KR20210151340A - Glass tube cutting method and apparatus using gas torch and laser - Google Patents

Abstract

The present invention is a method for cutting a glass tube by using a preheating device and a laser and, more specifically, to a glass tube cutting method and a device thereof. The glass tube cutting method comprises the following steps of: preheating a portion near a cut schedule line of a glass tube to a softening point of the glass tube with a gas torch to cut the glass tube without cracks, chipping and contamination; and cutting the glass tube by using a CO_2 laser beam having a wavelength which is well absorbed onto glass along the preheated cut schedule line of the glass tube.

Description

Glass tube cutting method and apparatus using gas torch and laser}

The present invention is a method and apparatus for cutting a glass tube using a preheating device and a laser. Specifically, in order to cut the glass tube without cracks, chipping and contamination, a gas torch near the cut line of the glass tube to the softening point of the glass tube. And, it relates to a glass tube cutting method and apparatus for cutting a glass tube using _{a CO 2} laser beam having a wavelength that is well absorbed by the glass along the cut line of the preheated glass tube.

Glass produced with silica sand as the main component and as sub-materials such as borax, limestone, and sodium carbonate is a semi-solid (amorphous) material whose melting point is not specified. Post-processing such as polishing is required.

For mechanical cutting, diamond cutters are mainly used, but microcracks and chips cannot be avoided at the same time.

Glass cut by this mechanical cutting method is brittle even with small bending pressure due to microcracks and sharp edges.

In addition, in the conventional cutting process, secondary contamination of the material is generated while using a liquid including water.

The development of processing technology such as drilling and cutting of glass using high-power laser light has a long history since the development of laser, and as new laser technology is developed, glass processing technology using it is also in progress.

Glass cutting methods using a laser can be broadly divided into:

(1) A method of rapid cooling after thermal shock with a laser (Ref....);

(2) A method of cutting without cracks on the surface by forming multiple focal points inside the glass with a laser (Ref.... also called stealth cutting)

(3) There are various methods, such as a method of evaporating and cutting the actual glass surface with a laser, and each has many advantages and disadvantages.

_{If the CO 2} laser is focused and irradiated on the glass at room temperature, cutting is possible due to the melting and evaporation of the glass, but cracks may occur due to residual stress due to excessive thermal gradient in the base material part and the part near the processing, and the cutting surface becomes rough. There is a problem.

For reference, the internet site: https: // www.or-laser.com/en/facts-laser-cutting/laser-cutting-glass / and https: // www.rofin.com/en/applications/laser-cutting Prior art can be found in /glass/, etc.

Republic of Korea Patent No. 10-1344373 Republic of Korea Patent No. 10-1704463

The problem to be solved by the present invention is that if a CO ₂ laser is focused and irradiated on glass at room temperature, it can be cut by melting and evaporation of the glass, but cracks may occur due to residual stress due to excessive thermal gradient between the base metal part and the processing part. In order to solve the problem that the cut surface is rough, the glass tube to be cut is rotated and preheated with a gas torch to smooth the cut area by cutting with a laser.

Another problem to be solved by the present invention is that the glass is easy to melt and evaporate by focusing _{the CO 2 laser beam on the surface of the glass tube by using the excellent absorption of the CO 2} laser (wavelength 9um to 10um band). This is to make the cut area smooth.

Another problem to be solved by the present invention is:

(1) There should be no cracks or chipping on the cut surface (same condition as the smooth surface and high breaking strength)

(2) There should be no foreign substances on the cut surface.

(3) Residual stress on the cut surface should be low below the critical point, and if the residual stress is higher than the critical point, no cracks will occur afterward.

(4) High productivity (high-speed cutting)

(5) Good economic feasibility (costs of production facilities and maintenance costs, etc.) are included.

The present invention is an invention that has solved all of the above technical problems.

A means for solving the problems of the present invention is a method of cutting a glass tube, the step of preheating to near the softening point of the glass tube with a gas torch near the cut line of the glass tube in order to cut the glass tube without cracks, chipping and contamination; Cutting the preheated glass tube An object of the present invention is to provide a glass tube cutting method for cutting a glass tube by using _{a CO 2} laser beam having a wavelength that is well absorbed by the glass along a predetermined line.

Another solution to the problem of the present invention is to uniformly preheat the glass tube while rotating the glass tube a number of times using a motor while holding it with a soft gripper so that the glass is not damaged in order to uniformly preheat the glass tube. To provide a glass tube cutting method for cutting while rotating.

A means of solving another problem of the present invention is to preheat in the range of 200° C. up and down based on the softening point, _{and use a CO 2} laser having a wavelength that is well absorbed by glass, but by using a pulsed laser that can control the duty ratio. An object of the present invention is to provide a method of cutting a glass tube that can reduce a separate cleaning and processing process after cutting.

As a means of solving another problem of the present invention, the preheating range of the glass tube is 5 to 15 times the thickness of the material in each of the upper and lower or left and right sides based on the cut line, and prevents contaminants from adhering to the inner wall of the glass tube during cutting To provide a glass tube cutting method for cutting while blowing heated clean air into the glass tube with a pump.

Another solution to the problem of the present invention is to arrange two glass tube cutting modules adjacent to each other _{and alternately operate a gas torch for preheating and a CO 2} laser for cutting with a switch to increase productivity. is to provide

A means for solving another problem of the present invention is a device for cutting a glass tube, a gas torch for preheating the vicinity of the cut line of the glass tube to near the softening point in order to cut the glass tube without cracks, chipping and contamination, and the preheated glass tube It is to provide a glass tube cutting device for cutting a glass tube using _{a CO 2} laser having a wavelength that is well absorbed by the glass along the cutting line.

In the present invention, after preheating a glass tube to near the softening point with a gas torch while rotating with a rotating motor, a CO ₂ laser beam having a wavelength with excellent absorption on the glass is focused and irradiated with a condensing lens. There is an advantageous effect of preventing cracks that may occur due to residual stress and smoothing the cut surface.

In addition, since the present invention cuts after preheating to near the softening point of the glass tube, (1) it is possible to prevent cracks or chipping on the cut surface, (2) it is possible to prevent adhesion of foreign substances to the cut surface, and (3) the residual stress on the cut surface is the critical point As low as less than, (4) other additional processes including cleaning after cutting can be reduced, there is an increased effect of high productivity.

Another effect of the present invention is to arrange two glass tube cutting modules adjacent to each other and _{to alternately operate a gas torch for preheating and a CO 2} laser for cutting with a switch to reduce the production cost when configured as a dual head that increases productivity. There is a possible synergistic effect.

1 shows a schematic diagram of a glass tube cutting device using a gas torch and a laser according to the present invention.
Figure 2 shows the shape of the dual head for cutting the glass tube shown based on the schematic diagram of Figure 1.
3 is a cross-section of a glass tube cut with only a laser.
4 shows a cross section of a glass tube cut using a laser and a gas torch according to the present invention.

Let's look at the specific content for carrying out the present invention.

The present invention comprises the steps of preheating a glass tube to the softening point of the glass tube with a gas torch near the cut line of the glass tube in order to cut the glass tube without cracks, chipping and contamination; A glass tube cutting method and apparatus for cutting a glass tube using a CO _{2 laser beam.} A detailed embodiment according to the present invention will be described.

<Example>

A detailed embodiment according to the present invention will be described with reference to the drawings.

1 shows a schematic diagram for explaining a method and apparatus for cutting a glass tube using a gas torch and a laser according to the present invention.

Figure 2 shows the shape of the dual head for cutting the glass tube shown based on the schematic diagram of Figure 1.

3 is a cross-section of a glass tube cut with only a laser, and has a rough surface.

4 shows a cross section of a glass tube cut using a laser and a gas torch according to the present invention, and the cut surface is smooth.

The development of processing technology such as drilling and cutting of glass using high-power laser light has a long history since the development of laser, and as new laser technology is developed, glass processing technology using it is also in progress.

The glass cutting method using a laser is largely (a) a method of rapid cooling after thermal shock with a laser, (b) a method of forming multiple focal points inside the glass with a laser and cutting without cracks on the surface (also called stealth cutting) (c) Actual There are various methods such as evaporating and cutting the glass surface with a laser, and each has many advantages and disadvantages.

The present invention relates to a cutting method in which a glass tube in the form of a pipe is cut by a combination of a laser and a gas torch (gas burner), so that the cut surface is smooth, there is no chip generation, there is no contamination of the glass, and cleaning is not required.

Glass is excellent energy absorption in the wavelength band (9um ~ 10um) of the CO ₂ laser, and the thermal conductivity because it has a bad features when focused (focusing) with a lens the CO ₂ laser beam is easy to melt and the evaporation process of the glass .

The problem in cutting glass by focusing the CO ₂ laser beam with a condenser lens is that the vicinity of the laser focus on the glass surface evaporates and scatters in gaseous form. There is a problem of generating contamination.

In addition, microcracks may be generated around the cut surface due to excessive thermal shock, or excessive residual stress may remain and cracks may occur after a certain period of time has elapsed.

Looking at the desired results from the process of cutting glass tubes using a CO _{2 laser:}

(1) There should be no cracks or chipping on the cut surface (same condition as the smooth surface and high breaking strength);

(2) There will be no foreign substances on the cut surface,

(3) Residual stress on the cut surface should be low below the critical point.

(4) High productivity (high-speed cutting)

(5) It should be economical (cost of production facilities and maintenance cost, etc.), etc.

The present invention has solved all of the above technical problems (1) to (5).

_{If the CO 2} laser is focused and irradiated on the glass at room temperature, it can be cut due to the melting and evaporation of the glass. There is this.

Glass is an amorphous material that does not have a specific melting point, and when heated near its softening point, it has the property of a highly viscous liquid.

The glass tube cutting apparatus and method according to the present invention have no cracks or chipping, no foreign substances, no post-cracking, and productivity when cutting a glass tube using a _{pulsed CO 2 laser and a high-temperature gas torch sequentially and in parallel.} It has excellent cutting properties such as high point.

Looking at the technical configuration of a more specific method for implementing the excellent characteristics as described above;

(1) Concentrically hold the glass tube to be cut with a gripper and rotate it using a rotating motor. A considerable section (5 to 15 times the thickness of the material in the top and bottom) is cut around the planned line to be cut (up and down) until it reaches a predetermined temperature near the softening point (about 600℃ in the case of soda ash glass) around the line to be cut (cutting sheet) and preheating with a gas torch.

(2) _{condensing the CO 2} laser beam with a lens (focal diameter of several 10 μm to several 100 μm) to cut the glass tube.

When preheating with a gas torch, it is desirable to preheat evenly along the cut line while rotating the glass tube several times in order to make the temperature distribution as homogeneous as possible.

When the temperature distribution of the cut area is homogeneous, there is an advantage that the cut surface is smooth after cutting and no secondary operation is required.

In _{the process of cutting with a CO 2} laser, it is preferable to cut while rotating the glass tube.

In this case, it is possible to obtain an elevated effect of a smooth cut surface and uniform quality.

The process of rotating several wheels when preheating with a gas torch is a natural process for a more homogeneous temperature gradient, but cutting by rotating a glass tube several turns during laser cutting also has another effect.

There is also the effect of minimizing the inflow of cutting by-products into the glass tube by minimizing the volume of the glass to be cut during the last rotation of the laser cutting wheel.

Pulsed CO ₂ laser is a pulsed laser with a higher peak power than a CW (continuous wave) laser with a constant output intensity. The duty cycle of the pulsed laser beam is controlled Therefore, it is preferable to use it by adjusting the average output.

In the glass tube cutting process, the CW-type CO ₂ laser has a very good laser light absorption rate of the glass, so the temperature of the laser light focus becomes too high and a lot of fine glass dust is generated. have.

The pulsed CO ₂ laser suppresses the generation of fine glass dust by appropriately adjusting the frequency and duty cycle, and the dust with a moderately large size does not stick to the glass surface around the cutting line, but is installed adjacent to the cutting part. (not shown) can be configured to be absorbed well.

_{For glass tube cutting, it is preferable to use a pulsed CO 2} laser rather than a continuous wave (CW) laser by appropriately adjusting the frequency and duty cycle for the same reason as described above.

The glass tube cutting according to the present invention _{is preferably a pulsed CO 2} laser, but various types of lasers may be used.

As described above, in the process of melting and evaporating a glass tube using a laser, cutting by-products (glass powder, etc.) are inevitably generated. When the area around the cutting line is sufficiently preheated to near the softening point, these by-products are not attached to the glass tube (raw material) again. It can be configured to be well sucked into the fume inlet (intake device).

The laser cutting method according to the present invention is preheated by applying considerable heat to the glass tube (material) near the cutting line. After rotating several wheels and digging a groove, at the end, when the glass becomes thin to some extent, the penetrating cutting process is performed. do.

In this case, since the cut part is cut with laser heating added to the preheated temperature up to the softening point, there is an advantageous effect of having a smooth outer surface without sharp edges on the inner surface as well as the outer surface.

In this case, there is no need for a cleaning process to remove contaminants or a process for smoothing the cut surface.

A small amount of cutting by-products flows into the inside of the glass tube through the gap during the last rotation of the cutting line, but it is not reattached due to the high enough temperature around the cutting line.

By-products discharged to the outside are sucked in by the suction device to prevent air pollution.

In the present invention, in the process of laser cutting, the intensity of the gas torch should be reduced or removed (moving or turning off the flame).

In the case of continuously heating the cut surface of the glass tube with a gas torch, if the heating continues, the softening point is naturally exceeded, and a phenomenon in which the cut surface is re-fused may occur.

Since the main purpose of the gas torch is to preheat the glass tube to the softening point, it is possible to use various types of gas torches. /oxygen torch, acetylene/oxygen torch, hydrogen/oxygen torch, etc.) are effective, but it is preferable to select it in consideration of cost and productivity.

The spatial range of preheating the glass tube is preferably 5 to 15 times the thickness of the glass tube (material) in the upper and lower (or left and right) directions of the cut line. , If you preheat a larger area than this, energy is wasted heavily and it takes a long time to cool down.

The temperature range for preheating is about 200°C above and below the softening point of the glass (600°C in the case of soda ash glass).

Conversely, if it is preheated to too high a temperature, the shape of the cut surface may be deformed along with wasted energy.

It is effective for the cutting process to alternately use a gas torch for preheating and a CO ₂ laser for cutting, and productivity can be increased by supplying glass tubes in two rows and designing and manufacturing to alternately use the _{gas torch and CO 2 laser sequentially.}

Based on the description described above, the technical configuration of the glass tube cutting method according to the present invention will be summarized.

One embodiment according to the present invention is a method for cutting a glass tube, in order to cut the glass tube without cracks, chipping and contamination, preheating to near the softening point of the glass tube with a gas torch near the cut line of the glass tube and absorption into the glass A glass tube cutting method of cutting a glass tube by condensing _{a CO 2} laser beam having a wavelength to be condensed with a condenser lens.

Another embodiment of the present invention is to preheat the glass tube by holding it softly with a gripper so as not to damage the glass in order to uniformly preheat the glass tube and rotating the glass tube several times using a rotation motor, and to preheat the glass tube several times for smooth cutting during cutting. Cut while rotating.

Another embodiment of the present invention is preheated in the range of 200 ℃ up and down based on the softening point.

_{Another embodiment of the present invention uses a CO 2} laser having a wavelength that is well absorbed by glass, _{but a pulsed CO 2} laser capable of adjusting a duty ratio.

In another embodiment of the present invention, the preheating range of the glass tube is preferably preheated in the range of 5 to 15 times the thickness of the glass tube (material) in the upper and lower or left and right sides based on the line to be cut.

Another embodiment of the present invention cuts while blowing clean air heated into the glass tube with a pump in order to prevent contaminants from adhering to the inner wall of the glass tube during cutting.

Another embodiment of the present invention arranges two glass tube cutting modules adjacent to each other, _{and alternately operates a gas torch for preheating and a CO 2} laser for cutting with a switch to increase productivity. can be used to cut

The dual head is shown in FIG. 2, and as shown in FIG. 2, two lasers and a gas torch are configured as one set to increase productivity and reduce the installation space of the device.

Another embodiment of the present invention includes the step of sucking the by-products with an intake device installed adjacent to the cutting line in order to prevent air pollution by the cutting by-products generated when the glass tube is cut.

Look at the glass tube cutting device according to the present invention.

The glass tube to be cut (11 in Fig. 1) is held in the upper rotating gripper (13 in Fig. 1) through which heated air (12 in Fig. 1) passes (soft gripping), and the concentric glass tube is idling (non-powered). , idling) Set the glass cutting line (15 in Fig. 1) at an appropriate position below the gripper (14 in Fig. 1) and rotate it using a rotary motor (22 in Fig. 1).

The configuration of rotating the glass tube with the rotation motor can be connected to the rotation motor (22 in FIG. 1) using a variety of conventional means including a belt to rotate the glass tube with the rotational force of the rotation motor.

After uniformly heating an area at a predetermined distance (5 times to 15 times the thickness of the material) before and after the cutting line to the vicinity of the softening point of the glass (up and down 200 ℃) using a gas torch (16 in Fig. 1), a pulsed CO ₂ laser ( 17 in Fig. 1) and a condensing lens (18 in Fig. 1) are used to collect the light, rotate the glass tube several times, and cut it little by little as if digging a groove.

The cut glass tube falls to the lower holder (20 in FIG. 1) by gravity along the lower guide (19 in FIG. 1) and moves to the next process (21 in FIG. 1) for cooling.

The lower part of the cut base material glass tube and the upper part of the cut glass tube are finished with sharp edges by preheating the gas torch and heating the laser.

In the last part where the glass tube is cut, a small amount of glass, depending on the laser focal width, remains, leaving fine protrusions on both sides.

After the glass tube cutting operation according to the present invention, the cutting is done smoothly enough that there is no need for a separate polishing operation.

Another embodiment according to the present invention is an apparatus for cutting a glass tube, a gas torch for preheating the vicinity of the cut line of the glass tube to near the softening point in order to cut the glass tube without cracks, chipping and contamination, and cutting of the preheated glass tube A glass tube is cut using _{a CO 2} laser with a wavelength that is well absorbed by the glass along a predetermined line.

The present invention is a method and apparatus for cutting a glass tube using a preheating device and a laser. Specifically, in order to cut the glass tube without cracks, chipping and contamination, a gas torch near the cut line of the glass tube to the softening point of the glass tube. _{And, by providing a glass tube cutting method and apparatus for cutting a glass tube using a CO 2} laser beam with a wavelength that is well absorbed by the glass along the cut line of the preheated glass tube, it is possible to reduce the addition of processing and cleaning processes after cutting Therefore, the potential for industrial application is very high.

11; glass tube 12; heated air
13; upper rotating gripper 14; idling gripper
15; glass cut line 16; gas torch
17; laser 18; condensing lens
19; lower guide 20; lower holder
21; next process 22; rotary motor
31; gas 32; gas torch 1
33; gas torch 2 34; glass tube 1
35; glass tube 2 36; laser head 1
37; laser head 2 38; Glass tube cutting module 1
39; Glass Tube Cutting Module 2

Claims (12)

A method for cutting a glass tube, the method comprising:
Preheating the glass tube to a softening point of the glass tube with a gas torch in the vicinity of the cut line of the glass tube to cut the glass tube without cracks, chipping and contamination; and
A glass tube cutting method in which a glass tube is cut using _{a CO 2} laser beam having a wavelength that is well absorbed by the glass along the cut line of the preheated glass tube. The method according to claim 1,
In order to preheat the glass tube uniformly, hold it with a soft gripper so as not to damage the glass and rotate the glass tube several times using a motor to preheat.
Glass tube cutting method that cuts while rotating multiple times for smooth cutting even when cutting. The method according to claim 1,
Preheating is a glass tube cutting method, characterized in that it is made in the range of 200 ℃ up and down based on the softening point. 4. The method according to any one of claims 1 to 3,
_{A method of cutting a glass tube using a CO 2} laser having a wavelength that is well absorbed by glass, but using a pulsed laser with an adjustable duty ratio. 4. The method according to any one of claims 1 to 3,
Glass tube cutting method, characterized in that the preheating range of the glass tube is 5 to 15 times the thickness of the material in each of the upper and lower or left and right sides based on the line to be cut. 4. The method according to any one of claims 1 to 3,
A method of cutting a glass tube, characterized in that the cutting is performed while blowing heated clean air into the glass tube with a pump in order to prevent contaminants from adhering to the inner wall of the glass tube during cutting. 4. The method according to any one of claims 1 to 3,
A method for cutting glass tube, characterized in that it consists of a dual head that increases productivity by arranging two glass tube cutting modules adjacent to _{each other, and alternately operating a gas torch for preheating and a CO 2 laser for cutting with a switch.} 4. The method according to any one of claims 1 to 3,
The method of cutting a glass tube further comprising the step of sucking the by-product through an intake device installed adjacent to the cutting line in order to prevent air pollution by the cutting by-product generated during the cutting of the glass tube. In the apparatus for cutting a glass tube,
a gas torch for preheating the vicinity of the cut line of the glass tube to near the softening point in order to cut the glass tube without cracks, chipping and contamination; and
A glass tube cutting device that cuts a glass tube by using _{a CO 2} laser with a wavelength that is well absorbed by the glass along the cut line of the preheated glass tube. 10. The method of claim 9,
In order to preheat the glass tube uniformly, hold it with a soft gripper so as not to damage the glass and rotate the glass tube several times using a motor to preheat.
A glass tube cutting device that cuts while rotating multiple times for smooth cutting during cutting. 12. The method according to claim 9 or 11,
Glass tube cutting device, characterized in that it further comprises an air injection pump to blow heated clean air into the glass tube to prevent contaminants from adhering to the inner wall of the glass tube during cutting. 12. The method according to claim 9 or 11,
A glass tube cutting device, characterized in that it consists of a dual head that increases productivity by arranging two glass tube cutting modules adjacent to each other _{and alternately operating a gas torch for preheating and a CO 2 laser for cutting with a switch.}

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