Machining process method of cantilever thin-wall weak-rigidity part

Abstract

The invention belongs to the technical field of aero-engines, and particularly relates to a processing technique of a cantilever thin-wall weak-rigidity part, which comprises the following steps of: 1, calculating the single-side wall thickness difference between a forge piece I and a pipe, and controlling the flatness of the upper surface and the lower surface of the forge piece I of the welded forge piece I; 2, the upper surface of the first forge piece and the lower surface of the first forge piece are roughly machined with the lower surface of the first forge piece and the upper surface of the first forge piece as positioning datum planes, and the initial sizes of the upper surface of the first forge piece and the lower surface of the first forge piece are determined; thirdly, the surfaces of the two sides of the forge piece are machined till the designed size is met; and 4, finish machining is conducted on the upper surface of the first forge piece and the lower surface of the first forge piece. According to the method, the machining route of the cantilever thin-wall weak-rigidity part is broken through, and a reference method is provided for machining of the cantilever thin-wall weak-rigidity part; and the problem that the surface tilts when the thin-wall position of the cantilever is machined to be close to the final size is solved by adopting a feeding path of circularly reciprocating the forge piece I.

Description

Technical Field

[0001] The invention belongs to the technical field of aeroengines, and in particular relates to a processing method for a cantilever thin-wall weak-rigidity part. Background Art

[0002] Thin-walled parts with a thickness of less than 3 mm in aircraft engines are usually formed by sheet metal. As the performance requirements of the engine are improved, many thin-walled parts need to be formed by forgings instead of sheet metal. Mechanical processing has the problem of plane warping when approaching the final size. For example, parts welded by thin-walled forgings and pipes, due to the weak rigidity of the pipes and the thin wall thickness of the parts, and the relatively large size of the forgings, such parts are important matching parts of the engine, and the size and shape tolerances of the parts are high. The processing technology of thin-walled parts is highly difficult in the field of mechanical processing. The realization of processing cantilevered thin-walled weak rigidity parts has become an urgent need for engine development. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a processing method for cantilever thin-walled weak rigidity parts, which solves the problem of surface warping when the cantilever thin-wall position of the part is processed close to the final size, meets the part size and shape and position tolerance requirements, and realizes the processing of cantilever thin-walled weak rigidity parts.

[0004] The specific technical solutions are as follows:

[0005] A processing method for a cantilever thin-walled weak rigidity part comprises the following steps:

[0006] Step 1: Calculate the difference in single-side wall thickness between forging 1 and the pipe, and control the flatness of the upper surface and the lower surface of forging 1 after welding, which will serve as the rough machining positioning reference surface;

[0007] Step 2: With the lower surface of the forging and the upper surface of the forging in step 1 as the positioning reference surfaces, perform rough machining on the upper surface of the forging and the lower surface of the forging, and determine the initial dimensions of the upper surface of the forging and the lower surface of the forging, which will serve as the reference dimensions for fine machining and the two side surfaces of the forging;

[0008] Step 3: Using the upper surface of forging 1 and the upper surface of forging 2 with the initial size as the positioning reference surface, process the two side surfaces of the forging until they meet the design size;

[0009] Step 4: With the upper surface of the forging and the lower surface of the forging of the initial size determined as the positioning reference surface, the upper surface of the forging and the lower surface of the forging are finely processed.

[0010] Furthermore, in step one, the single-side wall thickness difference between forging one and the pipe is calculated based on the thickness of forging one and the pipe; the parts are subjected to heat setting and cold forming processes to control the flatness of the upper surface of forging one and the lower surface of forging one after welding, which are used as rough machining positioning reference surfaces, and the flatness is less than the single-side wall thickness difference.

[0011] Furthermore, before rough machining, the upper surface of the forging and the lower surface of the forging are used as positioning reference surfaces, and the circumferential and radial total runout of the upper surface of the forging and the lower surface of the forging are measured to ensure that the flatness of the upper surface of the forging and the lower surface of the forging after welding can satisfy that the wall thickness of the forging is within the machining allowance range; the upper surface of the forging and the lower surface of the forging are rough machined to determine the initial dimensions of the upper surface of the forging and the lower surface of the forging, which are used as the reference dimensions for fine machining and the two side surfaces of the forging.

[0012] Furthermore, in step four, when finishing the upper surface of the forging, the lower surface of the forging with the initial size is used as the positioning reference surface, and for the part farthest from the rotation center of the part, the upper surface of the forging is processed by the tool path from the outer circle to the inner circle, and then the upper surface of the forging is processed by the tool path from the inner circle to the outer circle; when finishing the lower surface of the forging, the upper surface of the forging with the initial size is used as the positioning reference surface, and for the part farthest from the rotation center of the part, the lower surface of the forging is processed by the tool path from the outer circle to the inner circle, and then the lower surface of the forging is processed by the tool path from the inner circle to the outer circle; the forging is processed repeatedly for multiple cycles until the design size is met.

[0013] The beneficial effects of the present invention are:

[0014] The processing method of the present invention opens up a processing route for cantilever thin-walled weak rigid parts and can be widely used in the field of aviation engines; the present invention adapts to the advanced performance improvement of new structure engines and provides a reference method for the processing of cantilever thin-walled weak rigid parts; in view of the problem that the axial reference is difficult to determine after the welded part is deformed in the invention, the positioning surface reference is converted by calculating the part size, the position with large weak rigid deformation is taken as the positioning reference surface, and the tool path of cyclically reciprocatingly processing the upper surface of the forging and the lower surface of the forging is adopted to solve the problem of surface warping when the cantilever thin-wall position is processed close to the final size, and meet the size and shape tolerance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic axial cross-sectional view of a cantilever thin-walled weak rigidity part in the present invention;

[0016] Figure 2 This is a dimensional diagram of the cantilever thin-walled weak rigidity part in the present invention;

[0017] Figure 3 It is a schematic diagram of the tool path of the cantilever thin-walled weak rigid part in the present invention;

[0018] Among them, 1. Forging 1; 2. Forging 2; 3. Pipe; 4. Upper surface of forging 1; 5. Lower surface of forging; 6. Upper surface of forging 2; 7. Pipe wall; 8. Side surfaces of forging 2. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] like Figure 1-Figure 3 As shown, the cantilever thin-walled weak rigidity parts of this embodiment include forging 1, forging 2 and pipe 3; forging 1 and forging 2 are connected by welding at both ends of pipe 3; forging 1, forging 2 and pipe 3 are all thin-walled annular parts; forging 1 and forging 2 need to be machined; forging 1, forging 2 and pipe 3 are 46 mm in total; the inner diameter and outer diameter of forging 1 outside the weld differ by 30 mm, the wall thickness of pipe 3 is 0.8 mm, and the thickness of forging 1 after machining is 1.5 mm. This is an important matching part in the engine, which affects the axial height of the entire engine, and the size and shape tolerance requirements are very strict. Due to the weak rigidity of the tube 3, after welding, forging 1 and forging 2 are not combined into a rigid whole. During the machining process, they must be clamped individually and the size between forging 1 and forging 2 must be accurately positioned in the axial direction. After welding, forging 1, forging 2 and tube 3 present an uneven "wave" shape, that is, the flatness value exceeds the wall thickness difference s between the upper surface 4 of forging 1, the lower surface 5 of forging and the tube 3. According to the principle of coincidence of process datum and design datum, if the design datum is used for processing, there will be a risk of damage to the 0.8 mm tube wall 7 of the tube 3 during the processing.

[0021] In order to meet the requirements of part size and geometric tolerance and the problem that the tube wall 7 of the tube 3 is easily damaged during processing, this embodiment provides a processing method for the above-mentioned cantilever thin-walled weak rigidity part, and the specific steps are as follows:

[0022] Step 1: Calculate the single-side wall thickness difference between the forging 1 and the pipe 3, and control the flatness of the forging 1 upper surface 4 and the forging 1 lower surface 5 of the forging 1 after welding, as the rough machining positioning reference surface;

[0023] like Figure 2 As shown, according to the wall thickness of forging 1 and pipe 3, the single-side wall thickness difference between forging 1 and pipe 3 is calculated as s = (1.5-0.8) / 2 = 0.35 mm. Figure 1When the upper surface 4 and the lower surface 5 of the forging 1 are welded, the wall 7 of the pipe 3 is damaged. The part is clamped by a common fixture for hot setting and cold setting processes. The flatness of the upper surface 4 and the lower surface 5 of the forging 1 after welding is controlled to be 0.3 mm, which is used as a rough machining positioning reference surface; the flatness is less than the single-side wall thickness difference s to avoid damage to the pipe 3.

[0024] Step 2: With the forging lower surface 5 and the forging upper surface 4 in step 1 as the positioning reference surfaces, the forging upper surface 4 and the forging lower surface 5 are rough-machined by a CNC lathe to determine the initial dimensions of the forging upper surface 4 and the forging lower surface 5, which are used as the reference dimensions for fine machining and the forging two side surfaces 8;

[0025] 1) Before machining, take the upper surface 4 of forging 1 and the lower surface 5 of forging 1 as the positioning reference surface, use the dial indicator to measure the circumferential and radial total runout of the upper surface 4 of forging 1 and the lower surface 5 of forging 1, strictly control the state of the upper surface 4 of forging 1 and the lower surface 5 of forging 1, and ensure that the flatness value of the upper surface 4 of forging 1 and the lower surface 5 of forging 1 can meet the wall thickness of forging 1.5 mm within the machining allowance range;

[0026] 2) Under the premise of not "damaging" the tube wall 7, a dial indicator is used to check the highest point of the tube wall of the tube 3 during the rough machining process, that is, when the wall thickness difference s value is (0-0.05) mm, the initial dimensions of the upper surface 4 of the forging and the lower surface 5 of the forging are determined as the reference dimensions for fine machining and the two side surfaces 8 of the forging.

[0027] Step 3: Using the upper surface 4 of the first forging and the upper surface 6 of the second forging with the initial size as the positioning reference surface, the two side surfaces 8 of the forging are processed until the design size is met;

[0028] Step 4: With the upper surface 4 and the lower surface 5 of the forging determined to have initial dimensions as the positioning reference surfaces, the upper surface 4 and the lower surface 5 of the forging (i.e. the cantilever thin-walled part) are finely machined;

[0029] 1) When finishing the forging upper surface 4, the lower surface 5 of the forging with the initial size is used as the positioning reference surface, and the lower surface 5 of the forging is tracked synchronously, that is, the positioning reference surface moves with the processing part to prevent the upper surface 4 of the forging from tilting and deforming during the processing of the forging upper surface 4; for the part farthest from the center of rotation of the part, that is, the cantilever thin-walled part, the part is processed from the outer circle with the weakest rigidity to the inner circle, that is, the tool path from the outside of the forging 1 to the inside, see Figure 3 Then the forging is processed by the tool path from the inner circle to the outer circle, i.e., the tool path from the inside to the outside, see Figure 3 The tool path T2 in the forging is used to control the flatness of the upper surface 4 of the forging by reverse tool movement;

[0030] Similarly, when finishing the lower surface 5 of the forging, the upper surface 4 of the forging with the initial size is used as the positioning reference surface, and the upper surface 4 of the forging is tracked synchronously to prevent the lower surface 5 of the forging from warping and deformation during the processing; for the part farthest from the center of rotation of the part, that is, the cantilever thin-walled part, the part is processed from the outer circle with the weakest rigidity to the inner circle, that is, the tool path from the outside of the forging to the inside, see Figure 3 Then, the lower surface 5 of the forging is processed by the tool path from the inner circle to the outer circle, that is, the tool path from the inside to the outside, see Figure 3 Tool path T4 in the figure controls the flatness of the lower surface 5 of the forging by reverse tool movement;

[0031] 2) According to the processing method of 1) above, the wall thickness of the forging 1 is Mm.

Claims

1. A processing method for cantilever thin-walled weak rigidity parts, characterized in that: The steps include: Step 1: Calculate the difference in single-side wall thickness between forging 1 and the pipe, and control the flatness of the upper surface and the lower surface of forging 1 after welding, which will serve as the rough machining positioning reference surface; Step 2: With the lower surface of the forging and the upper surface of the forging in step 1 as the positioning reference surfaces, perform rough machining on the upper surface of the forging and the lower surface of the forging, and determine the initial dimensions of the upper surface of the forging and the lower surface of the forging, which will serve as the reference dimensions for fine machining and the two side surfaces of the forging; Step 3: Using the upper surface of forging 1 and the upper surface of forging 2 with the initial size as the positioning reference surface, process the two side surfaces of the forging until they meet the design size; Step 4: With the upper surface of the forging and the lower surface of the forging of the initial size determined as the positioning reference surface, the upper surface of the forging and the lower surface of the forging are finely processed.

2. The processing technology of cantilever thin-walled weak rigid parts according to claim 1 is characterized in that: In step one, the single-side wall thickness difference between forging one and the pipe is calculated based on the thickness of forging one and the pipe; the parts are subjected to heat setting and cold forming processes to control the flatness of the upper surface of forging one and the lower surface of forging one after welding, which are used as rough machining positioning reference surfaces, and the flatness is less than the single-side wall thickness difference.

3. The processing technology of cantilever thin-walled weak rigid parts according to claim 1 is characterized in that: Before rough machining, take the upper surface and the lower surface of forging as positioning reference planes, measure the circumferential and radial total runout of the upper surface and the lower surface of forging, ensure that the flatness of the upper surface and the lower surface of forging after welding can satisfy the wall thickness of forging within the machining allowance range; perform rough machining on the upper surface and the lower surface of forging, determine the initial size of the upper surface and the lower surface of forging, as the reference size for fine machining and the two side surfaces of forging.

4. The processing technology of cantilever thin-walled weak rigid parts according to claim 1 is characterized in that: In step 4, when finishing the upper surface of the forging, the lower surface of the forging with the initial size is used as the positioning reference surface, and the upper surface of the forging is processed by the tool path from the outer circle to the inner circle for the part farthest from the rotation center of the part, and then the upper surface of the forging is processed by the tool path from the inner circle to the outer circle; when finishing the lower surface of the forging, the upper surface of the forging with the initial size is used as the positioning reference surface, and the lower surface of the forging is processed by the tool path from the outer circle to the inner circle for the part farthest from the rotation center of the part, and then the lower surface of the forging is processed by the tool path from the inner circle to the outer circle; the forging is processed repeatedly for multiple cycles until the design size is met.

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