Clamping tool for thin-wall curved-surface part and thin-wall curved-surface part machining method

Abstract

The embodiment of the invention discloses a clamping tool for a thin-wall curved-surface part and a thin-wall curved-surface part machining method, and relates to the technical field of machining, the clamping tool comprises a male die, a female die and an adjusting block, the adjusting block is arranged on the binding face of the male die, and the height of the adjusting block is adjustable, so that when a target part is wrapped between the binding face of the male die and the binding face of the female die, the target part is clamped between the binding face of the male die and the binding face of the female die. The end of the adjusting block makes contact with the first face of the target part. By designing the male die and the female die of which the binding surfaces are matched in shape, the part to be machined is wrapped in the inner cavity formed after the male die and the female die are buckled, and the binding surfaces of the male die and the female die are attached to the two surfaces of the part respectively; the gap between the part and the male die can be adjusted by adjusting the height of the adjusting block, the part can be clamped in an unstressed mode under the conditions that the thickness of the part is not uniform and deformation exists, clamping deformation of the part is reduced, and the machining precision of the part is improved.

Description

Technical Field

[0001] This application relates to the technical field of machining, and particularly relates to a clamping tooling for thin-walled curved surface parts and a machining method for thin-walled curved surface parts. Background Art

[0002] Parts blanks made of materials represented by ceramics, composite ceramics, and ceramic matrix composites are usually prepared by near-net shaping. If the parts are thin-walled curved surface parts, regardless of which process is used to prepare the blanks, there are usually certain errors in the blank thickness, and the surface errors are usually large. For parts made of hard and brittle materials used in fields such as aerospace, high requirements are usually placed on the part dimensions and geometric and dimensional tolerances. The directly formed blanks cannot meet the usage requirements and must be machined.

[0003] However, the near-net shaping process of hard and brittle material part blanks results in small machining allowances, and the blanks usually do not have high-precision reference surfaces. Using the conventional method of directly clamping the blank to the tooling with a pressing plate or screws will cause the blank to undergo a small deformation of dozens of micrometers under the clamping force. At this time, if the part surface is directly machined, after the clamping force is released, the part will have a springback deformation. When machining the next surface, the machining error caused by this small deformation will be further accumulated on the next surface, resulting in an increasing machining error of the part as the machining process progresses. Eventually, the thickness accuracy and surface accuracy of the machined part cannot be guaranteed, and high-precision machining cannot be achieved. Summary of the Invention

[0004] The main purpose of this application is to provide a clamping tooling for thin-walled curved surface parts and a machining method for thin-walled curved surface parts, aiming to solve the problem of low machining accuracy of thin-walled curved surface parts in the prior art.

[0005] To achieve the above purpose, the technical solutions adopted in the embodiments of this application are as follows:

[0006] In a first aspect, an embodiment of this application provides a clamping tooling for thin-walled curved surface parts, including: a male mold, a female mold, and an adjusting block, where:

[0007] The mating surfaces of the male mold and the female mold are in matching shapes, so that when the male mold and the female mold are buckled, the target part is wrapped in the inner cavity between the mating surfaces of the male mold and the female mold, and the mating surface of the male mold is in contact with the first surface of the target part, and the mating surface of the female mold is in contact with the second surface of the target part. The first surface of the target part is the machining reference surface to be processed;

[0008] The adjusting block is arranged on the mating surface of the male mold, and the height of the adjusting block is adjustable, so that when the target part is wrapped between the mating surfaces of the male mold and the female mold, the end of the adjusting block is in contact with the first surface of the target part.

[0009] In a possible implementation of the first aspect, a first threaded hole is formed on the fitting surface of the male mold, and the adjusting block is threadedly connected to the male mold through the first threaded hole.

[0010] In a possible implementation of the first aspect, the adjusting block includes a sleeve and a stud. The sleeve is threadedly connected to the male mold through the first threaded hole. The first threaded hole is a through hole, and the stud is arranged inside the sleeve and is threadedly connected to the sleeve.

[0011] In a possible implementation of the first aspect, a medium injection hole is formed on the female mold. The medium injection hole communicates with the inner cavity, and the medium injection hole is used to inject a filling medium into the inner cavity from the outside.

[0012] In a possible implementation of the first aspect, the clamping tooling further includes a plug pin. A medium outflow hole is formed on the female mold. The medium outflow hole communicates with the inner cavity, and the plug pin is in plug-in fit with the medium outflow hole.

[0013] In a possible implementation of the first aspect, the clamping tooling further includes a thin film. The thin film is arranged between the mating surface of the target part and the female mold to separate the female mold from the filling medium.

[0014] In a possible implementation of the first aspect, a second threaded hole is formed on the fitting surface of the female mold. The second threaded hole is used to be threadedly connected to a screw, and the end of the screw contacts the second surface of the target part.

[0015] In a possible implementation of the first aspect, the end of the adjusting block is spherical.

[0016] In a second aspect, an embodiment of the present application provides a processing method for a thin-walled curved surface part for a composite material bonding process, including the following steps:

[0017] Judge according to the envelope situation between the reconstructed three-dimensional digital model of the part blank and the three-dimensional digital model of the target part. When the target part can be processed, install the adjusting block of the clamping tooling for the thin-walled curved surface part provided in any one of the above first aspects on the male mold, and adjust the height of the adjusting block;

[0018] After the first surface of the part blank is fitted to the fitting surface of the male mold, fasten the female mold to the male mold so that the second surface of the part blank is fitted to the fitting surface of the female mold;

[0019] Inject a filling medium into the inner cavity between the fitting surfaces of the male mold and the female mold. After the filling medium is cured, separate the female mold and the part blank together from the male mold and turn them over for placement;

[0020] Fix the part blank on the female mold and machine the positioning surface of the first surface of the part blank;

[0021] Separate the part blank from the female mold, and machine other structural features of the part blank with the positioning surface as the reference.

[0022] In a possible implementation of the second aspect, after the first surface of the part blank is attached to the mating surface of the male mold, when the female mold and the male mold are buckled so that the second surface of the part blank is attached to the mating surface of the female mold, the method further includes:

[0023] Cover the second surface of the part blank with a thin film.

[0024] Compared with the prior art, the beneficial effects of the present application are:

[0025] A clamping tooling for thin-walled curved surface parts and a processing method for thin-walled curved surface parts provided by an embodiment of the present application wrap the part to be processed in the inner cavity after buckling by designing a male mold and a female mold with mating mating surface shapes, and the mating surfaces of the male mold and the female mold are respectively attached to the two surfaces of the part. Since the mating surface of the male mold located below is also provided with an adjusting block, the height of the adjusting block can be adjusted to adjust the gap between the part and the male mold, and the part can be clamped without stress in the case of uneven thickness and deformation of the part, reducing the clamping deformation of the part and improving the accuracy of the finally processed part. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of the clamping tooling for thin-walled curved surface parts provided by an embodiment of the present application;

[0027] Figure 2 is a schematic structural diagram of the male mold in the clamping tooling for thin-walled curved surface parts provided by an embodiment of the present application;

[0028] Figure 3 is a schematic structural diagram of the female mold in the clamping tooling for thin-walled curved surface parts provided by an embodiment of the present application;

[0029] Figure 4 is a schematic structural diagram of the part placed on the male mold in the clamping tooling for thin-walled curved surface parts provided by an embodiment of the present application;

[0030] Figure 5 is a schematic structural diagram of the part placed on the female mold in the clamping tooling for thin-walled curved surface parts provided by an embodiment of the present application;

[0031] Figure 6 is a schematic flow diagram of the processing method for thin-walled curved surface parts provided by an embodiment of the present application;

[0032] Figure 7 is a schematic diagram of the height error of the adjusting block in the processing method for thin-walled curved surface parts provided by an embodiment of the present application;

[0033] Figure 8 Schematic flow chart of the thin-walled curved surface part processing method provided by an embodiment of the present application in an implementation manner;

[0034] Markings in the figure: 1 - male mold, 2 - female mold, 21 - medium outflow hole, 22 - second threaded hole, 23 - medium injection hole, 3 - female mold and male mold pin, 4 - pin, 5 - adjusting block, 51 - theoretical position of the adjusting block, 52 - actual position of the adjusting block, 53 - height error of the adjusting block, 6 - blank part, 7 - thin film, 8 - tooling clamping screw, 9 - tooling clamping screw gasket, 10 - screw, 11 - screw gasket. Specific implementation manners

[0035] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0037] In the present application, unless otherwise clearly specified and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0038] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are for descriptive purposes only, and cannot be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" appearing throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes Scenario A, or Scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0039] Parts blanks are usually prepared by near-net shaping methods using materials represented by ceramics, composite ceramics, and ceramic matrix composites. If the part is a thin-walled curved surface part, regardless of the blank prepared by which process, the thickness of the blank usually has a certain error, and the profile error is usually large. For parts made of hard and brittle materials used in aerospace and other fields, usually higher requirements are placed on the part dimensions and geometric and dimensional tolerances. The blanks directly formed cannot meet the usage requirements and must be machined.

[0040] However, the near-net shaping process of hard and brittle material part blanks results in a small machining allowance, and the blanks usually do not have a high-precision reference surface. Using the conventional method of directly clamping the blank on the fixture with a pressing plate or screws will cause the blank to undergo a tiny deformation of dozens of micrometers under the clamping force. At this time, if the part profile is directly machined, after the clamping force is released, the part will have a springback deformation. When machining the next profile, the machining error caused by this tiny deformation will be further accumulated on the next profile, resulting in an increasing machining error of the part as the machining process progresses. Eventually, the accuracy of the thickness and the profile of the machined part cannot be guaranteed, and high-precision machining cannot be achieved.

[0041] For the invention application with the application number CN202110571734.5 and the title "A Flexible Tooling for Aircraft Skin Part Machining and Its Using Method", a flexible tooling is proposed, which includes a bottom plate, a base plate, buckles, flexible auxiliary components and foam cavities. The flexible auxiliary components and the foam cavities are respectively arranged between the bottom plate and the base plate. The flexible auxiliary components are used to support the skin part and limit its position. The foam cavity matches the edge contour of the skin part and encloses a cavity for pouring PCL plastic with the non-machined surface of the skin part. Through this flexible tooling and its using method, it can adapt to the shape of the skin part, effectively solve the problem of insufficient fitting degree between the flexible support and the part, and realize the stable support and fixation of the skin part with large elasticity. However, this solution only solves the problem of how to make the skin part fit perfectly with the tooling, and does not provide an effective method to adjust the blank pose, and cannot achieve high-precision machining of near-net-shaped hard and brittle material thin-walled curved surface parts.

[0042] Another example is the invention application with the application number CN201210306821.9 and the title "Auxiliary Tooling for High-Precision Thin Parts", which proposes to mill the end face of the non-working area of the thin-walled part into a chamfer, and clamp the thin-walled part in the auxiliary tooling. The clamping end of the auxiliary tooling is provided with a reverse chamfer that matches the chamfer on the thin-walled part, so as to realize high-precision grinding machining of easily deformable non-ferrous metal thin-walled parts. However, this method is applicable to non-ferrous metal parts with strong plasticity and requires necessary chamfers to be machined on the parts, and is not applicable to the machining of near-net-shaped hard and brittle material thin-walled curved surface parts.

[0043] The methods involved in the above solutions are all special processing methods for special structure parts. The part materials are usually materials with better plasticity, and the parts usually have rough references or positioning surfaces. For near-net-shaped hard and brittle material curved surface parts with both part thickness accuracy requirements and part surface accuracy requirements, the above methods cannot meet the high-precision machining requirements.

[0044] Therefore, the embodiments of the present application provide a clamping tooling for thin-walled curved surface parts, as shown in the attached Figure 1 - attached Figure 5 figure, including: a male mold 1, a female mold 2 and an adjusting block 5, wherein: the shapes of the mating surfaces of the male mold 1 and the female mold 2 match, so that when the male mold 1 and the female mold 2 are buckled, the target part is wrapped in the inner cavity between the mating surfaces of the male mold 1 and the female mold 2, and the mating surface of the male mold 1 fits with the first surface of the target part, and the mating surface of the female mold 2 fits with the second surface of the target part. The first surface of the target part is the to-be-machined reference surface; the adjusting block 5 is arranged on the mating surface of the male mold 1, and the height of the adjusting block 5 is adjustable, so that when the target part is wrapped between the mating surfaces of the male mold 1 and the female mold 2, the end of the adjusting block 5 contacts the first surface of the target part.

[0045] In this embodiment, the male mold 1 and the female mold 2 with matching mating surface shapes are designed to wrap the part to be machined in the inner cavity after they are buckled. Since the blank part needs to be machined to obtain the desired part, the target part described in this embodiment is the blank part 6 as shown in the appendix Figure 4 The mating surfaces of the male mold 1 and the female mold 2 are respectively attached to two sides of the part. Since the mating surface of the male mold 1 located below is also provided with an adjusting block 5, the height of the adjusting block 5 can be adjusted to adjust the gap between the part and the male mold 1. When the part has uneven thickness or deformation, the part can be clamped without stress, reducing the clamping deformation of the part and improving the accuracy of the finally machined part.

[0046] In one embodiment, an implementation method for adjusting the height of the adjusting block 5 is provided. A first threaded hole is opened on the mating surface of the male mold 1. The adjusting block 5 is threadedly connected to the male mold 1 through the first threaded hole. By rotating to adjust the depth of the threaded fit between the adjusting block 5 and the male mold 1, the adjustment of its height can be achieved. Further, for the convenience of adjustment, the adjusting block 5 is set in the form of a sleeve and a stud. The sleeve is threadedly connected to the male mold 1 through the first threaded hole. The first threaded hole is a through hole. The stud is arranged inside the sleeve and is threadedly connected to the sleeve. After the installation of the adjusting block 5 is completed as described above, the mating position of the stud and the sleeve can be adjusted from the back of the male mold 1 to achieve the adjustment of the height of the adjusting block 5.

[0047] In one embodiment, as shown in the appendix Figure 3 A medium injection hole 23 is opened on the female mold 2. The medium injection hole 23 is communicated with the inner cavity. The medium injection hole 23 is used to inject a filling medium into the inner cavity from the outside. The filling medium is used to eliminate the gap between the part and the female mold 2 caused by uneven part thickness and deformation amount. The requirements for the filling medium are that it is a fluid before injection, has a certain fluidity, solidifies after injection, has a certain supportability, and will not be crushed or broken during the part machining process. Low melting point metals or low melting point alloys can be selected. After the part is machined, the tooling can be heated to recover the filling medium for reuse. The medium injection holes 23 are arranged in an array, and the number can be adjusted according to the size of the tooling. A tool setting block is arranged at the upper end of the female mold 2 for tool setting before machining.

[0048] Further, the clamping tooling further includes a plug pin 4. A medium outflow hole 21 is opened on the female mold 2. The medium outflow hole 21 is communicated with the inner cavity. The plug pin 4 is in plug-in fit with the medium outflow hole 21. As described above, medium outflow holes 21 are opened at the mating surfaces of the female mold 2 and the male mold 1 in the front, back, left, and right four directions, and plug pins are provided. Through the cooperation of the plug pin 4 and the medium outflow hole 21, when the filling medium is injected from the medium injection hole 23, if it flows out from the medium outflow hole 21, it is blocked with the plug pin 4 to assist in judging the filling situation of the filling medium between the female mold 2 and the part.

[0049] In one embodiment, as shown in the attached Figure 5 figure, the clamping fixture further includes a thin film 7. The thin film 7 is disposed between the mating surface of the target part and the female mold 2 to separate the female mold 2 from the filling medium. The thin film 7 covers the side of the part facing the female mold 2 and is used to space apart the female mold 2 and the blank part from the filling medium, facilitating the demolding process in subsequent steps. The thickness of the thin film is generally 10 μm, and the maximum shall not be greater than 20 μm. A thin film with a temperature resistance higher than 120 °C is selected.

[0050] In one embodiment, as shown in the attached Figure 3 and the attached Figure 5 figure, a second threaded hole 22 is formed on the mating surface of the female mold. The second threaded hole 22 is used for threaded connection with the screw 10, and the end of the screw 10 contacts the second surface of the target part. After the blank is clamped, the female mold 2 also serves as a fixture for milling the blank. The shape of the mating surface of the female mold 2 and the blank is consistent with the shape of the theoretical digital model of the part. A second threaded hole 22 is provided around the mating surface of the female mold 2 and the blank. The second threaded hole 22 can be a stepped hole. The upper end of the hole is an avoidance hole for avoiding the drill bit when drilling the blank clamping hole after clamping is completed. The lower end of the hole is a threaded hole for clamping the blank in cooperation with the screw 10 before milling the profile surface, and a gasket 11 can be added during clamping to avoid damaging the part.

[0051] In one embodiment, the end of the adjusting block 5 can be set to be ball-shaped as shown in the attached Figure 2 figure. The adjusting block 5 supports the part and can also be set as a cuboid with a threaded hole in the middle, which is connected to the screw to achieve height adjustment. The size of the adjusting block 5 is generally 10 mm × 10 mm. If the curvature of the blank changes greatly and the structure of the blank is complex, the size of the adjusting block 5 can be appropriately reduced. If necessary, the shape of the end of the adjusting block 5 can also be changed to a ball shape, such as a spherical shape or a hemispherical shape, to reduce the contact area between the adjusting block 5 and the blank. The height of the adjusting block 5 can generally be set to 5 mm, and its axis is in the vertical direction. The number and arrangement position of the adjusting blocks 5 are determined by the shape and size of the blank. Usually, there are 4 adjusting blocks 5. If the size of the blank exceeds 300 mm × 300 mm, the number of adjusting blocks 5 is increased according to the actual situation. However, when calculating and adjusting the height of the adjusting blocks 5, the 4 adjusting blocks 5 are still adjusted. In addition, if there are special structures, such as large holes, cavities, etc., the adjusting blocks 5 are arranged at the necessary positions according to the actual situation.

[0052] Based on the same inventive concept as in the foregoing embodiments, as shown in the attached Figure 6 - the attached Figure 8 figure, an embodiment of the present application further provides a processing method for a thin-walled curved surface part. Using the clamping fixture for thin-walled curved surface parts provided by the embodiment of the present application, the method includes the following steps:

[0053] S10: Determine based on the enveloping situation between the reconstructed three-dimensional digital model of the part blank and the three-dimensional digital model of the target part. When the target part can be machined, install the adjusting block of the clamping tooling for thin-walled curved surface parts provided in the embodiments of the present application on the male mold, and adjust the height of the adjusting block.

[0054] S20: After fitting the first surface of the part blank with the fitting surface of the male mold, fasten the female mold to the male mold so that the second surface of the part blank is fitted with the fitting surface of the female mold.

[0055] S30: Inject a filling medium into the inner cavity between the fitting surfaces of the male mold and the female mold. After the filling medium solidifies, separate the female mold and the part blank together from the male mold, and place them in a flipped manner.

[0056] S40: Fix the part blank on the female mold and machine the positioning surface of the first surface of the part blank.

[0057] S50: Separate the part blank from the female mold and machine other structural features of the part blank with the positioning surface as the reference.

[0058] In this embodiment, the male mold 1 refers to the tooling element that fits with the reference surface to be machined of the blank. The male mold 1 is only used during the blank clamping process. The shape of the fitting surface between the male mold 1 and the reference surface to be machined of the blank is the same as the shape of the reference surface of the part's theoretical digital model, but there is an inward shrinkage of δ1 in the normal direction of the surface. δ1 = T + h + Δ1, where T is the theoretical maximum thickness of the blank, h is the thickness of the adjusting block 5, and Δ1 is the gap between the fitting surface of the adjusting block 5 and the male mold 1, generally 5 - 10 mm. A certain number of adjusting blocks 5 are arranged on the fitting surface of the male mold 1, and the back of the male mold 1 is simplified according to the current situation of the blank. Generally, it is sufficient to control the thickness of the male mold 1 to be greater than 20 mm.

[0059] The female mold 2 refers to the tooling element that is buckled on the blank during blank clamping and fits with the other side of the reference surface to be machined of the blank. The female mold 2 and the male mold 1 are fastened together to wrap the blank part. The female mold 2 also serves as the tooling for milling the blank after the blank clamping is completed. The shape of the fitting surface between the female mold 2 and the blank is the same as the shape of the part's theoretical digital model, but there is an inward shrinkage of δ2 in the normal direction of the surface. δ2 is generally set to 5 - 10 mm. After the male mold 1 and the female mold 2 are fastened together, the female mold 2 is fixed on the machine tool workbench by the cooperation of the tooling clamping screw 8 and the tooling clamping screw gasket 9, and the female mold 2 and the male mold 1 are positioned and connected by the female-male mold pin 3.

[0060] In the embodiment as shown in the appendix Figure 8 The present application is further described as follows:

[0061] First, analyze the state of the thin-walled curved surface part blank: measure the blank surface data through three-dimensional coordinate measurement or blue light scanning and other measurement methods. Reconstruct the three-dimensional digital model of the blank through the measurement results, and compare it with the three-dimensional digital model of the part to be processed to determine whether the blank can be processed into a part. If the blank deformation δP and thickness error δT have caused the blank to be unable to envelop the part geometry, it is determined that the blank cannot be processed into a part. If the part can be enveloped by the blank, the part can be processed.

[0062] Determination of key parameters of stress-free tooling: Key parameters of stress-free tooling include male die shrinkage δ1, adjustment block thickness, number of adjustment blocks, and female die shrinkage δ2. Other design parameters of clamping tooling and the design of other tooling are based on actual needs and general principles of tooling design.

[0063] Tooling processing: After completing the tooling design, mechanical processing is used to produce stress-free tooling and other tooling.

[0064] Blank posture adjustment: Place the real blank reconstruction digital model and the part theoretical digital model in the 3D software to the appropriate position, so that the real blank reconstruction digital model can completely envelop the part theoretical digital model, and the margin of each part is as uniform as possible. The point position of the adjustment block corresponding to the real blank reconstruction digital model is the basis for adjusting the adjustment block. Determine the blank measurement point according to the height of the adjustment block corresponding to the real blank reconstruction digital model, and compile a measurement program. Install the adjustment block on the male mold, turn the bolt to adjust the height, and use the micrometer to make the initial distance from the upper surface of each adjustment block to the male mold fitting surface is δ1-Δ1, and the error is controlled within ±0.005. Place the blank on the adjustment block, use the compiled measurement program to measure with the online measurement probe, determine the error of each adjustment block point, turn the adjustment block bolt to adjust the height according to the error size, and measure again after adjustment to ensure that the error measured at each adjustment block point is not greater than ±0.05. As shown in the attached Figure 7 As shown in the figure, the dotted line represents the theoretical digital model position of the part, the solid line represents the real blank reconstructed digital model position, the actual position 52 of the adjustment block is the adjustment block represented by the dotted line, the theoretical position 51 of the adjustment block is the adjustment block represented by the solid line, and the height error 53 of the adjustment block is the height difference between the same positions of the two. Figure 7 The point taken in the middle is the top point of the adjustment block.

[0065] Modulate the filling medium: The filling medium is prepared according to the actual needs of part processing. Usually the filling medium is a low melting point metal or low melting point alloy.

[0066] Pasting film and filling medium: that is, after pasting the first surface of the part blank with the pasting surface of the male mold, before buckling the female mold with the male mold to make the second surface of the part blank with the pasting surface of the female mold, the method also includes:

[0067] Cover the second side of the part blank with a film.

[0068] Cover the side of the blank part facing the female mold with the film 7, then place it on the adjusting block 5 of the male mold 1, then place the female mold 2 on the male mold 1, and use the tooling clamping screw 8 to fixedly clamp the male mold 1 and the female mold 2. Inject the prepared filling medium into the gap between the female mold 2 and the blank through the medium injection hole 23 of the female mold 2.

[0069] Let it stand for curing and demold: Let the filled tooling stand for a period of time. Generally, the filling medium is a low-melting-point metal or a low-melting-point alloy, and it can stand for 3 - 5 hours. After the filling medium is cured, remove the tooling clamping screw 8, separate the female mold 2 and the blank together from the male mold 1, and place it upside down.

[0070] Processing of the blank pressing holes: Clamp the blank on the female mold 2 with a pressing plate, and use a special drill bit that matches the processing characteristics of the material to process the pressing holes.

[0071] Processing of the blank positioning surface: Pass the blank clamping screw 10 through the blank pressing hole and tighten it on the second threaded hole 22 on the female mold 2 to realize the fixed clamping of the blank. Remove the pressing plate, use a special milling cutter that matches the processing characteristics of the material, and call the prepared numerical control program for processing the positioning surface to perform the processing of the positioning surface.

[0072] Processing of other structural features of the part: After the processing of the positioning surface is completed, disassemble the blank from the female mold 2, and use other tooling with the positioning surface as the reference to process other structural features of the part.

[0073] Taking the processing of an SiCf / SiC composite material part with the theoretical size of the blank part being 200mm×200mm×4mm as an example, the embodiments of the present application are further described:

[0074] First, scan the blank through blue light scanning technology and reconstruct the three-dimensional digital model of the blank. The maximum thickness of the blank is 4.23mm, the minimum thickness is 3.87mm, and the deformation amount of the blank is 0.24mm. By comparing the reconstructed digital model of the blank and the theoretical digital model of the part, it is determined that the blank can envelope the geometric shape of the part and the part can be processed.

[0075] Determine the key parameters of stress-free tooling, including the shrinkage of the male mold is 14.23mm, the thickness of the adjustment block is 5mm, the number of adjustment blocks is 4, and the shrinkage of the female mold is 5mm. The design of other design parameters of stress-free tooling and other tooling is based on actual needs and general principles of tooling design. After completing the tooling design, the stress-free tooling and other tooling are machined by mechanical processing. In the three-dimensional software, the real blank reconstruction digital model and the part theoretical digital model are placed in a reasonable position, so that the real blank reconstruction digital model can completely envelop the part theoretical digital model, and the margin of each part is as uniform as possible. Determine the blank measurement point according to the height of the adjustment block corresponding to the real blank reconstruction digital model, and compile a measurement program.

[0076] Install the adjustment block on the male mold, and turn the bolt to adjust the height. Use the micrometer to make the initial distance from the upper surface of each adjustment block to the male mold fitting surface 7.5mm, and the error is controlled within ±0.005. Place the blank on the adjustment block, use the prepared measurement program to measure with the online measurement probe, and determine that the height errors of the four adjustment block points are +0.172, -0.201, -0.148, and -0.339 respectively. Turn the adjustment block bolt according to the error size to adjust the height. After adjustment, measure again to ensure that the error measured at each adjustment block point is no more than ±0.05.

[0077] Select tin-bismuth alloy as the filling medium. Cover the front and back sides of the blank with a film for protection, then place it on the male mold adjustment block, then place the female mold buckle on the male mold, and use the tooling clamping screws to fix and clamp the male and female molds. Inject the prepared filling medium into the gap between the female mold and the blank through the female mold medium injection port. Let the filled tooling stand for 5 hours. After the filling medium solidifies, remove the tooling clamping screws, separate the female mold and the blank from the male mold, and flip them over.

[0078] Use a pressure plate to clamp the blank on the female mold, and use a special drill bit that matches the material processing characteristics to machine the clamping hole. Pass the blank clamping screw through the blank clamping hole and tighten it to the threaded hole on the female mold to achieve fixed clamping of the blank. Remove the pressure plate, use a special milling cutter that matches the material processing characteristics, call the compiled positioning surface processing CNC program, and perform positioning surface processing. After the positioning surface processing is completed, remove the blank from the female mold, and use the positioning surface as a reference to cooperate with other tooling to process other structural features of the part. The final processed part surface processing accuracy meets the surface accuracy requirement of ±0.075mm.

[0079] It should be noted that in this text, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or system. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or system including that element.

[0080] The serial numbers of the embodiments of the present application above are only for description and do not represent the superiority or inferiority of the embodiments.

[0081] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A clamping tool for thin-walled curved parts, characterized in that: include: Male mold, female mold and adjustment block, wherein: The shapes of the mating surfaces of the male mold and the female mold match each other, so that when the male mold and the female mold are buckled, the target part is wrapped in the inner cavity between the mating surfaces of the male mold and the female mold, and the mating surface of the male mold is mated with the first surface of the target part, and the mating surface of the female mold is mated with the second surface of the target part, and the first surface of the target part is the reference surface to be processed; The adjusting block is arranged on the fitting surface of the male mold, and the height of the adjusting block is adjustable so that when the target part is wrapped between the fitting surfaces of the male mold and the female mold, the end of the adjusting block contacts the first surface of the target part.

2. The clamping tool for thin-walled curved surface parts according to claim 1 is characterized in that: A first threaded hole is provided on the fitting surface of the male mold, and the adjusting block is threadedly connected to the male mold through the first threaded hole.

3. The clamping tool for thin-walled curved parts according to claim 2, characterized in that: The adjusting block comprises a sleeve and a stud, the sleeve is threadedly connected to the male mold through the first threaded hole, the first threaded hole is a through hole, and the stud is arranged in the sleeve and threadedly connected to the sleeve.

4. The clamping tool for thin-walled curved parts according to claim 1, characterized in that: The female mold is provided with a medium injection hole, the medium injection hole is communicated with the inner cavity, and the medium injection hole is used to inject a filling medium into the inner cavity from the outside.

5. The clamping tool for thin-walled curved surface parts according to claim 4 is characterized in that: The clamping tool also includes a latch, a medium outflow hole is provided on the female mold, the medium outflow hole is communicated with the inner cavity, and the latch is plugged and matched with the medium outflow hole.

6. The clamping tool for thin-walled curved surface parts according to claim 4, characterized in that: The clamping tool further comprises a film, which is arranged between the target part and the fitting surface of the female mold so as to separate the female mold from the filling medium.

7. The clamping tool for thin-walled curved surface parts according to claim 1, characterized in that: A second threaded hole is provided on the fitting surface of the female mold, and the second threaded hole is used for threaded connection with a screw, so that the end of the screw contacts the second surface of the target part.

8. The clamping tool for thin-walled curved surface parts according to claim 1, characterized in that: The end of the adjusting block is in a ball head shape.

9. A method for processing thin-walled curved surface parts, characterized in that: The following steps are involved: According to the envelope of the reconstructed three-dimensional digital model of the part blank and the three-dimensional digital model of the target part, it is judged that, if the target part can be processed, the adjusting block of the clamping tool for thin-walled curved surface parts according to any one of claims 1 to 8 is installed on the male mold, and the height of the adjusting block is adjusted; After the first surface of the part blank is fitted with the fitting surface of the male mold, the female mold is buckled with the male mold so that the second surface of the part blank is fitted with the fitting surface of the female mold; Injecting a filling medium into the inner cavity between the fitting surfaces of the male mold and the female mold, and after the filling medium solidifies, separating the female mold and the part blank from the male mold, and turning them over and placing them; Fixing the part blank on the female mold and processing the positioning surface of the first surface of the part blank; The part blank is separated from the female mold, and other structural feature processing is performed on the part blank based on the positioning surface.

10. The method for processing thin-walled curved surface parts for composite material bonding process according to claim 9, characterized in that: After the first surface of the part blank is bonded to the bonding surface of the male mold, before the female mold is buckled with the male mold so that the second surface of the part blank is bonded to the bonding surface of the female mold, the method further includes: The second surface of the part blank is covered with a film.

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