Method for determining laser focus and laser focus confirmation system

Abstract

The invention discloses a method for determining a laser focus and a laser focus confirmation system. The method for determining the laser focus comprises the steps that a reference block is placed on a machining plane, and the reference block comprises a slope face; a linear laser scratch is formed on the slope surface through continuous light emitting, the head and the tail of the linear laser scratch form a height difference on the slope surface, a middle weld mark of the linear laser scratch is clear, and weld marks at the head and the tail are fuzzy; and confirming that the position point of the minimum width of the middle weld mark and the middle position of the head and tail weld marks is a laser focus. By means of the method for determining the laser focus, the position of the laser focus can be efficiently determined through one-time light emitting.

Description

Technical Field

[0001] The present application relates to the field of laser processing technology, and in particular to a method for determining a laser focus and a laser focus confirmation system. Background Art

[0002] Laser processing technology is increasingly used in the 3C, lithium battery, automobile, and hardware industries, gradually replacing traditional welding and machining to become an important processing technology. The laser is emitted from the processing head and usually has a certain focal depth. The focus positioning accuracy has a great influence on the laser processing effect. Inaccurate focus search will lead to poor processing results. Therefore, in the early stage of processing, it is necessary to accurately find and calibrate the laser focus position.

[0003] The current focus finding method is often carried out by multiple dotting or marking. In the actual operation process, the relative distance between the laser processing head and the processing surface and the position of the processing plane are usually adjusted. That is, each time the light is emitted, the Z axis of the processing head and the X axis (or Y axis) of the working surface need to be moved once. To complete a focus finding, it is necessary to emit light multiple times and adjust the Z axis of the processing head and the X axis (or Y axis) of the working surface multiple times. Therefore, it takes a long time to find the focus and the efficiency is low. Summary of the invention

[0004] The present application mainly provides a method for determining laser focus and a laser focus confirmation system to solve the problem of low efficiency in existing laser focus confirmation.

[0005] In order to solve the above technical problems, a technical solution adopted by the present application is: to provide a method for determining the laser focus. The method for determining the laser focus includes: placing a reference block on a processing plane, wherein the reference block includes a slope surface; using continuous light to form a linear laser scratch on the slope surface, the head and tail of the linear laser scratch form a height difference on the slope surface, the middle weld mark of the linear laser scratch is clear and the head and tail weld marks are blurred; confirming that the position point where the width of the middle weld mark is the smallest and in the middle of the head and tail weld marks is the laser focus.

[0006] In some embodiments, a scale is provided on the reference block;

[0007] After confirming that the position point where the width of the middle weld mark is the smallest and located in the middle of the first and last weld marks is the laser focus, the method further includes:

[0008] The distance between the laser focus and the processing plane is confirmed by referring to the scale and the position of the laser focus.

[0009] In some embodiments, the scale is disposed on a side of the reference block, and a zero position of the scale is flush with a bottom surface of the reference block.

[0010] In some embodiments, the slope surface of the reference block is provided with a replaceable photosensitive material layer;

[0011] The method of forming a linear laser scratch on the slope surface by continuously emitting light comprises:

[0012] A linear laser scratch is formed on the photosensitive material layer by using continuous light output.

[0013] In some embodiments, the photosensitive material layer includes photographic paper and a metal sheet, and the thickness of the metal sheet is 0.1-0.5 mm.

[0014] In some embodiments, the photosensitive material layer is photographic paper;

[0015] The method of forming a linear laser scratch on the photosensitive material layer by continuously emitting light comprises:

[0016] The laser adopts a continuous light emitting mode to form the linear laser scratches on the photographic paper at a minimum light emitting power and a light emitting speed of 300 to 800 mm / s.

[0017] In some embodiments, the photosensitive material layer is a metal sheet, and the metal sheet includes an aluminum sheet and a stainless steel sheet;

[0018] The method of forming a linear laser scratch on the photosensitive material layer by continuously emitting light comprises:

[0019] The laser uses a continuous light emission mode to form the linear laser scratch on the aluminum plate with a light emission power of 500 to 800 W and a light emission speed of 100 to 300 mm / s; or

[0020] The laser adopts a continuous light emitting mode, and forms the linear laser scratches on the stainless steel plate with a light emitting power of 300-600W and a light emitting speed of 100-500mm / s.

[0021] In some embodiments, the flatness of the bottom surface of the reference block is less than or equal to 0.2 mm, and the slope angle of the slope surface is 30°-60°.

[0022] In some embodiments, an angle formed between the linear laser scratch and the processing plane is the same as the slope angle.

[0023] In order to solve the above technical problems, another technical solution adopted by the present application is: to provide a laser focus confirmation system. The laser focus confirmation system includes a laser, a reference block and a processing table, wherein the reference block is placed on the processing table, and the laser forms a linear laser scratch on the slope surface of the reference block in a continuous light emission mode; wherein the head and tail of the linear laser scratch form a height difference on the slope surface, the middle weld mark of the linear laser scratch is clear and the head and tail weld marks are blurred; the position point where the width of the middle weld mark is the smallest and in the middle of the head and tail weld marks is confirmed as the laser focus.

[0024] The beneficial effect of the present application is that, different from the prior art, the present application discloses a method for determining laser focus and a laser focus confirmation system. By placing a reference block on a processing plane and using a continuous light emission method to form a linear laser scratch on the slope surface at one time, and taking the position point where the width of the middle weld mark is the smallest and in the middle of the first and last weld marks as the laser focus, the laser focus can be confirmed by emitting light once, which greatly improves the efficiency of confirming the laser focus. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0026] Figure 1 It is a structural schematic diagram of an embodiment of a laser focus confirmation system provided by the present application;

[0027] Figure 2 It is a flow chart of an embodiment of a method for confirming laser focus provided by the present application;

[0028] Figure 3 yes Figure 1 The side view structural diagram of the laser focus confirmation system reference block is shown. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] The terms "first", "second", "third" in the embodiments of the present application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second", "third" can expressly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] The present application also provides a laser focus confirmation system 100, see Figure 1 , Figure 1 It is a structural schematic diagram of an embodiment of a laser focus confirmation system provided in the present application.

[0033] The laser focus confirmation system 100 includes a laser 30, a reference block 10 and a processing table 20. The reference block 10 is placed on the processing table 20. A replaceable photosensitive material layer 14 may be provided on the slope surface 12 of the reference block 10. The laser forms a linear laser scratch on the slope surface 12 of the reference block 10 or its photosensitive material layer 14 in a continuous light emitting manner; wherein the head and tail of the linear laser scratch form a height difference on the slope surface 12, the middle weld mark of the linear laser scratch is clear and the head and tail weld marks are blurred; confirm that the position point where the width of the middle weld mark is the smallest and is in the middle of the head and tail weld marks is the laser focus.

[0034] The present application also provides a method for determining the laser focus, see Figure 1 and Figure 2 , Figure 2 1 is a flow chart of an embodiment of a method for determining a laser focus provided by the present application. The method for determining a laser focus comprises:

[0035] Step 10: Place a reference block on a processing plane, wherein the reference block includes a slope surface.

[0036] The reference block 10 is positioned on the processing plane 20 to ensure that the bottom surface 11 of the reference block 10 is attached to the processing plane 20 .

[0037] The reference block 10 includes a bottom surface 11 and a slope surface 12 inclined relative to the bottom surface 11 , and a side surface 13 perpendicular to the bottom surface 11 . The side surface 13 connects the bottom surface 11 and the slope surface 12 . The bottom surface 11 can be placed on the processing plane 20 .

[0038] The flatness of the bottom surface 11 of the reference block 10 is less than or equal to 0.2 mm, which can ensure that the reference block 10 can be flat on the processing plane 20, ensuring the flatness quality. The slope surface 12 is an inclined plane, and the angle formed between it and the bottom surface 11 is the slope angle. The slope angle of the slope surface 12 is 30°-60°, so that a linear laser scratch that can clearly distinguish the laser focus can be formed on the slope surface 12. For example, the slope angle of the slope surface 12 is 30°, 45° or 60°.

[0039] Step 20: A linear laser scratch is formed on the slope surface by using continuous light. The beginning and the end of the linear laser scratch form a height difference on the slope surface. The middle weld mark of the linear laser scratch is clear, and the weld marks at the beginning and the end are blurred.

[0040] The laser 30 uses a continuous light emission mode to form a linear laser scratch on the slope surface 12. By editing the laser light emission trajectory, the angle formed between the linear laser scratch and the processing plane 11 can be made the same as the slope angle.

[0041] For example, if the slope angle is 45°, the angle formed between the linear laser scratch and the processing plane 11 can also be 45°, which can maximize the height difference between the beginning and the end of the linear laser scratch, thereby forming a linear laser scratch with more obvious weld mark characteristics.

[0042] The linear laser scratch formed by continuous light emission has the characteristics of the width of the laser scratch and whether the beginning and end of the scratch are clear, so that the middle weld mark of the linear laser scratch formed on the slope surface 12 is clear and the beginning and end weld marks are blurred. These weld mark characteristics are helpful for the subsequent determination of the laser focus.

[0043] Alternatively, linear laser scratches may be formed directly on the reference block 10 .

[0044] In this embodiment, the slope surface 12 of the reference block 10 is provided with a replaceable photosensitive material layer 14 .

[0045] Step 20 specifically includes: forming a linear laser scratch on the photosensitive material layer 14 by using continuous light output.

[0046] By providing a replaceable photosensitive material layer 14 on the slope surface 12 and forming a linear laser scratch on the photosensitive material layer 14, after the laser focus is confirmed by the linear laser scratch, a new photosensitive material layer 14 can be replaced to replace the reference block 10. That is, by replacing the photosensitive material layer 14, the reference block 10 can be reused, effectively saving the material cost of determining the laser focus each time.

[0047] The photosensitive material layer 14 is a thin layer with uniform thickness, which is attached to the slope surface 12. It can be fixed to the slope surface 12 by screws, or can be kept on the slope surface by cooperating with the limiting structure on the slope surface 12. For example, the four corners of the slope surface are provided with blocks to stop the photosensitive material layer 14.

[0048] Specifically, the photosensitive material layer 14 may include photographic paper and a metal sheet, wherein the thickness of the metal sheet is 0.1-0.5 mm. The photographic paper or the metal sheet is used to receive laser light and is formed with linear laser scratches.

[0049] Among them, the photo paper has a high absorption rate for laser, and is easy to form linear laser scratches with obvious trace characteristics. The metal sheet can be an aluminum oxide sheet, which also has a high absorption rate for laser.

[0050] The metal sheet can be an aluminum sheet or a stainless steel sheet with a thickness of 0.1-0.5 mm, specifically 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm. The linear laser scratches formed thereon will not penetrate the metal sheet of this thickness, and the material cost of the metal sheet within this thickness range is also extremely low, which is suitable for long-term and large-scale use.

[0051] In one embodiment, the photosensitive material layer 14 is photographic paper, and step 20 specifically includes: the laser uses a continuous light emitting mode to form a linear laser scratch on the photographic paper with a minimum light emitting power and a light emitting speed of 300-800 mm / s.

[0052] The light emitting mode is continuous light emitting, and the corresponding laser is a continuous laser or a quasi-continuous laser.

[0053] The absorption rate of the alumina plate to the laser is comparable to that of the photographic paper. Since these two materials have high absorption rates to light, the laser power of the laser is set to the minimum light output power, which is usually 10% of the maximum power of the laser. The light output speed is 300 to 800 mm / s, which can leave a laser mark, i.e., a linear laser scratch, on the photographic paper or the alumina plate without penetrating the photographic paper or the alumina plate.

[0054] In the above manner, clear linear laser scratches can be made on photographic paper or anodized aluminum plates, which helps users to accurately confirm the position of the laser focus by visual inspection.

[0055] In another embodiment, the photosensitive material layer 14 is a metal thin plate, and the metal thin plate is an aluminum plate, then step 20 specifically includes: the laser adopts a continuous light emitting mode, with a light emitting power of 500-800W and a light emitting speed of 100-300mm / s to form the linear laser scratch on the aluminum plate.

[0056] Alternatively, if the metal sheet is a stainless steel sheet, step 20 specifically includes: the laser uses a continuous light emitting mode to form the linear laser scratch on the stainless steel sheet with a light emitting power of 300 to 600 W and a light emitting speed of 100 to 500 mm / s.

[0057] When an aluminum plate or a stainless steel plate is used as the replaceable photosensitive material layer 14, a weld mark needs to be made on the surface of the plate, and the laser focus is determined according to the clarity of the weld. Therefore, the required light output power is relatively high.

[0058] In the above manner, a weld mark with a clear middle and blurred beginning and end can be produced on an aluminum plate or a stainless steel plate, which is helpful for determining the position of the laser focus based on the characteristics of the weld.

[0059] Step 30: Confirm that the point where the width of the middle weld mark is the smallest and in the middle of the first and last weld marks is the laser focus.

[0060] After the laser beam is focused by a lens or other optical element, the minimum spot size in space is called the focus. The laser energy density at the laser focus is the highest, and it is usually also the location where the laser interacts most strongly with the material. Therefore, accurately determining the laser focus of the laser 30 is beneficial to the subsequent laser processing efficiency and processing effect.

[0061] The laser 30 also has a focal depth, which refers to the distance within a certain range before and after the laser focus where the laser spot size does not change much and its energy density is still sufficient for effective processing. In other words, the focal depth refers to the spatial range in which the laser beam maintains effective processing capabilities.

[0062] Therefore, the laser scratches on the slope surface 12 within the focal depth range or the photosensitive material layer 14 within the range are relatively clear, which are usually located in the middle area of ​​the linear laser scratches, while the laser scratches at the head and tail ends are blurred. The more focused the laser is where the weld mark is clear, the smaller the width of the weld mark is. Therefore, the width of the weld mark in the focal and focal depth areas is the smallest. Therefore, the spot size difference in the focal depth area including the focus is very small, and there are several cases where the spot sizes are almost the same. Therefore, based on the blurred characteristics of the head and tail weld marks of the linear laser scratches, the point where the width of the middle weld mark is the smallest and located in the middle of the head and tail weld marks is taken as the laser focus.

[0063] See also Figure 3 , Figure 3 yes Figure 1 The schematic diagram of the side view structure of the reference block of the laser focus confirmation system is shown. Further, a scale 15 is provided on the reference block 10, and the scale 15 can be provided on the side surface 13 or the slope surface 12 of the reference block 10. The distance from each position to the processing plane 20 is marked on the scale 15, so after confirming the position of the laser focus, the distance between the laser focus and the processing plane 20 can be confirmed by referring to the scale 15.

[0064] After step 30, step 40 is also included: referring to the position of the scale and the laser focus to confirm the distance between the laser focus and the processing plane.

[0065] After confirming the distance between the laser focus and the processing plane 20 , the laser can be adjusted during subsequent laser processing so that its laser focus is located on the processing plane 20 , thereby improving processing efficiency and processing quality.

[0066] In this embodiment, the scale 15 is arranged on the side 13 of the reference block 10. The scale 15 can be distributed in a direction perpendicular to the bottom surface 11, or the scale 15 is distributed in a direction flush with the slope surface 12, and the zero position of the scale 15 is flush with the bottom surface 11 of the reference block 10. Therefore, based on the scale 15, the distance between the current laser focus and the processing plane 20 can be quickly determined.

[0067] Different from the prior art, the present application discloses a method for determining laser focus and a laser focus confirmation system. By placing a reference block on a processing plane and using a continuous light emission method to form a linear laser scratch on the slope surface at one time, and taking the position point where the width of the middle weld mark is the smallest and in the middle of the first and last weld marks as the laser focus, the laser focus can be confirmed by emitting light once, which greatly improves the efficiency of confirming the laser focus.

[0068] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for determining a laser focus, characterized in that: include: placing a reference block on a processing plane, wherein the reference block comprises a slope surface; A linear laser scratch is formed on the slope surface by continuous light emission, the head and tail of the linear laser scratch form a height difference on the slope surface, the middle weld mark of the linear laser scratch is clear and the head and tail weld marks are blurred; It is confirmed that the position point where the width of the middle weld mark is the smallest and is in the middle of the first and last weld marks is the laser focus.

2. The method for determining laser focus according to claim 1, characterized in that: The reference block is provided with a scale; After confirming that the position point where the width of the middle weld mark is the smallest and located in the middle of the first and last weld marks is the laser focus, the method further includes: The distance between the laser focus and the processing plane is confirmed by referring to the scale and the position of the laser focus.

3. The method for determining laser focus according to claim 2, characterized in that: The scale is arranged on the side of the reference block, and the zero position of the scale is flush with the bottom surface of the reference block.

4. The method for determining laser focus according to claim 1, characterized in that: The slope surface of the reference block is provided with a replaceable photosensitive material layer; The method of forming a linear laser scratch on the slope surface by continuously emitting light comprises: A linear laser scratch is formed on the photosensitive material layer by using continuous light output.

5. The method for determining laser focus according to claim 4, characterized in that: The photosensitive material layer includes photographic paper and a metal sheet, and the thickness of the metal sheet is 0.1-0.5 mm.

6. The method for determining laser focus according to claim 5, characterized in that: The photosensitive material layer is photographic paper; The method of forming a linear laser scratch on the photosensitive material layer by continuously emitting light comprises: The laser adopts a continuous light emitting mode to form the linear laser scratches on the photographic paper at a minimum light emitting power and a light emitting speed of 300 to 800 mm / s.

7. The method for determining laser focus according to claim 5, characterized in that: The photosensitive material layer is a metal thin plate, and the metal thin plate includes an aluminum plate and a stainless steel plate; The method of forming a linear laser scratch on the photosensitive material layer by continuously emitting light comprises: The laser uses a continuous light emission mode to form the linear laser scratch on the aluminum plate with a light emission power of 500 to 800 W and a light emission speed of 100 to 300 mm / s; or The laser adopts a continuous light emitting mode, and forms the linear laser scratches on the stainless steel plate with a light emitting power of 300-600W and a light emitting speed of 100-500mm / s.

8. The method for determining laser focus according to claim 1, characterized in that: The flatness of the bottom surface of the reference block is less than or equal to 0.2 mm, and the slope angle of the slope surface is 30°-60°.

9. The method for determining laser focus according to claim 8, characterized in that: The angle formed between the linear laser scratch and the processing plane is the same as the slope angle.

10. A laser focus confirmation system, characterized in that: The laser focus confirmation system comprises a laser, a reference block and a processing table, wherein the reference block is placed on the processing table, and the laser forms a linear laser scratch on the slope surface of the reference block in a continuous light emitting manner; Among them, the head and tail of the linear laser scratch form a height difference on the slope surface, the middle weld mark of the linear laser scratch is clear and the head and tail weld marks are blurred; confirm that the position point where the width of the middle weld mark is the smallest and in the middle of the head and tail weld marks is the laser focus.

Images