JP4297399B2 - Piercing hole penetration recognition device and recognition method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pierced hole penetration recognition device and a recognition method thereof, a pierce hole penetration recognition device used in a laser processing machine, and a recognition method thereof.
[0002]
[Prior art]
Conventionally, a laser processing machine has a processing head 60 (FIG. 9), and the workpiece W is irradiated with a laser beam L from the processing head 60 to perform a predetermined cutting process on the workpiece W. .
[0003]
However, the process in the case of performing the cutting process from the inside of the workpiece W includes two processes, a piercing process (FIG. 9A) and a cutting process (FIG. 9B).
[0004]
That is, first, as shown in FIG. 9A, with the machining head 60 relatively stopped, a piercing hole P is opened in the vicinity of the start of cutting, and then, as shown in FIG. 9B, By relatively moving the machining head 60 (in the direction of the arrow), the C region on the workpiece W is cut.
[0005]
In the piercing step (FIG. 9A), a time for penetrating the piercing hole P is set, and the time is usually referred to as a plate thickness second (for example, if the plate thickness of the workpiece W is 6 mm). 6 seconds).
[0006]
However, when the workpiece W becomes thicker and the plate thickness seconds become 12, 16, and 19 seconds, the surface state of the workpiece W varies, and therefore the time for penetrating the piercing hole P is long. May be.
[0007]
Therefore, in general, the piercing hole penetration time is set to about 1.5 times the plate thickness of the workpiece W with a margin. For example, if the plate thickness is 6 mm, the piercing hole penetration time is long in advance, such as 6 × 1.5 = 9 seconds. It is supposed to be set.
[0008]
[Problems to be solved by the invention]
[0009]
However, conventionally, even if the pierced hole P has actually penetrated (FIG. 9A) earlier than the preset pierced hole penetration time, it has to wait for the remaining time.
[0010]
Therefore, even if the pierced hole P penetrates, it is not possible to immediately shift to the next cutting step (FIG. 9B), and waiting time is wasted.
[0011]
As a result, the total processing time from the start of processing of the pierced hole P (FIG. 9 (A)) to the end of cutting of the C region (FIG. 9 (B)) becomes longer, leading to a decrease in processing efficiency. .
[0012]
Further, in the piercing process (FIG. 9A), as described above, the machining head 60 remains relatively stopped, so that the laser beam L is actually emitted even after the piercing hole P has penetrated. The workpiece W continues to be irradiated.
[0013]
For this reason, the lower surface of the workpiece W is exposed to the laser light L and becomes dirty, or the laser beam L hits the frame of the machine main body and is damaged.
[0014]
The object of the present invention is to recognize that the pierced hole has actually penetrated in the piercing process and immediately shift to the next cutting process, thereby reducing the total machining time and improving the machining efficiency of the workpiece. And to prevent damage to the machine body.
Previously, the applicant's own patent is related to the so-called “pierce eye” pierce hole penetration recognition such as Patent No. 2837712 or Patent No. 2837748, but there are advantages and disadvantages, and the present invention further ensures that recognition. Provide technology to make
[0015]
[Means for Solving the Problems]
In order to solve the above problems, the present invention, as shown in FIGS.
The tip 3A of the optical fiber 3 is disposed inside the processing head 2 at a position where the visible light S1 emitted when the workpiece W is irradiated with the laser light L can be incident, and is emitted during piercing through the optical fiber 3. The pierced hole characterized by detecting the presence or absence of the inclination of the light receiving level by guiding the visible light S1 and recognizing the penetration of the pierced hole when the inclination disappears for a certain period of time. The technical means of penetration recognition device is taken.
[0016]
According to the configuration of the present invention, the light reception level of the visible light S1 emitted during the piercing process (FIG. 3) is from the time t3 at which the piercing hole P1 begins to open until the time t4 through (FIG. 5). After the penetration (after t4), the inclination of the light receiving level disappears (the part b in FIG. 5), and thus the penetration of the piercing hole is recognized when the state without the inclination continues for a certain time T.
[0017]
This makes it possible to recognize that the pierced hole has actually penetrated in the piercing process, eliminating unnecessary waiting time as before, and reducing the total machining time by immediately moving to the next cutting process. Thus, it is possible to improve the machining efficiency of the workpiece and to prevent the workpiece and the machine body from being damaged.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the accompanying drawings by embodiments.
FIG. 1 is a diagram showing an embodiment of the present invention.
[0019]
The processing head 2 shown in FIG. 1 is attached to a Y-axis carriage belonging to the upper frame 11 (FIG. 8) of the laser processing machine 1 described later.
[0020]
This processing head 2 (FIG. 1) has a nozzle 21 at its tip, and a condensing lens 7 is attached to the base end of the nozzle 21 via fasteners 14 and 15.
[0021]
A bend mirror 10 is attached above the condenser lens 7 via brackets 22 and 23.
[0022]
With this configuration, the laser light L oscillated from the laser oscillator 54 travels straight and is reflected by the bend mirror 10 in the machining head 2, then travels straight toward the condenser lens 7, and passes through the condenser lens 7. The workpiece W is irradiated and condensed at the processing point K.
[0023]
The optical fiber 3 enters the inside from the through hole 20 formed in the processing head 2, and the optical fiber 3 is fixed to the side wall 2 </ b> A by the fiber presser 19, and the tip 3 </ b> A is directed to the processing point K. .
[0024]
As a result, when the workpiece W is irradiated with the laser beam L during piercing (FIG. 7B), the visible light S1 emitted from the processing point K (FIG. 1) where the laser beam L is condensed is: The light enters from the tip 3A of the optical fiber 3, propagates through the optical fiber 3, and enters the controller 4 described later.
[0025]
If the tip 3A of the optical fiber 3 is disposed between the condensing lens 7 and the workpiece W, the nozzle from the bottom of the condensing lens 7 due to spatter or dust generated during processing or from under the condensing lens 7 during processing. The optical fiber 3 is damaged or affected by noise due to the assist gas or the like entering the inside 21.
[0026]
Therefore, according to the present invention, as described above, the tip 3A of the optical fiber 3 is disposed above the condenser lens 7 and on the side of the bend mirror 10, and is damaged by the above-described spatter during processing. It is supposed to work properly without.
[0027]
The optical fiber 3 is connected to the NC device 5 via the controller 4.
[0028]
The details of the controller 4 are shown in FIG. 2 and include a light receiving unit 4A, an amplifier 4B, a level detection unit 4C, an inclination detection determination unit 4D, and an output unit 4E.
[0029]
Among these, the light receiving portion 4A is a photoelectric conversion element that converts the visible light S1 propagating through the optical fiber 3 into an electric signal S2, and is constituted by, for example, a phototransistor.
[0030]
The amplifier 4B amplifies the electrical signal S2 input from the light receiving unit 4A and outputs an amplified electrical signal S3.
[0031]
The level detection unit 4C detects the light reception level (FIG. 3) of the visible light S1 emitted during piercing processing based on the amplified electrical signal S3 input from the amplifier 4B (step 103 in FIG. 6), and the light reception level. The signal S4 is sent to the next-stage inclination detection determination unit 4D.
[0032]
In addition, the inclination detection determination unit 4D detects the presence or absence of the inclination (FIG. 4) based on the light reception level detected by the preceding level detection part 4C (step 104 in FIG. 6). (YES in step 105 in FIG. 6), when the state without the inclination continues for a certain time (YES in step 106 in FIG. 6), the piercing hole penetration signal S5 is sent to the output unit 4E in the next stage.
[0033]
Thereby, the penetration of the pierced hole is recognized, and the piercing process is finished (step 107 in FIG. 6).
[0034]
That is, as shown in FIG. 3, the light receiving level of the visible light S1 emitted during the piercing process is initially nothing when the laser beam L is irradiated from the processing head 2 to the work W at t1. For this reason, it rises rapidly from H1 and is then blocked by steam and the like, and becomes minimum at t2.
[0035]
Then, when the obstruction such as steam is reduced, the light reception level rapidly rises again and becomes H3 at t3. When the piercing hole P1 starts to open, the light reception level decreases as shown in the figure and becomes constant at t4. Pierce hole P1 penetrates.
[0036]
Therefore, if a certain threshold value H2 is set (FIG. 3) and the time point at which the light reception level becomes equal to or less than this threshold value H2 coincides with the time point through which the piercing hole P1 penetrates, the light reception level is below the threshold value H2. Pierce hole penetration can be recognized at the point of time.
[0037]
However, in actuality, as described above, the light receiving level may be equal to or lower than the threshold value H2, for example, at t2 before the piercing hole is penetrated. If only the threshold value H2 is used as a reference, the piercing hole penetration is accurately recognized. Can not.
[0038]
Therefore, by connecting the inclination detection determination unit 4D downstream of the level detection unit 4C (FIG. 2), as shown in FIG. 4, the light reception level data sent from the level detection unit 4C is obtained at predetermined intervals. Extraction is performed to detect the presence or absence of the inclination.
[0039]
For example, the data d1, d2, d3, d4 of the light receiving level of h4, h3, h2, h1 are extracted every τ1, τ2, τ3, τ4, and the extraction time interval τ in that case is assumed to be equal ( τ = τ2-τ1 = τ3-τ2 = τ4-τ3).
[0040]
Accordingly, the inclination of the light reception level in this case is as follows.
[0041]
tanθ1 = (h4-h3) / τ2-τ1 = h 43 / τ ··· ▲ 1 ▼
tanθ2 = (h3-h2) / τ3-τ2 = h 32 / τ ··· ▲ 2 ▼
tanθ3 = (h2-h1) / τ4-τ3 = h 21 / τ ··· ▲ 3 ▼
[0042]
Then, the inclination detection determination unit 4D (FIG. 2) determines the light reception level when the inclination tan θ1 obtained in this way (equation (1) to (3)) is a predetermined value, for example, tan θ _MIN or less. It is assumed that the pierced hole penetration is recognized when the state of no received light level is continued for a certain time, for example, T.
[0043]
The state of the presence or absence of the inclination of the light reception level is shown in FIG. 5, and there is an inclination of the light reception level from t3 when the piercing hole P1 starts to t4 when the piercing hole P1 penetrates (portion a), but t4. Thereafter, the inclination of the received light level disappears (part b), and the state without the inclination continues for a certain time T.
[0044]
By this judgment, it is possible to accurately recognize that the piercing has actually penetrated in the piercing process, and by immediately moving to the next cutting process, the total machining time is shortened and the machining efficiency of the workpiece is improved. And damage to the machine body can be prevented.
[0045]
As shown in FIG. 2, an output unit 4E is connected to the subsequent stage of the inclination detection determination unit 4D that makes such a determination, and when the piercing hole penetration signal S5 is input from the inclination detection determination unit 4D, A piercing processing end signal S6 is sent to the NC device 5 at the next stage (FIG. 1).
[0046]
The NC device 5 (FIG. 1) controls the entire laser beam machine 1 by controlling the laser oscillator 54 and the like.
[0047]
For example, the NC device 5 oscillates the laser light L from the laser oscillator 54 by sending a start signal S7 to the laser oscillator 54 (FIG. 1) during piercing (t3 to t4 in FIG. 3). The workpiece W is irradiated through 2.
[0048]
When the piercing processing end signal S6 is input from the output unit 4E (FIG. 2), the NC device 5 ends the piercing processing (step 107 in FIG. 6). Thereafter, new processing conditions for normal cutting processing are entered.
[0049]
FIG. 8 is a diagram showing a processing machine for processing head Y-axis movement and workpiece X-axis movement as an application example of the present invention. The illustrated laser processing machine 1 straddles the lower frame 12 and the lower frame 12. The upper frame 11 and the processing table 13 are provided.
[0050]
In the upper frame 11, the processing head 2, the optical axis moving mechanism, the laser oscillator 54 (FIG. 1) and the like described above are accommodated.
[0051]
A control box 52 is attached to the side surface of the upper frame 11 (FIG. 8), and the controller 4 (FIG. 1) to which the optical fiber 3 is connected and the NC5 device are built in the control box 52. .
[0052]
An X-axis carriage 17 to which a clamp 16 for gripping the workpiece W is attached is screwed to a ball screw 18 provided in parallel to the longitudinal direction (X-axis direction) of the processing table 13 (FIG. 8).
[0053]
With this configuration, when the ball screw 18 is rotated by the control of the NC device 5 (FIG. 1), the X-axis carriage 17 moves in the X-axis direction, and accordingly, the workpiece W gripped by the clamp 16 is also X-axis. It moves in the direction and is positioned at a predetermined position (step 101 in FIG. 6).
[0054]
When the workpiece W is positioned, a start signal S7 is sent from the NC device 5 (FIG. 1) to the laser oscillator 54 and the workpiece W is irradiated with the laser light L, whereby piercing is started (FIG. 6). Step 102) and thereafter (after Step 103 in FIG. 6), as described above, the light reception level (FIG. 3) of the visible light S1 emitted when the laser light L is condensed at the processing point K (FIG. 8). Various controls such as detection are performed.
[0055]
The operation of the present invention having the above configuration will be described below with reference to FIG.
[0056]
In this case, the product processed by the laser beam machine 1 (FIG. 8) to which the present invention is applied has, for example, the shape shown in FIG. 7A and the product A having circular holes A1 and A2. And
[0057]
In this case, first, in step 101 of FIG. 6, the workpiece W is positioned, piercing is started in step 102, and the light reception level of the visible light S <b> 1 is detected in step 103.
[0058]
That is, the NC device 5 (FIG. 1) controls the ball screw 18 of the laser processing machine 1 (FIG. 8), rotates it, and moves the X-axis carriage 17 in the X-axis direction. The workpiece W also moves in the X-axis direction, and the workpiece W is positioned at a predetermined position.
[0059]
At this time, the machining head 2 is directly above the position where the piercing hole P1 on the workpiece W is to be opened (FIG. 7B).
[0060]
In this state, when the NC device 5 transmits the activation signal S7 to the laser oscillator 54 (FIG. 1), the laser oscillator 54 is activated and the laser beam L is oscillated, and the laser beam L is reflected by the bend mirror 10. The work W is irradiated through the condensing lens 7, and the work point K, in other words, the pierce hole P1 (FIG. 7B) is condensed at a position to be opened.
[0061]
Thereby, piercing is started.
[0062]
On the other hand, the visible light S1 emitted when the laser beam L is irradiated onto the workpiece W (FIG. 1) passes through the condenser lens 7 and enters from the tip 3A of the optical fiber 3, and passes through the optical fiber 3. Propagate and input to the controller 4.
[0063]
In the controller 4, in the light receiving unit 4A (FIG. 2), the visible light S1 is converted into an electric signal S2 and amplified by the next-stage amplifier 4B, and the amplified electric signal S3 is output to output the next-stage level detection unit. Input to 4C.
[0064]
In the level detector 4C, the received light level of the visible light S1 is detected based on the amplified electrical signal S3 (FIG. 3).
[0065]
Next, in step 104 of FIG. 6, the presence or absence of the inclination of the light reception level is detected. In step 105, it is determined whether or not the inclination has disappeared. If there is an inclination (NO), the process returns to step 104. If the same operation is repeated and the inclination disappears (YES), it is determined in step 106 whether or not the state without the inclination has continued for a certain period of time. If not (NO), the process returns to step 104. If the same operation is repeated and continued (YES), the piercing process is terminated in step 107.
[0066]
That is, when the level detection unit 4C detects the light reception level of the visible light S1 (FIG. 2), the level detection unit 4C sends the detection result to the next-stage inclination detection determination unit 4D as the light reception level signal S4.
[0067]
Then, the inclination detection determination unit 4D detects the presence or absence of the inclination of the light reception level (FIG. 3) based on the input light reception level signal S4.
[0068]
For example, as shown in FIG. 4, the slope of the received light level obtained is to be tanθ3 = (h2-h1) / τ4-τ3 = h 21 / τ, if this Tanshita3 is below a predetermined value tan .theta _MIN is We assume that the slope of the received light level is gone.
[0069]
Then, the inclination detection determination unit 4D (FIG. 2) recognizes that the pierced hole has been penetrated when the state in which there is no inclination of the received light level continues for a certain time, for example, T, and the pierced hole penetrates to the output unit 4E in the next stage. Upon receiving the signal S5, the output unit 4E that has received the signal S5 sends the piercing processing end signal S6 to the NC device 5 (FIG. 1).
[0070]
As a result, the piercing process ends, and the NC device 5 sends a new processing condition for the next normal cutting process to the laser oscillator 54.
[0071]
In this way, when the piercing hole P1 penetrates (FIG. 7B), the NC device 5 controls the ball screw 18 (FIG. 8) to position the workpiece W at a predetermined position (FIG. 1). 54 (FIG. 1) is controlled to irradiate the workpiece W with the laser light L, thereby starting cutting processing along the cutting line C1 (FIG. 7B) (step 108 in FIG. 6). .
[0072]
Thereafter, similarly, by performing the operation of FIG. 6 for the piercing hole P2 and cutting line C2, and the piercing hole P3 and cutting line C3 shown in FIG. Is processed (FIG. 7A).
[0073]
【The invention's effect】
As described above, according to the present invention, it is possible to recognize that the piercing hole has actually penetrated in the piercing process, and there is no useless waiting time as in the prior art, and the process immediately proceeds to the next cutting process. As a result, the total machining time was shortened, the machining efficiency of the workpiece was improved, and the technical effect of preventing damage to the workpiece and the machine body was achieved.
[0074]
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is an explanatory diagram of a controller 4 constituting the present invention.
FIG. 3 is a diagram showing a change in the light receiving level of visible light S1 according to the present invention.
4 is a diagram showing a slope of a light reception level in FIG. 3. FIG.
FIG. 5 is a diagram showing a change in inclination of a light receiving level of visible light S1 according to the present invention.
FIG. 6 is a flowchart for explaining the operation of the present invention.
FIG. 7 is a diagram showing a processing state according to the present invention.
FIG. 8 is a diagram illustrating an application example of the present invention.
FIG. 9 is an explanatory diagram of a prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laser processing machine 2 Processing head 3 Optical fiber 4 Controller 5 NC apparatus 7 Condensing lens 10 Bend mirror 11 Upper frame 12 Lower frame 13 Processing table 14, 15 Stopper 16 Clamp 17 X-axis carriage 18 Ball screw 19 Fiber holder 20 Penetration Hole 21 Nozzle 22, 23 Bracket 52 Control box 54 Laser oscillator

Claims (4)

The tip of the optical fiber is placed inside the processing head at a position where visible light emitted when the workpiece is irradiated with laser light, and the visible light emitted during piercing processing is guided through the optical fiber. A pierced hole penetration recognition device that detects the presence or absence of an inclination of the received light level and recognizes the penetration of the pierced hole when the inclination disappears for a predetermined time. The pierced hole penetration recognition device according to claim 1, wherein the tip of the optical fiber is disposed above the condenser lens and on the side of the bend mirror. The pierced hole according to claim 1, wherein the optical fiber is connected to an NC apparatus via a controller, and the controller includes a light receiving unit, an amplifier, a level detection unit, an inclination detection determination unit, and an output unit. Penetration recognition device. The tip of the optical fiber is placed above the condenser lens inside the processing head, and the visible light emitted when the workpiece is irradiated with laser light is captured by the optical fiber, the visible light is guided to the controller, and the light receiving level is determined. A pierced hole penetration recognition method characterized by detecting a change in the received light level over time, detecting the presence or absence of the inclination, and recognizing the penetration of the pierced hole when a state without an inclination continues for a predetermined time.

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