Low-damage and high-efficiency machining method for array composite pipe component

Abstract

The invention relates to a low-damage and high-efficiency machining method for an array composite material pipe component, and relates to the technical field of composite material honeycomb machining. According to the method, the machining process of the end face of the array composite pipe is simplified into the machining process of the single composite pipe along different offset distances; a rectangular coordinate system is established with the axis of the composite pipe as the original point, the composite pipe is fixed, the grinding wheel conducts linear feeding motion in the X direction, and the distance between the circle center of the grinding wheel and the circle center of the composite pipe in the Y direction is the offset distance; the maximum non-deformation amount of the grinding wheel cut-in stage under different offset distances after the maximum non-deformation cutting thickness changes continuously is calculated; firstly, the grinding wheel keeps a large offset ratio, and the cutting-in process of the array composite pipe component in the X positive direction is completed; and the grinding wheel is fed by a certain distance in the Y direction of the array composite pipe component and then does linear feeding motion in the X-negative direction of the array composite pipe component, and residual materials of the single pipe are removed till all the residual materials are removed. The method has the advantages of being good in universality, high in programmability and high in reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of composite honeycomb processing, and in particular to a low-damage and high-efficiency processing method for array composite tube components. Background Art

[0002] The array composite tube component is made of a number of composite tube cells glued together in a special arrangement on the horizontal plane. It is a new type of thin-walled porous honeycomb structure. The array composite tube has the advantages of low density, low thermal expansion coefficient, high axial stiffness, and excellent impact resistance. The array composite tube is usually glued and assembled with the composite skin to form a composite honeycomb sandwich component, and has been used in the aerospace field. Due to the limitations of the manufacturing process, the array composite tube still needs further machining after molding to obtain a complex surface shape to achieve assembly with the skin. At present, the use of electroplated diamond cup grinding wheels to remove the surface material of the array composite tube is the mainstream processing method, such as Figure 1 However, the anisotropy and heterogeneity of composite materials and the thin walls and discontinuity of honeycomb components pose a huge challenge to the surface processing quality of array composite tubes. In particular, during the machining of the end faces of array composite tubes, a large amount of tear damage is formed on the machined surface, and this tear damage is regularly formed in the machining area where the electroplated diamond cup grinding wheel cuts into the composite tube, such as Figure 2 As shown in Figure 2, a large amount of periodically distributed tearing damage seriously affects the overall performance of the component.

[0003] To address these technical challenges, the present invention proposes a composite tube grinding geometry model and a low-damage end-surface machining method for array composite tube components. This addresses the challenges of composite honeycomb machining, which lacks theoretical understanding and is difficult to control damage. Summary of the Invention

[0004] In response to the technical problems raised above, the present invention adopts a method for end face grinding of array composite tubes with a large offset ratio and variable feed speed based on the structural characteristics of the array composite tube and the undeformed chip thickness model during the grinding wheel cutting stage, specifically providing a low-damage and high-efficiency processing method for array composite tube components.

[0005] The technical means adopted in the present invention are as follows:

[0006] A low-damage, high-efficiency machining method for array composite tube components includes constructing a geometric model of the array composite tube grinding prior to machining, a simplified grinding wheel motion model considering the structural characteristics of the array composite tube, and a model of the undeformed chip thickness during the grinding wheel cutting phase, including the following steps:

[0007] S1. Simplify the end surface processing process of the array composite tube into the processing process of a single composite tube at different offset distances;

[0008] S2. Take the axis of the composite tube as the origin and establish the rectangular coordinate system Y W O W X W , the composite tube is fixed, the grinding wheel makes a linear feed motion along the X direction, and the distance between the center of the grinding wheel and the center of the composite tube along the Y direction is the offset distance δ;

[0009] S3. Based on the assumption of a single abrasive particle's circular motion trajectory, the thickness of the undeformed chip during the wheel's cutting phase is formed by the two consecutive abrasive particle trajectories. The distance between the two consecutive abrasive particles is L. cut , the grinding wheel linear speed is v s , the grinding wheel feed speed is v f , obtain the undeformed chip thickness Δx=v along the direction of the grinding wheel movement speed f (L cut / v s );

[0010] S4. Under different offset distances, the maximum undeformed chip thickness changes continuously. The maximum undeformed chip thickness during the grinding wheel cutting stage is Wherein, θ represents the angle between the line connecting the grinding wheel and the composite tube axis and the feed speed direction, and e is the axis distance in the cutting stage;

[0011] S5. Consider the axial distance e in the cutting stage as the initial axial distance when the grinding wheel is tangent to the pipe wall, that is, e = r s +r w +h, the ratio of the offset distance to the initial axis distance is defined as the offset ratio α, and the maximum undeformed chip thickness in the cutting stage is simplified to

[0012] Furthermore, the premise of S1 is to consider the characteristics that the cells of the array composite tube are uniformly arranged in the X direction and staggered and tangentially arranged in the Y direction.

[0013] Furthermore, the assumption of S3 is that the deformation of the tube wall under the action of grinding force is not considered.

[0014] Furthermore, the processing process includes the following steps:

[0015] S6. According to the established model, the grinding wheel first maintains a large offset ratio and a feed speed of v f1 , performing linear feed motion along the positive direction X of the array composite tube component to complete the cutting process of the composite tube;

[0016] S7. The grinding wheel is fed a certain distance along the Y direction of the array composite tube member. This distance needs to ensure that the grinding wheel and the composite tube are not in a tangent state or the theoretical tangent point is located in the processed area to ensure that the cutting stage is avoided during the processing;

[0017] S8, feed rate v f2Perform linear feed motion along the negative X direction of the array composite tube component to complete the removal of the remaining material of the single tube;

[0018] S9. Repeat steps S6, S7, and S8 to complete the processing of the end face of the array composite tube.

[0019] Furthermore, in S6, the initial offset ratio of the grinding wheel is greater than 0.5.

[0020] Furthermore, v f2 The value of v f1 At least 1.5 times of.

[0021] Furthermore, in step S9, the speed of the last cutting is v f3 , which meets 0.5v f3 ≥v f2 .

[0022] Compared with the existing technology, the present invention has the following advantages: the processing method of the present invention is not only suitable for the processing of the end faces and step surfaces of porous structures, but also has universal applicability to porous structures with different tubular cell sizes. The offset ratio can be used to quickly select the appropriate size of the grinding wheel for porous components with different tubular cell sizes; the method reduces the number of tearing damages caused by the array composite tube by rationally planning the tool trajectory; the use of a variable feed speed greatly improves the processing efficiency of the array composite tube component, and the relationship between the feed speeds in different processing stages is given; the method has the advantages of good universality, strong programmability, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 Schematic diagram of the processing process of the end face of the array composite tube

[0025] Figure 2 Schematic diagram of tear damage distribution on the surface of array composite tubes

[0026] Figure 3 Schematic diagram of the geometric model for composite tube processing

[0027] Figure 4 Schematic diagram of the undeformed chip thickness model during the cutting phase

[0028] Figure 5 Schematic diagram of the comparison of low-damage end surface processing methods for array composite tubes

[0029] Figure 6 Schematic diagram of the comparison of the processing morphology of the end face of the array composite tube

[0030] Figure 7 Statistical diagram of tear damage on the end face of the array composite tube

[0031] In the figure: 1. Grinding wheel, 2. Array composite tube component, 3. Composite tube. DETAILED DESCRIPTION

[0032] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0035] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0036] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0037] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0038] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0039] The embodiment of the present invention discloses a low-damage and high-efficiency processing method for array composite tube components;

[0040] Before machining, the geometric model of the array composite tube grinding is constructed. The simplified grinding wheel motion model and the undeformed chip thickness model during the grinding wheel cutting phase are considered, including the following steps:

[0041] like Figure 1 As shown, S1, considering the characteristics that the cells of the array composite tube 2 are evenly arranged in the X direction and staggered and tangentially arranged in the Y direction, the end surface processing process of the array composite tube is simplified to the processing process of a single composite tube 3 at different offset distances;

[0042] S2, such as Figure 3 As shown, the rectangular coordinate system Y is established with the axis of the composite tube as the origin. W O W XW , the composite tube is fixed, the grinding wheel 1 makes a linear feed motion along the X direction, and the distance between the center of the grinding wheel and the center of the composite tube along the Y direction is the offset distance δ;

[0043] S3, such as Figure 4 As shown, without considering the deformation of the tube wall under the action of the grinding force, based on the assumption of the circular motion trajectory of a single abrasive grain, the thickness of the undeformed chip during the cutting stage of the grinding wheel is formed by the two consecutive abrasive grain trajectories before and after, and the distance between the two consecutive abrasive grains before and after is recorded as L cut , the grinding wheel linear speed is v s , the grinding wheel feed speed is v f , the thickness of the undeformed chip along the direction of the grinding wheel speed is Δx = v f (L cut / v s );

[0044] S4. Under different offset distances, the maximum undeformed chip thickness changes continuously. Figure 4 The geometric relationship shown in the figure shows that the maximum deformation of the grinding wheel during the cutting stage is

[0045] S5. Due to the small thickness of the pipe wall, the axial distance e does not change much during the cutting stage. It can be regarded as the initial axial distance when the grinding wheel is tangent to the pipe wall, that is, e = r s +r w +h, the ratio of the offset distance to the initial axis distance is defined as the offset ratio α, and the maximum undeformed chip thickness in the cutting stage can be simplified as

[0046] The processing is carried out in the following steps:

[0047] S6. According to the model established in S5, when other machining parameters remain unchanged, increasing the offset ratio can reduce the maximum undeformed chip thickness in the cutting stage. Therefore, the grinding wheel can first maintain a large offset ratio (greater than 0.5) and a feed speed of v f1 , performing linear feed motion along the positive direction X of the array composite tube component to complete the cutting process of the composite tube;

[0048] S7, such as Figure 5 As shown in the method B, the grinding wheel is fed a certain distance along the Y direction of the array composite tube member. This distance needs to ensure that the grinding wheel and the composite tube are not in a tangent state or the theoretical tangent point is located in the processed area, so as to avoid the cutting stage during the processing;

[0049] S8, then make a linear feed motion along the negative direction of X of the array composite tube member at a feed speed to complete the removal of the remaining material of the single tube. In this embodiment, v f2 Usually v f1 twice as much;

[0050] S9, repeat the methods described in S6, S7, and S8 above to complete the processing of the end face of the array composite tube;

[0051] Example 1

[0052] The specific implementation steps for the establishment of composite pipes are as follows:

[0053] S1, such as Figure 3 As shown, the coordinate system Y is established with the axis of the composite tube as the coordinate origin. W O W X W , the inner diameter of the composite tube is r w , the thickness is h, the grinding wheel makes a linear feed motion along the X direction at a certain offset distance, and the radius of the grinding wheel is r s , axis O S The coordinates can be expressed as (x s ,-δ), let the axis distance in the cutting stage be e;

[0054] S2, such as Figure 4 As shown, the abrasive particle motion trajectory is simplified to a circular trajectory, and the distance between the two consecutive abrasive particles is L cut The maximum undeformed chip thickness formed by the two abrasive tracks is Δx = v f (L cut / v s ), the grinding wheel linear speed is v s , the grinding wheel feed speed is v f ,;

[0055] S3. According to the geometric relationship, the maximum undeformed chip thickness in the actual cutting stage can be expressed as the distance between C and E. Since Δx is much smaller than the grinding wheel radius r s , then |CD| is approximately equal to Δx, and according to the geometric relationship, we can get |CE|=|CD|cosθ;

[0056] S4, where cosθ can be expressed as Since the thickness of the pipe wall is small, the axis distance e does not change much during the cutting stage. It can be regarded as the initial axis distance when the grinding wheel is tangent to the pipe wall, that is, e = r s +r w +h, unify the grinding wheel size and the composite tube size, and define the ratio of the offset distance to the initial axis distance as the offset ratio α;

[0057] S5, the maximum undeformed chip thickness during the cutting phase can be simplified as Under the condition of certain abrasive grain size, the maximum undeformed chip thickness in the cutting stage is affected by feed rate, grinding speed and offset ratio;

[0058] The specific implementation steps of the low-damage end surface processing method of the array composite tube component are as follows:

[0059] S6, such as Figure 5 As shown in the figure, considering the characteristics of uniform arrangement of composite tubes in the X direction and staggered tangential arrangement in the Y direction, two methods for processing the end faces of array composite tubes are described;

[0060] As a comparative example, S7, Figure 5 As shown in the described method A, the grinding wheel performs a reciprocating linear feed motion along the X direction of the array composite tube at a low feed speed vf1 when the offset ratio is 0;

[0061] S8, the spacing between tool paths is the distance between the centers of the upper and lower adjacent tubes along the Y direction Each pass can complete the cutting of a row of composite tubes, ensuring high processing efficiency;

[0062] S9, such as Figure 5 As shown in the described method B, the grinding wheel first performs a linear feed motion along the positive X direction of the array composite tube at a high feed speed vf2 with an offset ratio greater than 0.5 to achieve the cutting process of the composite tube. The large offset ratio can reduce the thickness of the undeformed chip during the cutting stage and inhibit tearing damage.

[0063] S10. Then, the grinding wheel is fed a certain distance in the Y direction and linearly fed in the opposite X direction at a higher feed speed vf3, gradually completing the removal of the residual material of the composite tube. It is worth noting that in this path, it is necessary to ensure that the tangent point between the grinding wheel and the composite tube is located in the processed area, or to express it in other words, to ensure that the grinding wheel and the composite tube are not in a tangent state, so as to avoid the occurrence of a secondary cutting process;

[0064] S11, then repeat steps S9 and S10 to grind the next row of composite tubes. In the last pass, since the grinding wheel will not cut into the adjacent tubes, the last pass still uses a higher feed speed vf3.

[0065] S13, the relationship between the above feed speed is 1.5v f1 ≤v f2 ≤0.5v f3 ;

[0066] S14, such as Figure 6 As shown in the figure, by comparing the machining morphologies of the array composite tube end face obtained by the two machining methods, the machining surface quality of the array composite tube end face machining method using a large offset ratio and a variable feed speed is higher.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-damage and high-efficiency processing method for array composite tube components, characterized in that: Before machining, the geometric model of the array composite tube grinding is constructed. The simplified grinding wheel motion model and the undeformed chip thickness model during the grinding wheel cutting phase are considered, including the following steps: S1. Simplify the end surface processing process of the array composite tube into the processing process of a single composite tube at different offset distances; S2. Take the axis of the composite tube as the origin and establish the rectangular coordinate system Y W O W X W , the composite tube is fixed, the grinding wheel makes a linear feed motion along the X direction, and the distance between the center of the grinding wheel and the center of the composite tube along the Y direction is the offset distance δ; S3. Based on the assumption of a single abrasive particle's circular motion trajectory, the thickness of the undeformed chip during the wheel's cutting phase is formed by the two consecutive abrasive particle trajectories. The distance between the two consecutive abrasive particles is L. cut , the grinding wheel linear speed is v s , the grinding wheel feed speed is v f , obtain the undeformed chip thickness Δx=v along the direction of the grinding wheel movement speed f (L cut / v s ); S4. Under different offset distances, the maximum undeformed chip thickness changes continuously. The maximum undeformed chip thickness h m for: Wherein, θ represents the angle between the line connecting the grinding wheel and the composite tube axis and the feed speed direction, and e is the axis distance in the cutting stage; S5. Consider the axial distance e in the cutting stage as the initial axial distance when the grinding wheel is tangent to the pipe wall, e = r s +r w +h, the ratio of the offset distance to the initial axis distance is defined as the offset ratio α, and the maximum undeformed chip thickness in the cutting stage is simplified to 2. The method according to claim 1, characterized in that The premise of S1 is to consider the characteristics that the cells of the array composite tube are evenly arranged in the X direction and staggered and tangentially arranged in the Y direction.

3. The method according to claim 1, characterized in that The assumption of S3 is that the deformation of the tube wall under the action of grinding force is not considered.

4. A method according to any one of claims 1 to 3, characterized in that: The processing process includes the following steps: S6. According to the established model, the grinding wheel first maintains a large offset ratio and a feed speed of v f1 , performing linear feed motion along the positive direction X of the array composite tube component to complete the cutting process of the composite tube; S7. The grinding wheel is fed a certain distance along the Y direction of the array composite tube member. This distance needs to ensure that the grinding wheel and the composite tube are not in a tangent state or the theoretical tangent point is located in the processed area to ensure that the cutting stage is avoided during the processing; S8, feed rate v f2 Perform linear feed motion along the negative X direction of the array composite tube component to complete the removal of the remaining material of the single tube; S9. Repeat steps S6, S7, and S8 to complete the processing of the end face of the array composite tube.

5. The method according to claim 4, wherein in S6, the initial offset ratio of the grinding wheel is greater than 0.

5.

6. The method according to claim 4, wherein f2 The value of v f1 At least 1.5 times of.

7. According to the method of claim 4, in step S9, the speed of the last cutting is v f3 , which meets 0.5v f3 ≥v f2 .

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