Composite material hole making method
By combining drilling and milling and utilizing the tool eccentricity for radial milling, the problems of delamination and tearing during the hole making process of composite materials are solved, the hole making efficiency is improved and the cost is reduced.
Patent Information
- Application Number
- CN202510054307.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2025-10-17
AI Technical Summary
In the process of making holes in composite materials, the existing technology is difficult to avoid the occurrence of delamination and tearing defects, while increasing production costs and reducing hole-making efficiency.
A method combining drilling and milling is adopted. After axial drilling, radial milling is performed using the eccentricity of the tool to gradually expand the hole diameter, ensure that the hole outlet is not squeezed by axial force, avoid tearing, and reduce the use of support materials.
It effectively avoids the occurrence of delamination and tearing defects, improves hole-making efficiency, and reduces production costs.
Smart Images
Figure CN120791893A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of material processing, in particular to a composite material hole making method. BACKGROUND
[0002] A large number of carbon fiber composites are used in aerospace vehicles, and the assembly between laminated components usually adopts bolt and rivet connection, which requires processing a large number of connecting holes. The composite material is usually formed by layer-by-layer laying and curing of prepreg, and the interlayer bonding force is low due to the use of resin for bonding between layers. During hole making, the fibers near the exit side of the composite material opening are deformed under the action of the axial force of the tool, the interlayer resin base is damaged, and defects such as delamination and tearing are formed, which affects the quality of assembly.
[0003] Currently, there are two ways for composite material hole making. One is to use a drill bit for drilling, which generates a large axial force. The other is to use a end mill to mill a hole along a spiral trajectory, although the axial force is reduced, but still exists. If a support is added at the exit side of the composite material, the carbon fibers are not easy to deform under the action of the support when the tool cuts to the exit side, the interlayer resin base is not easy to be damaged, and delamination and tearing can be avoided, but in actual production, there are many composite materials that cannot be added with supports, and adding supports will greatly increase the production cost and reduce the hole making efficiency.
[0004] Therefore, a composite material hole making method is needed to solve the above problems. SUMMARY
[0005] The purpose of the present application is to provide a composite material hole making method which can avoid the generation of defects such as delamination and tearing, and save cost and improve hole making efficiency.
[0006] To achieve this purpose, the present application adopts the following technical scheme:
[0007] The composite material hole making method comprises the following steps:
[0008] S1, determining the diameter D1 of the pre-hole according to the diameter D of the hole to be processed, D1 < D;
[0009] S2, selecting a tool and clamping the workpiece and the tool on the machining equipment;
[0010] S3, making the tool coaxial with the pre-hole, the offset e1 of the tool is 0, and the workpiece is drilled along the axial direction until the pre-hole is processed, and the first cutting part of the tool protrudes relative to the pre-hole, and the second cutting part of the tool corresponds to the hole wall of the pre-hole along the axial direction;
[0011] S4, adjust the eccentricity of the tool by single or multiple times, and mill the hole with a diameter of D by using the second cutting part.
[0012] In some embodiments, in the step S1, the diameter D1 of the preformed hole satisfies D1≤D-2K, where K is the maximum radial single-side width of the damaged area caused by the axial milling.
[0013] In some embodiments, in the step S2, the tool comprises a tool holder, the first cutting part and the second cutting part, and the length L2 of the second cutting part satisfies L2>L, where L is the thickness of the workpiece.
[0014] In some embodiments, the diameter d1 of the first cutting part satisfies d1=D1.
[0015] In some embodiments, the diameter d1 of the first cutting part is greater than the diameter d2 of the second cutting part.
[0016] In some embodiments, the first cutting part comprises a front cutting edge and a first side edge, and the second cutting part comprises a second side edge.
[0017] In some embodiments, the step S4 comprises the following steps:
[0018] S41, the eccentricity of the tool is adjusted to e2=e1+(d1-d2) / 2, where d1 is the diameter of the first cutting part of the tool, and d2 is the diameter of the second cutting part of the tool;
[0019] S42, the radial single-feeding amount △e is determined radially;
[0020] S43, if ei+△e
[0021] S44, repeat the step S43 until ei+△e≥e, and then proceed to the next step;
[0022] S45, the eccentricity of the tool is adjusted to e=(D-d2) / 2, the hole is milled by using the second cutting part, a through hole with a diameter of D and coaxial with the preformed hole is milled, and a to-be-machined hole is obtained, and the machining is completed.
[0023] In some embodiments, in the step S42, the single-feeding amount △e is determined according to the material properties of the workpiece and the milling test.
[0024] In some embodiments, the step S4 comprises the following steps:
[0025] S41, the eccentricity of the cutter is adjusted to e2=e1+(d1-d2) / 2, wherein d1 is the diameter of the first cutting part of the cutter, and d2 is the diameter of the second cutting part of the cutter;
[0026] S42, the cutter eccentricity e=(D-d2) / 2 when machining the hole is calculated, and the radial feed speed f=(e-e2) / n is determined, wherein n is the revolution number of the cutter;
[0027] S43, if e2+f*ni
[0028] S44, the step S43 is repeated until e2+f*ni≥e, and then the next step is entered;
[0029] S45, the radial feed of the cutter is stopped, and the revolution of the cutter is continued to rotate at least one circle to obtain the hole to be machined.
[0030] In some embodiments, in the step S42, the radial feed speed f is determined according to the material properties of the workpiece and the milling test, and meanwhile, the revolution number n of the cutter should be an integer.
[0031] Advantages of the present application:
[0032] The composite material hole machining method provided by the present application determines the diameter D1 of the preformed hole according to the diameter D of the hole to be machined, selects a cutter, clamps the workpiece and the cutter on a machining equipment, makes the cutter coaxial with the preformed hole, sets the eccentricity e1 of the cutter to 0, and performs drilling on the workpiece in the axial direction until the preformed hole is machined, and the first cutting part of the cutter protrudes relative to the preformed hole, and the second cutting part of the cutter corresponds to the hole wall of the preformed hole in the axial direction, adjusts the eccentricity of the cutter once or multiple times, and uses the second cutting part to mill the hole with a diameter of D in the radial direction. In the above manner, the drilling and milling cooperation is adopted to ensure the efficiency of hole machining. Moreover, the feed direction of the cutter is changed from the axial direction to the radial direction, so that the hole outlet of the workpiece is no longer extruded by the axial force, and even if the hole outlet of the workpiece is not supported, tearing and other defects can also be effectively avoided. Moreover, since the supporting material is not needed to be arranged, the cost can be saved. BRIEF DESCRIPTION OF DRAWINGS
[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from the contents of the embodiments of the present application and these drawings without any creative effort.
[0034] Figure 1 is a flow chart of a composite material hole making method of the present application;
[0035] Figure 2 is a schematic diagram of a tool in a composite material hole making method of the present application;
[0036] Figure 3 is a schematic diagram of one of the milling hole modes in a composite material hole making method of the present application;
[0037] Figure 4 is a schematic diagram of the feed trajectory of one of the milling hole modes in a composite material hole making method of the present application.
[0038] In the drawings:
[0039] 1, first cutting part; 2, second cutting part; 3, tool shank; 100, workpiece. DETAILED DESCRIPTION
[0040] Before any embodiments of the present application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above-described drawings.
[0041] In the present application, the terms "comprise", "contain", "have" or any other variant thereof are intended to cover non-exclusive inclusions, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of another identical element in the process, method, article or device including the element.
[0042] In the present application, the terms "connection", "combination", "coupling", "mounting" can be direct connection, combination, coupling or mounting, or indirect connection, combination, coupling or mounting. Among them, for example, direct connection refers to the connection of two parts or components without the need for an intermediate part, and indirect connection refers to the connection of two parts or components with at least one intermediate part. In addition, "connection" and "coupling" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.
[0043] In the present application, it will be understood by those of ordinary skill in the art that the functions performed by the components can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by the parts can also be performed by one part, one component, or a combination of multiple parts.
[0044] In the present application, the terms "upper", "lower", "left", "right", "front", "back", and the like are described in the orientation and positional relationship shown in the drawings, and should not be understood as limiting the embodiments of the present application. In addition, it is also understood in the context that when referring to one element connected to another element "on" or "under", it can be directly connected to another element "on" or "under", or indirectly connected to another element "on" or "under" through an intermediate element. It should also be understood that the terms "upper", "lower", "left", "right", "front", "back", and the like not only represent the positive direction, but also can be understood as the side direction. For example, the lower side can include the directly below, left below, right below, front below, and back below, etc.
[0045] In the process of drilling holes in workpieces made of composite materials, in order to avoid defects such as delamination and tearing of the workpiece, save costs, and improve drilling efficiency, as shown in Figures 1-4 The present application provides a composite material drilling method. The composite material drilling method comprises the following steps:
[0046] S1, determining the diameter D1 of the pre-drilled hole according to the diameter D of the hole to be machined, D1 < D;
[0047] S2, selecting a tool and clamping the workpiece 100 and the tool on the machining equipment;
[0048] S3, coaxially aligning the tool with the pre-drilled hole, the offset e1 of the tool is 0, and the workpiece 100 is drilled along the axial direction until the pre-drilled hole is machined, and the first cutting part 1 of the tool protrudes relative to the pre-drilled hole, and the second cutting part 2 of the tool corresponds to the hole wall of the pre-drilled hole along the axial direction;
[0049] S4, adjusting the eccentricity of the tool once or multiple times, and using the second cutting part 2 to mill a hole with a diameter D along the radial direction.
[0050] By the above manner, the drilling and milling cooperation mode is adopted to ensure the efficiency of hole making. Moreover, by changing the tool feeding direction, the axial direction is changed to radial milling, so that the hole exit of the workpiece 100 is no longer extruded by the axial force, and even if the hole exit of the workpiece 100 has no support, tearing and other defects can also be effectively avoided. Since there is no need to arrange supporting materials, the cost can be saved. Moreover, in the prior art, since the material removal in the hole making process mainly relies on the end edge of the tool, the end edge wears too fast, the exit defects gradually increase, and after the tip of the end edge is worn, the hole diameter is significantly reduced under the action of the radial force. By adopting the hole making mode, even if the end edge is worn to cause defects at the exit, the defects can also be removed in the radial milling process, so that the quality of hole making is ensured.
[0051] In some embodiments, in step S1, the diameter D1 of the preformed hole needs to satisfy: D1≤D-2K, wherein K is the maximum radial single-side width of the damage area generated by the axial milling. Specifically, the specific value of K is determined by experiments and experience. By the above manner, the influence of the damage area caused in the preformed hole process can be reduced, and in the subsequent milling process, the damage area can be effectively removed, so that the quality of the formed hole after hole making is ensured.
[0052] In some embodiments, in step S2, the tool includes a tool handle 3, a first cutting part 1 and a second cutting part 2, and the length L2 of the second cutting part 2 needs to satisfy: L2>L, wherein L is the thickness of the workpiece 100. By the above manner, after the first cutting part 1 protrudes relative to the preformed hole, the second cutting part 2 can effectively mill the inner wall surface of the entire preformed hole.
[0053] In some embodiments, the diameter d1 of the first cutting part 1 satisfies d1=D1. In the process of opening the preformed hole, the first cutting part 1 can be opened in place at one time, so as to process the preformed hole with a diameter of D1.
[0054] In some embodiments, the diameter d1 of the first cutting part 1 is greater than the diameter d2 of the second cutting part 2. By the above setting, the second cutting part 2 is facilitated to enter the preformed hole for subsequent milling operation.
[0055] In some embodiments, the first cutting part 1 includes a front end cutting edge and a first side edge, and the second cutting part 2 includes a second side edge. In the process of opening the preformed hole, the front end cutting edge of the first cutting part 1 drills, and the first side edge cuts the hole wall. In the subsequent hole expansion of the preformed hole, the second side edge of the second cutting part 2 performs milling operation.
[0056] As shown in Figure 3 and Figure 4 In some embodiments, step S4 includes the following steps:
[0057] S41, the eccentricity of the tool is adjusted to e2 = e1 + (d1-d2) / 2, where d1 is the diameter of the first cutting part 1 of the tool, and d2 is the diameter of the second cutting part 2 of the tool;
[0058] S42, the radial single feed amount △e is determined;
[0059] S43, if ei+△e < e, the eccentricity of the tool is adjusted to e(i+1) = ei+△e, and the second cutting part 2 of the tool is used to mill a through hole coaxial with the preformed hole, with a diameter of Di, where ei is the eccentricity of the tool in the previous hole milling, e(i+1) is the eccentricity of the tool in the current hole milling, e is the eccentricity of the tool in the finished hole, and i = 2, 3, 4, 5, …;
[0060] S44, repeat step S43 until ei+△e≥e, and then proceed to the next step;
[0061] S45, the eccentricity of the tool is adjusted to e = (D-d2) / 2, and the second cutting part 2 is used to mill the hole to obtain a through hole with a diameter of D coaxial with the preformed hole, and the finished hole is obtained after the machining is completed. By the above-mentioned way, the preformed hole is gradually expanded to the finished hole in the form of concentric circles, and the machining of the finished hole is completed. Through multiple milling, the machining accuracy can be guaranteed.
[0062] In some embodiments, in step S42, the radial single feed amount △e is determined according to the material properties of the workpiece 100 and the milling test. By adjusting the single feed amount △e flexibly in the above-mentioned way, the milling of the corresponding material can be guaranteed.
[0063] The following is a specific embodiment:
[0064] Calculate the diameter D1 of the preformed hole: according to the diameter D = 20 mm of the finished hole to be machined, and the maximum radial single side width K = 3.4 mm of the damage area generated by the axial hole milling obtained by experiment and material properties combined with experience, then D1 satisfies: D1≤D-2K, and the specific value of D1 is determined according to the actual situation, and D1 = 13 mm is obtained.
[0065] Select the tool: the tool includes a first cutting part 1, a second cutting part 2 and a tool handle 3. The length L2 of the second cutting part 2 needs to satisfy L2>L=40mm, L2=50mm, the diameter d1 of the first cutting part 1 satisfies d1=D1=13mm, and the diameter d2 of the second cutting part 2 satisfies d2
[0066] Clamp the workpiece 100 and the tool; the workpiece 100 to be machined is a carbon fiber reinforced resin matrix composite material.
[0067] The axis of the tool is coincided with the axis of the hole to be machined, the device drives the tool to drill a preformed hole with a diameter of D1=13mm from the entrance side along the axial direction until the first cutting part 1 of the tool protrudes relative to the exit side of the preformed hole, and the preformed hole wall is cut within the cutting range of the second cutting part 2.
[0068] The eccentricity of the tool is adjusted to e2=e1+(d1-d2) / 2=0.5mm; the radial single feed amount Δe=0.1mm is determined; when e2+Δe=0.6mm
[0069] In some embodiments, the preformed hole can also be expanded to form the hole by using the tool path of the spiral curve.
[0070] Step S4 includes the following steps:
[0071] S41, the eccentricity of the tool is adjusted to e2=e1+(d1-d2) / 2, where d1 is the diameter of the first cutting part 1 of the tool, and d2 is the diameter of the second cutting part 2 of the tool;
[0072] S42, the eccentricity e=(D-d2) / 2 of the tool when machining to the hole is calculated, and the radial feed speed f=(e-e2) / n is determined, where n is the number of revolutions of the tool;
[0073] S43, if e2+f*ni
[0074] S44, repeat step S43 until e2+f*ni≥e, and then proceed to the next step;
[0075] S45, the radial feed of the tool is stopped, and the revolution of the tool continues to rotate at least one revolution to obtain the hole to be machined. By the above-mentioned manner, the preformed hole can be milled quickly by using the continuous tool path until it is expanded to the hole.
[0076] In some embodiments, in step S42, the radial feed speed f is determined according to the material properties of the workpiece 100 and the milling test, while the number of revolutions of the tool n should be an integer. By flexibly adjusting the radial feed speed f in the above manner, the milling of the corresponding material can be ensured.
[0077] A specific embodiment is described below:
[0078] The diameter D1 of the preformed hole is calculated: according to the diameter D = 20 mm of the hole to be machined, and the maximum radial single-sided width K = 3.4 mm of the damage area generated by axial milling of the hole obtained by experiment and material properties combined with experience, then D1 satisfies: D1 ≤ D-2K, and the specific value of D1 is determined according to the actual situation, and D1 = 13 mm is obtained.
[0079] Selecting the tool: the tool includes a first cutting part 1, a second cutting part 2, and a tool shank 3. The length L2 of the second cutting part 2 needs to satisfy L2 > L = 40 mm, L2 = 50 mm, the diameter d1 of the first cutting part 1 satisfies d1 = D1 = 13 mm, and the diameter d2 of the second cutting part 2 satisfies d2 < d1, d2 = 12 mm. The first cutting part 1 of the tool is fed axially to protrude from the outlet side of the preformed hole, and the thickness L of the workpiece 100 is within the cutting range of the second cutting part 2.
[0080] Clamping the workpiece 100 and the tool; the workpiece 100 to be machined is a carbon fiber reinforced resin matrix composite material.
[0081] The axis of the tool is coincided with the axis of the hole to be machined, and the equipment drives the tool to drill a preformed hole with a diameter of D1 = 13 mm from the inlet side along the axial direction, until the first cutting part 1 of the tool protrudes from the outlet side of the preformed hole, and the hole wall of the preformed hole is within the cutting range of the second cutting part 2.
[0082] The eccentricity of the tool is adjusted to e2 = e1 + (d1-d2) / 2 = 0.5 mm; the eccentricity of the tool when machining to the hole e = (D-d2) / 2 = 4 mm is calculated, the radial feed speed of the tool revolution f = 0.1 mm / r is obtained according to the material properties of the workpiece 100 and the milling test, and the number of revolutions of the tool n = (e-e2) / f = 35;
[0083] S23, e2+f*n1=0.6mm < e=4mm, then n2=n1+1=2, the eccentricity of the tool continues to increase at a uniform speed, and the second cutting part 2 of the tool is used to mill the hole; e2+f*n2=0.7mm < e=4mm, then n3=n2+1=3, the above steps are repeatedly performed until n35=n34+1=35, e2+f*n35=4mm, at this time, the radial feed of the tool stops, and the revolution of the tool continues for at least one revolution, and the hole to be machined is obtained.
[0084] Obviously, the above embodiments of the present application are merely example for clearly explaining the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and also impossible to enumerate all the embodiments. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.
Claims
1. A method for making holes in a composite material, characterized in that: The steps include: S1, determine the diameter D1 of the prefabricated hole according to the diameter D of the hole to be processed, D1 <D; S2, selecting a tool, and clamping the workpiece (100) and the tool on a processing device; S3, aligning the tool with the prefabricated hole, setting the tool offset e1 to 0, and drilling the workpiece (100) in the axial direction until the prefabricated hole is formed, with the first cutting portion (1) of the tool extending relative to the prefabricated hole and the second cutting portion (2) of the tool corresponding to the wall of the prefabricated hole in the axial direction; S4, adjusting the eccentricity of the tool once or multiple times, and using the second cutting part (2) to mill the hole with a diameter of D in the radial direction.
2. The composite material hole making method according to claim 1, characterized in that: In step S1 , the diameter D1 of the prefabricated hole must satisfy: D1 ≤ D-2K, where K is the maximum radial width of a single side of the damaged area generated by axial milling.
3. The composite material hole making method according to claim 1, characterized in that: In step S2, the tool comprises a tool handle (3), the first cutting portion (1) and the second cutting portion (2), and the length L2 of the second cutting portion (2) needs to satisfy: L2>L, where L is the thickness of the workpiece (100).
4. The composite material hole making method according to claim 1, characterized in that: The diameter d1 of the first cutting portion (1) satisfies d1=D1.
5. The composite material hole making method according to claim 1, characterized in that: The diameter d1 of the first cutting portion (1) is greater than the diameter d2 of the second cutting portion (2).
6. The composite material hole making method according to claim 1, characterized in that: The first cutting portion (1) comprises a front cutting edge and a first side edge, and the second cutting portion (2) comprises a second side edge.
7. The composite material hole making method according to claim 1, characterized in that: The step S4 comprises the following steps: S41, the eccentricity of the tool is adjusted to e2=e1+(d1-d2) / 2, wherein d1 is the diameter of the first cutting portion (1) of the tool, and d2 is the diameter of the second cutting portion (2) of the tool; S42, determining a radial single feed amount Δe; S43, if ei + Δe < e, the eccentricity of the tool is adjusted to e(i+1) = ei + Δe, and a through hole coaxial with the prefabricated hole is milled using the second cutting portion (2) of the tool, wherein ei is the eccentricity of the tool during the previous milling, e(i+1) is the eccentricity of the tool during the current milling, and e is the eccentricity of the tool during the hole processing, and i = 2, 3, 4, 5, ...; S44, repeat step S43 until ei + △e ≥ e, then proceed to the next step; S45, the eccentricity of the tool is adjusted to e=(D-d2) / 2, and the second cutting part (2) is used to mill a hole to form a through hole with a diameter of D and coaxial with the prefabricated hole, thereby obtaining a finished hole to be machined, and the machining is completed.
8. The composite material hole making method according to claim 7, characterized in that: In the step S42, the radial single feed amount Δe is determined based on the material properties of the workpiece (100) and milling tests.
9. The composite material hole making method according to claim 1, characterized in that: The step S4 comprises the following steps: S41, the eccentricity of the tool is adjusted to e2=e1+(d1-d2) / 2, wherein d1 is the diameter of the first cutting portion (1) of the tool, and d2 is the diameter of the second cutting portion (2) of the tool; S42, calculating the tool eccentricity e=(D-d2) / 2 when machining the hole, and determining the radial feed speed f=(e-e2) / n, where n is the number of revolutions of the tool; S43, if e2+f*ni<e, then n(i+1)=ni+1, the tool eccentricity continues to increase at a uniform speed with the revolution of the tool, and the second cutting part (2) is used to continuously mill and form holes, wherein e2 is the tool eccentricity at the initial processing of the second cutting part (2), ni is the number of revolutions of the last tool revolution, n(i+1) is the number of revolutions of the current tool revolution, and i=1, 2, 3, 4...; S44, repeat step S43 until e2+f*ni≥e, then proceed to the next step; S45, the radial feeding of the tool stops, and the tool continues to rotate at least one revolution to obtain the hole to be machined.
10. The composite material hole making method according to claim 9, characterized in that: In step S42, the radial feed speed f is determined based on the material properties of the workpiece (100) and milling tests, and the number of revolutions n of the tool must be an integer.