is ignored.
The number of the cushion pins 26 is n, and the hydraulic cylinder 2
Assuming that the hydraulic pressure of No. 5 (measured value of the hydraulic pressure sensor 25p) is Ps, the wrinkle pressing load F is F = Ps × (n × S). Here, S is the sectional area of the hydraulic cylinder 25.

The edge of the plate material is restrained by the upper die 18 and the wrinkle holding ring 20. When the upper die 18 further descends from this state, it is pressed by the upper die 18 and the wrinkle holding ring 20 and the cushion pin 26 , The hydraulic cylinder 25 and the cushion pad 22 apply the force of the air cylinder 24 (Pa ×
It descends against A). Thus, the central portion of the plate material is drawn by the forming surface 18f of the upper die 18 and the punch 19f of the lower die 19. Then, when the upper die 18 and the slide plate 15 reach the bottom dead center, the drawing is completed. When the drawing is completed, the upper die 18 and the slide plate 15 are raised to the position of the top dead center, and the press product is taken out of the press machine 10. Thus, one cycle of press molding is completed.

In the process of lowering the upper die 18, the impact reaction force generated by the upper die 18 pressing the wrinkle holding ring 20 and the lower die 19 generates a slide plate 15, a plunger 14 p, a lifting drive 14, and the like. To each column 12h, and the column 12h receives a load extending in the vertical direction. Each column 1
When 2h is distorted, the strain of each column 12h acts on the strain gauge 30, and the strain gauge 30
And outputs a voltage E corresponding to the load applied to. That is, based on the output voltage E of the strain gauge 30, the strain gauge 3
The load applied to the column 12h to which 0 is attached can be obtained. Further, the press load PF can be obtained by adding the loads applied to the respective columns 12h. That is, the strain gauge 30 corresponds to a load measuring unit of the present invention.

FIG. 4 shows a general change in press load PF during press molding as a function of time. That is, at time T0, the upper die 18 starts to descend from the position of the top dead center, and when the upper die 18 contacts the plate material on the wrinkle holding ring 20 at time T1, the press load PF increases from this timing. This value is substantially equal to the wrinkle holding load F. Further, when the upper die 18, the plate material, the wrinkle holding ring 20 and the like continue to descend and the plate material comes into contact with the punch 19f of the lower die 19 at time T2, the press load PF suddenly increases from this timing, and the plate material Is drawn by the forming surface 18f of the upper die 18 and the punch 19f of the lower die 19.

When the upper die 18 reaches the position of the bottom dead center (time T3), the press load PF becomes maximum, and the drawing is completed. Upper die 18 from bottom dead center
When the wrinkle holding ring 20 rises, the press load P
F suddenly decreases, and at time T4, the plate material is changed to the punch 19 of the lower mold 19.
When moving away from f, the press load PF becomes substantially equal to the wrinkle holding load F. Further, the upper mold 18 rises and the time T
When the upper die 18 separates from the wrinkle holding ring 20 at 5, the press load PF becomes zero.

Next, a diagnostic device for a press machine according to the present embodiment will be described. The diagnostic device 50 includes a strain gauge 30 and a hydraulic sensor 25p as shown in FIG.
And an air pressure sensor 24p and a measurement box 52. As described above, the strain gauge 30 is connected to the press machine 10.
The load applied to each column 12h of the machine frame is measured in the vertical direction of the column 12h. The hydraulic pressure sensor 25p is connected to the cushion pad 22.
Are installed in the middle of a pipe for communicating the hydraulic cylinders 25 with each other.
Is measured. The air pressure sensor 24p is attached to an air tank 24t communicating with the pressure chamber of the air cylinder 24, and measures the air pressure Pa of the air cylinder 24. The measurement BOX 52 takes in the load signal from the strain gauge 30, the hydraulic signal (Ps) from the hydraulic sensor 25p, and the air pressure signal (Pa) from the air pressure sensor 24p, stores each data, and displays the waveform graph on the display screen 54. Is a device that displays data in real time and performs data analysis.
It is mainly composed of personal computers. That is, the measurement box 52 of the diagnostic device 50 corresponds to the diagnostic means of the present invention.

Next, a method of diagnosing the parallelism of the press machine 10 according to the present embodiment will be described with reference to FIGS. First, the machine number of the press machine 10 for diagnosing the parallelism is set (step 101 in FIG. 5A). Next, the press machine 10 is actually operated to perform press molding, and the molding data at that time is input to the diagnostic device 50 (step 102). That is, as shown in FIG. 5B, during the period from the start to the end of press forming, step 111 is performed.
Steps 113 to 113 are repeatedly executed every 1 ms, and the strain gauges 30 attached to each column 12h are
Is stored as data. After the press forming, each column 12 is formed based on the load data.
h, the load waveform during press forming is displayed (Step 1)
14). Here, the load waveform H for each column 12h changes with a tendency similar to the waveform of the press load PF shown in FIG.

Next, the parallelism of the slide plate 15 is calculated based on the load waveform for each column 12h (FIG. 5).
(A) Step 103). The parallelism of the slide plate 15 is obtained by the following procedure. First, as shown in FIG. 6, a reference column 12h (No. 1 column)
The load waveform H2 of the other column 12h (No. 2 column) is compared with the load waveform H1 of FIG. FIG. 6 schematically shows the load waveforms H1 and H2. If the time delay is T
[Second], when the pressing speed is S [mm / sec], the position of the slide plate 15 in the No. 2 column is higher than the position of the slide plate 15 in the No. 1 column by T × S [mm]. Become. That is, the slide plate 15 has an inclination such that the No. 2 column side becomes higher by T × S [mm] between the No. 1 column and the No. 2 column.

Similarly, for the No. 3 column and the No. 4 column, the respective load waveforms (not shown) are compared with the load waveform H1 of the No. 1 column, and the start timing shift T
Thus, the existence of the inclination between the No. 1 to No. 3 columns of the slide plate 15 and the existence of the inclination between the No. 1 to No. 4 columns are grasped. Then, the slide plate 15
If the inclination is within the allowable range, it is determined that the parallelism is satisfied, and the press forming operation is continued. The pressing speed S [mm / sec] is determined by S = 2R × Sinθ. Here, R is the rotation radius [mm] of the crankshaft 14k, and 2R is the rotation diameter [mm] of the crankshaft 14k, that is, the vertical movement of the slide plate 15. Is the rotation angle of the crankshaft 14k per unit time.

As described above, according to the parallelism diagnostic method for the press machine 10 according to the present embodiment, the parallelism of the slide plate 15 can be constantly diagnosed during press molding.
As in the prior art, each column 12 is controlled by the dial gauge G.
Compared with the method of actually measuring the position of the slide plate 15 for each h (see FIG. 7), the diagnosis of the parallelism is easier. In addition, since the parallelism of the slide plate 15 can always be diagnosed,
Molding defects or the like due to the parallelism falling outside the allowable range can be found at an early stage. For this reason, it is possible to prevent the occurrence of a large number of defective products, and it is not necessary to stop the press machine at the time of diagnosis, and it is possible to suppress a decrease in the operation rate. Even when the slide plate 15 is parallel, the rising timing of the load waveform H may be shifted due to backlash of the gib 12x or the like. Therefore, in order to execute the parallelism diagnosis method according to the present embodiment, it is premised that the play of the give 12x or the like is within the allowable range.

(Second Embodiment) A diagnosis apparatus and a diagnosis method for a press machine according to a second embodiment of the present invention will be described below with reference to FIGS. The present embodiment relates to a method for diagnosing oil leakage at a point portion of a press machine, and the diagnostic device 50 used in the first embodiment is used as a diagnostic device for performing the method. When oil leakage occurs in the hydraulic chamber (connection screw point hydraulic chamber) of the die height adjusting hydraulic cylinder 13 which is a point part of the press machine 10, the pressing force from the plunger 14p is not efficiently transmitted to the slide plate 15, The press load PF decreases. In particular, the rate of reduction of the press load PF is greatest at the bottom dead center where the load is maximum. When the press load PF is reduced, molding failure of the press product occurs. Therefore, the press machine 10 constantly monitors the hydraulic pressure in the connection screw point hydraulic chamber (hereinafter referred to as hydraulic chamber), and when the hydraulic pressure falls below a predetermined value. , The hydraulic oil can be automatically supplied to the hydraulic chamber.

For this reason, when oil leakage occurs, the supply of hydraulic oil to the hydraulic chamber becomes frequent, and the hydraulic pressure in the hydraulic chamber fluctuates up and down in a short cycle. Further, the fluctuation cycle of the hydraulic pressure becomes shorter as the leakage amount of the hydraulic oil increases. Since the press load PF substantially corresponds to the oil pressure in the hydraulic chamber, when the oil pressure changes, as shown in FIG. 8, the press load PF also changes correspondingly. Therefore, every time press molding is performed, an oil leak in the hydraulic chamber can be found by storing a press load PF (bottom dead center load) at the bottom dead center and monitoring a change in the bottom dead center load.

FIG. 9 is a flowchart for executing the method for diagnosing oil leakage at a point portion according to the present embodiment. As shown in step 201, every time press molding is performed, molding data (load data) is input to the measurement box 52 and stored, and the bottom dead center load is plotted. The specific method of inputting the molding data is the same as the method of diagnosing the press machine according to the first embodiment (FIG. 5).
(B)). Next, it is determined whether or not the variation range of the bottom dead center load in each press molding is within a determination range (step 202). If the variation range is out of the determination range (see FIG. 8), it is diagnosed as an oil leak. If an oil leak is diagnosed, the NG lamp is turned on (step 204), and if it is diagnosed as normal, the OK lamp is turned on (step 20).
3).

Here, the allowable range is set between about 5 to 20 tons. In the present embodiment, the bottom dead center load is plotted every time press molding is performed. However, a method in which one bottom dead center load is plotted for five or ten times of press molding may be used. Further, in the present embodiment, an allowable range is set, and when the bottom dead center load deviates from the allowable range, it is diagnosed that an oil leak has occurred. good. For example, when the fluctuation rate is larger than the determination value, or when the fluctuation cycle is shorter than the determination cycle, it is determined that an oil leak has occurred. Further, a press load PF near the bottom dead center may be used instead of the bottom dead center load. The diagnosis may be performed based on the load of any one of the columns 12h, or may be performed based on the loads of all the columns 12h. As described above, in the present embodiment, the oil leak can be diagnosed from the change in the bottom dead center load, so that the oil leak can be easily found as compared with the conventional case where the oil leak is visually monitored. In addition, molding defects due to oil leakage can be found at an early stage.

(Third Embodiment) FIGS. 10 and 1
A diagnostic device and a diagnostic method for a press machine according to a third embodiment of the present invention will be described based on FIG. The present embodiment relates to a method for diagnosing aging of a press machine, and the diagnostic device 50 used in the first embodiment is used as a diagnostic device for performing the method. In the press machine 10, when galling occurs in the gear mechanism 14h, the pin joint 14j, or the like, or when the sliding resistance between the gib 12x and the slide plate 15 is large, an extra amount for moving the slide plate 15 up and down is required. A force is required, and the press load PF increases accordingly. Conversely, if there is play in the gear mechanism 14h, the pin joint 14j, etc., the give 12x and the slide plate 15
When the sliding resistance between the slide plate 15 and the slide plate 15 is small, the slide plate 15 is easily moved up and down, so that the press load PF is relatively small. For this reason, the bottom dead center load during press forming is reduced to 1
By storing about one data per day and monitoring the fluctuation of the bottom dead center load, it is possible to diagnose the aging of the press machine 10 as to whether the press machine 10 is in a tendency toward staking or loose. The aging diagnosis is performed in a state in which no oil leakage has occurred in the connection screw point hydraulic chamber.

FIG. 11 is a flowchart for executing the aging diagnosis of the press machine 10 according to the present embodiment. As shown in step 301, each time press molding is performed, molding data (load data) is input to the measurement box 52 and stored, and the bottom dead center load is plotted at a rate of about one data per day. Next, in step 302, the time-varying state of the bottom dead center load is determined. For example, several tens of bottom dead center loads are extracted, and it is determined whether the difference between the first and last bottom dead center loads is equal to or greater than a positive determination value or equal to or less than a negative determination value. If the bottom dead center load does not fluctuate with time, the OK lamp is turned on and the process is terminated (step 303). If the bottom dead center load fluctuates in the upward direction over time, it is conceivable that galling of the gear mechanism 14h, the pin joint 14j, or the like, or the sliding resistance between the gib 12x and the slide plate 15 may increase. Is turned on to end the processing (step 304).

When the bottom dead center load is fluctuating in the descending direction (see FIG. 10), the play of the gear mechanism 14h, the pin joint 14j, etc., and the sliding resistance between the gib 12x and the slide plate 15 are reduced. (Gap 12x play) is considered, so the NG lamp is turned on and the process is terminated (step 305). As described above, in the present embodiment, it is possible to diagnose the secular change of the press machine from the time-dependent change of the bottom dead center load, so that the diagnosis is performed in comparison with the conventional case where the diagnosis is performed visually. This makes it easier to detect molding defects caused by play or the like at an early stage.

(Fourth Embodiment) Hereinafter, FIGS.
A diagnostic device and a diagnostic method for a press machine according to a fourth embodiment of the present invention will be described with reference to FIG. The present embodiment relates to a method for diagnosing the total play of a press machine, and the diagnostic device 50 used in the first embodiment is used as a diagnostic device for performing the method. In the press machine 10, when the backlash of the gear mechanism 14h such as backlash is large, the transmission of force is delayed, so that the rise of the load waveform H for each column 12h is delayed. Therefore, the overall play of the press machine 10 can be diagnosed by comparing the rise time Ts of the load waveform H with no play in the press machine 10 and the rise time Tm of the load waveform H during actual press molding. Can be.

FIG. 13 is a flowchart for executing the comprehensive play diagnosis method of the press machine 10 according to the present embodiment. Here, before executing the processing shown in the flowchart of FIG. 13, the normal load waveform H (reference waveform) in a state where the press machine 10 has no backlash is stored in a personal computer in the measurement BOX 52. First, as shown in step 401, the molding data (load data) during press molding is input to the measurement box 52, and the load is plotted on the vertical axis and the time is plotted on the horizontal axis. Next, in step 402, the rise time Ts of the reference waveform and the rise time Tm of the plotted load waveform H are compared to determine whether or not the rise time difference (Tm−Ts = Te) is within an allowable range. If the rise time difference Te is within the allowable range, the overall play is determined to be within the allowable range, the OK lamp is turned on, and the process is terminated (step 403). If the rise time difference Te exceeds the allowable range, the NG lamp is turned on and the process is terminated (step 404).

As described above, in the present embodiment, by determining the load waveform H from the signal from the strain gauge 30 attached to the column 12h, the overall play of the press machine can be diagnosed. In addition, the diagnosis becomes easier as compared with the case where the diagnosis is performed by visual inspection at the time of maintenance, and molding defects caused by play or the like can be found earlier. The rising slope Ks of the reference waveform is compared with the rising slope Km of the plotted load waveform H,
It is also possible to diagnose the overall play of the press machine from the rise slope difference (Ks-Km).

(Fifth Embodiment) Hereinafter, FIGS.
A diagnostic device and a diagnostic method for a press machine according to a fifth embodiment of the present invention will be described with reference to FIGS. The present embodiment relates to a method for diagnosing an improper counterbalance of a press machine and a loose tie rod, and uses the diagnostic device 50 used in the first embodiment as a diagnostic device for performing the method. Is done. FIG.
As shown in FIG. 4, four balancer air cylinders 16 are mounted between the slide plate 15 and the mount 14f for the lifting drive, and the lifting force of the balancer air cylinder 16 is reduced by the slide plate. It is adjusted to balance the gravity of the upper die 15 and the upper die 18. However, when the lifting force of the balancer air cylinder 16 is larger than the gravity of the slide plate 15 and the upper die 18, the press load PF (top dead center load) at the top dead center has a negative value.

Since the pedestal 14f for the lifting drive is connected to the column 12h by the tie rod 12t, if the tie rod 12t is loose, the pressing load P
A part of F is absorbed by the loose portion of the tie rod 12t, and distortion in the direction of extension of the column 12h during press forming is reduced. That is, the output voltage E of the strain gauge 30 becomes smaller with respect to the press load PF. Therefore, if the tie rod 12t becomes loose after the load test, the load value at the top dead center where no load is applied (top dead center load) becomes a negative value. Therefore, by monitoring the top dead center load every time the press forming is performed, it is possible to diagnose the failure of the counterbalance of the press machine 10 and the looseness of the tie rod.

FIG. 15 is a flow chart for executing a method for diagnosing a poor counterbalance of the press machine 10 and a loose tie-rod according to the present embodiment. First, as shown in step 501, molding data (load data) during press molding is input to the measurement BOX 52, and the load is plotted on the vertical axis and the time is plotted on the horizontal axis. Next, in step 502, it is determined whether or not the top dead center load is within an allowable range based on the zero point. If the top dead center load is within the allowable range, it is diagnosed that the counter balance is good and the tie rod is not loosened, the OK lamp is turned on, and the process ends (step 503). If the top dead center load is out of the allowable range (see FIG. 14), it is diagnosed that the counterbalance is poor and the tie rod is loose, and the NG lamp is turned on to end the processing (step 504).

Here, if the diagnosis is NG, the air pressure supplied to the balancer air cylinder 16 is first adjusted to adjust the counter balancer. If the top dead center load still falls outside the allowable range even after the counter balancer is adjusted, the tie rod is investigated and adjusted.
As described above, in the present embodiment, by determining the top dead center load using the strain gauge 30 attached to the column 12h, it is possible to diagnose a poor counterbalance of the press machine and looseness of the tie rod. In addition, the diagnosis becomes easier as compared with the case of diagnosing the counterbalance in the load test, and a defect of the counterbalance or the like can be found at an early stage.

(Sixth Embodiment) Hereinafter, a diagnosis machine and a diagnosis method for a press machine according to a sixth embodiment of the present invention will be described with reference to the flowchart of FIG. The present embodiment relates to a method of diagnosing a load abnormality of a press machine which causes a quality defect of a press product, and a diagnostic apparatus used in the first embodiment as a diagnostic apparatus for performing the method. 50 are used. When various parts are formed by the press machine 10, the forming load (bottom dead center load) differs for each die for forming the part. Therefore, by monitoring whether or not the bottom dead center load at the time of press forming is within an allowable range for each of the dies to be used, it is possible to early detect abnormalities in load and poor quality of a pressed product due to the abnormal load.

Next, a diagnostic method for a press machine according to the present embodiment will be described with reference to the flowchart of FIG.
First, in step 601, the machine number of the press machine 10 is set, and the number (model number) of the mold used in the press machine 10 of each machine number is set. Then, an allowable range (upper limit judgment value and lower limit judgment value) of the bottom dead center load applied to the front, rear, left and right columns 12h is set for each model number.

Next, the plate material is actually press-formed using a mold of a predetermined model number. At this time, the molding data (load data) during press molding is input to the measurement box 52, and plotted with the load on the vertical axis and the time on the horizontal axis for each column 12h (step 602). Then, in step 603, it is determined whether or not the bottom dead center load is within the allowable range (between the lower limit determination value and the upper limit determination value) corresponding to the model number for each column 12h. If the bottom dead center load is within the allowable range according to the model number for each column 12h, it is determined that there is no load abnormality and the quality of the pressed product is not defective, and the OK lamp is turned on to terminate the processing. (Step 604). Also, some or all of the columns 12h
If the bottom dead center load is out of the allowable range, it is diagnosed that the load is abnormal and the quality of the pressed product is poor, the NG lamp is turned on, and the process is terminated (step 605). Here, the allowable range is set to about 10% of the rated load.

As described above, since the forming data (load data) during the press forming is plotted for each column 12h, the load distribution on the front, rear, left and right of the press machine 10 can be obtained. For this reason, even if the press load PF, which is the sum of the loads applied to the four columns 12h, is normal, when the strength of the load exists in the front, rear, left and right of the mold due to the inclination of the slide plate 15 or the like, the load is abnormal. Is determined. Therefore, it is possible to easily find defective quality of the pressed product due to the imbalance of the load distribution when the press load PF is normal.

As described above, in this embodiment, the load data during press forming is obtained by the strain gauge 30 attached to the column 12h, and the quality of the pressed product can be diagnosed from the load data. It is possible to automate the diagnosis of the quality of pressed products, which had been performed based on the senses.

(Seventh Embodiment) Hereinafter, FIGS.
A diagnostic device and a diagnostic method for a press machine according to the seventh embodiment of the present invention will be described based on the above. The present embodiment relates to a method for diagnosing a load abnormality of a press machine that causes defective quality of a pressed product, similarly to the sixth embodiment, and a first diagnostic apparatus for performing the method. The diagnostic device 50 used in the embodiment is used. In the sixth embodiment, the load abnormality is determined based on whether or not the bottom dead center load at the time of press forming is within an allowable range. However, in the present embodiment, the load waveform at the time of press forming is compared with a normal load waveform. By doing so, a load abnormality is determined.

First, press forming is performed for each mold, and the load waveform for each column 12h when normal press forming is performed is stored in the memory as a reference waveform (FIG. 17).
(A), Steps 701 to 703 in FIG. Next, press molding is performed using a predetermined mold, and the molding data (load data) during the press molding is plotted for each column 12h, with the load on the vertical axis and the time on the horizontal axis. In this way, the load waveform for each column 12h plotted is compared with the reference waveform in units of time, and whether the load difference between the load waveform and the reference waveform at all timings (all points load difference) is within the allowable range is determined. Determine whether or not. Then, if the all-point load difference is within the allowable range for all the columns 12h, the quality of the pressed product is determined to be good, the OK lamp is turned on, and the process ends (step 713). If any of the load differences is out of the allowable range for any of the columns 12h, it is determined that the quality of the pressed product is poor, and NG is determined.
The lamp is turned on to end the processing (step 71).
4).

As described above, also in the present embodiment, the load data during press forming is obtained by the strain gauge 30 attached to the column 12h, and the quality of the pressed product can be diagnosed based on the load data. It is possible to automate the diagnosis of the quality of pressed products, which had been performed based on the senses.

(Eighth Embodiment) Hereinafter, FIGS.
An explanation will be given of a diagnosis device and a diagnosis method of a press machine according to an eighth embodiment of the present invention based on the above. The present embodiment relates to a method for diagnosing a load abnormality of a press machine that causes defective quality of a pressed product as in the seventh embodiment, and a first diagnostic apparatus for performing the method. The diagnostic device 50 used in the embodiment is used. In the seventh embodiment, the load abnormality is determined by comparing the load waveform at the time of press molding with a normal load waveform (reference waveform). However, in the present embodiment, the energy required for press molding is focused on, and this energy is used. The abnormal load is determined by comparing the energy with the energy when the pressed product is normally formed.

Here, the energy E required for press forming is
(Hereinafter referred to as forming energy E) is, as shown in FIG. 19, a time integral value W1 of a load waveform H at the time of press forming.
Is obtained by dividing the time integral value W2 of the load waveform H0 at the time of idling. The molding energy E is the molding energy e1 to e calculated for each column 12h.
It is obtained from the sum of four. First, press molding is performed on a trial basis for each mold, and molding energy E when molding is normally performed is calculated (step 801 in FIG. 20A).
802, 803), and stores the molding energy E in the memory as the reference energy ES (step 804).

In this way, when the reference energy ES is stored for each mold and the preparation for diagnosis is completed, press molding is performed in a normal operation state. When the press forming is performed, the forming data (load data) during the press forming is plotted for each column 12h with the load on the vertical axis and the time on the horizontal axis, and the time of the load waveform H during the press forming. The molding energy E is calculated from the difference between the integral value W1 and the time integral value W2 of the load waveform H0 at the time of idling (step 81).
1, 812). Next, the molding energy E and the reference energy ES are compared, and if the difference is within an allowable range, the quality of the pressed product is determined to be good, the OK lamp is turned on, and the process is terminated (step 814). If the difference between the molding energy E and the reference energy ES is out of the allowable range, it is diagnosed that the quality of the pressed product is poor, the NG lamp is turned on, and the process is terminated (step 815).

As described above, also in this embodiment, the load data during press forming is obtained by the strain gauge 30 attached to the column 12h, and the quality of the pressed product can be diagnosed from the load data. It is possible to automate the diagnosis of the quality of pressed products, which had been performed based on the senses.

The load during the press forming can be grasped by measuring a load waveform during one cycle from when the upper die 18 starts descending from the top dead center and returns to the top dead center again (one cycle). In order to measure the load waveform of one cycle in the press molding, the timing at which the upper die 18 starts descending from the position of the top dead center (measurement start timing) is grasped, and the upper die 18 is again moved to the top dead center. It is necessary to know the return timing (measurement end timing). At present, the measurement start timing and the measurement end timing are determined based on the angle signal of the crankshaft 14k of the press machine 10.

However, since the angle of the crankshaft 14k is detected by an angle sensor, a space for installing the angle sensor and a space for maintenance and inspection are required. For this reason, the equipment cost is increased and maintenance and inspection are troublesome. Therefore, if the measurement start timing and the measurement end timing can be grasped without using the angle sensor, it is preferable in terms of equipment cost and maintenance. Therefore, an example of a method of measuring a load waveform that can determine the measurement start timing and the measurement end timing from the load waveform without using an angle sensor or the like is shown in FIG.
A description will be given based on (A) and (B).

First, the trigger load Hst as a reference for measurement
Is set in advance. Here, the trigger load Hst is set to a value slightly smaller than the wrinkle holding load F. After the measurement start button is turned on (step 901), press forming is performed, load data is input to the measurement BOX 52, and when the load H exceeds the trigger load Hst (step 90).
2) The data from the timing Ts before the time Tt, that is, the data from the time Tts is stored. Furthermore, time Tts
It is determined whether or not the minimum measurement time Tmin has elapsed since (step 904). When the load H becomes smaller than the trigger load Hst after the minimum measurement time Tmin has elapsed (step 905), a time Tt from the timing Te, that is, Data is stored until time Tte.

Here, the minimum measurement time Tmin is equal to the upper die 18
Is set to be approximately equal to the time required to descend from the position of the top dead center to the position of the bottom dead center. Therefore, the load H becomes the trigger load Hs due to the influence of noise or the like at the time of wrinkle holding.
Even when the value is less than t, the data storage is not interrupted. When the upper die 18 is pressed against wrinkles, the load H does not fall below the trigger load Hst due to noise or the like. in this way,
According to the present embodiment, since the measurement start timing and the measurement end timing can be determined from the load waveform, the angle sensor and the like which have been required conventionally become unnecessary.

When the press load PF is measured by the strain gauge 30 attached to each column 12h, the load of the strain gauge 30 is calibrated so that the press load PF and the output signal of the strain gauge 30 correspond to each other. There is a need. The load calibration is generally performed using a load cell R as shown in FIG.

In order to perform load calibration, the upper die 18 and the lower die 19 are removed from the press machine 10 and a predetermined number (four) of load cells R are installed at predetermined positions on the bolster 17 as a pre-stage. Next, the press machine 10 is driven to lower the slide plate 15 to apply a load to the load cell R. At this time, the load (press load PF) when the slide plate 15 presses the load cell R is directly measured by the load cell R, and the pressing reaction force from the load cell R is measured by the slide plate 15 and the plunger 14.
p and each column 12h via the lifting drive device 14 and the like.
And measured by the strain gauge 30. Here, since the load applied to all the load cells R is equal to the load applied to all the columns 12h, the following relational expression is established.

[Press load PF] = [total load cell load] = [calibration coefficient K] × [output voltage of all strain gauges 30] Therefore, the calibration coefficient K is [total load cell load] ÷
It is represented by [output voltage of all strain gauges 30]. But,
In the above-described load calibration method, the upper die 18 and the lower die 19 must be removed from the press machine 10 before the load calibration, and a predetermined number of load cells R must be installed at predetermined positions on the bolster 17. Therefore, it takes time and effort to calibrate the load. Thus, an example of a load calibration method capable of performing load calibration without using a special device such as the load cell R will be described with reference to FIG.

The graph of FIG. 22 shows the waveform of the press load PF and the waveform of the wrinkle holding load F obtained from the hydraulic pressure Ps. As shown in FIG. 22, after the drawing of the plate material (while the upper die 18 is being raised), the edge of the plate material is restrained by the upper die 18 and the wrinkle holding ring 20, that is, The press load PF becomes equal to the wrinkle holding load F during the time T4 to T5 in the drawing. Actually, slide plate 15 and give 12x
And there is a sliding resistance Rx between the
F is a wrinkle holding load F and a load X due to the sliding resistance Rx.
And the sum of However, since the load X is very small compared to the wrinkle holding load F, it is ignored during the load calibration.

The wrinkle holding load F is, as described above,
If the hydraulic pressure of the hydraulic cylinder 25 (measured value of the hydraulic pressure sensor 25p) is Ps, it is represented by F = Ps × (n × S). Here, n is the number of cushion pins 26, and S is the cross-sectional area of the hydraulic cylinder 25. For this reason, the waveform of the wrinkle pressing load F has the same shape as the waveform of the hydraulic pressure Ps (equalizing hydraulic pressure waveform), and differs only in the size.

As described above, between times T4 and T5,
Since the press load PF is considered to be equal to the wrinkle holding load F, for example, the press load PF at the time T6 is set to P
F6, and if the wrinkle holding load F at time T6 is F6 and the output voltage of the entire strain gauge 30 at this time is E6, [pressing load PF6] = [wrinkling holding load F6] =
It is represented by [calibration coefficient K] × [output voltage E6 of all strain gauges 30]. Therefore, the calibration coefficient K becomes [wrinkle holding load F6] ÷ [output voltage E6 of all strain gauges 30]. The time T6 is, for example, a predetermined time after the time of the top dead center or the bottom dead center. As described above, since the load calibration can be easily performed by using the wrinkle pressing load F during the press forming, the labor of the load calibration is greatly reduced.

The press machine 10 has a slide plate 1
The sliding resistance Rx exists between 5 and the give 12x. By measuring the friction load caused by the sliding resistance R,
It is possible to detect an abnormality or the like of a sliding portion and to obtain an accurate press load. Therefore, a method of obtaining a friction load based on the sliding resistance R of the slide plate 15 will be described with reference to FIG. After the drawing of the plate material, the edge of the plate material is restrained by the upper die 18 and the wrinkle retaining ring 20, that is, during the time T4 to T5 in FIG. It is equal to the load obtained by adding the load X resulting from the sliding resistance to the wrinkle holding load F.

That is, [press load PF] = [wrinkle holding load F] + [load X due to sliding resistance]. Therefore, [load X due to sliding resistance] can be obtained from [press load PF]-[wrinkle holding load F]. As described above, the load X caused by the sliding resistance between the slide plate 15 and the gib 12x, which has conventionally been difficult to measure, can be easily obtained.

In the above embodiment, a single action press machine has been described. However, the present invention can be applied to various press machines such as a double action press machine. Although the case where the press material is drawn is described, the present invention can also be applied to the case where various processes such as punching and bending are performed. In addition, the strain gauge 30 is connected to the column 12h constituting the machine frame of the press machine 10.
However, when the press machine has an integrated machine frame without using a column, strain gauges may be attached to the four corners of the machine frame. Further, the strain gauges 30 are attached to the respective columns 12h, that is, the plurality of locations of the machine frame, but the strain gauges may be attached to one location of the machine frame depending on the contents of the diagnosis.

[0072]

According to the present invention, since the diagnosis of the press machine can be easily performed even during the operation of the press machine, the abnormality occurring during the press molding can be quickly found and the mass production of defective products can be prevented. Further, since it is not necessary to stop the press machine at the time of diagnosis, a decrease in the operation rate can be suppressed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically showing a press machine used in a first embodiment of the present invention.

FIG. 2 is a block diagram of a diagnostic device for a press machine according to the first embodiment of the present invention.

FIG. 3 is a wiring connection diagram (A diagram), a plan view (B diagram), and an electric circuit diagram (C diagram) of a strain gauge unit used in the diagnostic device for a press machine according to the first embodiment of the present invention. It is.

FIG. 4 is a load waveform diagram during press forming of a press machine used in the first embodiment of the present invention.

FIG. 5 is a flowchart (FIG. A) showing a method for diagnosing the press machine according to the first embodiment of the present invention, and a flowchart (FIG. B) showing a method for inputting molding data.

FIG. 6 is a schematic load waveform diagram showing a diagnostic method for a press machine according to the first embodiment of the present invention.

FIG. 7 is a schematic view illustrating a conventional press machine diagnosis method.

FIG. 8 is a graph illustrating a transition of a bottom dead center load used in the press machine diagnostic method according to the second embodiment of the present invention.

FIG. 9 is a flowchart illustrating a diagnostic method for a press machine according to a second embodiment of the present invention.

FIG. 10 is a graph showing a transition of a bottom dead center load used in the press machine diagnostic method according to the third embodiment of the present invention.

FIG. 11 is a flowchart illustrating a method for diagnosing a press machine according to a third embodiment of the present invention.

FIG. 12 is a schematic load waveform diagram illustrating a diagnostic method for a press machine according to a fourth embodiment of the present invention.

FIG. 13 is a flowchart illustrating a diagnostic method for a press machine according to a fourth embodiment of the present invention.

FIG. 14 is a schematic load waveform diagram illustrating a diagnostic method for a press machine according to a fifth embodiment of the present invention.

FIG. 15 is a flowchart illustrating a diagnostic method for a press machine according to a fifth embodiment of the present invention.

FIG. 16 is a flowchart illustrating a diagnostic method for a press machine according to a sixth embodiment of the present invention.

FIG. 17 is a schematic view illustrating a method for diagnosing a press machine according to a seventh embodiment of the present invention.

FIG. 18 is a flowchart (FIG. A) for storing a reference waveform used in the press machine diagnostic method according to the seventh embodiment of the present invention, and the press machine according to the seventh embodiment of the present invention; Flow chart (B) showing a diagnosis method
Figure).

FIG. 19 is a schematic view illustrating a method for diagnosing a press machine according to an eighth embodiment of the present invention.

FIG. 20 is a flowchart (FIG. A) for storing reference energy used in the method for diagnosing a press machine according to the eighth embodiment of the present invention, and the press machine according to the eighth embodiment of the present invention. It is a flowchart (B figure) showing a diagnostic method.

FIG. 21 is a drawing (A) showing a load waveform measured by the load waveform measuring method, and a flowchart (B) showing a load waveform measuring method.

FIG. 22 is a drawing showing a load calibration method.

FIG. 23 is a drawing illustrating a generally used load calibration method.

FIG. 24 is a schematic diagram illustrating a method for obtaining a load caused by sliding resistance of a slide plate.

FIG. 25 is a schematic view showing a conventional press machine abnormality diagnosis method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Press machine 12 Machine frame 12h Column 15 Slide plate 18 Upper die 19 Lower die 20 Wrinkle holding ring 22 Cushion pad 24 Air cylinder 24p Air pressure sensor 25 Hydraulic cylinder 25p Air pressure sensor 26 Cushion pin 30 Strain gauge (Load measuring means) 32 Strain gauge piece 50 Diagnostic device 52 Measurement box (Diagnosis means)

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masayoshi Amano 6 Toyota Town, Toyota City, Aichi Prefecture Inside Kyo Toyo Manufacturing Co., Ltd. (72) Inventor Yoshiaki Tsukamoto 6 Toyota Town, Toyota City, Aichi Prefecture Inside Kyo Toyo Manufacturing Co., Ltd. F term (reference) 4E088 AA01 BA01 4E089 FB01 FC04 FC06

Claims (12)

[Claims] 1. A method for diagnosing a press machine, comprising: measuring a load applied to a machine frame of the press machine; and diagnosing the press machine based on the measured load. 2. A press comprising: a load measuring means for measuring a load applied to a machine frame of a press machine; and a diagnosing means for diagnosing the press machine based on the load measured by the load measuring means. Machine diagnostic equipment. 3. The method for diagnosing a press machine according to claim 1, wherein a load is measured at a plurality of positions in a circumferential direction of the machine frame, and the load is applied to another portion with respect to the load applied to one of the machine frames. A diagnostic method for a press machine, comprising diagnosing the degree of parallelism of the press machine based on a temporal shift of a load. 4. The diagnostic device for a press machine according to claim 2, wherein the diagnosing means performs the pressing based on a time lag between a load applied to any one portion of the machine frame and a load applied to another portion. A diagnostic device for a press machine characterized by diagnosing the parallelism of the machine. 5. The method for diagnosing a press machine according to claim 1, wherein the hydraulic cylinder oil is disposed between the press load applying means and the movable mold based on a load variation state at a predetermined timing during each press forming. A method for diagnosing a press machine, comprising diagnosing a leak. 6. The diagnostic apparatus for a press machine according to claim 2, wherein the diagnostic means is arranged between the press load applying means and the movable mold based on a load variation state at a predetermined timing during each press forming. A diagnostic device for a press machine, which diagnoses an oil leak of a hydraulic cylinder. 7. The method for diagnosing a press machine according to claim 1, wherein the overall play of the press machine is diagnosed based on a rise time of a load. 8. The diagnostic apparatus for a press machine according to claim 2, wherein the diagnostic means diagnoses the overall play of the press machine based on a rise time of the load. 9. The method for diagnosing a press machine according to claim 1, wherein the counterbalance or the looseness of the tie rod is diagnosed based on the load at the top dead center. 10. The diagnostic device for a press machine according to claim 2, wherein the diagnostic means diagnoses the counterbalance or the looseness of the tie rod based on the load at the time of top dead center. apparatus. 11. In a wrinkle holding state after the forming of the plate material is completed, the friction of the sliding portion is determined from the difference between the load applied to the machine frame of the press machine and the wrinkle holding load obtained from the state quantity of the wrinkle holding device. A method for diagnosing a press machine, comprising determining a load and diagnosing the press machine. 12. A load measuring means for determining a load applied to a machine frame of a press machine, a wrinkle holding load measuring means for obtaining a wrinkle holding load from a state amount in a wrinkle holding device, and a wrinkle holding after the forming of the plate material is completed. In the state
A diagnostic device for a press machine, comprising: diagnostic means for determining a friction load of a sliding portion from a difference between a load applied to a machine frame and a wrinkle holding load and diagnosing the press machine.