JP2728293B2 - Method of detecting tensile strength during press working - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a method of detecting tensile strength during press working.

(Prior art) Conventionally, a work is sent from a material shelf to a press machine, and after drilling by the press machine, the work is sent to a bending machine for bending, and further, welding is performed by an automatic welding machine. In a series of automated lines, such as in a product storage, there is no way to actually detect the tensile strength of a work, and this has been a bottleneck in obtaining high-precision products in the bending process.

Conventionally, there has been only a method of inputting the data to the NC device of the bending machine assuming the tensile strength of each material of the work before starting the bending process.

(Problems to be Solved by the Invention) In the above-mentioned conventional method, since the tensile strength of each work lot or each work cannot be accurately grasped, the difference in the amount of springback even with the same pressing force and bending stroke is not obtained. And high-precision bending is impossible.

Further, even if the thickness of the work is known, the required bending tonnage could not be calculated because the tensile strength was unknown, and the relationship between the V width and the tensile strength could not be accurately set, and it could only be expected.

Furthermore, the bending of the upper table or the lower table for performing high-precision bending cannot be accurately and automatically corrected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for detecting tensile strength during press working, in which tensile strength can be automatically detected during press working of a work by a press machine.

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides an upper mold and a lower mold by moving a ram up and down according to a ram speed preset by a hydraulic cylinder. During the press working of the work by the cooperation of the above, the pressure sensor detects the pressure data of the ram, and the maximum generated force obtained from the detected pressure data and the die number registered in advance. This is a method of detecting tensile strength during press working in which a die shape is taken into an arithmetic processing device and arithmetic processing is performed by the arithmetic processing device to automatically detect the actual tensile strength of the work.

(Operation) By adopting the method of detecting tensile strength during press working of the present invention, the ram is moved up and down according to a ram speed set in advance by a hydraulic cylinder, and the work is pressed onto the work by the cooperation of the upper die and the lower die. Processing is performed. During the press working of the work, pressure data of the ram is detected by the pressure sensor. When the maximum generated force obtained from this pressure data and the pre-registered mold No. and mold shape are taken into the arithmetic processing unit, the actual tensile strength of the actual work is automatically detected by the arithmetic processing unit. .

Thus, the detected tensile strength is transferred to a bending machine or an automatic welding machine in the next process. In particular, in the NC device of the bending machine, the punching tonnage is calculated, and the relationship between the V width and the plate thickness in bending and the relationship between the V width and the tensile strength can be set.

Also, since the amount of springback after bending is estimated, the data at the time of punching is transferred to the bending machine.
NC device correction is possible.

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

Referring to FIG. 4, the automation line for sheet metal includes a material shelf stocker S, a hydraulic punch press machine P as a press machine, a bending machine B, an automatic welding machine Y and a product storage space G.
Are arranged in a horizontal line, for example. Thus, the work is taken out from the material shelf stocker S and sent to the hydraulic punch press P to perform desired punching. The punched work is sent to a bending machine B, where the desired bending is performed, and the work is sent to an automatic welding machine P in the next step to perform welding on a desired weld. Then, it is sent to the product storage G and stored.

The hydraulic punch press P in the automation line shown in FIG. 4 will be described in more detail. The hydraulic punch press P is formed integrally with the lower frame 1, the column 3 and the upper frame 5 into a portal shape. Have been. Between the lower frame 1 and the upper frame 3, a rotatable lower turret 9 is mounted on a shaft 7 provided on the lower frame 1.
However, a rotatable upper turret 13 is supported on a shaft 11 provided on the upper frame 5 downward.
In addition, the lower turret 9 and the upper turret 13 are rotated in synchronization.

A plurality of punches 15 are provided on the circumference of the upper turret 13,
A die 17 is mounted on the circumference of the lower turret 9 at a position corresponding to the punch 15. The upper frame 5
Is provided with a hydraulic cylinder device 19.

A table 21 is provided on the lower frame 1 so as to be movable in the left-right direction in FIG. 3 (hereinafter referred to as the Y-axis direction). A carriage base 23 is attached to the left end of the table 21. . This College Base 23
In the direction perpendicular to the plane of FIG.
Called the X-axis direction. ) Is provided. A plurality of work clamps 27 capable of clamping the work W are attached to the carriage 25.

With the above-described configuration, by operating the hydraulic cylinder device 19 to move the punch 15 up and down on the work W clamped by the work clamp 27, desired punching is performed in cooperation with the punch 15 and the die 17. At the same time, a plurality of punching operations are performed on the work W by moving the work W in the X-axis and Y-axis directions.

As shown in FIG. 2, the punch 15 is mounted on the upper turret 13 via a punch holder 29, and a groove 13V formed in the upper turret 13 and a punch holder 2 are formed.
The lifter spring 31 is interposed between the punch 15 and the punch 15 and the punch holder 29 and the stripper spring 33 is interposed between the punch 15 and the punch holder 29 while being urged upward. .

The specific configuration of the hydraulic cylinder device 19 is also shown in FIG. That is, in FIG. 2, the hydraulic cylinder lifting device 19 has a structure in which the hydraulic cylinder 39 is supported by a plurality of trunnion pins 37 attached to the main body frame 35.

A piston 41 is mounted on the hydraulic cylinder 39 so as to be vertically movable, and a ram 45 is supported by a wrist pin 43 below the piston 41. Further, a ram guide 47 is mounted inside the main body frame 35 to guide the ram 45 up and down.

At the lower end of the ram 45, a striker 51 is mounted with a plurality of bolts 49.
Is installed. The striker 51 has a ram when the striker 51 moves up and down, that is, when the ram 45 moves up and down.
A position sensor 53 for detecting the position of 45 is provided via an arm member 55.

In the hydraulic cylinder 39, a pressurizing hydraulic chamber 57 is formed at an upper portion with the piston 41 as a boundary, and a returning hydraulic chamber 59 is formed at a lower portion. In the upper part of the hydraulic cylinder 39 is a hydraulic chamber for pressurization.
An oil passage 61 communicating with the oil passage 61 is formed.
Communicates with a manifold 63 provided above the hydraulic cylinder 39. The pressure hydraulic chamber 57 is connected to a pressure sensor 65 for detecting the pressure of the oil fed into the hydraulic pressure chamber 57.

A servo valve 67 is provided above the manifold 63, and a piping 69 is provided at the P port of the servo valve 67.
The other end of the pipe 69 is connected to the hydraulic pump 71. In the middle of the pipe 69, an accumulator 73 and a check valve 75 are provided.

One end of a pipe 77 is connected to the hydraulic pump 71, and the other end of the pipe 77 is connected to a tank 81 via a filter 79. A drive motor 83 is connected to the hydraulic pump 71 in communication. One end of a pipe 85 is connected to the T port of the servo valve 67, and the other end of the pipe 85 is connected to the tank 81.

With the above configuration, by driving the drive motor 83, the hydraulic pump 71 operates, and the oil in the tank 81 is discharged to the pipe 69 via the filter 79, the pipe 77, and the check valve 75. The oil discharged to the pipe 69 is sent from the P port to the servo valve 67 by the action of the accumulator 73, and the valve of the servo valve 67 is controlled based on a machining pattern set in advance by an NC device (not shown) to operate the manifold.
The oil is sent to the pressurizing hydraulic chamber 57 of the hydraulic cylinder 39 through the oil passage 61.

The ram 45 is lowered via the piston 41 by the oil sent into the pressurizing hydraulic chamber 57 of the hydraulic cylinder 39. When the ram 45 descends while being guided by the ram guide 47, the striker
By lowering the punch 51 and pressing the punch 15 down, a desired punching process is performed on the work W by cooperation of the punch 15 and the die 17.

At this time, since the pressure sensor 65 is connected to the pressurizing hydraulic chamber 57 of the hydraulic cylinder 39, the pressure of the oil sent into the pressurizing hydraulic chamber 57 is detected by the pressure sensor 65 each time.
Since the striker 51 is provided with the position sensor 53 via the arm member 55, the striker 51,
The position where 45 has been lowered is detected by the position sensor 53 each time.

Since the movement of the ram 45 is controlled by NC every 1 msec, it is possible to control the ram 45 at the μ level.

FIG. 1 shows an example in which the servo valve 67 is controlled by a command from the NC device to detect the processing pattern of the ram 45, that is, the position and pressure of the ram 45 during one stroke by the position sensor 53 and the pressure sensor 65. ing.

In Figure 1, (in fact the solid line, two-dot chain is NC command) curve C positioning characteristics, the speed V _A of the approach section, the speed V _B of the punch section, (in the case of blanking products) scrap hit抜区between velocity V _C, are defined at the speed V _D of the return section. That is, the ram 45 reaches the position Z ₂ descends T ₁ times at a speed V _A from the position Z ₁ of the top dead center, is decelerated to a speed V _B. Then T ₂
Position Z _3, which is the elapsed time, the tip of the punch 15 is in contact with a position on the upper surface of the workpiece W. Further lowering the ram 45 at a rate V _B, the position Z ₄ of ₃ hours after T is the position at the time of punching a crack is generated in the workpiece W.

After reaching the position Z ₄ is located Z ₅ (bottom dead center) of the later is lowered at a speed V _C than the speed V _B T ₄ hours is the position where the scrap is separated from the workpiece W. Beyond the position Z _5, it being returned the original position at a faster rate V _D than the speed V _C to (Z _1).

Moreover, as the pressure at the time of punching is shown by curve D, pressure is applied from the position Z _3, the maximum occurrence force D ₁ is generated while opening the punch, the pressure at the position of Z ₆ 0 Becomes That is, lowered from the position Z ₄ at a speed V _C, becomes zero pressure after T ₅ hours elapsed, the position Z ₆ corresponds to the lower surface of the workpiece W at the final position which is punched in the workpiece W.

Therefore, as can be seen from FIG. 1, the thickness t of the work W is obtained by the following equation.

t = V _B · (Z ₃ −Z ₄ ) + V _C (Z ₄ −Z ₆ ) (1) Therefore, during the press working in which the work W is being pressed, the descending speed of the ram 45 is changed from the NC device. Since the position data and the pressure data of the ram 45 are detected by the position sensor 53 and the pressure sensor 65 for each workpiece W, the position data and the pressure data It is transferred from the NC unit for the hydraulic punch press P shown in the figure to a host computer HC as an arithmetic processing unit, and is subjected to arithmetic processing by the host computer HC according to the above equation (1), and the thickness t of the work W is calculated. Can be automatically and easily detected and temporarily stored.

Since the plate thickness t temporarily stored in the host computer HC can be transferred to the respective NC units of the bending machine B and the automatic welding machine Y, the accurate plate thickness t can be input in the bending machine B, Variations in bending angle can be minimized. As a result, if there is no variation in the bending angle, man-hours and labor for the next welding step are reduced, and automation is further facilitated.

Further, since the plate thickness t can be transferred to the next process for each work W, there is no longer a case where the plate thickness is controlled for each product lot.

Further, it becomes possible to manage the products one by one, and it is advantageous to correct the shape in the automatic welding machine Y and to manage the bead and the penetration state.

Maximum generation force D ₁ is calculated from the detected pressure data during processing of press working is performed on the workpiece W in Figure 1. In FIG. 4, the hydraulic punch press P
The NC device of the use, previously die No, because the mold shape is pre-registered, the maximum generation force D _1, mold No, die shape is transferred to the host computer HC of the processing unit ,
It is temporarily stored when arithmetic processing is performed based on tensile strength of the workpiece W = maximum generated force / cross-sectional area.

This expanding force is transferred to the respective NC units of the bending machine B and the automatic welding machine Y. In particular, NC in bending machine B
Punching tonnage with equipment = tensile strength of workpiece W x punching circumference x
The thickness (t) is calculated, and the relationship between the V width in bending, the plate thickness t, the V width, and the tensile strength can be set.

Further, since the springback amount after bending can be estimated, the data at the time of punching can be transferred to the bending machine B, and the NC device can be corrected. Further, by correcting the wedge of the lower table in the bending machine B by the NC motor, it is possible to correct the bending of the table.

Further, since the detection of the thickness of the work W and the detection of the tensile strength can be simultaneously transferred to the bending machine B and the automatic welding machine Y, a highly accurate bent product that does not require a previously predicted lot management can be formed and a defective product can be obtained. None.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes.

[Effects of the Invention] As can be understood from the above description of the embodiment, according to the present invention, the ram is moved up and down in accordance with the ram speed set in advance by the hydraulic cylinder, so that the upper die and the lower die are separated. Press work is performed on the work in cooperation. During the press working of the work, pressure data of the ram is detected by the pressure sensor. When the maximum generated force obtained from this pressure data and the pre-registered mold No. and mold shape are loaded into the processing unit, the processing unit automatically detects the actual tensile strength of the actual work. Can be.

Thus, the detected tensile strength is transferred to a bending machine or an automatic welding machine in the next process. In particular, in the NC device of the bending machine, the punching tonnage is calculated, and the relationship between the V width and the plate thickness in bending and the relationship between the V width and the tensile strength can be set.

Also, since the spring bag amount after bending can be estimated, the data at the time of punching is transferred to the bending machine.
NC device correction is possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between position data and pressure data with respect to time in a ram stroke, FIG. 2 is an enlarged detailed view of a portion indicated by an arrow II in FIG. 3, and FIG. 3 is a side view of a hydraulic punch press machine. FIG. 4 is a schematic plan view showing the arrangement of the sheet metal automation line. P: Hydraulic punch press machine, B: Bending machine Y: Automatic welding machine, W: Work 15: Punch, 17: Die 19: Cylinder device, 39: Hydraulic cylinder 45: Ram, 51 …… Striker 53 …… Position sensor, 65 …… Pressure sensor

Claims (1)

(57) [Claims] A ram is moved up and down in accordance with a ram speed set in advance by a hydraulic cylinder to press the work in cooperation with an upper die and a lower die. Along with detecting the pressure data, the maximum generated force obtained from the detected pressure data, and the pre-registered mold No. and the mold shape are taken into the arithmetic processing unit.
A method of detecting tensile strength during press working, wherein the arithmetic processing device performs arithmetic processing to automatically detect the actual tensile strength of the work.