Method for machining ring groove of radial expansion machine case

Abstract

The machining method of the ring groove of the radial expansion machine case improves the machining efficiency of the ring groove and the radial expansion machine case part and guarantees the machining quality. Specifically, the radial expansion machine case is an integral forging, and when the ring groove is machined, the ring groove is divided into left and right regions in the radial direction, a left-hand tool is used to machine the left region, and a right-hand tool is used to machine the right region. The left side surface of the left-hand tool tip is parallel to the tool bar axis, so that the left-hand tool tip can machine the side wall of the left region and will not interfere with the side wall of the left region when machining the groove bottom. The right side surface of the right-hand tool tip is parallel to the tool bar axis, so that the right-hand tool tip can machine the side wall of the right region and will not interfere with the side wall of the right region when machining the groove bottom. The left-hand tool and the right-hand tool are opposite to each other, the machining efficiency of the ring groove of the radial expansion machine case is improved, and the machining route, the feeding and retracting modes are further designed to guarantee the machining quality.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and more specifically, to a method for machining a radially expanded casing annular groove. Background Technology

[0002] The radial expansion casing is a crucial component of an aero-engine. The "power-to-weight ratio" is a key engine parameter. To improve this ratio, and given a fixed engine power output, minimizing engine weight is essential. Therefore, the radial expansion casing is machined from a large forging as a single piece to reduce component mass. Due to this large forging, the material removal rate is high. For example, a radial expansion casing blank weighs 30.32 kg, while the finished product weighs 5.56 kg, resulting in a material removal rate of 81.66%. The radial expansion casing features annular grooves. When machining these grooves, technicians typically use grooving cutters, end mills, or boring tools. For instance, patent publication CN117697036B, entitled "A CNC Machining Method for End Face Annular Grooves," uses a grooving cutter to machine the end face annular grooves. Because of the high material removal rate of the large forged integral radial expansion casing, the method of machining the annular grooves using a grooving cutter results in a long machining cycle. The applicant conducted an experiment and used a grooving cutter with a cutter width of W=2mm to machine the annular groove of the radial expansion casing. The machining parameters were: rotation speed V=20m / min, feed f=0.05mm / r, depth of cut a=0.7W=1.4mm. Due to the large machining allowance, the material removal rate of the grooving cutter was low, and the single-process machining time was as long as 5 shifts, which seriously affected the delivery of parts and restricted the development of the engine. Summary of the Invention

[0003] This invention provides a method for machining the annular groove of a radially expanded casing. By focusing on the machining of the annular groove, the machining efficiency of the annular groove is improved, thereby increasing the machining efficiency of the radially expanded casing parts and ensuring the machining quality.

[0004] A method for machining a radial expansion casing annular groove, wherein the radial expansion casing is an integral forging, and when machining the annular groove, the annular groove is divided into two regions in the radial direction, namely the left region and the right region, and the left region is machined with a left-hand cutting tool and the right region is machined with a right-hand cutting tool.

[0005] Existing technologies often use grooving cutters and milling cutters when machining annular grooves. However, experiments by technicians have shown that using grooving cutters and milling cutters results in long machining cycles, which restrict engine development. This invention utilizes the structural characteristics of left-hand and right-hand cutting tools to divide the annular groove into two regions. The left-hand cutting tool machines the annular groove from right to left, while the right-hand cutting tool machines it from left to right. Experiments by technicians have shown that this method improves the machining efficiency of the annular groove, thus increasing part processing efficiency and shortening the part processing cycle.

[0006] In this invention, the right-hand cutting tool includes a tool shank and a V-shaped cutting insert mounted on the tool shank, while the left-hand cutting tool includes a tool shank and a V-shaped cutting insert mounted on the tool shank. The V-shaped cutting insert is a rhomboid insert with two symmetrical cutting tips, an indexable insert with two cutting tips, commonly with tip angles of 35°, 55°, and 60°, and a V-shaped pointed shape. When the V-shaped cutting insert is mounted on the tool shank, one side of the cutting tip is parallel to the tool shank axis, and the other side forms a certain angle with the axis; this angle is the tip angle. When mounted on the tool shank, the cutting tip pointing to the left is the left-hand cutting tool, and the cutting tip pointing to the right is the right-hand cutting tool. After the V-shaped cutting insert is mounted on the tool shank, the cutting edge bevel, clearance angle, and chip removal direction are unidirectional, preventing arbitrary tool movement between left and right hands. A single V-shaped cutting insert can only machine internal holes or external circles, and cannot complete the entire groove machining. This invention divides the annular groove into two areas, left and right, and uses two opposite cutting tools for machining, enabling the completion of the entire groove machining.

[0007] Furthermore, the blade tip angles of the left-hand knife and the right-hand knife are equal.

[0008] Furthermore, the blade tip angles of both the left-hand and right-hand knives are 35°.

[0009] Furthermore, the interface between the two regions extends straight from the end edge of the inner hole, conforming to the inner wall of the inner hole, to the bottom of the groove, dividing the annular groove into the right-side region located to the right of the interface and the left-side region located to the left of the interface.

[0010] Furthermore, an auxiliary line is set on the interface, parallel to the interface, extending from the end edge of the inner hole to the bottom of the groove. The auxiliary line is not the actual contour of the workpiece, but a virtual line designed for tool entry positioning.

[0011] This invention, while improving processing efficiency by employing both left- and right-handed cutting tools, also designs the processing route to enhance processing quality: When machining the right-side area using a right-hand cutter, first machine the bottom of the groove in the right-side area, leaving machining allowance for the sidewalls, and then machine the sidewalls of the right-side area. When machining the bottom of the groove in the right-side area, the cutter enters at a 45° angle, machining the bottom of the groove from left to right, and then retracts at a 45° angle. When machining the sidewalls of the right-side area, the cutter enters at a 45° angle from outside the groove, machining to the bottom of the groove, and then retracts along the bottom of the groove at an angle not greater than 2°.

[0012] Retracting the tool at an angle of no more than 2° along the bottom of the groove can effectively solve the problem of tool wear causing incomplete machining and the resulting tool retraction table.

[0013] When machining the left side area using a left-handed tool, first machine the bottom of the groove in the left side area, leaving machining allowance for the side walls, and then machine the side walls of the left side area. When machining the bottom of the groove in the left side area, the tool enters along the bottom of the groove at an angle of no more than 2°, and machines the bottom of the groove from right to left, and then retracts the tool at a 45° angle. When machining the side walls of the left side area, the tool enters from outside the groove at a 45° angle, machines to the bottom of the groove, and then retracts the tool along the bottom of the groove at an angle of no more than 2°.

[0014] Approaching the tool at an angle of no more than 2° along the bottom of the groove can effectively solve the tool-joining table caused by the tool alignment error between the left-hand tool and the right-hand tool. Approaching the tool retracting the tool at an angle of no more than 2° along the bottom of the groove can effectively solve the tool-joining table caused by incomplete machining due to tool wear during machining.

[0015] Furthermore, when the interface is tilted to the right, the distance between the tool's entry point on the auxiliary line and the side wall of the left area is a safe distance, which is greater than or equal to 5mm; when the interface is tilted to the left, the distance between the tool's entry point on the auxiliary line and the side wall of the right area is a safe distance, which is greater than or equal to 5mm.

[0016] To ensure chip removal, further, when the interface is tilted to the right, the angle β between the back face of the left-hand cutting tool and the auxiliary line is ≥5° during machining; when the interface is tilted to the left, the angle β between the back face of the right-hand cutting tool and the auxiliary line is ≥5° during machining.

[0017] To prevent interference between the cutting tool and the workpiece, the angle α between the interface and the bottom of the groove must meet the following requirements: arctan(H / LH*tanθ-5)≤α≤(90°-θ-5°), where H is the depth of the annular groove of the radial expansion housing forging blank, L is the diameter of the annular groove of the radial expansion housing forging blank, and θ is the cutting tool tip angle.

[0018] The present invention has the following beneficial effects: The present invention describes a method for machining the annular groove of a radially expanded casing. This method improves machining efficiency by focusing on the annular groove machining process, thereby increasing the overall machining efficiency of the radially expanded casing parts and ensuring machining quality. Specifically, the radially expanded casing is an integral forging. When machining the annular groove, it is divided into two radial regions: a left-hand region and a right-hand region. A left-handed cutting tool is used to machine the left-hand region, and a right-handed cutting tool is used to machine the right-hand region. The left side of the left-handed cutting tool tip is parallel to the tool shank axis, thus enabling machining of the sidewall of the left-hand region without interference when machining the groove bottom. Similarly, the right side of the right-handed cutting tool tip is parallel to the tool shank axis, enabling machining of the sidewall of the right-hand region without interference when machining the groove bottom. This invention uses opposite left-handed and right-handed cutting tools, improving the machining efficiency of the radially expanded casing annular groove. Furthermore, the machining path, tool entry, and retraction methods are designed to ensure machining quality. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the tool path for machining the radial expansion casing annular groove; Figure 2 This is a schematic diagram of right-hand knife processing; Figure 3 This is a schematic diagram of left-handed cutting. Figure 4 This is a diagram showing the interface division in Example 2; Figure 5 A theoretical mathematical model for the volume of material removed per unit time.

[0020] The serial numbers are: 1 - left-handed knife, 2 - right-handed knife. Detailed Implementation

[0021] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0022] Example 1 A method for machining an annular groove in a radially expanded casing, wherein the radially expanded casing is an integral forging, and during machining of the annular groove, as follows: Figure 2 As shown, the annular groove is divided into two regions in the radial direction, namely the left region and the right region. The interface between the two regions extends straight from the end edge of the inner hole to the bottom of the groove, which is attached to the inner wall of the inner hole. The annular groove is divided into the right region located on the right side of the interface and the left region located on the left side of the interface.

[0023] In this embodiment, the interface is as follows: Figure 2 The right edge of the inner hole extends to the bottom of the groove, meaning the interface slopes to the right. This embodiment uses two blades, one for each hand, to respectively... Figure 2 The two areas shown are processed, such as Figure 1 As shown, left-hand knife 1 processes the left-side area, and right-hand knife 2 processes the right-side area.

[0024] In this embodiment, the blade tip angles of the left-hand knife 1 and the right-hand knife 2 are equal, both at 35°. Figure 1 As shown, the tip of the left-hand cutter 1 is biased to the left, with its left side parallel to the tool shank axis and its right side forming a 35° angle with the tool shank axis. Because the left side of the tip of the left-hand cutter 1 is parallel to the tool shank axis, it can machine the sidewall of the left-hand area without interfering with the sidewall of the left-hand area when machining the bottom of the groove. Similarly, the tip of the right-hand cutter 2 is biased to the right, with its right side parallel to the tool shank axis and its left side forming a 35° angle with the tool shank axis. Because the right side of the tip of the right-hand cutter 2 is parallel to the tool shank axis, it can machine the sidewall of the right-hand area without interfering with the sidewall of the right-hand area when machining the bottom of the groove.

[0025] An auxiliary line is set on the interface to facilitate tool entry positioning. The auxiliary line is parallel to the interface and extends from the end edge of the inner hole to the bottom of the groove. In this invention, the angle between the interface and the bottom of the groove is the angle between the auxiliary line and the bottom of the groove.

[0026] When machining the right-side area using right-hand cutter 2, first machine the bottom of the groove in the right-side area, leaving machining allowance for the sidewalls, then machine the sidewalls of the right-side area; when machining the bottom of the groove in the right-side area, the cutter enters at a 45° angle, machining the bottom of the groove from left to right, and then retracts at a 45° angle; when machining the sidewalls of the right-side area, the cutter enters at a 45° angle from outside the groove, machining to the bottom of the groove, and then retracts at a 2° angle along the bottom of the groove. For example... Figure 1 As shown, the right-hand tool 2 moves along path ①-②-③-④-⑤-⑥ (45-degree infeed-machining the bottom of the groove-45-degree retraction-45-degree infeed-machining the sidewall-retraction at a 2° angle along the bottom of the groove). Retraction at a 2° angle along the bottom of the groove can effectively solve the problem of tool wear causing incomplete machining and the resulting tool stop.

[0027] When machining the left-side area using left-hand tool 1, first machine the bottom of the groove in the left-side area, leaving machining allowance for the sidewalls, then machine the sidewalls of the left-side area. When machining the bottom of the groove in the left-side area, the tool enters at a 2° angle along the bottom of the groove, machining from left to right, and retracts at a 45° angle. When machining the sidewalls of the left-side area, the tool enters at a 45° angle from outside the groove, machining to the bottom of the groove, and retracts at a 2° angle along the bottom of the groove. Figure 1 As shown, left-hand knife 1 along the path - - - - - Perform the tool feed (enter the tool at a 2° angle along the bottom of the groove - machine the bottom of the groove - retract the tool at a 45° angle - enter the tool at a 45° angle - machine the side wall - retract the tool at a 2° angle along the bottom of the groove). Entering the tool at a 2° angle along the bottom of the groove can effectively solve the tool jointing table caused by the tool matching error between the left-hand tool 1 and the right-hand tool 2. Retracting the tool at a 2° angle along the bottom of the groove can effectively solve the tool jointing table caused by the incomplete machining due to tool wear during machining.

[0028] In this embodiment, the right-side area is machined first, followed by the left-side area. In other embodiments, the left-side area may be machined first, followed by the right-side area. For the area machined first, the tool is retracted at a 2° angle after machining the sidewall, effectively resolving the tool wear issue that causes incomplete machining and the resulting tool lag. For the area machined later, a 2° angle is used when machining the groove bottom to resolve the tool lag caused by the misalignment between the left-hand tool 1 and the right-hand tool 2; a 2° angle is used when machining the sidewall to resolve the tool wear issue that causes incomplete machining and the resulting tool lag.

[0029] The distance between the tool's entry point on the auxiliary line and the sidewall of the left-side area is a safety distance to prevent the tool from colliding with the workpiece sidewall. In this example, the safety distance is 5mm. To facilitate chip removal, during machining, the angle β between the back face of the left-hand tool 1 and the auxiliary line is ≥5°. In this embodiment, β = 5°.

[0030] Example 2 A method for machining a radial expansion casing annular groove. This embodiment differs from Embodiment 1 in that the interface is as follows: Figure 4 The left end edge of the inner hole extends to the bottom of the groove, meaning the interface slopes to the left. The distance between the tool's infeed positioning position on the auxiliary line and the sidewall of the right-side area is a safety distance; in this embodiment, the safety distance is 5mm. To facilitate chip removal, during machining, the angle β between the back face of the right-hand cutter 2 and the auxiliary line is ≥5°; in this embodiment, β = 5°.

[0031] Example 3 A machining method for a radial expansion housing ring groove. The difference between this embodiment and Embodiment 1 or Embodiment 2 is that, in order to ensure that the tool does not interfere with the part during machining and to ensure normal machining, the included angle α between the auxiliary line and the bottom of the groove must meet the following requirements: arctan(H / LH*tan35°-5)≤α≤50°, where H is the depth of the ring groove of the radial expansion housing forging blank, L is the diameter of the ring groove of the radial expansion housing forging blank, and θ is the tool tip angle.

[0032] Combined with appendix Figure 2 The calculation process for the range of angle α is as follows: L1 = H1 * tan35° (L1 ≤ 25°) L2=H1 / tanα L3 = L - L1 - L2 = L - H1 * tan35° - H1 / tanα (Based on the test, the safe distance L3 ≥ 5) When H1=H, the tool and the workpiece do not interfere with each other, meaning that there will be no interference during the entire machining process.

[0033] L3 = LH * tan35° - H / tanα ≥ 5 Therefore: α≥arctan(H / LH*tan35°-5) Tool tip angle + ∠β + α = 90° (to ensure normal chip removal during machining, ∠β ≥ 5°) ∠β=90° - knife-edge angle - α≥5° Therefore: α≤50° In summary: arctan(H / LH*tan35°-5)≤α≤50°.

[0034] Comparison of machining annular grooves using the method described in Example 3 and machining annular grooves using a grooving cutter: Establish a theoretical mathematical model for the material removal rate per unit time (e.g.) Figure 5 When the machining radius R is 160mm, the material removal rate per unit time for a 2mm wide grooving cutter is calculated to be 7.74 mm3 / s, and the material removal rate per unit time for a 35° cutter is 66.31 mm3 / s. The material removal rate is increased by 8.56 times. Therefore, using a 35° cutter can improve machining efficiency compared to a grooving cutter.

[0035] 1. Calculation of material removal rate when machining with a W=2mm grooving tool: (Spindle speed V = 20 m / min, feed rate f = 0.05 mm / r, depth of cut a = 0.7 W mm) Tool cutting width: AD = 0.7Wmm; The distance the tool travels radially per unit time: AB = 1000V / 60 = 50V / 3 mm; The distance the tool travels along the axial direction per unit time: AA1 = f * (AB / 2πR) = 25Vf / 3πR mm (R is the radius of the area machined by the tool). Therefore: the material removal rate per unit time Q = AD * AB * AA1 = 0.7W * 50V / 3 * 25Vf / 3πR = 875WfV2 / 9πR = 7.74mm3 / s; 2. Calculation of material removal rate during machining with a 35° cutter: (Spindle speed V = 50 m / min, feed rate f = 0.12 mm / r, depth of cut a = 0.8 mm) Cutting tool: AD = f * (AB / 2πR) = 25Vf / 3πR mm (R is the radius of the area machined by the cutting tool); The distance the tool travels radially per unit time: AB = 1000V / 60 = 50V / 3 mm; The distance the tool travels along the axial direction per unit time: AA1 = a = 0.8 mm; Therefore: the material removal rate per unit time Q = AD * AB * AA1 = 25Vf / 3πR * 50V / 3 * 0.8 = 1000fV2 / 9πR = 66.31 mm3 / s.

[0036] Compared to using a grooving cutter to process ring grooves, the processing time per operation was reduced from 5 shifts to 3.5 shifts by using a 35° forward and reverse cutting tool, increasing efficiency by 30%, and no quality problems were generated after the parts were processed.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the present invention.

Claims

1. A method for machining a radially expanded casing annular groove, characterized in that, The radial expansion housing is an integral forging. When machining the annular groove, the annular groove is divided into two regions in the radial direction, namely the left side region and the right side region. The left side region is machined with a left-handed cutting tool, and the right side region is machined with a right-handed cutting tool.

2. The machining method for the radial expansion casing annular groove according to claim 1, characterized in that, The blade tips of the left-hand knife and the right-hand knife have the same angle.

3. The machining method for the radial expansion casing annular groove according to claim 2, characterized in that, The blade tip angle of both the left-hand knife and the right-hand knife is 35°.

4. The machining method for the radial expansion casing annular groove according to claim 2, characterized in that, The interface between the two regions extends straight from the end edge of the inner hole, adhering to the inner wall of the inner hole, to the bottom of the groove, dividing the annular groove into a left region located to the left of the interface and a right region located to the right of the interface.

5. The method for machining the radial expansion casing annular groove according to claim 4, characterized in that, An auxiliary line is set on the interface, parallel to the interface, and extends from the end edge of the inner hole to the bottom of the groove.

6. The method for machining the radial expansion casing annular groove according to claim 5, characterized in that, When machining the right-side area using a right-hand cutter, first machine the bottom of the groove in the right-side area, leaving machining allowance for the sidewalls, and then machine the sidewalls of the right-side area. When machining the bottom of the groove in the right-side area, the cutter enters at a 45° angle, machining the bottom of the groove from left to right, and then retracts at a 45° angle. When machining the sidewalls of the right-side area, the cutter enters at a 45° angle from outside the groove, machining to the bottom of the groove, and then retracts along the bottom of the groove at an angle not greater than 2°.

7. The method for machining the radial expansion casing annular groove according to claim 6, characterized in that, When machining the left side area using a left-handed tool, first machine the bottom of the groove in the left side area, leaving machining allowance for the side walls, and then machine the side walls of the left side area. When machining the bottom of the groove in the left side area, the tool enters along the bottom of the groove at an angle of no more than 2°, and machines the bottom of the groove from right to left, and then retracts the tool at a 45° angle. When machining the side walls of the left side area, the tool enters from outside the groove at a 45° angle, machines to the bottom of the groove, and then retracts the tool along the bottom of the groove at an angle of no more than 2°.

8. The method for machining the radial expansion casing annular groove according to claim 7, characterized in that, When the interface is tilted to the right, the distance between the tool's entry point on the auxiliary line and the side wall of the left area is a safe distance, which is greater than or equal to 5mm; when the interface is tilted to the left, the distance between the tool's entry point on the auxiliary line and the side wall of the right area is a safe distance, which is greater than or equal to 5mm.

9. The method for machining the radial expansion casing annular groove according to claim 8, characterized in that, When the interface is tilted to the right, during machining, the angle β between the back face of the left-hand cutting tool and the auxiliary line is ≥5°; when the interface is tilted to the left, during machining, the angle β between the back face of the right-hand cutting tool and the auxiliary line is ≥5°.

10. The method for machining the radial expansion casing annular groove according to claim 9, characterized in that, The angle α between the interface and the bottom of the groove must meet the following requirements: arctan(H / LH*tanθ-5)≤α≤(90°-θ-5°), where H is the depth of the annular groove of the radial expansion housing forging blank, L is the diameter of the annular groove of the radial expansion housing forging blank, and θ is the blade tip angle.

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