Process method for reducing milling vibration marks of aero-engine air inlet casing support plate

Abstract

The invention belongs to the field of production of parts of aero-engines, and particularly relates to a process method for reducing milling vibration marks of a support plate of an air inlet casing of an aero-engine. The specific method comprises the steps that a clamp is designed, the clamp is installed on a machine tool, a part is placed and locked on the clamp, the final surface of the part serves as the standard, the allowance of 4 mm is reserved for milling, the remaining machining amount of all the supporting plates is unified, the front edges of the supporting plates of the part are milled in a layered machining mode at each cutting depth of 1 mm, and after final machining is completed, the front edges of the supporting plates of the part are machined. And the cutter is machined again according to the final size of the part, and the cutter relieving amount is removed. A traditional part clamping and positioning method is changed, the problem that the machining rigidity of the part is poor according to a common clamping mode is solved, machining stress is reduced, part machining cutter relieving is completely eliminated, the supporting plate machining quality is improved, meanwhile, more than 80% of machining vibration marks are eliminated, and the rework rate is reduced.

Description

Technical Field

[0001] The invention belongs to the field of aircraft engine parts production, and in particular relates to a process for reducing vibration marks in milling of an aircraft engine air intake casing support plate. Background Art

[0002] The present invention relates to the problem of improving the processing quality of a type of aircraft engine parts. The air intake casing parts are the main parts of the aircraft engine fan part, which are used to adjust the airflow entering the aircraft engine. The functional characteristics of the parts determine that the local rigidity of the parts is poor. When milling the front edge of the support plate, there is a serious machining cutter let-down situation, and the surface quality of the parts is poor, and there are a large number of machining vibration marks, which affects the appearance quality and service life of the parts. At the same time, due to the structural problems of the parts, the support plate is in a suspended position, and the support plate profiles vary greatly, resulting in the inability to stably clamp and fix the parts.

[0003] Prior to the present invention, attempts have been made to use rigid auxiliary support positioning fixtures and other methods to enhance the rigidity of part clamping, but the problem has not been solved because the position and size differences of the part support plates are large and cannot meet the requirements. Summary of the invention

[0004] In view of the problems in the prior art, the present invention provides a process method for reducing chatter marks in milling of an aero-engine air intake casing support plate.

[0005] The technical solution of the present invention is: A process for reducing chatter marks in milling of an aero-engine air intake casing support plate comprises the following steps: Step (1) Design a fixture, install the fixture on the machine tool, and place and lock the parts on the fixture; Step (ii) Taking the final surface of the part as the reference, reserve 4mm margin for milling, unify the remaining processing amount of all support plates, adopt layered processing method, and mill the front edge of the support plate of the part with a cutting depth of 1mm per cut; Step (iii) After the final processing is completed, the part is processed again according to the final size to remove the cutting allowance; The fixture body adopts an annular part fixture structure design, including a base, a positioning mechanism, and a clamping mechanism, including a fixture base, a pressure alarm assembly, an accumulator, a main clamping pressure gauge, a hydraulic source interface, an input pressure gauge, an air source input port, a quick-install 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 lifting function and is quickly connected to the machine tool through a zero-point locator; the pressure alarm assembly is installed on the fixture base through screws, multiple hydraulic pressure plates are arranged and evenly distributed on the outside of the part installation edge, multiple multi-point floating support mechanisms are arranged corresponding to the support plate positions, the single-point floating support mechanism and the accumulator are distributed on the inner ring of the part, and the accumulator is arranged 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, 3 quick-install lifting interfaces are arranged and evenly distributed on the outermost side of the fixture base, and the positioning ring is coaxially distributed with the fixture base and fixed on the fixture base.

[0006] Furthermore, the above-mentioned process method for reducing vibration marks in milling processing of aircraft engine intake casing support plates has a preferred solution that a multi-point floating support mechanism is composed of a plurality of elastic floating positioning pins, and side locking is achieved by side fastening blocks, which can achieve conformal support for uncertain curved surfaces, and 15 corresponding support plate positions are arranged for directly supporting the support plates; 6 single-point floating support mechanisms are arranged for supporting the inner ring of the intake casing.

[0007] Furthermore, the above-mentioned process method for reducing chatter marks in the milling of an aircraft engine air intake casing support plate has a preferred embodiment in which 9 zero point positioners are provided and 8 hydraulic pressure plates are provided to clamp and fix the parts.

[0008] Furthermore, the above-mentioned process method for reducing vibration marks in the milling of aircraft engine intake casing support plates has a preferred solution that: the hydraulic source is connected through a hydraulic source interface to realize oil supply and oil return; the input oil pressure is displayed by an input pressure gauge; the accumulator contains a nitrogen spring and supplementary oil, and can be supplemented when the oil pressure in the fixture is insufficient; the air source is connected through the air source input port to realize pneumatically controlled auxiliary support; and the internal pressure of the fixture is adjusted by a pressure reducing valve.

[0009] Advantages and beneficial effects of the present invention: 1. The present invention adjusts the machining allowance of each program run during milling according to the welding deformation of the support plate, so as to reduce the amount of machining each time, thereby reducing the cutting force and the stress during the support plate machining.

[0010] 2. The present invention changes the traditional parts clamping and positioning method, solves the problem of poor rigidity of parts processed by ordinary clamping methods, reduces processing stress, completely eliminates tool deflection during parts processing, improves the support plate processing quality, and eliminates more than 80% of processing vibration marks, reducing the rework rate. A single engine can save about 3,000 yuan in processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the processing position of the intake casing support plate; Figure 2This is a schematic diagram of the tool path for the part milling program; Figure 3 is a schematic diagram of the fixture model; Figure 4 is a schematic diagram of the fixture structure; Figure 5 It is a schematic diagram of a multi-point floating support mechanism; In the figure, 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 lifting interface; 12-pressure reducing valve; 13-zero point positioner; 14-positioning ring. DETAILED DESCRIPTION

[0012] The specific implementation modes of the present invention are further described in detail below in conjunction with the drawings and examples of the specification. The following examples are used to illustrate the present invention but cannot be used to limit the scope of the present invention. Example 1

[0013] like Figure 3 , 4 As shown, the fixture body used in this embodiment adopts an annular part fixture structure design, including a base, a positioning mechanism, and a clamping mechanism, including a fixture base 1, a pressure alarm assembly 4, an accumulator 6, a main clamping pressure gauge 7, a hydraulic source interface 8, an input pressure gauge 9, an air source input port 10, a quick-install 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 is quickly connected to the machine tool through 9 zero-point positioners 13; the pressure alarm assembly 4 is installed on the fixture base 1 by screws, 8 hydraulic pressure plates 2 are set and evenly distributed outside the part installation edge, and 15 multi-point floating support mechanisms 3 are set corresponding to the support plate positions, such as Figure 5 As shown, the multi-point floating support mechanism is composed of a plurality of elastic floating positioning pins, and the side locking is realized by the fastening block on the side. The single-point floating support mechanism 5 and the accumulator 6 are distributed on the inner ring of the part, and the accumulator 6 is arranged between the hydraulic pressure plate 2 and the multi-point floating support mechanism 3. Six single-point floating support mechanisms 5 are arranged; the main clamping pressure gauge 7, the hydraulic source interface 8, the input pressure gauge 9, the air source input port 10 and the pressure reducing valve 12 are distributed in parallel and installed at the lower end of the fixture base 1, and three quick-install lifting interfaces 11 are arranged 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.

[0014] In this embodiment, the milling position of the aircraft engine air intake casing support plate is the front edge of the support plate. Figure 1As shown, because the support plate is welded on the outer ring of the parts, the deformation of different parts is inconsistent, and the maximum margin can reach 5mm. The traditional solution is to directly process it in place according to the final size, and the processing amount is too large. Therefore, the processing solution of this position is adjusted to layered processing in the present invention. The specific processing method is: Step 1: Install the above fixture on the machine tool through the zero point locator 13; Step 2: Place the part on the fixture so that the part reference plane contacts the upper surface of the fixture positioning ring 14; Step 3: Check the gap between the part reference surface and the upper surface of the fixture positioning ring 14 in the free state. If there is a gap, use a feeler gauge to level it. Step 4: Align the cylindrical surface of the part so that the part and the fixture are coaxial, 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 it to support the inner ring of 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: Call up the milling program, reserve 4mm margin for milling, and unify the remaining processing volume of all support plates; Step 8: Call up the milling program and leave a 3mm margin to complete the milling of the front edge of the support plate. Figure 2 As shown, it is a schematic diagram of the tool path; Retrieve the milling program and leave a 2mm margin to complete the milling of the front edge of the support plate; Retrieve the milling program and leave a 1mm margin to complete the milling of the front edge of the support plate; Retrieve the milling program and complete the milling of the front edge of the support plate according to the final size; Step 9: After the final processing is completed, run the program again according to the final size of the part to remove the tool allowance.

Claims

1. A process for reducing chatter marks in milling of an aero-engine air intake casing support plate, characterized in that: The following steps are involved: Step (1) Design a fixture, install the fixture on the machine tool, and place and lock the parts on the fixture; Step (ii) Taking the final surface of the part as the reference, reserve 4mm margin for milling, unify the remaining processing amount of all support plates, adopt layered processing method, and mill the front edge of the support plate of the part with a cutting depth of 1mm per cut; Step (iii) After the final processing is completed, the part is processed again according to the final size to remove the cutting allowance; The clamp body adopts an annular part clamp structure design, comprising a base, a positioning mechanism, and a clamping mechanism, wherein the clamp body comprises a clamp base (1), a pressure alarm assembly (4), an accumulator (6), a main clamping pressure gauge (7), a hydraulic source interface (8), an input pressure gauge (9), an air source input port (10), a quick-install lifting interface (11), a pressure reducing valve (12), and a zero point positioner (13); the positioning mechanism comprises a multi-point floating support mechanism (3), a single-point floating support mechanism (5), and a positioning ring (14); and the clamping mechanism is a hydraulic pressure plate (2); The base has a lifting function and is quickly connected to the machine tool through a zero point positioner (13); the pressure alarm assembly (4) is installed on the fixture base (1) through screws; a plurality of hydraulic pressure plates (2) are arranged and evenly distributed on the outside of the part installation edge; a plurality of multi-point floating support mechanisms (3) are arranged corresponding to the support plate positions; the single-point floating support mechanism (5) and the accumulator (6) are distributed on the inner ring of the part, and the accumulator (6) is arranged between the hydraulic pressure plate (2) and the multi-point floating support mechanism (3); the main clamping pressure gauge (7), the hydraulic source interface (8), the input pressure gauge (9), the air source input port (10) and the pressure reducing valve (12) are arranged in parallel and installed at the lower end of the fixture base (1); three quick-install lifting interfaces (11) are arranged and evenly distributed on the outermost side of the fixture base (1); and the positioning ring (14) is coaxially distributed with the fixture base (1) and fixed on the fixture base (1).

2. A process for reducing chatter marks in milling of an aircraft engine air intake casing support plate according to claim 1, characterized in that: The multi-point floating support mechanism (3) is composed of a plurality of elastic floating positioning pins, which are locked by side fastening blocks, and can realize conformal support for uncertain curved surfaces. 15 pins are arranged at corresponding support plate positions for directly supporting the support plate. Six single-point floating support mechanisms (5) are arranged for supporting the inner ring of the air intake casing.

3. A process for reducing vibration marks in milling of an aircraft engine air intake casing support plate, characterized in that: Nine zero point positioners (13) are provided; and eight hydraulic pressure plates (2) are provided for clamping and fixing parts.

4. The process for reducing chatter marks in milling of an aircraft engine air intake casing support plate according to claim 1, characterized in that: The hydraulic source is connected via the hydraulic source interface (8) to realize oil supply and oil return; the input oil pressure is displayed via the input pressure gauge (9); the accumulator (6) contains a nitrogen spring and supplementary oil, which can be supplemented when the oil pressure in the fixture is insufficient; the air source is connected via the air source input port (10) to realize pneumatic control auxiliary support; the internal pressure of the fixture is adjusted via the pressure reducing valve (12).

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