CN113500424B

CN113500424B - Numerical control vertical lathe machining method for large-caliber ultrathin-wall part of aircraft engine

Info

Publication number: CN113500424B
Application number: CN202110842586.6A
Authority: CN
Inventors: 唐建国; 王思慧; 仝少博; 窦爱国; 王永清; 唐志军
Original assignee: WUXI RUNHE BLADE MANUFACTURING CO LTD; Wuxi Runhe Machinery Co ltd
Current assignee: Wuxi Runhe Blade Manufacturing Co Ltd; Wuxi Runhe Machinery Co ltd
Priority date: 2021-07-26
Filing date: 2021-07-26
Publication date: 2022-06-14
Anticipated expiration: 2041-07-26
Also published as: CN113500424A

Abstract

A machining method of a numerical control vertical lathe mill for an aircraft engine large-caliber ultrathin-wall part comprises the steps of utilizing high-temperature-resistant alloy powder to print the large-caliber ultrathin-wall part through a material increase technology in a 3D mode, discharging machining allowance of 8-15% of the wall thickness of the two end connecting parts of a workpiece during 3D material increase, heating to 1160-1195 ℃ through a heat treatment process, keeping the temperature for 1-36 hours, and then cooling to the room temperature; a high-frequency heating method is adopted, and the heat preservation is realized by controlling the current of a high-frequency coil; the processed blank is turned by a tool and a numerical control vertical lathe, a chassis of the numerical control vertical lathe is formed by modifying a rotary shaft chuck into a rotary centering bottom plate to drive a workpiece to rotate, a rotary Z shaft is vertical to a horizontal plane, and a tool bit of the turning tool can be programmed to carry out translation of an XZ shaft and turning of an up-and-down feeding control turning tool.

Description

Numerical control vertical lathe machining method for large-caliber ultrathin-wall parts of aircraft engines

Technical Field

The invention relates to a processing method of an ultrathin-wall part of an aircraft engine, in particular to a processing method of a large-caliber ultrathin-wall part of an aircraft engine through 3D printing and numerical control vertical turning.

Background

The annular large-caliber ultrathin-wall part of the aero-engine, namely a workpiece called as a cylinder or a cone, is an atmospheric flow mode conversion mechanism (or a variable circulation mechanism) mechanism of a high-pressure section and a low-pressure section of the aero-engine, and part of parts mounted on the part are of a fin-shaped structure. The length can be more than 50 cm and even 80-90 cm, the thinnest part of the wall thickness is less than 1.2 mm, and better dynamic characteristics are required. The opening and closing sizes of all the blades are controlled by a conduction system of the synchronous ring mechanism, so that the distribution of the atmospheric flow of the engine duct is realized, and the regulation and control of the thermodynamic parameters of the engine performance are realized.

The inner wall and the outer wall of the blade required by the blade have excellent roundness and smoothness, the precision requirement is high (10 micron precision), and the blade can resist high temperature and has small thermal deformation, thereby reducing the air flow leakage loss and improving the efficiency of an aeroengine. In case of common vibration friction, the large-caliber ultrathin-wall part is designed to have the wall thickness of about 0.25mm, so that the damping effect can be achieved, the vibration of the mechanism can be effectively reduced by using the annular large-caliber ultrathin-wall part, and the stable and efficient operation of the aero-engine under the severe working condition can be ensured.

The annular large-caliber ultrathin-wall part of the aircraft engine needs to adopt nickel-based high-temperature-resistant alloy.

CN201610812806.X A titanium alloy thin-wall shell casting blank finish machining mold comprises an outer casting mold coated outside the casting blank, and an inner casting mold coated inside the casting blank; the outer surface of the titanium alloy thin-wall shell casting blank is subjected to external casting of the fusible alloy, so that the outer surface of the titanium alloy thin-wall shell is thickened, and the thin-wall deformation is avoided when the inner surface is cut.

The processing tool and the processing method of the precise stepped hole of the CN201410000998.5 aluminum alloy thin-wall case connect the turning tool and the tool apron of the machine tool through the turning tool rod seat, thereby increasing the cutting range of the turning tool, improving the degree of freedom of the turning tool, and particularly facilitating the turning tool to extend into the thin-wall case when the precise stepped hole of the aluminum alloy thin-wall case is processed. According to the machining method, the large end of the thin-wall casing is placed on the fixture with the small end upward, then the screw hole in the clamping fixing surface of the large end of the thin-wall casing is aligned with the screw hole in the clamping fixing surface of the fixture, the thin-wall casing is clamped and fixed on the fixture through the screw, and then the step hole is machined.

The numerical control vertical lathe chassis is a rotary shaft chuck or is modified into a rotary platform to drive a workpiece to rotate in a circling way, a rotary Z shaft is vertical to a horizontal plane, a lathe tool bit can be programmed to carry out XY translation and control turning of a lathe tool in an up-and-down precession mode, the lathe tool has no rotary function, although the numerical control vertical lathe chassis is widely applied and has low cost price, the numerical control vertical lathe chassis cannot be directly used for processing the thin shell component, and a multi-shaft numerical control milling center is required to be used for processing a fin-shaped structure under any condition, so that the processing on a thin plate is extremely difficult, and the processing efficiency is not high; and if a multi-axis numerical control milling center is utilized to process thick cylinder materials, the working hours are too long, the programming and the adjustment of a machine tool are extremely difficult, and the yield can be high: under the mechanical cutting force, most of the material is deflected to the other side due to the cutting of the base material.

If the large-caliber ultrathin-wall part of the aircraft engine is printed only by 3D printing, the technological requirements are difficult to meet, mainly because the thin-wall structure with large size of the workpiece has deformation problem after heat treatment, and the roundness and precision of the workpiece are influenced certainly, so that the best turning effect can be achieved by discharging allowance during 3D material increase.

With the development of technologies such as digital modeling and the like, the quality of processed parts can be ensured by adopting modern and traditional processes without expensive special equipment and working hour arrangement, and the direction of processing technology is to improve efficiency and effectively save production and manufacturing cost.

Disclosure of Invention

The invention aims to solve the problems, provides a method for machining an annular large-caliber ultrathin-wall part of an aero-engine by 3D printing and numerical control vertical lathe grinding, and particularly provides a method for machining the annular large-caliber ultrathin-wall part of the aero-engine by turning through numerical control vertical lathe equipment, wherein a special tool clamp and positioning adjustment are adopted, and a programming lathe tool of the numerical control vertical lathe equipment is used for machining and cutting, so that the machining and centering (accurate centering position) are convenient and reliable, the machining period is short, the machining precision is high, and the machining efficiency is high.

The method is realized by the following technical scheme: a machining method of a numerical control vertical lathe mill for an aircraft engine large-caliber ultrathin wall part is characterized in that heat-resistant alloy powder is printed into the aircraft engine large-caliber ultrathin wall part in a 3D mode, redundant thickness of 8-15% of thickness is required to be released during 3D material increase, the heating temperature is 1160-1195 ℃, the heat preservation time is 1-36 hours, and then the aircraft engine large-caliber ultrathin wall part is cooled to room temperature; heat treatment is carried out by adopting a high-frequency heating method, and the heat preservation of the heat treatment is realized by controlling the current (power) of a high-frequency coil; the processed blank is fixed by the following tool and turned by a numerical control vertical lathe, a chassis of the numerical control vertical lathe is formed by modifying a rotary shaft chuck into a rotary centering bottom plate to drive a workpiece to rotate, a rotary Z shaft is vertical to a horizontal plane, a tool bit of the turning tool can be programmed to carry out XY translation and turning of the turning tool by up-and-down precession control, and the tool has the following structure: a centering bottom plate is connected with a main (rotating) shaft of the machine tool on the ground surface; the center of the centering bottom plate is provided with a convex cylinder or a cylinder inner template, the diameter of the cylinder is smaller than the inner diameter of the workpiece cylinder, a rotating shaft of the cylinder is a main shaft of the vertical lathe and is provided with a cylinder inner template lining workpiece, and the outer cylindrical surface of the cylinder is fixed with the inner cylindrical surface of the inner template;

the axis of the workpiece is corrected by using a cylinder or a cylinder inner template, molten hot melting wax is injected between the tool and the workpiece to fix the workpiece, then a turning tool is used for turning an area which is not covered above the cylinder height of the inner template, after more than half of the inner and outer surfaces of the upper end of the workpiece are turned, the workpiece is turned upside down, the lower part of the workpiece which is fixed and reversed is installed by using the method, the workpiece is positioned by using the cylinder or the cylinder inner template and is fixed by using the hot melting wax, and more than half of the inner and outer surfaces of the upper end of the workpiece are turned after installation, namely, the inner and outer surfaces which are originally positioned at the lower end are turned.

The method for correcting the axis of the workpiece by using the cylindrical inner template comprises the following steps that two to three groups of three bolts (parallel to a horizontal plane) are uniformly distributed on the circumference of the cylindrical inner template 1 at 120 degrees, and the three bolts are 12 points, 4 points and 8 points and can be screwed out of the inner template and the screwing-out lengths of the bolts can be adjusted; after a workpiece is sleeved on the inner template, 12-point, 4-point and 8-point bolts are adjusted to extend out of the inner wall of the inner template butting column workpiece and are relatively fixed, the centering bottom plate drives the workpiece to rotate at a low speed, a joint arm fixing dial indicator (dial indicator) contact is used for contacting the wall surface of the workpiece to work, the axis of the workpiece is detected on line, and one to two groups (parallel to the horizontal plane) of three bolts with 12-point, 4-point and 8-point bolt extension lengths distributed uniformly at 120 degrees are adjusted until the axis of the workpiece is consistent with the axis of a machine tool, and then centering is successful.

Furthermore, a second group of three bolts are arranged in the centers of one to two groups of three bolts which are parallel to the horizontal plane and are uniformly distributed at 120 degrees and are 12 points, 4 points and 8 points, the second group of three bolts extend out and are fixed, and then the melted hot melting wax is injected. The cylindrical inner template 1 and the centering bottom plate are required to be machined and centered, and the cylindrical inner template and the centering bottom plate are integrated with a clamp of a vertical lathe.

Further, when the wall holes are formed in the workpiece, the workpiece is wrapped by the outer cylinder template 5 and the cylinder inner template 1 together, and the molten hot melting wax 3 is injected between the outer cylinder template and the inner cylinder template tool and the workpiece (can be injected in multiple stages); the outer template cylinder is of a multi-piece wrapping type and a flexible type, only plays a role of wrapping liquid and fixing wax, and when the wax is solidified at room temperature, the outer template cylinder is dismantled for vertical lathe processing.

Installing a dial indicator (dial indicator), wherein a contact of the dial indicator contacts with the periphery of the edge of the workpiece, and rotating the workpiece and the rotating bolt to observe that the dial indicator does not jump or jumps to the lowest extent; the axle center is centered and then the extension length of the second group of three bolts is fixed (the bolts can be fixed by using a spanner with the same torque).

Only the inner die plate cylinder is used when the workpiece cylinder does not have a wall hole structure.

The outer template cylinder is of a multi-piece wrapping type and a flexible type, only plays a role of wrapping liquid to fix wax, the wax is solidified at room temperature, the outer template cylinder is removed, and the residual wax (hot melting wax, the melting point is 65-100 ℃, and the complete melting temperature is about 80 ℃) existing on the outer wall of the workpiece does not influence the full turning of the outer cylinder of the workpiece (only the wax is easily removed by a turning tool); the height of the inner die plate cylinder is limited and does not exceed half the height of the workpiece.

Has the advantages that: the invention provides a processing method of an annular large-caliber ultrathin-wall part of an aero-engine by 3D printing and numerical control vertical lathe grinding, particularly a method for carrying out turning processing by adopting numerical control vertical lathe equipment, adopting a special tool clamp and positioning adjustment, and machining and cutting by using a programming lathe tool of the numerical control vertical lathe equipment, wherein the processing and alignment (accurate centering position) are convenient and reliable, the processing period is short, the processing precision is high, and the processing efficiency is high. The precision of the finish turning is high, and the precision and the efficiency are both greatly improved. The invention can adjust and align the axis to be positioned and assembled on the numerical control vertical lathe workbench as soon as possible even in a cylindrical structure, is easy to accurately align, improves the processing efficiency, is a processing tool which is far lower than a five-axis processing center in terms of working time cost and processing cost of a vertical lathe, is easy to program, has reliable processing technology, short processing period and high processing precision, and is easy to detect.

Drawings

FIG. 1 is a cylinder workpiece of a wall hole structure and a fin structure, a cylinder with a slight taper slope;

fig. 2 is a schematic structural sectional view of the vertical machine tool linked with the workpiece and the centering base plate during machining (inner and outer die plates).

Detailed Description

According to the processing tool and the processing method shown in the attached drawings, in the processing method of the numerical control vertical lathe grinding of the large-caliber ultrathin-wall part (a cylinder with a fin structure, namely a workpiece 4, shown in figure 1), of the aircraft engine, a large-caliber ultrathin-wall part blank, namely the workpiece 4, with the consistent size on the aircraft engine is printed by using heat-resistant alloy powder (typically nickel-based alloy powder) in a 3D mode, when the 3D printing is used for material increase, the redundant thickness of 8-15% of the thickness is required to be released, and the redundant thickness reaches 0.1-0.4 mm; if the diameter of the workpiece (cylinder) is larger, the thickness redundancy is mainly up to 0.5-0.8 mm. Details such as wall holes need not be redundant. After the blank is subjected to material increase, carrying out a heat treatment process, heating at the temperature of 1160-1195 ℃, keeping the temperature for 1-36 hours, and then cooling to room temperature; the high-frequency heating method is adopted, and the heat preservation is realized by controlling the current (power) of a high-frequency coil; the processed blank is turned by the following tools and a numerical control vertical lathe, a chassis of the numerical control vertical lathe is formed by modifying a rotary shaft chuck into a rotary centering bottom plate 2 to drive a workpiece to rotate, a rotary Z shaft is vertical to a horizontal plane, a tool bit of a turning tool can be programmed to carry out XY translation and turning of the turning tool by precessing up and down, and the tool structure which needs to be adopted is as follows: a centering bottom plate is connected with a main (rotating) shaft of the machine tool on the ground surface; the center of the centering bottom plate is provided with a convex hollow convex circular truncated cone or cylinder (or the center of the centering bottom plate is provided with a hole, and then the hollow convex circular truncated cone or cylinder is installed as a component integrated with the cylinder inner template 1), or an inner template cylinder is additionally arranged and fixed with the convex circular truncated cone or cylinder, or the inner template cylinder is integrated with the convex circular truncated cone, the diameter of the inner template cylinder is smaller than the inner diameter of the workpiece cylinder (the height of the inner template cylinder is lower than the half height of the workpiece), the rotating shaft of the inner template cylinder is a main shaft of the vertical lathe, and the inner template cylinder is arranged to line the workpiece; the workpiece is sleeved on the inner template cylinder.

Correcting the axis of the workpiece by using an inner template cylinder: one to three groups (more groups are also possible) of three bolts which are uniformly distributed at 120 degrees and are parallel to the horizontal plane at different heights are arranged on the cylindrical inner template, and the three bolts are 12 points, 4 points and 8 points and can be screwed out of the inner template and the screwing-out length of the bolts can be adjusted; after a workpiece is sleeved on an inner template, 12-point, 4-point and 8-point bolts are adjusted to extend out of the inner wall of an inner template butting column workpiece and are relatively fixed, a centering bottom plate drives the workpiece to rotate at a low speed, the axis of the workpiece is detected on line by using the wall surface of a joint arm fixing dial indicator (dial indicator) contact work, one to two groups (parallel to the horizontal plane) of three bolts 6 uniformly distributed at 120 degrees are adjusted to be centered successfully when the extension lengths of the 12-point, 4-point and 8-point bolts are consistent with the axis of the workpiece and the axis of a machine tool (if the workpiece is large in mass, a second group of three bolts 6 are arranged in the centers of the one to two groups (parallel to the horizontal plane) of three bolts uniformly distributed at 120 degrees, the second group of three bolts extend out and are fixed, an outer template is used for wrapping the workpiece, and molten hot melting wax 3 is injected between the tool and the workpiece (can be injected in multiple stages), particularly, the workpiece and the inner template are fixed in a strengthening way; only the inner die plate may be used when the workpiece holder does not have a wall hole structure.

There are several methods for correcting the center of the workpiece by using the cylinder inner template, the clearance between the workpiece and the cylinder of the inner template can be adjusted by filling wedge-shaped objects with different thicknesses between the cylinder inner template and the inner wall of the workpiece, and the mode of adjusting the axis is also the mode of adjusting the axis by adjusting the corrected axis of the workpiece and then fixing the inner wall of the workpiece by extending the bolt out of the cylinder inner template.

The workpiece as shown in the figure needs to adopt an outer template cylinder 5, the outer template cylinder is of a multi-piece wrapping type and a flexible type and only plays a role of wrapping liquid and fixing wax, when the wax is solidified when the workpiece is cooled to room temperature, the outer template cylinder is removed, residual wax (hot melting wax, the melting point is 65-100 ℃, and the complete melting temperature is about 80 ℃) exists on the outer wall of the workpiece, the full turning of the outer cylinder of the workpiece is not influenced (as long as the wax is easily removed by a turning tool), and the height of the inner template cylinder is limited and generally does not exceed half of the height of the workpiece; therefore, the turning tool with numerical control programming can be used for turning the area which is not covered above the height of the inner template cylinder, and the turning of the redundancy is finished.

Therefore, the invention can simultaneously deal with the turning of the outer surface of the cylindrical or conical cylindrical workpiece and the turning of the inner wall of the upper part of the inner template cylinder; after turning over more than half of the inner and outer surfaces of the upper end of the workpiece, turning over the workpiece upside down, installing and fixing the lower part of the reversed workpiece by the method, positioning the axis of the workpiece by using the inner template cylinder, fixing the workpiece by using hot melting wax, and turning more than half of the inner and outer surfaces of the upper end of the workpiece after installation (namely turning the inner and outer surfaces which are originally positioned at the lower end by less than half).

Three bolts 6 are uniformly distributed on the inner template cylinder, a dial indicator is installed when the bolts are adjusted, when a contact of the dial indicator contacts the periphery of a workpiece, the dial indicator is observed to have no jump or minimum jump, and finally, the extending lengths of the second group of three bolts are fixed (the bolts can be fastened by using a spanner with the same torque).

Claims

1. A processing method of a numerical control vertical lathe mill for an aircraft engine large-caliber ultrathin-wall part is characterized in that high-temperature-resistant alloy powder is printed into the aircraft engine large-caliber ultrathin-wall part through a material increase technology in a 3D mode, machining allowance of 8-15% of wall thickness is discharged from connecting parts of two ends of a workpiece during 3D material increase, heating is conducted through the following heat treatment technology, the heating temperature is 1160-1195 ℃, the heat preservation time is 1-36 hours, and then the workpiece is cooled to the room temperature; a high-frequency heating method is adopted, and the heat preservation is realized by controlling the current of a high-frequency coil;

the processed blank is fixed and turned by a numerical control vertical lathe through the following tool, the chassis of the numerical control vertical lathe is formed by modifying a rotary shaft chuck into a rotary centering bottom plate to drive a large-caliber ultrathin wall workpiece to rotate, a rotary shaft is a Z shaft and is vertical to a horizontal plane, a lathe tool bit can be programmed to carry out translation of an XZ shaft and turning of an up-and-down feeding control lathe tool, and the tool has the following structure: the centering bottom plate is connected with a chuck of a machine tool spindle in a positioning way; the center of the centering bottom plate is provided with a convex cylindrical inner template, the diameter of the cylindrical inner template is smaller than the minimum inner diameter of the workpiece, the rotating center of the cylindrical inner template is the rotating center of a main shaft of the vertical lathe, a 6-point positioning adjustable device is arranged between the cylindrical inner template and the workpiece, and the cylindrical inner template is matched with the centering bottom plate through an excircle spigot for centering connection and is concentric with the rotating center of a main shaft of the lathe;

positioning the workpiece by using a 6-point positioning adjustable device on the cylindrical inner template to ensure that the rotation center of the workpiece is coincident with or close to the axis line of the fixed cylindrical inner template; when the wall holes are formed in the workpiece, the workpiece is wrapped by the outer cylinder template and the cylinder inner template together, and molten hot melting wax is injected between the outer cylinder template and cylinder inner template tool and the workpiece; the outer cylinder template is of a multi-piece wrapping type or a flexible type and only plays a role of wrapping liquid and fixing wax, and the outer cylinder template is detached when the wax is solidified at room temperature; turning an area which is not covered above the height of the cylinder inner template by using a lathe, and after the turning of the inner surface and the outer surface of the upper end of the workpiece to be processed is finished, integrally turning the workpiece and the cylinder inner template over and fixing the workpiece and the cylinder inner template on a centering bottom plate to continuously process the other end of the workpiece; the surfaces to be machined at the two ends of the workpiece are finished by mounting and fixing by the method, so that the problem that the workpiece is easy to deform and vibrate during turning is solved;

the method for correcting the axis of the workpiece by using the cylindrical inner template comprises the following steps that two groups of three bolts which are uniformly distributed at 120 degrees on the circumference parallel to a horizontal plane are arranged on a cylindrical inner template body, and the three bolts are 12 points, 4 points and 8 points and can be screwed out of the cylindrical inner template and the screwing-out length of the bolts can be adjusted; after the workpiece is sleeved on the cylindrical inner template, adjusting bolts at 12 points, 4 points and 8 points to extend out of the cylindrical inner template to prop against the inner wall of the workpiece to be relatively fixed under the condition that the workpiece is not deformed, slowly driving the workpiece to rotate at a low speed on a machine tool and fixing a dial indicator on a Z axis of the machine tool, and adjusting the extension lengths of the bolts at 12 points, 4 points and 8 points which are uniformly distributed at 120 degrees and parallel to a horizontal plane until the axis of the workpiece is consistent with the axis of the machine tool if the axis of the workpiece is not consistent with the axis of the machine tool by the wall surface of a contact head to be in contact with the work tool to ensure that the centering is successful; after the centering is successful, a precision joint robot arm detection instrument is adopted for detection, the centering bottom plate cylinder inner template and the workpiece are detected, whether the relative position of the workpiece and the tool is in accordance with the original design purpose or not is confirmed again, and if the workpiece and the tool are in accordance with the original design purpose, the centering is successful; and carrying out the next processing.

2. The numerical control vertical lathe grinding method for the large-caliber ultrathin-wall parts of the aircraft engine as claimed in claim 1, wherein only a cylindrical inner template is used when the workpiece has no wall hole structure.

3. The numerical control vertical lathe grinding method for the large-caliber ultrathin-wall parts of the aircraft engine as claimed in claim 1, wherein the heights of the two ends of the cylindrical inner template higher than the workpiece are not more than half of the height of the workpiece.