A method and apparatus for research of high performance thermoplastic composite co-consolidation injection molding process

Abstract

The present application is a research method and device for high-performance thermoplastic composite co-consolidation injection molding process, which characterizes the composite consolidation forming quality by tensile or tensile shear strength, and obtains a test piece level research method. The method can study the co-consolidation forming quality of different thermoplastic resins, thermosetting and thermoplastic resins, thermoplastic resins and other materials, and the influence of molding process parameters on the co-consolidation forming quality, and provide material level performance parameters and injection molding process parameters for different types of co-consolidation injection molding products. The test process of the method is easy to implement, the test parameter control is accurate, the test data is comprehensive, and the reliability is high.

Description

Technical Field

[0001] This invention relates to the fields of high-performance thermoplastic composite material molding and manufacturing technology and injection molding process, specifically to research methods and apparatus for co-consolidation injection molding process of high-performance thermoplastic composite materials. Background Technology

[0002] The application of high-performance thermoplastic composites in aerospace components has always been a research hotspot. High-performance thermoplastic composites do not require chemical reactions during the molding process, thus eliminating the need for a long wait for the resin chemical reaction to complete. Injection molding can be used to achieve rapid product manufacturing, reaching a production efficiency of "minutes".

[0003] Co-consolidated injection molding of thermoplastic composites is a rapid prototyping process that uses continuous fiber-reinforced thermoplastic composites as the reinforcing structure / skin and chopped fiber-reinforced thermoplastic composites as the skin / reinforcing structure. It can solve the problem of simultaneously achieving high quality and efficiency in injection molding. However, the bonding quality between the two components cannot be guaranteed and is difficult to detect using other equivalent methods. Validation with typical parts is time-consuming and costly, and cannot be used as a conventional research method. Therefore, the method of this invention allows for the study of specimen-level co-consolidated injection molding process parameters, thereby obtaining the optimal co-consolidated injection molding process parameters for the material. This helps improve the bond strength of the co-consolidated injection molding, facilitates product structure optimization design, reduces product production costs, and provides material-level performance parameters and injection molding process parameter references for different types of co-consolidated injection molding. Summary of the Invention

[0004] The purpose of this invention is to provide a research method for studying co-consolidation molding injection molding process, so that the injection molded products can be used to test the bonding quality between the two components during co-consolidation molding, and the bonding strength of co-consolidation injection molding can be improved by adjusting the process parameters.

[0005] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0006] A research method for co-consolidation injection molding process of high-performance thermoplastic composites includes the following steps:

[0007] (1) Select the first set of injection molding process parameters;

[0008] (2) Semi-sample preparation was carried out using co-consolidated injection molding tooling;

[0009] (3) Place the half sample in the position of the complete sample in the co-consolidation molding tooling, perform injection molding co-consolidation, and obtain the composite material co-consolidation connection strength test sample (i.e. the full sample) under the first set of process parameters. Then, test according to the quality evaluation index to obtain the first set of test data.

[0010] (4) Select the second set of injection molding process parameters, repeat steps (2) and (3) to obtain composite material co-consolidation connection strength test specimens under different injection molding process parameters, and conduct tests to obtain the second set of test data;

[0011] (5) By comparing the second set of test data with the first set of test data, relatively better co-consolidation injection molding process parameters can be obtained.

[0012] Furthermore, the above method can also compare more sets of test data, that is, it can also include the following steps:

[0013] Select the injection molding process parameters from group 3 to N, where N is an integer greater than or equal to 3, repeat the steps of half-sample preparation and injection molding co-consolidation to obtain composite material co-consolidation connection strength test samples under different injection molding process parameters, and conduct tests according to quality evaluation indicators to obtain test data from group 3 to N.

[0014] By comparing the test data from each group, the optimal process parameters for co-consolidation injection molding were obtained.

[0015] Furthermore, the selected injection molding process parameters to be studied, including mold temperature, screw temperature, holding pressure, and holding time, are used to design experiments with tensile strength and tensile shear strength as quality evaluation indicators.

[0016] Furthermore, the semi-sample formed in step (2) can be any one of thermoplastic resin, chopped fiber reinforced thermoplastic resin, continuous fiber reinforced thermoplastic prepreg, thermosetting resin, chopped fiber reinforced thermosetting resin, continuous fiber reinforced thermosetting prepreg, or metal. The complete test sample is prepared according to step (3) to study the injection molding bond strength between different materials.

[0017] Furthermore, the co-consolidation injection molding fixture includes a first runner, a second runner, a first runner slider, a second runner slider, a half-sample mold, and a full-sample mold. The half-sample mold is connected to the first runner, which is opened or closed using the first runner slider. The full-sample mold is connected to the second runner, which is opened or closed using the second runner slider. When the first runner slider is open and the second runner slider is closed, it can only be used for injection molding of half-samples; when the first runner slider is closed and the second runner slider is open, it can only be used for injection molding of full-samples (complete samples). By controlling the runner sliders, the test sample can be controlled to achieve the study of injection-molded co-consolidation strength of the same material or different materials under the same production process conditions.

[0018] Furthermore, the semi-sample mold includes a tensile semi-sample mold and a tensile shear semi-sample mold, which are respectively connected to the first flow channel; the full sample mold includes a tensile shear full sample mold and a tensile full sample mold, which are respectively connected to the second flow channel.

[0019] This invention also provides an apparatus for studying the co-consolidation injection molding process of high-performance thermoplastic composite materials. The apparatus includes a co-consolidation injection molding fixture comprising a first runner, a second runner, a first runner slider, a second runner slider, a half-sample mold, and a full-sample mold. The half-sample mold is connected to the first runner, which is opened or closed using the first runner slider. The full-sample mold is connected to the second runner, which is opened or closed using the second runner slider. When the first runner slider is open and the second runner slider is closed, it is only used for injection molding of half-samples; when the first runner slider is closed and the second runner slider is open, it is only used for injection molding of full-samples.

[0020] The present invention also provides a method for co-consolidation injection molding of high-performance thermoplastic composite materials. First, the optimal process parameters for co-consolidation injection molding are obtained according to the method of the present invention described above. Then, the thermoplastic composite material co-consolidation injection molding is performed according to the obtained optimal process parameters.

[0021] Compared with existing research methods, this invention can obtain the optimal co-consolidation injection molding process parameters for materials by studying the co-consolidation injection molding process parameters at the specimen level. This improves the co-consolidation injection molding bond strength, facilitates product structure optimization design, reduces the number of typical part-level process tests and product mold repairs, and helps reduce product production costs. Furthermore, it provides material-level performance parameters and injection molding process parameters for different types of co-consolidation injection molded products. The experimental process of this method is easy to implement, the experimental parameters are precisely controlled, and the test data is comprehensive and highly reliable. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the co-consolidated injection molding tooling of the present invention.

[0023] Figure 2 This is a schematic diagram of a half-sample in this invention, wherein (a) is a tensile half-sample and (b) is a tensile shear half-sample.

[0024] Figure 3 This is a schematic diagram of the full specimen in this invention, where (a) is a tensile full specimen and (b) is a tensile shear full specimen.

[0025] In the figure: 1. Tensile semi-sample mold; 2. First runner slider; 3. Tensile shear semi-sample mold; 4. Second runner slider; 5. Tensile shear full sample mold; 6. Tensile full sample mold; 7. First runner; 8. Second runner; 9. Injection port. Specific implementation methods

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Figure 1 This is a schematic diagram of the co-consolidation injection molding fixture of the present invention, including a tensile half-sample mold 1, a first runner slider 2, a tensile shear half-sample mold 3, a second runner slider 4, a tensile shear full-sample mold 5, a tensile full-sample mold 6, a first runner 7, a second runner 8, and a injection port 9. The tensile half-sample mold 1 and the tensile shear half-sample mold 3 are respectively connected to the first runner 7, which is opened or closed using the first runner slider 2. The tensile shear full-sample mold 5 and the tensile full-sample mold 6 are respectively connected to the second runner 8, which is opened or closed using the second runner slider 4. When the first runner slider 2 is open and the second runner slider 4 is closed, it can only be used for injection molding half-samples; when the first runner slider 2 is closed and the second runner slider 4 is open, it can only be used for injection molding full-samples (complete samples). By controlling the runner sliders, the test samples can be controlled to achieve the study of injection-molded co-consolidation strength of the same or different materials under the same production process conditions.

[0028] The flow channel slider can be connected to the flow channel via bolts. The flow channel slider has an elongated groove; when the bolts are loosened, the flow channel slider can slide, opening or closing the flow channel, acting like a valve. After the flow channel slider is adjusted, tightening the bolts will fix its position. Alternatively, the flow channel slider can also be connected to the flow channel using other suitable methods.

[0029] Example 1: Study on the effect of mold temperature on the self-co-consolidation strength of short fiber reinforced polyetheretherketone composites

[0030] 1) Place the chopped fiber reinforced polyether ether ketone granules in a tray, spread them out and put them into a forced-air drying oven for drying. Set the drying temperature to 150℃ and dry for more than 4 hours.

[0031] 2) Turn on the injection molding equipment and install the co-consolidated injection molding fixture. The co-consolidated injection molding fixture is as follows: Figure 1As shown, the tooling adjusts the first flow channel slider 2 to open it and the second flow channel slider 4 to close it. The temperatures of each zone of the injection molding machine screw from head to tail are 390℃, 385℃, 380℃, 375℃, and 370℃, respectively. The mold temperature of the co-bonded injection tooling is set to 200℃. According to the injection volume, the material storage position is set to 50mm, the injection position is set to 10mm, and the holding pressure is 50MPa.

[0032] 3) After each module reaches the preset temperature, keep it warm for 30 minutes and then start injection molding.

[0033] 4) Remove the tensile shear half-specimen from the tensile shear half-specimen mold 3, and repeat the injection molding process 5 times to obtain 5 tensile shear half-specimens. The tensile shear half-specimens are as follows: Figure 2 As shown in (b).

[0034] 5) Put on heat-resistant gloves and adjust the co-consolidation injection fixture to close the first runner slider 2 and open the second runner slider 4.

[0035] 6) Fix the removed tensile shear half specimen into the concave mold of the template core mold, i.e., the tensile shear full specimen mold 5.

[0036] 7) Begin injection molding to obtain a complete co-consolidated specimen for testing, i.e., a full tensile shear specimen, such as... Figure 3 As shown in (b).

[0037] 8) Tensile shear tests were performed on the self-consolidated specimens of short fiber reinforced polyether ether ketone composite material, and the data are shown in Table 1.

[0038] Table 1. Self-co-consolidation strength of short fiber reinforced polyetheretherketone composites at a mold temperature of 200℃

[0039] Tensile shear strength / MPa 3.52 3.34 3.67 3.11 3.16 3.36 7.1％

[0040] 9) After obtaining 5 tensile shear half specimens by repeating steps 1) to 4), adjust the mold temperature of the co-consolidation injection tooling to 220°C. After the temperature is reached, keep it at that temperature for 30 minutes. Repeat steps 5) to 8) to obtain the self-co-consolidation strength of the short fiber reinforced polyether ether ketone composite material at a mold temperature of 220°C, as shown in Table 2.

[0041] Table 2.2 Self-co-consolidation strength of short fiber reinforced polyetheretherketone composites at a mold temperature of 220℃

[0042] Tensile shear strength / MPa 4.52 3.89 4.41 4.12 3.96 4.18 6.6％

[0043] By comparing the self-co-consolidation strength of short fiber reinforced polyether ether ketone composite materials under the two mold temperatures mentioned in Tables 1 and 2, it can be found that adjusting the mold temperature during co-consolidation molding can effectively improve the self-co-consolidation strength of the material, which is beneficial to improving the product molding quality.

[0044] Example 2: Study on the co-consolidation strength of polyetheretherketone and polyaryletherketone

[0045] 1) Place the polyetheretherketone and polyaryletherketone granules in different trays, spread them out and put them into a forced-air drying oven for drying. Set the drying temperature to 150℃ and dry for more than 4 hours.

[0046] 2) Turn on the injection molding equipment and install the co-bonded injection molding fixture, such as... Figure 1 As shown, the tooling adjusts the first flow channel slider 2 to open it and the second flow channel slider 4 to close it. The temperatures of each zone of the injection molding machine screw from head to tail are 390℃, 385℃, 380℃, 375℃, and 370℃, respectively. The mold temperature of the co-bonded injection tooling is set to 200℃. According to the injection volume, the material storage position is set to 50mm, the injection position is set to 10mm, and the holding pressure is 50MPa.

[0047] 3) After each module reaches the preset temperature, keep it warm for 30 minutes and then start injection molding of polyetheretherketone.

[0048] 4) Remove the tensile shear half specimen from the tensile shear half specimen mold 3, and repeat the injection molding process 5 times to obtain 5 specimens respectively.

[0049] 5) Put on heat-resistant gloves and adjust the co-consolidation injection fixture to close the first runner slider 2 and open the second runner slider 4.

[0050] 6) Empty the injection molding machine barrel and add polyaryletherketone to clean the barrel. Then fix the removed tensile shear half specimen into the cavity of the template core mold, i.e., the tensile shear full specimen mold 5.

[0051] 7) Begin injection molding of polyaryletherketone to obtain the polyaryletherketone / polyaryletherketone co-bonded sample for testing.

[0052] 8) Tensile shear tests were performed on the co-consolidated specimens, and the data are shown in Table 3.

[0053] Table 3. Co-consolidation strength of polyetheretherketone and polyaryletherketone

[0054] Tensile shear strength / MPa 7.96 8.04 8.23 7.78 8.41 8.08 3.1％

[0055] By comparing the self-co-consolidation strength of polyetheretherketone (PEEEK) and the co-consolidation strength of PEEEK / polyaryletherketone (PREE) at the same mold temperature in Tables 1 and 3, it can be found that when PREE is selected as the secondary co-consolidation material, its co-consolidation with the matrix PEEEK is better, which can effectively improve the product molding quality.

[0056] In other embodiments of the present invention, tensile half-samples and tensile full-samples can be prepared using tensile half-sample mold 1 and tensile full-sample mold 6 according to the above steps, such as... Figure 2 (a) Figure 3 As shown in (a).

[0057] In the above embodiment, the first flow channel has two branch flow channels, such as... Figure 1 As shown, the molds are connected to the tensile half-sample mold 1 and the tensile shear half-sample mold 3, respectively, so that tensile half-samples and tensile shear half-samples are obtained simultaneously during molding. In other embodiments, sliders can be provided in the branch flow channels to allow for separate control of the molding processes of the tensile half-sample mold 1 and the tensile shear half-sample mold 3. Similarly, the second flow channel also has two branch flow channels, connected to the tensile full-sample mold 5 and the tensile shear full-sample mold 6, respectively, so that tensile full-samples and tensile shear full-samples are obtained simultaneously during molding. In other embodiments, sliders can also be provided in the branch flow channels to allow for separate control of the molding processes of the tensile full-sample mold 5 and the tensile shear full-sample mold 6.

[0058] Based on the above embodiments, by changing the injection molding process parameters, the influence of each process parameter on the co-consolidation bond strength of the product can be studied.

[0059] Based on the above embodiments, by modifying the surface condition of the co-bonded bonding surface, the influence of various surface treatment methods on the co-bonded bonding strength of the product can be studied.

[0060] Based on the above embodiments, by changing different secondary co-consolidation materials, the bonding strength between different materials and the matrix can be studied.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A research method for high performance thermoplastic composite co-consolidation injection molding process, characterized in that, Includes the following steps: Select the first set of injection molding process parameters; Semi-samples were prepared using a co-consolidation injection molding tooling; the materials used for preparing the semi-samples were either chopped fiber reinforced thermoplastic resin or continuous fiber reinforced thermoplastic prepreg. The half-sample was placed in the position of the complete sample in the co-consolidation injection molding tooling, and injection molding co-consolidation was performed to obtain the composite material co-consolidation connection strength test sample under the first set of process parameters. The test was carried out according to the quality evaluation index to obtain the first set of test data. The second set of injection molding process parameters was selected, and the steps of half-sample preparation and injection co-consolidation were repeated to obtain composite material co-consolidation connection strength test samples under different injection molding process parameters. The test was carried out according to the quality evaluation index to obtain the second set of test data. By comparing the second set of test data with the first set of test data, relatively optimal co-consolidation injection molding process parameters were obtained. The co-consolidated injection molding fixture includes a first runner, a second runner, a first runner slider, a second runner slider, a half-sample mold, and a full-sample mold. The half-sample mold is connected to the first runner, which is opened or closed using the first runner slider. The full-sample mold is connected to the second runner, which is opened or closed using the second runner slider. When the first runner slider is open and the second runner slider is closed, it is only used for injection molding of half-samples. When the first runner slider is closed and the second runner slider is open, it is only used for injection molding of full-samples.

2. The method of claim 1, wherein, It also includes the following steps: Select the injection molding process parameters from group 3 to N, where N is an integer greater than or equal to 3, repeat the steps of half-sample preparation and injection molding co-consolidation to obtain composite material co-consolidation connection strength test samples under different injection molding process parameters, and conduct tests according to quality evaluation indicators to obtain test data from group 3 to N. By comparing the test data from each group, the optimal process parameters for co-consolidation injection molding were obtained.

3. The method of claim 1, wherein, The semi-sample mold includes a tensile semi-sample mold and a tensile shear semi-sample mold, which are respectively connected to the first flow channel; the full sample mold includes a tensile shear full sample mold and a tensile full sample mold, which are respectively connected to the second flow channel.

4. The method of claim 1, wherein, By controlling the test specimen through the first flow channel slider and the second flow channel slider, the study of injection molding co-consolidation strength of the same material or different materials under the same production process conditions can be realized.

5. The method according to claim 1 or 2, characterized in that, The injection molding process parameters include at least one of mold temperature, screw temperature, holding pressure, and holding time.

6. The method of claim 1 or 2, wherein, The quality evaluation index is at least one of tensile strength and tensile shear strength.

7. An apparatus for the research of the co-consolidation injection molding process of high performance thermoplastic composites implementing the method of any one of claims 1 to 6, characterized in that, The system includes a co-consolidated injection molding fixture, comprising a first runner, a second runner, a first runner slider, a second runner slider, a half-sample mold, and a full-sample mold. The half-sample mold is connected to the first runner, which is opened or closed using the first runner slider. The full-sample mold is connected to the second runner, which is opened or closed using the second runner slider. When the first runner slider is open and the second runner slider is closed, the system is used only for injection molding half-samples. When the first runner slider is closed and the second runner slider is open, the system is used only for injection molding full-samples.

8. A method for co-consolidation injection molding of high-performance thermoplastic composite materials, characterized in that, The optimal process parameters for co-consolidation injection molding are obtained by the method according to any one of claims 1 to 6, and the thermoplastic composite material co-consolidation injection molding is performed according to the obtained optimal process parameters.

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