JPH0356838B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an automatic slide bottom dead center position correction device in a press, and more specifically, to a device for automatically correcting the bottom dead center position of a slide in a press. The present invention relates to a device that automatically corrects the bottom dead center position of a slide.

In this specification, the vertical relative positional relationship between the slide and the bolster refers to the relative distance between the slide and the bolster at a certain fixed position, such as the bottom dead center.

BACKGROUND ART Conventionally, as a device for correcting the bottom dead center position of a slide in a press, as described in, for example, Japanese Patent Application Laid-open No. 54-65159 and Japanese Patent Application Laid-Open No. 48-30189, When the mold wears out, etc., the press is stopped and the slide is stopped at the top dead center, and the slider is moved up and down relative to the bolster to adjust the vertical relative positional relationship between the slide and the bolster. Are known.

The device described in Japanese Unexamined Patent Publication No. 54-65159 includes a slide adjustment motor that raises and lowers an upper mold holder (slide), a rotary encoder that detects rotational displacement of an output shaft of the slide adjustment motor,
It is provided with a setting dial for setting the lowering degree (distance between the molds) of the upper mold, and controls the rotation of the slide adjustment motor based on the output of the rotary encoder and the output of the setting dial.

The device described in Japanese Patent Application Laid-Open No. 48-30189 includes an adjustment motor for adjusting the stroke position of a ram (slide) into which a tool is inserted, and a deviation between the ram stroke position (actual value and target value). The ram is equipped with a stroke position check mechanism that detects the difference in the ram's stroke position, and uses an adjustment motor to adjust the stroke position of the ram so that the deviation becomes zero.

Problems to be Solved by the Invention In press processing, depending on the type of processing such as coining processing, the positional accuracy of the bottom dead center during processing, that is, the degree of change in the relative distance between the slide and the bolster at the bottom dead center during processing. may become a problem.

The above-mentioned changes in relative distance include variations from stroke to stroke, changes depending on the number of continuous strokes (spm), and changes due to thermal expansion of press components due to frictional heat generated from the drive part of the slide and the guide part of reciprocating motion. There is. Among these, the variation between strokes can be sufficiently reduced by improving the design and manufacturing accuracy of the press, but even with this, the variation due to the number of consecutive strokes and the variation due to heat can be reduced to a small value of, for example, 10 μm or less. is difficult.

By the way, the conventional slide bottom dead center position correction device described above only adjusts the vertical relative positional relationship between the slide and the bolster while the slide is stopped at the top dead center. Since it is not possible to adjust the vertical relative positional relationship between the two, there is a problem in that the position accuracy of the bottom dead center during machining varies due to the reasons described above.

Conventionally, there was no device that could correct the bottom dead center position of the slide during press operation, so in order to improve the positional accuracy of the bottom dead center during machining, a large amount of oil must be circulated within the press to adjust the temperature. It was necessary to prevent the oil from rising, but it required a lot of power to circulate the oil and control the temperature, which was uneconomical.

An object of the present invention is to provide a device that can automatically correct the bottom dead center position of a slide during press operation, and can improve the positional accuracy at the bottom dead center during processing, even without temperature control. .

Means for Solving the Problems The slide bottom dead center position automatic correction device according to the present invention is a slide position adjustment device equipped with an actuator that adjusts the vertical relative positional relationship between the slide and the bolster by a predetermined amount by one operation during press operation. and a detection unit that detects the relative distance between the slide and the bolster at the bottom dead center, and a detection unit that detects the relative distance between the slide and the bolster at the bottom dead center during machining based on the average value of the output of the detection unit during a predetermined number of machining operations at the start of operation. A reference value for the relative distance is determined, and thereafter, the relative distance between the slide and the bolster at the bottom dead center during machining is determined based on the output of the detection unit for each predetermined number of machining operations, and the relative distance between the slide and the bolster at the bottom dead center during machining is determined. When the relative distance of the bolster is out of a predetermined range that includes the above-mentioned reference value, the actuator of the slide position adjustment device is moved once in the direction in which the relative distance of the bolster falls within the above-mentioned range.
The control unit is equipped with a control unit that operates the control unit.

Function During a predetermined number of machining operations at the start of press operation, a reference value for the relative distance between the slide and the bolster at the bottom dead center during machining is determined based on the average value of the output of the detection unit. During press operation thereafter, the relative distance between the slide and the bolster at the bottom dead center during processing is determined based on the output of the detection unit for each predetermined number of processing operations, and the relative distance between the slide and the bolster at the bottom dead center during processing is calculated based on the output of the detection unit. When the distance deviates from a predetermined range including the reference value, the actuator of the slide position adjustment device is actuated once in a direction in which the distance falls within the range, and the vertical relative positional relationship between the slide and the bolster is adjusted.

Therefore, during press operation, the slide bottom dead center position is automatically corrected so as to fall within a predetermined range including the reference value.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The slide bottom dead center position automatic correction device is a slide position adjustment device 2 that adjusts the vertical relative positional relationship between the slide 1 and the bolster (not shown) during press operation.
, a detection unit 3 that directly detects the relative distance between the lower surface of the slide 1 and the upper surface of the bolster at the bottom dead center (hereinafter referred to as the minimum relative distance), and a predetermined range in which the minimum relative distance during machining includes a predetermined reference value. The control unit 4 controls the position adjustment device 2 in the press operation state based on the output of the detection unit 3 during processing so that the press operation starts.

Details of the slide 1 and the slide position adjustment device 2 attached thereto are shown in FIGS. 1-5. This device 2 adjusts the vertical relative positional relationship between the slide 1 and the bolster by adjusting the vertical relative positional relationship between the slide 1 and the connecting rod 5 (or knuckle link). It is composed of

The slide 1 has a box shape and is attached to four vertical guide rods 6 at its four corners so as to be vertically slidable.

A lid 7 is placed on the top of the slide 1 near both left and right ends.
are fitted into each other, and there is a screw 8 at the bottom.
A vertical adjustment threaded rod 9 formed with
It is fitted in the center so that it can slide up and down. A female thread formed on the inner surface of a worm wheel 10 is screwed into the male thread 8 of each threaded rod 9, and each worm wheel 10 is connected to the slide 1 and the lid so that it can rotate but not move in the vertical direction. It is sandwiched between 7. The lower end of each connecting rod 5 is rotatably connected to the upper end of each threaded rod 9 by a horizontal pin 11 extending in the left-right direction.

Two worm shafts 12 extending horizontally in the front-rear direction are rotatably provided inside the slide 1, and a worm 13 fixed to these shafts is engaged with a corresponding worm wheel 10. The two worm shafts 12 are connected by a gear 14 fixed to their front ends and two intermediate gears 15, and rotate in opposite directions in synchronization with each other.

One of the intermediate gears 15 is fixed to the front end of a shaft 17 of an air motor 16 attached to the slide 1. A rear end portion of one of the worm shafts 12 protrudes from the rear surface of the slide 1, and an adjustment gear 18 is fixed to this portion. Further, a bracket 21 integrally formed on one end surface of the first air cylinder 20 is rotatably fitted on the outer periphery of a housing 19 that is fitted from the rear side onto the rear surface of the slide 1 to receive the worm shaft 12. ing. The cylinder 20 is located outside the adjustment gear 18, and has a piston rod 22 that projects toward the gear 18, and a pawl 23 that engages with the gear 18 is integrally formed at the tip of the piston rod 22.

At the upper center of the rear surface of the slide 1, there is a horizontal pin 2 that extends in the front-rear direction at the middle part of the second air cylinder 24.
5, and the tip of the piston rod 26 of this cylinder 24 and the first
A bracket 27 integrally formed on the outside of the cylinder 20 is rotatably connected by a horizontal pin 28 extending in the front-rear direction. first cylinder 2
0 two chambers 29, 30 and the second cylinder 2
The two chambers 31 and 32 of 4 are respectively electromagnetic switching valves 3
3, 34, 35, and 36 to a compressed air source 37.

During press operation, the first valve 33 and the fourth valve 36 are normally open (the air source 37 and the cylinders 20, 2
4 chambers 29 and 32 are in communication), the second valve 3
4 and the third valve 35 are in a closed state (a state in which the air source 37 and the chambers 30, 31 of the cylinders 20, 24 are cut off and the chambers 30, 31 are in communication with the atmosphere), and the first cylinder 20 The pawl 23 has advanced and is seated between the teeth 38 of the adjustment gear 18, and the second
The rod 26 of the cylinder 24 is in the retracted position.
Then, the adjustment gear 18, that is, the worm shaft 12, is prevented from rotating by the pawl 23, and the worm wheel 10 does not rotate. Therefore, the vertical relative positional relationship between the worm wheel 10 and the adjusting screw rod 9, that is, the vertical relative positional relationship between the slide 1 and the connecting rod 5 does not change, and therefore the vertical relative positional relationship between the slide 1 and the bolster remains constant. It is maintained.

When adjusting the relative vertical positional relationship between the slide 1 and the bolster in a direction that increases the relative distance (hereinafter referred to as positive adjustment), the four valves 33, 34, 35, and 36 are controlled as follows. .

That is, first, the first valve 33 is closed and at the same time the second valve 34 is opened. This causes the pawl 23 of the first cylinder 20 to retract and come out from between the teeth 38 of the adjustment gear 18, allowing the first cylinder 20 to rotate freely relative to the adjustment gear 18. Next, the fourth valve 36 is closed and at the same time the third valve 35 is opened. As a result, the rod 26 of the second cylinder 24 advances, and the first cylinder 20 rotates by a certain angle clockwise in FIGS. 3 and 5. At this time, the adjustment gear 18 is stopped. Next, the second valve 34 is closed and at the same time the first valve 33 is opened. As a result, the pawl 23 advances again and fits between the adjacent teeth 38 spaced apart clockwise in FIGS. 3 and 5 from its original position. Finally, the third valve 35 is closed and at the same time the fourth valve 36 is opened. This causes the rod 26 of the second cylinder 24 to retract again, causing the first cylinder 20 to rotate counterclockwise in FIGS. 3 and 5 to its original position. The rotation of this first cylinder 20 is caused by the claw 2
3 to the adjusting gear 18, and the adjusting gear 1
8 is rotated counterclockwise in FIGS. 3 and 5 by one tooth from its original position. Further, the rotation of the adjustment gear 18 is directly transmitted to the fixed worm shaft 12, and furthermore, the rotation of the adjustment gear 18 is transmitted to the fixed worm shaft 12.
5, 15, and 14 to the other worm shaft 12, and the two worms 13 rotate by the same angle in opposite directions. And two worms 1
3 rotates the two worm wheels 10 in the same direction and by the same angle, so that the two worm wheels 10 move upward by the same amount relative to the threaded rod 9.

The amount of movement of the worm wheel 10 relative to the threaded rod 9 when the adjustment device 2 operates once as described above, that is, the amount of adjustment, is, for example, 10 μm.

When adjusting the relative vertical positional relationship between the slide 1 and the bolster in a direction that reduces the relative distance between them (hereinafter referred to as negative adjustment), first close the fourth valve 36 and at the same time close the third valve 35.
open state, then close the first valve 33, simultaneously open the second valve 34, then close the third valve 35, and at the same time open the fourth valve 36. Finally, the second valve 34 is closed and the first valve 33 is opened. As a result, the adjustment gear 18 is rotated by one tooth from its original position in the clockwise direction in FIGS. 3 and 5, contrary to the case of positive correction, and the two worm wheels 10 are Move down by the same amount.

In this slide position adjustment device 2, the first cylinder 20 and the second cylinder 24 adjust the vertical relative positional relationship between the slide 1 and the bolster by a certain amount (in this case, 10 μm) by one operation during press operation.
m) configuring the actuator to be adjusted;

While the adjustment device 2 is operating as described above,
Air motor 16 is in a free state. This air motor 16 is used to greatly change the vertical relative positional relationship between the slide 1 and the connecting rod 5 when the mold is changed, for example, and by rotating the shaft 17 with the air motor 16, the two Two worm wheels 10 move up and down relative to the threaded rod 9.

As shown in FIGS. 6 and 7, the detection unit 3 is a detector that includes two distance detectors (sensors) 39 and two bottom dead center detection circuits 40 connected to these, respectively. 39 detects displacement in a non-contact manner using, for example, an eddy current effect, and is fixed upward by appropriate means to, for example, the left front and right rear parts of the bolster so that the vertical position can be adjusted. ing. On the other hand, two detected blocks 41 are fixed to the slide 1 in correspondence with the two detectors 39 and located directly above them.

The bottom dead center detection circuit 40 outputs a continuous position signal A, a hold signal B, and a count signal C, as shown in FIG.

Continuous position signal A is the normal output of the detector 39, and is the output of the detected block 41 near the bottom dead center a.
In other words, the movement of slide 1 is expressed as is. This signal A is proportional to the displacement of the slide 1 near the bottom dead center a, and for example, 1 mV is
It corresponds to a displacement of 1μm.

The count signal C is turned on only while the continuous position signal A is lower than the threshold level S, that is, while the slide 1 is within a range including the bottom dead center a below a certain position. Therefore,
During normal press operation, the count signal C is turned on once for each stroke.

The hold signal B is a signal in which the value of the continuous position signal A at the bottom dead center a is held from when the count signal C is turned off until the next count signal C is turned off. Therefore, with the hold signal B, it is possible to directly detect the minimum relative distance, especially the change from stroke to stroke.

As shown in FIG. 7, the control section 4 includes a microcomputer 42 that controls the entire correction device, and the continuous position signal A and hold signal B of the two bottom dead center detection circuits 40 of the detection section 3 are sent to a multiplexer. 43, and the output of the multiplexer 43 is input to the amplifier 44, sample hold 45, AD converter 46, photocoupler 47 and interface 48.
The information is input to the computer 42 via the . Further, a count signal C from one bottom dead center detection circuit 40 is input to the computer 42 via a photocoupler 49 and an interface 48 . Then, according to a command from the computer 42, the continuous position signals A and the hold signal B of the two bottom dead center position detection circuits 40 are sequentially converted into digital signals proportional to these signals and input to the computer 42, and the computer 42
The average of the continuous position signals A of the two bottom dead center detection circuits 40 is taken as the detection value of the absolute position of the slider 1, and the average of the hold signals B of the two bottom dead center detection circuits 40 is taken as the detection value of the slider 1. This is the detected value at the bottom dead center position.

A start switch 51, a display 52, a display changeover switch 53 of the display 52, a printer 54, and a reference value correction amount setting dial 55 are connected to the computer 42 of the control section 3, respectively. This dial 55 is used to externally set the amount of correction for the reference value when determining the reference value for the bottom dead center position of the slide 1, which will be the reference for subsequent correction immediately after the start of automatic operation of the press, as will be described later. The positive or negative correction amount can be set, for example, in units of 1 μm. The display 52 has the functions of relative position display, absolute position display, and cumulative correction amount display, and these are switched by a display changeover switch 53. Note that the display contents of the display 52 and the output contents of the printer 54 will be described later.

The four switching valves 33, 34, 3 of the slide position adjustment device 2 are connected to the computer 42 of the control unit 4 via an interface 56 and a photocoupler 57.
5, 36, alarm relay 58, etc. are connected respectively. When performing the above-described positive or negative adjustment of the slide 1, these valves 33, 34, 35, and 36 are controlled by commands from the computer 42.

Next, with reference to the flowchart of FIG. 9, the operating procedure during press working and the operation of the automatic slide bottom dead center position correcting device will be described.

In other words, first, prior to automatic operation of the press,
The slide 1 is stopped at the bottom dead center and the vertical position of the detector 39 is adjusted (step 100). This work is performed with the display 52 switched to absolute position display. In this way, since the detected value of the absolute position of the slide 1 calculated by the computer 42 as described above is continuously displayed on the display 52, it is possible to easily stop the slide 1 at the bottom dead center. Moreover, the relative distance between the detector 39 and the detected block 41 at the bottom dead center can be easily adjusted to an optimal value (for example, 1.5 mm).

After confirming that the desired product is obtained, the automatic operation of the press is started, and the start switch 51 of the correction device is pressed (step
101). As a result, the correction device starts operating, and first, the bottom dead center position reference value of the slide 1 is determined as follows (step 102). That is, the computer 42 of the control unit 4 constantly monitors the count signal C of the bottom dead center detection circuit 40, calculates the number of continuous strokes of the press by counting this, and also calculates the number of continuous strokes of the press. Each time it changes from on to off, the average of the hold signals B of the two bottom dead center detection circuits 40 is taken as the detected value of the bottom dead center position of the slide 1, as described above. Then, for example, the average of the detected values of the bottom dead center position for 100 strokes is calculated, and the value obtained by adding the correction amount set on the reference value correction amount setting dial 55 to this average value is set as the bottom dead center position reference value.

Next, measure the relative position of the bottom dead center position of slide 1 with respect to the bottom dead center position reference value (step
103). The measured value of this relative position is obtained by calculating the average of the detected values of the bottom dead center position for 100 strokes, for example, in the same way as when determining the reference value, and then taking the difference between this average value and the bottom dead center position reference value. It is determined by

Next, it is determined whether the measured value of the relative position is larger than the upper limit (for example, +10 μm) of the no-correction range (step 104), and if it is larger than this, the valve 33 of the slide position adjusting device 2, 34,
35 and 36 to adjust the position of the slide 1 by, for example, 10 μm (step 105).

If the measured value of the relative position is not larger than the upper limit of the no-correction range, it is determined whether this measured value is smaller than the lower limit of the no-correction range (for example -5 μm) (step 106), and if it is smaller than this, Contrary to the above, the position of the slide 1 is adjusted by, for example, 10 μm (step 107).

If the measured value of the relative position is within the range that does not require correction, the process returns to step 103 and the above operations are repeated.
The same applies after the negative adjustment (step 105) or positive adjustment (step 107) is completed. Note that the relative position measurement value is within a certain range (for example +
20 μm to -15 μm), an alarm will be issued.

By adjusting the position of slide 1 based on the relative position measurements every time the press moves, for example, 100 strokes, as described above,
The bottom dead center position of the machine is always maintained within a certain range, resulting in highly accurate products. Note that when the display 52 is switched to display the relative position while the correction device is operating, the measured value of the relative position of the bottom dead center position of the slide 1 mentioned above is displayed, and the display 52 is switched to display the cumulative correction amount. When switched, the cumulative value of the correction amount of the position of slide 1 from the start of operation is displayed. These relative position measurement values and cumulative correction amounts can be output to the printer 54 as needed. Further, the detected value of the absolute position of the slide 1 and the number of continuous strokes of the press can also be outputted to the printer 54 as necessary.

In the above embodiment, the distance detector 39 directly detects the bottom dead center position of the slide 1, that is, the minimum relative distance. , the bottom dead center position of the slide 1 can also be indirectly detected.

It has been found that there is a relationship as shown in FIG. 10 between the number of continuous strokes of the press and the bottom dead center position of the slide. In this figure, the horizontal axis represents the number of continuous strokes (spm), and the vertical axis represents the bottom dead center position of the slide.The number of continuous strokes increases as you move to the right of the horizontal axis, and decreases as you move toward the bottom of the vertical axis. The dead center position has moved downward and the minimum relative distance has become smaller.

In addition, there is a certain relationship between the temperature of the connecting rod and the bottom dead center position of the slide, and if temperature control is not performed, temperature changes will occur as the press operation time passes, and the bottom dead center position will change. changes as shown in FIG. 11, for example. In this diagram,
The horizontal axis represents the press operation time, and the vertical axis represents the bottom dead center position of the slide due to temperature changes in the connecting rod.The press operation time increases toward the right side of the horizontal axis, and toward the bottom of the vertical axis. As the temperature of the connecting rod increases, the bottom dead center position of the slide moves downward, and the minimum relative distance becomes smaller.

Therefore, by detecting the number of continuous strokes and the temperature of the connecting rod, the bottom dead center position of the slide can be indirectly detected.

In this case, the relationship between the number of continuous strokes and the bottom dead center position and the relationship between the temperature and the bottom dead center position as shown in FIG. 10 are memorized for the target press,
The position of the bottom dead center of the slide can be determined based on the detected value of the number of continuous strokes of the press and the detected value of the temperature of the connecting rod from the relationship between these two.
The rest is the same as in the above embodiment.

In addition, based on the detected value of the number of continuous strokes, the correction amount corresponding to the number of continuous strokes is determined from the relationship shown in Figure 10, and the correction amount corresponding to the temperature is calculated from the relationship between the temperature and the bottom dead center position based on the detected value of temperature. It is also possible to calculate the overall necessary correction amount from the correction amount corresponding to the number of consecutive strokes and the correction amount corresponding to the temperature. Note that the temperature is detected using, for example, a thermocouple or a thermistor.

Furthermore, the bottom dead center position of the slide 1 can be indirectly detected by detecting, for example, the number of continuous strokes of the press and the extension of the connecting rod 5.

Generally, when the connecting rod is extended, the bottom dead center position of the slide moves downward, and when the connecting rod is retracted, the bottom dead center position moves upward, and there is a certain relationship between them. Therefore, by detecting the number of continuous strokes and the extension of the connecting rod, the bottom dead center position of the slide can be indirectly detected.

Note that the elongation of the connecting rod is detected using, for example, a strain gauge. The rest is the same as in the case of detecting the number of continuous strokes and the temperature of the connecting rod.

Also, the connecting rod 5 at the bottom dead center
By detecting the compressive force acting on the slide 1, the bottom dead center position of the slide 1 can also be indirectly detected.

Generally, when the bottom dead center position of the slide moves downward, the compressive force acting on the connecting rod at the bottom dead center increases, and when the bottom dead center position moves upward, this compressive force decreases, and between these There is also a certain relationship. Therefore, by detecting the compressive force acting on the connecting rod at the bottom dead center, the bottom dead center position of the slide can be indirectly detected.

Note that the compressive force is detected by, for example, a strain gauge. Since the compressive force acting on the connecting rod generally reaches its maximum at the bottom dead center, it can be detected by finding the maximum value of the compressive force near the bottom dead center. The rest is the same as in the first embodiment.

Effects of the Invention According to the present invention, as described above, the vertical relative positional relationship between the slide and the bolster is adjusted during press operation so that the relative distance between the slide and the bolster at the bottom dead center during processing falls within a predetermined range. It can be corrected to Therefore, the positional accuracy of the bottom dead center during machining, that is, the machining accuracy of the product, can be improved without the need for temperature control as in the past, and the power needed to circulate a large amount of oil can be improved. It is economical because it does not require

In addition, the control unit determines the reference value of the relative distance between the slide and the bolster at the bottom dead center during machining based on the average value of the output of the detection unit during a predetermined number of machining operations at the start of operation. After making an initial adjustment to the vertical relative position of the slide and bolster to obtain the desired results, highly accurate machining can be achieved by simply starting automatic operation, and there is no need for the operator to set reference values. , very easy to operate.

Furthermore, the slide position adjustment device includes an actuator that adjusts the vertical relative positional relationship between the slide and the bolster by a predetermined amount by one operation during press operation, and the control section controls the actuator based on the output of the detection section every predetermined number of machining operations. Control is also very simple because the relative distance between the slide and the bolster at the bottom dead center during machining is determined and the actuator of the position adjustment device is actuated once when this distance is out of the predetermined range.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially cutaway front view showing the slide of the press and the slide position adjustment device attached to it, and FIG.
Fig. 3 is a rear view of Fig. 1;
Figure 4 is an enlarged sectional view taken along the line shown in Figure 3, Figure 5 is an air system diagram of the slide position adjustment device, Figure 6 is a vertical sectional view showing the distance detector portion of the detection unit, and Figure 7 is a vertical sectional view showing the distance detector portion of the detection unit.
The figure is a block diagram of the detection unit and the control unit, Figure 8 is a time chart showing the output signal of the bottom dead center detection circuit of the control unit, and Figure 9 is the operating procedure during press processing and the slide bottom dead center position automatic correction device. Flowchart showing the operation of , Figure 10 is a graph showing an example of the relationship between the number of continuous strokes of the press and the bottom dead center position of the slide, Figure 11 is the relationship between the press operation time and the bottom dead center position of the slide It is a graph showing an example. DESCRIPTION OF SYMBOLS 1... Slide, 2... Slide position adjustment device, 3... Detection part, 4... Control part, 20... First
air cylinder, 24... second air cylinder.

Claims (1)

[Claims] 1. A slide position adjustment device including an actuator that adjusts the vertical relative positional relationship between the slide and the bolster by a predetermined amount by one operation during press operation, and the relative distance between the slide and the bolster at the bottom dead center. A reference value for the relative distance between the slide and the bolster at the bottom dead center during machining is determined based on the detection unit to be detected and the average value of the output of the detection unit during machining a predetermined number of times at the start of operation. The relative distance between the slide and the bolster at the bottom dead center during machining is determined based on the output of the detection unit for each number of machining operations, and the relative distance between the slide and the bolster at the bottom dead center during this machining is determined within a predetermined range that includes the above reference value. Move the actuator of the slide position adjustment device 1 in the direction that it falls within the above range when the
An automatic slide bottom dead center position correction device for a press, which is equipped with a control unit that operates the slide at the bottom of the press.