Deep hole machining process of high straightness multi-stage laser micro-hole guiding and reaming method

Abstract

The application discloses a high-linearity multi-stage laser micro-hole guiding reaming method deep hole machining process and relates to the technical field of machining, which comprises the following steps: S1, calibrating a laser deep hole machining device; S2, calibrating workpiece clamping and repeated positioning based on a three-line aiming positioning method; S3, adopting multi-stage laser machining of a small-diameter deep hole; S4, using laser small-hole guiding to perform one or more times of reaming of a high-depth-diameter ratio hole, and finally machining a large-diameter deep hole with required precision; through the multi-stage laser deep hole machining technology, the application gradually forms a small hole with high linearity, and then adopts a traditional deep hole machining method to perform one or more times of reaming operation, and through the process combining laser machining and traditional reaming technology, a deep hole with higher linearity, roundness and cylindricity can be finally obtained, and the method can not only significantly improve the machining precision of products, but also has extremely important positive influence on improving the yield of deep hole products and the economic benefits of enterprises.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a deep hole machining process using a multi-stage laser-guided micro-hole expansion method with high straightness. Background Technology

[0002] Statistics show that hole machining accounts for about one-third of all machining processes in the machinery manufacturing industry, with deep hole machining accounting for over 40% of all hole machining. The definitions of small holes, micro holes, and micro-deep holes are generally as follows: small holes have a diameter of φ0.1mm to φ3.0mm; micro holes have a diameter < φ0.1mm; and generally, deep holes are defined as holes with a depth-to-diameter ratio (depth-to-diameter ratio) > 5. Typically, micro-deep holes and extra-large deep holes are more difficult to machine than medium and small diameter deep holes, primarily because ensuring the straightness of the deep hole is challenging.

[0003] Deep hole machining employs various cutting motions: workpiece rotation and tool feed; workpiece stationary and tool rotation and feed; workpiece and tool relative rotation and tool feed; workpiece rotation and feed and tool stationary. These can be summarized into three main motion forms: (1) tool rotation; (2) workpiece rotation; and (3) simultaneous counter-rotation of the tool and workpiece. During the machining process, the drill bit is affected by different external factors in all three machining methods, leading to drill bit skewness and thus affecting the straightness error of the machining accuracy (e.g., ...). Figure 6 As shown in the diagram, in deep hole machining where the workpiece remains stationary and the tool rotates, the difference in straightness between the feed and the workpiece results in a significant deviation between the actual and ideal axes of the machined workpiece. Furthermore, the deep hole machining tool is in a semi-closed or closed state, making it necessary to rely on experience to determine if the cutting process is normal. Insufficient drill rod rigidity can lead to bending due to its own weight, vibration, and drilling force, severely impacting the hole's machining quality. Ensuring high straightness in deep hole machining with a stationary workpiece and rotating tool is an international challenge. This is particularly true for drilling with medium to large depth-to-diameter ratios, which significantly reduces drilling accuracy, leading to deviations and product scrap. Therefore, a high-straightness, multi-stage laser-guided micro-hole reaming deep hole machining process is needed to solve these problems. Summary of the Invention

[0004] The purpose of this invention is to provide a deep hole machining process using a high-straightness, multi-level laser-guided micro-hole method to solve the problems existing in the prior art as described in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A high-straightness, multi-stage laser-guided deep hole reaming process includes the following steps:

[0007] S1: Calibrate the laser deep hole machining equipment;

[0008] S2: Calibration of workpiece clamping and repeatable positioning based on the three-line aiming positioning method;

[0009] S3: Employs multi-stage laser processing for small-diameter deep holes;

[0010] S4: Using laser-guided small hole drilling, the depth-to-diameter ratio hole is increased once or multiple times, ultimately producing a large-diameter deep hole with the required precision.

[0011] Preferably, the specific steps for calibrating the laser deep hole machining equipment in S1 are as follows:

[0012] S11: The processing laser is arranged perpendicularly to the upper laser aiming device and the lower laser aiming device on the same straight line of the support. The distance between the upper laser aiming device and the lower laser aiming device is l1, and the distance between the lower laser aiming device and the processing laser is l2.

[0013] S12: Set the upper aiming point, lower aiming point and preset hole position on the target plate and align them in a straight line. The distance between the upper aiming point and the lower aiming point is l1, and the distance between the lower aiming point and the preset hole position is l2.

[0014] S13: The laser bracket and the target plate are arranged in parallel with a distance of l, which is greater than the length of the deep hole of the workpiece. The upper laser sight and the lower laser sight on the laser bracket aim at the upper aiming point and the lower aiming point on the target plate, respectively, and then the upper laser sight and the lower laser sight are fixed.

[0015] S14: Adjust the calibration function of the processing laser to align it with the preset hole position. Fix the processing laser on the laser holder. This is the initial position of the processing laser. The calibration is complete.

[0016] Preferably, the specific steps of S2 are as follows:

[0017] S21: Align the preset holes on the target plate with the preset holes on one end of the workpiece, and fix the target plate and the corresponding axes of the preset holes on the workpiece one and two perpendicular to each other.

[0018] S22: Adjust the laser bracket so that the upper and lower laser sights on the laser bracket are aimed at the upper and lower aiming points on the target plate, respectively. Activate the calibration function of the processing laser so that it is aligned with the preset hole position two on the other end of the workpiece. Then fix the laser bracket, workpiece and target plate and the clamping is complete.

[0019] S23: During the processing, the target plate and the workpiece are relatively fixed. When laser focusing may cause the processing line to deviate, in order to ensure the straightness of the processing, the laser bracket is adjusted so that the upper laser aiming device and the lower laser aiming device are re-aligned with the upper aiming point and the lower aiming point on the target plate. The processing laser will then be naturally aligned with the workpiece preset hole position one and the workpiece preset hole position two on the workpiece.

[0020] Preferably, the specific steps in S3 are as follows:

[0021] S31: A vacuum chamber is installed between the processing laser and the workpiece. The vacuum chamber is assembled with the workpiece to form a closed space through a sealing gasket. The vacuum chamber is equipped with a vacuum outlet.

[0022] S32: Adjust the focus of the processing laser so that it falls on the preset hole position two on the workpiece;

[0023] S33: Start the processing laser to drill holes. The laser ablation product generates air plasma. Due to the negative pressure of the vacuum chamber, the air plasma is discharged from the vacuum outlet, forming a small hole of a certain depth.

[0024] S34: Measure the depth of the bottom of the hole and adjust the laser focus of the processing laser so that it falls near the bottom of the hole after it has been drilled;

[0025] S35: Repeat step S33 to form a deeper two-stage hole;

[0026] S36: Repeat steps S33, S34 and S35 to form a through hole or a blind hole of a certain depth.

[0027] Preferably, the specific steps in S4 are as follows:

[0028] S41: Mount a workpiece with a small hole processed by laser onto a medium hole drilling machine.

[0029] S42: Use a gun drill to enlarge the center hole. The drill bit has a tapered cutting edge of 120° to 150° at the top. The tapered cutting edge ensures that the drill bit cuts along the direction of the small hole.

[0030] S43: Based on the small hole guide hole enlargement to obtain the middle hole, the middle hole is used as the guide hole, and the hole is enlarged again using deep hole gun drill, BTA drill, jet suction drill and DF deep hole drill, and finally the large diameter deep hole with the required precision is machined.

[0031] Preferably, the diameter of the small hole in S36 is d0≈2mm.

[0032] Preferably, in step S42, the diameter of the central hole d1 ≤ 3d0, and in step S43, the diameter of the hole further enlarged d2 ≤ 3d1.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] This invention utilizes multiple laser deep hole machining techniques to gradually form small holes with high straightness. Subsequently, traditional and widely used deep hole machining methods are employed to perform one or more hole-reaming operations. Through this process combining laser machining with traditional hole-reaming techniques, deep holes with high straightness, roundness, and cylindricity can ultimately be obtained. This method not only significantly improves the machining accuracy of products but also has a crucial positive impact on increasing the yield of deep hole products and enhancing the economic benefits of enterprises. It has a very broad application prospect in marine, aerospace, and other fields requiring large-scale mechanical processing. Attached Figure Description

[0035] Figure 1 This is a schematic diagram illustrating the principle of the three-line aiming and positioning method of the present invention.

[0036] Figure 2 This is a schematic diagram of the workpiece clamping method based on the three-line aiming positioning method of the present invention.

[0037] Figure 3 This is a process diagram of the multi-level laser-guided hole processing of the present invention.

[0038] Figure 4 This is a schematic diagram of the laser-guided hole drilling of the present invention.

[0039] Figure 5 This is a schematic diagram of the hole guide enlargement hole in the present invention.

[0040] Figure 6 This diagram illustrates the straightness of deep-hole parts obtained under different machining methods.

[0041] In the diagram: 1. Target plate; 2. Upper aiming point; 3. Lower aiming point; 4. Preset hole position; 5. Laser bracket; 6. Upper laser aiming device; 7. Lower laser aiming device; 8. Processing laser; 9. Aiming line one; 10. Aiming line two; 11. Aiming line three; 12. Workpiece; 13. Preset hole position one on the workpiece; 14. Preset hole position two on the workpiece; 15. Vacuum chamber; 16. Sealing gasket; 17. Vacuum outlet; 18. Through-workpiece guide hole; 19. Focal point one; 20. Focal point two; 21. Focal point three; 22. Air plasma. Detailed Implementation

[0042] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0043] Please see Figure 1-5 The present invention provides the following technical solutions:

[0044] A high-straightness, multi-stage laser-guided deep hole reaming process includes the following steps:

[0045] S1: Calibrate the laser deep hole machining equipment. The specific steps for calibrating the laser deep hole machining equipment are as follows:

[0046] S11: As Figure 1 As shown, the processing laser 8 is arranged perpendicularly to the upper laser aiming device 6 and the lower laser aiming device 7 on the same straight line of the support. The distance between the upper laser aiming device 6 and the lower laser aiming device 7 is l1, and the distance between the lower laser aiming device 7 and the processing laser 8 is l2. Figure 1 The aiming lines are: 9 (first), 10 (second), and 11 (third).

[0047] S12: Make a target plate 1, set an upper aiming point 2, a lower aiming point 3 and a preset hole position 4 on the target plate 1 and put them on the same straight line. The distance between the upper aiming point 2 and the lower aiming point 3 is l1, and the distance between the lower aiming point 3 and the preset hole position 4 is l2. The spacing is the same as that between the upper and lower laser aiming devices and the processing laser 8.

[0048] S13: The laser bracket 5 is arranged parallel to the target plate 1 with a spacing of l, which is greater than the length of the deep hole of the workpiece. The upper laser aiming device 6 and the lower laser aiming device 7 on the laser bracket 5 aim at the upper aiming point 2 and the lower aiming point 3 on the target plate 1, respectively, and then the upper laser aiming device 6 and the lower laser aiming device 7 are fixed.

[0049] S14: Adjust the calibration function of the processing laser 8 to align it with the preset hole position 4. Fix the processing laser 8 on the laser bracket 5. This is the initial position of the processing laser 8. The calibration is complete.

[0050] S2: Based on the three-line aiming positioning method, workpiece clamping and repeated positioning are calibrated. During multiple laser deep hole drilling processes, workpiece clamping based on laser calibration is crucial for ensuring high straightness control. The specific steps are as follows:

[0051] S21: As Figure 2 As shown, the preset hole 4 on the target plate 1 is aligned with the preset hole 13 at one end of the workpiece 12, so that the corresponding axes of the preset hole 13 and the preset hole 14 on the target plate 1 and the workpiece 12 are perpendicularly fixed.

[0052] S22: Adjust the laser bracket 5 so that the upper laser sight 6 and the lower laser sight 7 on the laser bracket 5 aim at the upper aiming point 2 and the lower aiming point 3 on the target plate 1 respectively. Start the calibration function of the processing laser 8 so that it is aligned with the workpiece preset hole position 14 on the other end of the workpiece 12. Then fix the laser bracket 5, the workpiece 12 and the target plate 1. The clamping is complete.

[0053] S23: During the processing, the target plate 1 and the workpiece 12 are relatively fixed. When laser focusing may cause the processing line to deviate, in order to ensure the straightness of the processing, the laser bracket 5 is adjusted so that the upper laser aiming device 6 and the lower laser aiming device 7 are re-aligned with the upper aiming point 2 and the lower aiming point 3 on the target plate 1. The processing laser 8 is then naturally aligned with the workpiece preset hole position 13 and the workpiece preset hole position 24 on the workpiece 12, restoring the initial position and ensuring the straightness accuracy of the processing.

[0054] S3: Multi-stage laser processing is used to process small-diameter deep holes. The specific steps are as follows:

[0055] S31: As Figure 3 (1) As shown in the figure, a vacuum chamber 15 is installed between the processing laser 8 and the workpiece 12. The vacuum chamber 15 is assembled with the workpiece 12 through the sealing gasket 16 to form a closed space. The vacuum chamber 15 is provided with a vacuum outlet 17.

[0056] S32: As Figure 3 As shown in (1), adjust the focus of the processing laser 8 so that it falls on the preset hole position 14 of the workpiece;

[0057] S33: Adjust the processing laser 8 to the high-power drilling setting, start the processing laser 8 to drill, the laser ablation product generates air plasma 22, due to the negative pressure of the vacuum chamber 15, the air plasma 22 is discharged from the vacuum outlet 17, such as Figure 3 (2) As shown, a small hole of a certain depth is made;

[0058] S34: Measure the depth of the bottom of the small hole, adjust the laser focus of the processing laser 8 so that it falls near the bottom of the hole just after it was drilled, such as focus 1 (19), focus 2 (20), and focus 3 (21). Figure 3 As shown in (1), (3), and (5);

[0059] S35: Repeat step S33 to form a deeper two-stage aperture, such as Figure 3 (4) and Figure 3 (5) is shown;

[0060] S36: Repeat steps S33, S34, and S35 to form a through hole with a diameter d0 ≈ 2 mm, such as Figure 3 As shown in (6), the through-workpiece guide hole 18 is formed by laser processing. The hole has high straightness, but the surface finish and roundness are very low.

[0061] S4: Using laser-guided pinhole drilling to increase the aspect ratio of the hole in one or more steps, the specific steps are as follows:

[0062] S41: Mount a workpiece with a small hole processed by laser onto a medium hole drilling machine.

[0063] S42: Use a gun drill to enlarge the center hole. The diameter of the center hole is d1≤3d0. The top of the drill bit has a tapered cutting edge of 120°~150°. The tapered cutting edge ensures that the drill bit cuts along the direction of the small hole.

[0064] S43: Based on the small hole guide hole enlargement to obtain the middle hole, the middle hole is used as the guide hole, and the hole is enlarged again using deep hole gun drill, BTA drill, jet suction drill and DF deep hole drill, etc. The diameter of the second enlargement hole d2≤3d1, and finally the large diameter deep hole with the required accuracy is machined.

[0065] A small-diameter guide hole is used to ream the hole to obtain a medium-diameter hole. This medium-diameter hole is then used as a guide hole to ream the hole to a larger diameter deep hole. The diameter variation of the reaming drill bit must be controlled within d. m ≤3d m-1 In other words, the diameter of the reamer should not exceed three times the diameter of the guide hole; otherwise, the short-board effect will not occur, the weak link will not be obvious, and the small hole guide hole effect will be poor. In addition, the reamer bit should have a tapered cutting edge of 120° to 150° at the top and have an automatic hole-finding drilling function.

[0066] The benefits of deep hole machining are mainly reflected in the yield rate, which is exponentially negatively correlated with the depth-to-diameter ratio. According to incomplete statistics, when the hole depth exceeds 2 meters, the yield rate can reach 80%, meaning a scrap rate of approximately 20%. For components requiring deep hole machining alone, the cost ranges from tens of thousands to hundreds of thousands of yuan. This high cost is closely related to the high scrap rate of drilling with large depth-to-diameter ratios; if even one hole is unusable, the entire part becomes unusable. The multi-stage laser micro-hole guided reaming deep hole machining process proposed in this invention ensures the straightness of the hole through multi-stage laser processing, followed by reaming using conventional drilling techniques to guarantee machining accuracy and quality. This process significantly improves the yield rate of deep hole machining, reducing the scrap rate to below 3%, and theoretically even achieving a zero scrap rate. Therefore, this process can significantly reduce processing costs, improve the economic benefits of enterprises, and enhance the market competitiveness of products.

[0067] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A deep hole machining process using a multi-stage laser-guided micro-hole method with high straightness, characterized in that, Includes the following steps: S1: Calibrate the laser deep hole machining equipment; the specific steps for calibrating the laser deep hole machining equipment in S1 are as follows: S11: Arrange the processing laser (8) perpendicularly to the upper laser sight (6) and the lower laser sight (7) on the same straight line of the support, with the distance between the upper laser sight (6) and the lower laser sight (7) being... The distance between the lower laser sight (7) and the processing laser (8) is ; S12: Set the upper aiming point (2), lower aiming point (3), and preset hole position (4) on the target plate (1) and align them on the same straight line. The distance between the upper aiming point (2) and the lower aiming point (3) is... The distance between the lower aiming point (3) and the preset hole position (4) is ; S13: The laser support (5) and the target plate (1) are arranged in parallel, with a spacing of [missing information]. l , l The length of the deep hole is greater than that of the workpiece, so that the upper laser sight (6) and the lower laser sight (7) on the laser bracket (5) aim at the upper aiming point (2) and the lower aiming point (3) on the target plate (1) respectively, and then the upper laser sight (6) and the lower laser sight (7) are fixed. S14: Adjust the calibration function of the processing laser (8) to align it with the preset hole position (4), and fix the processing laser (8) on the laser bracket (5). This is the initial position of the processing laser (8). The calibration is complete. S2: Calibrate workpiece clamping and repeat positioning based on the three-line aiming positioning method; the specific steps of S2 are as follows: S21: Align the preset hole (4) on the target plate (1) with the preset hole (13) on one end of the workpiece (12), so that the corresponding axes of the preset hole (13) and the preset hole (14) on the target plate (1) and the workpiece (12) are perpendicular and fixed. S3: Multi-stage laser processing is used to process small-diameter deep holes; the specific steps in S3 are as follows: S31: A vacuum chamber (15) is installed between the processing laser (8) and the workpiece (12). The vacuum chamber (15) is assembled with the workpiece (12) through a sealing gasket (16) to form a closed space. The vacuum chamber (15) is provided with a vacuum outlet (17). S32: Adjust the focus of the processing laser (8) so that it falls on the preset hole position two (14) of the workpiece; S33: Start the processing laser (8) to drill holes. The laser ablation product generates air plasma (22). Due to the negative pressure of the vacuum chamber (15), the air plasma (22) is discharged from the vacuum outlet (17) and forms a small hole of a certain depth. S34: Measure the depth of the bottom of the hole and adjust the laser focus of the processing laser (8) so that it falls near the bottom of the hole after it has been drilled; S35: Repeat step S33 to form a deeper two-stage hole; S36: Repeat steps S33, S34 and S35 to form a through hole or a blind hole of a certain depth. S4: Using laser-guided small hole drilling, the depth-to-diameter ratio hole is increased once or multiple times, ultimately producing a large-diameter deep hole with the required precision.

2. The deep hole machining process using a multi-stage laser-guided micro-hole method with high straightness according to claim 1, characterized in that, The specific steps of S2 also include: S22: Adjust the laser bracket (5) so that the upper laser sight (6) and lower laser sight (7) on the laser bracket (5) aim at the upper aiming point (2) and lower aiming point (3) on the target plate (1) respectively. Start the calibration function of the processing laser (8) so that it is aligned with the workpiece preset hole position two (14) on the other end of the workpiece (12). Then fix the laser bracket (5), workpiece (12) and target plate (1) and the clamping is completed. S23: During the processing, the target plate (1) and the workpiece (12) are relatively fixed. When laser focusing may cause the processing line to deviate, in order to ensure the straightness of the processing, the laser bracket (5) is adjusted so that the upper laser aiming device (6) and the lower laser aiming device (7) are re-aligned with the upper aiming point (2) and the lower aiming point (3) on the target plate (1). The processing laser (8) is then naturally aligned with the workpiece preset hole position one (13) and the workpiece preset hole position two (14) on the workpiece (12).

3. The deep hole machining process using a multi-stage laser-guided micro-aperture method with high straightness according to claim 1, characterized in that, The specific steps in S4 are as follows: S41: Mount the workpiece with laser-machined small holes onto a medium hole drilling machine. S42: Use a gun drill to enlarge the center hole. The drill bit has a tapered cutting edge of 120° to 150° at the top. The tapered cutting edge ensures that the drill bit cuts along the direction of the small hole. S43: Based on the small hole guide hole enlargement to obtain the middle hole, the middle hole is used as the guide hole, and the hole is enlarged again using deep hole gun drill, BTA drill, jet suction drill and DF deep hole drill, and finally the large diameter deep hole with the required precision is machined.

4. The deep hole machining process using a multi-stage laser-guided micro-hole method with high straightness according to claim 1, characterized in that, The diameter of the small hole in S36 .

5. The deep hole machining process using a multi-stage laser-guided micro-hole method with high straightness according to claim 3, characterized in that, In S42, the diameter of the central hole In step S43, the diameter of the hole is enlarged again. .

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