JPH03110021A - Bending method - Google Patents

Abstract

PURPOSE:To bend a sheet material to an accurate angle by deviating one of the lower ends of an upper die from the other end to perform a primary bending, measuring an interval between upper and lower dies and a bent angle of a sheet and lowering the lower end of the upper die in parallel with the lower die down to a value calculated based on the measured value to perform a secondary bending. CONSTITUTION:The sheet 3 is put on the lower die 6 and in a ram stroke in the initial state, the left end of the ram is given by XL0 and the right end thereof is given by XR0. Then, since one end of the upper die 4 is deviated and the left end of the ram stroke is given by XL1 and the right end is given by XR1 to perform the primary bending, intervals between the upper and lower dies 4, 6 differ and the bent angles thetaL1, thetaR1 of the sheet material, too, differ, therefore, the relation of the bent angle after a spring back is generated to the stroke of the upper die 4 is calculated, a stroke calculated as the lower edge of the upper die 4 is set in parallel with the lower die 6 is added to the upper die to perform the secondary bending. Consequently, accurate bent angles thetaL3, thetaR3 can be obtained without needing a trial bending.

Description

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

(Prior art) Conventionally, in order to bend a thin plate material to a predetermined angle using various types of bending machines such as press brakes, the bending process is carried out several times in advance, and then the upper die of the bending machine and the It took a lot of time and effort to readjust the distance between the bottom mold and the other parts. In particular, bending requires skilled workers, which hinders work efficiency.

In recent years, many attempts have been made to simplify the bending process by equipping bending machines with angle control devices. One such attempt is a method for bending a plate-like object disclosed in Japanese Patent Laid-Open No. 61-229421.

In this bending method, the amount of push-in of the punch is measured and the amount of springback after unloading is measured using an angle measuring device.In order to approximate the relationship between the bending angle after springback and the push-in value, Approximation of excessive data using 111 direction lines (2)
The method of approximation was to perform springback 2'-3 times.

(Problems to be Solved by the Invention) However, with the above-described method, 1) a positive push-in value cannot be obtained for each workpiece, and correction is required;

2) Take the time to do a few springbacks.

There are other issues.

The present invention has been made in view of the above circumstances, and its purpose is to accurately measure the amount of push into a workpiece and obtain an accurate bending angle with one unloading without the need for trial bending. The purpose of this paper is to provide a bending method that allows for bending.

(Means for Solving the Problems) In order to achieve the above object, the bending method of the present invention is such that when bending a plate material by lowering the upper die to the lower die of the bending machine, one end of the lower end of the upper die is bent. Perform the first bending process by shifting the position of the lower die in the longitudinal direction from the other end position, measure the distance between the upper die and the lower die at this time, and measure the distance between the upper die and the lower die after unloading. The method is characterized in that the bending angle of the plate material is measured, and the lower edge of the upper die is lowered parallel to the lower die to a value calculated based on these measured values, and a secondary bending process is performed. .

(Function) As mentioned above, since the first bending process is performed with one end of the lower edge of the upper mold being deviated from the other end position, the distance between the upper mold and the lower mold is different, and the bending angle of the plate material is also different. , calculate the relationship between the bending angle after the spring bank with respect to the stroke of the upper die, put the lower edge of the upper die parallel to the lower die, add the calculated stroke to the upper die, and perform a secondary bending process. Therefore, there is no need for trial bending, and production operations can be started immediately for materials of the same quality.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 4. Figure 1 shows a bending machine using the bending method of the present invention; (a) is a front view, (b) is a side view, and
The figure is an operation explanatory diagram, FIG. 3 is a stroke calculation diagram, and FIG. 4 is an operation chart diagram.

In FIG. 1, A is a bending machine, and this bending machine A is installed between two frames B standing upright on the left and right sides, and two frames 8 at the bottom of the frames B. The main body is formed by the bed 5 and a head (not shown) attached to the top of the frame B. A lower mold 6 having a substantially V-groove formed in the longitudinal direction is mounted on the bed 5 of the main body, and cylinders 1 are respectively provided on the frame B at the upper part of the main body. A ram 2 is attached to this cylinder l via a rod so that it can move up and down, an upper mold 4 is attached to the lower end surface of the ram 2, and an upper mold 4 is provided on the lower end surface of the ram 2. The upper mold 4 and the lower mold 6 are brought into close contact with each other by the downward movement of the ram 2. A bending angle detection device 7 is provided at the left and right ends of the upper end of the bed 5, and detects the bending angle when the plate material 3 placed on the lower die 6 is bent into a V-shape by the lowering of the upper die 4. It is designed to measure angles. A press stroke detection device 8 is provided above the bending angle detection device 7 and on the front side of the main body. This press stroke detection device 8 is configured to detect the vertical movement of a protrusion 9 provided at a predetermined position of the ram 2, and to detect the amount of descent of the ram 2, that is, the stroke of the upper mold 4.

In such a configuration, the plate material 3 is placed on the lower die G as shown in Fig. 2(a), and the ram stroke in the initial state is XL''XLO at the left end of the ram and
= X m. Then, as shown in Figure 2 (c), one end of the upper die 4 is deflected and the ram stroke is made at the left end of the ram! X L,, At the right end of the ram, xll-X□. At this time, due to the displacement of the upper die 4, XL≠X□, and the plate material 3 placed on the lower die 6 undergoes the first bending process and is bent. The bending angle at this time is θLI+ at the left end and θ□ at the right end.

In this state, the ram 2 is raised to a range that does not interfere with the springback of the plate material 3, and the load is unloaded as shown in Fig. 2 (C).The ram stroke in this unloaded state is xL at the left end of the ram. ” X Lt+ Measure XII-Xo at the right end of the ram, and the bending angle is θL at the left end!
, measure θ■ at the right end. If the desired final bending angle is θ, then the above-mentioned bending angles θ and θ.

is the press stroke XL which is slightly less than θ
I and X□, which means that it has been bent so that Xtt+X@1.

In other words, when the ram stroke is XL, the angle after springback is θ, and the ram stroke is Xll+
The bending angle after springback when is θ■7.

Previous 81! Shita. When the two relationships in Figure 3 are plotted, with the ram stroke on the horizontal axis and the bending angle after spring bank on the vertical axis, (XLI 0w) (XIl+ θ■), the relationship shown in FIG. These two coordinate points (XLI, θ+, t) (Xi+, 0 *J
By drawing the kl line, it is determined that the ram stroke is X to obtain the final bending angle θ.

Here, the lower edge of the upper die 4 shown in FIG. 2(b) is returned to the parallel state with the lower die 6, and the ram stroke is lowered, the state shown in FIG. 2(d) is reached, and the final bending angle θ1 is θ2−θ1. −〇□ can be obtained. Here, θ. and θ,.

The spring bar 2 exceeds △θ, but 80 will be removed by unloading.

Since FIG. 4 is a chart showing the above-mentioned process, the ram is in the initial state of the upper mold by the Ustadt which represents the frequency of substitute production. Next, at 01・-〇+1, the -E type descends and the second bending process is performed, and Xt"Xt□+X
Measure the stroke of u ””Xll#l, n1=n+
+1 causes the upper mold to enter the unloading process.

After this unloading process, the bending angle θ of the plate material, −〇LoP +
Go to 04・Measure allall and find the first bending angle θ, 6
．． θ□.

From the values of ram stroke XLffil and XR*l, θ7. Calculate the appropriate rams I and loaf Xr that are -〇, -〇, and lower the ram with a stroke that becomes Hereinafter, this process can be returned to the process of 1i: n 1 - n + 1 above.

In addition, in the above explanation, it was described that the lower end ti of one of the upper molds is deviated in a direction closer to the lower mold than the other end, but this means that the stroke of one side of the upper mold is shifted from the other end. Perform the first bending process by increasing the size, and then perform the second bending process based on the fixed value on the side after unloading.
Even if a subsequent bending process is performed, it is equivalent to the present invention.

(Effects of the Invention) As explained in detail above, the bending method of the present invention involves performing the first bending process by deviating one end position of the lower edge of the upper mold from the other end position in the longitudinal direction of the lower mold. At this time, the upper mold 2
:Measure the distance with the lower mold, measure the bending angle of the plate after unloading with the upper mold raised, lower the upper mold to the value calculated from these measurements, and perform the first bending process. Since the plate material is subjected to a secondary bending process, there is no need for trial bending, and there is an advantage that an accurate bending angle can be obtained by unloading once. Further, the bending method of the present invention has the advantage that it can be handled without requiring input of physical properties of different materials, sheet thickness information, etc., and without requiring correction work or sufficient experience in bending.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 shows a bending machine using a bending method, (a) is a front view, (a) is a front view;
I)) is a side view, FIG. 2 is an operation explanatory diagram based on bending, FIG. 3 is a stroke calculation diagram, and FIG. 4 is an operation chart. 4...Upper die 6...Lower die 7...Bending angle detection device 8...Breath l-1: J-reflection detection device 1

Claims (1)

[Claims] When bending a plate material by lowering the upper mold to the lower mold of the bending machine, the first bending process is performed by shifting one end of the lower edge of the upper mold in the longitudinal direction of the lower mold relative to the other end position. At this time, measure the distance between the upper mold and the lower mold, measure the bending angle of the plate material after unloading the upper mold, and bend the lower end of the upper mold to the value calculated based on these measurements. A bending method characterized by lowering the edge parallel to the lower die and performing a second bending process.