JP7122951B2 - Processing method by laser beam - Google Patents

Description

The present invention relates to a laser beam processing method for processing a workpiece conveyed at a predetermined speed by irradiating the workpiece with a laser beam.

The present applicant has previously proposed a technique of fusing (joining while cutting) superimposed sheets by irradiating them with a laser beam in a method of manufacturing absorbent articles such as disposable diapers (Patent Reference 1).

A laser beam emitted from a light source (laser oscillator) is scanned by a scanner including an XY galvanomirror system and applied to a workpiece. If such a deviation of the irradiation position occurs, the workpiece cannot be fused accurately, resulting in various problems.

For example, Patent Literature 2 proposes a laser positioning processing method for automatically correcting the amount of deviation in the irradiation position of laser light caused by aging. In this method, a positioning reference mark fixedly arranged corresponding to the processing plane is imaged by an imaging camera, and the control means detects the amount of deviation of the irradiation position of the laser beam from the image signal obtained by this imaging, and irradiates the laser beam onto the scanner. This is a method of performing scanning in which the amount of positional deviation is corrected.

Patent Literature 3 proposes a laser beam irradiation method capable of directly monitoring the amount of laser beam irradiation position deviation during processing of a workpiece (during laser irradiation). In this method, an imaging device captures an image of the state of irradiation of a laser beam onto a workpiece that is conveyed while being supported by a support member, and an image of the irradiation trace of the laser beam irradiation on the workpiece and the image of the support member is used. 1) finds the distance from the reference position to the irradiation mark on the supporting member, determines the amount of displacement of the irradiation position of the laser beam, determines whether there is any displacement, and corrects the amount of displacement.

JP 2015-008943 A JP-A-11-309593 JP 2011-212727 A

However, in the processing method proposed in Patent Document 2, since the workpiece and the positioning reference mark are imaged while the workpiece is fixed or stopped on the machining plane, It is not possible to judge whether or not the laser light is being accurately irradiated to the

Moreover, in order to carry out the methods proposed in Patent Documents 2 and 3, an imaging device such as a CCD camera is required, which complicates the device configuration and increases the cost.

The present invention has been made in view of the above problems, and its object is to provide a processing method using a laser beam that can efficiently detect the amount of deviation of the irradiation position of the laser beam using a sensor with simple equipment. That's what it is.

The present invention is a laser beam processing method for processing a workpiece conveyed by a conveying device at a predetermined speed by irradiating the workpiece with a laser beam emitted from a light source while scanning the workpiece with a scanner. ,
Conveying position information obtained by a sensor that detects the conveying position of the conveying device, scanning position information obtained by a sensor that detects the scanning position of the scanner, and reference position information common to the conveying device and the scanner. Based on this, the transport position of the transport device is calculated, the scanning position of the workpiece in the transport direction of the laser beam on the transport device is calculated, and the laser beam is calculated based on the difference between the transport position and the scanning position. The present invention provides a processing method using a laser beam, which obtains the amount of deviation of the light from the workpiece.

According to the processing method of the present invention, it is possible to efficiently detect the amount of deviation of the irradiation position of the laser beam with simple equipment using a sensor, and it is possible to process (fuse) the workpiece with high accuracy. .

FIG. 1 is a perspective view showing a part of the manufacturing process of an underpants-type disposable diaper. FIG. 2 is a perspective view of a laser bonding apparatus for manufacturing pants-type disposable diapers. FIG. 3 is a system configuration diagram for carrying out a processing method using a laser beam according to the present invention. FIG. 4 is a plan view showing the relationship between the movement of the slit-shaped opening and the irradiation of the laser beam. FIGS. 5(a) to 5(d) are timing charts showing changes over time in the position of the cylindrical roll, changes over time in the scan position of the laser light, dog signals, calculation and judgment cycles in the processing method using laser light according to the present invention. . FIGS. 6A to 6C are diagrams showing examples of temporal changes in the transport position x1 and the scan position x2. FIG. 7 is a flow chart showing the processing procedure of the processing method using laser light according to the present invention.

The present invention will be described below based on its preferred embodiments.
First, a method of manufacturing a pants-type disposable diaper, which is an example of a fused sheet body, by a manufacturing process including a laser beam processing method according to the present invention will be described below with reference to FIGS. 1 and 2. FIG.

FIG. 1 is a perspective view showing part of the manufacturing process of an underpants-type disposable diaper, and FIG. 2 is a perspective view of a laser bonding apparatus for manufacturing the underpants-type disposable diaper. , are continuously manufactured through the manufacturing process described below.

That is, as shown in FIG. 1, between the band-shaped outer layer sheet 3a and the inner layer sheet 3b, which are continuously supplied from each raw roll (not shown), there are provided a waist elastic member 5 for forming waist gathers, A plurality of waist elastic members 6 forming circumferential gathers and leg elastic members 7 forming leg gathers are arranged in a state of being elongated at a predetermined elongation rate. At this time, a hot-melt adhesive is continuously or intermittently applied to the waist elastic member 5 and the waist elastic member 6 by an adhesive coating machine (not shown). The sheet 3a and the inner layer sheet 3b are arranged while forming a predetermined waist circumference pattern by a rocking guide (not shown) that reciprocates in a direction orthogonal to the conveying direction. Before the outer layer sheet 3a and the inner layer sheet 3b are superimposed, a hot-melt adhesive is applied by an adhesive coating machine (not shown) to a predetermined portion of either or both of the surfaces facing each other. coated.

As shown in FIG. 1, between a pair of nip rolls 111, belt-shaped outer layer sheets 3a and inner layer sheets 3b are fed in which the waist portion elastic member 5, the waist portion elastic member 6, and the leg portion elastic members 7 are sandwiched in a stretched state. Pressurize with . A band-shaped exterior body 3 is formed by disposing a plurality of elastic members 5, 6, 7 in a stretched state between the outer layer sheet 3a and the inner layer sheet 3b. After that, using an elastic member pre-cutting means (not shown), each of the plurality of waist elastic members 6 and leg elastic members 7 is pressed to correspond to the positions where the absorbent main body 2 described later is to be arranged. Each is divided into a plurality of pieces so that the contractile function is not expressed.

Next, as shown in FIG. 1, a hot-melt adhesive is applied in advance to the absorbent main body 2 manufactured in a separate process, and the absorbent main body 2 is rotated 90° to form a strip-shaped exterior body 3. The absorbent body 2 is intermittently supplied and fixed onto the inner layer sheet 3b. Note that the adhesive for fixing the absorbent main body 2 may be applied in advance not to the absorbent main body 2 but to the position where the absorbent main body 2 is to be arranged on the inner layer sheet 3b.

After that, as shown in FIG. 1, the leg holes LO are formed inside the annular portion surrounded by the leg elastic members 7 in the belt-like outer body 3 on which the absorbent body 2 is arranged. The step of forming the leg holes LO is performed using a rotary cutter, a laser cutter, or the like. In the present embodiment, the leg holes LO are formed after the absorbent main body 2 is placed on the band-shaped exterior body 3, but the leg holes LO may be formed before the absorbent main body 2 is placed. good.

Next, the strip-shaped exterior body 3 is folded in its width direction. More specifically, as shown in FIG. 1 , both side portions of the strip-shaped exterior body 3 along the conveying direction are folded back so as to cover both longitudinal ends of the absorbent main body 2 , thereby extending the absorbent main body 2 in the longitudinal direction. After both ends are fixed, the exterior body 3 is folded in two in the width direction together with the absorbent body 2 . In this way, a diaper continuous body 1' is obtained as a strip-shaped sheet laminate.

The diaper continuous body 1' manufactured through the above steps is irradiated with a laser beam L by the laser joining device 20 shown in FIG. The underpants-type disposable diaper 1 having a pair of side seal portions 4 is continuously manufactured as a product.

Now, the laser bonding apparatus 20 will be described below with reference to FIG.
The illustrated laser bonding apparatus 20 comprises a hollow cylindrical roll 23 having a cylindrical support member 21 rotationally driven in the direction of the arrow (clockwise), and a scanner 10 arranged inside the cylindrical roll 23. I have it. Here, the scanner 10 irradiates the laser beam L toward the cylindrical support member 21 forming the peripheral surface of the cylindrical roll 23, the details of which will be described later. The cylindrical support member 21 has a first surface 21a as an outer peripheral surface and a second surface 21b as an inner peripheral surface. The scanner 10 irradiates the laser beam L toward the second surface 21 b of the support member 21 .

The support member 21 forms the peripheral surface of the cylindrical roll 23 and is fixed in a sandwiched state between a pair of annular frames (not shown) forming the left and right side edges of the cylindrical roll 23 . The support member 21 is composed of a single annular member having the same length as the circumference of the annular frame (not shown). For the material of the support member 21, for example, metal materials such as iron, aluminum, stainless steel, and copper, or materials with high heat resistance such as ceramics are selected.

The support member 21 has a plurality of (eight in the illustrated example) slit-shaped openings 27 through which the laser beam L emitted from the scanner 10 passes, penetrating in the circumferential direction at equal angular pitches (45° pitch). ing. Here, each opening 27 is formed linearly along the rotation axis direction (the Y-axis direction described later) of the cylindrical roll 23 . The laser light L passes through the opening 27, but is blocked from passing through portions of the support member 21 other than the opening 27. As shown in FIG. The opening 27 is formed, for example, by etching, punching, laser processing, or the like, at a predetermined portion of the support member 21 .

In the laser bonding apparatus 20, a second cylindrical roll 25 is arranged adjacent to the cylindrical roll 23, and the peripheral surface of the second cylindrical roll 25 has the same number of openings 27 as the supporting member 21 (example shown in the figure). 8) pressure heads 26 are arranged. Here, each pressure head 26 is provided for one opening 27 formed in the support member 21 and has a rotation axis on an extension line of the rotation axis of the cylindrical roll 23 . Each pressure head 26 is supported by a support portion 24 and can be brought into contact with and separated from the cylindrical roll 23 .

Each pressure head 26 has a function of pressing the strip-shaped diaper continuous body 1' to be fused and cut by the laser beam L toward the cylindrical roll 23 at a position corresponding to the opening 27 formed in the support member 21. have. Here, by rotating the second cylindrical roll 25 synchronously with the cylindrical roll 23, each pressure head 26 rotates in the same direction as the rotation direction of the support member 21 and at the same speed as the peripheral speed of the support member 21. , so that it can circulate along the peripheral surface of the support member 21 . In this embodiment, each pressure head 26 is attached to the second cylindrical roll 25 which is a separate member from the cylindrical roll 23, but each pressure head 26 is formed integrally with the cylindrical roll 23. Also good. Details of the laser bonding apparatus 20 are described, for example, in Japanese Patent Application Laid-Open No. 2016-112166, which was previously filed by the present applicant.

When the underpants-type disposable diaper 1 as a product is manufactured using the laser bonding apparatus 20 configured as described above, the strip-shaped diaper continuous body 1' is continuously conveyed while one side thereof is , the outer surface of the supporting member 21 of the cylindrical roll 23 is brought into contact with the diaper continuous body 1 ′, and the continuous diaper 1 ′ is pressed against the cylindrical roll 23 by the pressure head 26 . More specifically, when the inner surface of the support member 21 is irradiated with the laser light L emitted from the scanner 10, the laser light L passes through a rectangular slit-shaped opening 27 formed in the support member 21 and Since the continuous body of diapers 1' is irradiated with the radiation, the continuous body of diapers 1' is fused to continuously manufacture the underpants-type disposable diapers 1 as products. That is, when the continuous diaper body 1' is irradiated with the laser light L that has passed through the opening 27 from the support member 21 side, the continuous diaper body 1' is divided, and at the same time, the continuous diaper body 1 generated by the division is divided. The cut edges of the outer layer sheet 3a and the inner layer sheet 3b are fused to form side seal portions 4 on both side edge portions of the underpants-type disposable diaper 1 thus manufactured. As for the configuration of the outermost surface of the continuous diaper 1', it is desirable that the outermost surface of the continuous diaper 1' is made of a non-woven fabric from the viewpoint of good fusion of the side seal portions 4. Further, it is more preferable that the nonwoven fabric is composed of fibers of thermoplastic resin, because the fusion is performed more satisfactorily.

By the way, when forming the side seal portion 4 of the underpants-type disposable diaper 1, which is a product, when the laser beam L is not properly irradiated to the planned irradiation position of the laser beam L in the diaper continuous body 1', that is, the laser If the light L is not properly irradiated along the opening 27 of the support member 21 and the irradiation position is deviated from the predetermined position, the side seal portions 4 of the underpants-type disposable diaper 1 cannot be properly welded. Can not. Such a diaper 1 in which the side seal portions 4 are not properly welded may cause problems such as the side seal portions 4 tearing or tearing during use.

Therefore, conventionally, an imaging device such as a CCD camera is used to pick up an image of the trace of laser light irradiation, and the obtained image is processed to determine whether or not the laser light is being properly irradiated. ing.

The laser beam processing method according to the present embodiment uses a sensor to efficiently detect the amount of deviation of the irradiation position of the laser beam without using an imaging device, and determines whether the laser beam is properly irradiated. or not. An example in which the processing method using laser light according to the present embodiment is applied to manufacture the underpants-type disposable diaper 1 described above will be described below.

First, the system configuration for carrying out the processing method using laser light according to the present embodiment will be described with reference to FIG.

That is, FIG. 3 shows the configuration of a system for carrying out a processing method using laser light. In FIG. 2, reference numeral 20 denotes the laser bonding apparatus shown in FIG. The cylindrical roll 23 of the laser bonding apparatus 20 constitutes a conveying apparatus for conveying the diaper continuous body 1' (see FIGS. 1 and 2), which is a workpiece. An endless drive belt 29 is wound between the cylindrical roll 23 and a small-diameter drive roller 28 . When the drive roller 28 is driven to rotate in the direction of the arrow (clockwise) in FIG. The body 1' is transported in the direction of the arrow X in FIG. FIG. 4 is a plan view showing the relationship between the movement of the opening 27 formed in the support member 21 and the irradiation of the laser beam L. The direction perpendicular to the conveying direction X of the diaper continuous body 1' is shown in FIG. The direction along the longitudinal direction of the opening 27 is defined as the Y direction, and the direction perpendicular to the XY direction is defined as the Z direction. The drive motor 30 shown in FIG. 3 is provided with an encoder 31 for detecting the rotational direction and rotational position of the drive motor 30 .

In the vicinity of each opening 27 (see FIG. 4) of the cylindrical roll 23 (supporting member 21), a dog 32 is attached for giving common reference position information to the cylindrical roll 23 and the scanner 10 as will be described later. there is As shown in FIG. 3, a dog sensor 33 for detecting each dog 32 is arranged on the outer peripheral side of the cylindrical roll 23 . A detection signal (dog signal) detected by the dog sensor 33 is transmitted to a controller 40 as control means.

As shown in FIG. 3 , a transport position sensor 34 is arranged at a position facing the outer peripheral surface of the cylindrical roll 23 . A linear encoder (not shown) is installed on the peripheral surface of the cylindrical roll 23 . The conveying position sensor 34 detects the rotational position of the cylindrical roll 23 (conveying position of the continuous diaper 1' as the workpiece) based on an encoder signal from a linear encoder (not shown). A detection signal (conveyance position signal) detected by the conveyance position sensor 34 is transmitted to the controller 40 .

In the hollow part of the cylindrical roll 23, a scanner 10 is arranged for scanning the laser light L directed toward the continuous body of diapers 1', which is the object to be processed, in the X and Y directions. Here, as shown in FIG. 3, the scanner 10 has a galvanometer optical system composed of a light source (laser oscillator) 11 that emits a laser beam L, a condenser lens 12, an X-axis galvanometer 13 and a Y-axis galvanometer 14. I have it. As the light source ₁₁ for emitting the laser beam L, a suitable _one is used according to the type of workpiece and the purpose of irradiation. A laser, fiber laser, or the like is used.

The condensing lens 12 is for realizing constant-speed scanning of the laser light L. As shown in FIG. The X-axis galvanometer 13 is for scanning the laser light L that has passed through the condenser lens 12 in the X direction (the conveying direction of the diaper continuous body 1', which is the workpiece). The Y-axis galvanometer 14 is for scanning the laser light L in the Y direction (the direction along the opening 27 of the support member 21). Here, the condenser lens 12 is fixed on a Z-axis stage 16 movable in the X-axis direction by a Z-axis servo driver 15 . The X-axis galvanometer 13 has a scan mirror 19a that is rotationally driven by an X-axis servomotor 17. As shown in FIG. Similarly, the Y-axis galvanometer 14 has a scan mirror 19b rotationally driven by the Y-axis servomotor 18. As shown in FIG. The laser light L is reflected by the scan mirrors 19a and 19b and scanned along the X and Y directions. The X-axis servomotor 17 and the Y-axis servomotor 18 for rotating the scan mirrors 19a and 19b are driven and controlled by an XY-axis servo driver 41. FIG. This XY axis servo driver 41 is connected to the controller 40 . Further, the X-axis servomotor 17 is provided with an encoder (scanning position sensor) 42 for detecting the scanning position of the laser light L in the X-axis direction (conveying direction of the diaper continuous body 1' as the workpiece). . This encoder 42 is connected to the controller 40 .

As indicated by the velocity vector shown in FIG. 4, the continuous diaper 1', which is the object to be processed, moves in the X direction at a velocity v1 from time t3, which will be described later. Therefore, in order to scan the laser light L at the speed v3 along the slit-shaped opening 27 formed in the support member 21, the laser light L must be scanned at the speed v2' from time t3 to time t4, which will be described later. It must be emitted obliquely.

In this embodiment, the conveying position information (I) of the cylindrical roll 23 (workpiece) obtained by the conveying position sensor 34, the scanning position information (II) of the scanner 10 obtained by the encoder 42, and the dog sensor 33 Based on the reference position information (III) common to the cylindrical roll (conveying device) 23 and the scanner 10 obtained by the above, the conveying position of the cylindrical roll 23 (continuous diaper 1') is calculated. Specifically, the conveying position of the portion corresponding to the opening 27 of the cylindrical roll 23 in the diaper continuous body 1' being conveyed is calculated.

Along with calculating the conveying position, the X-direction scanning position of the laser beam L on the cylindrical roll 23 is calculated based on the conveying position information (I), the scanning position information (II), and the reference position information (III). Then, based on the difference between the conveying position and the scanning position, the deviation amount of the laser light L from the conveying position of the portion corresponding to the opening 27 in the continuous diaper 1' is obtained. In this embodiment, the sensors 33, 34, and 42 can be used to efficiently detect the displacement of the irradiation position of the laser light L with simple equipment. In the present embodiment, it is determined whether or not the irradiation of the laser light L is properly performed based on this amount of deviation.

The timing charts of FIGS. 5(a) to 5(d) show the transport position of the cylindrical roll 23 (diaper continuous body 1′), the scanning position of the laser light L in the X direction, the dog signal, and the time change of the calculation and judgment period. ing. As shown in the figure, at the timing when the dog sensor 33 detects the dog 32 (shown as "Slit 1", "Slit 2", etc. in FIG. Detecting the position of the body 1′) is started, and the encoder 42 starts detecting the scanning position of the laser light L in the X direction.

In the controller 40, the conveying position information (sensor value) (I) of the cylindrical roll 23 (work piece) obtained by the conveying position sensor 34 and the scanning position information (I) of the scanner 10 in the X direction obtained by the encoder 42 ( Based on the sensor value) (II) and the reference position information (dog signal) (III) common to the cylindrical roll (transport device) 23 and the scanner 10 obtained by the dog sensor 33, the cylindrical roll 23 (diaper continuous body 1 ') and the scanning position x2 of the laser beam L on the cylindrical roll 23 in the X direction are calculated by the following equations.

x1=coefficient α×conveyance position sensor value±offset amount γ (1)
x2=coefficient β×scan sensor value in X direction±offset amount δ (2)
Here, the coefficients α and β are coefficients for converting the sensor values into the conveying position on the common reference plane of the cylindrical drum and the scanning position. The offset amounts .gamma. and .delta. are correction amounts for quantitative deviations such as response delay inherent in the sensor and sensor installation position offset.

The conveying position x1 of the cylindrical roll 23 (continuous diaper 1') moves linearly with the lapse of time t in the detection cycle T of the adjacent dogs 32, as indicated by the straight line A in FIG. 5(a). Here, the inclination angle θ1 (tan θ1=dx1/dt) of the straight line A shown in FIG. 5 indicates the conveying speed v1 (see FIG. 4) of the cylindrical roll 23 (diaper continuous body 1'). Also, S in FIG. 5(a) indicates the distance (see FIG. 3) between adjacent dogs 32 (openings 27).

The scanning position x2 in the X direction of the laser beam L changes with the lapse of time t in the detection period T of the adjacent dogs 32, as indicated by the polygonal line in FIG. 5(b). As shown in FIG. 5(b), the scanner 10 starts scanning the laser light L in the X direction with a delay of Δt from the dog detection time t1 due to pre-operation processing of the X-axis galvano 13. occurs, and the X-axis galvanometer 13 starts moving to the scan position at time t2. The X-axis galvanometer 13 starts scanning at time t3 and finishes scanning at time t4. After completing the scanning, the X-axis galvanometer 13 returns to the standby position. Therefore, the laser beam L is irradiated along the opening 27 for a period of time (t4-t3), fuses the diaper continuous body 1' which is the object to be processed, and cuts the pants-type disposable diaper 1 (Fig. 1 and 2) is formed. Here, the scanning position x2 of the laser light L in the X direction moves linearly with the lapse of time t as indicated by straight line B in FIG. 5(b). In this case, the inclination angle θ2 (tan θ2=dx2/dt) of the straight line B indicates the scanning speed v2 of the laser light L in the X direction.

In the controller 40, based on the difference Δx obtained by the following expression (3) from x1 and x2 obtained by the above expressions (1) and (2), the diaper continuous body (workpiece) 1' of the laser beam L is calculated. Find the amount of deviation for

Δx=|x1−x2| (3)
When the deviation amount Δx is obtained by the above equation (3), the controller 40 determines whether or not the irradiation of the laser light L is properly performed based on this deviation amount Δx. Specifically, the controller 40 determines that the irradiation of the laser light L is properly performed when the deviation amount Δx is within a predetermined threshold value. The controller 40 determines that the irradiation of the laser light L is not properly performed when the deviation amount Δx exceeds a predetermined threshold value. The calculation of x1, x2 and the amount of deviation Δx, and the determination of the amount of deviation Δx are performed multiple times in each detection cycle T and the determination cycle ΔT, as shown in FIG. 5(d). However, during the period from t1 to t3 when laser irradiation is not actually performed and from t4 to the detection of the next dog signal, the deviation amount .DELTA.x determination is not performed.

FIGS. 6(a) to 6(c) show examples of temporal changes in the transport position x1 and the scan position x2. As shown in FIG. 6(a), when x1 and x2 match (x1=x2), the amount of deviation Δx becomes Δx=0, so the irradiation of the laser light L is performed properly. is judged.

The example shown in FIG. 6B shows a state in which a deviation amount Δx (≠0) has occurred between x1 and x2 due to a deviation in the timing of starting scanning of the laser light L. In the example shown in FIG. The solid line in the figure indicates the case of x1>x2, and the dashed line indicates the case of x1<x2. In this case, the conveying speed v1 of the cylindrical roll 23 (continuous diaper 1') and the scanning speed v2 of the laser light L in the X direction are the same (v1=v2).

Furthermore, in the example shown in FIG. 6(c), since the conveying speed v1 of the cylindrical roll 23 (continuous diaper 1′) and the scanning speed v2 of the laser light L in the X direction are different, the deviation amount Δx (≠0) is The solid line in the figure indicates the case where x1>x2, and the dashed line indicates the case where x1<x2. In FIG. 6C, the solid line indicates v1>v2, and the dashed line indicates v1<v2.

Next, the procedure of the processing method using laser light according to the present invention will be described below based on the flowchart shown in FIG.

When the processing (melting) of the continuous diaper 1', which is the object to be processed, by the laser beam L is started (step S1), it is determined whether or not the dog 32 is detected by the dog sensor 33 (step S2). When the dog 32 is detected by the dog sensor 33 (step S2: Yes), the scanner 10 moves the position to irradiate the laser light L to the irradiation start point (step S3), and then the scanner 10 starts irradiating the laser light L. (step S4). Then, the controller 40 calculates x1 and x2 by the above equations (1) and (2), respectively, and obtains the deviation amount .DELTA.x by the above equation (3) (step S5). Then, it is determined whether or not the obtained deviation amount Δx is within a predetermined threshold value (step S6). If the deviation amount Δx is within the threshold value (step S6: Yes), it is determined whether or not to end scanning (step S7). If the scanning is not to be finished (step S7: No), the process returns to step S5. An "OK" signal indicating that the processing is good is output (step S8). Next, the scanner 10 moves the laser beam L irradiation position to the standby position (step S9). Thereafter, it is determined whether or not the processing has been completed for all the products (step S10), and if the processing has been completed (step S10: Yes), the controller 40 ends the processing (step S14) If the processing of all the products has not been completed yet (step S10: No), the controller 40 repeats the processing of steps S2 to S10.

On the other hand, if the amount of deviation Δx exceeds the predetermined threshold in the determination in step S6 (step S6: No), it is determined that the irradiation of the laser beam L is not properly performed, and the processing defect is detected. An "NG" signal is output (step S11). Next, it is determined whether or not the cylindrical roll 23 has rotated by the set rotation amount based on each slit-shaped opening (step S12). Regarding the rotation of the cylindrical roll 23 for the set number of rotations set in advance, if it is determined that it is "NG" continuously at the same slit-shaped opening (step S12: Yes), the irradiation of the laser light L is properly performed. The irradiation position of the laser beam L by the scanner 10 is corrected for each slit-shaped opening (step S13). Next, the scanner 10 moves the laser beam L irradiation position to the standby position (step S9). After that, the controller 40 determines whether or not the machining has been completed for all the products (step S10), and if the machining has been completed for all the products (step S10: Yes), the process ends. (Step S14), and if not completed (Step S10: No), the processing of Steps S2 to S10 is repeated. On the other hand, if it is determined that the cylindrical roll 23 has not yet rotated the set number of rotations based on each slit-shaped opening (step S12: No), the process proceeds to step S2.

As described above, according to the laser beam processing method according to the present embodiment, the irradiation position of the laser beam L can be determined efficiently with simple equipment using the transport position sensor 34 and the encoder 42 without providing an imaging device. It is possible to detect the amount of deviation, and obtain the effect of being able to process (melt and cut) the diaper continuous body 1', which is the object to be processed, with high precision.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments. For example, in the above-described embodiment, the cylindrical drum type laser bonding apparatus 20 that rotates and conveys the workpiece (continuous diaper 1') by the cylindrical roll 23 has been described, but the present invention is applicable to the workpiece. The present invention is also applicable to a processing method using a laser beam that is carried out in a conveyor-type laser bonding apparatus that carries straight forward.

In the above description, the article to be processed is the diaper continuous body 1' of the underpants-type disposable diaper 1, which is one of strip-shaped sheet laminates. It can be applied to other absorbent articles such as sanitary napkins as a body, and can be widely applied to articles that can be processed by irradiation with laser light.

Furthermore, in the above embodiment, the conveying position information of the cylindrical roll 23 was acquired from the encoder signal from the linear encoder (not shown) installed on the peripheral surface of the cylindrical roll 23. (not shown), the conveying position information of the cylindrical roll 23 may be obtained based on an encoder signal from an encoder 31 (see FIG. 3) provided in the drive motor 30 that drives the cylindrical roll 23 to rotate.

1 Pants-type disposable diaper (sheet fused body)
1' diaper continuous body (workpiece, sheet laminate)
REFERENCE SIGNS LIST 10 scanner 11 light source 13 X-axis galvano 14 Y-axis galvano 20 laser bonding device 21 supporting member 23 cylindrical roll (conveying device)
27 opening 32 dog 33 dog sensor 34 transfer position sensor 40 controller L laser light Δx deviation amount

Claims (7)

A laser beam processing method for processing a workpiece conveyed by a conveying device at a predetermined speed by irradiating the workpiece with a laser beam emitted from a light source while scanning the workpiece with a scanner,
Conveying position information obtained by a sensor that detects the conveying position of the conveying device, scanning position information obtained by a sensor that detects the scanning position of the scanner, and reference position information common to the conveying device and the scanner. Based on this, the transport position of the transport device is calculated, the scanning position of the workpiece in the transport direction of the laser beam on the transport device is calculated, and the laser beam is calculated based on the difference between the transport position and the scanning position. A processing method using a laser beam for determining the amount of deviation of the light from the workpiece. 2. The processing method using a laser beam according to claim 1, wherein it is determined that the machining is good if the amount of deviation is within a predetermined threshold value, and that the machining is defective if the amount of deviation exceeds the threshold value. 3. The method according to claim 1, wherein the amount of deviation between said transport position and said scan position is due to delay or advance of one of said transport position and said scan position with respect to the other by a fixed amount, a fixed ratio, or a combination of both. A processing method using the described laser beam. 4. The method according to any one of claims 1 to 3, wherein a position correction amount is obtained by calculating a difference between said transport position and said scanning position, and the irradiation position of the laser beam by said scanner is corrected based on the obtained position correction amount. A processing method using a laser beam. 5. The processing method using laser light according to claim 4, wherein the correction of the irradiation position of the laser light is performed only when a deviation amount between the transport position and the scanning position exceeds a threshold value. 6. The processing method using a laser beam according to claim 1, wherein said conveying device is of a conveyor type that conveys said workpiece straightly or a cylindrical drum type that rotationally conveys said workpiece. 7. The processing method using a laser beam according to claim 1, wherein the processing using the laser beam is at least one of fusion between sheets in a strip-shaped sheet laminate and division of sheets.

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