Conical surface intersecting hole machining method

Abstract

The invention relates to a conical surface intersecting hole machining method which comprises the following steps: positioning and clamping a positioning disc, and calibrating a universal angle milling head; a drill bit is installed on the universal angle milling head, tool setting is conducted, and the drill bit is positioned to the position of a workpiece hole; the drill bit is subjected to multiple times of interpolation feeding and retracting motion in the direction of the workpiece hole, and scrap iron is discharged during retracting; and after machining is completed, the drill bit retracts. By feeding and retracting a cutter back and forth during machining and discharging scrap iron during cutter retracting, the scrap iron is prevented from repeatedly scraping a hole wall, the quality defect of the hole wall is improved, the machining quality is improved, the service life of the cutter is prolonged, the machining time is shortened, and the machining cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of engine casing processing, and in particular to a method for processing conical surface intersection holes. Background Art

[0002] At present, the engine fuel injection casing is one of the important parts of the rocket engine. With the increasing demand for rocket engines, the demand for injection casing parts has also increased. The quality of the fuel injection hole of the injection casing is related to the operation of the entire engine. The narrow groove on the inner conical surface of the casing and the outer conical surface intersect at different angles, which can easily lead to quality defects in the hole wall during drilling, especially when the number of holes is large, which can easily cause unstable hole quality, fast tool wear, long processing time and high cost. Summary of the invention

[0003] Based on the above description, the present invention provides a method for processing conical intersecting holes to solve the problems of hole wall quality defects and unstable quality in the related art.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a method for processing conical intersecting holes, which includes the following steps: positioning and clamping a positioning plate, calibrating a universal angular milling head; installing a drill bit on the universal angular milling head and aligning the tool, positioning the drill bit to the workpiece hole position; performing multiple interpolation in and out movements of the drill bit along the direction of the workpiece hole, and discharging iron chips when retracting the tool; after processing is completed, retracting the drill bit.

[0005] Based on the above technical solution, the present invention can also be improved as follows.

[0006] Furthermore, the calibration of the universal angular milling head includes: manually adjusting a known angle to achieve a rough calibration of the angle; and utilizing a dial indicator and a trigonometric function relationship to achieve a fine calibration of the angle by moving the machine tool coordinates.

[0007] Furthermore, the rough calibration is based on the dial angle of the universal angular milling head; the fine calibration is based on the 100% perpendicularity of the needle to the standard inspection rod, moving the machine tool horizontally and vertically, and using the trigonometric function relationship to check the deviation of the dial indicator.

[0008] Furthermore, the step of installing the drill bit on the universal angle milling head and aligning the tool includes: aligning the drill shoulder edge with the workpiece plane, and automatically setting the tool tip point length in the Y direction using macro variables; using the tool tip point to touch the outer conical surface of the workpiece, and automatically setting the tool tip point length in the Z direction using macro variables.

[0009] Furthermore, when calibrating the plane of the workpiece, a feeler gauge is used to fill the gap and the tool is manually rotated to find the lowest point; when calibrating the outer conical surface of the workpiece, a tool with a known standard diameter is used to calibrate the gap between the tool tip and the workpiece.

[0010] Furthermore, positioning the drill bit at the workpiece hole position includes: customizing the drill bit of a fixed length, and extending it to the bottom each time it is inserted into the ER tool handle; using the tool tip to align the workpiece reference position, and using a feeler gauge to fill the gap; calculating the tool tip point deviation based on the gap using a trigonometric function relationship, and compensating it in the workpiece coordinate system.

[0011] Furthermore, the said performing multiple interpolation in-and-out movements of the drill bit along the direction of the workpiece hole comprises: when the drill bit is advanced, a stepping movement of a few millimeters is performed each time; when the drill bit is retracted, iron chips are shed by means of spindle rotation and high-pressure cutting fluid.

[0012] Furthermore, when using the drill bit for processing, two types of drill bits with different diameters are used, a drill bit with a smaller diameter is used for rough drilling, and a drill bit with a larger diameter is used for fine drilling.

[0013] Furthermore, in the interpolation movement of the drill bit along the direction of the workpiece hole, multiple step cutting, and chip removal, the tool retraction also includes: before the drill bit is connected with the inner ring groove, a short stop is made and a feed parameter is adjusted.

[0014] Furthermore, retracting the drill bit includes: keeping the drill bit at the bottom of the hole for 2 to 3 seconds and retracting the drill bit at a feed speed.

[0015] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: By moving the tool back and forth during processing and discharging iron chips when retracting the tool, the iron chips are prevented from repeatedly scraping the hole wall, the quality defects of the hole wall are improved, the processing quality is improved, the tool life is extended, the processing time is shortened, and the processing cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of the conical surface intersecting hole processing provided by an embodiment of the present invention; Figure 2 A schematic cross-sectional view of the intersection of a slot and a hole provided in an embodiment of the present invention; Figure 3 A schematic diagram of a drilling process provided by an embodiment of the present invention.

[0017] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Universal angle milling head; 2. Drill bit; 3. Uniformly distributed holes; 4. Inner ring groove; 5. M12 bolts and pressure plate; 6. Positioning plate. DETAILED DESCRIPTION

[0018] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0019] An embodiment of the present invention provides a method for processing conical intersecting holes, which can realize the processing of holes when slots with various angles intersect. At the same time, it points out its tool setting method and error elimination method, and effectively realizes the processing of drilling hundreds of holes with two drill bits at a time, and the hole wall quality meets the requirements.

[0020] Reference Figure 1 and Figure 2 , is a method for processing a conical surface intersecting hole provided by an embodiment of the present invention. It comprises the following steps: Step S1. The positioning plate 6 is quickly positioned and clamped.

[0021] Step S1.1 The positioning plate 6 is fixedly mounted on the machine tool workbench; Step S1.2: The workpiece is loaded into the positioning plate 6 with the positioning stop, and is quickly positioned and installed. The clearance between the positioning stop and the workpiece is controlled to be 0.03-0.05 mm.

[0022] Step S2: Angle calibration of the universal angular milling head 1.

[0023] Step S2.1 manually adjust the known angle to achieve rough calibration of the angle; the rough adjustment of the angle is based on the angle of the dial of the universal angular milling head 1; Step S2.2 Use the relationship between the dial indicator and trigonometric functions to achieve precise angle calibration by moving the machine tool coordinates; fine-tune the angle, with the dial indicator needle perpendicular to the standard inspection rod, move the machine tool coordinates in the horizontal and vertical directions, and use the trigonometric function relationship to check the dial indicator deviation.

[0024] Step S3: Install the drill bit 2 and the drill bit bevel tool.

[0025] Step S3.1 The shoulder edge of drill bit 2 is aligned with the workpiece plane, and the length of the tool tip in the Y direction is automatically set using macro variables; when aligning the workpiece end face, a feeler gauge can be used to prevent the workpiece surface from being scratched, and the tool should be manually rotated to find the lowest point; Step S3.2 uses the tool tip to touch the outer conical surface of the workpiece, and uses macro variables to automatically set the tool tip point length in the Z direction; when dealing with the outer conical surface, a tool with a known standard diameter can be used to measure the tool gap between the tool tip and the workpiece to prevent scratches on the workpiece.

[0026] Step S4: The drill bit 2 is accurately positioned at the tapered hole position.

[0027] Step S4.1 A drill bit 2 of a fixed length is customized, and each time it is inserted into the ER tool holder, it is inserted to the bottom to ensure the consistency of the tool length; the customized length should be the shortest length to prevent the tool holder from interfering with the workpiece and the chip removal space to ensure the rigidity of the tool overhang; Step S4.2: Use the tool tip to align the workpiece reference position and use a feeler gauge to fill the gap; Step S4.3 calculates the tool tip deviation based on the clearance using the trigonometric function relationship and compensates it to the workpiece coordinate system.

[0028] Step S5: The drill 2 performs oblique interpolation feed, performs multiple step cutting, and then retracts the drill to remove chips. Step S5.1 The drill 2 cuts obliquely, and after multiple interpolation feed and retraction movements, the workpiece hole allowance is removed; each interpolation feed amount should not be less than the chamfer length of the tool tip; Step S5.2: Move the knife back and forth, and discharge iron chips when withdrawing the knife to prevent them from scratching the hole wall; the knife should be withdrawn from the hole mouth to prevent iron chips from being repeatedly scraped against the hole wall if they are not cleaned up in time.

[0029] Step S6. Use a high-pressure water gun to assist in chip removal from the drill tip and cool the tool at the same time; the high-pressure water spray pressure of the cutting fluid gun is not less than 70 bar each time. Step S7. Before the tool is connected to the inner ring groove 4, it briefly stops and the feed parameters are adjusted to make the hole wall evenly stressed, improve the hole wall quality, and prevent the tool from vibrating due to cutting force, which may cause scratches on the hole wall; the dwell time is determined according to the rotation speed and hole diameter, and generally the tool rotates no less than 2 circles.

[0030] Step S8. The tool stays at the bottom of the hole and retracts at a high speed to ensure the quality of the hole wall; the tool stays at the bottom of the hole for 2 to 3 seconds and retracts at a high speed to prevent debris from scratching the hole wall.

[0031] The drill bit specifications in steps S3, S4, and S5 are related to the size and depth of the workpiece hole to be drilled. For example, in the example, there are 4mm and 5mm drill bits, and the 4mm drill bit is mainly used for rough drilling, and the 5mm drill bit is used for hole expansion.

[0032] Among them, the above-mentioned actions of "100% calibration of angle" and "oblique alignment of tool" and the requirement of automatically calculating deviation compensation into the machine tool coordinate system by macro variables in combination with trigonometric functions are also manifestations of work skills.

[0033] Among them, the above-mentioned "oblique interpolation feed", "multiple step cutting, tool retraction and chip removal", oblique interpolation action refers to the drill bit moving in two directions along the normal direction of the workpiece hole; "multiple step cutting" refers to the oblique movement of the drill bit with a depth of several millimeters each time; "tool retraction and chip removal" refers to the drill bit withdrawing from the hole wall, using the spindle rotation and high-pressure cutting fluid to remove the iron chips entangled on the drill bit. Figure 3 As shown, the schematic diagram of the cutting process (a rapid tool movement and positioning, b speed reduction to point the hole position, c multiple tool retractions to remove chips, d multiple tool feeds for cutting, e speed reduction before connection, f tool retraction at feed speed, g stop at the bottom of the hole).

[0034] Among them, in step S5, when the drill bit and the inner ring groove are just connected, the drill bit and the groove are at different angles, resulting in uneven cutting force on both sides of the drill bit, causing the drill bit to vibrate and chip, resulting in annular scratches on the hole wall, and failing to meet the roughness requirement of Ra1.6.

[0035] Furthermore, in step S5, a one-drill-one-expand processing method is adopted, using drill bit 2 (4mm) for rough drilling and another drill bit 2 (5mm) for fine drilling, which effectively reduces the cutting allowance and reduces tool wear when drilling more holes, thereby reducing the number of tool installation and tool calibration, and achieving the goal of completing the processing of all holes with a 5mm drill bit.

[0036] In summary, through the above-mentioned hole processing method with a conical ring groove and a hole-connected structure, 450 holes around the entire circumference can be clamped and formed at one time, and a drilling and expansion method is adopted, multiple passes, and chip removal are used for cutting. The size of the overall processed hole is stable and the hole wall finish is good.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0038] It will be appreciated that spatial relationship terms such as "under," "beneath," "below," "under," "above," "above," etc., may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It will be appreciated that, in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0039] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. The "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0040] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for machining a conical surface intersecting hole, characterized in that: It includes the following steps: Positioning and clamping the positioning plate (6) and calibrating the universal angular milling head (1); Installing the drill bit (2) on the universal angle milling head (1) and aligning the tool, positioning the drill bit (2) at the position of the workpiece hole; The drill bit (2) performs multiple interpolation in-and-out movements along the direction of the workpiece hole, and discharges iron chips when the drill bit is withdrawn; After the processing is completed, the drill bit (2) is retracted.

2. The method for machining a conical surface intersecting hole according to claim 1, characterized in that: The calibrated universal angular milling head (1) comprises: Manually adjust the known angle to achieve rough calibration of the angle; By using the dial indicator and trigonometric function relationship, the precise calibration of the angle can be achieved through the movement of the machine tool coordinates.

3. The method for machining a conical surface intersecting hole according to claim 2, characterized in that: The rough calibration is based on the dial angle of the universal angular milling head (1); The precise calibration is based on making the dial indicator needle perpendicular to the standard inspection rod, moving the coordinates of the machine tool in the horizontal and vertical directions, and using the trigonometric function relationship to check the dial indicator deviation.

4. The method for machining a conical surface intersecting hole according to claim 1, characterized in that: The step of mounting the drill bit (2) on the universal angular milling head (1) and calibrating the tool comprises: Align the cutting edge of the drill bit (2) with the workpiece plane and automatically set the length of the tool tip in the Y direction using macro variables; Use the tool tip to touch the outer cone of the workpiece, and use macro variables to automatically set the tool tip length in the Z direction.

5. The method for machining a conical surface intersecting hole according to claim 4, characterized in that: When aligning the tool to the workpiece plane, use a feeler gauge to fill the gap and manually turn the tool to find the lowest point; When aligning the outer conical surface of the workpiece, a tool with a known standard diameter is used to align the gap between the tool tip and the workpiece.

6. The method for machining a conical surface intersecting hole according to claim 1, characterized in that: Positioning the drill bit (2) at the workpiece hole position comprises: The drill bit (2) is customized with a fixed length, and each time it is inserted into the ER tool holder, it extends to the bottom; Use the tool tip to align the workpiece with the reference position, and use the feeler gauge to fill the gap; The tool tip deviation is calculated based on the clearance using trigonometric functions and compensated to the workpiece coordinate system.

7. The method for machining a conical surface intersecting hole according to claim 1, characterized in that: The step of performing multiple interpolation infeed and outfeed movements of the drill bit (2) along the direction of the workpiece hole comprises: When the drill bit (2) is cutting, it performs a stepping motion with a depth of several millimeters each time; When the drill bit (2) is retracted, iron chips are removed by means of the rotation of the spindle and high-pressure cutting fluid.

8. The method for machining a conical surface intersecting hole according to claim 1, characterized in that: When the drill bit (2) is used for processing, two types of drill bits (2) with different diameters are used, the drill bit (2) with a smaller diameter is used for rough drilling, and the drill bit (2) with a larger diameter is used for fine drilling.

9. The method for machining a conical surface intersecting hole according to claim 1, characterized in that: The step of interpolating the drill bit (2) along the direction of the workpiece hole, performing multiple step cutting, and withdrawing the tool to remove chips also includes: Before the drill bit (2) communicates with the inner ring groove (4), it stops briefly and adjusts the feed parameters.

10. The method for machining a conical surface intersecting hole according to claim 1, characterized in that: The step of retracting the drill bit (2) comprises: The drill bit (2) is kept at the bottom of the hole for 2 to 3 seconds, and the drill is retracted at a feed rate.

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