A method for processing frame segment parts

Abstract

The present invention discloses a method for processing frame segment parts, the specific steps of which include die forging blank, inspection and marking, first rough machining, ultrasonic flaw detection, inspection and marking, repair of reference bottom surface and drilling of reference holes, second rough machining, aging treatment, repair of reference bottom surface and reference holes, precision milling of bottom surface, precision milling of grid cavity, drilling and blanking, and finished product inspection. The present invention analyzes the structure and processability of titanium alloy special-shaped frame segments, optimizes and improves the processing technology in terms of rough machining part stability, tool use stability, precision machining efficiency, quality, and operator interaction, proposes pre-correction measures such as a web thin area clamping device, a tool validation table, and precision milling of two-sequence docking planes, solves the problem of stress lateral bending and warping of semicircular arc frame segments caused by titanium alloy material properties, and provides a reference for the manufacture of products with similar structures.

Description

Technical Field

[0001] The invention relates to the field of aviation parts manufacturing, and in particular to a frame segment parts processing method. Background Art

[0002] Titanium alloys are used extensively in critical load-bearing components such as aircraft fuselage frames due to their lightweight, high specific strength, excellent heat resistance, and excellent corrosion resistance. The density of titanium alloys is typically approximately 4.5 g / cm³, while alloy steels have a minimum density of 7.9 g / cm³, approximately 1.75 times that of titanium alloys. Titanium alloys are stronger than many structural steel alloys, and their specific strength (strength / density ratio) is far greater than that of other metallic structural materials. The resulting parts exhibit high specific strength, excellent rigidity, and low weight, making them widely used in aerospace. However, titanium alloys frequently oxidize with atmospheric oxygen, nitrogen, carbon dioxide, and other substances, forming a strong and hard protective oxide film. Furthermore, their inherent damping resistance is low, resulting in a deformation coefficient of less than or equal to 1. Titanium alloys with a hardness greater than HB350 are particularly difficult to cut, while those with a hardness less than HB300 are prone to tool sticking. The aluminum chips generated during cutting titanium alloys also cause significantly greater tool wear than those produced by conventional alloys. However, for parts like frame segments, which require large removal volumes, inadequate process analysis and planning can lead to significant vibration during the cutting process, which concentrates cutting heat at the cutting point, exacerbating tool wear and causing tool blunting. This in turn increases cutting forces, impacting part quality and causing excessive deformation. Therefore, in order to better optimize and control the titanium alloy milling process, it is particularly important to effectively address milling forces and process stability during the milling of titanium alloy frame segments.

[0003] like Figure 1 The picture shows a titanium alloy frame section for an aircraft. This semicircular, double-sided frame is made of Ti6Al4V. During the trimming process, uneven stock removal and improper process design can easily lead to part warping and deformation. Partial webs are thin, and the large amount of metal removed during milling causes localized dimensional stress accumulation, causing warping or collapse in these thin webs. Milling strength is poor at the arc, and after rough machining, stress release leads to poor strength and bending, causing the part to bend laterally and increase the arc size. Summary of the Invention

[0004] The present invention provides a frame segment parts processing method, which solves the following technical problems:

[0005] (1) Overcome the poor cutting performance of titanium alloy materials due to the large allowance on the rough machining plane of parts, large allowance on the rough machining side wall, second rough machining plane trimming, fine machining plane trimming, large cutting depth on the fine machining side wall, and fast finishing.

[0006] (2) Solve the problem of inaccurate position of special-shaped products in forging blanks.

[0007] (3) Overcome the stress warping of parts caused by removing large allowances during milling of forging blanks.

[0008] (4) Solve the problem of removing large allowances on the side walls during milling of forging blanks and reducing tool life due to corner cutting.

[0009] (5) Overcome the stress warping and lateral bending of the forging blank caused by the destruction of the material fiber direction during roughing.

[0010] (6) Overcome the stress warping and lateral bending of forged parts caused by the slow release of residual stress during the finishing process.

[0011] (7) Solve the problem of rapid product processing while ensuring the product surface roughness Ra3.2.

[0012] (8) Solve the impact of milling vibration on the surface quality of parts.

[0013] (9) Solve the problem of large errors in repeated clamping of special-shaped parts and the cumulative clamping errors that are easy to cause.

[0014] (10) Solve the problem of local stress deformation of the web of special-shaped parts caused by clamping, extrusion and insufficient clamping force over a large area.

[0015] (11) Solve the problem of incorrect tool usage, which may cause overcutting or undercutting of parts during milling.

[0016] (12) Solve the problem of gravity pulling on the boss during the transfer process, which causes parts to tear.

[0017] To achieve the above objectives, the present invention provides the following technical solutions:

[0018] A method for processing a frame segment part comprises the following steps:

[0019] S1, receiving the die forging blank;

[0020] S2, Inspection and Marking: The die forging blank is inspected and marked, and the thickness center line of the part blank is marked using a height gauge and ink. Then, the maximum solid contour line of the part is marked using a marking knife on a CNC machine tool;

[0021] S3, the first rough machining: the upper and lower surfaces of the blank are machined using the CNC milling plate side top clamping, with a single side allowance of 6mm in the thickness direction of the part, and the parallelism of the upper and lower planes of the workpiece is not greater than 0.20mm;

[0022] S4, ultrasonic flaw detection: After the first rough machining is completed, the workpiece needs to be ultrasonically inspected. After the workpiece is inspected by ultrasonic flaw detection, the casting defect area is marked;

[0023] S5, check marking, repair base surface and drill base hole: Use the marking cutter on the CNC machine to check marking for the second time, use the CNC machine to process the base hole and screw countersunk hole of the part, use the screw to install in the screw countersunk hole, connect and lock the workpiece and the machine table, and fix the workpiece;

[0024] S6, second rough machining: the machining coordinate system is set to the pin hole at the left end of the part, and the outer side wall of the part is machined by CNC milling to machine the inner cavity of the part. The milling process adopts the down milling method;

[0025] S7, machining inner cavity: Use fast feed milling cutter and down milling method to machine the inner cavity of the part. Rough machining the inner cavity side wall and ribs with a single side allowance of 3mm and a bottom allowance of 2mm. Machine the support column and support ribs in the inner cavity of the part.

[0026] S8, aging treatment: After completing the second rough machining, the parts are removed from the machine table and placed on the platform for natural aging;

[0027] S9, repair the base surface and drill the base hole: Place the part flat on the CNC machine table, use two screws to install it on the left and right end surfaces of the part respectively, with the end surface of the part fitting the cylindrical surface of the screw head, and use the end surface of the pressure plate to fit the side surface of the part in the rest of the position. This completely restricts the freedom of the part in the X and Y directions. Use a plane milling cutter to trim the part base surface, process boss support surface, and pin hole. The removal amount on a single side should be greater than the warping deformation amount, and the finishing removal allowance is 0.30mm.

[0028] S10, fine milling of the bottom surface: adjust the machining coordinate system to the center axis of the part arc, use the tool calibration table to check the diameter of the tool to be used, the tool clamping length, and the tool tip radius, and then fine mill the bottom surface of the part;

[0029] S11, fine milling of the grid cavity (3): using a clamping fixture to clamp the part, and fine milling the grid cavity (3) of the part;

[0030] S12, drilling and blanking; the part and fixture are not separated and are transferred as a whole to the five-axis CNC machining center. The butt joint is milled with a solid hard end mill, the part position is checked, the part machining coordinate system is adjusted, and after a test drilling with a special elbow and a special drill bit, the positioning holes on the side wall of the part are drilled. The blanking and milling process is carried out on the table.

[0031] S13, finished product inspection: check whether all indicators of parts are qualified.

[0032] The specific method for machining the upper and lower surfaces of the blank in the first rough machining in step S3 is as follows: when CNC milling the upper and lower surfaces of the blank, machining is carried out along the fiber direction of the blank, using a flat milling cutter with a large diameter and a large tool tip radius, a milling cutter diameter of Φ63 mm, and a tool tip radius of R8 mm; the machine tool spindle speed is 177 r / min; the feed speed is 214 mm / min; the cutting width is 40 mm; the rough trimming cutting depth is 1.30 mm, and the finishing cutting depth is 0.30 mm.

[0033] The specific steps for processing the screw countersunk holes in step S5 are: using a CNC machine tool to process 15 screw countersunk holes that are evenly or symmetrically distributed along the outer contour of the part, the distance between the center of the countersunk hole and the boundary of the part is 50~60mm, the distance between the wall of the screw countersunk hole and the surface of the screw head is maintained at 4mm~5mm, the depth of the countersunk step hole is not less than 3mm than the length of the screw head, and the distance between the screw rod and the side wall of the through hole is 2mm~3mm.

[0034] The specific method for processing the outer side wall in step S6 is: using a corn milling cutter to mill the outer side wall, the processing parameters of low speed and large feed rate, and the tool path are processed at an oblique angle to the outer contour of the part, leaving a single-side allowance of 3mm for the part, and milling 15 process bosses at the position of the screw countersunk hole. The specific processing parameters are: tool diameter Φ32mm, tool tip radius R3.1mm; machine tool spindle speed 398 r / min; feed speed 143 mm / min; cutting width 6mm; cutting depth 18mm.

[0035] The step S11 includes the following sub-steps:

[0036] S1101: Finish milling of the mesh cavity surface using a 16mm diameter solid hard end mill with a 1mm tip radius. On each boss sidewall, milling is performed parallel to the XZ and YZ axis planes. A dial indicator is used to measure the offset values ​​during the finishing process. The measured data is used to determine if the part has been properly clamped.

[0037] S1102, Review the part docking status: Use fine milling to remove 0.50mm of the inner wall of the part. Set up a thickness gauge to check the dimensions. Adjust the part machining coordinate system based on the actual test results.

[0038] S1103, a clamping device is designed for the thin area of ​​the web;

[0039] S1104, the precision milling of the inner cavity side wall adopts the pre-clearing corner method, adopts the milling method of large cutting depth and small cutting width similar to trochoidal milling, and uses radial layer milling of 0.80mm per layer when precision milling the side wall, and finally trims the outer side wall by 0.10mm.

[0040] The specific method of drilling in step S12 is: after qualified trial drilling using a special elbow and a special drill bit, drilling the positioning hole on the side wall of the part; the main process parameters are: tool type carbide drill bit, tool diameter Φ3mm, tool tip angle 140°; machine tool spindle speed 1260 r / min; feed speed 35 mm / min; cutting depth 2mm, and the specific method of blanking is: milling thinning the connection between the process boss and the part in the order from high to bottom and from outside to inside.

[0041] The present invention has the following advantages and beneficial effects:

[0042] By analyzing the structure and processability of titanium alloy special-shaped frame segments, the processing technology was optimized and improved in terms of rough machining part stability, tool use stability, fine machining efficiency, quality, and operator interaction. Pre-correction measures such as web thin area clamping device, tool calibration table, and fine milling two-sequence docking plane were proposed. The problems of titanium alloy material properties and stress lateral bending and warping of semicircular arc frame segments were solved, providing a reference for the manufacturing of products with similar structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the product of the present invention

[0044] Figure 2 This is a schematic diagram of the boss screw sinking process of the present invention;

[0045] Figure 3 This is a schematic diagram of the milling partitioning of the present invention;

[0046] Figure 4 This is a schematic diagram of the bevel milling process of the present invention;

[0047] Figure 5 Schematic diagram of the grid cavity support column and support rib of the present invention;

[0048] Figure 6 It is a schematic diagram of blanking of the present invention.

[0049] In the figure, 1-external side wall, 2-inner cavity, 3-grid cavity, 4-support rib, 5-support column, 6-process boss, 7-pin hole, 8-screw countersunk hole, 9-web thin area. DETAILED DESCRIPTION

[0050] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0051] like Figures 1-6A method for processing a frame segment part comprises the following steps:

[0052] S1, receiving the die forging blank;

[0053] S2, Inspection and Marking: The die forging blank is inspected and marked, and the thickness center line of the part blank is marked using a height gauge and ink. Then, the maximum solid contour line of the part is marked using a marking knife on a CNC machine tool;

[0054] S3, the first rough machining: the upper and lower surfaces of the blank are machined using the CNC milling plate side top clamping, with a single side allowance of 6mm in the thickness direction of the part, and the parallelism of the upper and lower planes of the workpiece is not greater than 0.20mm;

[0055] S4, ultrasonic flaw detection: After the first rough machining is completed, the workpiece needs to be ultrasonically inspected. After the workpiece is inspected by ultrasonic flaw detection, the casting defect area is marked;

[0056] S5, check and mark, repair the base surface and drill the base hole: Use the marking tool on the CNC machine to perform a second check and mark, use the CNC machine to machine the base hole and screw countersunk hole 8 of the part, use the screw to install it in the screw countersunk hole 8, connect and lock the workpiece and the machine table, and fix the workpiece;

[0057] S6, second rough machining: the machining coordinate system is set to the pin hole 7 at the left end of the part, and the outer side wall 1 of the part is machined by CNC milling to machine the inner cavity 2 of the part. The milling process adopts the down milling method;

[0058] S7, machining inner cavity 2: using a fast feed milling cutter, machining the inner cavity 2 of the part by down milling, rough machining the side walls and ribs of the inner cavity 2 with a single-side allowance of 3mm and a bottom allowance of 2mm, machining the support column 5 and the support rib 4 in the inner cavity 2 of the part;

[0059] S8, aging treatment: After completing the second rough machining, the parts are removed from the machine table and placed on the platform for natural aging;

[0060] S9, repair the base bottom surface and drill the base hole: Place the part flat on the CNC machine tool workbench, use two screws to install it on the left and right end surfaces of the part respectively, with the end surface of the part fitting the cylindrical surface of the screw head, and use the end surface of the pressure plate to fit the side surface of the part in the rest of the position, so that the freedom of the part in the X and Y directions is completely restricted. Use a plane milling cutter to trim the base surface of the part, the support surface of the process boss 6, and the pin hole 7. The removal amount of each side should be greater than the warping deformation amount, and the finishing removal allowance is 0.30mm;

[0061] S10, fine milling of the bottom surface: adjust the machining coordinate system to the center axis of the part arc, use the tool calibration table to check the diameter of the tool to be used, the tool clamping length, and the tool tip radius, and then fine mill the bottom surface of the part;

[0062] S11, fine milling of grid cavity 3: using a clamping fixture to clamp the part, and fine milling of the grid cavity 3 of the part;

[0063] S12, drilling and blanking; the part and fixture are not separated and are transferred as a whole to the five-axis CNC machining center. The butt joint is milled with a solid hard end mill, the part position is checked, the part machining coordinate system is adjusted, and after a test drilling with a special elbow and a special drill bit passes, a positioning hole is drilled on the side wall of the part. The blanking and milling process is carried out on the table.

[0064] S13, finished product inspection: check whether all indicators of parts are qualified.

[0065] The specific method for processing the upper and lower surfaces of the blank in the first rough processing in step S3 is as follows: when CNC milling the upper and lower surfaces of the blank, in order to improve the part processing efficiency and surface quality, the blank is processed along the fiber direction without destroying the internal organizational structure of the blank, and a large-diameter, large-tip radius flat milling cutter is used, with a milling cutter diameter of Φ63mm and a tip radius of R8mm; the machine tool spindle speed is 177 r / min; the feed speed is 214 mm / min; the cutting width is 40mm; the rough trimming cutting depth is 1.30mm, and the fine trimming cutting depth is 0.30mm. If the tool diameter is small, the part processing efficiency is low and the cost is high; if the tip radius is small, the tip impact resistance is insufficient, and the tool edge is prone to cracking, resulting in unqualified part processing or even scrapping.

[0066] The specific steps of processing the screw countersunk holes 8 in step S5 are as follows: using a CNC machine tool to process 15 screw countersunk holes 8 that are evenly or symmetrically distributed along the contour of the part, the distance between the center of the countersunk hole and the part boundary is 50~60mm, the screw distance is set to more than 60mm, the pressing force cannot effectively overcome the cutting vibration, the roughness of the part is poor and the screws are easy to loosen for a long time, causing the part to shift and overcut and be scrapped; the screw distance is set to less than 50mm, and the setting distance of each action area is reduced accordingly, resulting in milling difficulties, uneven force on the load-bearing plane, The small tightening force of the screw is insufficient, which causes the screw to loosen. The distance between the wall of the screw countersunk hole 8 and the surface of the screw head is maintained at 4mm~5mm. After rough processing, the stress in the workpiece is released and deformation occurs, and the position of the screw countersunk hole is offset. If the diameter of the countersunk hole is too small, it is easy to cause the hole wall and the cylindrical surface of the screw to be squeezed and contacted, causing serious stress concentration, affecting the subsequent processing quality. Ensure that the force area of ​​the screw pressing the workpiece is sufficient and the workpiece does not move during processing. The depth of the countersunk step hole is not less than 3mm than the length of the screw head, and the distance between the screw and the side wall of the through hole is 2mm~3mm.

[0067] The specific method for machining the exterior sidewall 1 in step S6 is as follows: milling the exterior sidewall 1 with a corn milling cutter, using low-speed, high-feed machining parameters, and machining with a tool path at an angle to the part's exterior contour. A 3mm single-side allowance is left on the part, and 15 process bosses 6 are milled at the locations of the screw countersunk holes 8. The machining parameters are: tool diameter Φ32mm, tool tip radius R3.1mm; spindle speed 398 rpm; feed rate 143 mm / min; cutting width 6mm; and cutting depth 18mm. The process bosses are connected at right angles to the part. Right-angle milling can produce a "three-sided cutting" phenomenon, causing a surge in spindle power and sharp tool vibration, impacting spindle life, tool life, and part surface quality. Conventional solutions involve improving the milling angle from a right angle to a larger radius and reducing the feed rate to protect the spindle, but this increases milling time and cost. Milling with a tool path at an angle to the part's exterior contour solves these machining issues.

[0068] The step S11 includes the following sub-steps:

[0069] S1101: Finish milling of the three surfaces of the mesh cavity using a 16mm diameter solid hard end mill with a 1mm tip radius. Milling of surfaces parallel to the XZ and YZ axis planes is performed on the sidewalls of each process boss. A dial indicator is used to measure the offset values ​​during the two finishing steps. The measured data is used to determine if the part has been properly clamped.

[0070] S1102, Review the part docking status: Use fine milling to remove 0.50mm of the inner wall of the part. Set up a thickness gauge to check the dimensions. Adjust the part machining coordinate system based on the actual test results.

[0071] S1103, design a clamping device in the web thin area 9;

[0072] S1104, the precision milling of the inner cavity side wall adopts the pre-clearing corner method, adopts the milling method of large cutting depth and small cutting width similar to trochoidal milling, and uses radial layer milling of 0.80mm per layer when precision milling the side wall, and finally trims the outer side wall 1 by 0.10mm.

[0073] The specific method of drilling and blanking in step S12 is: after qualified trial drilling using a special elbow and a special drill bit, drilling a positioning hole in the outer side wall 1 of the part; the main process parameters are: tool type carbide drill bit, tool diameter Φ3mm, tool tip angle 140°; machine tool spindle speed 1260 r / min; feed speed 35 mm / min; cutting depth 2mm, and the specific method of blanking is: milling thinning the connection between the process boss 6 and the part in the order from high to bottom and from outside to inside.

[0074] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments. Various modifications are possible within the scope of ordinary skill in the art without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A method for processing a frame segment part, characterized in that: The steps include: S1, receiving the die forging blank; S2, Inspection and Marking: The die forging blank is inspected and marked. The thickness center line of the part blank is marked using ink and a height gauge. Then, the maximum solid contour line of the part is marked using a marking knife on a CNC machine tool. S3, first rough machining: Use CNC milling plate side top clamping to machine the upper and lower surfaces of the blank, leaving a 6mm allowance on one side in the thickness direction of the part, and the parallelism of the upper and lower planes of the milled workpiece is not greater than 0.20mm; S4, ultrasonic flaw detection: After the first rough machining is completed, the workpiece needs to be ultrasonically inspected. After the workpiece is inspected by ultrasonic flaw detection, the casting defect area is marked; S5, check the marking, repair the base surface and drill the base hole: use the marking knife on the CNC machine tool to check the marking for the second time, use the CNC machine tool to process the base hole and the screw countersunk hole (8) of the part, use the screw to install it in the screw countersunk hole (8), connect and lock the workpiece and the machine tool workbench, and fix the workpiece; S6, second roughing: the machining coordinate system is set at the pin hole (7) at the left end of the part, and the outer side wall (1) of the part is machined by numerical milling to machine the inner cavity (2) of the part, and the milling process adopts the down-milling method; S7, machining the inner cavity (2): using a fast feed milling cutter, machining the inner cavity (2) of the part by down milling, rough machining the side wall and rib of the inner cavity (2) with a single-side allowance of 3mm, and a bottom allowance of 2mm, machining the support column (5) and the support rib (4) in the inner cavity (2) of the part; S8, aging treatment: After completing the second rough machining, the parts are removed from the machine table and placed on the platform for natural aging; S9, repair the base bottom surface and drill the base hole: Place the part flat on the CNC machine table, use two screws to install it on the left and right end surfaces of the part respectively, and fit the end surface of the part to the cylindrical surface of the screw head. Use the end surface of the pressure plate to fit the side surface of the part in the other positions, so that the freedom of the part in the X and Y directions is completely restricted. Use a flat milling cutter to trim the base surface of the part, the support surface of the process boss (6), and the pin hole (7). The amount of removal on a single side should be greater than the amount of warping deformation. The finishing removal allowance is 0.30mm. S10, fine milling of the bottom surface: adjust the machining coordinate system to the center axis of the part arc, use the tool calibration table to check the diameter of the tool to be used, the tool clamping length, and the tool tip radius, and then fine mill the bottom surface of the part; S11, fine milling of the grid cavity (3): using a clamping fixture to clamp the part, and fine milling the grid cavity (3) of the part; S12, drilling and blanking; the parts and fixtures are not separated and are transferred as a whole to the five-axis CNC machining center; the butt joint is milled by a solid hard end mill, the position of the parts is detected, the machining coordinate system of the parts is adjusted, and after the test drilling is qualified with a special elbow and a special drill bit, the positioning hole (1) of the side wall of the part is drilled; blanking and milling process table; S13, finished product inspection: check whether all indicators of parts are qualified.

2. A method for processing a frame segment part according to claim 1, characterized in that: The specific method for machining the upper and lower surfaces of the blank in the first rough machining in step S3 is as follows: when CNC milling the upper and lower surfaces of the blank, machining is carried out along the fiber direction of the blank, using a flat milling cutter with a large diameter and a large tool tip radius, a milling cutter diameter of Φ63 mm, and a tool tip radius of R8 mm; the machine tool spindle speed is 177 r / min; the feed speed is 214 mm / min; the cutting width is 40 mm; the rough trimming cutting depth is 1.30 mm, and the finishing cutting depth is 0.30 mm.

3. A method for processing a frame segment part according to claim 1, characterized in that: The specific steps of processing the screw countersunk holes (8) in step S5 are as follows: using a CNC machine tool to process 15 screw countersunk holes (8) evenly or symmetrically distributed along the outer contour of the part, the distance between the center of the countersunk hole and the boundary of the part is 50~60mm, the distance between the wall surface of the screw countersunk hole (8) and the surface of the screw head is maintained at 4mm~5mm, the depth of the countersunk step hole is not less than 3mm greater than the height of the screw head, and the distance between the screw rod and the side wall of the through hole is 2mm~3mm.

4. A method for processing a frame segment part according to claim 1, characterized in that: The specific method for processing the outer side wall (1) in step S6 is as follows: using a corn milling cutter to mill the outer side wall (1), processing parameters of low speed and large feed rate, and processing the tool path in a manner that is oblique to the outer contour of the part, leaving a single-side allowance of 3mm for the part, and milling 15 process bosses (6) at the position of the screw countersunk hole (8). The specific processing parameters are: tool diameter Φ32mm, tool tip radius R3.1mm; machine tool spindle speed 398 r / min; feed speed 143 mm / min; cutting width 6mm; cutting depth 18mm.

5. A method for processing a frame segment part according to claim 1, characterized in that: The step S11 includes the following sub-steps: S1101, fine milling the mesh cavity (3) surface using a solid hard end mill with a tool diameter of 16mm and a tip radius of R1mm. Milling the surface parallel to the XZ axis plane and the YZ axis plane on the side wall of each process boss (6). Using a lever dial indicator to detect the specific offset values ​​of the two sequences of fine milling, determine whether the part is qualified for clamping based on the measured data; S1102, Review the part docking status: Use fine milling to remove 0.50mm of the inner wall of the part, set up a thickness gauge to check the dimensions, and adjust the part processing coordinate system based on the actual test results; S1103, design a clamping device in the thin web area (9); S1104, the precision milling of the inner cavity side wall adopts the pre-clearing corner method, adopts the milling method of large cutting depth and small cutting width similar to cycloidal milling, when the side wall is precision milled, 0.80mm radial layer milling is used for each layer, and 0.10mm milling of the outer side wall is used for finishing (1).

6. A method for processing a frame segment part according to claim 1, characterized in that: The specific method of drilling in step S12 is: after the test drilling is qualified using a special elbow and a special drill bit, a positioning hole is drilled on the outer side wall (1) of the part; the specific process parameters are: tool type carbide drill bit, tool diameter Φ3mm, tool tip angle 140°; machine tool spindle speed 1260 r / min; feed speed 35 mm / min; cutting depth 2mm; the specific method of blanking is: milling the connection between the process boss (6) and the part in the order from high to bottom and from outside to inside.

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