JP4215297B2 - Method for detecting ram position in punch press - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In a punch press such as a turret punch press, the present invention is based on position data obtained from a position sensor provided to detect the position of a ram or ram head (or punch) (hereinafter simply referred to as a ram) . The present invention relates to a method for detecting an arbitrary return position.
[0002]
[Prior art]
Recently, turret punch presses have come to have a working form in which the operation of the ram is driven and controlled by hydraulic servo control or the like, and the ram is positioned at an arbitrary stroke position, particularly at an arbitrary return position.
[0003]
The return position of the ram is freely controlled mainly in relation to the plate thickness of the workpiece to be punch-pressed.The ram return position should be stopped at a position where the punch blade is slightly away from the workpiece surface. This is because the efficiency of continuous punching is higher than the return to the top dead center (top dead center on the machine).
[0004]
Thus, in order to arbitrarily control the return position of the ram, the standard position of the ram is located at a fixed distance on the cylinder and at the lower end with respect to the upper surface of the die, and the position of the ram Must be capable of accurately measuring and detecting a certain distance from the top surface of the die indicating the respective positions of the ram at the upper and lower ends of the cylinder. Otherwise, when the return position of the ram is changed depending on the thickness of the workpiece, whether or not the ram has returned to the changed position and the output of the position sensor that detects it do not correspond, That is, there is a problem that the detection of the return position of the ram cannot be accurately performed, and it is difficult or impossible to freely control the stroke position of the ram, particularly the return position.
[0005]
In the prior art, in order to realize the ram position specified for each machine with reference to the upper surface of the die, a ram and a ram head (or punch) are assembled, a ram position sensor is attached, and the relationship between the ram position and the sensor output is has a adjust to a predetermined. However, this method has a limit in the position adjustment accuracy of the position sensor itself, and is adjusted based on one of the return point of the ram (upper side) or the bottom dead center of the machining stroke (lower side). There is a problem that the accuracy when viewed from the non-standard side has to be low.
[0006]
[Problems to be solved by the invention]
In view of the current state of the prior art as described above, the present invention relates the relationship between the actual ram position and the ram position detected by the position sensor to the upper and lower ends of the hydraulic cylinder that is the lifting drive source of the ram. It is an object of the present invention to provide a method of moving , obtaining using the position sensor data obtained at that time , and calculating and detecting the return position of the ram.
[0007]
[Means for Solving the Problems]
Configuration of the present invention a method has been made for the purpose of solving the above problems, the ram or the ram head (hereinafter, referred ram) equipped with a function that is positioned at an arbitrary position within the allowed stroke range to the ram when Oite the ram punch press is in the desired position, the city ram from position sensor data of the amount of movement is moved to the prescribed position toward its raised side-end take-out, then the rising side end is moved to a defined position towards lowering side-end retrieves the data of the amount of movement from the position sensor, or processing the extraction data, or until a defined position toward said ram to its drop-side end Move and take the data of the amount of movement from the position sensor, then move it from the descending end to the ascending end and move it to the specified position It retrieves the data from the position sensor, and wherein the determination of the relationship between the data to be fetched from the position sensor and the position of the ram by processing the taken out data.
[0008]
In the present invention, based on the ram position data obtained by the above method, the ram is returned to the original position, which is set as the current position of the ram. If the data obtained by the above operation is stored, the ram can be positioned at the same arbitrary position as described above each time the punch press is restarted. Further, when it is desired to change the return position of the ram in accordance with the change in the workpiece thickness or the like, it is possible to cope with this by adjusting the position data at the arbitrary position.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing a conceptual configuration of a press mechanism in a punch press, FIG. 2 is a functional block diagram of an example of a control system for executing the method of the present invention, and FIG. 3 is a flowchart illustrating an execution procedure of the method of the present invention. .
[0010]
In FIG. 1, 1 is a punch, 2 is a ram, 3 is a hydraulic cylinder that causes the ram 2 to move up and down, and this cylinder 3 is fixed to a fixed frame (not shown). As an example, a body 4a of a linear type potentiometer 4 is attached. The lower end of the rod 4b of the potentiometer 4 is connected to a bracket 2a provided on the ram 2 so that the amount of stroke operation of the ram 2 can be output by an electric quantity (voltage or current). Reference numeral 5 denotes a die arranged on the frame corresponding to the punch 1.
[0011]
In FIG. 1, the ram 2 is assembled at a fixed distance with the upper surface of the die 5 as a reference. As an example, the blade surface 1a of the punch 1 is 48 mm from the upper surface of the die 5 at the rising end of the cylinder 3, and the lowering end. Then, the parameters are set so that the blade surface 1a of the punch 1 penetrates 2 mm from the upper surface of the die 5. In this setting, the ram head may be polished or finely adjusted by the NC parameters. In the following embodiment, the entire stroke of the cylinder 3 will be described as 50 mm based on the above setting.
[0012]
On the other hand, as the position sensor, a linear type encoder that extracts the stroke amount of the ram with a pulse signal may be used. In addition, it is arbitrary whether the output format of the position sensor is of the incremental format or the absolute format. 2 is a control system for the punch mechanism, 6 is a hydraulic device including a hydraulic cylinder 3, 7 is a control device for servo-controlling the operation of the hydraulic device 6 by NC control, etc., and this control system includes the two devices described above. 6 and 7, and the signal from the potentiometer 4 is taken into the control device 7 , and this is processed so that the stroke control of the ram 2 is executed in the hydraulic device 6.
[0013]
In the press machine equipped with the above control system, the method of the present invention is executed as follows as an example. First, when the lower end surface (blade surface) 1a of the punch 1 is at an arbitrary position on the Z-axis, the measured value of the potentiometer 4 in the control device 7 is returned to zero and the hydraulic cylinder 3 is controlled from the control device 7. An ascent command is issued to the hydraulic device 6.
[0014]
The hydraulic cylinder 3 normally rises to the ascending side end defined in the ram 2 by the ascending command. This increase is detected by the potentiometer 4 and stored as an output value of the potentiometer 4 in a memory in the control device 7.
[0015]
The ram 2 that has returned to the ascending end is then supplied with a descending command for the cylinder 3 from the control device 7 to the hydraulic device 6 so that the descending end (here, the lower end surface (blade surface 1a ) of the punch 1 ) From the top surface of the die to -2 mm). This drop is detected by the potentiometer 4 and its output value is stored in a memory in the control device 7.
[0016]
Based on the upper and lower end positions of the ram 2 due to the operation of the cylinder 3 and two output values (voltages) of the potentiometer corresponding to the positions, the return value of the position sensor is calculated in the control device 7. Thus, the coefficients A and B of the calculation formula (for example, ram position = Ax + B) for obtaining the actual position of the ram are obtained, and the ram position is obtained by measuring and inserting x in the above formula. If Motomare ram position, the lower end face of the punch 1, i.e., the initial position of the punch blade 1a, the distance to the rising side end from its position, or is obtained as the distance to the drop-side end from the position of the blade 1a At the same time, the total stroke amount (distance) can be obtained.
[0017]
In the present invention, it is desirable to use a linear sensor such as the potentiometer 4 as the position sensor. This is because, by using the fact that the relationship between the amount of ram movement (input) and the output of the potentiometer 4 changes linearly, an arbitrary position of the ram 2 that is continuously displaced is uniquely determined from the output of the sensor. It is. Of course, even a non-linear position sensor is sufficient if it can obtain an output capable of forming a formula that can calculate the ram position in substitution by obtaining a parameter from the output.
[0018]
In the present invention, the object of direct position control is the blade surface 1a of the punch 1, but in actual control, in order to control this position, control is performed by replacing the data with the ram 2 or appropriate position of the punch 1. is doing. In the case of control based on a part other than the blade surface 1a, the control is based on position data in consideration of the distance between the blade surface 1a and the part. Thus, when the return position of the punch blade 1a in the punching process is changed according to the thickness of the material, the distance from the current return position of the punch blade 1a stored in the control device 7 to the descending end is indicated. It is sufficient to change the value to a value indicating a desired return position.
[0019]
In the above example, since the output of the potentiometer 4 is normally an analog value (voltage), whether the ram 2 has reached the ascending end or the descending end is indicated by a pulse signal. It cannot be detected digitally. In this case, when the amount of change in the output value of the potentiometer 4 is less than a certain value, or when the time longer than the time required for the upper and lower full strokes of the ram has passed, the end is reached. Just look at it. In addition, as another method, there are various means such as monitoring the ram stroke motion in synchronization with the pulse signal, and capturing the moment when the pulse signal is not output and determining the end of the stroke. It is arbitrary whether to adopt this method.
[0020]
On the other hand, if the output format of the position sensor is an incremental encoder, the positioning point of the ram return position can be set by presetting the counter. In the case of an absolute encoder, once the numerical value of the ram position is obtained and taken into the control device 7, then the taken value can be read and the operation can be performed based on that value. When the analog output of the position sensor is used after A / D conversion, measurement is preferably performed after an appropriate warm-up operation in order to obtain a stable digital signal.
[0021]
An example of the execution procedure of the method of the present invention described above will be described based on the flowchart of FIG.
[0022]
When the ram 2 is in any position of the stroke range, increase instruction of the hydraulic cylinder 3 is outputted to the hydraulic unit 6 from the control device 7 (step S1). When the command causes the cylinder 3 to move up the ram 2 and the rising end is detected in step S2, the output value (voltage) of the potentiometer 4 is measured and taken into the control device 7 (step S3). ).
[0023]
When the output value of the potentiometer 4 due to the rising of the cylinder is taken in, the control device 7 outputs a lowering command for the ram 2 to the hydraulic device 6 of the cylinder 3 (step S4). When it is detected in step S5 that the cylinder 3 has reached the lowering end, the output generated in the potentiometer 4 due to this lowering is measured and taken into the control device 7 in step S6. Then, numerical data indicating the position data such as the return position of the ram 2 replaced with the position data of the blade surface 1a of the punch 1 is obtained (step S7 ) .
[0024]
As described above, the position of the ascending side end (return position) and the descending side end defined for the ram that can be positioned at an arbitrary position by the method of the present invention can be defined corresponding to the output of the position sensor, When the position is to be changed, the return position of the ram in the next machining can be immediately changed by adding or subtracting the numerical value to be changed to the return position (upward end) data. In the present invention, the ram position data acquisition is performed by first lowering a ram at an arbitrary position to the descent end and taking the position sensor data, and then raising the ram to the ascending end and taking out the position sensor data. Can also get.
[0025]
【The invention's effect】
Since the present invention is as described above, the relationship between the position sensor and the current return position of the ram can be easily detected, and the return position of the ram can be easily changed.
[0026]
Also, when an analog sensor is used as the position sensor, the output value often changes every time the machining operation is performed. Even in such a case, the present invention is applied by applying the method of the present invention. If the return position is determined, control of the ram return position that is not affected by the ram position data in the previous machining can be realized.
[Brief description of the drawings]
FIG. 1 is a front view showing a conceptual configuration of a press mechanism in a punch press.
FIG. 2 is a functional block diagram of an example of a control system for executing the method of the present invention.
FIG. 3 is a flowchart illustrating the execution procedure of the method of the present invention.
[Explanation of symbols]
1 Punch 2 Ram 3 Hydraulic Cylinder 4 Potentiometer 5 Die 6 Hydraulic Device 7 Control Device

Claims (1)

Ram or the ram head (hereinafter, referred ram) when Oite the punch press equipped with a function that is positioned at an arbitrary position within the stroke range is allowed for the ram ram is in the desired position, the ram It is moved to the prescribed position toward its raised side-end take-out City the data of the amount of movement from the position sensor, then moved from a raised side end to a specified position toward the lowered side-end of the movement amount The data is taken out from the position sensor and the fetched data is processed , or the ram is moved to the specified position toward the descent side end, and the movement amount data is taken out from the position sensor, and then the descent side end. taken out from the position sensor a defined data of the amount of movement is moved to the position was directed to an elevated side end from arithmetically processing the extraction data Detection method of ram position in the punch press, characterized by determining the relationship between the data to be fetched from the position and the position sensor of the prior SL ram Ri by the and.

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