A boss part, boss part space profile processing method and clamp

Abstract

The application discloses a convex seat part, a convex seat part space surface machining method and a clamp, a mandrel with an inclined upper end surface and a groove is made according to the structural characteristics of the convex seat part, and the convex seat part is pressed by a screw rod and a nut. During machining, a five-axis linkage machining mode is adopted, during modeling, a cylindrical envelope convex seat part space surface to be machined is adopted, and during programming, a tool path is continuous and uninterrupted, and the tool path is fed along a circumferential direction from outside to inside, the machining process only has one feeding, and continuous cutting is followed by tool retraction. The application solves the technical problem that the convex seat part cannot be machined in one time when three-axis numerical control milling is used, makes numerical control tool path continuous and smooth and uninterrupted, reduces the risk of tool jumping, interference and machine collision, explores an effective machining method and clamp, and enables the convex seat part to be produced in high quality, high efficiency and stability.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine manufacturing, specifically a machining method and fixture for the spatial surface of irregularly shaped parts, and more specifically a five-axis linkage machining method and corresponding fixture. Background Technology

[0002] The aircraft engine boss is a type of mounting bracket part in the fan housing. Mounting bracket parts are widely used in aircraft engines for various purposes. This particular boss part has a relatively complex structure. The bottom surface of the part is rectangular, and the angle between the upper profile of the bottom surface and the vertical planes (cylindrical surfaces M and N) is 85°. The upper profile gradually transitions to cylindrical surface N. The structure of the boss part is shown in [the provided text]. Figure 1 and Figure 2 .

[0003] For typical mounting bracket parts, the angle between the profile and the vertical plane is usually 90°, which can be achieved using three-axis CNC milling technology. However... Figure 1 and Figure 2 The angle between the upper surface of the boss part and the vertical surface is 85°, and the outer circle dimension at the upper cylindrical surface M of the part is larger than the outer circle dimension at the cylindrical surface N. Traditional three-axis CNC milling cannot process it in one go, resulting in low processing efficiency, poor consistency and unstable processing quality of the boss part. Summary of the Invention

[0004] The present invention aims to provide a boss part, a method for machining the spatial surface of the boss part, and a fixture, to solve the technical problem that such boss parts cannot be machined in one step when using three-axis CNC milling, so that the CNC toolpath is continuous and smooth without interruption, reducing the risk of tool skipping, interference and collision, and exploring an effective machining method and fixture, so that the boss parts can be produced with high quality, high efficiency and stable performance.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A boss component, comprising,

[0007] The base includes an upper surface, which is curved and has a rectangular outer contour.

[0008] The protrusion is connected to the upper surface and includes coaxial cylindrical surfaces M and N. The outer diameter of cylindrical surface M is larger than the outer diameter of cylindrical surface N. Cylindrical surface N is located between cylindrical surface M and the upper surface and is connected to the upper surface. The angle between cylindrical surface M, cylindrical surface N and the upper surface is not equal to 90 degrees.

[0009] A through hole, which penetrates the base and the protrusion, and is coaxial with cylindrical surfaces M and N.

[0010] A fixture for machining the spatial surface of a boss part, comprising,

[0011] The mandrel is a rotating structure. The upper end face of the mandrel forms a first included angle with the axis of rotation, and the first included angle is equal to the included angle between the upper profile of the boss part and the cylindrical surface M and the cylindrical surface N. A groove is opened on the upper end face of the mandrel. The bottom surface of the groove is parallel to the upper end face of the mandrel. A threaded hole is opened on the bottom surface of the groove. The central axis of the threaded hole coincides with the axis of rotation of the mandrel.

[0012] A screw, which is inserted into the through hole of the boss part and its lower end is connected to the threaded hole on the bottom surface of the mandrel groove;

[0013] A nut, which is connected to the upper end of the screw and presses against the upper end of the cylindrical surface M of the boss part.

[0014] Furthermore, the inner contour shape of the groove is consistent with the outer contour shape of the upper surface.

[0015] Furthermore, the inner contour dimension of the groove is larger than the outer contour dimension of the upper surface, so that when the boss part is placed in the groove and closely adheres to the bottom surface of the groove, there is a gap between the circumferential surface of the base of the boss part and the inner surface of the groove.

[0016] Furthermore, the fixture for machining the spatial surface of the boss part also includes a washer, which is sleeved on the screw and installed between the nut and the end face of the boss part.

[0017] A method for machining the spatial surface of a boss part, employing five-axis linkage machining of the upper surface of the boss part, and including:

[0018] The mounting steps for the boss part are as follows: using the aforementioned machining fixture, insert the base of the boss part into the groove of the mandrel, and connect the screw through the through hole of the boss part to the threaded hole in the groove. Then, use a nut to press the boss part tightly from the upper end of the screw.

[0019] The modeling steps for the boss part are as follows: When modeling, a cylindrical body is used to enclose the base, and the outer contour of the upper surface is expanded from a rectangle to a circle.

[0020] The five-axis linkage programming steps employ a continuous, uninterrupted toolpath approach, advancing the tool once from the outside in along the circumference, and then retracting after continuous cutting.

[0021] Alternatively, in the five-axis linkage programming steps, a ball end mill is used when creating the machining tool.

[0022] Alternatively, in the five-axis linkage programming steps, streamlined driving is used and two flow curves are selected.

[0023] As an alternative, in the five-axis linkage programming steps, the projection method is selected as perpendicular to the driving body.

[0024] As an option, in the five-axis linkage programming steps, the tool axis control mode is selected as interpolation vector.

[0025] Compared with the prior art, the present invention has the following characteristics:

[0026] 1. Based on the structural analysis of the boss part, the final clamping and machining scheme is obtained. Since the surface of the machined part of the boss part has an angular positional relationship with other parts, the angular direction of the boss part must be determined during clamping. There is a three-axis interference area in the machined part of the boss part, so a five-axis linkage machining method is required.

[0027] 2. The machining fixture was designed according to the clamping scheme. The present invention divides the machining fixture of the boss part into two parts: one part is a shaft structure for supporting and angular positioning of the boss part; the other part is a clamping structure for clamping the boss part.

[0028] 3. The equipment used in this invention includes: a CNC lathe, a five-axis machining center, and a fitter's table;

[0029] 4. Based on the designed part sketches, machine the corresponding parts and assemble them;

[0030] 5. The present invention loads the assembled fixture onto the worktable of a five-axis machining center, imports the prepared CNC program into the machine tool, establishes the machining coordinate system and clamps the tool, and then starts the machine tool to process the part. The entire operation process is simple and efficient.

[0031] 6. The actual machining effect of the convex part is good. The machining fixture designed and manufactured by this invention can effectively realize the positioning and clamping of the part. The programming method of this invention can create an efficient and concise five-axis linkage machining program to achieve high-quality and stable machining of the part.

[0032] This invention explores a machining method for the three-dimensional spatial surface of a boss-type part, designs a reliable, effective, and cost-effective machining fixture, and explores a five-axis linkage spatial surface programming method for boss parts. The cost of the machining fixture is less than 2,000 yuan per set, making it suitable for widespread promotion and application. Attached Figure Description

[0033] Figure 1 This is a drawing of the outline of an aircraft engine mounting bracket.

[0034] Figure 2 yes Figure 1 View from the H direction;

[0035] Figure 3 This is a schematic diagram of the assembly of the fixture and the boss parts;

[0036] Figure 4It is a FF view with 3 cross sections;

[0037] Figure 5 This is a drawing of the mandrel part;

[0038] Figure 6 yes Figure 5 Mid-section AA view;

[0039] Figure 7 This is a schematic diagram of the UG 3D programming model processing of the boss part;

[0040] Figure 8 It is a 3D assembly drawing of the fixture and boss parts;

[0041] Figure 9 This is a schematic diagram of the toolpath for the three-dimensional profile of the boss part;

[0042] Figure 10 These are schematic diagrams of two flow curves used in the five-axis linkage programming of the boss part;

[0043] 1-Mandrel, 2-Screw, 3-Nut, 4-Washer, 5-Boss part, 6-Upper profile. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0045] In order to solve Figure 1 and Figure 2 The key to solving the machining problem of the spatial surface (upper surface 6 is a spatial curved surface) of the boss part shown lies in the design and manufacture of the machining fixture and the implementation of the five-axis linkage machining method.

[0046] like Figure 3 , 4 As shown in Figures 5, 6, and 8, the present invention designs the machining fixture for the boss part 5 into two parts: one part is the fixture base, i.e., the mandrel 1, which is used for supporting and angular positioning of the boss part 5; the other part is the clamping structure, i.e., the screw 2 and the nut 3, which is used to clamp the end face of the boss part 5.

[0047] Five-axis linkage machining mainly involves the processing of UG programming models and five-axis linkage programming methods. UG programming model processing is a crucial step in multi-axis machining, ensuring continuous and uninterrupted CNC toolpaths and reducing the risks of tool skipping, interference, and collisions. Five-axis linkage programming methods primarily focus on the control of the tool axes.

[0048] Design of machining fixtures: such as Figure 3 and Figure 4 The fixture design comprises two parts: a base (mandrel 1) and a clamping part (screw 2 and nut 3). Because the upper surface 6 of the machined part 5 has a positional relationship with other parts, angular positioning is necessary during the machining of the boss part 5. The fixture is used for part support and angular positioning. UG differential processing can be used during the design, employing the boss part 5 as a differential tool to obtain the three-dimensional spatial dimensions of the part, thus improving the efficiency and accuracy of the fixture design. The groove root of the fixture mandrel 1 (…) Figure 4 ) Root cleaning must be performed to prevent interference between the bottom edge of the boss part 5 and the root of the fixture, and the bottom surface of the fixture groove ( Figure 4 The C-surface is used for part support, and the inner side of the groove ( Figure 4 The middle D surface is used for angular positioning, and the inner side of the clamp groove ( Figure 4 There should be a gap of 0.03 to 0.05 mm between the middle D surface and the square outer surface of the base of the boss part 5, and finally the boss part is pressed by the pressing part.

[0049] like Figure 4 and Figure 8 The fixture is used as follows:

[0050] 1) Screw the lower end of the screw 2 into the internal threaded hole of the mandrel 1 of the fixture;

[0051] 2) Insert the boss part 5 into the groove cavity of the mandrel 1 of the fixture;

[0052] 3) Install the washer 4 onto the screw 2;

[0053] 4) Screw the nut 3 into the upper external thread of the screw 2 to tighten the boss part 5.

[0054] The fixture base corresponds to the design and manufacture of mandrel 1. The dimensions of mandrel 1 are shown below. Figure 5 and Figure 6 As shown.

[0055] The clamping part of the fixture mainly consists of screw 2, washer 4, and nut 3. Screw 2, washer 4, and nut 3 are all standard parts and can be used directly. The manufacturing process of the fixture mandrel 1 is as follows:

[0056] 1) Use one piece of Φ65X60 raw material, made of 45 steel;

[0057] 2) Flatten the end face and machine the outer circle: Machine the Φ30 outer circle and chamfer it;

[0058] 3) Turn the machine around, clamp the Φ30 outer diameter, flatten the end face, and machine the Φ60 outer diameter;

[0059] 4) On a five-axis machining center, mill the upper end face (upper inclined surface), groove (inner cavity), drill holes and tap threads;

[0060] 5) Deburr.

[0061] Equipment requirements: CNC lathe, five-axis machining center and fitter's platform.

[0062] Processing of CNC programming models: such as Figure 1 and Figure 2 The bottom surface of the boss part 5 is rectangular and irregular in shape. Direct UG programming causes frequent toolpath jumps, leading to numerous risks during machining. A circle is the ideal programming shape. Therefore, a solid circular base is used to enclose the base of the boss part 5. A schematic diagram of the 3D model processing in UG CNC programming is shown below. Figure 7 In the figure, the upper surface 6 is enclosed in a cylindrical outline, forming a circular boundary outline.

[0063] Five-axis linkage programming method:

[0064] 1) Establish the coordinate system for part machining;

[0065] 2) Select the part to be processed, and select the blank to be processed;

[0066] 3) Create the machining tool: D4 carbide ball end mill;

[0067] 4) Select the processing location;

[0068] 5) Select the driving method: Streamline driving, select two flow curves, such as... Figure 10 As shown, the two flow curves are thickened line A and thickened line B, respectively, which correspond to the outer contour line of the upper surface 6 after it is expanded into a circular boundary, and the outer contour line of the upper end of the cylindrical surface N.

[0069] 6) Select projection method: perpendicular to the driving body;

[0070] 7) Select the tool axis control method: interpolation vector;

[0071] 8) Control parameters such as speed and feed.

[0072] See the schematic diagram of the five-axis linkage machining toolpath for part 5 of the boss. Figure 9 . Figure 9 In the process, the toolpath for machining the boss part 5 is continuous and uninterrupted, with only one feed. It feeds from the outermost edge and moves counterclockwise around the circumference (as indicated by the arrow in the figure) towards the inner circle. After continuous cutting, it retracts from the inner side (at point N on the cylindrical surface) along the dotted line.

[0073] The contents not described in detail in this specification are prior art known to those skilled in the art. Although the invention has been described in detail in specific embodiments to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various modifications are obvious as long as they are within the spirit and scope of the invention as defined and determined by the claims. All inventions utilizing the concept of this invention are within the protection scope of this invention.

Claims

1. A method for machining the spatial surface of a boss part, characterized in that: The boss component includes, The base includes an upper surface (6), which is a curved surface and has a rectangular outer contour. The protrusion is connected to the upper molded surface (6) and includes a coaxial cylindrical surface M and a cylindrical surface N. The outer diameter of the cylindrical surface M is greater than the outer diameter of the cylindrical surface N. The cylindrical surface N is located between the cylindrical surface M and the upper molded surface (6) and is connected to the upper molded surface (6). The angle between the cylindrical surface M, the cylindrical surface N and the upper molded surface (6) is not equal to 90 degrees. A through hole, which penetrates the base and the protrusion, and is coaxial with cylindrical surfaces M and N; The machining fixtures used include: The mandrel (1) is a rotating structure. The upper end face of the mandrel (1) forms a first included angle with the axis of rotation. The first included angle is equal to the included angle between the upper profile (6) of the boss part (5) and the cylindrical surface M and the cylindrical surface N. A groove is opened on the upper end face of the mandrel (1). The bottom surface of the groove is parallel to the upper end face of the mandrel (1). A threaded hole is opened on the bottom surface of the groove. The central axis of the threaded hole coincides with the axis of rotation of the mandrel (1). The screw (2) is inserted into the through hole of the boss part (5) and its lower end is connected to the threaded hole on the bottom surface of the groove of the mandrel (1); Nut (3), the nut (3) is connected to the upper end of the screw (2) and pressed against the upper end of the cylindrical surface M of the boss part (5); The machining method employs five-axis linkage machining of the upper surface (6) of the boss part (5), and includes: The mounting steps for the boss part (5) are as follows: insert the base of the boss part (5) into the groove of the spindle (1), and connect the screw (2) through the through hole of the boss part (5) to the threaded hole in the groove. Then, use the nut (3) to press the boss part (5) from the upper end of the screw (2). Modeling steps for the convex part (5): When modeling, a cylindrical body is used to enclose the base, and the outer contour of the upper surface (6) is expanded from a rectangle to a circle. The five-axis linkage programming steps are as follows: the tool path is continuously and uninterruptedly fed from the outside to the inside along the circumference once, and the tool is retracted after continuous cutting. The streamline drive is adopted and the outer contour line after the upper surface (6) is expanded into a circular boundary is selected, and the outer contour line of the upper end of the cylindrical surface N is used as two flow curves.

2. The method for machining the spatial surface of a boss part according to claim 1, characterized in that: In the five-axis linkage programming steps, a ball end mill is used when creating the machining tool.

3. The method for machining the spatial surface of a boss part according to claim 1, characterized in that: In the five-axis linkage programming steps, the projection method is selected as perpendicular to the driving body.

4. The method for machining the spatial surface of a boss part according to claim 1, characterized in that: In the five-axis linkage programming steps, the tool axis control mode is selected as interpolation vector.

5. The method for machining the spatial surface of a boss part according to claim 1, characterized in that: The inner contour shape of the groove of the mandrel (1) is consistent with the outer contour shape of the upper surface (6).

6. The method for machining the spatial surface of a boss part according to claim 1, characterized in that: The inner contour dimension of the groove of the mandrel (1) is larger than the outer contour dimension of the upper surface (6), so that when the boss part (5) is placed in the groove and closely attached to the bottom surface of the groove, there is a gap between the circumferential surface of the base of the boss part (5) and the inner surface of the groove.

7. The method for machining the spatial surface of a boss part according to claim 1, characterized in that: The machining fixture also includes a gasket (4), which is sleeved on the screw (2) and installed between the nut (3) and the end face of the boss part (5).

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