CN-121989476-A - Runner system, mold and molding method for RTM molding of spherical shell composite material

CN121989476ACN 121989476 ACN121989476 ACN 121989476ACN-121989476-A

Abstract

The invention discloses a runner system, a mold and a molding method for RTM molding of a spherical shell composite material. The runner system is arranged between the upper die and the lower die and comprises a sector glue inlet and a glue outlet at the upper extreme point and the lower extreme point which are circumferentially and uniformly distributed in the equatorial region, so that resin is uniformly filled and high-efficiency air exhaust is realized. The forming die takes the runner system as a core, integrates an upper die, a lower die, an external die opening tool and a multi-piece metal mandrel, and has the functions of accurate positioning, reliable sealing and intelligent die opening. The molding method sequentially comprises the steps of mandrel assembly and positioning, die assembly and sealing, resin infusion and solidification, intelligent die opening, manual die stripping and the like. The invention has the advantages of standard flow and controllable operation, effectively solves the problems of uneven filling, unsmooth air exhaust, difficult die opening, easy damage in demolding and the like in the traditional molding, improves the molding precision, the production efficiency and the product quality, and is suitable for RTM molding of large spherical shells.

Inventors

YUAN LING
WAN JUN
LI HAOLIANG
SHA HUIPING

Assignees

上海伽材新材料科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260212

Claims (15)

1. A runner system for RTM molding of spherical shell composite material disposed between an upper die and a lower die of a spherical shell mold, comprising: a plurality of glue inlets are uniformly distributed along the circumferential direction of the parting surface of the upper die and the lower die, and all the glue inlets are positioned in the equatorial region of the spherical shell; A first glue outlet is arranged at the highest point of the top of the cavity of the upper die and A second glue outlet is formed in the lowest point of the bottom of the cavity of the lower die; The first glue outlet and the second glue outlet are matched with the glue inlet in a layout manner, so that resin is symmetrically filled from an equatorial region to the spherical top and the spherical bottom of the spherical shell in a two-way manner, and gas in a cavity of the die is converged to the first glue outlet and the second glue outlet along the flowing direction of the resin and is discharged.
2. The runner system for RTM molding of spherical shell composite material according to claim 1, wherein the number of the glue inlets is 4 to 8, and the glue inlets are equally angularly spaced on the parting surface.
3. The runner system for RTM molding of spherical shell composite material according to claim 1, wherein the glue inlet is a fan gate having a width extending in a circumferential direction of the parting surface.
4. A spherical shell composite material RTM forming die, which is characterized by comprising an upper die, a lower die, a runner system as claimed in claims 1-3 and a set of external die opening tools; The external die sinking tool includes: the lower end of the workpiece supporting rod is detachably and fixedly connected with the upper die or the die inner member; at least two power jacking devices; And at least two support structures arranged outside the lower die and corresponding to the positions of the workpiece support rods; Wherein, each power jacking device is connected between the work piece bracing piece and a corresponding one of the supporting structures.
5. The RTM molding die of spherical shell composite material of claim 4, wherein the workpiece support bar is a square cross-section rigid bar.
6. The RTM molding die for spherical shell composite material according to claim 4, wherein the power jacking device is a hydraulic jack, a pneumatic cylinder, an electric push rod or a screw jacking mechanism.
7. The RTM molding die of spherical shell composite material of claim 4, wherein the power jacking device is integrated with a pressure sensor and is communicatively connected to a controller configured to control a die opening process based on signals from the pressure sensor.
8. The RTM molding die of spherical shell composite material according to claim 4, wherein the support structure is a support fixedly arranged outside the lower die or is a reinforcing rib or boss outside the lower die.
9. The RTM forming die for the spherical shell composite material is characterized by further comprising a multi-piece metal mandrel, wherein the multi-piece metal mandrel comprises a plurality of mandrel segments and mandrel positioning pieces, the mandrel segments are coaxially spliced around the mandrel positioning pieces, positioning structures are arranged between the upper end and the lower end of the mandrel positioning pieces and the mandrel segments, and positioning parts extending downwards are arranged at the bottoms of the mandrel positioning pieces and are used for being matched with corresponding structures at the bottoms of cavities of the lower die.
10. The RTM molding die of spherical shell composite material of claim 9, wherein the positioning structure is a chamfer, taper pin, dovetail groove, T-shaped structure.
11. The RTM molding die for spherical shell composite materials according to claim 9, wherein the matching manner of the positioning portion and the corresponding structure is matching of a positioning hole and a positioning column, matching of a positioning pin and a pin hole, matching of a V-shaped block and a V-shaped groove, or spigot positioning.
12. A method of RTM forming of spherical shell composite materials, characterized in that a mould according to any one of claims 4 to 11 is used, and in turn comprises the following steps: (S1) stitching a plurality of mandrel segments around the mandrel locator to assemble a multi-segment metal mandrel; (S2) the assembled multi-petal metal mandrel is positioned and installed in the cavity of the lower die through the matching of the positioning part at the bottom of the mandrel positioning piece and the bottom of the cavity of the lower die; (S3) combining an upper die on the lower die and locking; (S4) closing the cover plate on the top of the upper die and locking the cover plate; (S5) injecting resin into the die cavity through a plurality of glue inlets circumferentially and uniformly distributed on the parting surface, and simultaneously exhausting gas through a first glue outlet on the cover plate and a second glue outlet at the bottom of the lower die until the resin is full and solidified; (S6) opening and taking out the cover plate, and ejecting and separating the upper die from the lower die by using the external die opening tool; (S7) the external mold opening tool takes out the multi-flap metal mandrel with the cured product from the cavity of the lower mold; (S8) sequentially disassembling and taking out mandrel segments forming the multi-segment metal mandrel, so that the spherical shell product is completely demolded.
13. A method of RTM molding a spherical shell composite according to claim 12, characterized in that in step (S5), resin is injected simultaneously in a linear flow from 4 or 8 glue inlets located in the equatorial region of the spherical shell.
14. The RTM molding method of spherical shell composite material according to claim 12, wherein in step (S6), the specific step of mold opening using the external mold opening tool includes connecting the workpiece support bar with an upper mold, and placing each of the power jacking devices between the workpiece support bar and the corresponding support structure and driving to jack up the upper mold.
15. The RTM molding method of spherical shell composite material according to claim 12, wherein in step (S7), the step of taking out the multi-piece metal mandrel using the external mold opening tool comprises taking out the mandrel by connecting a workpiece support rod thereof with the mandrel positioning member or mandrel segment and driving a power jack.

Description

Runner system, mold and molding method for RTM molding of spherical shell composite material Technical Field The invention belongs to the technical field of composite material forming tools and processes, and particularly relates to an RTM forming runner system, a matched forming die and a forming method for a spherical shell composite material, which are suitable for mass production of spherical composite material products requiring high precision and high consistency. Background The spherical shell composite material is widely applied to the key fields of aerospace, high-end equipment and the like by virtue of the outstanding advantages of high strength and light weight, and an RTM (resin transfer molding) forming process is taken as a core manufacturing mode of the spherical shell composite material, so that the spherical shell composite material has become the mainstream choice of industry. However, in the RTM forming practice of the spherical shell, the prior art still faces a plurality of key technical bottlenecks, and the improvement of product quality and production efficiency is severely restricted. In the aspect of runner system design, traditional scheme adopts single glue inlet or asymmetric glue inlet overall arrangement for the filling speed of resin in spherical die cavity presents obvious inequality, not only causes the problem of local lack of glue, fibre infiltration inadequately easily, still because of gas exhaust route design is unreasonable, leads to remaining a large amount of bubbles in the die cavity. These defects can directly damage the internal structural integrity of the article, severely affecting its mechanical stability, and ultimately leading to production yields at low levels for long periods of time. The existing mold opening tool is mostly of a simple mechanical configuration, lacks of a precise force control adjustment mechanism, is uneven in stress distribution in the mold opening process, is extremely easy to cause mold deformation or surface scratch and damage of molded products, and meanwhile, the mold opening operation is highly dependent on manual experience judgment, so that the operation efficiency is low, consistency in the batch production process is difficult to ensure, and the actual requirement of large-scale production cannot be met. As a core inner supporting member for forming the spherical shell, the positioning accuracy and the demolding convenience of the mandrel directly influence the product quality. The traditional integral type core shaft is easy to adhere to the inner wall of a product in the demolding process, the surface precision of the product is easily damaged by forced stripping, the rejection rate is increased, and the splicing precision of a part of multi-flap type core shaft is difficult to ensure due to the lack of a reliable positioning limiting structure, so that the size deviation of a spherical shell after molding is larger, and the consistency of the product cannot meet the severe requirements of the high-end field. More importantly, the prior art fails to realize deep coordination of runner layout, mold opening tools, mandrel structures and molding processes, and each link is in a fragmented design and independent operation state, so that the continuity and the coordination of the whole production flow are insufficient, and a high-efficiency and accurate mass production system cannot be formed. The current situation makes the prior art difficult to meet the severe requirements of the high-end field on the dimensional precision, mechanical property and production stability of spherical composite material products, so that development of an integrated and high-precision RTM molding integral solution, systematic cracking of core pain points such as uneven runner filling, poor mold opening controllability, insufficient mandrel positioning precision, weak process cooperativity and the like, has become an urgent requirement for industry development. Disclosure of Invention The invention aims to overcome the defects in the prior art, and provides a runner system for RTM (real time kinematic) forming of a spherical shell composite material, which is arranged between an upper die and a lower die of a spherical shell die and is characterized by comprising the following components: a plurality of glue inlets are uniformly distributed along the circumferential direction of the parting surface of the upper die and the lower die, and all the glue inlets are positioned in the equatorial region of the spherical shell; A first glue outlet is arranged at the highest point of the top of the cavity of the upper die and A second glue outlet is formed in the lowest point of the bottom of the cavity of the lower die; The first glue outlet and the second glue outlet are matched with the glue inlet in a layout manner, so that resin is symmetrically filled from an equatorial region to the spherical top and the spherical bottom of the spherical shell in a tw