JPH0371923A - Controlling method for bending mill - Google Patents

Abstract

PURPOSE:To efficiently execute the accurate bending work by working based on the temporary depth position and compensating the temporary depth position based on the difference between the detected pressurizing force and the estimated pressurizing force. CONSTITUTION:About the specific work, the presumptive depth position D0 is made based on the every kind of conditions, the work condition, the die condition, the frame condition, etc. The thickness t1 about the work is estimated by pressurizing to the temporary position being made D0 or to the this side of the above position and detecting the actual pressurizing force F with the correlation between the plate thickness t and the pressurizing force F at the proper position. By finding the final depth position D0'=D0+ D based on the estimated plate thickness t1, the bending work is executed. Therefore, the accurate bending work is executed efficiently.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for controlling a bending machine.

(Prior Art) A bending machine bends a workpiece interposed between these molds at a predetermined angle by relative movement of a punch or a die. Generally, a ram that moves the punch or die relative to the other mold is moved to a preset depth position to obtain a predetermined bending angle. The depth position at this time is determined using various data tables such as working conditions, mold conditions, and machine frame conditions, taking into account so-called springback.

However, with bending processing equipment, it is difficult to determine the exact depth position because various factors such as variations in the thickness of the workpiece are involved in the bending angle, so the depth position is tentatively determined using the data table mentioned above. However, the reality is that fine adjustments to the depth position are made through trial and error each time the type of workpiece is changed or for each lot.

(Problems to be Solved by the Invention) As described above, in the conventional control method of a bending machine, the depth position of the ram is determined using a data table of various conditions, but variations in the thickness of the workpiece Due to such factors, uniform control could not be performed, and fine adjustment through trial and error was required.

Therefore, it took a lot of effort and time to finely adjust the depth position, and it was difficult to perform bending with high precision.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for controlling a bending machine that can efficiently perform folding with high precision based on a depth position preset using a data table or the like. .

[Structure of the Invention] (Means for Solving the Problems) A method for controlling a bending machine of the present invention to solve the above problems is as shown in FIG. In the control method of a bending machine that bends a workpiece interposed between these molds at a predetermined angle by moving the workpiece according to various conditions such as workpiece conditions, mold conditions, and frame conditions, Set the depth position, perform actual pressurization to the set temporary depth position DO or a position before it, detect the actual pressurizing force F from the plate thickness at the position and the correlation of pressurizing force F, and Plate thickness for workpiece 1. is estimated, and the final depth position Do'-Do+ΔD is determined blindly based on the estimated plate thickness.

In addition, in the control method of a bending machine that bends a workpiece interposed between these molds at a predetermined angle by relative movement of a punch or die, various conditions such as workpiece conditions, mold conditions, frame conditions, etc. Temporary depth position D using a data table for carrying out the predetermined bending process at
o, and based on the set temporary depth position, perform actual pressurization to that position or a position slightly before it,
Difference Δ between the pressing force Fl detected at that time and the scheduled pressing force
The depth position Do of the plate is corrected by a predetermined amount ΔD based on F, and the corrected depth position is obtained.

It is characterized in that the bending process is performed at -D and +ΔD.

(Function) In the present invention, the depth value preset by table data or the like is used as a temporary depth value, and actual pressurization is executed to that position or a position slightly before it, and the pressurizing force F and plate thickness t at that time are From the correlation, estimate the actual thickness tl of the workpiece,
A depth position correction value ΔD commensurate with the error is calculated.

In addition, the estimated value of the actual thickness of the workpiece obtained in this way is
Since this refers to various condition deviations including plate thickness errors, in order to comprehensively correct the condition deviations, a comprehensive correction value ΔD is obtained based on the difference ΔF between the planned pressing force and the actual pressing force.

(Example) The present invention will be explained in detail below.

FIG. 2 is a front view of a bending machine implementing the present invention.

In the figure, the bending machine 1 has a fixed lower apron 2.
It has an upper apron (ram) 3 that is driven up and down with respect to this apron 2. A die 4 is placed on the upper part of the lower apron 2, and a punch 5 is attached to the lower part of the upper apron 3.

In order to detect the vertical movement of the upper apron 3, encoders E for detecting the positions of both ends of the upper apron 30 are provided in the frame portion (not shown).

Furthermore, cylinders 6 are provided at both ends of the frame portion (not shown) in order to drive the upper apron 3 up and down. A servo valve 8 is connected to both cylinders 6 for supplying pressure oil from a hydraulic pump 7 to the cylinders 6 . The servo valve is controlled by an NC device.

Furthermore, two pressure sensors P and P2 are provided in the upper chamber of the cylinder 6 to detect pressurizing force. One pressure sensor P1 is for low pressure, the other pressure sensor P
Reference numeral 2 is for high pressure, and repressure sensors p and p2 are used by switching as appropriate depending on the pressure value to be detected.

Note that each apron 2.3 is provided with a strain meter 9 for detecting the strain state of each apron.

FIG. 3 is an explanatory diagram of the depth position.

In the figure, a work W having a plate thickness tl is interposed between a die 4 and a bunch 5, and the bunch 5 is lowered to a predetermined height position and then spring-backed to bend the work W in a predetermined manner. It has become. The vertical axis of the bunch 5 is called the depth (D) axis, and its position is called the depth position. The lower side is the plus (+) direction. The die shown is V
The width shoulder part has an R part, and the punch has an R part at the tip.

Generally, the setting of the final depth position DO is based on work conditions,
It is set using table data such as mold conditions and machine (frame) conditions.

For example, if Dl is a geometrically based D value and δ is a condition variable, Do−D, −δ is calculated.

δ-61+62+63+64 δ1: Mechanical deflection δ2: Material properties δ3 Springback staff δ4: Others FIG. 4 shows a block diagram of a control device for controlling the bending machine.

Although the figure only shows the control part for driving the above-mentioned axes, the NC device including this control device also controls the D-axis as well as attached devices such as hydraulic pumps and workpiece supply service robots. It looks like this.

In the figure, a data input section 10 is used to input processing conditions such as the shape and bending angle of the workpiece and the type of mold.

The Do value setting unit 11 uses the database 12 to set a temporary depth device DO of the bunch 5.

The D-axis control unit 13 moves the bunch 5 closer to the depth position Do in a predetermined speed pattern and in a predetermined sequence based on the set Do value.

The D-shaft moving part 14 outputs a valve drive signal to the servo valve 8 in order to drive the bunch 5.

In this example, furthermore, a correction control section 15 shown separately from the above-mentioned axis control section 13, a pressurizing force detecting section 16 connected to this control section 15, and a pressurizing force detected by this detecting section 16 are input. Plate thickness 1. Calculate the estimated value of Do and correct the provisional Do value.
It has a direct value correction 17.

The operation of the control device having the above configuration is shown in the flowchart of FIG.

In step 501, the plate quality, plate thickness (nominal value), bending angle δ0
When the machining conditions are input, a temporary depth value DO is determined using the database 12 in step 502. Also, in order to set the position slightly before the depth value Do, 0
．． Do-d is set using a small value d such as 2 mm.

The bunch 5 is then lowered according to the control diagram shown in FIG. 6, and is temporarily stopped at the Do-d position in step 503.

At this time, in step 504, the pressurizing force F and the oil temperature are detected.

In step 505, the plate thickness tl of the workpiece W is estimated.

The estimation method is shown in FIGS. 7 to 9.

First, the plate thickness t is calculated as t-1(
, -△t...(1), and △twi□ ・Δ%...(2)
is obtained by fuzzy inference.

Here, fuzzy reasoning is used to estimate the plate thickness setting based on the difference ΔF between the planned pressurization force Fo and the actual pressurization force F, but the pressurization force has quite a lot of ambiguity in its relationship with the oil temperature. This is because there are too many ambiguities to conclude that the value obtained from this is an error in plate thickness.

Fig. 7 is an explanatory diagram showing the fuzzy set of the pressure difference ΔF, Fig. 8 is an explanatory diagram showing the fuzzy set of oil temperature, and Fig. 9 is an explanatory diagram showing the fuzzy set of the pressure difference ΔF. FIG. 3 is an explanatory diagram of the Δ% rule used. B stands for Big, M stands for Middle, and S stands for Sma 11.

The fuzzy rule shown in FIG. 9 is 1f'ΔF isF and T isT thenΔ
%-A (F, T)...(3) It is written in the form.

Δ% in the above equation (2) is determined as a weighted average of all rules using the following equation.

As described above, Δ% is determined by formula (4), estimation error Δt of plate thickness t is determined by formula (2), and estimated value 1 of plate thickness is determined by formula (1).

For example, when pressurizing a workpiece with a nominal plate thickness of 1.6 mm, the actual pressurizing force was 50% compared to the planned pressurizing force Fo.
Assume that the oil temperature is 55°C and the oil temperature is 55°C.

Then, in Figures 7 and 8, the membership values of 10M and S are both 0.5, and Δ% is 0 according to equation (4).
%, and the estimated plate thickness t is 1.60 mm.

The optimum depth position Do' can be set by redrawing the database based on the estimated plate thickness tl.
Alternatively, the plate thickness error Δt multiplied by a coefficient k may be subtracted from the temporary depth position Do, and set as DOSODO−Δt·.

Furthermore, we created a rule for fuzzy control in which the sign of the value of each rule in Fig. 9 is reversed, and as shown in Fig. 10, we directly obtain the additional amount △D in fuzzy control. (Steps 1001-1004), Step 10
05 may be used to drive the D axis.

As described above, in this example, the plate thickness t can be estimated by fuzzy reasoning from the difference between the planned pressurizing force and the actual pressurizing force, and the optimum depth position can be determined based on this plate thickness estimate. .

The present invention is not limited to the above embodiments, but can be implemented in any appropriate manner by making appropriate design changes.

[Effects of the Invention] As described above, the present invention is a method for controlling a bending machine as described in the claims. The bending process can be performed efficiently.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an overview of the present invention, FIG. 2 is a front view showing an example of a bending machine, and FIG. 3 is an explanatory diagram showing a bending mode.
Fig. 4 is a block diagram of a control device according to an embodiment of the present invention, Fig. 5 is a two-chart showing its control method, Fig. 6 is a control diagram used in the above control device, and Fig. 7 is a pressurizing force. FIG. 8 is an explanatory diagram showing a fuzzy set of oil temperature, FIG. 9 is an explanatory diagram of fuzzy rules, and FIG. 10 is a flowchart showing another control example. Do...Preset depth position Do'...Optimum depth position t...Plate thickness (to is the nominal plate thickness, tl is the estimated plate thickness) F.
・・Applying force T・・Oil temperature

Claims (2)

[Claims] (1) In a method of controlling a bending machine that bends a workpiece interposed between these molds at a predetermined angle by relative movement of a punch or die, the workpiece conditions, mold conditions, frame A temporary depth position is set based on various conditions, and actual pressure is applied to the set temporary depth position or a position in front of it. A method for controlling a bending machine, characterized by estimating a plate thickness and calculating a final depth position based on the estimated plate thickness. (2) In the control method of a bending machine that bends a workpiece interposed between these molds at a predetermined angle by relative movement of a punch or die, various conditions such as workpiece conditions, mold conditions, frame conditions, etc. A temporary depth position is set using the data table below for performing the specified bending process, and actual pressure is applied to that position or a position slightly before it based on the set temporary depth position. Bending characterized in that the tentative depth position is corrected by a predetermined amount based on the difference between the pressing force detected at that time and the planned pressing force, and the bending process is performed at the corrected depth position. How to control processing machines.