Method for cutting silicon nitride ceramic based on laser

Abstract

The invention discloses a method for cutting silicon nitride ceramic based on laser. The invention provides a method for cutting silicon nitride ceramic based on laser. The method comprises the steps that a silicon nitride ceramic mold to be cut is fixed to a workbench of a laser cutting device through a clamp; setting laser processing parameters; coating an absorbent on a pre-cutting area of the silicon nitride ceramic; according to the cutting path and the laser processing parameters, a laser of a laser cutting device is used for cutting the silicon nitride ceramic, and continuous laser is used for moving and cutting on the surface of the silicon nitride ceramic along the set path; and auxiliary gas coaxial with the light beam is used for blowing away molten substances, and a cooling effect is achieved, so that continuous kerfs are formed on the surface of the silicon nitride ceramic, the laser absorptivity of the ceramic can be increased, and the processing efficiency and quality of the silicon nitride ceramic are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon nitride ceramic cutting, in particular to a method for cutting silicon nitride ceramic based on laser. BACKGROUND

[0002] Silicon nitride is an inorganic substance, which is an important structural ceramic material. It has high hardness, lubricity, wear resistance, and is an atomic crystal. It is also resistant to oxidation at high temperatures. Moreover, it can resist thermal shock and will not crack when heated to more than 1000℃ in air and then rapidly cooled and rapidly heated again. Due to its excellent properties, silicon nitride ceramic is often used to manufacture mechanical components such as bearings, gas turbine blades, mechanical seal rings, and permanent molds.

[0003] Silicon nitride ceramic has the characteristics of hardness and fragility, which makes it difficult to cut and process. Laser is a flexible, efficient and high-yield processing method, which has been applied in the cutting of silicon nitride ceramic plates. However, in the existing method for cutting silicon nitride ceramic based on laser, the absorption rate of laser is not good due to the smooth surface and high reflectivity of silicon nitride ceramic, and the appearance quality, kerf width and other aspects of the processed products do not meet the requirements. In the process of laser cutting ceramic, it is easy to appear jump line, light leakage, yellow and black cutting surface of ceramic, poor cutting quality and low cutting efficiency. Therefore, it is necessary to propose a method for cutting silicon nitride ceramic based on laser to solve the above problems. SUMMARY

[0004] The present application aims to solve the problem of the existing method for cutting silicon nitride ceramic based on laser, in which the absorption rate of laser is not good due to the smooth surface and high reflectivity of silicon nitride ceramic, and the appearance quality, kerf width and other aspects of the processed products do not meet the requirements.

[0005] The present application provides a method for cutting silicon nitride ceramic based on laser, which comprises:

[0006] Step one, fix the silicon nitride ceramic type to be cut by a clamp on the workbench of a laser cutting device;

[0007] Step two, set the laser processing parameters; wherein the laser processing parameters include the lead-out line and the lead-in line, and the lead arc hole is placed. When laser processing, the first hole appearing after the laser beam hits the silicon nitride ceramic is the lead arc hole. When setting the positions of the corresponding lead-in line and lead-out line, the lead-in line and lead-out line are obtained according to the relationship between the contours of the processed parts, the lead-out line and the lead-in line.

[0008] Step 3: Apply an absorbent to the pre-cut area of ​​the silicon nitride ceramic; the absorbent comprises the following components in the following mass ratio: 30% carmine red, 15% polyvinyl alcohol, 20% red ink, and 35% water;

[0009] Step four: According to the cutting path and laser processing parameters, the silicon nitride ceramic is cut using the laser of the laser cutting device. A continuous laser is used to move and cut along a set path on the surface of the silicon nitride ceramic; the laser is a carbon dioxide laser cutter.

[0010] Step 5: An auxiliary gas coaxial with the beam is used to blow away the molten material and cool it, thereby forming a continuous slit on the surface of the silicon nitride ceramic; the pressure of the auxiliary gas is 0.6 MPa.

[0011] Furthermore, in step two, the laser processing parameters include switching light compensation, which is performed with micron-level precision.

[0012] Furthermore, in step four, the frequency of the pulsed laser emitted by the laser is 750Hz.

[0013] Furthermore, in step four, the pulsed laser energy emitted by the laser is 55W.

[0014] Furthermore, in step four, the pulse width of the laser emitted by the laser is 300 microseconds.

[0015] Furthermore, in step four, the feed rate of the laser head of the laser is 5.5 mm / s.

[0016] Furthermore, in step five, the auxiliary gas is either nitrogen or air.

[0017] The present invention has the following beneficial effects: The present invention provides a method for laser cutting silicon nitride ceramics, wherein the silicon nitride ceramic model to be cut is fixed on the worktable of a laser cutting device by a clamp; laser processing parameters are set; an absorbent is applied to the pre-cutting area of ​​the silicon nitride ceramic; according to the cutting path and laser processing parameters, the laser of the laser cutting device is used to cut the silicon nitride ceramic, and a continuous laser is used to move and cut along the set path on the surface of the silicon nitride ceramic; an auxiliary gas coaxial with the beam is used to blow away the molten material and play a cooling role, thereby forming a continuous kerf on the surface of the silicon nitride ceramic, which can increase the absorption rate of the ceramic to the laser and improve the processing efficiency and quality of silicon nitride ceramics. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of the method for laser cutting silicon nitride ceramics according to the present invention. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be pointed out that the following detailed description is illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0021] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0022] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions has been enlarged, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0023] Please see Figure 1 This invention provides a method for laser cutting silicon nitride ceramics, comprising:

[0024] Step 1: Fix the silicon nitride ceramic model to be cut onto the worktable of the laser cutting device using a clamp.

[0025] To ensure the stability of silicon nitride ceramics during the cutting process, the fixture should be designed to be adjustable to accommodate ceramic parts of different sizes and shapes. At the same time, the worktable surface should be covered with a high-temperature resistant, low-friction protective pad to reduce direct contact between the ceramic parts and the worktable, preventing scratches or damage.

[0026] Step 2: Set the laser processing parameters; wherein, the laser processing parameters include lead-out lines and lead-in lines, and place the arc-starting hole. During laser processing, the first hole that appears after the laser beam hits the silicon nitride ceramic is the arc-starting hole; when setting the positions of the corresponding lead-in lines and lead-out lines, the lead-out lines and inner lead-out lines are obtained according to the relationship between the contours of the processed parts and the lead-out lines.

[0027] When setting up the lead-in and lead-out lines, their length, angle, and smooth transition with the cutting path must be considered to reduce stress concentration and crack formation during the cutting process. The position of the arc-starting hole should be precisely calculated to ensure that the laser beam can smoothly penetrate the ceramic surface and form a stable cutting starting point. In addition, intelligent algorithms can be introduced to automatically optimize the layout of the lead-in and lead-out lines based on the geometry and material properties of the ceramic part.

[0028] The ablation threshold of silicon nitride ceramics can be predetermined. The ablation threshold is the energy flux density required to remove a single layer of material when irreversible damage is caused. The energy density of a single-pulse laser largely determines the efficiency of laser ablation. The processing quality is best when the laser pulse energy is slightly higher than the ablation threshold; however, in reality, due to varying degrees of energy loss, under reasonable removal rate conditions, the best accuracy can be obtained by selecting a laser pulse with a power density 5-10 times that of the threshold. This avoids cracking caused by excessive energy and incomplete cutting or low efficiency caused by insufficient energy.

[0029] Laser processing parameters also include on / off beam compensation, which is performed with micron-level precision. Micron-level on / off beam compensation is crucial for improving cutting accuracy. A high-precision control system enables precise control of the laser beam's on and off moments, reducing unevenness on the cut surface caused by instantaneous energy fluctuations. Simultaneously, the laser beam's energy output can be monitored in real time, ensuring a stable energy level throughout the entire cutting process.

[0030] Step 3: Apply an absorbent to the pre-cut area of ​​the silicon nitride ceramic; the absorbent comprises the following components in the following mass ratio: 30% carmine red, 15% polyvinyl alcohol, 20% red ink, and 35% water;

[0031] The absorber formulation is carefully selected and proportioned to improve the absorption efficiency of laser energy on the silicon nitride ceramic surface. Carmine red serves as the primary laser absorber, significantly enhancing the interaction between the laser beam and the ceramic surface; polyvinyl alcohol acts as a binder, ensuring the absorber adheres firmly to the ceramic surface; red ink is used to adjust the absorber's color, facilitating observation and monitoring of the coating effect; and water acts as a solvent, ensuring uniform mixing of all components. Furthermore, the proportions of each component can be adjusted according to specific needs to achieve optimal cutting results.

[0032] This absorber, when coated onto the surface of silicon nitride ceramics, increases the absorption rate of laser light by the silicon nitride ceramics, significantly improving the laser processing efficiency of silicon nitride ceramics after coating. This absorber is a pollution-free and environmentally friendly material that does not increase environmental pollution during processing and does not affect the properties of the silicon nitride ceramics themselves.

[0033] Step four: According to the cutting path and laser processing parameters, the silicon nitride ceramic is cut using the laser of the laser cutting device. A continuous laser is used to move and cut along a set path on the surface of the silicon nitride ceramic; the laser is a carbon dioxide laser cutter.

[0034] A carbon dioxide laser cutter was chosen because of its excellent performance in cutting non-metallic materials, especially suitable for processing hard and brittle materials such as silicon nitride ceramics. This laser has high energy density and good beam quality, ensuring the stability and efficiency of the cutting process. Furthermore, parameters such as the laser's output power, frequency, and pulse width can be adjusted according to cutting needs to meet the cutting requirements of ceramic parts of different thicknesses and shapes.

[0035] The laser emits a pulsed laser frequency of 750Hz. The pulsed laser energy is 55W. The pulse width is 300 microseconds. The laser head's feed rate is 5.5mm / s. The pulsed laser parameters are optimized to balance cutting speed and quality. The laser head's feed rate is also precisely calculated to ensure accurate cutting paths and a smooth cut surface. Furthermore, these parameters can be dynamically adjusted based on real-time feedback during the cutting process to address minute changes or defects on the ceramic part's surface.

[0036] Step 5: An auxiliary gas coaxial with the beam is used to blow away the molten material and cool it, thereby forming a continuous slit on the surface of the silicon nitride ceramic; the pressure of the auxiliary gas is 0.6 MPa.

[0037] Specifically, the auxiliary gas is either nitrogen or air. Nitrogen or air is chosen as the auxiliary gas because they offer good cooling and purging capabilities. Nitrogen, due to its inert nature, reduces oxidation during the cutting process, protecting the surface quality of the ceramic parts; while air is less expensive and readily available. Regardless of the gas chosen, its pressure must be precisely controlled to ensure that the auxiliary gas can uniformly and stably remove molten material and debris while providing good cooling. Furthermore, the auxiliary gas delivery pipes and nozzles must be regularly inspected and cleaned to prevent blockages or impaired purging performance.

[0038] As can be seen from the above embodiments, the present invention provides a method for laser cutting silicon nitride ceramics, which involves fixing the silicon nitride ceramic model to be cut on the worktable of a laser cutting device using a clamp; setting laser processing parameters; applying an absorbent to the pre-cutting area of ​​the silicon nitride ceramic; cutting the silicon nitride ceramic using the laser of the laser cutting device according to the cutting path and laser processing parameters; using a continuous laser to move and cut along a set path on the surface of the silicon nitride ceramic; and using an auxiliary gas coaxial with the beam to blow away molten material and cool it, thereby forming a continuous kerf on the surface of the silicon nitride ceramic. This method can increase the absorption rate of the ceramic to the laser and improve the processing efficiency and quality of silicon nitride ceramics.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in sequences other than those illustrated or described herein.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of laser cutting silicon nitride ceramic based on the steps of, The application relates to a laser cutting method for silicon nitride ceramic. Step one, fixing the silicon nitride ceramic to be cut by a clamp on the workbench of a laser cutting device; Step two, setting laser processing parameters; wherein the laser processing parameters include an outgoing line and an incoming line, and an arc hole is placed; when laser processing is performed, the first hole appearing after the laser beam hits the silicon nitride ceramic is the arc hole; when the positions of the corresponding incoming line and outgoing line are set, the relationship among the profiles of the processed parts, the outgoing line and the incoming line is obtained to obtain the incoming line and the outgoing line; Step three, coating an absorbent on the pre-cutting area of the silicon nitride ceramic; the absorbent comprises the following components in a mass ratio: 30% of carmine, 15% of polyvinyl alcohol, 20% of red ink and 35% of water; Step four, cutting the silicon nitride ceramic by using a laser of the laser cutting device according to the cutting path and the laser processing parameters; the laser is a carbon dioxide laser cutter; Step five, blowing away the molten material by using auxiliary gas coaxial with the light beam, and the auxiliary gas also plays a cooling role, so that a continuous cutting seam is formed on the surface of the silicon nitride ceramic; the pressure of the auxiliary gas is 0.6 MPa.

2. The method of claim 1, wherein, In step two, the laser processing parameters include switch light compensation, and micron-level precision is selected for switch light compensation.

3. The method of claim 1, wherein, In step four, the pulse laser frequency of the laser is 750 Hz.

4. The method of claim 1, wherein, In step four, the pulse laser energy of the laser is 55 w.

5. The method of claim 1, wherein, In step four, the pulse laser pulse width of the laser is 300 microseconds.

6. The method of claim 1, wherein, In step four, the laser head walking speed of the laser is 5.5 mm / s.

7. The method of claim 1, wherein, In step five, the auxiliary gas is nitrogen or air.

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