Machining method of nozzle oil hole

Abstract

The invention discloses a processing method of a nozzle oil hole, which is used for processing the nozzle oil hole on an aluminum magnesium alloy casing, the nozzle oil hole is a discontinuous deep small hole, the hole depth is 30mm, the length of the front half section is 14mm, the length of the discontinuous part is 8mm-10mm, the hole diameter is 0.5 mm-0. 8mm, the tolerance of the hole diameter is within + / -0.05 mm, and the length-diameter ratio is greater than 37.5. The machining method comprises the following machining steps that S1, a first drill bit with the cutting edge length being 15 mm and a second drill bit with the cutting edge length being 32 mm are designed and manufactured, the drill tip angle of the second drill bit ranges from 145 degrees to 150 degrees, and the spiral angle ranges from 20 degrees to 25 degrees; s2, a centering hole with the depth being 0.2 mm is machined through a three-blade drill bit with the diameter phi being 5 mm; s3, the first drill bit is used for machining the front half section of the nozzle oil hole; s4, the second drill bit is used for machining the rear half section of the nozzle oil hole; compared with the prior art, the tool is low in manufacturing difficulty, smooth in chip removal, not prone to breakage and high in drilling and milling efficiency, the problems of electrode arcing, electrode outward inclination and the like in an electric machining method cannot occur, and the tool is suitable for wide application and popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine hole machining, and in particular to a method for machining a nozzle oil hole. Background Art

[0002] The aluminum-magnesium alloy casing of an aircraft engine is provided with a nozzle oil hole. The nozzle oil hole is a discontinuous deep small hole with a hole diameter between 0.5-0.8mm, a hole diameter tolerance within ±0.05mm, and an aspect ratio greater than 37.5. The nozzle oil hole is connected to the oil circuit inside the casing. However, in the actual processing process, due to the large aspect ratio of the deep hole, it is necessary to use a gun drill on a dedicated equipment for processing. However, due to the limitations of the gun drill itself, it is difficult to manufacture a size below φ3mm. The chip removal is affected by factors such as the smaller chip space, the limited internal cooling structure, the reduced tool rigidity, the reduced cutting line speed and the increased resistance. The smaller the aperture, the more difficult it is to remove chips. In the case of poor chip removal, the tool is very likely to break. In addition, aluminum-magnesium alloy materials are soft and easy to cut, but during the cutting process, chip debris easily sticks to the tool to form blocks, exacerbating the poor chip removal. Since the discontinuity of the nozzle oil hole is the rough surface, ordinary drilling and milling processing usually requires the use of buried drills or milling cutters to smooth the rough pieces before subsequent drilling. However, the hole needs to be designed with a φ0.8mm buried drill or milling cutter that is more than 20mm long. It is difficult to manufacture and has weak rigidity. In the subsequent burying or milling process, the tool will be subjected to radial and axial forces at the same time and is prone to breakage.

[0003] If the nozzle oil hole adopts the electro-corrosion processing technology, by using an electrode with a diameter of 0.65mm, electro-corrosion processing is gradually carried out under a given voltage and current. However, due to the high processing precision and deep hole of the nozzle oil hole, cooling kerosene is not easy to enter the hole, resulting in electrode arcing and electrode outward tilting. After the electrode arcs, the reheating layer of the hole wall will be aggravated, resulting in the metallographic structure of the material not meeting the requirements. The outward tilt of the electrode will cause the position of the hole to deviate, and the round hole will be processed into a non-round hole, resulting in dimensional deviation. Therefore, after a period of processing, it is necessary to check the electrode position and straightness to replace or correct the electrode. The operation process is cumbersome and complicated. In addition, it takes 4-6 hours to electro-corrode the hole in the actual processing process, and the processing efficiency is extremely low.

[0004] It should be noted that the disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0005] The present invention provides a method for processing nozzle oil holes to solve the technical problems of difficulty in manufacturing tools, poor chip removal and easy breakage of tools during drilling and milling of nozzle oil holes on existing aluminum-magnesium alloy casings, as well as electrode arcing, electrode outward tilting and extremely low processing efficiency during electro-corrosion processing.

[0006] According to one aspect of the present invention, a method for processing a nozzle oil hole is provided, which is used for processing a nozzle oil hole on an aluminum-magnesium alloy casing, wherein the nozzle oil hole is an intermittent deep small hole with a hole depth of 30 mm, a front half length of 14 mm, a discontinuity length of 8 mm-10 mm, a hole diameter between 0.5 mm and 0.8 mm, a hole diameter tolerance within ±0.05 mm, and an aspect ratio greater than 37.5. The processing method includes the following processing steps: S1: designing and manufacturing a first drill bit with a cutting edge length of 15 mm and a second drill bit with a cutting edge length of 32 mm, and the drill tip angle of the second drill bit is 145°-150°, and the helix angle is 20°-25°; S2: using a φ5 mm three-edge drill bit to process a centering hole with a depth of 0.2 mm; S3: using the first drill bit to process the front half of the nozzle oil hole; S4: using the second drill bit to process the back half of the nozzle oil hole.

[0007] As a further improvement of the above technical solution:

[0008] Furthermore, the cutting edge diameter of the first drill bit is 0.825 mm-0.830 mm, and the cutting edge diameter of the second drill bit is 0.770 mm-0.775 mm.

[0009] Furthermore, after the first drill bit and the second drill bit are clamped, the runout of the polished rod portion does not exceed 0.005 mm.

[0010] Furthermore, step S3 specifically includes the following processing steps: S31: using the first rotation speed, the first feed speed and the G81 drilling cycle to drill to a depth of 3 mm; S32: using the second rotation speed, the second feed speed and the G83 drilling cycle to drill to a depth of 13.5 mm, wherein the second drilling speed is greater than the first drilling speed, and the second feed speed is greater than the first feed speed; S33: using the first rotation speed, the first feed speed and G81 to drill through the front half of the nozzle oil hole; S34: using the first rotation speed and the first feed speed to retract the drill.

[0011] Further, step S4 specifically includes the following steps: S41: using the first speed and the first feed speed to enter the front half of the nozzle oil hole; S42: using the first speed and the second feed speed to pass through the front half of the nozzle hole until it is 2 mm away from the rear half of the nozzle hole; S43: using the first speed, the first feed speed and the G81 drilling cycle to drill the centering hole; S44: using the second speed, the second feed speed and the G83 drilling cycle to drill to a depth of 39.5 mm; S45: using the first speed, the first feed speed and G81 to drill through the rear half of the nozzle oil hole; S46: using the first speed and the first feed speed to retract the drill.

[0012] Furthermore, step S41 further includes step: S40, applying lubricating oil on the second drill bit.

[0013] Furthermore, step S44 also includes the step of injecting coolant into the oil hole of the nozzle.

[0014] Furthermore, the first rotational speed is 3000r-4000r / min, the first feed speed is 0.5mm / min, the second rotational speed is 6000r-10000r / min, and the second feed speed is 100mm / min.

[0015] Furthermore, the exit plane of G83 is set within the hole depth of 3mm of the nozzle oil hole, and a pause of 2s is made after each exit.

[0016] Furthermore, the pecking depth of G83 is 0.1mm-0.2mm.

[0017] The present invention has the following beneficial effects:

[0018] The processing method of the nozzle oil hole of the present invention first designs and manufactures a first drill bit with a cutting edge length of 15 mm and a second drill bit with a cutting edge length of 32 mm, and the drill tip angle of the second drill bit is 145°-150°, and the helix angle is 20°-25°, and then a φ5mm three-edge drill bit is used to process a centering hole with a depth of 0.2 mm, and then the first drill bit is used to process the front half of the nozzle oil hole, and finally the second drill bit is used to process the back half of the nozzle oil hole; when the second drill bit processes the back half of the nozzle oil hole, since the entrance part of the back half is the blank surface, the surface quality is poor, and it is not at a right angle of 90° to the drill bit direction, by making the drill tip angle of the second drill bit 145°-150°, the outer edge of the drill tip is first brought into contact with the blank surface, and since the linear speed of the outer edge is high and the cutting force is small, the centering stability of the second drill bit is improved , the anti-deflection ability is improved, which is conducive to the processing of the centering hole, and the cutting edge of the second drill bit is made thick, which improves the bending resistance of the second drill bit and prevents the second drill bit from breaking; at the same time, due to insufficient cooling and lubrication during the processing of the second half of the hole, the helix angle of the second drill bit is set to 20°-25° to improve the chip removal ability of the second drill bit, thereby improving the anti-blocking ability and ensuring smooth chip removal; this solution adopts a three-edged drill bit, a first drill bit and a second drill bit for processing in sequence to reduce the manufacturing difficulty of the tool, and by improving the structure of the second drill bit, a second drill bit is used to complete the processing of the centering hole and the second half of the hole in sequence. Compared with the existing technology, the manufacturing difficulty of the tool is low, the chip removal is smooth, the tool is not easy to break, and the efficiency of drilling and milling is high. There will be no problems such as electrode arcing and electrode outward tilt in the electrical machining method. It is highly practical and suitable for wide promotion and application.

[0019] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 It is a flowchart of the steps of the method for processing the nozzle oil hole according to the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0023] like Figure 1As shown, the processing method of the nozzle oil hole of the present embodiment is used to process the nozzle oil hole on the aluminum-magnesium alloy casing, wherein the nozzle oil hole is an intermittent deep small hole with a hole depth of 30 mm, a front half length of 14 mm, a discontinuity length of 8 mm-10 mm, a hole diameter between 0.5 mm and 0.8 mm, a hole diameter tolerance within ±0.05 mm, and an aspect ratio greater than 37.5. The processing method includes the following processing steps: S1: designing and manufacturing a first drill bit with a cutting edge length of 15 mm and a second drill bit with a cutting edge length of 32 mm, and the drill tip angle of the second drill bit is 145°-150°, and the helix angle is 20°-25°; S2: using a φ5 mm three-edge drill bit to process a centering hole with a depth of 0.2 mm; S3: using the first drill bit to process the front half of the nozzle oil hole; S4: using the second drill bit to process the back half of the nozzle oil hole.

[0024] like Figure 1 As shown, specifically, the method for processing the nozzle oil hole of the present invention is to first design and manufacture a first drill bit with a cutting edge length of 15 mm and a second drill bit with a cutting edge length of 32 mm, and the drill tip angle of the second drill bit is 145°-150°, and the helix angle is 20°-25°, and then use a φ5mm three-edge drill bit to process a centering hole with a depth of 0.2 mm, and then use the first drill bit to process the front half of the nozzle oil hole, and finally use the second drill bit to process the back half of the nozzle oil hole; when the second drill bit processes the back half of the nozzle oil hole, since the entrance part of the back half is the blank surface, the surface quality is poor, and it is not at a 90° right angle to the drill bit direction, by making the drill tip angle of the second drill bit 145°-150°, the outer edge of the drill tip is first brought into contact with the blank surface, and since the linear speed of the outer edge is high and the cutting force is small, the centering of the second drill bit is stable. The qualitative improvement and anti-deflection ability are improved, which is conducive to the processing of the centering hole, and the cutting edge of the second drill bit is made thick, which improves the bending resistance of the second drill bit and prevents the second drill bit from breaking; at the same time, due to insufficient cooling and lubrication during the processing of the second half of the hole, the helix angle of the second drill bit is set to 20°-25° to improve the chip removal ability of the second drill bit, thereby improving the anti-blocking ability and ensuring smooth chip removal; this solution adopts a three-edged drill bit, a first drill bit and a second drill bit for processing in sequence to reduce the manufacturing difficulty of the tool, and by improving the structure of the second drill bit, a second drill bit is used to complete the processing of the centering hole and the second half of the hole in sequence. Compared with the existing technology, the manufacturing difficulty of the tool is low, the chip removal is smooth, the tool is not easy to break, and the efficiency of drilling and milling is high. There will be no problems such as electrode arcing and electrode outward tilt in the electrical machining method. It is highly practical and suitable for wide promotion and application. Optionally, the shank diameter of the first drill bit and the second drill bit is 5 mm, a conical transition is used between the shank and the cutting edge, the tool material is high-speed steel, and the surface is heat treated to improve the wear resistance of the cutting edge.

[0025] It should be understood that the angle of the drill tip of a conventional drill bit is 118° and the helix angle is 35°.

[0026] Preferably, the angle of the drill tip of the second drill bit is increased from 118° to 145°, the axial cutting resistance is reduced by 30%, and the anti-deflection ability of the drill bit is increased by 3 times, realizing stable processing of the centering hole on the blank surface, and the positioning accuracy is controlled within 0.1mm.

[0027] Preferably, the helix angle of the second drill bit is reduced from 35° to 25°, and the anti-blocking capability is improved by 50%, ensuring smooth chip removal.

[0028] In this embodiment, the cutting edge diameter of the first drill bit is 0.825mm-0.830mm, and the cutting edge diameter of the second drill bit is 0.770mm-0.775mm. Specifically, the first drill bit processes the front half of the nozzle oil hole, and the second drill bit processes the back half of the nozzle oil hole. The cutting edge diameter of the first drill bit is larger than the cutting edge diameter of the second drill bit, so as to improve the rigidity of the first drill bit and improve the processing efficiency of the front half of the nozzle oil hole. The rigidity of the second drill bit is reduced, but the toughness is improved, which promotes the processing of the deep hole in the back half of the nozzle oil hole. After the first drill bit is processed, the diameter of the front half of the hole can be made larger than the diameter of the second drill bit, so that there is a certain gap between the front half of the hole and the second drill bit. This gap can reduce the risk of the second drill bit being subjected to cutting force, vibration caused by high speed, and the risk of breaking due to friction between the swing and the hole wall during processing. On the other hand, it can also play a certain corrective and supporting role for the second drill bit.

[0029] In this embodiment, the runout of the polished rod of both the first and second drill bits after clamping is no more than 0.005mm. Specifically, during nozzle oil hole machining, to avoid part interference, the tool overhang requires at least 385mm. Therefore, after the first or second drill bit is clamped, the runout of the polished rod is ensured to be no more than 0.005mm, ensuring stable operation during high-speed rotation.

[0030] In this embodiment, step S3 specifically includes the following processing steps: S31: using the first rotation speed, the first feed speed and the G81 drilling cycle to drill to a depth of 3 mm; S32: using the second rotation speed, the second feed speed and the G83 drilling cycle to drill to a depth of 13.5 mm, wherein the second drilling speed is greater than the first drilling speed, and the second feed speed is greater than the first feed speed; S33: using the first rotation speed, the first feed speed and G81 to drill through the front half of the nozzle oil hole; S34: using the first rotation speed and the first feed speed to retract the drill.

[0031] Specifically, since the second drilling speed is greater than the first drilling speed, the second feed speed is greater than the first feed speed, that is, the first drilling speed is a low rotation speed, the second drilling speed is a high rotation speed, the first feed speed is a slow feed, and the second feed speed is a fast feed, when the first rotation speed, the first feed speed and the G81 drilling cycle are used to drill a depth of 3mm, the low rotation speed and slow feed are used to avoid the first drill bit from swinging and causing a large error in hole positioning, so that the first drill bit coincides with the centering hole, so as to achieve precise guidance for subsequent hole processing; When using the second speed, the second feed rate and the G83 drilling cycle to drill a depth of 13.5mm, high speed and fast feed are used to improve the processing efficiency of the first half of the hole; when using the first speed, the first feed rate and G81 to drill through the first half of the nozzle oil hole, since the outlet of the last hole drilled in the first half is the rough surface, low speed and low feed are used to avoid uneven force and breakage of the first drill bit; when using the first speed and the first feed rate to retract the drill, low speed and low feed are used to ensure stable retraction of the first drill bit.

[0032] It should be understood that G81 and G83 are fixed cycle instructions for drilling in the CNC machining process. The characteristics of G81 are continuous drilling without chip removal, and it is suitable for shallow hole machining. The characteristics of G83 are intermittent drilling with forced chip removal, and it is suitable for deep hole machining. G81 and G83 are both well-known instructions to those skilled in the art.

[0033] It should be understood that when the first drill bit is machining the front half of the nozzle oil hole, the combined use of G81 and G83 can improve machining efficiency and chip removal effects.

[0034] In this embodiment, step S4 specifically includes the following steps: S41: using the first speed and the first feed speed to enter the front half of the nozzle oil hole; S42: using the first speed and the second feed speed to pass through the front half of the nozzle hole until it is 2 mm away from the rear half of the nozzle hole; S43: using the first speed, the first feed speed and the G81 drilling cycle to drill the centering hole; S44: using the second speed, the second feed speed and the G83 drilling cycle to drill to a depth of 39.5 mm; S45: using the first speed, the first feed speed and G81 to drill through the rear half of the nozzle oil hole; S46: using the first speed and the first feed speed to retract the drill.

[0035] Specifically, the first drilling speed is a low rotation speed, the second drilling speed is a high drilling speed, the first feed speed is a slow feed, and the second feed speed is a fast feed, so that when using the first rotation speed and the first feed speed to enter the front half of the orifice of the nozzle oil hole, the second drill bit and the front half of the orifice are accurately aligned through the low rotation speed and slow feed; when using the first rotation speed and the second feed speed to pass through the front half of the nozzle hole until it is 2mm away from the rear half of the nozzle hole, the second drill bit movement speed is increased through the low rotation speed and fast feed, thereby improving the processing efficiency; when: using the first rotation speed, the first feed speed and the G81 drilling cycle to drill the centering hole, due to The entrance of the second half of the hole is the rough surface, and low speed and low feed are used to improve the centering stability to ensure accurate drilling positioning; when using the second speed, the second feed speed and the G83 drilling cycle to drill a depth of 39.5mm, high speed and high feed are used to improve the processing efficiency of the second half of the hole; when using the first speed, the first feed speed and G81 to drill through the second half of the nozzle oil hole, since the exit of the last hole drilled in the second half is the rough surface, low speed and low feed are used to avoid uneven force and breakage of the second drill bit; when using the first speed and the first feed speed to retract the drill, low speed and low feed are used to ensure stable retraction of the second drill bit.

[0036] It should be understood that when the second drill bit is used to process the second half of the nozzle oil hole, the combined use of G81 and G83 can improve the processing efficiency and chip removal effect.

[0037] Optionally, in step S43, the cutting condition of the second drill bit may be determined by observing the power change of the spindle on the processing equipment.

[0038] In this embodiment, step S41 further includes step S40 of applying lubricating oil to the second drill bit. Specifically, since coolant has difficulty reaching the front portion of the drill bit during the machining of the rear half of the nozzle oil hole, lubricating oil is applied to the second drill bit before machining to provide cooling and lubrication, thereby reducing the risk of breakage of the second drill bit during machining.

[0039] In this embodiment, step S44 further includes the step of injecting coolant into the nozzle oil hole. Specifically, while the second half of the nozzle oil hole is being machined, the coolant is injected into the nozzle oil hole so that the coolant can reach the second drill bit processing area and carry away the cutting chips, thereby improving chip removal efficiency and reducing the risk of chip blockage.

[0040] In this embodiment, the first rotational speed is 3000r-4000r / min, the first feed speed is 0.5mm / min, the second rotational speed is 6000r-10000r / min, and the second feed speed is 100mm / min. Specifically, when the first rotating speed is 3000r / min-4000r / min, the cutting force of the drill bit is relatively balanced, the vibration is small, the cutting linear speed of the drill bit is appropriate, and the cutting force is small; when the first rotating speed is less than 3000r / min, the cutting linear speed is small and the cutting force is large; when the first rotating speed is greater than 4000r / min, the cutting force of the drill bit is unbalanced, which can easily amplify the vibration of the drill bit; when the second rotating speed is 6000r / min-10000r / min, the radial cutting force of the drill bit decreases, which will reduce the cutting resistance with the hole wall and reversely improve the torsional resistance of the drill bit, thereby improving the anti-breakage performance of the drill bit; by setting the first feed speed to 0.5mm / min, the processing stability is improved through low feed; by setting the second feed speed to 100mm / min, the processing efficiency is improved through high feed.

[0041] In this embodiment, the G83 exit plane is set within the nozzle oil hole depth of 3mm, and a 2s pause is maintained after each exit. Specifically, in steps S32 and S44, the G83 drilling cycle is used. By setting the G83 exit plane within the nozzle oil hole depth of 3mm and pausing for 2s after each exit, the first or second drill bit is prevented from completely exiting the hole, thereby ensuring machining quality.

[0042] It should be understood that if the first drill bit or the second drill bit completely exits the hole, since steps S32 and S44 are both cutting stages and high-speed processing, a certain amount of cutting debris will remain on the first drill bit or the second drill bit. At high speeds, a slight imbalance may cause the first drill bit or the second drill bit to swing, causing the hole to be damaged when the first drill bit or the second drill bit re-enters the hole, thereby reducing the processing quality.

[0043] In this embodiment, the G83 drilling depth is 0.1mm-0.2mm. Specifically, in steps S32 and S44, the G83 drilling cycle is used, and both steps S32 and S44 are cutting stages, generating a large amount of cutting debris. When the G83 drilling depth is 0.1mm-0.2mm, the processing efficiency is high and the chip removal effect is good. However, when the G83 drilling depth is less than 0.1mm, the processing efficiency is low. When the G83 drilling depth is greater than 0.2mm, the chip removal efficiency is poor, and the tool breakage is easily caused by poor chip removal.

[0044] In one embodiment, the nozzle oil hole is an intermittent deep small hole with a hole depth of 30 mm, a front half length of 14 mm, a discontinuity length of 8 mm-10 mm, a hole diameter of 0.8±0.04 mm, and an aspect ratio of 37.5. The above-mentioned nozzle oil hole processing method is used for processing, and the qualified rate reaches 100%. The single hole processing time is 35 minutes, which improves the processing efficiency by 7-8 times compared with electro-corrosion processing.

[0045] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0046] Unless otherwise defined, technical or scientific terms used in this application should have the ordinary meanings understood by persons of ordinary skill in the art to which this disclosure belongs. The terms "first," "second," and similar expressions used in this application do not denote any order, quantity, or importance, but are simply used to distinguish different components. Similarly, terms such as "a," "an," or "the" do not denote a limitation of quantity, but rather denote the presence of at least one.

[0047] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0048] This article uses specific examples to illustrate the principles and implementation methods of this application. The above examples are only used to help understand the method and core ideas of this application. The above is only the preferred implementation method of this application. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principles of this application, they can make several improvements, modifications or changes, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of this application to other occasions without improvement, should be regarded as the protection of this application.

Claims

1. A method for machining a nozzle oil hole, for machining a nozzle oil hole on an aluminum-magnesium alloy casing, wherein: The nozzle oil hole is a discontinuous deep small hole with a hole depth of 30 mm, a front half length of 14 mm, a discontinuity length of 8 mm-10 mm, a hole diameter between 0.5 mm and 0.8 mm, a hole diameter tolerance within ±0.05 mm, and an aspect ratio greater than 37.

5. The processing method includes the following processing steps: S1: Design and manufacture a first drill bit with a cutting edge length of 15 mm and a second drill bit with a cutting edge length of 32 mm, wherein the drill tip angle of the second drill bit is 145°-150° and the helix angle is 20°-25°; S2: Use a φ5mm three-edge drill bit to machine a centering hole with a depth of 0.2mm; S3: Use the first drill bit to machine the front half of the nozzle oil hole; S4: Use the second drill bit to machine the rear half of the nozzle oil hole.

2. The method for processing the nozzle oil hole according to claim 1, characterized in that: The cutting edge diameter of the first drill bit is 0.825mm-0.830mm, and the cutting edge diameter of the second drill bit is 0.770mm-0.775mm.

3. The method for machining the nozzle oil hole according to claim 1, characterized in that: After the first drill bit and the second drill bit are clamped, the runout of the polished rod part does not exceed 0.005mm.

4. The method for machining a nozzle oil hole according to any one of claims 1 to 3, characterized in that: Step S3 specifically includes the following processing steps: S31: Drill depth 3mm using the first speed, first feed rate and G81 drilling cycle; S32: Drilling to a depth of 13.5 mm using the second rotational speed, the second feed rate, and the G83 drilling cycle, wherein the second drilling speed is greater than the first drilling speed, and the second feed rate is greater than the first feed rate; S33: Drilling the front half of the nozzle oil hole using the first speed, the first feed rate, and G81; S34: retract the drill using the first rotation speed and the first feed speed.

5. The method for machining the nozzle oil hole according to claim 4, characterized in that: Step S4 specifically includes the following steps: S41: Entering the front half of the nozzle oil hole using a first rotation speed and a first feed speed; S42: using the first rotation speed and the second feed speed to pass through the front half of the nozzle hole until it is 2 mm away from the rear half end of the nozzle hole; S43: Drilling the center hole using the first speed, first feed rate and G81 drilling cycle; S44: Use the second speed, second feed rate and G83 drilling cycle to drill to a depth of 39.5 mm; S45: Drill through the rear half of the nozzle oil hole using the first speed, first feed rate, and G81; S46: retract the drill using the first rotation speed and the first feed speed.

6. The method for machining the nozzle oil hole according to claim 5, characterized in that: Step S41 also includes the following steps: S40, apply lubricating oil to the second drill bit.

7. The method for machining the nozzle oil hole according to claim 5, characterized in that: Step S44 also includes the step of injecting coolant into the oil hole of the nozzle.

8. The method for machining the nozzle oil hole according to claim 5, characterized in that: The first rotation speed is 3000r-4000r / min, the first feed speed is 0.5mm / min, the second rotation speed is 6000r-10000r / min, and the second feed speed is 100mm / min.

9. The method for machining the nozzle oil hole according to claim 5, characterized in that: The exit plane of G83 is set within 3mm of the nozzle oil hole depth, and pauses for 2s after each exit.

10. The method for machining the nozzle oil hole according to claim 5, characterized in that: The pecking depth of G83 is 0.1mm-0.2mm.

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