A composite material T-shaped long stringer horizontal side chamfering processing method and processing tool

Abstract

The present invention provides a method and tool for chamfering the horizontal edge of a T-shaped long stringer of composite material. The tool body is provided with a stepped through hole and a plurality of formed blocks evenly distributed along the circumference for clamping a milling blade. A ring-type tight-fitting bearing is fitted onto the tool body after interference fit with the outer diameter of the bearing and is limited by a fixing bolt at the milling end. Another bearing is fitted onto the tool body from the other end and limited by a limiting bushing. A spring is fitted onto the fixing bolt at the clamping end and passes through the stepped hole of the tool body and is threadedly connected to the fixing bolt at the milling end passed through the other end. The fixing bolt at the clamping end can slide within the hole, and the spring presses on the steps of the stepped hole to provide a clamping force. The ring-type tight-fitting bearing is pulled out, and the horizontal edge of the long stringer is placed between the ring-type tight-fitting bearing and the bearing on the other side. The long stringer is clamped by the pressing force of the spring. While the chamfer is being processed, the ring-type tight-fitting bearing and the bearing rotate in the feed direction, achieving continuous clamping of the cutting part during the cutting process and ensuring the tightness of the cutting part.

Description

Technical Field

[0001] The invention belongs to the field of mechanical processing of aircraft composite material parts, and particularly relates to a method for processing the chamfering of the horizontal side of a composite material T-shaped long stringer and a processing tool. Background Art

[0002] As composite materials are increasingly used in aircraft bodies, the structures of composite parts are also constantly being updated. Traditionally, the long stringers on aircraft vertical tail panels mostly use I-shaped long stringers. In order to speed up the production rate and reduce the difficulty of the process, designers gradually tend to optimize the long stringers glued to the panel into a T-shaped structure, and use the automatic tape laying process to produce such T-shaped long stringers. Due to the certain thickness of the solidified long stringer lying edge during the bonding process, when the panel skin is cured, the thicker lying edge of the long stringer in contact with the skin is easy to sink into the thickness of the skin, and typical defects such as ply wrinkles are prone to appear near the surface of the skin. At the same time, due to the height difference of the edge excessive position, the pressurization effect is often not ideal, and defects such as pores are prone to appear after curing. Therefore, the designers have further optimized and added chamfers to the lying edge of the long stringer, so that the curing pressure at this position is uniform, ensuring the quality of part bonding.

[0003] The chamfers of the horizontal sides of T-shaped long girders cannot be formed directly during the automatic tape laying process, and can only be obtained through secondary processing after the parts are solidified. Manual milling of chamfers is difficult, and the milling accuracy cannot be guaranteed. The overall contour after processing is poor, the scrap rate is high, and the requirements of high-precision, high-efficiency and high-performance manufacturing cannot be met. Process personnel have to consider using CNC machining, but composite materials have poor processing technology due to their manufacturing methods. If they are not careful, defects such as delamination and burring of parts will occur, and the parts will be scrapped. The present invention provides a method and a machining tool for processing the chamfers of the horizontal sides of T-shaped long girders of composite materials. The above problems can be solved, the process can be carried out stably, and the product quality meets the acceptance requirements. Summary of the Invention

[0004] The ultimate purpose of the present invention is to provide a composite material T-shaped long beam horizontal chamfering processing method and processing tool, solve the T-shaped long beam horizontal chamfering processing quality, low efficiency, unstable production process problems, improve product qualification rate, save costs.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A composite material T-shaped long stringer horizontal chamfering processing tool, the processing tool comprises: a tool body 1, a clamping end fixing bolt 2, a spring 3, a limiting bushing 4, a ring tight fitting bearing 5, a bearing 6, and a milling end fixing bolt 7.

[0007] The tool body 1 is a cylindrical structure, with one end being the clamping end and the other end being the milling end. Several forming blocks are evenly distributed along the circumference near the end of the milling end. The forming blocks are triangular structures, and the inclination angle of the inclined surface is set according to the chamfer size of the lying edge. The forming blocks are used to fix the milling blades, and gaps are left between the forming blocks for chip removal. The tool body 1 has a built-in axial three-step stepped through hole, with the two ends being the large diameter section of the clamping end and the large diameter section of the milling end, and the middle part being the small diameter section.

[0008] The ring-fitting bearing 5 is a disc-shaped structure with a through hole in the center. The outer edge of the disc-shaped structure is a circular ring with a certain thickness. The size of the through hole in the center is adapted to the outer diameter of the cylindrical structure of the tool body 1. The ring-fitting bearing 5 is sleeved on the tool body 1 from the milling end side of the tool body 1. The two are clearance-fitted. The inner diameter of the outer edge of the circular ring away from the tool body 1 is interference-fitted with the outer diameter of the outer ring of the bearing 6.

[0009] There are two bearings 6, one of which has an outer diameter that is interference fit with the ring-fitting bearing 5, and is sleeved on the milling end side of the tool body 1 together with the ring-fitting bearing 5, and the inner hole of the bearing 6 is clearance-fitted with the tool body 1; the other bearing 6 is sleeved on the tool body 1 from the clamping end side of the tool body 1, and the two are clearance-fitted. A limiting sleeve 4 is fixed on the tool body 1 outside the bearing 6, which is used to limit the bearing 6 on the tool body 1. During the cutting process, the outer ring of the bearing 6 and the circular ring of the ring-fitting bearing 5 rely on the force of the spring 3 to assist in clamping and limiting the lying edge of the long beam.

[0010] The stud end of the clamping end fixing bolt 2 is made of external thread. After the spring 3 is put on the stud, the two are inserted into the stepped hole from the clamping end of the tool body 1 together, and are threadedly connected with the milling end fixing bolt 7 inserted from the other end. The stud of the clamping end fixing bolt 2 slides with the inner diameter of the small diameter section of the stepped hole, and the nut slides with the large diameter section of the clamping end of the stepped hole. One end of the spring 3 is pressed against the nut of the clamping end fixing bolt 2, and the other end is pressed against the step between the large diameter section and the small diameter section of the clamping end of the stepped hole, and it is always in a compressed state.

[0011] The stud of the milling end fixing bolt 7 penetrates into the large diameter section of the milling end of the stepped hole of the tool body 1 and slides together. It is threadedly connected with the clamping end fixing bolt 2. Due to the compression of the spring 3, the nut of the milling end fixing bolt 7 is pressed against the end face of the bearing 6 on the milling end side and restricts it on the tool body 1. When in use, the tight-fitting bearing 5 is pulled outward against the ring, and the bearing 6 on the milling end side is pulled out accordingly, and then the milling end fixing bolt 7 drives the clamping end fixing bolt 2 to move, further pressing Compress the spring 3 and place the lying edge of the long stringer between the bearing 6 on one side of the clamping end of the close-fitting bearing 5, loosen the close-fitting bearing 5, and rely on the pressing force of the spring 3 to achieve auxiliary clamping and limiting of the lying edge of the long stringer. At the same time, the close-fitting bearing 5 and the outer ring of the bearing 6 rotate with the feed movement of the tool body 1, forming a displacement in the feed direction, avoiding damage to the surface of the lying edge of the long stringer due to dry friction, ensuring that the lying edge of the long stringer is always in a clamped state during the milling process, preventing defects such as delamination, and ensuring the quality of chamfer milling.

[0012] Furthermore, the tool body 1 and the close-fitting bearing 5 are made of steel.

[0013] Furthermore, the milling blade is made of polycrystalline diamond, which has high hardness, good heat conductivity, and low friction coefficient, which can reduce cutting force. At the same time, it has low affinity with non-metallic materials, which helps to remove chips and ensure the cutting quality of parts, such as no burrs or flash.

[0014] A method for processing the chamfering of the horizontal edge of a T-shaped long stringer of composite material is realized based on the above-mentioned processing tool in combination with existing milling tooling and forming tooling. The processing method includes the following steps:

[0015] Step 1: Roughly cut the solidified long stringer blank 8 and leave a margin.

[0016] Step 2: Fix the milling tool 10 on the processing platform to ensure stable positioning.

[0017] Step 3: Position the rough-cut long stringer blank 8 according to the reserved positioning holes through the positioning pins 12 and clamp it on the milling tool 10 surface, and then use the disc-shaped pressing plate 11 to press it tightly to ensure that there is no movement during the milling process.

[0018] Step 4: Clamp the clamping end of the tool body 1 in the machining tool 9 on the machining equipment. After the tool is aligned, pull out the ring-fitting bearing 5 used for pressing at the end of the machining tool 9, and then pull out the fixing bolt 7 at the milling end, compressing the spring 3. Place the horizontal edge of the long string blank 8 between the ring-fitting bearing 5 and the bearing 6 on the clamping end side. Loosen the ring-fitting bearing 5. Under the action of the spring 3, the clamping effect is achieved to prevent machining delamination. During the machining process, the tool body 1 rotates while forming a displacement in the feed direction. The ring-fitting bearing 5 and the bearing 6 on the clamping end side rotate in the feed direction while clamping, thereby driving the entire machining tool 9 to move in the feed direction to achieve milling of the horizontal edge chamfer of the long string blank 8. During machining, rough machining chamfering is first performed, followed by semi-finishing chamfering, and finally finishing.

[0019] Step 5: Remove the processed long stringer blank 8, and mill the vertical edges and ends of the long stringer blank 8 according to the net size lines of the parts printed by the molding tool marking lines on the vertical edges and ends of the long stringer blank 8.

[0020] Step 6: Perform surface finishing and edge banding of the cut edges, and finally carry out other processes and deliver.

[0021] The beneficial effects of the present invention are:

[0022] The present invention adopts a processing tool to form the chamfer of the lying edge of the long stringer through rough and fine processing in one step. At the same time, an auxiliary clamping device on the processing tool is used to realize continuous clamping of the cutting part during the cutting process to ensure the tightness of the cutting part. At the same time, the PCD tool is used to ensure stable cutting, thereby greatly improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Overall isometric view of the chamfer milling process.

[0024] Figure 2 Schematic diagram of machining tool application.

[0025] Figure 3 Isometric diagram of the overall machining tool.

[0026] Figure 4 Schematic diagram of machining tool explosion.

[0027] Figure 5 Cutaway view of machining tool.

[0028] In the figure: 1 tool body; 2 clamping end fixing bolt; 3 spring; 4 limit bushing; 5 ring tight fitting bearing; 6 bearing; 7 milling end fixing bolt; 8 long string blank; 9 processing tool; 10 milling tool; 11 disc pressure plate; 12 positioning pin. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solution of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments improved or adjusted by ordinary technicians in this field fall within the scope of protection of the present invention.

[0030] A composite material T-shaped long stringer horizontal chamfering processing tool, the processing tool comprises: a tool body 1, a clamping end fixing bolt 2, a spring 3, a limit bushing 4, a ring tight fitting bearing 5, a bearing 6, a milling end fixing bolt 7, such as Figures 3 to 5 As stated.

[0031] The tool body 1 is a cylindrical structure made of steel, with one end being a clamping end and the other end being a milling end. There are 6 forming blocks evenly distributed along the circumference near the end of the milling end. The forming blocks are triangular structures, and the inclination angle of the inclined surface is set according to the chamfer size of the lying edge. The forming blocks are used to fix the milling blades. There is a gap between the forming blocks for chip removal. The milling blade is made of polycrystalline diamond (PCD), which has high hardness, heat conductivity, and a low friction coefficient to reduce cutting force. At the same time, it has low affinity with non-metallic materials, which helps to remove chips and ensure the cutting quality of parts, such as no burrs or flash. The tool body 1 has a built-in axial three-step stepped through hole, wherein the holes at both ends are the large diameter section of the clamping end and the large diameter section of the milling end, and the hole in the middle is the small diameter section.

[0032] The ring-fitting bearing 5 is made of steel and is a disc-shaped structure with a through hole in the center. The outer edge of the disc-shaped structure is a circular ring with a certain thickness. The size of the through hole in the center is adapted to the outer diameter of the cylindrical structure of the tool body 1. The ring-fitting bearing 5 is mounted on the tool body 1 from the milling end of the tool body 1. The two are clearance-fitted, and the inner diameter of the outer edge of the circular ring away from the tool body 1 is interference-fitted with the outer diameter of the outer ring of the bearing 6.

[0033] There are two bearings 6, one of which has an outer diameter that is interference fit with the ring-fitting bearing 5, and is sleeved on the milling end side of the tool body 1 together with the ring-fitting bearing 5, and the inner hole of the bearing 6 is clearance-fitted with the tool body 1; the other bearing 6 is sleeved on the tool body 1 from the clamping end side of the tool body 1, and the two are clearance-fitted. A limiting sleeve 4 is fixed on the tool body 1 outside the bearing 6, which is used to limit the bearing 6 on the tool body 1. During the cutting process, the outer ring of the bearing 6 and the circular ring of the ring-fitting bearing 5 rely on the force of the spring 3 to assist in clamping and limiting the lying edge of the long beam.

[0034] The stud end of the clamping end fixing bolt 2 is made of external thread. After the spring 3 is put on the stud, the two are inserted into the stepped hole from the clamping end of the tool body 1 together, and are threadedly connected with the milling end fixing bolt 7 inserted from the other end. The stud of the clamping end fixing bolt 2 slides with the inner diameter of the small diameter section of the stepped hole, and the nut slides with the large diameter section of the clamping end of the stepped hole. One end of the spring 3 is pressed against the nut of the clamping end fixing bolt 2, and the other end is pressed against the step between the large diameter section and the small diameter section of the clamping end of the stepped hole, and it is always in a compressed state.

[0035] The stud of the milling end fixing bolt 7 penetrates into the large diameter section of the milling end of the stepped hole of the tool body 1 and slides together. It is threadedly connected with the clamping end fixing bolt 2. Due to the compression of the spring 3, the nut of the milling end fixing bolt 7 is pressed against the end face of the bearing 6 on the milling end side and restricts it on the tool body 1. When in use, the tight-fitting bearing 5 is pulled outward against the ring, and the bearing 6 on the milling end side is pulled out accordingly, and then the milling end fixing bolt 7 drives the clamping end fixing bolt 2 to move, further pressing Compress the spring 3 and place the lying edge of the long stringer between the bearing 6 on one side of the clamping end of the close-fitting bearing 5, loosen the close-fitting bearing 5, and rely on the pressing force of the spring 3 to achieve auxiliary clamping and limiting of the lying edge of the long stringer. At the same time, the close-fitting bearing 5 and the outer ring of the bearing 6 rotate with the feed movement of the tool body 1, forming a displacement in the feed direction, avoiding damage to the surface of the lying edge of the long stringer due to dry friction, ensuring that the lying edge of the long stringer is always in a clamped state during the milling process, preventing defects such as delamination, and ensuring the quality of chamfer milling.

[0036] A method for chamfering the horizontal edge of a T-shaped long stringer of composite material is implemented based on the above-mentioned machining tool in conjunction with existing milling tooling and forming tooling, comprising the following steps:

[0037] Step 1: Use a manual cutting tool to roughly cut the horizontal edge of the solidified long stringer blank 8, leaving a margin of about 7mm.

[0038] Step 2: Fix the milling tool 10 on the five-axis machining platform to ensure stable positioning.

[0039] Step 3: Position the rough-cut long stringer blank 8 according to the reserved positioning holes through the positioning pins 12 and clamp it on the milling tool 10 surface, and then use the disc-shaped pressure plate 11 to press it tightly to ensure that there is no movement during the milling process. Figure 1 and Figure 2 shown.

[0040] Step 4: Clamp the clamping end of the tool body 1 in the machining tool 9 onto the machining equipment. After tool alignment, pull out the clamping ring bearing 5 used for pressing the end of the machining tool 9, and then pull out the fixing bolt 7 of the milling end, compressing the spring 3. Place the horizontal edge of the long string blank 8 between the clamping ring bearing 5 and the bearing 6 on the clamping end side. Release the clamping ring bearing 5. Under the action of the spring 3, the clamping effect is achieved to prevent machining delamination. During the machining process, the tool body 1 rotates and forms a displacement in the feed direction. The clamping ring bearing 5 and the bearing 6 on the clamping end side rotate in the feed direction while clamping, thereby driving the entire machining tool 9 to move in the feed direction, achieving milling of the horizontal edge chamfer of the long string blank 8. During machining, first reserve a 4mm allowance for rough machining chamfering, then reserve a 1mm allowance for semi-finishing chamfering, and finally reserve a 0 or 2mm allowance for finishing.

[0041] Step 5: Remove the processed long stringer blank 8 and send it to the manual milling process to mill the vertical edges and ends of the long stringer blank 8 according to the net size lines of the parts printed by the molding tool engraving lines.

[0042] Step 6: Finish the surface as required and perform edge banding on the cut edges, then proceed with other processes and deliver.

[0043] The above-described embodiments merely express the implementation methods of the present invention, but should not be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A composite material T-shaped long stringer horizontal chamfering tool, characterized in that: The machining tool comprises: a tool body (1), a clamping end fixing bolt (2), a spring (3), a limiting bushing (4), a ring-fitting bearing (5), a bearing (6), and a milling end fixing bolt (7); The tool body (1) is a cylindrical structure, one end of which is a clamping end and the other end of which is a milling end. The milling end is close to the end position and is evenly distributed along the circumference of a plurality of forming blocks. The forming blocks are triangular structures, and the inclination angle of the inclined surface is set according to the chamfer size of the horizontal side. The forming blocks are used to fix the milling blade. The tool body (1) has a built-in axial three-step stepped through hole, the two ends of which are respectively a clamping end large diameter section and a milling end large diameter section, and the middle part is a small diameter section. The ring-fitting bearing (5) is a disc-shaped structure with a through hole in the center. A circular ring is provided on the outer edge of the disc-shaped structure. The size of the through hole in the center of the ring-fitting bearing (5) is adapted to the outer diameter of the cylindrical structure of the tool body (1). The ring-fitting bearing (5) is sleeved on the tool body (1) from the milling end side of the tool body (1). The two are clearance-fitted. The inner diameter of the circular ring on the outer edge of the bearing (6) is interference-fitted with the outer diameter of the outer ring of the bearing away from the tool body (1). There are two bearings (6), one of which has an outer diameter that is interference-fitted with the ring-tightening bearing (5), and is sleeved on the milling end side of the tool body (1) together with the ring-tightening bearing (5), and the inner hole of the bearing (6) is clearance-fitted with the tool body (1); the other bearing (6) is sleeved on the tool body (1) from the clamping end side of the tool body (1), and the two are clearance-fitted. A limited sleeve (4) is fixedly mounted on the tool body (1) outside the bearing (6) for limiting the bearing (6) on the tool body (1). During the cutting process, the outer ring of the bearing (6) and the circular ring of the ring-tightening bearing (5) jointly rely on the force of the spring (3) to assist in clamping and limiting the horizontal edge of the long stringer; The stud end of the clamping end fixing bolt (2) is made of external thread. After the spring (3) is sleeved on the stud, the two are inserted into the stepped through hole from the clamping end of the tool body (1) and are threadedly connected with the milling end fixing bolt (7) inserted from the other end. The stud of the clamping end fixing bolt (2) is slidably matched with the inner diameter of the small diameter section of the stepped through hole, and the nut is slidably matched with the large diameter section of the clamping end of the stepped through hole. One end of the spring (3) is pressed on the nut of the clamping end fixing bolt (2), and the other end is pressed on the step between the large diameter section and the small diameter section of the clamping end of the stepped through hole, and it is always in a compressed state. The stud of the milling end fixing bolt (7) penetrates into the large diameter section of the milling end of the stepped through hole of the tool body (1) and is slidably fitted, and is threadedly connected to the clamping end fixing bolt (2). Due to the pressing action of the spring (3), the nut of the milling end fixing bolt (7) is pressed against the end face of the bearing (6) on one side of the milling end and is restricted on the tool body (1).

2. A composite material T-shaped long stringer horizontal edge chamfering tool according to claim 1, characterized in that: Gaps are left between the forming blocks on the tool body (1) for chip removal.

3. A composite material T-shaped long stringer horizontal edge chamfering tool according to claim 1, characterized in that: The tool body (1) and the close-fitting bearing (5) are made of steel.

4. A composite material T-shaped long stringer horizontal edge chamfering tool according to claim 1, characterized in that: The milling blade is made of polycrystalline diamond.

5. A method for chamfering the horizontal edge of a T-shaped long stringer of composite material, which is realized by using the machining tool according to any one of claims 1 to 4 in combination with a milling tool, characterized in that: The processing method comprises the following steps: Step 1, rough cut the solidified long stringer (8) and leave a margin; Step 2, fix the milling tool (10) on the processing platform to ensure stable positioning; Step 3, positioning and clamping the rough-cut long stringer (8) on the milling tool (10) profile and pressing it tightly; Step 4, clamp the clamping end of the tool body (1) in the processing tool (9) on the processing equipment, and after completing the tool setting, pull out the ring-fitting bearing (5) used for pressing the end of the processing tool (9), and then pull out the fixing bolt (7) of the milling end, and compress the spring (3); place the horizontal side of the long stringer (8) between the ring-fitting bearing (5) and the bearing (6) on the clamping end side, loosen the ring-fitting bearing (5), and achieve the clamping effect under the action of the spring (3); during the processing, the tool body (1) rotates and forms a displacement in the feed direction, and the ring-fitting bearing (5) and the bearing (6) on the clamping end side rotate in the feed direction while clamping, thereby driving the entire processing tool (9) to move along the feed direction, thereby realizing the milling of the horizontal chamfer of the long stringer (8); Step 5, remove the processed long stringer (8), and mill the vertical edges and ends of the long stringer; Step 6: Surface finishing and edge banding of the cut edges are performed, and finally other processes are carried out and the product is delivered.

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