A method for milling a profile of a gamma-TiAl alloy ultrathin blade

Abstract

The present application relates to the field of blade processing, especially to a kind of γ-TIAL alloy ultra-thin blade profile milling processing method, comprising the following steps: S1, the rough milling processing of blade profile, obtain primary workpiece;S2, the air inlet and exhaust edge of blade profile of primary workpiece is processed secondly, obtain secondary workpiece;S3, the semi-finish milling processing of blade profile except air inlet and exhaust edge of secondary workpiece, obtain tertiary workpiece;S4, the finish milling processing of blade profile of tertiary workpiece, obtain fourth workpiece;S5, the polishing treatment of fourth workpiece, obtain finished workpiece.The present application provides a kind of γ-TiAl alloy milling process preferred parameter of difficult deformation material, simultaneously expounds new ultra-thin blade milling processing technology, avoids the machining deformation caused by large cutting force, achieves the purpose of controlling machining deformation.

Description

Technical Field

[0001] This invention relates to the field of blade processing, specifically to a method for milling the profile of an ultrathin γ-TIAL alloy blade. Background Technology

[0002] Blades are typical complex curved surface parts, playing a crucial role in energy conversion in aero-engines and serving as the "heart" of the engine. New ultra-thin blades are characterized by bending, width, sweeping, twisting, and thinness; the thickness of the inlet and outlet edges is generally less than half that of conventional blades—the minimum radius at the leading and trailing edges is approximately 0.1–0.5 mm. The manufacturing process of these new ultra-thin blades requires extremely high surface precision, with a design profile error range of ±0.05 mm and a twist angle of less than ±10′. γ-TiAl alloy is a difficult-to-deform metallic material, characterized by high cutting force per unit area, high cutting temperature, high chemical reactivity, severe flank friction, and poor surface integrity. This makes it highly susceptible to tool wear and chipping, and the machined surface is prone to cracking, peeling, and even surface fragmentation. Significant deformation and springback are also common during machining, making dimensional control difficult.

[0003] Compared to milling common blade profiles made of common materials, the milling of novel ultrathin blades made of γ-TiAl alloy involves greater cutting forces and higher residual stress, making it difficult to achieve the required surface accuracy. Even CNC semi-finishing combined with manual grinding cannot meet the design drawings. This is mainly because manual grinding lacks coolant, relies solely on templates to control the blade cross-sectional shape, and is highly dependent on human factors, resulting in low surface accuracy, high waviness, susceptibility to burning, and unstable quality. In particular, the accuracy between blade cross-sections and the leading and trailing edges cannot be guaranteed, making it difficult to meet the requirements for wall thickness and precision control of ultrathin blades. Reducing the cutting force and residual stress during milling, and strengthening the prevention and control of deformation during the machining process, are among the challenges in machining novel ultrathin blades made of γ-TiAl alloy. Currently, no methods for controlling the cutting force and residual stress during the milling of novel ultrathin blades made of γ-TiAl alloy have been reported. Therefore, developing a milling method that can control and prevent deformation during the milling of novel ultrathin blades made of γ-TiAl alloy and improve the product qualification rate remains of great significance. Summary of the Invention

[0004] To address the problem of difficulty in controlling and preventing deformation during milling of novel ultrathin blades made of γ-TiAl alloy in existing technologies, this invention provides a method for milling the profile of ultrathin blades made of γ-TiAl alloy.

[0005] A method for milling the profile of an ultrathin γ-TIAL alloy blade includes the following steps:

[0006] S1, one rough milling operation on the blade profile to obtain one workpiece;

[0007] S2, perform secondary processing on the air intake and exhaust edges of the primary workpiece to obtain the secondary workpiece;

[0008] S3, perform semi-finish milling on the blade surface of the secondary workpiece except for the inlet and outlet sides to obtain the tertiary workpiece;

[0009] S4, perform precision milling on the blade profile of the third workpiece to obtain the fourth workpiece;

[0010] S5, polish the workpiece four times to obtain the finished workpiece.

[0011] Preferably, in S1, the rough milling is performed using layered milling and a small depth of cut and a large spacing cutting method; wherein, the feed per tooth is 0.1 to 0.15 mm / z, the milling width is 2 to 3 mm, and the milling depth is 0.1 to 0.5 mm.

[0012] Preferably, in S1, three-axis single-sided milling is used for rough milling, and the other side of the blade is supported by a support fixture.

[0013] Preferably, the support fixture includes a short journal clamping device, a support device, a long journal clamping device, and a base. The short journal clamping device and the long journal clamping device are disposed opposite to each other on the base, and the support device is disposed between the short journal clamping device and the long journal clamping device. In use, the blade is placed on the support device, and both ends of the blade abut against the short journal clamping device and the long journal clamping device, respectively.

[0014] Preferably, in S2, the secondary machining includes semi-finish milling and finish milling, both of which are performed using a row-by-row fixed-axis machining method;

[0015] In the semi-finish milling process, the feed rate per tooth is 0.1 to 0.15 mm / z, the milling width is 2 to 3 mm, and the milling depth is 0.1 to 0.3 mm.

[0016] During precision milling, the feed rate per tooth is 0.15–0.2 mm / z, the milling width is 0.5–0.6 mm, and the milling depth is 0.3–0.4 mm.

[0017] Preferably, in S2, during the processing, the transition position between the inlet and outlet sides and the blade profile is controlled simultaneously, the inlet and outlet side areas are clearly distinguished, and the extension to the blade profile area is controlled within 0.1mm.

[0018] Preferably, in S3, the semi-finish milling of the blade profile is performed using a small cutting amount and rapid feed method; wherein, the milling width is 2-3 mm, the milling depth is 0.1-0.3 mm, and the feed per tooth is 0.1-0.15 mm / z.

[0019] Preferably, the row spacing during semi-finish milling of the blade profile is twice that during finish milling of the blade profile.

[0020] Preferably, in S4, the precision milling of the blade shape of the three parts adopts the method of "small depth of cut, small spacing, and fast feed"; wherein, the milling width is 0.3 to 0.4 mm, the milling depth is 0.3 to 0.4 mm, and the feed per tooth is 0.15 to 0.2 mm / z.

[0021] Preferably, in S5, the surface roughness Ra of the finished workpiece is ≤0.4μm.

[0022] This invention discloses a milling method for ultra-thin γ-TiAl alloy blades. This method involves milling the inlet and outlet edges and the blade profile separately, with the blade profile supported by a single-sided milling fixture on the other side. Simultaneously, the machining parameters for rough milling, semi-finish milling, and finish milling steps are selected within an optimal range. By employing separate machining of the inlet and outlet edges and the blade profile, the method aims to prevent and control significant deformation of the blade profile. Combined with light polishing of the blade profile, this method further controls the deformation of the γ-TiAl alloy ultra-thin blade profile during machining. Ultimately, the leading and trailing edge radii, design profile, torsion angle, and surface roughness of the part all meet the design requirements.

[0023] Furthermore, the rough milling process adopts layered milling, small depth of cut, and large line spacing cutting method. During the machining process, three-axis single-sided milling is used, and a support fixture is used on the other side of the blade for support, which takes into account both cutting efficiency and avoids causing large deformation, while saving machining costs.

[0024] Furthermore, the intake and exhaust edge milling employs a row-by-row fixed-axis machining method, meaning that the tool axis direction remains fixed for each row, while the tool axis directions of adjacent cutting rows differ. This method helps improve surface quality. The cutting rows between the intake and exhaust edges and the blade profile avoid repeated cutting, while simultaneously controlling the transition position between the intake and exhaust edges and the blade profile, clearly distinguishing the intake and exhaust edge areas.

[0025] Furthermore, semi-finish milling employs a method of small cutting depth and rapid feed to avoid machining deformation caused by large cutting forces, thereby achieving the goal of controlling machining deformation caused by residual stress.

[0026] Furthermore, the finish milling process employs small milling cuts to reduce cutting forces, resulting in lower residual stress on the part surface and achieving dimensional control. Considering the characteristics of ultra-thin blades, a fixed-axis machining method is considered in each finish milling pass, achieving multi-axis machining with minimal tool axis control, effectively improving machining stability and surface quality. Attached Figure Description

[0027] Figure 1 This is a schematic flowchart of a method for milling the surface of an ultrathin γ-TIAL alloy blade according to the present invention.

[0028] Figure 2 A schematic diagram for supporting the tooling;

[0029] Figure 3 A partial structural diagram of the tooling;

[0030] Figure 4 This is a schematic diagram of the rough milling process for blade-shaped machining.

[0031] Figure 5 A schematic diagram of the intake and exhaust edge milling machining method - row-fixed axis;

[0032] Figure 6 This is a schematic diagram of a semi-finish milling process for blade basins.

[0033] Figure 7 This is a schematic diagram of a semi-finish milling blade back milling process;

[0034] Figure 8 This is a schematic diagram of the precision milling process for blade basins;

[0035] Figure 9 This is a schematic diagram of the precision milling process for the blade back.

[0036] In the diagram: 1. Short journal clamping device; 11. Clamping seat; 12. Pressure plate; 13. Auxiliary rod; 14. Clamping bolt; 15. Clamping spring; 16. Clamping nut; 2. Support device; 21. Clamping bolt; 22. Cover plate; 23. Support; 24. Support column; 25. Adjusting slider; 26. Positioning bolt; 27. Adjusting spring; 3. Long journal clamping device; 4. Base. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0038] This invention discloses a method for milling the profile of ultrathin γ-TIAL alloy blades, the main process of which is as follows: Figure 1 As shown, the blade profile rough milling → blade inlet and outlet edge machining → blade semi-finish milling → blade finish milling → light polishing process includes the following steps:

[0039] Step 1: Rough milling of the blade profile. The machining process uses a three-axis single-sided milling machine, with a support fixture used on the other side of the blade (see details). Figure 2 , 3 Rough milling employs layered milling with small depth of cut and large line spacing (see details). Figure 4 This approach balances cutting efficiency with avoiding significant deformation, while also saving on processing costs.

[0040] The support fixture includes a short journal clamping device 1, a support device 2, a long journal clamping device 3, and a base 4. The short journal clamping device 1 and the long journal clamping device 3 are arranged opposite each other on the base 4, and the support device 2 is arranged between the short journal clamping device 1 and the long journal clamping device 3. In use, the blade is placed on the support device 2, and the two ends of the blade abut against the short journal clamping device 1 and the long journal clamping device 3 respectively.

[0041] The short journal clamping device 1 and the long journal clamping device 3 have the same structure. Taking the short journal clamping device 1 as an example, it includes a clamping seat 11, a pressure plate 12, an auxiliary rod 13, a clamping bolt 14, a clamping spring 15, and a clamping nut 16. The clamping seat 11 is fixed on the base 4 and includes an L-shaped horizontal plate and a vertical plate. One end of the pressure plate 12 is fixed to the horizontal plate of the clamping seat 11 through the auxiliary rod 13, and the other end is suspended above the vertical plate. One end of the clamping bolt 14 is connected to the horizontal plate, and the other end passes through the pressure plate 12 and is connected to the clamping nut 16. The clamping spring 15 is sleeved on the clamping bolt 14 and is located between the horizontal plate and the pressure plate 12. In use, the short shaft of the blade is placed between the pressure plate 12 and the vertical plate, and the blade is fixed by rotating the clamping bolt 14.

[0042] The support device 2 includes clamping bolts 21, a cover plate 22, a support 23, a support column 24, an adjusting slider 25, a positioning bolt 26, and an adjusting spring 27. The support 23 is fixed to the base 4 and has a vertical groove. The cover plate 22 is positioned at the left opening of the groove via the clamping bolts 21. The adjusting slider 25 is slidably disposed inside the groove. The adjusting spring 27 is located at the bottom of the adjusting slider 25, and the extension axis of the adjusting spring 27 is coaxial with the sliding axis of the adjusting slider 25. The positioning bolt 26 penetrates the side wall of the support 23 and abuts against the side wall of the adjusting slider 25 to position the adjusting slider 25. The support column 24 is located at the top of the adjusting slider 25 for supporting and placing the blades.

[0043] Milling method: layered milling, small depth of cut, large row spacing;

[0044] Cutting tool: Ruifeng K44 alloy coated circlip cutter with a fillet radius of 0.5mm and a diameter of 10mm;

[0045] Rough machining allowance: 0.8mm;

[0046] Cooling method: Emulsion cooling (Tairunite CCF-10, 6%);

[0047] The preferred range is a feed rate of 0.1–0.15 mm / z per tooth, for example: 0.1 mm / z, 0.11 mm / z, 0.12 mm / z, 0.13 mm / z, 0.14 mm / z, 0.15 mm / z;

[0048] The preferred range is a milling speed of 35–45 m / min, for example: 35 m / min, 40 m / min, 45 m / min;

[0049] Preferred milling width is 2-3mm, for example: 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm;

[0050] The preferred range is a milling depth of 0.1 to 0.5 mm, for example: 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm.

[0051] Step 2: Machining of the air intake and exhaust edges (semi-finish milling + finish milling). The air intake and exhaust edge milling employs a segmented fixed-axis machining method (see details). Figure 5 This method involves keeping the tool axis direction fixed for each cut, while the tool axis directions of adjacent cuts differ. This approach is beneficial for improving surface quality. The cuts between the inlet / outlet edges and the blade profile avoid repeated cutting. Simultaneously, the transition position between the inlet / outlet edges and the blade profile is controlled, clearly distinguishing the inlet / outlet edge area, and extending it to the blade profile area is controlled within 0.1mm.

[0052] (1) Semi-finish milling of intake and exhaust sides

[0053] Tool axis control method: Separate axis control

[0054] Cutting tool: Ruifeng Cutting Tool Co., Ltd. K44 alloy coated ball end mill, 7mm in diameter;

[0055] Machining allowance: 0.3mm;

[0056] Processing removal amount: 0.5mm;

[0057] Cooling method: Emulsion cooling (Tairunite CCF-10, 6%);

[0058] The preferred range is a feed rate of 0.1–0.15 mm / z per tooth, for example: 0.1 mm / z, 0.12 mm / z, 0.13 mm / z, 0.14 mm / z, 0.15 mm / z;

[0059] The preferred range is a milling speed of 35–45 m / min, for example: 35 m / min, 40 m / min, 45 m / min;

[0060] Preferred milling width is 2-3mm, for example: 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm;

[0061] The preferred milling depth is 0.1–0.3 mm, for example: 0.1 mm, 0.2 mm, 0.3 mm;

[0062] (2) Precision milling of intake and exhaust edges

[0063] Tool axis control method: Separate axis control

[0064] Cutting tool: Ruifeng Cutting Tool Co., Ltd. K44 alloy coated ball end mill, 7mm in diameter;

[0065] Processing removal amount: 0.3mm;

[0066] Cooling method: Emulsion cooling (Tairunite CCF-10, 6%);

[0067] The preferred range is a feed rate of 0.15–0.2 mm / z per tooth, for example: 0.15 mm / z, 0.16 mm / z, 0.17 mm / z, 0.18 mm / z, 0.19 mm / z, 0.2 mm / z;

[0068] The preferred range is a milling speed of 40–50 m / min, for example: 40 m / min, 45 m / min, 50 m / min;

[0069] The preferred milling width is 0.5–0.6 mm, for example: 0.5 mm, 0.6 mm;

[0070] The preferred milling depth is 0.3–0.4 mm, for example: 0.3 mm, 0.4 mm;

[0071] Step 3: Semi-finish milling of the blade profile (excluding the inlet and outlet edges). Semi-finish milling employs a small cutting depth and rapid feed method (see...). Figure 6 , 7 This method avoids machining deformation caused by large cutting forces, thereby controlling machining deformation caused by residual stress. The blade profile is machined using single-sided milling, with the other end supported by a tooling fixture.

[0072] Milling method: small depth of cut, fast feed, and the line spacing is twice that of finish milling;

[0073] Cutting tool: Ruifeng Cutting Tool Co., Ltd. K44 alloy coated ball end mill, 7mm in diameter;

[0074] Cooling method: Emulsion cooling (Tairunite CCF-10, 6%);

[0075] Machining allowance: 0.3mm;

[0076] Processing removal amount: 0.5mm;

[0077] The preferred range is a feed rate of 0.1–0.15 mm / z per tooth, for example: 0.1 mm / z, 0.12 mm / z, 0.13 mm / z, 0.14 mm / z, 0.15 mm / z;

[0078] The preferred range is a milling speed of 35–45 m / min, for example: 35 m / min, 40 m / min, 45 m / min;

[0079] Preferred milling width is 2-3mm, for example: 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm;

[0080] The preferred milling depth is 0.1–0.3 mm, for example: 0.1 mm, 0.2 mm, 0.3 mm;

[0081] Step four, finish milling of the blade shape. The finish milling process uses small milling cuts (see...). Figure 8 , 9 This reduces cutting forces, resulting in lower residual stress on the part surface and achieving dimensional control. Considering the characteristics of ultra-thin blades, a fixed-axis machining method is considered in each precision milling pass, achieving multi-axis machining with minimal tool axis control, effectively improving machining stability and surface quality. The blade profile is machined using single-sided milling with support on the other side, further reducing dimensional deformation caused by residual machining stress.

[0082] Milling method: small depth of cut, small pass spacing, fast feed;

[0083] Cutting tool: Ruifeng Cutting Tool Co., Ltd. K44 alloy coated ball end mill, 7mm in diameter;

[0084] Cooling method: Emulsion cooling (Tairunite CCF-10, 6%);

[0085] Processing removal amount: 0.3mm;

[0086] The preferred range is a feed rate of 0.15–0.2 mm / z per tooth, for example: 0.15 mm / z, 0.16 mm / z, 0.17 mm / z, 0.18 mm / z, 0.19 mm / z, 0.2 mm / z;

[0087] The preferred range is a milling speed of 40–50 m / min, for example: 40 m / min, 45 m / min, 50 m / min;

[0088] The preferred milling width is 0.3–0.4 mm, for example: 0.3 mm, 0.4 mm;

[0089] The preferred milling depth is 0.3–0.4 mm, for example: 0.3 mm, 0.4 mm;

[0090] Step 5: Light polishing treatment of the novel ultra-thin blade. After polishing the precision-milled blade, a surface roughness Ra≤0.4μm is obtained.

[0091] Example 1:

[0092] A method for milling the profile of the first-stage stator blade of a certain aircraft made of γ-TiAl alloy, the method comprising the following steps:

[0093] (1) Using γ-TiAl alloy as raw material, after the blade journal is machined to a qualified standard, install the blade milling special support fixture.

[0094] (2) Position and clamp the blade from step (1) and perform rough milling; feed per tooth 0.12mm / z, milling speed 35m / min, milling width 2.4mm, milling depth 0.5mm; layer milling, small depth of cut, large spacing cutting method, allowance 0.8mm;

[0095] (3) Mill the air intake and exhaust edges in step (2), with the cutter axis controlled by the fixed axis of the row; feed per tooth 0.13mm / z, milling speed 35m / min, milling width 2.2mm, milling depth 0.1mm; mill the air intake and exhaust edges to size.

[0096] (4) Use the blades in step (3) for semi-finish milling, with a feed per tooth of 0.12 mm / z, a milling speed of 40 m / min, a milling width of 2.4 mm, and a milling depth of 0.1 mm; small depth of cut, fast feed, and a row spacing that is twice that of finish milling, with a allowance of 0.3 mm;

[0097] (5) Use the blade from step (4) for fine milling, with a feed per tooth of 0.16 mm / z, a milling speed of 45 m / min, a milling width of 0.5 mm, and a milling depth of 0.1 mm; use a small depth of cut, a small spacing, and a fast feed to process the blade to the final design size.

[0098] (6) Use the precision milling blade shape in step (5) to perform light polishing to obtain a part with qualified surface roughness.

[0099] This invention discloses a novel milling method for ultrathin γ-TiAl alloy blades, providing optimized parameters for the milling process and outlining a novel milling technique for ultrathin blades. This method avoids machining deformation caused by large cutting forces, thus achieving the goal of controlling machining deformation. Using this method, not only can novel ultrathin γ-TiAl alloy blades with acceptable dimensions be produced, but the surface roughness and morphology also meet design requirements.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A method for milling the profile of an ultrathin γ-TIAL alloy blade, characterized in that, Includes the following steps: S1, one rough milling operation on the blade profile to obtain one workpiece; The rough milling process employs layered milling and a small depth of cut with a large spacing. The feed per tooth is 0.1–0.15 mm / z, the milling width is 2–3 mm, and the milling depth is 0.1–0.5 mm. During rough milling, a three-axis single-sided milling method is used, and the other side of the blade is supported by a support fixture. The support fixture includes a short journal clamping device, a support device, a long journal clamping device, and a base. The short journal clamping device and the long journal clamping device are arranged opposite to each other on the base, and the support device is arranged between the short journal clamping device and the long journal clamping device. In use, the blade is placed on the support device, and the two ends of the blade abut against the short journal clamping device and the long journal clamping device respectively. S2, perform secondary processing on the inlet and outlet edges of the blade-shaped primary workpiece to obtain a secondary workpiece; Among them, the intake and exhaust edge milling adopts the row-fixed axis machining method, and the secondary machining includes semi-finish milling and finish milling, all of which are carried out using the row-fixed axis machining method. In the semi-finish milling process, the feed rate per tooth is 0.1 to 0.15 mm / z, the milling width is 2 to 3 mm, and the milling depth is 0.1 to 0.3 mm. During finish milling, the feed rate per tooth is 0.15–0.2 mm / z, the milling width is 0.5–0.6 mm, and the milling depth is 0.3–0.4 mm. During the processing, the transition position between the inlet and outlet edges and the blade profile is controlled simultaneously, clearly distinguishing the inlet and outlet edge areas, and extending to the blade profile area within 0.1mm; S3, perform semi-finish milling on the blade surface of the secondary workpiece except for the inlet and outlet edges to obtain the tertiary workpiece; S4, perform precision milling on the blade profile of the third workpiece to obtain the fourth workpiece; S5, polish the workpiece four times to obtain the finished workpiece.

2. The method for milling the surface of γ-TIAL alloy ultrathin blades according to claim 1, characterized in that, In S3, the semi-finish milling of the blade profile is carried out using a small cutting amount and rapid feed method; the milling width is 2~3mm, the milling depth is 0.1~0.3mm, and the feed per tooth is 0.1~0.15mm / z.

3. The method for milling the surface of ultrathin γ-TIAL alloy blades according to claim 2, characterized in that, The row spacing in semi-finish milling of blades is twice that in finish milling of blades.

4. The method for milling the surface of ultrathin γ-TIAL alloy blades according to claim 1, characterized in that, In S4, the finish milling of the blade shape of the three parts adopts the method of "small depth of cut, small spacing, and fast feed"; the milling width is 0.3~0.4mm, the milling depth is 0.3~0.4mm, and the feed per tooth is 0.15~0.2mm / z.

5. The method for milling the profile of ultrathin γ-TIAL alloy blades according to claim 1, characterized in that, In S5, the surface roughness Ra of the finished workpiece is ≤0.4μm.

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