Numerical control machining method for side groove of aviation structural member edge strip

Abstract

The application discloses an aviation structural member edge strip side groove numerical control machining method and belongs to the technical field of numerical control machining, and is characterized by comprising the following steps: S1, determining a cutter and determining a machining swing angle delta; S2, when machining a first surface, coarsely milling an edge strip side groove; S3, when machining the first surface, finely milling a web curved surface; S4, when machining a second surface, supplementally machining the web curved surface; and S5, when machining the second surface, finely milling an edge strip profile. The edge strip side groove is machined in two surfaces through a large-swing-angle forming end mill, and the method is simple and efficient, reduces the subsequent bench work polishing amount, guarantees the machining quality of the edge strip side groove, improves machining efficiency and shortens the machining cycle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of numerical control machining, and in particular to a numerical control machining method for a side groove of a rim strip of an aviation structural part. BACKGROUND

[0002] With the development of aviation technology, aviation structural parts will have side groove structures designed on their rim strips due to assembly needs, and the rim strip side grooves are becoming more and more common. The side groove is composed of a web curved surface, a intersecting fillet, and a rim strip profile composed of two corner connecting planes. This structure is often located on the side rim strip of the part profile. For the mechanical machining field, this structure is difficult to machine. There are two common methods in the prior art: the first method is to use a special disc cutter to directly cut into the side groove to form the opening size of the side groove according to the size of the side groove. Since the precision of the disc cutter is limited, the processing allowance needs to be measured during the disc cutter machining to ensure that the size of the side groove is qualified. Subsequently, other tools need to be used to further machine the intersecting fillet, web curved surface, and corner area of the rim strip profile. However, due to the low rigidity of the side groove itself, there is a great risk of the disc cutter and broach during the machining process. The above method may cause a large amount of unprocessed allowance to remain in the side groove structure, and also increases the workload of subsequent bench work polishing, greatly increasing the part polishing time.

[0003] Chinese patent document with publication number CN110560761A and publication date of December 13, 2019 discloses a numerical control machining method for an aluminum alloy rim strip side groove, which is characterized by the following steps:

[0004] a. Design the size of the process boss connected with the part side groove and the relief groove on the process boss, and machine other features of the part except the relief groove and the side groove, including the process boss and the connecting piece between the process boss and the rim strip;

[0005] b. Select a machining tool according to the minimum size of the groove opening contour of the side groove, machine the relief groove on the process boss, and the relief groove penetrates the process boss along the normal direction of the part rim strip profile surface where the side groove is located, and the projection on the plane perpendicular to the normal direction envelops the projection of the part side groove on the plane;

[0006] c. Select the machining tool in step b, and finish milling the side groove of the part;

[0007] d. Break the process boss and the connecting piece.

[0008] The patent document discloses a CNC machining method for aluminum alloy flange side grooves. This method divides the flange side groove machining process into other feature machining, avoidance groove machining, and side groove machining. A large-diameter milling cutter is used to complete the side groove and other features related to the avoidance groove, while a small-diameter milling cutter is used to complete the avoidance groove and side groove machining, thus ensuring the machining quality of the flange side groove. However, this division into other feature machining, avoidance groove machining, and side groove machining complicates the entire machining process, affecting machining efficiency and extending the machining cycle. Summary of the Invention

[0009] In order to overcome the defects of the above-mentioned prior art, the present invention provides a CNC machining method for the side grooves of the edge strips of aviation structural parts. The present invention processes the side grooves of the edge strips on two sides by using a forming end mill with a large swing angle. The method is simple and efficient. While reducing the amount of subsequent benchwork and grinding, it ensures the machining quality of the side grooves of the edge strips, improves machining efficiency, and shortens the machining cycle.

[0010] The present invention is achieved through the following technical solutions:

[0011] A numerical control machining method for a side groove of an aviation structural part flange, characterized by comprising the following steps:

[0012] S1. Determine the tool and the machining swing angle δ;

[0013] S2. When machining the first side, rough mill the side groove of the flange strip;

[0014] S3. When machining the first side, finish mill the web surface;

[0015] S4. When machining the second side, the web surface is additionally machined;

[0016] S5. When machining the second side, finish milling the edge strip surface.

[0017] In the step S1, determining the tool means selecting a forming end mill according to the curvature of the surface of the intersecting fillet.

[0018] In step S1, determining the machining swing angle δ means measuring the opening size of the side groove of the edge strip of the part to be machined. and the thickness of the flange side groove , calculate the angle α formed by the tool and the opening of the groove on the side of the edge strip, and the machining swing angle δ>α+β, where β is the tool taper.

[0019] The angle α formed by the tool and the opening of the side groove of the edge strip is calculated by formula 1;

[0020] Formula 1

[0021] in, is the thickness of the side groove of the flange, The opening size of the side groove of the bead.

[0022] The machining swing angle δ is determined by formula 2;

[0023] δ = α + β + Δ formula 2

[0024] Wherein, Δ ranges from 10-25°.

[0025] In the step S2, before rough milling the side groove of the bead, a boss lap is additionally arranged at a position outside the groove opening of the bead.

[0026] In the step S2, rough milling the side groove of the bead refers to milling the side groove of the bead on the bead, and reserving a finishing allowance for the web curved surface, the intersecting fillet and the bead profile.

[0027] In the step S4, the supplementary machining web curved surface tool path partially overlaps the finishing web curved surface tool path.

[0028] The beneficial effects of the present application mainly include the following aspects:

[0029] 1. Compared with the prior art, the present application processes the side groove of the bead in two surfaces through a large swing angle of a shaped end mill, which is simple and efficient, reduces the subsequent bench work polishing amount, ensures the processing quality of the side groove of the bead, improves the processing efficiency, and shortens the processing cycle.

[0030] 2. In the step S2 of the present application, a boss lap is additionally arranged at a position outside the groove opening of the bead before rough milling the side groove of the bead, which can increase the rigidity of the side groove of the bead and prevent the occurrence of a snap cutter or a broach in subsequent formal processing, thereby being beneficial to ensuring the processing stability and the processing quality.

[0031] 3. In the step S4 of the present application, the supplementary machining web curved surface tool path partially overlaps the finishing web curved surface tool path, which can ensure that the web curved surface is processed by two surface swing angles, and the web curved surface will not leave a tool joint mark.

[0032] 4. The whole processing method of the present application is simple and fast, which can effectively reduce the processing cycle of the aviation structure, and has good applicability. BRIEF DESCRIPTION OF DRAWINGS

[0033] The present application will be further specifically described below in combination with the drawings of the specification and the specific embodiments:

[0034] Figure 1 It is a structure schematic view of the side groove of the bead of the present application;

[0035] Figure 2 It is a structure schematic view of rough milling the side groove of the bead in the first surface processing of the present application;

[0036] Figure 3The structural schematic view of the first surface machining of the invention;

[0037] Figure 4 The cutter swing angle schematic view of the invention;

[0038] Figure 5 The structural schematic view of the second surface machining of the invention;

[0039] Figure 6 The structural schematic view of the second surface machining of the invention;

[0040] The mark in the figure: 1, web curved surface, 2, intersecting fillet, 3, edge strip surface, 4, forming end mill, 5, boss lap, 6, rough milling tool path, 7, fine milling web curved surface tool path, 8, supplementary processing web curved surface tool path, 9, fine milling edge strip surface tool path, , edge strip side groove opening size, , edge strip side groove thickness, α, the included angle formed by the cutter and the edge strip side groove opening, β, the taper of the cutter. DETAILED DESCRIPTION

[0041] Example 1

[0042] Referring to Figure 1 A numerical control machining method of the edge strip side groove of an aviation structural member, comprising the following steps:

[0043] S1, determining the cutter and determining the machining swing angle δ;

[0044] S2, rough milling the edge strip side groove in the first surface machining;

[0045] S3, fine milling the web curved surface 1 in the first surface machining;

[0046] S4, supplementary processing the web curved surface 1 in the second surface machining;

[0047] S5, fine milling the edge strip surface 3 in the second surface machining.

[0048] Compared with the prior art, the edge strip side groove is machined in two surfaces by the large swing angle of the forming end mill 4, which is simple and efficient, reduces the subsequent benchwork polishing amount, guarantees the machining quality of the edge strip side groove, improves the machining efficiency, and shortens the machining cycle.

[0049] Example 2

[0050] Referring to Figure 1 A numerical control machining method of the edge strip side groove of an aviation structural member, comprising the following steps:

[0051] S1, determining the cutter and determining the machining swing angle δ;

[0052] S2, rough milling the string side groove in the first surface processing;

[0053] S3, fine milling the web curved surface 1 in the first surface processing;

[0054] S4, supplementary processing the web curved surface 1 in the second surface processing;

[0055] S5, fine milling the string profile 3 in the second surface processing.

[0056] In the step S1, the determination of the tool refers to selecting a profile end mill 4 according to the curved surface curvature of the intersecting round corner 2.

[0057] In the step S1, the determination of the processing swing angle δ refers to measuring the opening size of the string side groove of the part to be processed and the thickness of the string side groove , calculating the included angle α formed by the tool and the opening of the string side groove, and the processing swing angle δ > α + β, where β is the taper of the tool.

[0058] Example 3

[0059] Referring to Figure 1 , a numerical control processing method for a string side groove of an aviation structural part, comprising the following steps:

[0060] S1, determining the tool and determining the processing swing angle δ;

[0061] S2, rough milling the string side groove in the first surface processing;

[0062] S3, fine milling the web curved surface 1 in the first surface processing;

[0063] S4, supplementary processing the web curved surface 1 in the second surface processing;

[0064] S5, fine milling the string profile 3 in the second surface processing.

[0065] In the step S1, the determination of the tool refers to selecting a profile end mill 4 according to the curved surface curvature of the intersecting round corner 2.

[0066] In the step S1, the determination of the processing swing angle δ refers to measuring the opening size of the string side groove of the part to be processed and the thickness of the string side groove , calculating the included angle α formed by the tool and the opening of the string side groove, and the processing swing angle δ > α + β, where β is the taper of the tool.

[0067] The included angle α formed by the tool and the opening of the string side groove is calculated by formula 1;

[0068] Formula 1

[0069] wherein, is the thickness of the string side groove, is the opening size of the string side groove.

[0070] Example 4

[0071] Referring to Figure 1 A numerical control machining method of a string side groove of an aeronautical structure, comprising the following steps:

[0072] S1, determining a tool and determining a machining swing angle δ;

[0073] S2, when machining the first surface, roughly milling the string side groove;

[0074] S3, when machining the first surface, finely milling the web curved surface 1;

[0075] S4, when machining the second surface, supplementally machining the web curved surface 1;

[0076] S5, when machining the second surface, finely milling the string profile 3.

[0077] In the step S1, the tool is determined according to the curved surface curvature of the intersecting fillet 2.

[0078] In the step S1, the machining swing angle δ is determined by measuring the opening size of the string side groove of the part to be machined and the thickness of the string side groove , calculating the included angle α formed by the tool and the opening of the string side groove, and the machining swing angle δ > α + β, wherein β is the taper of the tool.

[0079] The included angle α formed by the tool and the opening of the string side groove is calculated by formula 1;

[0080] Formula 1

[0081] wherein, is the thickness of the string side groove, is the opening size of the string side groove.

[0082] The machining swing angle δ is specifically determined by formula 2;

[0083] δ = α + β + Δ Formula 2

[0084] wherein, Δ ranges from 10-25°.

[0085] Example 5

[0086] Referring to Figure 1 A numerical control machining method of a string side groove of an aeronautical structure, comprising the following steps:

[0087] S1, determining a tool and determining a machining swing angle δ;

[0088] S2, rough milling the edge strip side groove during first surface machining;

[0089] S3, finish milling the web curved surface 1 during first surface machining;

[0090] S4, supplementary machining the web curved surface 1 during second surface machining;

[0091] S5, finish milling the edge strip profile 3 during second surface machining.

[0092] In the step S1, determining the tool refers to selecting a profile end mill 4 according to the curved surface curvature of the intersecting fillet 2.

[0093] In the step S1, determining the machining swing angle δ refers to measuring the opening size of the edge strip side groove of the part to be machined and the thickness of the edge strip side groove , calculating the included angle α formed by the tool and the opening of the edge strip side groove, and the machining swing angle δ > α + β, where β is the tool taper.

[0094] The included angle α formed by the tool and the opening of the edge strip side groove is calculated by formula 1;

[0095] Formula 1

[0096] wherein, is the thickness of the edge strip side groove, is the opening size of the edge strip side groove.

[0097] The machining swing angle δ is specifically calculated and determined by formula 2;

[0098] δ = α + β + Δ Formula 2

[0099] wherein, Δ ranges from 10-25°.

[0100] In the step S2, before rough milling the edge strip side groove, a boss lap 5 is additionally provided at a position outside the edge strip opening.

[0101] In the step S2, rough milling the edge strip side groove refers to milling the edge strip side groove on the edge strip, and reserving a finish machining allowance for the web curved surface 1, the intersecting fillet 2 and the edge strip profile 3.

[0102] In step S2, before rough milling the edge strip side groove, a boss lap 5 is additionally provided at a position outside the edge strip opening, which can increase the rigidity of the edge strip side groove and prevent the occurrence of a spring tool or a broach during subsequent formal machining, thereby facilitating the protection of machining stability and machining quality.

[0103] Example 6

[0104] Referring to Figure 1 , a numerical control machining method for an edge strip side groove of an aviation structural part, comprising the following steps:

[0105] S1, determining the tool and determining the machining swing angle δ;

[0106] S2, rough milling the rim strip side groove when machining the first surface;

[0107] S3, fine milling the web curved surface 1 when machining the first surface;

[0108] S4, supplementary machining the web curved surface 1 when machining the second surface;

[0109] S5, fine milling the rim strip profile 3 when machining the second surface.

[0110] In the step S1, the tool is determined according to the curved surface curvature of the intersecting fillet 2.

[0111] In the step S1, the machining swing angle δ is determined by measuring the opening size of the rim strip side groove of the part to be machined and the thickness of the rim strip side groove , calculating the included angle α formed by the tool and the opening of the rim strip side groove, and the machining swing angle δ > α + β, where β is the taper of the tool.

[0112] The included angle α formed by the tool and the opening of the rim strip side groove is calculated by formula 1;

[0113] Formula 1

[0114] wherein, is the thickness of the rim strip side groove, is the opening size of the rim strip side groove.

[0115] The machining swing angle δ is specifically calculated and determined by formula 2;

[0116] δ = α + β + Δ Formula 2

[0117] wherein, Δ ranges from 10-25°.

[0118] Further preferably, in the step S2, a boss lap 5 is additionally provided at a position outside the rim strip opening before rough milling the rim strip side groove.

[0119] In the step S2, the rough milling of the rim strip side groove refers to milling the rim strip side groove on the rim strip, and reserving a fine machining allowance for the web curved surface 1, the intersecting fillet 2 and the rim strip profile 3.

[0120] In the step S4, the tool path 8 for supplementary machining the web curved surface partially overlaps the tool path 7 for fine milling the web curved surface.

[0121] In step S4, the supplementary machining web curved surface tool path 8 partially overlaps the finish milling web curved surface tool path 7, which can ensure that the web curved surface 1 is machined by two-face swing angle machining, and the web curved surface 1 will not leave tool joint marks.

[0122] The whole machining method is simple and fast, can effectively reduce the machining cycle of the aviation structure, and has good applicability.

[0123] The specific machining process of the present application is described below:

[0124] First, the opening size of the side groove of the bead is 8.5mm, the thickness of the side groove of the bead is 2mm, the included angle α formed by the tool and the opening of the side groove of the bead is 13° calculated according to formula 1, the tool taper β is 10°, and the machining swing angle δ is 45° determined according to formula 2.

[0125] After the machining swing angle is determined, it is applicable in both two-face machining, when the bead with the side groove and the web surface form an opening angle and a closing angle, the tool can be machined from the side with the opening angle. Before machining, a boss lap 5 is added at the position outside the opening of the side groove of the bead, which increases the rigidity of the side groove of the bead, and can prevent the influence of the subsequent formal machining of the spring tool.

[0126] The rough milling of the side groove of the bead mills the side groove of the bead on the bead, and reserves the finish machining allowance on the web curved surface 1, the intersecting fillet 2 and the bead surface 3. The rough milling of the side groove of the bead can offset the rough milling tool path 6 radially according to the thickness of the side groove of the bead, the supplementary machining web curved surface tool path 8 partially overlaps the finish milling web curved surface tool path 7, which can ensure that the web curved surface 1 is machined by two-face swing angle machining, and the web curved surface 1 will not leave tool joint marks, ensuring the machining quality.

Claims

1. A CNC machining method for side grooves of flanges of aviation structural parts, characterized in that: The following steps are involved: S1. Determine the tool and the machining swing angle δ; S2. When machining the first side, rough mill the side groove of the flange strip; S3, when machining the first side, finish milling the web surface (1); S4. When machining the second surface, the web surface (1) is additionally machined. S5. When machining the second surface, finish mill the edge strip profile (3); In step S1, determining the machining swing angle δ means measuring the opening size of the side groove of the edge strip of the part to be machined. and the thickness of the flange side groove , calculate the angle α formed by the tool and the opening of the groove on the side of the edge strip, and the machining swing angle δ>α+β, where β is the tool taper; The angle α formed by the tool and the opening of the side groove of the edge strip is calculated by formula 1; Formula 1 in, is the thickness of the side groove of the flange, It is the opening size of the side groove of the flange.

2. The CNC machining method for the side groove of an aviation structural part flange according to claim 1, characterized in that: In the step S1, determining the tool means selecting a forming end mill (4) according to the curvature of the surface of the intersecting fillet (2).

3. The CNC machining method for the side groove of an aviation structural part flange according to claim 1, characterized in that: The machining swing angle δ is specifically determined by calculation using Formula 2: δ=α+β+∆Equation 2 The range of ∆ is 10-25°.

4. The CNC machining method for side grooves of flanges of aviation structural parts according to claim 1, characterized in that: In the step S2, before rough milling the side groove of the edge strip, a boss overlap (5) is added at a position outside the edge strip groove.

5. The CNC machining method for the side groove of an aviation structural part flange according to claim 2, characterized in that: In step S2, rough milling of the flange side grooves refers to milling the flange side grooves on the flange, and reserving finishing allowances on the web curved surface (1), the intersecting fillet (2) and the flange profile (3).

6. The CNC machining method for side grooves of flanges of aviation structural parts according to claim 1, characterized in that: In the step S4, the supplementary web curved surface tool path (8) partially overlaps with the fine milling web curved surface tool path (7).

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