Vacuum spot test system and method for large composite material workpiece

Abstract

The invention relates to a vacuum spot test system and method for a large composite material workpiece, belongs to the technical field of autoclave vacuum detection, and solves the problems of high difficulty in vacuumizing and vacuum measurement and poor precision of a large irregular workpiece in the prior art. The system comprises a plurality of mobile vacuum spot test devices and a control center. The control center partitions the large composite material workpiece and arranges spot test points according to the structure and material characteristics of the large composite material workpiece, issues tasks to the mobile vacuum spot test device, controls the mobile vacuum spot test device to move to a target position and completes vacuumizing and vacuum measurement operation of the corresponding spot test points. According to the invention, a plurality of mobile vacuum spot test devices are adopted to carry out vacuumizing and vacuum measurement operations on a plurality of spot test points of the large workpiece at the same time, and the workpiece is partitioned and the spot test points are arranged according to the characteristics of the workpiece, so that vacuumizing and vacuum measurement of each local area of the large irregular workpiece can be carried out synchronously, and the spot test precision is improved.

Description

Technical Field

[0001] The invention relates to the technical field of autoclave vacuum detection, and in particular to a vacuum extraction detection system and method for a large composite material workpiece. Background Art

[0002] Before the workpiece is sent to the autoclave for hot pressing, it must first be placed in the mold and encapsulated with vacuum belts, sealing strips, vacuum pumps, etc. During the encapsulation process, it is necessary to ensure that the vacuum bag and the mold are tightly bonded to avoid air leakage. After the encapsulation is completed, the air in the bag is extracted using a vacuum pump to achieve the required vacuum level. This process helps to remove volatiles and bubbles in the prepreg and improve the quality and performance of the product. After the vacuuming is completed, the encapsulated workpiece (i.e. the combination of prepreg and mold) is sent to the autoclave. Vacuuming can remove air and volatiles from the prepreg, reduce porosity, and improve the density and performance of the product.

[0003] During the vacuuming process, pay close attention to the changes in the vacuum gauge or vacuum display to ensure that the vacuum degree reaches the predetermined requirements. For large workpieces, the vacuuming time should be kept for more than 15 minutes to ensure sufficient exhaust. After the vacuuming is completed, turn off the vacuum system and perform a leak test, check the vacuum gauge or vacuum display, and ensure that the vacuum gauge pressure reaches -0.1MPa within 15 minutes and remains unchanged.

[0004] However, for large irregularly shaped workpieces, different positions may have different vacuum requirements due to different shapes, structures, materials and process requirements. Therefore, it is difficult for the conventional vacuuming and vacuum measuring devices to accurately perform vacuuming and vacuum measuring operations. Summary of the invention

[0005] In view of the above analysis, the present invention aims to provide a vacuum extraction and measurement system and method for large composite workpieces, so as to solve the problems of difficulty and poor precision in vacuum extraction and measurement of large irregular workpieces in the prior art.

[0006] On the one hand, the present invention provides a vacuum testing system for large composite workpieces, characterized in that it includes a control center and multiple mobile vacuum testing devices; the control center divides the large composite workpiece into zones and arranges testing points according to the structure and material characteristics of the large composite workpiece, and controls the mobile vacuum testing devices to move to the target position and complete the vacuuming and vacuum measuring operations of the corresponding testing points.

[0007] Furthermore, the mobile vacuum extraction testing device includes a mobile vehicle and a control module and a vacuum module arranged on the mobile vehicle.

[0008] Furthermore, the control module is used to communicate with the control center, control the movement of the mobile vehicle and control the operation of the vacuum module.

[0009] Furthermore, the control module includes a PLC controller and a vacuum sensor.

[0010] Furthermore, the vacuum module includes a vacuum pump, a check valve, a vacuum tank, a vacuum regulating valve, a vacuum hose and a vacuum joint connected in sequence, and the vacuum joint is connected to the first interface of the sampling point of the large composite workpiece; and also includes a vacuum measuring joint, which is connected to the second interface of the sampling point of the large composite workpiece.

[0011] In another aspect, the present invention provides a vacuum extraction method for a large composite workpiece, using the vacuum extraction system for a large composite workpiece as described above.

[0012] Further, the following steps are included:

[0013] S1: Establishing a three-dimensional model of the large composite workpiece, dividing the area, and arranging sampling points;

[0014] S2: The control center matches the mobile vacuum testing device to the area divided in step S1; and issues tasks to the corresponding mobile vacuum testing device according to the matching result;

[0015] S3: The mobile vacuum testing device that receives the task automatically moves to the target position, and the vacuum extraction joints and vacuum testing joints in the mobile vacuum testing device are connected to the testing points of the large composite material workpiece in a one-to-one correspondence;

[0016] S4: the mobile vacuum extraction and testing device starts automatic vacuum extraction and vacuum degree detection operations according to the working parameters in the task;

[0017] S5: Determine whether the large composite material workpiece meets the standards and provide feedback on the results.

[0018] Furthermore, step S1 specifically includes S11: establishing a three-dimensional model for the large composite material workpiece specifically includes establishing a three-dimensional structural model of the workpiece, recording vacuum requirements at different positions, the material of each part and the gas permeability of the corresponding material.

[0019] Furthermore, the vacuum degree requirement includes an initial vacuum degree value, a delay time, a test time, and a test critical value.

[0020] Furthermore, the area division in step S1 is divided into three steps: S121: according to the three-dimensional structure model of the workpiece and in combination with the vacuum degree requirements at different positions, the surface area of ​​the workpiece is divided into unit cells using the finite element method;

[0021] S122: classify all cells according to the surface characteristics of each cell;

[0022] S123: Perform secondary classification on each cell according to the gas permeability of the material.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0024] (1) The present invention divides the workpiece into zones and arranges sampling points according to the characteristics of the workpiece itself through a control center, and controls multiple mobile vacuum sampling devices to simultaneously perform vacuum extraction and vacuum measurement operations on multiple sampling points of a large workpiece. At the same time, the vacuum extraction rate, initial vacuum degree, improved sampling accuracy and test critical value of each mobile vacuum sampling device can be set separately, so that the vacuum extraction and vacuum measurement of each local area of ​​a large irregular workpiece can be carried out synchronously, the sampling efficiency is high, and the sampling accuracy is improved.

[0025] (2) The mobile vacuum testing device of the present invention can be moved at will, and the control center can match it according to the vacuum degree requirements. The mobile vacuum testing device can be quickly moved to the target position for testing, saving time.

[0026] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0028] Figure 1 It is a structural schematic diagram of a mobile vacuum extraction and testing device in Example 1 of the present invention;

[0029] Figure 2 It is a flow chart of the vacuum extraction method of a large composite material workpiece in Example 2 of the present invention;

[0030] Figure 3 Schematic diagram of the vacuum extraction method for a large composite material workpiece in Example 2 of the present invention.

[0031] Reference numerals:

[0032] 1-vacuum pump; 2-vacuum tank; 3-check valve; 4-vacuum regulating valve; 5-vacuum sensor; 6-vacuum measuring joint; 7-vacuum extraction joint; 8-PLC controller; 9-touch screen; 10-power supply; 11-mobile vehicle; 12-mobile vacuum extraction and testing device; 100-workpiece. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0034] Example 1

[0035] The present invention provides a vacuum pumping system for large composite material workpieces, comprising a plurality of mobile vacuum pumping devices 12 and a control center for controlling the plurality of mobile vacuum pumping devices 12, for performing vacuum pumping treatment on large composite material workpieces to be sent into an autoclave for a hot pressing process, and detecting the treated workpieces to ensure that they meet the requirements of the hot pressing process for the vacuum degree of the workpiece.

[0036] The large composite material workpiece involved in the present invention refers to a composite material workpiece having at least two regions with different vacuum requirements in design requirements and used for hot pressing molding.

[0037] like Figure 1 As shown, the mobile vacuum extraction device 12 includes a mobile vehicle 11, a control module and a vacuum module. The mobile vehicle 11 includes a carriage and wheels, and the carriage is used to set the control module and the vacuum module. The wheels are located at the bottom of the carriage to facilitate the overall movement of the device.

[0038] The control module includes a PLC controller 8, a vacuum sensor 5, a touch screen 9 and a control cable, which are used to control the vacuum module.

[0039] The vacuum module includes a vacuum pump 1, a check valve 3, a vacuum tank 2, a vacuum regulating valve 4, a vacuum hose, a vacuum joint 7, and a vacuum measuring joint 6, which are connected in sequence. The vacuum pump 1 is installed and fixed on the mobile vehicle 11. The vacuum pump 1 is connected to the check valve 3 through a metal pipe, and the check valve 3 is connected to the vacuum tank 2 through a metal pipe. The pipeline leading out from the vacuum tank 2 can be divided into multiple branches, and a vacuum regulating valve 4 is installed on each branch. The vacuum regulating valve 4 is connected to the vacuum joint 7 through a metal pipe, and the vacuum joint 7 is connected to the workpiece. When the vacuum pump 1 is started, the vacuum regulating valve 4 is opened and the workpiece is vacuumed. At the same time, multiple groups of vacuum sensors 5, valves and vacuum measuring joints 6 are arranged in a matching manner. One end of the vacuum sensor 5 is connected to the vacuum measuring joint 6 through a metal pipe; the other end is connected to the PLC controller 8 through a metal pipe.

[0040] The vacuum sensor 5 is connected to the workpiece through a valve (not shown in the figure) and a vacuum measuring joint 6, and the opening of the valve is controlled by a touch screen 9 and a PLC controller 8 to measure the vacuum degree of the workpiece. The vacuum sensor 5 transmits a signal to the PLC controller 8, and the PLC controller 8 feeds back the data to the control center, which stores the data and can display it on a display screen.

[0041] The vacuum joint 7 and the vacuum measuring joint 6 are connected to the workpiece respectively. The workpiece can be vacuumed by starting the vacuum pump 1. The vacuum regulating valve 4 is used to adjust the vacuum degree.

[0042] The PLC controller 8 is connected to the vacuum regulating valve 4 and is also connected to the touch screen 9 , and the opening and closing of the vacuum regulating valve 4 can be controlled by the touch screen 9 .

[0043] The vacuum measuring joint 6 is connected to the workpiece. When the workpiece is evacuated, the vacuum sensor 5 detects the vacuum value of the workpiece and transmits the data to the PLC controller 8. The PLC controller 8 transmits the data to the touch screen 9. The touch screen 9 can display the data. At the same time, operation buttons are set on the touch screen 9. The vacuum pump 1, the check valve 3, and the vacuum regulating valve 4 can be controlled to open and close through the PLC controller 8, and finally the whole system can realize the function of evacuating and measuring the vacuum of the workpiece.

[0044] The power supply 10 is installed on the mobile vehicle 11 to supply power to the entire system. The power supply 10 can also be supplied by a nearby fixed power supply via a cable.

[0045] The mobile vehicle 11 can be moved to any position at will to perform vacuum testing on workpieces that need to be vacuum tested.

[0046] The control center is connected to the PLC controller 8 of each mobile vacuum pumping and testing device 12 by electrical signals, preferably by wireless signals. The control center can control each mobile vacuum pumping and testing device 12 to move to a desired position, and control multiple mobile vacuum pumping and testing devices 12 to perform vacuum pumping and vacuum degree detection operations on different positions of the workpiece simultaneously or in a certain order.

[0047] Compared with the prior art, the vacuum extraction and measurement system for large composite workpieces provided in this embodiment can simultaneously perform vacuum extraction and vacuum measurement operations on multiple parts of a large composite workpiece, solving the problem that conventional vacuum extraction and vacuum measurement devices are difficult to accurately vacuum extraction and vacuum measurement of large workpieces, thereby improving production efficiency.

[0048] Example 2

[0049] Embodiment 2 of the present invention, as Figure 2-Figure 3As shown, a vacuum extraction method for a large composite workpiece is disclosed, which is implemented using a vacuum extraction system for a large composite workpiece of Example 1. This method is used to evacuate and measure the vacuum degree of a large composite workpiece before hot pressing.

[0050] The vacuum testing method of this embodiment 2 specifically includes the following steps:

[0051] S1: Establishing a three-dimensional model of the large composite workpiece, dividing the area, and arranging sampling points;

[0052] S2: The control center matches the mobile vacuum testing device 12 to the area divided in step S1; and according to the matching result, issues the task to the corresponding mobile vacuum testing device 12;

[0053] S3: The mobile vacuum testing device 12 that receives the task automatically moves to the target position, and the vacuum extraction joint 7 and the vacuum testing joint 6 in the mobile vacuum testing device 12 are connected to the testing points of the large composite material workpiece in a one-to-one correspondence;

[0054] S4: The mobile vacuum testing device 12 starts to automatically evacuate and detect the vacuum degree according to the parameters in the task;

[0055] S5: Determine whether the large composite material workpiece meets the standards and provide feedback on the results.

[0056] According to the vacuum extraction method of this embodiment, different areas can be vacuumed at different speeds according to the characteristics of the large composite workpiece itself, and the vacuum degrees in different areas can be different to meet the needs of hot pressing of large composite workpieces.

[0057] Specifically, step S1 specifically includes S11: establishing a three-dimensional model of the large composite material workpiece, including establishing a three-dimensional structural model of the workpiece, and recording the vacuum requirements at different positions, the material of each part, and the gas permeability of the corresponding material. The vacuum requirements include: initial vacuum value, delay time, test time, and test critical value.

[0058] Step S1 also includes S12: dividing the area, which is specifically divided into three steps: S121: According to the three-dimensional structural model of the workpiece and the vacuum requirements at different positions, the finite element method is used to divide the surface area of ​​the workpiece into cells. The principle is to divide areas with different vacuum requirements into different cells.

[0059] S122: Classify all cells according to the surface features of each cell, which can be divided into plane areas, convex areas, complex curved surfaces and / or concave areas, edge and corner areas, wherein the convex area refers to a large area of ​​surface protruding outward, the complex curved surface area refers to an area including at least one convex part and one concave part, and the concave area refers to a large area of ​​inward concave area. The classification of different workpieces is different, and may include only two types of areas, or may include multiple types of areas.

[0060] S123: For each cell, secondary classification is performed according to the gas permeability of the material corresponding to the cell, and a preset permeability range is used as a reference standard to divide all areas into high permeability areas (areas with permeability higher than the preset range), low permeability areas (areas with permeability lower than the preset range) and medium permeability areas (areas with permeability within the preset range).

[0061] Step S1 also includes S13: arranging sampling points, specifically: preliminarily setting a sampling point for each cell, wherein one sampling point includes a first interface connected to the vacuum joint 7 and a second interface connected to the vacuum joint 6.

[0062] On this basis, the number of sampling points in each cell is adjusted according to the classification in steps S122 and S123.

[0063] Specifically, if the cell is a convex area, one sampling point is reduced to be set for two adjacent cells; if the cell is an edge and corner area, a complex curved surface and / or a concave area, three sampling points are increased to be set for two adjacent cells.

[0064] Furthermore, if the cell is a high permeability area, based on the previous step, the number of interface groups for each cell is increased by a certain proportion, for example, from three sampling points set for two adjacent cells to four sampling points set for two adjacent cells; if the cell is a low permeability area, based on the previous step, the number of sampling points for each cell is reduced by a certain proportion, for example, from one sampling point set for one cell to one sampling point set for two adjacent cells. If the cell is a medium permeability area, the sampling points remain unchanged.

[0065] The maximum density of sampling point setting is two groups for one cell, and the minimum density is one group for four adjacent cells.

[0066] In step S2, the sampling points are classified according to the vacuum requirements of the areas where the sampling points are located, and the sampling points in the areas with the same vacuum requirements are of the same category. The adjacent sampling points of the same category match the same mobile vacuum sampling device 12, and the number of interface groups that can be matched by each mobile vacuum sampling device 12 is consistent with the number of vacuum extraction joints 7 and vacuum measurement joints 6 it has.

[0067] The control center obtains the matching method between the mobile vacuum testing device 12 and the testing point through calculation optimization, determines the working parameters and target position of each mobile vacuum testing device 12 according to the matching relationship, and publishes the working parameters and target position as task information to the mobile vacuum testing device 12.

[0068] The task in step S2 specifically includes working parameters and target positions, wherein the working parameters include initial vacuum values, delay time, test time and test critical values ​​of corresponding sampling points; the target position is a position adjacent to the corresponding sampling point and convenient for operation.

[0069] In step S3, the mobile vacuum extraction and testing device 12 moves to the target position according to the information in the task, and then connects the vacuum extraction joint 7 and the vacuum testing joint 6 to the first interface and the second interface of the extraction and testing point of the large composite material workpiece matched in step S2 in a one-to-one correspondence. This operation can be performed manually by an operator or automatically by a mechanical arm or a robot.

[0070] In step S4, the process of automatically evacuating the vacuum and detecting the vacuum degree is specifically as follows:

[0071] S41: Start the vacuum pump 1, open the vacuum regulating valve 4, and start to evacuate; at the same time, open the valve connected to the vacuum measuring joint 6, and detect the vacuum degree through the vacuum sensor 5;

[0072] S42: Determine whether the vacuum degree reaches the value of the initial vacuum degree δ in the working parameters of the task issued by the control center. If so, close the corresponding vacuum regulating valve 4.

[0073] In step S41, the control center can adjust the vacuuming rates of different sampling points according to the real-time data, so that all the sampling points can complete the vacuuming at the same time.

[0074] Step S5 specifically includes: S51: after all vacuum regulating valves 4 are closed, start timing;

[0075] S52: After the timing reaches the delay time T1, the vacuum degree is measured again, and the test duration is T2;

[0076] S53: Obtain the data fed back by the vacuum sensor 5 to determine whether the vacuum degree at this time reaches the corresponding test critical value σ. If the data fed back by all the vacuum sensors 5 reach the corresponding test critical value σ, the workpiece is determined to be qualified; otherwise, the workpiece is determined to be unqualified.

[0077] The present embodiment is further described below with reference to specific cases.

[0078] See also Figure 3 For a large workpiece 100 with irregular contours, different areas have different requirements for vacuum, and different areas have different initial vacuum values. After reaching the initial vacuum value, after a certain period of time, the vacuum value decreases to a certain value, and the vacuum requirements of different areas after the decrease are also different. Only when all values ​​meet the requirements, the vacuum test of the workpiece meets the requirements.

[0079] According to step S1, the modeling, area division and sampling point setting of the workpiece 100 are as follows: Figure 3 As shown (for simplicity, only the plane model is shown). The red lines show the area division, and each black line extending from the mobile vacuum extraction and testing device 12 to the workpiece 100 represents a vacuum extraction pipeline and a vacuum testing pipeline, and the end of the black line corresponds to a extraction and testing point.

[0080] In step S2, the sampling points of the same vacuum degree monitoring standard are classified into one category, such as Figure 3 , divided into three categories: A, B, and C. The working parameters that need to be met by these three types of sampling points are shown in Table 1.

[0081] Table 1

[0082]

[0083]

[0084] Correspondingly, the plurality of mobile vacuum testing devices 12 are divided into three groups, which are matched with the three types of testing points A, B and C respectively, and the positions and working parameters of the corresponding testing points are published to each mobile vacuum testing device 12 .

[0085] The parameters of the mobile vacuum extraction test device 12 of group A include initial vacuum degree δ1 = -0.098 MPa, delay time T1 = 60 s, test time T2 = 1800 s, and test critical value σ1 = -0.096 MPa;

[0086] The parameters of the mobile vacuum extraction test device 12 of group B include initial vacuum degree δ2 = -0.095 MPa, delay time T1 = 60 s, test duration T2 = 1800 s, and test critical value σ2 = -0.093 MPa;

[0087] The parameters of the mobile vacuum extraction testing device 12 of group C include initial vacuum degree δ3 = -0.093 MPa, delay time T1 = 60 s, test time T2 = 1800 s, and test critical value σ3 = -0.090 MPa.

[0088] In step S3, each mobile vacuum testing device 12 that receives the task moves to the corresponding testing point position, and then connects the vacuum joint 7 and the vacuum testing joint 6 to the interface of the large composite material workpiece matched in step S2 in a one-to-one correspondence, such as Figure 3 shown.

[0089] Then, step S4 is executed, and all the test points start to evacuate at the same time. When the vacuum degree of all feedbacks reaches or exceeds the initial vacuum degree, step S5 is executed. After the delay time T1, the whole system enters the vacuum measurement stage at the same time. After the test time T2, the test time value is reached, and the vacuum degree obtained by the test is judged. If the vacuum degree of any test point is lower than the corresponding test critical value, the test workpiece fails; if the vacuum degree of all test points is higher than the test critical value, the test workpiece is qualified.

[0090] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A vacuum extraction system for large composite material workpieces, characterized in that: It includes a control center and multiple mobile vacuum extraction and testing devices; The control center divides the large composite material workpiece into zones and arranges sampling points according to the structure and material characteristics of the large composite material workpiece, and controls the mobile vacuum sampling device to move to the target position and complete the vacuum extraction and vacuum measurement operations of the corresponding sampling points.

2. The vacuum extraction testing system for large composite material workpieces according to claim 1, characterized in that: The mobile vacuum extraction and testing device comprises a mobile vehicle and a control module and a vacuum module arranged on the mobile vehicle.

3. The vacuum extraction testing system for large composite material workpieces according to claim 2, characterized in that: The control module is used to communicate with the control center, control the movement of the mobile vehicle and control the operation of the vacuum module.

4. The vacuum extraction testing system for large composite material workpieces according to claim 3, characterized in that: The control module includes a PLC controller and a vacuum sensor.

5. The vacuum extraction testing system for large composite material workpieces according to claim 4, characterized in that: The vacuum module includes a vacuum pump, a check valve, a vacuum tank, a vacuum regulating valve, a vacuum hose and a vacuum joint connected in sequence, wherein the vacuum joint is connected to a first interface of a sampling point of the large composite workpiece; and also includes a vacuum measuring joint, which is connected to a second interface of the sampling point of the large composite workpiece.

6. A vacuum extraction method for a large composite material workpiece, characterized in that: A vacuum extraction system for a large composite material workpiece according to any one of claims 1-5.

7. The vacuum extraction method for a large composite material workpiece according to claim 6, characterized in that: The steps include: S1: Establishing a three-dimensional model of the large composite workpiece, dividing the area, and arranging sampling points; S2: The control center matches the mobile vacuum extraction and testing device to the area divided in step S1; And according to the matching results, the task is issued to the corresponding mobile vacuum extraction and testing device; S3: The mobile vacuum testing device that receives the task automatically moves to the target position, and the vacuum extraction joints and vacuum testing joints in the mobile vacuum testing device are connected to the testing points of the large composite material workpiece in a one-to-one correspondence; S4: the mobile vacuum extraction and testing device starts automatic vacuum extraction and vacuum degree detection operations according to the working parameters in the task; S5: Determine whether the large composite material workpiece meets the standards and provide feedback on the results.

8. The vacuum extraction method for a large composite material workpiece according to claim 7, characterized in that: Step S1 specifically includes S11: establishing a three-dimensional model for the large composite material workpiece, specifically including establishing a three-dimensional structural model of the workpiece, recording the vacuum requirements at different positions, the material of each part and the gas permeability of the corresponding material.

9. The vacuum extraction method for a large composite material workpiece according to claim 8, characterized in that: The vacuum degree requirement includes an initial vacuum degree value, a delay time, a test time, and a test critical value.

10. The vacuum extraction method for a large composite material workpiece according to claim 9, characterized in that: The area division in step S1 is divided into three steps: S121: Based on the three-dimensional structure model of the workpiece and the vacuum degree requirements at different positions, the surface area of ​​the workpiece is divided into unit cells using the finite element method; S122: classify all cells according to the surface characteristics of each cell; S123: Perform secondary classification on each cell according to the gas permeability of the material.

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