阅读说明：本技术 模具面的激光清洗方法 (Laser cleaning method for die surface ) 是由 茂谷明宏 于 2020-02-20 设计创作，主要内容包括：本发明提供模具面的激光清洗方法,能够将激光的照射宽度设定得更宽,能够抑制清洗不均并且提高清洗效率。模具面的激光清洗方法包含根据模具面(2S)的三维侧面轮廓(PA)的数据,设定激光头(5)的移动动作和激光(L)的照射宽度(Lw)的示教工序。示教工序包含将三维侧面轮廓(PA)划分为呈沿第1坐标轴方向延伸的带状的多个清洗区域(Y)的步骤。在各清洗区域(Y)中,在沿着基准线(J)的深度方向上,清洗区域(Y)的最深部(ya)与最浅部(yb)的深度之差(Δh)分别为激光(L)的焦点深度的宽度(F)以下,所述基准线通过清洗区域(Y)的宽度中心(C)并与清洗区域(Y)的轮廓形状(PB)垂直。(The invention provides a laser cleaning method for a die surface, which can set the irradiation width of laser wider, inhibit uneven cleaning and improve cleaning efficiency. The method for laser cleaning a mold surface includes a teaching step of setting a movement operation of a laser head (5) and an irradiation width (Lw) of a laser beam (L) based on data of a three-dimensional side Profile (PA) of the mold surface (2S). The teaching process includes a step of dividing the three-dimensional side Profile (PA) into a plurality of cleaning regions (Y) in a band shape extending in the 1 st coordinate axis direction. In each cleaning region (Y), the difference (Deltah) between the depths of the deepest portion (ya) and the shallowest portion (yb) of the cleaning region (Y) in the depth direction along a reference line (J) that passes through the width center (C) of the cleaning region (Y) and is perpendicular to the contour shape (PB) of the cleaning region (Y) is equal to or less than the width (F) of the focal depth of the laser light (L).)

1. A method of cleaning a mold surface with a laser beam irradiated from a laser head, the method comprising:

a measuring step of measuring the mold surface to obtain a three-dimensional profile of the mold surface including pattern irregularities;

a teaching step of setting a movement operation of the laser head and an irradiation width of the laser beam based on the data of the three-dimensional profile; and

a cleaning step of cleaning the mold surface based on the movement and the irradiation width set in the teaching step,

the teaching step includes a step of dividing the three-dimensional contour into a plurality of cleaning regions which are in a band shape extending in a1 st coordinate axis direction and are used for cleaning with the laser light of the irradiation width,

in each of the cleaning regions, a difference (Δ h) in depth between a deepest portion and a shallowest portion of the cleaning region in a depth direction along a reference line passing through a width center of the cleaning region and perpendicular to a contour shape of the cleaning region not including the pattern unevenness is equal to or less than a width (F) of a focal depth of the laser light.

2. The method for laser cleaning a mold surface according to claim 1,

the mold surface is a mold surface of a tire vulcanization mold, and the 1 st coordinate axis direction is a tire circumferential direction.

3. The laser cleaning method of a mold surface according to claim 1 or 2,

the width (F) of the focal depth is 20 mm.

4. The method for laser cleaning a mold surface according to any one of claims 1 to 3, wherein,

the irradiation width of the laser is in the range of 10mm to 70 mm.

5. The method for laser cleaning a mold surface according to any one of claims 1 to 4, wherein,

an irradiation region of the laser light irradiating one of the cleaning regions adjacent to each other in a2 nd coordinate axis direction is partially overlapped with an irradiation region of the laser light irradiating the other cleaning region, and an overlapping width thereof is 3mm to 5mm, and the 2 nd coordinate axis direction is orthogonal to the 1 st coordinate axis direction.

6. The method for laser cleaning a mold surface according to any one of claims 1 to 5, wherein,

in the cleaning step, each of the cleaning regions is cleaned by performing laser irradiation for moving the laser beam having the irradiation width in the 1 st coordinate axis direction at least once.

7. The laser cleaning method of a mold surface according to claim 6,

in each of the cleaning regions, the number of times of the laser irradiation is plural.

8. The laser cleaning method of a mold surface according to claim 7,

the plurality of laser shots include a1 st laser shot in which an optical axis of the laser light is inclined at an angle + α with respect to the reference line in a2 nd coordinate axis direction and a2 nd laser shot in which an optical axis of the laser light is inclined at an angle- α with respect to the reference line in the 2 nd coordinate axis direction.

9. The laser cleaning method of a mold surface according to claim 8,

the 1 st laser irradiation is composed of laser irradiation in which an optical axis of the laser light is inclined at an angle + β in a1 st coordinate axis direction with respect to the reference line, and laser irradiation in which an optical axis of the laser light is inclined at an angle- β in the 1 st coordinate axis direction with respect to the reference line.

10. The laser cleaning method of a mold surface according to claim 8 or 9,

the 2 nd laser irradiation is composed of laser irradiation in which an optical axis of the laser light is inclined at an angle + β in the 1 st coordinate axis direction with respect to the reference line and laser irradiation in which an optical axis of the laser light is inclined at an angle- β in the 1 st coordinate axis direction with respect to the reference line.

Technical Field

The present invention relates to a laser cleaning method for cleaning a mold surface by laser light emitted from a laser head.

Background

For example, a vulcanization mold for a tire is repeatedly used, and dirt made of rubber, a mold release agent, or the like adheres to a mold surface. Such dirt is gradually accumulated, and if left standing, it adversely affects the molding accuracy and deteriorates the quality of the tire. Therefore, the mold surface needs to be cleaned periodically.

Patent document 1 proposes a cleaning system that irradiates a molding surface with a laser beam and that can efficiently remove dirt without requiring labor even for a molding surface having a complicated shape. In this cleaning system, when the mold is cleaned, three-dimensional image data of the molding surface of the mold is acquired by a camera, and laser light is irradiated while moving a laser head along the molding surface based on the acquired image data, thereby removing dirt adhering to the molding surface.

Patent document 1: international publication No. 2015/199113

In patent document 1, as conceptually shown in fig. 11, the laser head a is moved with a constant distance c kept in the vertical direction with respect to the molding surface b.

However, the focal depth of the laser is usually about ± 10mm, that is, the width of the focal depth is as narrow as about 20 mm. Therefore, when the mold is a mold for forming a tread, the depth change d1 of the uneven portion e for forming a tread groove formed on the molding surface b is within the width of the focal depth, and therefore, the mold can cope with this. However, the depth change d2 in the radial direction due to the tread profile shape f exceeds the width of the focal depth, and therefore cannot be dealt with.

Therefore, in patent document 1, a plurality of laser heads having different laser irradiation widths w are used, and a laser head having a small irradiation width w is used in a region where the depth change in the vertical direction is large (for example, a region on the shoulder side). Thus, the depth change in the irradiation region is suppressed within the width of the focal depth, and uneven irradiation and uneven cleaning are suppressed.

However, when the laser light is irradiated in the vertical direction, the height variation in the vertical direction in the molding surface becomes large. Therefore, the irradiation width of the laser light needs to be set narrower. As a result, the number of times of laser irradiation increases, which causes a problem of lowering cleaning efficiency.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a laser cleaning method for a mold surface, which can suppress variation in depth within an irradiation region within a width of a focal depth, set a laser irradiation width wider, suppress cleaning unevenness, and improve cleaning efficiency.

The present invention is a laser cleaning method for cleaning a mold surface with a laser beam irradiated from a laser head, the laser cleaning method including: a measuring step of measuring the mold surface to obtain a three-dimensional profile of the mold surface; a teaching step of setting a movement operation of the laser head and an irradiation width of the laser based on the data of the three-dimensional side profile; and a cleaning step of cleaning the mold surface based on the movement operation and the irradiation width set in the teaching step, wherein the teaching step includes a step of dividing the three-dimensional side profile into a plurality of cleaning regions each having a band shape extending in a1 st coordinate axis direction and used for cleaning with the laser light of the irradiation width, and in each of the cleaning regions, a difference Δ h between depths of a deepest portion and a shallowest portion of the cleaning region in a depth direction along a reference line passing through a width center of the cleaning region and orthogonal to a profile surface of the cleaning region is equal to or less than a width F of a focal depth of the laser light.

In the laser cleaning method of a mold surface according to the present invention, it is preferable that the mold surface is a mold surface of a tire vulcanizing mold, and the 1 st coordinate axis direction is a tire circumferential direction.

In the laser cleaning method of a mold surface of the present invention, it is preferable that the width F of the focal depth is 20 mm.

In the laser cleaning method of the die surface of the present invention, the irradiation width of the laser beam is preferably in a range of 10mm to 70 mm.

In the method of cleaning a mold surface with a laser beam according to the present invention, it is preferable that an irradiation region of the laser beam irradiating one of the cleaning regions adjacent to each other in the 2 nd coordinate axis direction partially overlaps an irradiation region of the laser beam irradiating the other cleaning region, and an overlapping width of the irradiation regions is 3mm to 5mm, and the 2 nd coordinate axis direction is orthogonal to the 1 st coordinate axis direction.

In the method for cleaning a mold surface according to the present invention, it is preferable that in the cleaning step, each of the cleaning regions is cleaned by performing laser irradiation for moving the laser beam having the irradiation width in the 1 st coordinate axis direction at least once.

In the laser cleaning method of a mold surface according to the present invention, it is preferable that the number of times of the laser irradiation is plural in each of the cleaning regions.

In the laser cleaning method of the die face according to the present invention, it is preferable that the plurality of times of laser irradiation include 1 st laser irradiation in which an optical axis of the laser light is inclined at an angle + α in a2 nd coordinate axis direction with respect to the reference line and 2 nd laser irradiation in which the optical axis of the laser light is inclined at an angle- α in the 2 nd coordinate axis direction with respect to the reference line.

In the laser cleaning method of the die face according to the present invention, it is preferable that the 1 st laser irradiation is composed of laser irradiation in which an optical axis of the laser light is inclined at an angle + β in a1 st coordinate axis direction with respect to the reference line and laser irradiation in which an optical axis of the laser light is inclined at an angle- β in the 1 st coordinate axis direction with respect to the reference line.

In the laser cleaning method of the die face according to the present invention, it is preferable that the 2 nd laser irradiation is composed of laser irradiation in which an optical axis of the laser light is inclined at an angle + β in a1 st coordinate axis direction with respect to the reference line and laser irradiation in which an optical axis of the laser light is inclined at an angle- β in the 1 st coordinate axis direction with respect to the reference line.

In the present invention, in a teaching process for setting a movement operation of a laser head and an irradiation width of a laser based on data of a three-dimensional side profile, the three-dimensional side profile is divided into a plurality of cleaning regions in a strip shape extending in a1 st coordinate axis direction. The cleaning region is a region for cleaning with laser light of an irradiation width.

In each of the cleaning regions, a difference Δ h between depths of a deepest portion and a shallowest portion of the cleaning region in a depth direction along a reference line that passes through a width center of the cleaning region and is orthogonal to a contour shape of the cleaning region is equal to or less than a width F of a focal depth of the laser light.

Therefore, by irradiating the laser light along the reference line, it is possible to set the irradiation width wider while suppressing the depth change within the irradiation region within the width F of the focal depth, as compared with the case of irradiating the laser light in the vertical direction. As a result, the cleaning efficiency can be improved while suppressing uneven cleaning.

Drawings

Fig. 1 is a conceptual diagram illustrating an embodiment of a laser cleaning apparatus for carrying out the laser cleaning method of the die surface of the present invention.

Fig. 2 is a perspective view showing one embodiment of the mold.

Fig. 3 (a) and 3 (b) are conceptual views illustrating the measurement step.

Fig. 4 is a perspective view showing a three-dimensional side profile of a cleaning region divided by a teaching process.

Fig. 5 is a partially enlarged view illustrating a cleaning region.

Fig. 6 is a conceptual diagram illustrating the cleaning process.

Fig. 7 (a) to 7 (c) are conceptual diagrams illustrating an example of a method of dividing the cleaning region in the teaching step.

Fig. 8 (a) and 8 (b) are conceptual views illustrating the 1 st laser irradiation and the 2 nd laser irradiation.

Fig. 9 (a) and 9 (b) are conceptual views showing laser irradiation at an angle + β forming the 1 st laser irradiation and laser irradiation at an angle- β forming the 2 nd laser irradiation.

Fig. 10 (a) to 10 (c) are conceptual diagrams illustrating another example of the method of dividing the cleaning region in the teaching step.

Fig. 11 is a conceptual diagram for explaining the problem of the present invention.

Description of the reference symbols

2S: a mold face; 5: a laser head; 30: laser irradiation; 30A: 1, laser irradiation; 30A 1: laser irradiation; 30A 2: laser irradiation; 30B: 2, laser irradiation; 30B 1: laser irradiation; 30B 2: laser irradiation; 31: irradiating the area; c: a width center; j: a reference line; l: laser; lw: irradiating width; PA: a three-dimensional side profile; PB: a profile shape; w31: an overlap width; y: cleaning the area; ya: a deepest portion; yb: a shallowest portion; Δ h: the difference in depth.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

As shown in fig. 1, a laser cleaning apparatus 1 for carrying out the laser cleaning method of the present invention includes: a mounting table 3 for holding the mold 2; a measuring means 4 for obtaining a three-dimensional profile of the mold surface 2S of the held mold 2; a laser head 5 for irradiating the mold surface 2S with laser light L; a multi-axis robot 6 for supporting the laser head 5; and a control device 7 for controlling the multi-axis robot 6 according to the data of the three-dimensional side profile.

In this example, the mold 2 is a tire vulcanizing mold, and particularly, the case where the mold 2 is a split mold 8 of a tread molding mold is shown. As shown in fig. 2, the split mold 8 includes a circular arc-shaped molding surface 8A for molding a tread of a tire and split surfaces 8B connected to both sides of the molding surface 8A in the tire axial direction. In this example, the molding surface 8A and the dividing surface 8B constitute a mold surface 2S to be cleaned. The parting plane 8B is a parting plane between the sidewall molds (not shown).

The molding surface 8A is formed with a convex portion 9 for forming a tread pattern. As the convex portion 9, for example, 3 circumferential ribs 9A extending in the tire circumferential direction and a plurality of lateral ribs 9B extending in a direction intersecting the circumferential ribs 9A are arranged. The convex portions 9 are formed according to a tread pattern.

As shown in fig. 1, the die 2 (split die 8) is held on the mounting table 3 with the die surface 2S facing upward. The mounting table 3 of the present example is a fixed table, and shows a case where the mold 2 is held at a predetermined position without movement. However, for example, in the case where the mold 2 is a sidewall molding mold, a turntable for supporting the sidewall molding mold rotatably about the tire axis may be used as the mounting table 3.

As the multi-axis robot 6, an industrial robot may be preferably employed. The multi-axis robot 6 of the present example includes, for example, a rotary table 11 disposed on a base portion and a robot arm 12 supported on the rotary table 11. The robot arm 12 is bendable by a plurality of fulcrums 12A, and the robot arm 12 includes a retractable arm portion 12B. This enables the laser head 5 attached to the distal end portion of the robot arm 12 to freely perform a three-dimensional movement operation.

As the laser head 5, various laser heads provided and sold by laser manufacturers can be employed. The laser head 5 scans the pulse light output from a laser oscillator (not shown) in the width direction with a built-in mirror, and thereby can adjust the irradiation width Lw of the laser light L in a range of, for example, 10mm to 70 mm. The irradiation width Lw is a width of the laser light L in a direction perpendicular to the optical axis.

The laser head 5 of this example has a focal depth of, for example, ± 10 mm. That is, the width F of the focal depth is 20 mm. Therefore, the laser light L can apply substantially uniform energy at the depth of focus, and uneven irradiation and uneven cleaning can be suppressed.

The measuring means 4 measures the die surface 2S of the die 2 held on the mounting table 3 to obtain a three-dimensional side profile PA thereof (as shown in fig. 3 (b)). The measuring member 4 may be any member as long as it can measure the three-dimensional shape of the mold surface 2S, and for example, various sensors and cameras may be used.

The "three-dimensional side surface profile PA" also includes a concave-convex shape formed by the convex portions 9 for forming a tread pattern. The "profile shape PB" described later is a virtual side profile that is smoothly connected by removing the uneven shape formed by the convex portions 9 in the three-dimensional side profile PA.

Next, a laser cleaning method using the laser cleaning apparatus 1 will be described. The laser cleaning method includes a measurement step, a teaching step, and a cleaning step.

The measuring step is a step of measuring the mold surface 2S by using the measuring member 4 to obtain the three-dimensional side profile PA thereof. In this example, a 3D laser sensor 4A is used as the measurement member 4. The 3D laser sensor 4A is attached to the robot arm 12 and can be moved to a free position.

As shown in fig. 3 a and 3 b, in the measurement step of this example, the mold surface 2S is scanned in the tire circumferential direction at a plurality of positions (for example, 3 positions) in the tire axial direction, and the measurement data D at each position is transmitted to the control device 7, which is a computer, for example. The controller 7 adds the measurement data D for each position to create a three-dimensional profile PA of the entire mold surface 2S.

In the teaching step, the movement operation of the laser head 5 and the irradiation width Lw of the laser L are set based on the data of the three-dimensional side profile PA.

As conceptually shown in fig. 4, the teaching process includes a step of dividing the three-dimensional side profile PA into a plurality of (5 in this example) cleaning regions Y in a band shape extending in the 1 st coordinate axis direction. The cleaning region Y is formed as a region to be cleaned by moving the laser light L having the irradiation width Lw set for each cleaning region Y in the 1 st axis direction. In fig. 3 to 9, for convenience, the three-dimensional side surface profile PA is drawn without the irregularities formed by the lateral ribs 9B.

In this example, the tire circumferential direction is set as the 1 st coordinate axis direction. Further, the tire axial direction is set as the 2 nd coordinate axis direction perpendicular to the 1 st coordinate axis direction.

Fig. 5 shows a portion of the three-dimensional side profile PA. As representatively shown in fig. 5, in each cleaning region Y, the difference Δ h in depth between the deepest portion ya and the shallowest portion yb of the cleaning region Y in the depth direction along the reference line J (hereinafter, sometimes referred to as "the reference line J direction") is set to be equal to or less than the width F of the focal depth of the laser light L. That is, in each cleaning region Y, the maximum Δ h of the depth change of the cleaning region Y in the direction of the reference line J (corresponding to the difference Δ h in depth) is set to be equal to or less than the width F of the focal depth.

The reference line J is defined as a line passing through the width center C of the cleaning region Y and perpendicular to the outline shape PB of the cleaning region Y. The width center C is a point at which a line equal to the distance between both ends (both ends in the 1 st coordinate axis direction) of the cleaning region Y, among lines perpendicular to the contour shape PB, intersects the three-dimensional side profile PA.

In this step, the three-dimensional side profile PA can be divided into the plurality of cleaning regions Y so that the maximum Δ h of the depth change of the cleaning region Y in the direction of the reference line J is suppressed to be equal to or less than the width F of the focal depth and the region width Yw of the cleaning region Y in the direction perpendicular to the reference line J is maximized. As a result, the cleaning efficiency can be improved while suppressing uneven cleaning due to the off-focal depth.

Here, an example of a method of dividing the cleaning region Y in the above-described step will be described. As shown in fig. 7 (a), one end of the three-dimensional side contour PA in the 2 nd coordinate axis direction is set as the start point Qa1, and the temporary width center C' is moved from the start point Qa1 to the other end side in the 2 nd coordinate axis direction on the three-dimensional side contour PA. Then, a temporary reference line J 'passing through the temporary width center C' and perpendicular to the outline shape PB is set for each movement. A point on the three-dimensional side contour PA which is apart from the provisional reference line J 'toward the other end by a distance equal to the distance between the provisional reference line J' and the starting point Qa1 is set as a terminal Qb 1. Then, the distance between the starting point Qa1 and the terminal point Qb1 is defined as a temporary cleaning region Y ', and the maximum Δ h' of the depth change in the direction of the temporary reference line J 'is obtained in the temporary cleaning region Y'. Then, the maximum Δ h ' is compared with the width F of the focal depth, and when Δ h ' < F, the provisional width center C ' is further moved to the other end side, and the above-described operation is sequentially repeated.

The temporary width center C' is preferably moved at predetermined intervals. The interval is preferably in the range of 1mm to 5mm, but in this example, 5mm is used from the viewpoint of computational efficiency. In addition, the movement of the temporary width center C' may be continuous.

Then, as shown in fig. 7 (b), of the temporary cleaning zones Y 'satisfying Δ h' ≦ F, the cleaning zone having the zone width Yw closest to the preset upper limit value Ywmax is set as the 1 st cleaning zone Y. As the upper limit value Ywmax of the region width Yw, an upper limit value (for example, 70mm) of the adjustment width of the laser light L is preferably used.

As shown in fig. 7 (C), the 2 nd cleaning region Y is formed by moving the temporary width center C' from the start Qa2 to the other end side with the end Qb1 of the 1 st cleaning region Y as the start Qa2 of the 2 nd cleaning region Y. Then, as in the case of the 1 st cleaning zone Y, the cleaning zone having the zone width Yw closest to the preset upper limit value Ywmax among the temporary cleaning zones Y 'satisfying Δ h' ≦ F is set as the 2 nd cleaning zone Y.

By repeating this operation in sequence, as shown in fig. 4, the three-dimensional side profile PA can be divided into a plurality of cleaning regions Y satisfying Δ h ≦ F and having the region width Yw that is the maximum value equal to or less than the upper limit value Ywmax.

Such calculation is automatically performed using a calculation program previously incorporated in the control device 7.

As shown in fig. 6, in the teaching step, the irradiation width Lw of the laser light L for irradiating the cleaning region Y is set for each cleaning region Y. The irradiation width Lw is not less than the region width Yw, preferably Lw > Yw, and more preferably the difference (Lw-Yw) is 3mm to 5 mm.

In the teaching step, the distance from the laser head 5 to the cleaning region Y is set for each cleaning region Y. Specifically, as shown in fig. 5, in each cleaning region Y, the position of the laser head 5 is set so that a position K on the reference line J and at which the height is 1/2 corresponding to the depth difference Δ h is focused.

In the cleaning step, as shown in fig. 6, the mold surface 2S is cleaned based on the movement operation of the laser head 5 and the irradiation width Lw of the laser light L set in the teaching step.

Specifically, the laser irradiation 30 is performed once or more for each cleaning region Y, and the laser irradiation 30 is performed by moving the laser light L having the irradiation width Lw set for the cleaning region Y in the 1 st coordinate axis direction (tire circumferential direction). In the laser irradiation 30, the cleaning region Y is irradiated with the laser light L while the optical axis is aligned with the reference line J or inclined at a small angle. The movement in the 1 st coordinate axis direction (tire circumferential direction) may be continuous or intermittent.

At this time, in each cleaning region Y, by making the irradiation width Lw larger than the region width Yw, the irradiation regions 31 of the laser light L adjacent in the 2 nd coordinate axis direction (tire axial direction) partially overlap with each other. This prevents uneven cleaning due to gaps between the irradiation regions 31. The overlapping width W31 between the irradiation regions 31 is preferably 3mm to 5 mm. If the thickness is less than 3mm, a gap may be generated due to an error or a working error. On the contrary, even if the overlap width W31 exceeds 5mm, the cleaning action does not change, but the cleaning process takes a long time. In addition, the overlap width W31 is defined as the width along the profile shape PB.

Here, when the laser light L is irradiated in each cleaning region Y so that the optical axis coincides with the reference line J, a shadow is generated by the convex portion 9 on the mold surface 2S depending on the tread pattern, and there is a possibility that a portion where dirt does not fall off is generated because the laser light L is not directly irradiated.

Therefore, in this example, the laser irradiation 30 is performed a plurality of times for each cleaning region Y. As shown in fig. 8 (a) and 8 (b), the multiple laser irradiation 30 includes: the 1 st laser shot 30A, for example, 2 times with the optical axis J of the laser light L inclined at an angle + α in the 2 nd coordinate axis direction with respect to the reference line J; and 2 nd laser shots 30B of, for example, 2 times, with the optical axis J of the laser light L inclined at an angle- α in the 2 nd coordinate axis direction with respect to the reference line J.

"+ α" indicates that the optical axis J is inclined by α degrees to one side (right side in the drawing) in the 2 nd coordinate axis direction with respect to the reference line J, and "— α" indicates that the optical axis J is inclined to the other side (left side in the drawing) in the 2 nd coordinate axis direction with respect to the reference line J.

As shown in fig. 9 (a) and 9 (b), the 1 st laser irradiation 30A of the 2 nd order is composed of a laser irradiation 30A1 and a laser irradiation 30A2, and the optical axis J of the laser light L is inclined at an angle + β in the 1 st coordinate axis direction with respect to the reference line J in the laser irradiation 30A1, and the optical axis J of the laser light L is inclined at an angle- β in the 1 st coordinate axis direction with respect to the reference line J in the laser irradiation 30A 2.

"+ β" indicates that the optical axis J is inclined by β degrees to one side (right side in the figure) of the 1 st coordinate axis direction with respect to the reference line J, and "— β" indicates that the optical axis J is inclined to the other side (left side in the figure) of the 1 st coordinate axis direction with respect to the reference line J.

In this example, the 1 st laser irradiation 30A of 2 times is performed by reciprocating the laser light L in the 1 st coordinate axis direction, the laser irradiation 30A1 is performed as irradiation on the forward side, and the laser irradiation 30A2 is performed as irradiation on the backward side.

Similarly, the 2 nd laser irradiation 30B of 2 times is composed of the laser irradiation 30B1 and the laser irradiation 30B2, and in the laser irradiation 30B1, the optical axis J of the laser light L is inclined at an angle + β in the 1 st coordinate axis direction with respect to the reference line J, and in the laser irradiation 30B2, the optical axis J of the laser light L is inclined at an angle- β in the 1 st coordinate axis direction with respect to the reference line J.

In this example, the 2 nd laser irradiation 30B of 2 times is performed by reciprocating the laser light L in the 1 st coordinate axis direction, the laser irradiation 30B1 is performed as irradiation on the forward side, and the laser irradiation 30B2 is performed as irradiation on the backward side.

As in this example, by performing the laser irradiation 30 on each cleaning region Y for a total of 4 times with the optical axis j being (+ α, + β), (+ α, - β), (- α, + β), (- α, - β), the occurrence of cleaning unevenness due to shading or the like can be suppressed.

In addition, | α |, | β | are set according to the type of the mold. For example, in the case of a tread molding die for a summer tire having a less complicated tread pattern, | α | is preferably in the range of 5 ° to 10 °, and | β | is preferably in the range of 10 ° to 15 °. In the case of a tread molding die for a snow tire and a studless tire having a large number of sipes, | α | is preferably in the range of 3 ° to 5 °, and | β | is preferably in the range of 3 ° to 5 °. In the case of the side wall mold, | α | is preferably in the range of 5 ° to 10 °, and | β | is preferably in the range of 10 ° to 20 °.

It is preferable that the determination of the type of the mold is performed by providing the mold with information on the type of the mold in advance using an identification system such as RFID (radio frequency identification) and automatically reading the information. It is also preferable that the control device 7 be incorporated with a calculation program for automatically determining the type based on the uneven cycle of the three-dimensional side profile PA obtained in the measurement step.

As shown in fig. 10 (a) to 10 (c), another example of a method of dividing the three-dimensional side profile PA into a plurality of cleaning regions Y in the teaching process is shown.

In this example, the provisional cleaning region Y' is set temporarily by moving the terminal Qb1 to the other end side in the 2 nd coordinate axis direction on the three-dimensional side contour PA with one end in the 2 nd coordinate axis direction of the three-dimensional side contour PA as the starting point Qa 1. Then, the maximum Δ h ' of the depth change in the direction of the provisional reference line J ' is obtained in the provisional cleaning region Y ', and is compared with the width F of the focal depth. The provisional reference line J' is defined as a line equidistant from the start point Qa1 and the end point Qb1, out of the lines perpendicular to the outline shape PB. Then, when Δ h' < F, the terminal Qb1 is moved further to the other end side, and the above-described operation is sequentially repeated. The movement of the terminal Qb1 is preferably performed at a predetermined interval as in the case of the width center C, and the interval is preferably in the range of 1mm to 5 mm. In addition, the movement of the temporary width center C' may be continuous.

Then, as shown in FIG. 10 (b), a cleaning zone having a zone width Yw closest to a preset upper limit value Ywmax (for example, 70mm) among the temporary cleaning zones Y 'satisfying Δ h' ≦ F is set as the 1 st cleaning zone Y.

As shown in fig. 10 (c), as the 2 nd cleaning region Y, the terminal Qb1 of the 1 st cleaning region Y is set as the start end Qa2 of the 2 nd cleaning region Y, and the terminal Qb2 is moved from the start end Qa2 to the other end side to temporarily set a temporary cleaning region Y'. Then, as in the case of the 1 st cleaning zone Y, the cleaning zone having the zone width Yw closest to the preset upper limit value Ywmax among the temporary cleaning zones Y 'satisfying Δ h' ≦ F is set as the 2 nd cleaning zone Y.

By repeating this operation in sequence, the three-dimensional side profile PA is divided into a plurality of cleaning regions Y.

While the above description has been made in detail with respect to the particularly preferred embodiments of the present invention, the present invention is not limited to the illustrated embodiments, and can be modified into various embodiments.