Infrared laser marking of nylon materials

Abstract

The application provides an infrared laser marking method for nylon material, relates to the field of laser processing technology, and comprises the following steps: turning on an infrared nanosecond fiber laser, adjusting the focal length of the laser, and focusing the laser focal point on the surface to be machined of a part body made of nylon material; controlling the laser focal point to move on the surface to be machined of the part body according to a preset path, and forming a mark corresponding to the preset path, wherein the peak power of the infrared nanosecond fiber laser is 30-60 kW. The application uses an infrared nanosecond fiber laser instead of an ultraviolet laser, can not only obtain clear white or light-colored marks, but also can reduce the equipment cost. Moreover, the application can overcome the problem that the infrared light absorption rate of the nylon material is low and the infrared laser is difficult to excite the foaming agent in the nylon material, and clear white or light-colored marks can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser processing technology, in particular to an infrared laser marking method for nylon material. BACKGROUND

[0002] Nylon material has excellent comprehensive performance and is widely used in the fields of automobiles, electronics, etc. The materials used in these fields need good flame retardancy, but nylon material itself cannot meet the requirements. Therefore, in order to improve the flame retardancy of nylon material, various flame retardants are often added. Among them, dark flame-retardant nylon material added with carbon black, graphite, iron oxide and other additives is one of the commonly used flame-retardant nylon materials.

[0003] At present, the light-colored marks on nylon products are generally obtained by adding additives such as talc powder to the nylon material, and the foaming agent is excited to produce foaming by laser heating, so that the surface light reflection of the laser irradiated part is increased, and white or light-colored marks are obtained. However, the absorption rate of nylon to infrared laser is low, and the existing infrared laser is difficult to excite the foaming agent in the nylon material to produce foaming, so that clear white or light-colored marks cannot be obtained. The absorption rate of carbon black, graphite, iron oxide and other additives in nylon material to ultraviolet laser is very high. The higher the content of these additives, the higher the heat absorbed, which is easy to cause the area irradiated by laser to be heated and volatilized, resulting in the depression of the area, and bright marks cannot be produced. Moreover, compared with infrared laser, ultraviolet nanosecond laser is expensive. SUMMARY

[0004] To solve the problems in the prior art, the present application aims to provide an infrared laser marking method for nylon material, which comprises the following steps:

[0005] Turn on the infrared nanosecond fiber laser, adjust the laser focal length, and focus the laser focal point on the surface to be processed of the part body made of nylon material.

[0006] Control the laser focal point to move on the surface to be processed of the part body according to the preset path, form marks corresponding to the preset path, and the peak power of the infrared nanosecond fiber laser is 30-60kW.

[0007] Compared with the prior art, the present application has the following advantages:

[0008] (1) The infrared laser marking method for nylon material provided by the present application uses an infrared nanosecond fiber laser instead of an ultraviolet laser, which not only can obtain clear white or light-colored marks, but also can reduce the cost of equipment.

[0009] (2) The surface of the nylon material is irradiated by an infrared nanosecond fiber laser with a peak power of 30-60kW, so as to overcome the problem that the existing infrared laser is difficult to excite the foaming agent in the nylon material due to the low absorption rate of the nylon material to infrared light, and clear white or light-colored marks are obtained.

[0010] (3) And because the absorption rate of the nylon material to the infrared laser is low, the laser energy irradiated to the surface of the nylon material is easier to control, so as to prevent the area irradiated by the laser from being heated and volatilized, and make the area concave. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 Flow chart of the infrared laser marking method for the nylon material according to an embodiment of the present application;

[0012] Figure 2 Schematic diagram of the jitter trajectory of the laser focus according to an embodiment of the present application;

[0013] Figure 3 Planar enlarged photo of the machining trace on the component body according to Example 1 of the present application;

[0014] Figure 4 Planar enlarged photo of the machining trace on the component body according to Comparative Example 1 of the present application;

[0015] Figure 5 Planar enlarged photo of the white square grid machined on the component body according to Example 2 of the present application;

[0016] Figure 6 Planar enlarged photo of the white square grid machined on the component body according to Comparative Example 2 of the present application.

[0017] Wherein, m: laser focus; r: jitter radius; d: jitter interval; a: machining trace; b: white square grid. EMBODIMENT

[0018] It should be understood that the specific embodiments described herein are merely intended to explain the present application, and are not intended to limit the present application.

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] It should be noted that all directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications will also change accordingly. The connection can be direct connection or indirect connection.

[0021] In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person of ordinary skill in the art, and when the combination of technical solutions is contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0022] The nylon material in the present application is a polyamide fiber material added with a dark color flame retardant, and a black, dark blue, brown or dark green dyeing agent can also be added. The dark color in the present application refers to a dark color, and the saturation and lightness are both less than 50%. The product made of dark nylon material generally has a dark surface, and a foaming agent is generally added when using laser to mark. The foaming agent reacts photochemically with the laser to produce foaming phenomenon, and clear marks are obtained. The marks are not easy to wear and can be kept for a long time. The foaming phenomenon refers to that part of the components inside the nylon material reacts photochemically to produce gas after being irradiated by laser. The gas is wrapped by the nylon material, and a mixed phase with high refractive index can be obtained by irradiating with appropriate laser energy, which presents a light-colored mark at the foaming site.

[0023] As shown in an embodiment of the infrared laser marking method of the nylon material, the method comprises the following steps: Figure 1

[0024] S1: Turn on the infrared nanosecond fiber laser, adjust the laser focal length, and focus the laser focal point on the surface to be processed of the component body made of nylon material.

[0025] The absorption rate of the nylon material to the infrared laser is low, which can prevent the nylon material from being gasified and the foaming phenomenon from occurring. Moreover, the cost of the infrared nanosecond fiber laser is only one tenth of that of the nanosecond ultraviolet laser, which can effectively control the cost. In the present embodiment, the component body made of nylon material is sensitive to the focal point of the infrared nanosecond fiber laser, and the precision of the laser focal point needs to be ensured. The surface to be processed of the component body is the plane that needs to be laser marked, and needs to be installed upward during installation.

[0026] S2: Control the laser focal point to move on the surface to be processed of the component body according to a preset path, form a mark corresponding to the preset path, and the peak power of the infrared nanosecond fiber laser is 30-60kW.

[0027] ​The nylon material in the component body has a low absorption rate of infrared laser, and can reduce the degree of reaction of the foaming agent and laser powder in the component body with the infrared laser to some extent. In order to cause foaming, the nylon material must absorb enough energy to become a molten state, and the foaming agent and laser powder wrapped therein must absorb enough energy to cause a photochemical reaction to generate gas, supporting the molten nylon material to form a micro cavity. Therefore, it is necessary to increase the peak power of the infrared nanosecond fiber laser. When the peak power of the infrared nanosecond fiber laser is 30-60kW, the energy requirements of the nylon material and the foaming agent and laser powder to cause foaming can be met, and the nylon material will not volatilize due to excessive energy.

[0028] The peak power can be 30kW, 31kW, 32kW, 33kW, 34kW, 35kW, 36kW, 37kW, 38kW, 39kW, 40kW, 40kW, 41kW, 42kW, 43kW, 44kW, 45kW, 46kW, 47kW, 48kW, 49kW, 50kW, 51kW, 52kW, 53kW, 54kW, 55kW, 56kW, 57kW, 58kW, 59kW, 60kW, or a non-integer peak power can also be selected. Through experiments, an infrared laser with a peak power of 30-60kW can overcome the problem of low absorption rate of non-metals to infrared light, so that the nylon material can be heated to a molten state suitable for foaming reaction in a short time.

[0029] The preset path can be designed by computer design software according to the required pattern or character shape, and after the design is completed, a file that can be used by a laser device is exported. In use, the focus of the infrared laser moves on the surface of the component body according to the preset path to form a light-colored mark.

[0030] Preferably, the peak power of the infrared nanosecond fiber laser can be increased by increasing the pulse energy, reducing the pulse width, and replacing the lens with a higher pulse laser damage threshold. In actual production, other methods for increasing the peak power can also be used.

[0031] The infrared laser marking method for nylon material provided by the embodiment uses an infrared nanosecond fiber laser instead of an ultraviolet laser, which not only can obtain clear white or light-colored marks, but also can reduce the cost of the equipment. Moreover, the peak power of the infrared nanosecond fiber laser is adjusted to 30-60kW, which overcomes the problem that the nylon material has a low absorption rate of infrared light and it is difficult to excite the foaming agent in the nylon material with the infrared laser, so that clear white or light-colored marks can be obtained. By taking advantage of the low absorption rate of nylon material to infrared laser, the nylon material is prevented from being heated and volatilized, and the area irradiated by the laser is prevented from being depressed.

[0032] The infrared laser marking method of the nylon material provided by the embodiment has an infrared nanosecond fiber laser with a wavelength of 760-3800 nm and a pulse width of 1-9 ns. The shorter wavelength can reduce the diffraction limit, which is conducive to fine focusing and improves the processing quality. The infrared nanosecond fiber laser with a pulse width of 1-9 ns can not only meet the requirement of the peak power of the embodiment, but also has a price advantage compared with an ultrafast laser. In addition, the smaller pulse width can make the peak power easier to increase.

[0033] Further preferably, the infrared nanosecond fiber laser has a wavelength of 1064 nm and a pulse width of 5 ns.

[0034] In the embodiment, the speed of moving along the preset path is 800-1200 mm / s, and the frequency is 25-45 KHz. Further preferably, the speed of moving along the preset path is 1000 mm / s, and the frequency is 30 KHz.

[0035] The faster the speed of moving along the preset path of the laser focal point, the shorter the time of staying at the same position, and the more energy absorbed by the nylon material at the position. The moving speed range given by the embodiment can make the nylon material irradiated by the laser absorb enough energy to generate a foaming reaction, and will not be gasified due to too much absorbed energy.

[0036] In the embodiment, the laser focal point moves along the preset path while being laterally dithered in a direction perpendicular to the preset path.

[0037] The lateral dithering of the infrared nanosecond fiber laser can be achieved by controlling the movement path of the galvanometer of the infrared nanosecond fiber laser. The focal point of the infrared laser on the surface coating also dithers, and the dithering direction changes with the position of the focal point on the preset path, so that the dithering direction of the focal point is perpendicular to the preset path at any position on the preset path. The focal point of the infrared nanosecond fiber laser is small, and the processing width is narrow when moving along the preset path. After dithering, the processing width can be improved, thereby improving the processing efficiency.

[0038] In the embodiment, the path of the laser focal point after being laterally dithered in a direction perpendicular to the preset path is a spring-shaped spiral line. As shown in Figure 2 The path of the laser focal point is a spring-shaped spiral line, and the laser focal point m is circular, as shown in Figure 2The spring-shaped spiral line shown is scanned, and the straight arrow direction in the figure is the preset path direction. Overlapping occurs at the edge position of the path, that is, repeated scanning occurs at the edge. The laser focus m repeatedly scans the same position of the component body, can react with the unreacted laser powder in the nylon material after the nylon material slightly cools, increases the number of air cavities in the foaming phenomenon, and improves the processing quality of the position, so that the edge of the mark processed in the embodiment is clearer.

[0039] In the embodiment, the shaking radius r of the transverse shaking is 0.08 mm. As shown in the figure, Figure 2 The shaking radius r is the maximum offset distance of the focus point shaking transversely perpendicular to the preset path, and 2r is twice the shaking radius r.

[0040] In the embodiment, the shaking interval d of the transverse shaking is 0.05 mm. As shown in the figure, Figure 2 The shaking interval d is the moving distance of the focus point along the preset path direction between two times of shaking.

[0041] The focus point of the infrared nanosecond fiber laser is small, the track processed by moving the focus point along the preset path is narrow, and multiple processing tracks are needed to combine to form a corresponding mark. The embodiment makes the infrared nanosecond fiber laser shake, and the laser focus point moves transversely perpendicular to the preset path on the component body, which can widen the processing track and reduce the total length of the preset path when combined into a mark, thereby improving the processing efficiency.

[0042] In the embodiment, the nylon material includes glass fibers.

[0043] The addition of glass fibers in the nylon material can improve the hardness of the nylon material, and the glass fibers have a binding effect on the nylon material. During the foaming reaction, the nylon material will be difficult to be blown up by the gas generated by the foaming agent to form a small air cavity, so the foaming reaction will become difficult, and it is difficult to obtain a clear mark using the existing laser marking technology. However, in the embodiment, the laser powder can generate more gas, and compared with the existing infrared laser, the peak power of the infrared nanosecond fiber laser provided by the embodiment is 30-60 kW, which can generate infrared laser with higher instantaneous energy, reduce the binding effect of glass fibers on the nylon material, promote the foaming reaction, and thus improve the clarity of the mark.

[0044] In the embodiment, the component body is obtained by mixing laser powder into nylon material and injection molding; the added amount of laser powder is 0.1%-0.5%. The laser powder is also called laser additive, laser engraving powder, laser master batch, etc. The laser powder can convert laser beam into heat energy by absorbing laser energy, and has the effects of heating, carbonization, evaporation and chemical reaction on the base material, so as to make the base material more easily marked by laser, or improve the clarity of laser marking. Different laser powders can be selected for different base materials. In the application, the laser powder used in the nylon material needs to be selected, and the light color needs to be marked on the dark base. The addition of laser powder in the application can promote the foaming phenomenon, so that the obtained mark is clearer. The market price of laser powder is relatively high. In the embodiment, the added amount of laser powder is 0.1%-0.5%, which is lower than that of the prior art, and good marking effect can still be achieved through the embodiment, so as to reduce the cost.

[0045] Next, the infrared laser marking method of the component body made of nylon material is described based on the comparative test. Example 1

[0046] First, 0.3% of laser powder is mixed into the nylon material containing glass fiber, and the component body is obtained by injection molding. The nylon material contains black dye, and the surface of the component body is provided with a groove. The bottom of the groove needs to be marked by laser as white to reduce the wear of the white bottom edge and improve the service life of the mark.

[0047] An infrared nanosecond fiber laser with a wavelength of 1064 nm and a pulse width of 5 ns is selected. The component body is placed on the processing table of the infrared nanosecond fiber laser, the infrared nanosecond fiber laser is turned on, the laser focal length is adjusted, and the laser focal point is focused on the surface to be processed of the component body.

[0048] The process parameters are set by the marking software of the infrared nanosecond fiber laser, the peak power is adjusted to 40-45 kW, which can be adjusted to 40 kW, 41 kW, 42 kW, 43 kW, 44 kW or 45 kW, or a non-integer. The speed of moving according to the preset path is adjusted to 1000 mm / s, and the frequency is 30 KHz. The laser focal point is controlled to move on the surface to be processed of the component body according to the preset path, and a mark corresponding to the preset path is formed.

[0049] As shown in Figure 3 , it is a planar enlarged photo of the processing trace on the component body obtained by example 1. As shown in Figure 4The image shown is a magnified planar photograph of the machining marks on the component body of Comparative Example 1. Compared to Example 1, the peak power of the infrared laser used in Comparative Example 1 is approximately 20kW, and the composition and shape of the component body, as well as other laser marking parameter settings, are the same as in Example 1.

[0050] Figure 3 and Figure 4 The machining marks 'a' in Comparative Example 1 are all straight lines. It can be seen that the machining marks in Comparative Example 1 are darker in color, uneven in color, and have rough edges. In contrast, the machining marks 'a' in Example 1 are whiter, more uniform in color, and have smooth edges. Furthermore, observing the machining marks 'a' of Comparative Example 1 and Example 1 with the naked eye from a top-down view yields the following impressions: the machining marks 'a' in Comparative Example 1 are grayish in color and have low contrast with the black part. In contrast, the machining marks 'a' in Example 1 are whiter, have higher contrast, and are clearer. Example 2

[0051] Example 2 is a further improvement on Example 1. Unlike Example 1, Example 2 marks a QR code on a flat surface of the component body. Furthermore, in Example 2, the marking software of the external nanosecond fiber laser controls the laser focus to move along a preset path while simultaneously jittering laterally in a direction perpendicular to the preset path. The path after the laser focus jitters laterally in the direction perpendicular to the preset path is a spring-like spiral. The jitter radius is 0.08 mm, and the jitter interval is 0.05 mm.

[0052] like Figure 5 The image shown is a magnified planar photograph of the white squares machined on the component body obtained through Example 2. Figure 6 The image shown is a magnified planar photograph of the white squares processed on the component body of Comparative Example 2. Both Example 2 and Comparative Example 2 require processing a QR code composed of white squares onto the surface of the component body. Compared to Example 2, Comparative Example 2 uses an infrared laser with a peak power of approximately 20kW, the laser focus does not jitter during movement along a preset path, and the composition and shape of the component body, as well as other laser marking parameter settings, are the same as in Example 2.

[0053] It can be seen that the white square b in Comparative Example 2 is darker in color and uneven in color. The central part of white square b contains areas where the foaming reaction did not occur, and the edges of white square b are rough. In contrast, the white square b in Example 2 is whiter, has a more uniform color, and smoother edges. Furthermore, observing the white square b of Comparative Example 2 and Example 2 with the naked eye from a top-down view yields the following impressions: the white square b of Comparative Example 2 is grayish in color and has low contrast with the black parts. The white square b of Example 2 is whiter, has higher contrast, and is clearer.

[0054] In summary, the application has the following beneficial effects:

[0055] (1) The infrared laser marking method of the nylon material provided by the application uses an infrared nanosecond fiber laser instead of an ultraviolet laser, which can not only obtain clear white or light-colored marks, but also reduce equipment costs.

[0056] (2) By irradiating the surface of the nylon material with an infrared nanosecond fiber laser with a peak power of 30-60kW, the problem of low infrared light absorption rate of nylon material and the difficulty of existing infrared lasers to excite the foaming agent in the nylon material are overcome, and clear white or light-colored marks are obtained.

[0057] (3) And because the absorption rate of the nylon material to the infrared laser is low, it is easier to control the laser energy irradiated to the surface of the nylon material, preventing the area irradiated by the laser from being heated and volatilized, and causing the area to be concave.

[0058] (4) By controlling the laser focus to be laterally dithered along a direction perpendicular to the preset path direction, the marking quality is further improved, the foaming reaction is more sufficient, the whiteness of the mark is improved, and the mark is clearer.

[0059] The above is only the preferred embodiment of the application, and does not limit the patent scope of the application, and any equivalent structure or equivalent flow transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the application.

Claims

1. An infrared laser marking method for nylon materials, characterized in that, Includes the following steps: Turn on the infrared nanosecond fiber laser, adjust the laser focal length, and focus the laser on the surface to be processed of the component body made of nylon material, wherein the nylon material contains a dark flame retardant and includes glass fiber; The laser focus is controlled to move along a preset path on the surface to be processed of the component body to form a light-colored mark corresponding to the preset path. The peak power of the infrared nanosecond fiber laser is 30-60kW. The component body is obtained by mixing laser powder into the nylon material and then injection molding; the amount of laser powder added is 0.1%-0.5%.

2. The infrared laser marking method for nylon materials according to claim 1, characterized in that, The infrared nanosecond fiber laser has a wavelength of 760-3800nm ​​and a pulse width of 1-9ns.

3. The infrared laser marking method for nylon materials according to claim 1, characterized in that, The speed of movement along the preset path is 800-1200 mm / s, and the frequency is 25-45 kHz.

4. The infrared laser marking method for nylon materials according to claim 1, characterized in that, While moving along the preset path, the laser focus also jitters laterally in a direction perpendicular to the preset path.

5. The infrared laser marking method for nylon materials according to claim 4, characterized in that, The path of the laser focus after lateral jitter along a direction perpendicular to the preset path is a spring-shaped spiral.

6. The infrared laser marking method for nylon materials according to claim 5, characterized in that, The lateral jitter radius is 0.08 mm, which is the maximum offset distance of the laser focus perpendicular to the preset path during lateral jitter.

7. The infrared laser marking method for nylon materials according to claim 5, characterized in that, The lateral jitter interval is 0.05mm, and the jitter interval is the distance the laser focus moves along the preset path direction between two jitters.

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