Forming method of composite rib plate

Abstract

The invention discloses a forming method of a composite rib plate. The forming method comprises the following steps that S1, a tool is prepared; s2, paving the parts; s3, mold closing and pre-pressing; after the upper mold and the lower mold of the tool are assembled, the upper mold is taken out, a frame of the upper mold is also taken out, screws of the upper mold and the frame are removed, then a tool is used for hoisting to separate the part from the upper mold, and the part is demolded; s4, bag making; after the upper mold is taken down, a pressure equalizing plate and a pressing block on the side edge are installed, and a vacuum bag is manufactured; s5, curing is conducted; s6, demolding is conducted; and S7, trimming and drilling. According to the method, mold closing and pre-compaction are carried out after compression molding is changed into paving of the upper mold and the lower mold, the upper mold is taken down after pre-compaction is completed, compression molding is changed into bag pressing molding of bag making, and specific process steps and parameter design are matched, so that the bag making efficiency is improved. The problems of air holes, white spots and other defects on a part web plate surface during existing compression molding curing can be solved, and the forming quality of the composite rib plate is improved.

Description

Technical Field

[0001] The invention relates to the technical field of composite material rib forming technology, and in particular to a composite material rib forming method. Background Art

[0002] Composite ribs are widely used as key load-bearing components in aerospace, aircraft wings, satellite mounts, wind power, rail transit, and other fields. They combine lightweighting with high strength. Their manufacturing process requires addressing key issues such as efficient connection between the web and flange, fiber continuity and orientation control, internal quality, and geometric accuracy.

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

[0004] When using the compression molding method to form composite material ribs, the gas inside the molding cavity is difficult to be discharged during curing, and the sheet is not sufficiently vented, resulting in defects such as pores and white spots on the web surface of the part after molding. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for forming composite material ribs, which is used to solve the problem of defects such as pores and white spots on the web surface of the part due to insufficient exhaust of the sheet during compression molding and curing. The present invention mainly changes the compression molding to a method of closing the mold for pre-pressing (pre-compacting) after the upper and lower molds are laid, and after the pre-compacting is completed, the upper mold is removed, and the compression molding is changed to bag pressing for bag making. In combination with specific process steps and parameter design / optimization, the present invention can solve the problem of defects such as pores and white spots on the web surface of the part during the curing of the existing compression molding, thereby improving the molding quality of the composite material ribs.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: A method for forming a composite material rib, characterized in that it comprises the following steps: S1: Tooling preparation; the tooling includes the lower mold assembly, upper mold assembly, equalizing plate, and pressing block. Clean the tooling and apply release agent; S2: Laying of parts; S21: Prepare a layup table: Lay out the tiles in the order of the layup table. There are four areas in total: the upper mold, the lower mold, the lower mold between the upper and lower molds before mold closing, and finally the side after mold closing. S3: Mold closing and pre-pressing; 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, the screws on the back of the upper mold are removed using tools, and then the part is separated from the upper mold by lifting using tools, resulting in the part being demoulded; S4: Bag making: After removing the upper mold, install the side pressure plate and the pressure block to make the vacuum bag; S5: curing; S6: demoulding; S7: cutting edge drilling; S8: Inspection.

[0007] Furthermore, in S2: wherein, when laying, the upper mold and the lower mold are laid separately, and the material sheet is laid from the center of the web of the mold body to the edge strips on both sides, and the laying angle deviation of the fabric is ±5°, wherein the laying angle deviation of the unidirectional tape is ±3°; Before laying each layer of material, after tearing off the backing paper on one side, the material on that side needs to be inspected for excess material. After laying the material, after tearing off the backing paper on the other side, the material on the other side needs to be inspected for excess material. If there is any excess material, it should be removed from the material in time, and the subsequent layer can be laid only after the processing is completed. S22: First, lay a layer of isolation film on the upper mold surface of the tooling, and then lay the blanks on the isolation film. The isolation film is laid to the thickness control area of ​​the upper mold of the tooling. The first layer of blanks of the upper mold is partially laid to the thickness control area. The subsequent blanks are laid at a distance of 3mm from the thickness control area. Note that the blanks must be laid across the part position line. S23: directly lay the sheet on the lower mold of the tooling, and lay the sheet to 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 the mold closing tooling for pre-pressing for more than 30 minutes, and then pre-vacuuming is performed. During the pre-vacuuming, the twisted wire is laid together and pre-evacuated. After the pre-evacuation, the twisted wire status is checked, and the subsequent side panels are laid according to the twisted wire status. S24: When laying the side layers, place carbon twisted wire strips in the middle circle after closing the mold. The twisted wire needs to be compacted in place. The twisted wire should bulge out a little after filling and compaction. After filling the twisted wire, vacuum for 20 minutes and observe the state of the twisted wire. If the twisted wire is concave, fill it with twisted wire to make it bulge out a little, and then lay the side panels; S25: After the side layers are laid, lay a layer of high-temperature wet peelable cloth. After the upper mold is removed, lay the high-temperature wet peelable cloth on the part belly plate, upper mold belly plate and inner side plate as a whole. The wet peelable cloth needs to be disconnected at the R corner of the part.

[0008] Furthermore, in S3: after the upper and lower molds are closed and before the upper mold is taken out, after the upper and lower mold material sheets are laid, a layer of non-porous film is covered on the surface of the upper mold and the lower mold, the upper mold is flipped 180° by the flipping tool, and the flipping tool is hoisted together with the upper mold using tools, and closed with the lower mold through the guide column, and the non-porous film is removed; after the closing is completed, the screws in the upper mold flipping tool and the upper mold are removed, and the flipping tool is taken out by the tool; when closing the mold, a pressure equalizing plate is placed, and a copper pad with a thickness of 1.0 mm is placed on the pressure equalizing plate to control the thickness.

[0009] Furthermore, in S4: at least two thermocouples are installed on the edge of the part margin, and the thermocouple numbers are recorded in the inspection record page; two vacuum air nozzles are placed at the diagonal positions of the lower mold of the tooling, one for exhaust and one for testing; the vacuum test requires that the vacuum be at least -85kap, and the vacuum drop within 10 minutes is no more than 3kPa. The part can be put into the tank only after passing the vacuum test.

[0010] Furthermore, in S5: S51: Before curing begins, fill in the airtightness inspection record in the layup record sheet; S52: Evacuate 0.09~0.098MPa, heat up to 80±5℃ at a heating rate of less than 3℃ / min, add 0.5±0.03Mpa external pressure when the temperature reaches 80±5℃, close the vacuum and vent to the atmosphere when the pressure reaches 0.1MPa, keep warm and maintain pressure for 10~40min; after the insulation is completed, continue to heat up to 180±5℃ at a heating rate of less than 3℃ / min, when the temperature reaches 180±5℃, keep warm and maintain pressure for 120~300min; after the insulation is completed, cool down to below 60℃ at a cooling rate of less than 3℃ / min, then release the pressure, and when the pressure drops to 0.08~0.15Mpa, open the vacuum and maintain for more than 10min until it is taken out of the tank.

[0011] Further, in S6: remove the pressure block of the part, and then gently remove the equalizing plate; after removing the side pressure blocks and the equalizing plate, use a scraper to clean the glue accumulated in the center block groove, use a copper scraper or a composite wedge to demold the part margin area, and demold the part. Be careful not to damage the part and the tooling surface when demolding.

[0012] Furthermore, in S7: S71: Cutting: Use a pneumatic cutting machine to roughly cut the outer contour of the part along 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 margin left, and retain the cutting line. After passing the inspection, use sandpaper dipped in water to grind away the raised cutting line; S72: Drilling: Use the corresponding drill bit to drill the parts, and finally use a reamer to ream the holes and remove burrs.

[0013] The present invention provides a forming method for composite material ribs, which is used to solve the problem of defects such as pores and white spots appearing on the web surface of a part due to insufficient exhaust of a sheet during compression molding and curing. The present invention mainly changes the compression molding to a method of closing the molds for pre-pressing (pre-compacting) after the upper and lower molds are laid, removes the upper mold after the pre-compacting, and changes the compression molding to bag pressing for bag making. In combination with specific process steps and parameter design / optimization, the present invention can solve the problem of defects such as pores and white spots appearing on the web surface of a part during curing during existing compression molding, thereby improving the molding quality of composite material ribs. DETAILED DESCRIPTION

[0014] In order to make the technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further clearly and completely described in detail below. It can be understood that the specific embodiments described here are only partial embodiments of the present invention, which are only used to explain the present invention, not to limit the present invention.

[0015] All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort shall fall within the scope of protection of the present invention. Furthermore, unless otherwise defined, technical or scientific terms used in the description of the present invention shall have the same meanings as those generally understood by persons of ordinary skill in the art to which the present invention belongs.

[0016] A method for forming a composite material rib, characterized in that it comprises the following steps: S1: tooling preparation; The tooling consists of a lower die assembly, an upper die assembly, a pressure equalizing plate, a pressure block and other components. These components and their components are removed from the tooling, cleaned, and coated with a release agent.

[0017] S2: Laying of parts; S21: Prepare a layup table: Lay out the tiles in the order of the layup table. There are four areas in total: the upper mold, the lower mold, the lower mold between the upper and lower molds before mold closing, and finally the side after mold closing. When laying the layers, the upper and lower molds are laid separately, and the material / sheet is laid from the center of the mold body web to the edge strips on both sides. The laying angle deviation of the fabric is ±5°, and the laying angle deviation of the unidirectional tape is ±3°. Before laying each layer of material, after tearing off the backing paper on one side, the material on that side needs to be inspected to check for excess materials (such as hair, backing paper fragments, isolation film fragments, and all other excess materials other than materials). After the material is laid, after tearing off the backing paper on the other side, the material on the other side needs to be inspected to check for excess materials. If there is any excess material, it needs to be removed from the material in time, and the subsequent laying can only be carried out after the processing is completed.

[0018] S22: First, lay a layer of isolation film on the upper mold surface of the tooling, and then lay the blanks on the isolation film. The isolation film is laid to the thickness control area of ​​the upper mold of the tooling. The first layer of blanks of the upper mold is partially laid to the thickness control area. The subsequent blanks are laid at a distance of 3mm from the thickness control area. Note that the blanks must be laid across the part position line. S23: directly lay the sheet on the lower mold of the tooling, and lay the sheet to 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 the mold closing tooling for pre-pressing for more than 30 minutes, and then pre-evacuation (vacuuming) is performed. During pre-evacuation, the twisted wire is laid together and pre-evacuated. After the pre-evacuation, the twisted wire status is checked, and the subsequent side panels are laid according to the twisted wire status; S24: When laying the side layers, place carbon twisted wire strips in the middle circle after closing the mold. The twisted wire needs to be compacted in place. After filling and compacting, the twisted wire should bulge out a little / partially. After filling the twisted wire, vacuum for 20 minutes and observe the state of the twisted wire. If the twisted wire is concave, fill it with twisted wire to make it bulge out a little bit, and then lay the side panels; S25: After the side layers are laid, lay a layer of high-temperature wet peelable cloth. After the upper mold is removed, lay the high-temperature wet peelable cloth on the part belly plate, upper mold belly plate and inner side plate as a whole. The wet peelable cloth needs to be disconnected at the R corner of the part.

[0019] S3: mold closing pre-pressing; After the upper and lower mold pieces are laid, a layer of non-porous film is covered on the surface of the upper mold and the lower mold. The upper mold is flipped 180 degrees using a flip tool. The flip tool is hoisted together with the upper mold using a tool, and closed with the lower mold through the guide column, and the non-porous film is removed. After closing, the screws in the upper mold flip tool and the upper mold are removed, and the flip tool is taken out using a tool. When closing the mold, place an equalizing plate and a copper pad with a thickness of 1.0mm on the equalizing plate to control the thickness; after the upper and lower molds of the tooling are closed, take out the upper mold and the frame of the upper mold, remove the screws between 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, causing the part to be demolded.

[0020] S4: bag making; After removing the upper mold, install the side pressure plate and pressure block to make the vacuum bag; Among them, at least two thermocouples are installed on the edge of the part margin, and the thermocouple numbers are recorded in the inspection record page; two vacuum air nozzles are placed at the diagonal position of the lower mold of the tooling, one for exhaust and the other for testing; the vacuum test requires the vacuum to be at least -85kap, and the vacuum drop within 10 minutes is no more than 3kPa. The part can be put into the tank only after passing the vacuum test.

[0021] S5: curing; S51: Before curing begins, fill in the airtightness inspection record in the layup record sheet; S52: Vacuum 0.09~0.098MPa, heat to 80±5℃ at a heating rate of less than 3℃ / min (preferably 1.5℃ / min), add 0.5±0.03Mpa external pressure (air couple set temperature is 85℃) when the temperature reaches 80±5℃ (hysteresis couple), close the vacuum and vent to the atmosphere when the pressure reaches 0.1MPa, keep the temperature and pressure for 10~40min (preferably 30min) after the insulation is completed. , continue to heat up to 180±5℃ at a heating rate of less than 3℃ / min (set to 1.5℃ / min). When the temperature reaches 180±5℃, keep warm and maintain pressure for 120~300min (set to 180min). After the insulation is completed, cool down to below 60℃ (set to 50℃) at a cooling rate of less than 3℃ / min (set to 1.5℃ / min), and then relieve the pressure. When the pressure drops to 0.08~0.15Mpa, turn on the vacuum and maintain it for more than 10min until it is taken out of the can.

[0022] S6: demoulding; Remove the pressure block of the part, and then gently remove the pressure plate; After removing the side pressure blocks and the equalizing plate, use a scraper to clean the glue accumulated in the center block groove, use a copper scraper or composite wedge to demould the part margin area, and demould the part. Be careful not to damage the part and the tooling surface when demoulding.

[0023] S7: cutting edge drilling; S71: Cutting: Use a pneumatic cutting machine to roughly cut the outer contour of the part along 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 margin left, and retain the cutting line. After passing the inspection, use sandpaper dipped in water to grind away the raised cutting line; S72: Drilling: Use the corresponding drill bit to drill the parts, and finally use a reamer to ream the holes and remove burrs.

[0024] S8: Inspection; Inspect the shape, size, surface quality, etc. of parts and record the inspection results.

[0025] The present invention provides a forming method for composite material ribs, which is used to solve the problem of defects such as pores and white spots appearing on the web surface of a part due to insufficient exhaust of a sheet during compression molding and curing. The present invention mainly changes the compression molding to a method of closing the molds for pre-pressing (pre-compacting) after the upper and lower molds are laid, removes the upper mold after the pre-compacting, and changes the compression molding to bag pressing for bag making. In combination with specific process steps and parameter design / optimization, the present invention can solve the problem of defects such as pores and white spots appearing on the web surface of a part during curing during existing compression molding, thereby improving the molding quality of composite material ribs.

[0026] The above-mentioned embodiments are illustrative of the present invention, not limiting thereof. It is understood that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for forming a composite material rib, characterized in that: The following steps are involved: S1: tooling preparation, The tooling includes the lower die assembly, upper die assembly, equalizing plate, and pressing block. After cleaning the tooling, apply the release agent evenly. S2: Laying of parts, The upper and lower molds are laid separately, and the material pieces are laid from the center of the mold body web to the edge strips on both sides. The laying angle deviation of the fabric is ±5°, and the laying angle deviation of the unidirectional tape is ±3°; Before laying each layer of material, tear off the backing paper on one side to check for excess material; after laying, tear off the backing paper on the other side to recheck and clean; after finishing, continue laying the layer; S3: mold closing pre-pressing, After the upper and lower molds of the tooling are closed, the upper mold is taken out, the frame of the upper mold is also taken out, the screws between the upper mold and the frame are removed, and the part is separated from the upper mold by lifting tools to achieve demoulding; Among them, after the upper and lower molds of the tooling are closed and before the upper mold is removed, after the upper and lower mold sheets are laid, the surfaces of the upper and lower molds are covered with non-porous film, and the upper mold is flipped 180 degrees by the flip tooling. After hoisting, it is closed with the lower mold through the guide column to remove the non-porous film; after closing, the screws in the upper mold flip tooling and the upper mold are removed, and the flip tooling is taken out by tools; when closing the mold, a pressure plate is placed, and a copper pad with a thickness of 1.0mm is placed on the pressure plate to control the thickness; S4: Bag making, After removing the upper mold, install the side equalizing plates and pressure blocks to make the vacuum bag; Among them, at least two thermocouples are installed on the edge of the part margin, and the thermocouple numbers are recorded; two vacuum air nozzles are placed at the diagonal positions of the lower mold, one for exhaust and the other for testing; the vacuum test requires the vacuum to be at least -85kPa, and the vacuum drop within 10 minutes should not exceed 3kPa. Only qualified ones can be put into the tank; S5: curing; S6: Demolding: remove the pressing block of the part, remove the equalizing plate, clean the glue accumulated in the center block groove, use a copper scraper or composite wedge to demould the part in the margin area, and demould the part to avoid damaging the part and the tooling surface; S7: cutting edge drilling; S8: Inspection.

2. The method for forming a composite material rib according to claim 1, wherein: In S2: S21: Prepare a layup table and lay out the layers in the order listed. There are four areas in total: the upper mold, the lower mold, the lower mold between the upper and lower molds before mold closing, and finally the side after mold closing. S22: First, lay a layer of isolation film on the upper mold surface of the tooling, and then lay the blanks on the isolation film. The isolation film is laid to the thickness control area of ​​the upper mold of the tooling. The first layer of blanks of the upper mold is partially laid to the thickness control area. The subsequent blanks are laid at a distance of 3mm from the thickness control area. Note that the blanks must be laid across the part position line. S23: directly lay the sheet on the lower mold of the tooling, and lay the sheet to 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 the mold closing tooling for pre-pressing for more than 30 minutes, and then pre-vacuuming is performed. During the pre-vacuuming, the twisted wire is laid together and pre-evacuated. After the pre-evacuation, the twisted wire status is checked, and the subsequent side panels are laid according to the twisted wire status. S24: When laying the side layers, place carbon twisted wire strips in the middle circle after closing the mold. The twisted wire needs to be compacted in place. The twisted wire should bulge out a little after filling and compaction. After filling the twisted wire, vacuum for 20 minutes and observe the state of the twisted wire. If the twisted wire is concave, fill it with twisted wire to make it bulge out a little, and then lay the side panels; S25: After the side layers are laid, lay a layer of high-temperature wet peelable cloth. After the upper mold is removed, lay the high-temperature wet peelable cloth on the part belly plate, upper mold belly plate and inner side plate as a whole. The wet peelable cloth needs to be disconnected at the R corner of the part.

3. The method for forming a composite material rib according to claim 1, wherein: In S5: S51: Before curing begins, fill in the airtightness inspection record in the layup record sheet; S52: Evacuate 0.09~0.098MPa, heat up to 80±5℃ at a heating rate of less than 3℃ / min, add 0.5±0.03Mpa external pressure when the temperature reaches 80±5℃, close the vacuum and vent to the atmosphere when the pressure reaches 0.1MPa, keep warm and maintain pressure for 10~40min; after the insulation is completed, continue to heat up to 180±5℃ at a heating rate of less than 3℃ / min, when the temperature reaches 180±5℃, keep warm and maintain pressure for 120~300min; after the insulation is completed, cool down to below 60℃ at a cooling rate of less than 3℃ / min, then release the pressure, and when the pressure drops to 0.08~0.15Mpa, open the vacuum and maintain for more than 10min until it is taken out of the tank.

4. The method for forming a composite material rib according to claim 1, wherein: In S7: S71: Cutting: Use a pneumatic cutting machine to roughly cut the outer contour of the part along 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 margin left, and retain the cutting line. After passing the inspection, use sandpaper dipped in water to grind away the raised cutting line; S72: Drilling: Use the corresponding drill bit to drill the parts, and finally use a reamer to ream the holes and remove burrs.