阅读说明：本技术 一种航空发动机叶片的加工成型方法 (Machining and forming method of aero-engine blade ) 是由 田向洋 武鹏飞 周林 裴聪 陈勇 蔡典祥 刘定坤 唐波 任凤英 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种航空发动机叶片的加工成型方法,属于航空发动机零部件加工技术领域。本发明通过对粗铣工艺进行改进,使刀具分层等高的进行横向加工,避免单层加工时连续螺旋走刀的方式导致叶片颤动过大；可以减少刀具的轴向切削力,有效避免加工过程中随着余量去除导致的叶片刚性不足。在热处理时在叶片底部悬挂重物,可加快叶片内应力的消除,降低处理过程中的因内应力消除而产生的变形量；并且叶片受到重物拉力的方向与自身延伸方向一致,避免因外力作用产生额外的变形量。精铣时则由中间位置下刀向两端进行铣削,并通过渐进式接刀避免下刀处的加工变形,从而有效地解决了铝制叶片加工成型时存在变形量较大,导致合格率较低的问题。(The invention discloses a machining and forming method of an aero-engine blade, and belongs to the technical field of machining of parts of aero-engines. According to the invention, the rough milling process is improved, so that the cutters are transversely processed in a layered and equal height manner, and the phenomenon that the blade vibrates too much due to a continuous spiral feed mode in single-layer processing is avoided; the axial cutting force of the cutter can be reduced, and the problem that the rigidity of the blade is insufficient due to the removal of the allowance in the machining process is effectively avoided. During heat treatment, a heavy object is hung at the bottom of the blade, so that the elimination of the internal stress of the blade can be accelerated, and the deformation generated by the elimination of the internal stress in the treatment process can be reduced; and the direction of the blade under the tension of the heavy object is consistent with the extending direction of the blade, so that the extra deformation caused by the action of external force is avoided. During finish milling, the lower cutter at the middle position is used for milling towards two ends, and the progressive cutter connection is used for avoiding the machining deformation at the lower cutter, so that the problem that the yield is low due to the fact that the deformation is large during the machining and forming of the aluminum blade is effectively solved.)

1. The machining and forming method of the aero-engine blade is characterized by comprising the following steps:

s1: roughly milling the blade, and carrying out layered equal-height transverse processing in the direction from the blade tip to the blade root, and reserving proper rough machining allowance;

s2: stress-relief heat treatment is carried out on the blades, the blades are suspended on a heat treatment clamp, a heavy object is suspended below the blades, and the heat treatment temperature is as follows: 170-180 ℃, and the heat treatment time is as follows: 3-5H;

s3: and (3) finely milling the blade, adopting a middle lower cutter, milling the blade in two directions of the blade tip and the blade root, and using a progressive cutter at the lower cutter.

2. The method for machining and forming an aircraft engine blade according to claim 1, wherein before the step S2, the relevant mathematical function is obtained through data collection of the rough milling allowance and the final deformation amount of the blade in the prior art and modeling analysis.

3. The method for forming an aircraft engine blade according to claim 2, wherein the machining allowance range of the rough milling is as follows: when the thickness is 0.7-0.9 mm, the minimum deformation range is as follows: 0.25 to 0.35 mm.

4. The method of claim 1, wherein in steps S1 and S3, the tenon near the blade root is positioned by a fixture, and the process round platform near the blade tip is naturally clamped by a three-jaw fixture.

5. The method of claim 1, wherein in step S1, the layer distance during the layered machining of the cutter is in the range of 0.3 to 0.5mm, and the direction of the cutter shaft is perpendicular to the normal direction of the curved surface of the blade.

6. The method for machining and forming the aircraft engine blade according to claim 1, wherein in step S2, the tenon of the blade is clamped and suspended, and a process hole is formed in the process circular table to facilitate hanging of a heavy object.

7. The forming method of an aircraft engine blade according to claim 6, wherein in step S2, the weight of the weight is 1.2 to 1.6 times of the self weight of the blade.

8. The method for machining and forming an aircraft engine blade according to any one of claims 1 to 7, wherein in step S3, the error value of the subsequent workpiece is reversely compensated by using a reverse error compensation method according to the deformation data of the finish-milling head.

9. The method of claim 8, wherein in step S3, the machining is performed by small-cut and large-feed machining.

Technical Field

The invention relates to the technical field of machining of parts of an aero-engine, in particular to a machining and forming method of an aero-engine blade.

Background

The aircraft engine is used as the heart of the aircraft, in order to meet various performances of the engine, the materials of parts of the aircraft engine comprise titanium alloy, high-temperature alloy, aluminum alloy, modern composite materials and the like, and the aluminum alloy is widely applied to the parts of the aircraft engine as a material with low density, high specific strength and low heat conductivity coefficient. However, thin-wall parts such as aluminum alloy blades and the like are easy to deform in the machining process, and the qualification rate is extremely low.

At present, the processing technology of the engine compressor blade mainly adopts a composite manufacturing technology, the blade needs to be subjected to rough machining, finish machining and stress relief heat treatment, the blade profile of the aluminum alloy blade has large deformation in the three procedures, the maximum deformation can reach 2.5mm, and the deformation directions are inconsistent.

After rough milling is finished, the middle section of the blade type is easy to deviate and deform, the maximum length can reach 2.5mm, the blade type is arched, deformation trends are inconsistent, the rough milling is generally carried out by 4 layers in order to reduce deformation, and the processing time is long and is about 5 times of that of blades made of other materials with the same size. During stress relief treatment: the parts are horizontally placed in a heat treatment furnace, the stress relief heat treatment temperature is 155 +/-5 ℃, and the heat preservation time is 3 hours. After stress relief is completed, part of the blades have no machining allowance due to deformation during finish milling, and the blades can be directly scrapped. The cutter during finish milling is an D16R1.6 two-tooth round nose milling cutter, the rotating speed is low, the feeding is low, and the blade body is directly processed in place layer by layer. After finishing milling the blade profile, the deformation is mainly torsional deformation of the blade tip section of the blade profile, and the middle section is offset deformation. Therefore, the problem that the aluminum blade of the aero-engine in the prior art has large deformation during processing and forming, which results in low qualification rate

Disclosure of Invention

The invention aims to provide a machining and forming method of an aero-engine blade, and aims to solve the problem that the yield is low due to large deformation when the blade of the conventional aero-engine is machined and formed.

The technical scheme for solving the technical problems is as follows:

the machining and forming method of the aero-engine blade is characterized by comprising the following steps:

s1: roughly milling the blade, and carrying out layered equal-height transverse processing in the direction from the blade tip to the blade root, and reserving proper rough machining allowance;

s2: stress-relief heat treatment is carried out on the blades, the blades are suspended on a heat treatment clamp, a heavy object is suspended below the blades, and the heat treatment temperature is as follows: 170-180 ℃, and the heat treatment time is as follows: 3-5H;

s3: and (3) finely milling the blade, adopting a middle lower cutter, milling the blade in two directions of the blade tip and the blade root, and using a progressive cutter at the lower cutter.

According to the invention, the rough milling process is improved, so that the cutter carries out horizontal machining in a layered mode and the like, the problem that machining allowances at different positions are uneven due to overlarge blade vibration caused by continuous spiral feed in single-layer machining is solved, the axial cutting force of the cutter can be reduced, and the phenomenon that deformation is inconsistent due to insufficient blade rigidity caused by allowance removal in the machining process is effectively avoided. During heat treatment, a heavy object is hung at the bottom of the blade, so that the elimination of the internal stress of the blade can be accelerated, the heat treatment efficiency is improved, and the deformation caused by the elimination of the internal stress in the treatment process is reduced; and the direction of the blade under the tension of the heavy object is consistent with the extending direction of the blade, so that the internal stress of the blade is eliminated, and extra deformation caused by the action of external force is avoided. During finish milling, the lower cutter at the middle position is used for milling towards two ends, and the progressive cutter connection is used for avoiding the machining deformation at the lower cutter, so that the problem that the yield is low due to the fact that the deformation is large during the machining and forming of the aluminum blade is effectively solved.

Further, before step S1, the related mathematical function is obtained by collecting data of the rough milling allowance and the final deformation of the blade in the prior art and by modeling and analyzing.

According to the method, the rough milling allowance and the final deformation of the existing blade are collected and counted, and a linear regression or nonlinear regression parameter and a deformation trend function are made by using data to obtain an optimal machining parameter, so that the deformation is reduced; and a pre-deformation amount is given to stress relief heat treatment during rough milling, so that the deformed blade basin back allowance is more uniform during the stress relief heat treatment.

Further, the machining allowance range of the rough milling is as follows: when the thickness is 0.7-0.9 mm, the minimum deformation range is as follows: 0.25 to 0.35 mm.

According to the invention, the corresponding rough milling allowance in the lowest deformation range is obtained through the deformation trend function, so that the rough milling parameters are correspondingly adjusted, and the deformation of rough milling is reduced by adopting a reverse-thrust method.

Further, in the steps S1 and S3, the tenon near the blade root is positioned by the fixture, and the process round table near the blade tip is naturally clamped by the three-jaw fixture.

The invention can effectively reduce the arch problem of the middle section of the blade caused by too tight tip process through natural clamping of the three-jaw clamp.

Further, in step S1, the pitch range of the blade during the layer-by-layer machining is 0.3 to 0.5mm, and the cutter axis direction is perpendicular to the normal direction of the curved surface of the blade.

According to the invention, the machining amount during rough milling is reasonably planned, the cutter shaft direction is ensured, and excessive local concentrated stress generated in the blade due to excessive rough milling allowance and direction inclination is avoided.

Further, in step S2, the tenon of the blade is clamped and suspended, and the circular truncated cone is provided with a fabrication hole for conveniently suspending a heavy object.

According to the invention, the process holes are formed in the process round table to hang the heavy objects, so that the hung heavy objects can be prevented from sliding off, and the damage to the blades caused by long-time hanging can be avoided.

Further, in step S2, the weight of the weight is 1.2 to 1.6 times the weight of the blade.

The invention limits the weight range of the suspended heavy object, thereby facilitating the blade to eliminate the internal stress of the blade in effective time.

Further, in step S3, the error value of the subsequent workpiece is inversely compensated by using an inverse error compensation method according to the deformation data of the finish milling head.

When in finish machining, after the first deformation data of the same batch of blades are acquired, the corresponding machining program and parameters are adjusted, and the subsequent machined parts are continuously machined by a reverse compensation method, so that the debugging time is conveniently reduced, and the production efficiency is improved.

The invention has the following beneficial effects:

(1) according to the invention, the rough milling process is improved, so that the cutter carries out horizontal processing in a layered mode and the like, the problem that the vibration of the blade is too large to cause uneven processing allowances at different positions in a continuous spiral feed mode during single-layer processing is avoided, the axial cutting force of the cutter can be reduced, and the deformation inconsistency caused by insufficient rigidity of the blade along with the allowance removal in the processing process is effectively avoided; and a pre-deformation amount is given to stress relief heat treatment during rough milling, so that the deformed blade basin back allowance is more uniform during the stress relief heat treatment.

(2) During heat treatment, a heavy object is hung below the blade, so that the elimination of the internal stress of the blade can be accelerated, the heat treatment efficiency is improved, and the deformation caused by the elimination of the internal stress in the treatment process is reduced; and the direction of the blade under the tension of the heavy object is consistent with the extending direction of the blade, so that the internal stress of the blade is eliminated, and extra deformation caused by the action of external force is avoided.

(3) During finish milling, the lower cutter at the middle position is used for milling towards two ends, and the progressive cutter connection is used for avoiding the machining deformation at the lower cutter, so that the problem that the yield is low due to the fact that the deformation is large during the machining and forming of the aluminum blade is effectively solved.

Drawings

FIG. 1 is a schematic view of a feeding path of a tool during rough milling according to the present invention;

FIG. 2 is a schematic view of a blade configuration of a workpiece according to the present invention;

FIG. 3 is a schematic diagram showing the relationship between the rough milling allowance and the deformation amount according to the present invention.

In the figure: 10-a blade; 20-tenon; 30-processing a circular table; 40-cutting tools.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

Examples

A machining and forming method of an aircraft engine blade comprises the following steps:

s1: the blade 10 is roughly milled, layered equal-height transverse machining is carried out in the direction from the blade tip to the blade root, and proper rough machining allowance is reserved. Through improving rough milling process, make the cutter 40 high horizontal processing of layering, avoid the individual layer to add the mode of continuous spiral feed and lead to the blade 10 to shake too big and cause the uneven problem of different positions machining allowance during processing to can reduce the axial cutting force of cutter 40, effectively avoid getting rid of the not consistent problem of deformation that leads to along with the blade 10 rigidity that leads to is not enough along with the allowance in the course of working.

Referring to fig. 2, the left end of the blade 10 is a tenon 20, and the tenon 20 is provided with an assembly circular hole through which the blade 10 is suspended on a fixture during heat treatment; the right end is provided with a technical round table 30 which plays a role in clamping and positioning the blade 10 during processing. The craft circular table 30 is provided with a craft hole for facilitating the thin line to pass through when the blade 10 is subjected to heat treatment, so that a heavy object is hung at the bottom through the thin line.

Before rough milling, data collection is carried out on rough milling allowance and final deformation of the blade 10 in the prior art, a relevant mathematical function is obtained through modeling analysis, namely a linear regression or nonlinear regression parameter and a deformation trend function are made through the data, so that an optimal machining parameter is obtained, and the deformation is reduced. And analyzing the corresponding mathematical function image, and selecting the machining allowance range of rough milling as follows: 0.7-0.9 mm, the corresponding deformation range is minimum at this moment, and is as follows: 0.25 to 0.35 mm. And the parameters and the program of the rough milling are adjusted according to the parameters and the program, and the deformation of the rough milling is reduced by adopting a reverse thrust method.

In step S1, the layer distance range of the cutter 40 during layered machining is 0.3 to 0.5mm, and the cutter axis direction is perpendicular to the normal direction of the curved surface of the blade 10, so that the machining amount during rough milling is reasonably planned, and the cutter axis direction is ensured, thereby avoiding excessive local concentrated stress generated inside the blade 10 due to excessive rough milling allowance and directional inclination. The rough milling cutter 40 adopts a small R-angle double-edge round nose milling cutter, the rotating speed of the cutter 40 is controlled within the range of 9000-12500R/min, and the feeding speed is controlled within the range of 4500-6500 mm/min. In the process of roughly milling the blade profile, reverse compensation is used for giving a reverse compensation value to stress relief heat treatment, and the uniformity of blade profile allowance after stress relief is finished is guaranteed.

S2: stress-relief heat treatment is performed on the blades 10, a plurality of blades 10 are suspended on a heat treatment fixture, and a heavy object is suspended below the blades 10, wherein the heat treatment temperature is as follows: 170-180 ℃, and the heat treatment time is as follows: 3-5H. When in heat treatment, a heavy object is hung below the blade 10, so that the elimination of the internal stress of the blade 10 can be accelerated, the heat treatment efficiency is improved, and the deformation caused by the elimination of the internal stress in the treatment process is reduced; and the direction of the blade 10 which is pulled by the heavy object is consistent with the extending direction of the blade, so that the internal stress of the blade is eliminated, and meanwhile, no extra deformation is generated due to the action of external force. The temperature range of the heat treatment is also 20 ℃ lower than the solution aging temperature of the aluminum alloy blade 10, so that the aluminum blade 10 is not subjected to solution treatment.

In step S2, the tenon 20 of the blade 10 is clamped and suspended, and the process round table 30 is provided with a process hole for conveniently suspending a heavy object. The process holes are formed in the process round table 30 to hang the heavy objects, so that the hung heavy objects can be prevented from sliding off, and the damage to the blade 10 caused by long-time hanging can be avoided. In addition, the weight of the suspended heavy object is 1.2-1.6 times of the dead weight of the blade 10, and the weight range of the suspended heavy object is limited, so that the blade 10 is assisted to eliminate the internal stress of the blade in an effective time conveniently.

S3: the blade 10 is finely milled by using a middle lower cutter, milling is performed in two directions of a blade tip and a blade root, and a progressive cutter is used at the lower cutter. The progressive type cutter connecting device avoids the processing deformation of the lower cutter, thereby effectively solving the problem that the aluminum blade 10 has large deformation during processing and forming, and the qualified rate is low. The processing cutter 40 adopts a special alloy milling cutter for small R-angle aluminum alloy, the rotating speed of the cutter 40 is controlled within the range of 12000-15000R/min, the cutting speed is controlled within the range of 2500-3500R/min, the feed rate is 0.3-0.5 mm/R, the small cutting and large feeding modes are adopted, and the processing time can be shortened by multiple times

In steps S1 and S3, the fixture positions the tenon 20 near the blade root, and the three-jaw fixture naturally clamps the craft circular table 30 near the blade tip, so as to effectively reduce the problem of "camber" of the middle section of the blade 10 caused by too tight tip craft. And applies a pulling force in the direction of the center line in which the blade 10 extends, by the program instructions of the processing equipment. In step S3, after the first deformation data of the same batch of blades 10 is collected, the corresponding processing program and parameters are adjusted, and the subsequent processed parts are further processed by the reverse compensation method, so that the debugging time is reduced, and the production efficiency is improved. And the program packet database is established according to the compensation value, so that the debugging time is reduced.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.