Laser processing apparatus

Abstract

To detect the temperature rise of a plurality of protective glasses by a small number of temperature sensors in a laser beam machining apparatus.SOLUTION: The laser machining device 1 includes the focus lens 20 that condenses the laser light L, the first protective glass 30 that is disposed on the emission-side Z1 with respect to the focus lens 20, the second protective glass 40 that is disposed between the focus lens 20 and the first protective glass 30, the first holder 50 that holds the first protective glass 30, the second holder 60 that holds the second protective glass 40, and the temperature sensors 80 that are held by one of the first holder 50 and the second holder 60. The first holder 50 and the second holder 60 are formed separately from each other and are in contact with each other so that the heat Q is conducted.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a laser processing apparatus. [Background technology]

[0002] The laser processing device disclosed in Patent Document 1 includes a focus lens that focuses laser light, a first protective glass that is arranged closer to the emission side than the focus lens, a second protective glass that is arranged between the focus lens and the first protective glass, and a temperature sensor that is arranged in contact with the first protective glass and detects the temperature of the first protective glass. The laser light emitted from the laser processing device is irradiated onto a workpiece. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2024-000856 Summary of the Invention [Problem to be solved by the invention]

[0004] In the laser processing device disclosed in Patent Document 1, the first protective glass is disposed on the emission side (closer to the workpiece) than the second protective glass. The temperature of the first protective glass usually rises earlier than that of the second protective glass due to the influence of debris from the workpiece adhering to the first protective glass.

[0005] In this case, the temperature of the first protective glass may be detected by a temperature sensor disposed in contact with the first protective glass. For example, if the temperature of the first protective glass detected by the temperature sensor rises above a threshold value, the laser processing device may be stopped to prevent damage to the first protective glass.

[0006] However, although it is rare, there are cases where the temperatures of the first and second protective glasses rise at the same time, or where the temperature of the second protective glass rises before the temperature of the first protective glass.

[0007] In this case, the temperature sensor placed in contact with the first protective glass cannot detect the temperature of the second protective glass, and the temperature rise of the second protective glass may be left undetected, which may result in damage to the second protective glass.

[0008] It is also possible to provide a new temperature sensor in contact with the second protective glass in addition to the temperature sensor in contact with the first protective glass. However, increasing the number of temperature sensors would complicate the configuration of the laser processing device and increase the manufacturing costs of the laser processing device.

[0009] An object of the present disclosure is to detect temperature increases of multiple protective glasses in a laser processing device using a small number of temperature sensors. [Means for solving the problem]

[0010] The laser processing apparatus according to the present disclosure comprises a focus lens that focuses laser light, a first protective glass that is positioned on the output side of the focus lens, a second protective glass that is positioned between the focus lens and the first protective glass, a first holder that holds the first protective glass, a second holder that holds the second protective glass, and a temperature sensor held in one of the first holder and the second holder, wherein the first holder and the second holder are configured as separate bodies and are in contact with each other so that heat is conducted. [Effects of the Invention]

[0011] According to the present disclosure, in a laser processing device, temperature increases of a plurality of protective glasses can be detected using a small number of temperature sensors. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 shows a laser processing device. [Figure 2]FIG. 2 shows a schematic diagram of the internal structure of the laser processing head of the laser processing device. [Figure 3] FIG. 3 shows in detail the internal structure of the laser processing head of the laser processing device. [Figure 4] FIG. 4 shows the temperature rise per unit time detected by the temperature sensor. [Figure 5] FIG. 5 shows the relationship between the temperature rise per unit time and the stop temperature. [Figure 6] FIG. 6 shows the control flow of the laser processing device. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0014] (Laser processing equipment) 1 shows a laser processing apparatus 1. The laser processing apparatus 1 processes a workpiece W with a laser beam L. The laser processing apparatus 1 includes a laser oscillator 2, a transmission fiber 3, a laser processing head 4, a robot 5, and a controller 6.

[0015] The laser oscillator 2 oscillates and emits laser light L. For example, a solid-state laser light source, a gas laser light source, or a fiber laser light source can be used as the laser oscillator 2. The laser oscillator 2 may also be a semiconductor laser light source that directly uses light emitted from a semiconductor laser, or a semiconductor laser array that includes multiple laser light emitters.

[0016] The input end of the transmission fiber 3 is connected to the laser oscillator 2. The output end of the transmission fiber 3 is connected to the laser processing head 4. The laser light L output from the laser oscillator 2 is transmitted to the laser processing head 4 via the transmission fiber 3.

[0017] The laser processing head 4 emits the laser light L transmitted from the transmission fiber 3. The laser light L emitted from the laser processing head 4 is irradiated onto the workpiece W. Details of the laser processing head 4 will be described later.

[0018] The robot 5 holds the laser processing head 4. The robot 5 moves the laser processing head 4 to change the emission position and focal position of the laser light L relative to the workpiece W.

[0019] The controller 6 is composed of, for example, a microcomputer, a memory, and a program. The controller 6 is connected to the laser oscillator 2, the laser processing head 4, and the robot 5 by wire or wirelessly. The controller 6 controls the movement of the laser processing head 4 by the robot 5, the output of the laser light L by the laser oscillator 2, etc. Details of the controller 6 will be described later.

[0020] (Laser processing head) 2 shows a schematic diagram of the internal structure of the laser processing head 4 of the laser processing apparatus 1. The laser processing head 4 of the laser processing apparatus 1 includes a collimation lens 10, a focus lens 20, a first protective glass 30, a second protective glass 40, a first holder 50, a second holder 60, an interposing member 70, and a temperature sensor 80. These components of the laser processing head 4 are housed inside a housing 4a (see also FIG. 3).

[0021] In the following description, the side of the laser processing head 4 in the direction of travel of the laser light L is referred to as the emission side Z1, and the side of the laser processing head 4 opposite to the side in the direction of travel of the laser light L is referred to as the incidence side Z2. The emission side Z1 is also the side closer to the workpiece W. The incidence side Z2 is also the side farther from the workpiece W. In this example, the direction of travel of the laser light L in the laser processing head 4 is vertical, with the emission side Z1 being the lower side and the incidence side Z2 being the upper side.

[0022] The collimation lens 10 is disposed closer to the incident side Z2 than other components in the laser processing head 4. The collimation lens 10 collimates the laser light L introduced into the laser processing head 4 from the output end of the transmission fiber 3. The collimation lens 10 is made of glass.

[0023] The focus lens 20 is disposed closer to the output side Z1 than the collimation lens 10. The focus lens 20 collects the laser light L that has been collimated by the collimation lens 10. The laser light L has a high energy density due to being collected by the focus lens 20. The focus lens 20 is made of glass.

[0024] The first protective glass 30 is arranged closer to the emission side Z1 than the focus lens 20. The second protective glass 40 is arranged between the focus lens 20 and the first protective glass 30. The first protective glass 30 is arranged closer to the emission side Z1 (the side closer to the workpiece W) than the other lenses and other glasses (including the second protective glass 40) in the laser processing head 4. The second protective glass 40 is arranged closer to the emission side Z1 than the focus lens 20 and closer to the incidence side Z2 than the first protective glass 30. The first protective glass 30 is made of glass. The second protective glass 40 is made of glass.

[0025] The first protective glass 30 and the second protective glass 40 protect the focus lens 20 so that scattered matter (fumes, spatters, etc.) generated when the workpiece W is processed with the laser light L does not adhere to the focus lens 20. The first protective glass 30 and the second protective glass 40 also protect the collimation lens 10.

[0026] 3 shows in detail the internal structure of the laser processing head 4 of the laser processing apparatus 1. The first holder 50 holds the first protective glass 30. More specifically, the first holder 50 is substantially cylindrical, and holds the first protective glass 30 on its inner peripheral wall. The first holder 50 is made of metal.

[0027] The second holder 60 holds the second protection glass 40. More specifically, the second holder 60 is substantially cylindrical, and its inner peripheral wall holds the second protection glass 40. The second holder 60 is made of metal.

[0028] The first holder 50 and the second holder 60 are configured as separate bodies. The first holder 50 is disposed closer to the emission side Z1 than the second holder 60. The second holder 60 is disposed closer to the incidence side Z2 than the first holder 50. The first holder 50 and the second holder 60 are not in direct contact with each other (there is a gap between them).

[0029] The intervening member 70 is interposed between the first holder 50 and the second holder 60. The intervening member 70 is disposed closer to the incident side Z2 than the first holder 50. The intervening member 70 is disposed closer to the exit side Z1 than the second holder 60. More specifically, the intervening member 70 is ring-shaped. More specifically, the intervening member 70 is housed in a small recess 51 provided on the inner periphery of the surface (top surface) of the substantially cylindrical first holder 50 on the incident side Z2. The intervening member 70 is made of metal.

[0030] The intervening member 70 is in contact with the first holder 50 on the emission side Z1. The intervening member 70 is in contact with the second holder 60 on the incidence side Z2. The first holder 50 and the second holder 60 are in indirect contact with each other via the intervening member 70. More specifically, the first holder 50 and the second holder 60 are in indirect contact with each other with the intervening member 70 sandwiched between them. The first holder 50 and the second holder 60 are in contact with each other via the intervening member 70 such that heat Q is conducted. The heat Q is conducted from the first holder 50 to the second holder 60 and from the second holder 60 to the first holder 50.

[0031] The temperature sensor 80 is held by the first holder 50. More specifically, the temperature sensor 80 is housed in a large recess 52 provided on the outer periphery of the surface (top surface) of the substantially cylindrical first holder 50 on the incident side Z2. The temperature sensor 80 is in contact with the first holder 50. The temperature sensor 80 is not in contact with the second holder 60. The temperature sensor 80 detects a temperature T. More specifically, the temperature sensor 80 directly detects the temperature T of the first holder 50. The temperature sensor 80 can also indirectly detect the temperature T of the first protective glass 30, the temperature T of the second protective glass 40, and the temperature T of the second holder 60.

[0032] The temperature sensor 80 is configured, for example, by a thermocouple or the like. Other configurations are also possible for the temperature sensor 80. The detection portion of the temperature sensor 80 is in contact with the first holder 50.

[0033] (Control mode of laser processing device) The control mode of the laser processing apparatus 1 will be described. Fig. 4 shows the temperature rise ΔT per unit time Δt related to the temperature T detected by the temperature sensor 80. In Fig. 4, the horizontal axis represents time t (unit: [s]) and the vertical axis represents temperature T (unit: [°C]).

[0034] The controller 6 is connected by wire or wirelessly to the temperature sensor 80 in the laser processing head 4. The temperature T detected by the temperature sensor 80 is input to the controller 6 at predetermined cycles (at predetermined time intervals). The controller 6 also obtains the time t using a built-in clock.

[0035] The controller 6 calculates the temperature rise ΔT per unit time Δt based on the obtained temperature T and time t. The unit time Δt can be set arbitrarily by the user. The unit time Δt is, for example, 1 [s]. The temperature rise ΔT per unit time Δt is also the temperature rise rate ΔT / Δt.

[0036] The controller 6 sets a stop temperature Ts. The stop temperature Ts is set to stop the laser processing apparatus 1. When the temperature T detected by the temperature sensor 80 reaches the stop temperature Ts, the laser processing apparatus 1 is stopped. Specifically, the laser oscillator 2 stops emitting the laser light L, and the robot 5 stops moving the laser processing head 4.

[0037] 5 shows the relationship between the temperature rise ΔT per unit time Δt and the stop temperature Ts. The controller 6 sets the stop temperature Ts for stopping the laser processing apparatus 1 based on the temperature rise ΔT per unit time Δt related to the temperature T detected by the temperature sensor 80.

[0038] The controller 6 sets the stop temperature Ts so that the stop temperature Ts increases as the temperature rise ΔT per unit time Δt increases. Conversely, the controller 6 sets the stop temperature Ts so that the stop temperature Ts decreases as the temperature rise ΔT per unit time Δt decreases.

[0039] The stop temperature Ts is initially set to an initial stop temperature Ts0. When the temperature rise ΔT per unit time Δt is smaller than a first threshold value ΔT1 (ΔT<ΔT1), the stop temperature Ts is maintained (set) at the initial stop temperature Ts0 (Ts=Ts0). When the temperature rise ΔT per unit time Δt is larger than the first threshold value ΔT1 and smaller than a second threshold value ΔT2 (ΔT1<ΔT<ΔT2), the stop temperature Ts is set to a first stop temperature Ts1 (larger than the initial stop temperature Ts0) (Ts=Ts1). When the temperature rise ΔT per unit time Δt is larger than a second threshold value ΔT2 and smaller than a third threshold value ΔT3 (ΔT2<ΔT<ΔT3), the stop temperature Ts is set to a second stop temperature Ts2 (larger than the first stop temperature Ts1) (Ts=Ts2). When the temperature rise ΔT per unit time Δt is greater than a third threshold ΔT3 (ΔT3<ΔT), the stop temperature Ts is set to a third stop temperature Ts3 (greater than the second stop temperature Ts2) (Ts=Ts3).

[0040] When the temperature rise ΔT per unit time Δt is exactly equal to the first threshold value ΔT1, the second threshold value ΔT2, or the third threshold value ΔT3 (ΔT=ΔT1, ΔT2, ΔT3), the stop temperature Ts is set to either the initial stop temperature Ts0, the first stop temperature Ts1, the second stop temperature Ts2, or the third stop temperature Ts3 based on a predetermined rule.

[0041] The initial stop temperature Ts0 corresponds to the case where neither the first protective glass 30 nor the second protective glass 40 increases in temperature. The first stop temperature Ts1 corresponds to the case where only the second protective glass 40 increases in temperature. The second stop temperature Ts2 corresponds to the case where only the first protective glass 30 increases in temperature. The third stop temperature Ts3 corresponds to the case where both the first protective glass 30 and the second protective glass 40 increase in temperature. Note that the above correspondence relationships merely represent rough trends and are by no means strict.

[0042] An upper limit may be set for the stop temperature Ts. In this case, once the stop temperature Ts reaches the upper limit, the stop temperature Ts remains constant at the upper limit even if the temperature rise ΔT increases beyond that limit.

[0043] (Control Flow) 6 shows a control flow of the laser processing apparatus 1. Starting from the start, in a first step S1, the controller 6 sets the stop temperature Ts to the initial stop temperature Ts0 (Ts=Ts0).

[0044] In the second step S2, the operation of the laser processing device 1 is started.

[0045] In a third step S3, the temperature sensor 80 starts detecting the temperature T. The temperature sensor 80 continues to detect the temperature T.

[0046] In a fourth step S4, the controller 6 calculates the temperature rise ΔT per unit time Δt.

[0047] In the fifth step S5, the stop temperature Ts is set based on the temperature rise ΔT per unit time Δt. Specifically, when the temperature rise ΔT is smaller than the first threshold value ΔT1 (ΔT < ΔT1), the stop temperature Ts is set (maintained) to the initial stop temperature Ts0 (Ts = Ts0); when the temperature rise ΔT is larger than the first threshold value ΔT1 and smaller than the second threshold value ΔT2 (ΔT1 < ΔT < ΔT2), the stop temperature Ts is set to the first stop temperature Ts1 (Ts = Ts1); when the temperature rise ΔT is larger than the second threshold value ΔT2 and smaller than the third threshold value ΔT3 (ΔT2 < ΔT < ΔT3), the stop temperature Ts is set to the second stop temperature Ts2 (Ts = Ts2); when the temperature rise ΔT is larger than the third threshold value ΔT3 (ΔT3 < ΔT), the stop temperature Ts is set to the third stop temperature Ts3 (Ts = Ts3).

[0048] In the sixth step S6, the temperature T is detected again by the temperature sensor 80.

[0049] In the seventh step S7, it is determined whether the temperature T detected by the temperature sensor 80 is larger than the stop temperature Ts (T > Ts?). When the temperature T is smaller than the stop temperature Ts (NO: T < Ts), the process returns to the third step S3. When the temperature T is larger than the stop temperature Ts (YES: T > Ts), the process proceeds to the eighth step S8.

[0050] In the eighth step S8, the operation of the laser processing apparatus 1 is stopped. And it reaches the end.

[0051] (Function and effect) In the laser processing apparatus 1, the first protective glass 30 is arranged on the emission side Z1 (the side closer to the workpiece W) than the second protective glass 40. The first protective glass 30 usually rises in temperature earlier than the second protective glass 40 due to the influence of adhesion of scattered materials from the workpiece W and the like.

[0052] Here, the temperature sensor 80 is held in the first holder 50 together with the first protective glass 30. The temperature sensor 80 directly detects the temperature T of the first holder 50. If the temperature of the first protective glass 30 rises, the temperature of the first holder 50 that holds the first protective glass 30 also rises. The temperature sensor 80 can indirectly detect the temperature rise of the first protective glass 30 by detecting the temperature T of the first holder 50.

[0053] However, although it is rare, the first protective glass 30 and the second protective glass 40 may rise in temperature at the same time, or the second protective glass 40 may rise in temperature before the first protective glass 30 does.

[0054] When the temperature of the second protective glass 40 rises, the temperature of the second holder 60 that holds the second protective glass 40 also rises. Heat Q is conducted from the second holder 60 (via the intervening member 70) to the first holder 50. Therefore, the temperature sensor 80 can indirectly detect the temperature rise of the second protective glass 40 by detecting the temperature T of the first holder 50.

[0055] A small number of temperature sensors 80 (one in this example) can detect both a temperature rise in the first protective glass 30 and a temperature rise in the second protective glass 40. Since there is no need to increase the number of temperature sensors 80, the configuration of the laser processing apparatus 1 does not become complicated, and the manufacturing cost of the laser processing apparatus 1 does not increase.

[0056] As described above, in the laser processing apparatus 1, a small number of temperature sensors 80 can detect temperature rises of a plurality of protective glasses (first protective glass 30 and second protective glass 40).

[0057] Since the temperature sensor 80 is held in the first holder 50 together with the first protective glass 30, it can preferentially detect the temperature rise of the first protective glass 30, which is more likely to rise in temperature than the second protective glass 40 (due to the influence of debris from the workpiece W, etc.), compared to when the temperature sensor 80 is held in the second holder 60 together with the second protective glass 40.

[0058] Even if the first holder 50 and the second holder 60 are not in direct contact, by bringing the first holder 50 and the second holder 60 into indirect contact via a metal intervening member 70, heat Q can be conducted from the second holder 60 to the first holder 50 via the intervening member 70.

[0059] Since the first holder 50 and the second holder 60 are both made of metal, the heat Q is easily conducted.

[0060] If the stop temperature Ts is set constant at a low value, overdetection may occur, resulting in the laser processing apparatus 1 being stopped, even if the temperatures of both the first protective glass 30 and the second protective glass 40 rise gradually at the same time (even if there is no risk of damage to either the first protective glass 30 or the second protective glass 40).

[0061] On the other hand, if the stop temperature Ts is set constant at a high value, even if the temperature of one of the first protective glass 30 and the second protective glass 40 rises significantly (even if there is a risk of damage to one of the first protective glass 30 and the second protective glass 40), a detection error may occur and the laser processing apparatus 1 may not be stopped.

[0062] By setting the stop temperature Ts for stopping the laser processing apparatus 1 based on the temperature rise ΔT per unit time Δt related to the temperature T detected by the temperature sensor 80, such overdetection and missed detection can be suppressed.

[0063] In particular, the stop temperature Ts is set so that the larger the temperature rise ΔT per unit time Δt, the larger the stop temperature Ts becomes, and conversely, the smaller the temperature rise ΔT per unit time Δt, the smaller the stop temperature Ts becomes.

[0064] This makes it possible to suppress overdetection when the temperature of both the first protective glass 30 and the second protective glass 40 increases gradually at the same time (when there is no risk of damage to either the first protective glass 30 or the second protective glass 40) by increasing the stop temperature Ts when the temperature rise ΔT is large.

[0065] Conversely, by reducing the stop temperature Ts when the temperature rise ΔT is small, it is possible to prevent missed detections when one of the first protective glass 30 and the second protective glass 40 experiences a large temperature rise (when there is a risk of damage to one of the first protective glass 30 and the second protective glass 40).

[0066] (Other embodiments) Although the present disclosure has been described above with reference to preferred embodiments, such description is not limiting, and it goes without saying that various modifications, substitutions, or combinations are possible.

[0067] In addition to the first protective glass 30 and the second protective glass 40, there may be a third protective glass.

[0068] Two or more intervening members 70 may be interposed between the first holder 50 and the second holder 60. The first holder 50 and the second holder 60 may be in direct contact with each other without an intervening member 70 therebetween.

[0069] The temperature sensor 80 may be held by the second holder 60. At this time, heat Q caused by the temperature rise of the first protective glass 30 is transferred from the first holder 50 to the second holder 60 and reaches the temperature sensor 80 (held by the second holder 60). The temperature sensor 80 may be held by either the first holder 50 or the second holder 60. There may be two or more temperature sensors 80.

[0070] The temperature sensor 80 may be arranged in contact with the first protective glass 30 or the second protective glass 40. In this case, the temperature sensor 80 can directly detect the temperature of the first protective glass 30 or the second protective glass 40.

[0071] The traveling direction of the laser light L is not limited to the vertical direction, but may be, for example, the horizontal direction. [Industrial Applicability]

[0072] The present disclosure is applicable to laser processing devices and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0073] 1. Laser processing equipment 2 Laser oscillator 3 Transmission Fiber 4 Laser processing head 4a Case 5. Robot 6 Controller 10 Collimation Lens 20 Focus Lens 30 First protective glass 40 Second protective glass 50 First Holder 51 Small recess 52 Large recess 60 Second Holder 70 Intervening member 80 Temperature Sensor L laser light double work Z1 Output side Z2 incident side Q Fever t time Δt unit time T temperature ΔT temperature rise ΔT1 First threshold ΔT2 Second threshold ΔT3 Third threshold Ts Stop temperature Ts0 Initial stop temperature Ts1 1st stop temperature Ts2 2nd stop temperature Ts3 3rd stop temperature

Claims

1. a focus lens that focuses the laser light; a first protective glass disposed on the output side of the focus lens; a second protective glass disposed between the focus lens and the first protective glass; a first holder that holds the first protective glass; a second holder that holds the second protective glass; a temperature sensor held by one of the first holder and the second holder, The first holder and the second holder are configured separately from each other, The laser processing apparatus, wherein the first holder and the second holder are in contact with each other so as to conduct heat.

2. The laser processing device according to claim 1 , wherein the temperature sensor is held by the first holder.

3. a metal interposition member interposed between the first holder and the second holder; 3. The laser processing device according to claim 1, wherein the first holder and the second holder are in indirect contact with each other via the intervening member.

4. the first holder is made of metal, The laser processing apparatus according to claim 1 or 2, wherein the second holder is made of metal.

5. Equipped with a controller, 3. The laser processing apparatus according to claim 1, wherein the controller sets a stop temperature for stopping the laser processing apparatus based on a temperature rise per unit time related to the temperature detected by the temperature sensor.

6. The laser processing device according to claim 5 , wherein the controller sets the stop temperature so that the stop temperature increases as the increased temperature increases.

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