A process for reducing milling marks on an aeroengine inlet cowl strut

Abstract

The present application belongs to the field of aero-engine parts production, and particularly relates to a process method for reducing milling vibration marks of an aero-engine inlet casing support plate. The specific method is as follows: a clamp is designed, the clamp is installed on a machine tool, a part is placed and locked on the clamp, a 4mm allowance is reserved for milling based on the final surface of the part, the remaining machining amount of all support plates is unified, a layered machining method is adopted, the part support plate leading edge is milled with a 1mm cutting depth per tool, after the final machining is completed, one more tool is used for re-machining according to the final size of the part to remove the tool allowance. The present application changes the traditional part clamping and positioning method, solves the problem of poor rigidity of the part machining in the ordinary clamping mode, reduces the machining stress, completely eliminates the part machining tool allowance, improves the machining quality of the support plate, and at the same time eliminates more than 80% of the machining vibration marks and reduces the rework rate.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine component manufacturing, specifically relating to a process method for reducing vibration marks during milling of aero-engine intake casing support plates. Background Technology

[0002] This invention relates to improving the machining quality of a type of aero-engine component. The intake casing is a key component of the aero-engine fan section, used to regulate the airflow entering the aero-engine. The functional characteristics of this component result in poor local rigidity, leading to significant tool deflection during milling of the support plate's leading edge. Furthermore, the surface quality of the part is poor, with numerous machining marks, affecting its appearance and service life. Additionally, due to structural issues, the support plate is suspended in a suspended position, and the significant differences in the support plate's profile prevent the part from being stably clamped and fixed.

[0003] Prior to this invention, attempts were made to enhance the clamping rigidity of parts using rigid auxiliary support positioning fixtures and other methods, but these methods failed to meet the requirements due to significant differences in the position and size of the support plates of the parts. This problem has remained unsolved. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a process method for reducing vibration marks during milling of the intake casing support plate of an aero-engine.

[0005] The technical solution of this invention is: A process for reducing vibration marks during milling of the intake casing support plate of an aero-engine includes the following steps: Step (1) Design the fixture, install the fixture on the machine tool, place the parts and lock them on the fixture; Step (2) Using the final surface of the part as a reference, leave a 4mm allowance for milling. Unify the remaining machining amount of all support plates and use a layered machining method to mill the front edge of the support plate of the part with a depth of cut of 1mm per cut. Step (3) After the final machining is completed, perform one more cut according to the final dimensions of the part to remove the allowance for tool deflection; The main body of the fixture adopts a ring-shaped parts fixture structure design, comprising three parts: a base, a positioning mechanism, and a clamping mechanism. The base includes a fixture base, a pressure alarm assembly, an accumulator, a main clamping pressure gauge, a hydraulic power source interface, an input pressure gauge, an air source inlet, a quick-release lifting interface, a pressure reducing valve, and a zero-point positioner. The positioning mechanism includes a multi-point floating support mechanism, a single-point floating support mechanism, and a positioning ring. The clamping mechanism is a hydraulic pressure plate. The base has a hoisting function and can be quickly connected to the machine tool via a zero-point positioner. The pressure alarm assembly is mounted on the fixture base with screws. Multiple hydraulic pressure plates are set and evenly distributed on the outer side of the part mounting edge. Multiple multi-point floating support mechanisms are set at the corresponding support plate positions. The single-point floating support mechanism and accumulator are distributed at the inner ring of the part, and the accumulator is set between the hydraulic pressure plate and the multi-point floating support mechanism. The main clamping pressure gauge, hydraulic source interface, input pressure gauge, air source input port and pressure reducing valve are distributed in parallel and installed at the lower end of the fixture base. Three quick-installation hoisting interfaces are evenly distributed on the outermost side of the fixture base. The positioning ring is coaxially distributed with the fixture base and fixed on the fixture base.

[0006] Furthermore, in the above-mentioned process for reducing vibration marks during milling of the intake casing support plate of an aero-engine, the preferred embodiment is that the multi-point floating support mechanism consists of multiple elastic floating positioning pins, which are side-locked by fastening blocks on the side, enabling conformal support for uncertain curved surfaces. Fifteen pins are set at the corresponding support plate positions for direct support of the support plate; and six single-point floating support mechanisms are set for supporting the inner ring of the intake casing.

[0007] Furthermore, in the above-mentioned process method for reducing vibration marks during milling of the intake casing support plate of an aero-engine, the preferred embodiment is that nine zero-point positioners are provided; and eight hydraulic pressure plates are provided for clamping and fixing the parts.

[0008] Furthermore, in the above-mentioned process for reducing vibration marks during milling of the intake casing support plate of an aero-engine, the preferred embodiment is as follows: a hydraulic power source is connected via a hydraulic power source interface to achieve oil supply and return; the input oil pressure is displayed via an input pressure gauge; the accumulator contains a nitrogen spring and replenishing oil, which can be replenished when the oil pressure inside the fixture is insufficient; an air source is connected via an air source input port to achieve pneumatic control auxiliary support; and the internal pressure of the fixture is adjusted via a pressure reducing valve.

[0009] Advantages and beneficial effects of the present invention: 1. Based on the welding deformation of the support plate, the present invention adjusts the machining allowance of each milling operation to reduce the amount of material processed each time, thereby reducing the cutting force and the stress on the support plate during machining.

[0010] 2. This invention changes the traditional part clamping and positioning method, solves the problem of poor rigidity when parts are processed by ordinary clamping methods, reduces processing stress, completely eliminates tool deflection during part processing, improves the processing quality of support plates, eliminates more than 80% of processing vibration marks, reduces rework rate, and can save about 3,000 yuan in processing costs per engine. Attached Figure Description

[0011] Figure 1 A schematic diagram showing the machining location of the intake casing support plate; Figure 2A schematic diagram of the tool path for a milling program on a part; Figure 3 This is a schematic diagram of the fixture model; Figure 4 This is a schematic diagram of the fixture structure; Figure 5 This is a schematic diagram of a multi-point floating support mechanism; In the diagram, 1-clamp base; 2-hydraulic pressure plate; 3-multi-point floating support mechanism; 4-pressure alarm assembly; 5-single-point floating support mechanism; 6-accumulator; 7-main clamping pressure gauge; 8-hydraulic source interface; 9-input pressure gauge; 10-air source input port; 11-quick-install hoisting interface; 12-pressure reducing valve; 13-zero point positioner; 14-positioning ring. Detailed Implementation

[0012] The following detailed description of specific embodiments of the present invention, in conjunction with the accompanying drawings and examples, is intended to illustrate the present invention but should not be construed as limiting its scope. Example 1

[0013] like Figure 3 , 4 As shown, the fixture body used in this embodiment adopts a ring-shaped parts fixture structure design, which includes three parts: a base, a positioning mechanism, and a clamping mechanism. It includes a fixture base 1, a pressure alarm assembly 4, an accumulator 6, a main clamping pressure gauge 7, a hydraulic power source interface 8, an input pressure gauge 9, an air source input port 10, a quick-release lifting interface 11, a pressure reducing valve 12, and a zero-point positioner 13. The positioning mechanism includes a multi-point floating support mechanism 3, a single-point floating support mechanism 5, and a positioning ring 14. The clamping mechanism is a hydraulic pressure plate 2. The base has a hoisting function and can be quickly connected to the machine tool via nine zero-point positioners 13; the pressure alarm assembly 4 is mounted on the fixture base 1 with screws; eight hydraulic pressure plates 2 are evenly distributed on the outer side of the part mounting edge; and 15 multi-point floating support mechanisms 3 are set at the corresponding support plate positions. Figure 5 As shown, the multi-point floating support mechanism consists of multiple elastic floating positioning pins, which are side-fixed and locked by the fastening blocks on the side. The single-point floating support mechanism 5 and the accumulator 6 are distributed in the inner ring of the part, and the accumulator 6 is set between the hydraulic pressure plate 2 and the multi-point floating support mechanism 3. There are 6 single-point floating support mechanisms 5. The main clamping pressure gauge 7, hydraulic source interface 8, input pressure gauge 9, air source input port 10 and pressure reducing valve 12 are distributed in parallel and installed at the lower end of the clamp base 1. Three quick-installation lifting interfaces 11 are evenly distributed on the outermost side of the clamp base 1. The positioning ring 14 is coaxially distributed with the clamp base 1 and fixed on the clamp base 1.

[0014] In this embodiment, the milling location of the aero-engine intake casing support plate is the leading edge of the support plate, such as... Figure 1As shown, since the support plate is welded to the outer ring of the part, the deformation of different parts is inconsistent, and the maximum allowance can reach 5mm. The traditional solution is to directly process it to the final size, which results in excessive processing. Therefore, in this invention, the processing solution for this position is adjusted to layered processing. The specific processing method is as follows: Step 1: Install the above fixture on the machine tool using the zero-point positioner 13; Step 2: Place the part on the fixture so that the reference plane of the part contacts the upper surface of the fixture positioning ring 14; Step 3: In the free state, check the gap between the reference surface of the part and the upper surface of the fixture positioning ring 14. If there is a gap, use a feeler gauge to level it. Step 4: Align the cylindrical surface of the part to make the part coaxial with the fixture, apply hydraulic pressure to the fixture, and drive the hydraulic pressure plate 2 of the fixture to fix the part on the fixture; Step 5: Supply oil to the single-point floating support mechanism 5 of the fixture to drive its inner ring supporting the part; Step 6: Supply air to the multi-point floating support mechanism 3 of the fixture to lock the mechanism and complete the support of the support plate; Step 7: Retrieve the milling program, leave a 4mm allowance for milling, and unify the remaining machining amount of all support plates; Step 8: Retrieve the milling program, leaving a 3mm allowance, and complete the milling of the leading edge of the part's support plate. Figure 2 The diagram shown is a schematic of the tool path. Select the milling program and complete the milling of the front edge of the support plate of the part, leaving a 2mm allowance. Retrieve the milling program and complete the milling of the front edge of the support plate of the part, leaving a 1mm allowance. Retrieve the milling program and complete the milling of the leading edge of the support plate according to the final dimensions; Step 9: After the final machining is completed, run the program again according to the final dimensions of the part to remove the deflection amount.

Claims

1. A process for reducing vibration marks during milling of the intake casing support plate of an aero-engine, characterized in that, Includes the following steps: Step (1) Design the fixture, install the fixture on the machine tool, place the parts and lock them onto the fixture; Step (2) Using the final surface of the part as a reference, leave a 4mm allowance for milling. Unify the remaining machining amount of all support plates and use a layered machining method to mill the front edge of the support plate of the part with a depth of cut of 1mm per cut. Step (3) After the final machining is completed, perform one more cut according to the final dimensions of the part to remove the allowance for tool deflection; The main body of the fixture adopts a ring-shaped parts fixture structure design, which includes a base, a positioning mechanism, and a clamping mechanism. The base includes a fixture base (1), a pressure alarm assembly (4), an accumulator (6), a main clamping pressure gauge (7), a hydraulic power source interface (8), an input pressure gauge (9), an air source input port (10), a quick-installation hoisting interface (11), a pressure reducing valve (12), and a zero-point positioner (13). The positioning mechanism includes a multi-point floating support mechanism (3), a single-point floating support mechanism (5), and a positioning ring (14). The clamping mechanism is a hydraulic pressure plate (2). The base has a hoisting function and can be quickly connected to the machine tool through the zero point positioner (13); the pressure alarm assembly (4) is installed on the fixture base (1) by screws; multiple hydraulic pressure plates (2) are set and evenly distributed on the outside of the part mounting edge; multiple multi-point floating support mechanisms (3) are set at the corresponding support plate positions; single-point floating support mechanisms (5) and accumulators (6) are distributed at the inner ring of the part, and the accumulators (6) are set between the hydraulic pressure plates (2) and the multi-point floating support mechanisms (3); the main clamping pressure gauge (7), hydraulic source interface (8), input pressure gauge (9), air source input port (10) and pressure reducing valve (12) are distributed in parallel and installed at the lower end of the fixture base (1); three quick-installation hoisting interfaces (11) are evenly distributed on the outermost side of the fixture base (1); the positioning ring (14) is coaxially distributed with the fixture base (1) and fixed on the fixture base (1); The multi-point floating support mechanism (3) consists of multiple elastic floating positioning pins, which are secured by fastening blocks on the side. It can achieve conformal support for uncertain curved surfaces. 15 pins are set at the corresponding support plate positions to directly support the support plate. 6 single-point floating support mechanisms (5) are set to support the inner ring of the intake casing.

2. The process method for reducing vibration marks during milling of the air intake casing support plate of an aero-engine according to claim 1, characterized in that, Nine zero-point positioners (13) are provided; eight hydraulic pressure plates (2) are provided for pressing and fixing parts.

3. The process method for reducing vibration marks during milling of the intake casing support plate of an aero-engine according to claim 1, characterized in that, The hydraulic power source is connected through the hydraulic power source interface (8) to realize oil supply and return; the input oil pressure is displayed through the input pressure gauge (9); the accumulator (6) contains a nitrogen spring and replenishing oil, which can be replenished when the oil pressure in the fixture is insufficient; the air source is connected through the air source input port (10) to realize pneumatic control auxiliary support; the pressure inside the fixture is adjusted through the pressure reducing valve (12).

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