JP2008062633A - Cleaning method and cleaning apparatus of mold using laser beam machining, and cleaning apparatus of tire shaping mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove a residue adhering to a shaping mold of a rubbery tire or the like exactly in a short time without deformation of a major material of the mold by heat. <P>SOLUTION: The apparatus has a work placement table on which an item to be cleaned is placed, a manipulator arranged above the work placement table and having multi-joints of at least two joints, a laser head arranged at the tip end of the manipulator, a laser oscillator supplying a laser beam to the laser head, an optical element mounted on the laser head and irradiating the laser beam to the item to be cleaned, and a controller moving the manipulator along the shape of the item to be cleaned. The laser oscillator emits CO2 laser and other short laser beam, and the manipulator moves the laser head along the concave and convex shape formed on the item to be cleaned. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molding die cleaning method and apparatus used for molding various synthetic resins, vulcanizing synthetic rubber, and the like, and more particularly, to cleaning a molding die that forms a fine surface shape of a rubber tire or the like.

  In general, molding of synthetic resin, etc. is widely used for molding various parts, equipment casings, and other raw materials into the mold and cooling and solidifying. In addition, vulcanization molding of rubber tires is heated by filling the mold with liquid rubber. Vulcanization molding methods are widely known. A processing method for producing a product with such a mold is widely used regardless of molding or vulcanization, and is known as equipment for continuous mass production.

Conventionally, when a rubber tire is produced with such a mold, for example, a mold release agent is used so that a residue such as a material does not remain in the mold. In this case, it is inevitable that the organic substance) adheres to the mold surface or grooves and hardens. When a residue such as a raw material adheres to such a mold surface, it affects the molding shape. For example, in the case of a rubber tire, there is a problem that the shape of the tire pattern on the tire surface changes. Therefore, in the manufacturing process, the surface of the molding die is cleaned (polished) in a timely manner to remove the adhered substances.
Conventionally, this mold has been cleaned by (1) manual cleaning using an abrasive (hereinafter referred to as “abrasive”), (2) dry ice blast cleaning for shot blasting dry ice pellets, and (3) under reduced pressure. There are known plasma cleaning in which H2O plasma is generated by irradiating microwaves to decompose and clean, and (4) laser cleaning in which attached substances are removed by shock waves generated by irradiating laser light.

For example, Patent Document 1 discloses an apparatus as shown in FIG. In this document, a plurality of molds for vulcanizing and molding rubber tires are arranged in the apparatus, an optical scanning device (laser irradiator) is arranged inside the mold, and laser light is emitted from the irradiator. . Then, by rotating this irradiator 360 degrees, the residue adhering to the mold surface is removed by washing.
Conventionally, a YAG laser (wavelength: 1.064 μm) is used as the laser beam. Since this YAG laser has a relatively short wavelength, optical fiber transfer from a laser oscillator to a laser head for irradiating the laser is possible, and the optical system of the apparatus can be downsized. Thus, it is generally considered that the removal of residues such as molds using laser light has the following characteristics.
1. Do not use chemicals or blasting materials Because only optical energy is used, the amount of waste is greatly reduced.
2. 2. It must be a dry process. Work must be done in a dry environment, maintaining a hygienic environment. Do not damage the base metal (die) The parameters are different from those of the welding / cutting laser and do not affect the metal base such as the metal mold. (The maximum surface temperature is about 200 ° C)
4). There are no flying objects. There is little influence of flying objects on the surrounding environment and operators.
There is no need to set up a shatterproof net in the work area, and no curing is required.
5. Being non-contact Adopting a non-contact cleaning method that uses only laser light, no special tools are required.
6). 6. No noise There is no worry about noise in the work environment and the surrounding environment. Low running cost Since no chemicals, water, blasting materials, etc. are used, the running cost is greatly reduced. Easy to automate
JP-A-9-327832 (FIG. 1)

  As described above, it is already known to wash and remove residues (residues) adhering to a rubber tire vulcanization mold (hereinafter referred to as a mold) with a laser beam, and it is also known to have the above-described characteristics. However, conventionally, as disclosed in the above-mentioned Patent Document 1, a laser beam having a relatively short wavelength, such as a YAG laser, is guided to a laser head by an optical fiber or the like, and the mold surface is irradiated from this head. There is.

  First, a relatively short wavelength laser beam (such as a YAG laser) is emitted with a long pulse, and this is irradiated onto the mold, so it is formed on the mold when the mold is made of a metal such as an aluminum alloy. In other words, the short wavelength YAG laser (wavelength 1.064 μm) has a large absorptivity with respect to the aluminum alloy, so that there is a problem that the shape is deformed by heat transmitted to the mold itself. In the case of a mold, the residue of the rubber material to be cleaned is an organic substance, whereas the absorption rate of the mold itself is larger than this residue, so that the tire pattern formed on the surface may be deformed by heat. The laser beam with light energy could not be irradiated, and the rubbery residue could not be peeled off reliably.

In addition, conventionally, since the entire surface is irradiated with the laser light under the same conditions regardless of the uneven shape formed on the mold surface as in the above-mentioned Patent Document 1, for example, a residue adhering in an uneven groove such as a tread pattern It is necessary to irradiate the laser beam for a long time to completely remove the metal. On the other hand, there is a problem that the mold base material is deformed by the laser beam irradiation for a long time.
As described above, the wavelength band that can be transmitted through the optical fiber (mainly the wavelength of the YAG laser) has a large transmission loss and is basically a condensed beam, and therefore the irradiation area is small. This is several times to several tens of times that the processing time (cleaning time) required for completely removing the residue is required. In addition, there is a problem that it is difficult to remove residues attached to the grooves such as tread patterns.

  Therefore, the present invention has a large absorption rate for organic substances adhering to a mold or the like, and a long-wavelength laser such as a short pulse Co2 laser capable of properly irradiating a pattern groove such as an uneven shape on the mold surface. This is based on the idea that residues can be peeled and removed reliably in a short time by using light and simultaneously irradiating laser light along a complicated pattern shape.

Accordingly, the main object of the present invention is to provide a cleaning method and a cleaning apparatus capable of removing residues adhering to a molding die such as a rubber tire in a short time without deforming the die itself by heat or the like. Yes.
Another object of the present invention is to provide a cleaning apparatus capable of irradiating a laser beam in accordance with the shape of a groove pattern or the like formed on an object to be cleaned such as a mold. Another object of the present invention is to provide a simple control system that tracks and irradiates a laser head that irradiates a laser beam with a complicated shape of an object to be cleaned.

The present invention employs the following configuration in order to solve the above problems.
The present invention applies a short pulse (for example, a pulse width) to a deposit (hereinafter referred to as “residue”) of a molding die such as a rubber tire (hereinafter referred to as “residue”) or a Co 2 laser having a high absorption rate with respect to an organic substance such as rubber material. Is irradiated at 10 [mu] Sec to 100 [mu] Sec). As a result, it is possible to reliably peel off and remove organic residue adhering without deforming the mold itself. Further, the present invention is characterized in that the Co2 laser is irradiated along a groove pattern such as a mold. For this reason, the manipulator is equipped with a laser head that emits laser light, and the manipulator is controlled so that the laser head tracks the groove pattern. This makes it possible to clean the mold at a high speed in a short time.
The present invention is characterized in that the groove shape is tracked by a manipulator having at least two articulated arms when the laser beam is irradiated along the groove pattern of the object to be cleaned. A laser head that irradiates laser light to the tip of the articulated arm is provided, and a laser oscillator is provided at the other end of the arm. The three-dimensional position of the laser head and the light emission pattern of the laser oscillator are controlled according to the groove shape. As a result, the object to be cleaned having a complicated shape can be irradiated with laser light in accordance with the place where the deposit is attached, and the deposit can be more reliably peeled and cleaned.

  Furthermore, the present invention is characterized in that when the laser beam is tracked along the groove pattern, the laser beam is irradiated as a predetermined length of line light (striated light). For this reason, a cylindrical lens and / or a polygon mirror or a galvanometer mirror is arranged in the laser head, and by irradiating a line-shaped laser beam formed into a line along the groove pattern, the laser beam is compared with a spot-shaped beam beam. Cleaning at high speed and in a short time. In the present invention, the manipulator is controlled by original shape data (cad data, etc.) of an object to be cleaned, such as a mold, and laser head position correcting means (input means, etc.). As a result, the manipulator can be easily controlled, and the cleaning operation can be easily performed without requiring skill.

  The present invention is characterized in that when the manipulator is controlled, the irradiation position of the laser head and the removal state of the residue are monitored. This monitoring is configured so that, for example, the center of the optical element (lens) that irradiates the laser beam and the plume from which the deposit is generated can be visually recognized. As a result, it is possible to control the position of the laser head by confirming whether the laser beam is accurately irradiated along the groove pattern and whether the deposits have been removed reliably.

Since the present invention is designed to remove the residue adhered by irradiating the object to be cleaned such as a rubber tire vulcanizing mold with a Co2 laser, the absorption rate for organic matter is higher than that for the conventional YAG laser and it is suitable for the metal. Since the absorption rate is low, organic substances such as rubber can be reliably removed, and at the same time, a mold base material such as an aluminum alloy is hardly deformed.
In addition, since a Co2 laser is irradiated with a short pulse (for example, a pulse width of 10 μSec to 100 μSec), a strong shock wave is generated in an uneven groove such as a tread pattern of a tire, and a residue attached thereto can be peeled and removed. Become.

  Furthermore, since the present invention irradiates the object to be cleaned with the above-mentioned Co2 laser as a linear beam, it is possible to perform cleaning at a higher speed than the case of irradiating the conventional spot-shaped beam light. It is also possible to generate according to the concavo-convex shape, and in this case, further high-speed cleaning is possible. In the present invention, the above-described laser head that oscillates the Co2 laser light is arranged at the tip of a manipulator having at least two articulated arms, and a laser oscillator is arranged at the base end of the manipulator. Therefore, the attached residue can be reliably removed by irradiating the laser head while moving so as to follow the uneven shape formed on the object to be cleaned. Furthermore, it is possible to automatically clean based on the original shape data of the object to be cleaned.

  The present invention will be described in detail below based on the embodiments shown in the drawings. FIG. 1 shows the shape of a rubber tire vulcanization mold as an embodiment of an object to be cleaned. FIG. 2 is an explanatory view of the entire configuration of the cleaning apparatus of the present invention, FIG. 3 is a detailed explanatory view of the laser head portion, and FIG. 4 is a detailed explanatory view of an articulated arm portion. FIG. 5 is a model diagram of the filament laser beam.

  As shown in FIG. 1, a mold 1 used for vulcanization molding of a rubber tire or the like has a cylindrical shape and is formed into a normal rubber tire shape, and a groove pattern 1a that forms a tire pattern is formed inside. And in this mold 1, the original form of the tire (green tire) formed by molding each part such as carcass, belt, tread, bead, etc., is housed, the green tire is put into the mold, and high temperature / high pressure steam is put in Press toward the mold from inside with a bladder (compressor). At this time, rubber molecules and sulfur molecules are bonded by heat and pressure, and the elasticity and durability of the green tire rubber is born. Further, the final shape of the tire and the pattern of the tread surface (hereinafter referred to as “tread pattern”) are also formed by the mold at this time.

  When such vulcanization is repeated, rubber material, sulfur and other additives adhere to the mold 1 (hereinafter, this deposit is referred to as “residue”). This residue adheres to the mold under high temperature and high pressure, for example, in a groove of a tread pattern. When such residue sticking progresses, the tread pattern 1a collapses, making it impossible to produce a uniform and high-quality tire. The mold 1 needs to be cleaned to remove residues at appropriate times, and the present invention relates to a cleaning apparatus and a cleaning method for such an object to be cleaned (hereinafter collectively referred to as a mold).

First, the cleaning apparatus of the present invention will be described.
As shown in FIG. 2, the cleaning device A includes a workpiece mounting table 2, a laser oscillator 3, a manipulator 4, and a control device 5. The laser oscillator 3 is composed of an oscillator main body, and the structure thereof is not described in detail, but employs a structure that oscillates ordinary Co2 laser light with a predetermined pulse. In particular, the oscillator body 3 is configured to oscillate the Co 2 laser light with a short pulse having a pulse width of 10 μSec to 100 μSec. At the exit end of the oscillator, a condenser lens is configured to emit a point light source with a long focal lens.
The short pulse oscillation was used to reduce the influence of heat on a base material such as metal (such as a mold), and a range of 10 to 100 μsec was preferred from experiments. The workpiece mounting table 2 is a table on which an object to be cleaned (mold) 1 is mounted, and the configuration thereof is configured in an appropriate shape for mounting the object 1 to be cleaned in a predetermined posture. In particular, it is preferable that the workpiece mounting table 2 is provided with clamping means for holding the object to be cleaned (mold) 1 in a stationary state. The oscillator body 3 incorporates a homogenizer as necessary to make the energy distribution of the laser light uniform. This makes it possible to obtain a polishing action stably with the same energy on the object to be cleaned.

  The manipulator 4 includes a driving side manipulator 41 and a driven side manipulator 42. The driven side manipulator 42 includes at least two joints, and the illustrated one includes an articulated arm 42a connected by connecting shafts 43a, 43b, and 43c. The laser oscillator 3 is optically connected to the base end portion. Although not shown in the drawings, each of the connecting shaft portions 43a, 43b, and 43c is provided with two mirrors arranged opposite to each other so as to be able to rotate 360 degrees with respect to the reflection shaft. The CO2 laser light is transmitted to the distal end head 6 by combining a hollow optical path formed in each arm portion 44a, 44b, 44c, 44d with a fixed mirror and a rotating mirror at its node. In other words, the mirror that reflects at 45 degrees is fixed, and the mirror that can rotate 360 degrees is opposed to each other so that the angle of the node can be freely set.

  A laser head 6 having a cylindrical lens and / or a polygon mirror or a galvanometer mirror (not shown) for irradiating the mold 1 with laser light from the laser oscillator 3 is provided at the distal end of the driven manipulator 42. Yes. This polygon mirror, galvanometer mirror, or cylindrical lens is configured to apply substantially uniform energy regardless of the uneven shape of the object to be cleaned at a long focal depth (± 4 mm in the figure). The laser beam transmitted to the cylindrical lens via the articulated arm is converted into a predetermined length of filament light by a polygon mirror or a galvanometer mirror, and is irradiated on the object to be cleaned. For this purpose, the laser head 6 incorporates a polygon mirror or galvanometer mirror, a drive motor for rotating the mirror, and a cylindrical lens. And it is comprised so that adjustment of the length of the filament light irradiated to a to-be-cleaned object by control of this drive motor is possible.

  As shown in FIG. 5, the laser beam from the laser head irradiates the mold 1 which is the object to be cleaned with the filament light P. The laser head 6 is arranged above the workpiece mounting table 2 and is configured to be freely movable at a three-dimensional position. On the other hand, the driving side manipulator 41 is composed of at least two connecting shafts, and the illustrated one is composed of connecting shafts 45 a and 45 b, and the front end portion thereof is connected to the front end portion of the driven side manipulator 42. A drive motor, for example, a stepping motor, is built in the connecting shaft portion of the drive side manipulator 41 and configured to drive each joint arm at a predetermined angle, and the control device 5 is connected to the drive side manipulator 41. Therefore, when the driving side manipulator 41 is moved to a predetermined three-dimensional position by the control device 5, the laser head 6 of the driven manipulator 42 is also moved to the same position.

The control device 5 is configured by a computer, for example, and includes a control CPU 51, a display 52, and an input device (such as a mouse) 53. The control CPU 51 and the driver circuit of the drive side manipulator 41 are connected. The control CPU 51 incorporates a program for controlling the position of the drive side manipulator 41, and is configured to control the three-dimensional position of the laser head 6 according to the program.
This control program is configured as follows, for example. The control CPU 51 stores the original shape of the mold 1 as, for example, CAD data. The program displays a mold shape (hereinafter referred to as an original model shape) on the display 52, and displays a pointer on the model shape with the irradiation light of the laser head as a cleaning point. At the same time, the position of the cleaning point can be changed by operating the mouse, for example, and at the same time, the scanning width can be changed according to the shape of the mold by changing the amplitude width of the galvanometer mirror.

  Therefore, the control device 5 controls the drive side manipulator 41 so as to synchronize the three-dimensional position of the laser head 6 in accordance with the cleaning point displayed on the display 52. Thus, the operator can move the position of the laser head 6 according to the original model shape taught on the display 52. At the same time, the control device 5 calculates the irradiation distance between the laser head 6 and the mold from, for example, data of the original model shape.

  In the illustrated apparatus, the laser head 6 is provided with a coaxial observation monitor (not shown) in order to facilitate the control of the control device 5. This monitor is configured as follows, for example. As described above, the laser head 6 incorporates a long focal lens (cylindrical lens; not shown) and irradiates the mold 1 with laser light. At this time, the laser beam irradiated on the mold from the back side of the lens can be observed. By observing the plume emitted from the mold residue by this, the operator controls the position of the laser head while observing whether the laser beam is irradiated to the appropriate groove pattern position or whether the residue is reliably removed 5 can be controlled.

  Next, a cleaning method according to the present invention will be described. A partial residue melting step of irradiating a short pulse CO2 laser beam of a filament along the tire pattern shape 1a formed on the mold 1 and the partial residue melting step. Of the tire pattern in the tread direction of the tire pattern, the circumferential scan cleaning in which the width direction scan cleaning is scanned in the circumferential direction of the tire pattern, and the unevenness of the tire pattern in the width direction scan cleaning and the circumferential direction cleaning. Clean the mold surface by running along the shape.

The shape of a vulcanization mold for rubber tires is shown as one form of an object to be cleaned. Explanatory drawing of the whole structure of the washing | cleaning apparatus of this invention. FIG. 3 is a detailed explanatory diagram of a laser head unit in the apparatus of FIG. 2. FIG. 3 is a detailed explanatory view of a multi-joint arm portion in the apparatus of FIG. FIG. 3 is a waveform model diagram of laser light in the apparatus of FIG. 2. Structure explanatory drawing of the conventional laser cleaning apparatus.

Explanation of symbols

1 Mold 1a Tread pattern (groove pattern)
2 Work table 3 Laser oscillator (Oscillator body)
4 Manipulator 5 Control device (computer)
6 Laser head 41 Drive side manipulator 42 Driven side manipulator 42a Articulated arm 43a, 43b, 43c Connecting shaft 51 Control CPU
52 Display 53 Mouse device A Cleaning device

Claims (8)

A workpiece mounting table on which an object to be cleaned is mounted;
A manipulator having an articulated arm with at least two nodes disposed above the workpiece mounting table;
A laser head disposed at the tip of the manipulator;
A laser oscillator for supplying laser light to the laser head;
An optical element provided on the laser bed for irradiating the object to be cleaned with laser light;
And a control means for moving the manipulator along the shape of the object to be cleaned.
A cleaning apparatus, wherein the laser oscillator emits a CO2 laser or other short pulse laser light, and the manipulator moves the laser head along an uneven shape formed on an object to be cleaned. The optical element has a cylindrical lens and / or a polygon mirror or a galvanometer mirror,
The cleaning apparatus according to claim 1, wherein the laser head irradiates the object to be cleaned as a linear beam homogenized with the laser beam from the laser oscillator. The object to be cleaned is composed of a mold for vulcanization molding of a rubber tire,
The laser head emits line light in the tread direction to the tire pattern formed on the mold,
3. The tire mold according to claim 1, wherein the manipulator is controlled to move the laser head in the tread direction and the circumferential direction of the tire pattern with respect to the tire pattern of the mold. 4. Cleaning device. The manipulator is composed of at least two-joint multi-joint arm members having the laser head at the distal end and the laser oscillator at the proximal end, and a drive manipulator coupled to the multi-joint arm member.
The cleaning apparatus according to any one of claims 1 to 3, wherein the control means is configured by a computer that three-dimensionally controls the drive manipulator. The object to be cleaned is composed of a mold for vulcanization molding of a rubber tire,
5. The computer according to claim 4, wherein the computer includes cad and other reference shape data relating to the original shape of the mold, and performs position control of the laser head and irradiation light shape control based on the reference shape data. The cleaning apparatus according to 1. The object to be cleaned is composed of a mold for vulcanization molding of a rubber tire,
The computer comprises CAD and other reference shape data related to the original shape of the mold,
5. The cleaning apparatus according to claim 4, wherein the manipulator controls the position of the laser head based on the reference shape data and a signal from an operation means for correcting the position of the laser head. A cleaning method for removing residues adhering to a mold for vulcanizing a rubber tire,
A partial residue melting step of irradiating a short pulse CO2 laser beam of a filament along the tire pattern shape formed on the mold;
Width direction scanning cleaning that scans the partial residue dissolving step in the tread direction of the tire pattern;
Circumferential scanning cleaning for scanning the width direction scanning cleaning in the circumferential direction of the tire pattern;
A tire mold cleaning method, wherein the mold surface is subjected to surface cleaning by performing the width direction scanning cleaning and the circumferential direction cleaning along an uneven shape of a tire pattern. The tire mold cleaning method according to claim 7, wherein the width direction scanning cleaning and the circumferential direction scanning cleaning are automatically performed based on the original shape data of the mold.

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