A molding method for composite material ribs

Abstract

This invention discloses a method for molding composite material ribs, comprising the following steps: S1: tooling preparation; S2: part laying; S3: mold closing and pre-compression; after the upper and lower molds of the tooling are closed, the upper mold is removed, the frame of the upper mold is also removed, the screws between the upper mold and the frame are removed, and then the part is separated from the upper mold by using tools, thus demolding the part; S4: bag making; after the upper mold is removed, the side pressure plate and pressure block are installed to make a vacuum bag; S5: curing; S6: demolding; S7: edge trimming and drilling. This invention mainly solves the problems of pores and white spots appearing on the web surface of parts during the curing process of existing compression molding by changing the compression molding to bag-making compression molding after the upper and lower molds are laid, and then removing the upper mold after pre-compression. Combined with specific process steps and parameter design, this improves the molding quality of composite material ribs.

Description

Technical Field

[0001] This invention relates to the field of molding technology for composite material ribs, and more specifically to a molding method for composite material ribs. Background Technology

[0002] Composite ribs are widely used in critical load-bearing components in aerospace, aircraft wings, satellite supports, wind power, and rail transportation, combining the advantages of lightweight and high strength. Their manufacturing process requires addressing key issues such as efficient connection between the web and flanges, fiber continuity and orientation control, internal quality, and geometric accuracy.

[0003] Existing composite material rib molding processes mainly include RTM / VaRTM molding and compression molding. RTM molding has problems such as uneven resin flow leading to dry spots / pores and low positioning accuracy of the preform.

[0004] When composite material ribs are formed by compression molding, the gas inside the molding cavity is difficult to escape during curing, resulting in insufficient venting of the material sheet. This leads to defects such as air holes and white spots on the web surface of the part after molding. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for forming composite material ribs. This method addresses the problem of defects such as pores and white spots on the web surface of parts caused by insufficient venting of the material sheet during compression molding and curing. The invention mainly solves the problem of defects such as pores and white spots on the web surface of parts during compression molding and curing by changing the compression molding process to bag compression molding, after the upper and lower molds are laid and pre-compressed. After pre-compression, the upper mold is removed. This invention, combined with specific process steps and parameter design / optimization, can solve the problem of defects such as pores and white spots on the web surface of parts during compression molding and curing, thereby improving the forming quality of composite material ribs.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for molding a composite material rib, characterized by comprising the following steps:

[0008] S1: Tooling preparation; the tooling includes the lower mold assembly, upper mold assembly, pressure plate, and pressure block. Clean the tooling thoroughly and apply release agent.

[0009] S2: Component placement;

[0010] S21: Develop a layup schedule: Lay up the layers in the order of the layup schedule, covering a total of 4 areas. Lay up the upper mold, lay up the lower mold, lay up the lower mold between the upper and lower molds before closing the mold, and finally lay up the side after closing the mold.

[0011] S3: Mold closing and pre-pressing; After the upper and lower molds of the tooling are closed, the upper mold is removed, and the frame of the upper mold is also removed. The screws between the upper mold and the frame are removed. The screws on the back of the upper mold are removed using tools. Then, the parts are lifted and separated from the upper mold using tools, so that the parts are demolded.

[0012] S4: Bag making; After removing the upper mold, install the side pressure equalizing plate and pressure block to make vacuum bags;

[0013] S5: Curing;

[0014] S6: Demolding;

[0015] S7: Edge cutting and drilling;

[0016] S8: Inspection.

[0017] Furthermore, in S2: during the layup, the upper and lower molds are laid separately, and the material sheet is laid from the center of the web of the mold body to the side edge strips. The fabric laying angle deviation is ±5°, of which the unidirectional strip laying angle deviation is ±3°.

[0018] Before laying each layer of material, after peeling off the backing paper on one side, the material on that side needs to be inspected for any excess. After laying the material, after peeling off the backing paper on the other side, the material on that side needs to be inspected for any excess. If there is any excess, it should be removed from the material in time. Only after this process is completed can the next layer be laid.

[0019] S22: First, lay a layer of release film on the model surface of the tooling, and then lay the material sheet on the release film. The release film is laid to the thickness control area of ​​the upper mold of the tooling. The first layer of material sheet of the upper mold is partially laid to the thickness control area. Subsequent material sheets are laid at a distance of 3mm from the thickness control area. Note that the material sheet laying must pass through the part position line.

[0020] S23: The material sheet is directly laid on the lower mold of the tooling. The material sheet is laid into the thickness control area of ​​the lower mold. After the upper and lower molds are laid, the mold is closed. After the mold is closed, another tooling is placed on top of the mold closing tooling for pre-pressing. The pre-pressing time is more than 30 minutes. Then, the vacuum is pre-extracted. During the pre-vacuuming, the twisted wire is laid together and the pre-vacuuming is completed. After the pre-vacuuming is completed, the condition of the twisted wire is checked. According to the condition of the twisted wire, the subsequent side plate is laid.

[0021] S24: When laying the side layer, place carbon twisted wire strips in the middle ring after the mold is closed. The twisted wires need to be compacted in place. After the twisted wires are filled and compacted, they should protrude slightly. After filling the twisted wires, vacuum for 20 minutes and observe the state of the twisted wires. If the twisted wires are concave, fill them with more twisted wires to make them protrude slightly before laying the side panels.

[0022] S25: After the side layer is laid, lay another layer of high-temperature wet peelable cloth. After the upper mold is removed, lay the high-temperature wet peelable cloth on the web of the part, the web of the upper mold and the inner side plate. The wet peelable cloth at the R-corner of the part needs to be cut off.

[0023] Furthermore, in S3: after the upper and lower molds of the tooling are closed and before the upper mold is removed, after the upper and lower mold material sheets are laid, a layer of non-porous film is covered on the surface of the upper and lower molds. The upper mold is rotated 180° using a flipping tool, and the flipping tool together with the upper mold is hoisted using a tool. It is then closed with the lower mold using guide pillars, and the non-porous film is removed. After the closure is completed, the screws in the upper mold flipping tool and the upper mold are removed, and the flipping tool is taken out using a tool. When closing the mold, a pressure equalizing plate is placed, and a copper pad with a thickness of 1.0mm is placed on the pressure equalizing plate for thickness control.

[0024] Furthermore, in S4: at least two thermocouples are installed at the edge of the part's allowance, and the thermocouple numbers are recorded in the inspection record page; two vacuum nozzles are placed at the diagonal position of the lower mold of the tooling, one for evacuation and one for testing; the vacuum test requires evacuation to at least -85 kPa, and the vacuum drop should not exceed 3 kPa within 10 minutes. Only after passing the vacuum test can the part be put into the tank.

[0025] Furthermore, in S5:

[0026] S51: Before curing begins, fill in the air tightness check record in the layup record sheet;

[0027] S52: Evacuate to 0.09~0.098MPa, heat to 80±5℃ at a rate of less than 3℃ / min, apply external pressure of 0.5±0.03MPa when the temperature reaches 80±5℃, close the vacuum and vent to the atmosphere when the pressure reaches 0.1MPa, and maintain the temperature and pressure for 10~40min when the pressure reaches 0.5±0.03MPa; after the heat preservation, continue to heat to 180±5℃ at a rate of less than 3℃ / min, and maintain the temperature and pressure for 120~300min when the temperature reaches 180±5℃; after the heat preservation, cool down to below 60℃ at a rate of less than 3℃ / min, then depressurize, and when the pressure drops to 0.08~0.15MPa, open the vacuum and maintain it for more than 10min until the product is discharged from the tank.

[0028] Further, in S6: Remove the pressure block of the part, and then gently remove the pressure plate; after removing the side pressure block and the pressure plate, use a scraper to clean the glue accumulated in the center dividing groove, and use a copper scraper or composite wedge to demold the part in the remaining area. When demolding, be careful not to damage the part and the tooling surface.

[0029] Furthermore, in S7:

[0030] S71: Cutting: Use a pneumatic cutting machine to roughly cut the outer contour of the part according to the part line, leaving a margin of 0.5~1mm relative to the cutting line. After cutting, use a grinder to repair the edge burrs and the left margin, and retain the cutting line; after submitting for inspection and passing the inspection, use sandpaper dipped in water to grind away the raised cutting line.

[0031] S72: Drilling: Select the appropriate drill bit to drill holes in the part, and finally use a reamer to ream the holes and remove burrs.

[0032] This invention discloses a method for molding composite material ribs, which addresses the problem of defects such as pores and white spots on the web surface of parts caused by insufficient venting of the material sheet during molding and curing. The invention primarily improves the molding quality by changing the molding process to bag-making molding, where the upper and lower molds are laid out and then pre-pressed (pre-compacted). After pre-compacting, the upper mold is removed. This method, combined with specific process steps and parameter design / optimization, solves the problem of pores and white spots on the web surface of parts during molding and curing, thus improving the overall quality of composite material rib molding. Detailed Implementation

[0033] To make the technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in a clearer and more complete manner below. It should be understood that the specific embodiments described herein are only some embodiments of the present invention, and are only used to explain the present invention, not to limit the present invention.

[0034] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Furthermore, unless otherwise defined, the technical or scientific terms used in the description of this invention should have the ordinary meaning understood by those skilled in the art.

[0035] A method for molding a composite material rib, characterized by comprising the following steps:

[0036] S1: Tooling preparation;

[0037] The tooling consists of components such as a lower mold assembly, an upper mold assembly, a pressure plate, and pressure blocks. These components and their internal parts are removed from the tooling, cleaned, and then a release agent is applied.

[0038] S2: Component placement;

[0039] S21: Develop a layup schedule: Lay up the layers in the order of the layup schedule, covering a total of 4 areas. Lay up the upper mold, lay up the lower mold, lay up the lower mold between the upper and lower molds before closing the mold, and finally lay up the side after closing the mold.

[0040] During the layup process, the upper and lower molds are laid separately, and the material / sheet is laid from the center of the web of the mold body to the side edge strips. The fabric laying angle deviation is ±5°, and the unidirectional strip laying angle deviation is ±3°.

[0041] Before laying each layer of material, after peeling off the backing paper on one side, the material on that side must be inspected for any excess material (such as hair, scraps of backing paper, fragments of release film, and all other material-related debris). After laying the material on that side, peel off the backing paper on the other side and inspect the material on that side for any excess material. If any excess material is found, it must be removed from the material in a timely manner. Only after this process is completed can the subsequent layers be laid.

[0042] S22: First, lay a layer of release film on the model surface of the tooling, and then lay the material sheet on the release film. The release film is laid to the thickness control area of ​​the upper mold of the tooling. The first layer of material sheet of the upper mold is partially laid to the thickness control area. Subsequent material sheets are laid at a distance of 3mm from the thickness control area. Note that the material sheet laying must pass through the part position line.

[0043] S23: Directly lay the material sheet onto the lower mold of the tooling. Lay the material sheet into the thickness control area of ​​the lower mold. After the upper and lower molds are laid, close the mold. After the mold is closed, use another tooling to place on top of the mold closing tooling for pre-pressing. Pre-press for more than 30 minutes, and then perform pre-extraction (vacuuming). During pre-extraction, lay the twisted wire together and then perform pre-extraction. After the pre-extraction is completed, check the condition of the twisted wire. Based on the condition of the twisted wire, then lay the subsequent side plates.

[0044] S24: When laying the side layer, place carbon twisted wire strips in the middle ring after the mold is closed. The twisted wires need to be compacted in place. After the twisted wires are filled and compacted, they should protrude slightly / partially. After filling the twisted wires, vacuum for 20 minutes and observe the state of the twisted wires. If the twisted wires are concave, fill them with more twisted wires to make them protrude slightly before laying the side panels.

[0045] S25: After the side layer is laid, lay another layer of high-temperature wet peelable cloth. After the upper mold is removed, lay the high-temperature wet peelable cloth on the web of the part, the web of the upper mold and the inner side plate. The wet peelable cloth at the R-corner of the part needs to be cut off.

[0046] S3: Mold closing pre-compression;

[0047] After the upper and lower mold sheets are laid, a non-porous film is covered on the surface of the upper and lower molds. The upper mold is rotated 180° using a flipping fixture, and the flipping fixture is hoisted together with the upper mold using tools. It is then closed with the lower mold using guide columns, and the non-porous film is removed. After closure, the screws in the upper mold flipping fixture and the upper mold are removed, and the flipping fixture is taken out using tools.

[0048] When the mold is closed, place a pressure equalizing plate and place a 1.0mm thick copper pad on the pressure equalizing plate for thickness control; after the upper and lower molds of the tooling are closed, remove the upper mold and the frame of the upper mold, remove the screws of the upper mold and the frame, use tools to remove the screws on the back of the upper mold, and then use tools to lift and separate the part from the upper mold, so that the part is demolded.

[0049] S4: Bag making;

[0050] After removing the upper mold, install the side pressure equalizing plate and pressure block to make vacuum bags;

[0051] Among these requirements, at least two thermocouples must be installed at the edge of the part's allowance, and the thermocouple numbers must be recorded in the inspection record page; two vacuum nozzles must be placed at the diagonal position of the lower mold of the tooling, one for evacuation and one for testing; the vacuum test requires evacuation to at least -85 kPa, and the vacuum drop must not exceed 3 kPa within 10 minutes. Only parts that pass the vacuum test can be put into the tank.

[0052] S5: Curing;

[0053] S51: Before curing begins, fill in the air tightness check record in the layup record sheet;

[0054] S52: Evacuate to 0.09~0.098MPa, and heat to 80±5℃ at a rate of less than 3℃ / min (preferably 1.5℃ / min). When the temperature reaches 80±5℃ (hysteresis coupling), apply an external pressure of 0.5±0.03MPa (air coupling set temperature is 85℃). When the pressure reaches 0.1MPa, close the vacuum and allow atmospheric flow. When the pressure reaches 0.5±0.03MPa, maintain the temperature and pressure for 10~40min (preferably 30min). After the heat preservation is completed... Continue heating at a rate of less than 3℃ / min (set to 1.5℃ / min) to 180±5℃. When the temperature reaches 180±5℃, maintain the temperature and pressure for 120~300min (set to 180min). After the temperature maintenance, cool down to below 60℃ (set to 50℃) at a rate of less than 3℃ / min (set to 1.5℃ / min). Then depressurize. When the pressure drops to 0.08~0.15Mpa, open the vacuum pump and maintain it for more than 10min until the contents are removed from the tank.

[0055] S6: Demolding;

[0056] Remove the pressure blocks from the parts, and then gently remove the pressure equalizing plate.

[0057] After removing the side pressure blocks and equalizing plates, use a scraper to clean the accumulated glue at the center dividing groove. Use a copper scraper or composite wedge to remove the part from the mold in the remaining area. Take care not to damage the part or the tooling surface when removing the mold.

[0058] S7: Edge cutting and drilling;

[0059] S71: Cutting: Use a pneumatic cutting machine to roughly cut the outer contour of the part according to the part line, leaving a margin of 0.5~1mm relative to the cutting line. After cutting, use a grinder to repair the edge burrs and the left margin, and retain the cutting line; after submitting for inspection and passing the inspection, use sandpaper dipped in water to grind away the raised cutting line.

[0060] S72: Drilling: Select the appropriate drill bit to drill holes in the part, and finally use a reamer to ream the holes and remove burrs.

[0061] S8: Inspection;

[0062] Inspect the shape, dimensions, and surface quality of the parts, and record the inspection results.

[0063] This invention discloses a method for molding composite material ribs, which addresses the problem of defects such as pores and white spots on the web surface of parts caused by insufficient venting of the material sheet during molding and curing. The invention primarily improves the molding quality by changing the molding process to bag-making molding, where the upper and lower molds are laid out and then pre-pressed (pre-compacted). After pre-compacting, the upper mold is removed. This method, combined with specific process steps and parameter design / optimization, solves the problem of pores and white spots on the web surface of parts during molding and curing, thus improving the overall quality of composite material rib molding.

[0064] The above embodiments are illustrative of the present invention and not intended to limit the invention. It is understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for molding a composite material rib, characterized in that, Includes the following steps: S1: Tooling preparation The tooling includes a lower mold assembly, an upper mold assembly, a pressure plate, and a pressure block. After cleaning the tooling, apply a release agent evenly. S2: Component installation The upper and lower molds are laid separately. The material sheet is laid from the center of the web of the mold body to the side edge strips. The fabric laying angle deviation is ±5° and the unidirectional tape laying angle deviation is ±3°. Before laying each layer of material, peel off one side of the backing paper to check for excess material; after laying, peel off the other side of the backing paper for a second inspection and cleaning; after the cleaning is completed, continue laying layers. S3: Mold closing pre-compression After the upper and lower molds of the tooling are closed, the upper mold is removed, and the frame of the upper mold is also removed. The screws between the upper mold and the frame are removed, and the parts are lifted and separated from the upper mold to achieve demolding. After the upper and lower molds are closed, before removing the upper mold, after the upper and lower mold sheets are laid, the surfaces of the upper and lower molds are covered with a non-porous film. The upper mold is rotated 180° using a flipping fixture. After hoisting, it is closed with the lower mold using guide columns, and the non-porous film is removed. After closing, the screws in the upper mold flipping fixture and the upper mold are removed, and the flipping fixture is removed using tools. When closing the mold, a pressure equalizing plate is placed, and a copper pad with a thickness of 1.0mm is placed on the pressure equalizing plate to control the thickness. S4: Bag making After removing the upper mold, install the side pressure plate and pressure block to make a vacuum bag; Among them, at least two thermocouples are installed on the edge of the spare parts, and the thermocouple numbers are recorded; two vacuum nozzles are placed diagonally on the lower mold, one for evacuation and one for testing; the vacuum test requires evacuation to at least -85kPa, and the vacuum drop should not exceed 3kPa within 10 minutes. After passing the test, the parts are put into the tank. S5: Curing; S6: Demolding. Remove the pressure block of the part, remove the pressure plate, clean the glue accumulated in the center dividing groove, use a copper scraper or composite wedge to lift the part in the remaining area, and demold the part to avoid damaging the part and tooling surface. S7: Edge cutting and drilling; S8: Inspection.

2. The molding method of a composite material rib as described in claim 1, characterized in that, In S2: S21: Develop a layup schedule and lay up the layers in the order of the layup schedule. There are a total of 4 areas to be laid: upper mold, lower mold, lower mold position between the upper and lower molds before mold closing, and finally side layup after mold closing. S22: First, lay a layer of release film on the model surface of the tooling, and then lay the material sheet on the release film. The release film is laid to the thickness control area of ​​the upper mold of the tooling. The first layer of material sheet of the upper mold is partially laid to the thickness control area. Subsequent material sheets are laid at a distance of 3mm from the thickness control area. Note that the material sheet laying must pass through the part position line. S23: The material sheet is directly laid on the lower mold of the tooling. The material sheet is laid into the thickness control area of ​​the lower mold. After the upper and lower molds are laid, the mold is closed. After the mold is closed, another tooling is placed on top of the mold closing tooling for pre-pressing. The pre-pressing time is more than 30 minutes. Then, the vacuum is pre-extracted. During the pre-vacuuming, the twisted wire is laid together and the pre-vacuuming is completed. After the pre-vacuuming is completed, the condition of the twisted wire is checked. According to the condition of the twisted wire, the subsequent side plate is laid. S24: When laying the side layer, place carbon twisted wire strips in the middle ring after the mold is closed. The twisted wires need to be compacted in place. After the twisted wires are filled and compacted, they should protrude slightly. After filling the twisted wires, vacuum for 20 minutes and observe the state of the twisted wires. If the twisted wires are concave, fill them with more twisted wires to make them protrude slightly before laying the side panels. S25: After the side layer is laid, lay another layer of high-temperature wet peelable cloth. After the upper mold is removed, lay the high-temperature wet peelable cloth on the web of the part, the web of the upper mold and the inner side plate. The high-temperature wet peelable cloth at the R-corner of the part needs to be cut off.

3. The molding method for a composite material rib as described in claim 1, characterized in that, In S5: S51: Before curing begins, fill in the air tightness check record in the layup record sheet; S52: Evacuate to 0.09~0.098MPa, heat to 80±5℃ at a heating rate of less than 3℃ / min, when the temperature reaches 80±5℃, apply external pressure of 0.5±0.03MPa, when the pressure reaches 0.1MPa, close the vacuum and vent to the atmosphere, when the pressure reaches 0.5±0.03MPa, maintain the temperature and pressure for 10~40min; after the heat preservation, continue to heat to 180±5℃ at a heating rate of less than 3℃ / min, when the temperature reaches 180±5℃, maintain the temperature and pressure for 120~300min; after the heat preservation, cool down to below 60℃ at a cooling rate of less than 3℃ / min, then depressurize, when the pressure drops to 0.08~0.15MPa, open the vacuum, maintain for more than 10min, until the product is discharged from the tank.

4. The molding method of a composite material rib as described in claim 1, characterized in that, In S7: S71: Cutting: Use a pneumatic cutting machine to roughly cut the outer contour of the part according to the part line, leaving a margin of 0.5~1mm relative to the cutting line. After cutting, use a grinder to repair the edge burrs and the left margin, and retain the cutting line; after submitting for inspection and passing the inspection, use sandpaper dipped in water to grind away the raised cutting line. S72: Drilling: Select the appropriate drill bit to drill holes in the part, and finally use a reamer to ream the holes and remove burrs.