CN114918306B

CN114918306B - Injection-press forming method and apparatus for metal resin laminated structure

Info

Publication number: CN114918306B
Application number: CN202210600069.2A
Authority: CN
Inventors: 庄新村; 梁美勒; 赵震
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2022-05-27
Filing date: 2022-05-27
Publication date: 2023-03-28
Anticipated expiration: 2042-05-27
Also published as: CN114918306A

Abstract

An injection-press forming method and apparatus for a metal resin laminated structure, injecting fluid resin from one side of a core sandwich of two metal plates to be pressed by applying injection pressure while exhausting gas from the other side to realize injection filling; after the sandwich layer of the core part is filled with resin, further increasing injection pressure, enabling the flowing resin to push the metal plate to generate plastic deformation under the action of the pressure, simultaneously starting a press, driving an upper die to move downwards by utilizing a press sliding block, and finishing the forming step under the combined action of liquid expansion pressure; and finally, performing pressure maintaining and heating curing in the mold to obtain the metal resin laminated structure part with the geometric characteristic structure. The device enables the fluid resin to actively participate in the plastic deformation process of the metal outer layer through the synergistic action of injection pressurization and die stamping action, completes the forming manufacture of the specific metal resin laminated structure part in a single process, can obtain good forming quality, and effectively improves the forming efficiency.

Description

Injection-press forming method and apparatus for metal resin laminated structure

Technical Field

The invention relates to a technology in the field of composite board forming, in particular to an injection-stamping forming method and device for a metal resin laminated structure.

Background

The fabrication of metal resin laminate structural parts is generally accomplished on two types of routes. In the first route, a flat resin is cured and bonded to a metal outer layer by a method such as thermocompression curing, and then a force is applied to the laminate to form the laminate into a desired shape. The method has higher forming efficiency, but the laminated plate has lower forming limit, and the base body is easy to crack and delaminate. In the second route, the metal outer layer and the resin are preformed respectively to make the metal layer and the resin core layer meet the size requirement of a target structure, and then hot-pressing curing bonding is carried out. In the whole manufacturing process, the resin does not participate in the plastic deformation process of the metal outer layer. The introduction of the pre-forming process can avoid the matrix cracking and delamination caused by the large plastic deformation of the metal outer layer, but the production efficiency is greatly reduced, and the equipment cost required by forming is increased.

Disclosure of Invention

The invention provides an injection-stamping forming method and device for a metal resin laminated structure, aiming at the defects in the prior art, the fluid resin actively participates in the plastic deformation process of a metal outer layer through the synergistic action of injection pressurization and die stamping action, the forming and manufacturing of a specific metal resin laminated structure part are completed in a single process, the good forming quality can be obtained, and the forming efficiency is effectively improved.

The invention is realized by the following technical scheme:

the invention relates to an injection-stamping forming method for a metal resin laminated structure, which comprises the steps of injecting fluid resin from one side of a core interlayer of a two-layer metal plate to be stamped by applying injection pressure, exhausting gas from the other side to realize injection filling; after the sandwich layer of the core part is filled with resin, further increasing injection pressure, enabling the flowing resin to push the metal plate to generate plastic deformation under the action of the pressure, simultaneously starting a press, driving an upper die to move downwards by utilizing a press sliding block, and finishing the forming step under the combined action of liquid expansion pressure; and finally, performing pressure maintaining and heating curing in the mold to obtain the metal resin laminated structure part with the geometric characteristic structure.

In the injection filling, in order to ensure good filling and exhausting effects, a smaller initial injection flow rate is preferably adopted, specifically, the flow rate of the unit sectional area is 1-10 mm/s, so that the fluid resin enters the area to be filled at the smaller initial flow rate, and after the fluid resin is spread and fully infiltrated, the injection flow rate can be increased to improve the filling efficiency. In actual production, the specific injection flow rate can be adjusted appropriately according to the filling area size structure and the size of the injection port.

The liquid expansion pressure needs to be adjusted correspondingly at different stages of forming. After the initial filling of the fluid resin is completed, the liquid expansion pressure is preferably increased to 5MPa to ensure that the metal plate is pressed against the edge block under the action of the liquid expansion pressure to realize sealing; then, under the action of liquid expansion pressure, the lower layer metal plate can generate certain deformation and arch to a certain height towards the cavity side of the female die; by increasing the liquid inflation pressure, the arching height can be increased. To the sandwich structure of not laying continuous fiber layer, the liquid pressure that provides should satisfy the complete demand that warp of lower floor's metal sheet, and the increment of liquid pressure that expands should make lower floor's metal sheet after producing certain hunch-up height, avoid taking place to contact with the upper metal sheet that the terrace die effect warp down, and then produce secondary seal chamber, influence the shaping quality of part. For the structure of laying the continuous fiber layer, the lower metal plate completes forming under the combined action of the die forming force and the liquid expansion pressure transmitted by the fiber layer, so that the liquid expansion pressure can be properly reduced, and the phenomenon that the thickness distribution of resin is influenced by the lack of contact between the fiber layer and the lower metal plate is avoided. The regulation and control mode of the liquid expansion pressure needs to be adjusted and optimized according to the structural size, the blank size, the mechanical property of the material and the like of the target part.

The metal resin laminated member is preferably subjected to subsequent curing in an insulation box to obtain better mechanical properties.

The invention relates to an injection-stamping forming device for realizing the method, which comprises the following steps: go up mould part, lower mould part and with lower mould part sealing connection's injecting glue part, wherein: the upper and lower die portions form a stamping system.

The glue injection part comprises: the glue bins are symmetrically arranged on two sides of the lower die part, and the driving cylinders are connected with the glue bins on one side.

The upper die part comprises: cope match-plate pattern, terrace die and the blank pressing piece that sets gradually, wherein: the male die is fixedly connected with the upper die plate, the edge pressing block is movably arranged outside the male die and is in sliding connection with the upper die plate, and the male die and the edge pressing block are opposite to the lower die part.

The lower die part comprises: lower bolster and set up die holder plate, die and material returned mechanism above that, wherein: the female die and the material returning mechanism are sequentially arranged in the female die fixing plate, and two sides of the female die fixing plate are respectively in sealing connection with the glue bin of the glue injection part.

And a heating device is further arranged in the female die to realize the curing operation.

The sealing connection is preferably realized through a glue injection head fixedly arranged in the female die fixing plate.

The material returning mechanism comprises: the stripper plate and set up main ejector pin and follow ejector pin on it.

Technical effects

The invention uses the liquid expansion pressure of the fluid resin to assist the metal plate to be punched and formed, can avoid the matrix fracture and the layering phenomenon in the deformation process of the metal-resin laminated structure, and improves the forming efficiency of metal resin laminated structure parts, including metal resin sandwich structure parts and metal continuous fiber resin reinforced laminated structure parts.

Drawings

FIG. 1 is a schematic view of an injection-press forming apparatus;

FIG. 2 is a schematic view of a female mold structure;

FIG. 3 is a schematic view of the structure of the edge sealing ring;

FIG. 4 is a schematic diagram of the glue injection head;

FIG. 5 is a schematic view of the mold structure at the beginning and end of forming;

FIG. 6 is a flowchart of an example process;

fig. 7 shows the result of forming a6061 aluminum alloy-epoxy resin sandwich structure part under the synergistic effect of liquid expansion pressure and die stamping.

FIG. 8 is a schematic diagram of a fabric blank and a structural member corresponding to different core layer structures;

in the figure: the device comprises an oil cylinder piston 1, a pressure oil cylinder 2, an injection piston 3, a glue bin end cover 4, a first glue bin 5, an upper template 6, a male die fixing plate 7, a male die base plate 8, a male die 9, a blank pressing guide pillar 10, a blank pressing guide pillar limiting block 11, a guide sleeve 12, a guide pillar 13, a blank pressing block 14, a female die fixing plate 15, an outer sealing ring 16, a second glue bin 17, a female die 18, a heating pipe 19, a lower template 20, a discharging plate 21, a main ejector rod 22, a slave ejector rod 23 and a glue injection head 24.

Detailed Description

As shown in fig. 1, the present embodiment relates to an injection-press forming apparatus for a metal-resin laminated structure, including: go up mould part, lower mould part and with lower mould part sealing connection's injecting glue part, wherein: the upper and lower die portions form a stamping system.

The glue injection part specifically comprises: hydro-cylinder piston 1, pressure cylinder 2, injection piston 3, glue storehouse end cover 4, first gluey storehouse 5, second and glue storehouse 17 and injecting glue head 24, wherein: the pressure oil cylinder 2 and the oil cylinder piston 1 provide injection pressure; the pressure oil cylinder 2 is connected with an external hydraulic workstation, can provide stable and adjustable liquid pressure, and transmits the pressure into the first glue bin 5 through the oil cylinder piston 1 to enable fluid resin in the first glue bin to have certain pressure; the second glue bin 17 is used for containing excess fluid resin overflowing in the initial injection stage and playing a role in exhausting air; the first glue bin 5 and the glue bin tightly press and fix the glue injection head 24 in the female die fixing plate 15 through bolts, and the sealing is realized by using an elastic sealing ring at the outer side; elastic sealing rings are adopted between the male die 9 and the edge pressing block 14 and between the edge pressing block 14 and the metal plate for sealing, so that the fluid resin is prevented from leaking.

The upper die part specifically comprises: cope match-plate pattern 6, punch plate 7, terrace die backing plate 8, terrace die 9, blank pressing guide pillar 10, blank pressing guide pillar stopper 11, wherein: the upper template 6 is connected with the upper table surface of the press machine to drive the male die 9 to complete the up-and-down movement, thereby realizing the stamping forming action; the edge pressing block 14 ensures the stability of the edge pressing guide column 10 fixed on the edge pressing block when moving along with the upper die, and realizes the return motion along with the upper die by using the edge pressing guide column limiting block 11.

The lower die part specifically comprises: blank pressing block 14, die fixing plate 15, limit sealing washer 16, die 18, heating pipe 19, lower bolster 20, stripper 21, main ejector pin 22 and follow ejector pin 23, wherein: the edge pressing block 14 is fastened on the female die fixing body 15 through a bolt, and after the fixing bolt is screwed down, the edge sealing ring 16 can be tightly pressed; the side sealing ring 16 is a rotary ring-shaped rigid part, and two sides of the side sealing ring are provided with small holes for flowing of fluid resin; the edge sealing ring 16 ensures that the fluid resin cannot leak out through the locking action with the edge pressing block 14; the heating pipe 19 is used for heating and curing the fluid resin, and after the liquid-solid conversion of the fluid resin is completed, the discharging action is completed through the combined action of the discharging plate 21, the main ejector rod 22 and the auxiliary ejector rod 23.

The punching system is realized by a guide sleeve 12 and a guide post 13 which are arranged between an upper die part and a lower die part.

The edge pressing block 14 is connected with the edge pressing guide pillar 10 and can move upwards along with the upper template through the edge pressing guide pillar limiting block 11.

As shown in fig. 2, a through hole 181 for placing the ejector rod is formed at the bottom end of the cavity of the female die 18 to realize the ejection action; the outside of the female die is provided with a circular groove 182 for placing the elastic sealing ring 25 and the top ring 26 shown in fig. 5.

The bottom of the groove 182 is provided with a through hole 183 which is in clearance fit with the secondary mandril 23, and the front and the rear surfaces are provided with through holes 184 for placing heating pipes.

As shown in fig. 3, the edge sealing rings 16 are used to position and seal the upper and lower metal plates. According to the requirement, the side wall of the central circular hole can be provided with or not provided with a boss, the upper surface 161 and the lower surface 162 of the boss are respectively contacted with the upper metal plate and the lower metal plate, the height of the boss is consistent with the thickness of the core part of the target structure, the central position of the boss structure is provided with a small hole 163 which is communicated with the outer side surface of the side sealing ring, and an injection pipeline is provided for fluid resin to flow.

As shown in fig. 4, the front and

rear end surfaces

241 and 242 of the glue injection head 24 are respectively in contact with the first glue bin 5 and the side sealing ring 16, the central through hole 244 is a flow passage of fluid resin, and connects the first glue bin 5, the second glue bin 17 and the side sealing ring 16, and the side surface 243 is in contact with the elastic sealing ring, so as to ensure the sealing performance.

The oil cylinder 2 is connected with the hydraulic station, can move rightwards by controlling the oil cylinder piston 1 and is transferred to fluid resin by the injection piston 3; the flow rate and pressure of the fluid resin can be controlled by the regulation of the hydraulic station.

In the stamping system, the forming of structural parts with different sizes can be adapted by adjusting the cavity structures of the male die 9 and the female die 18. By changing the mode of stacking the metal plates and the structure of the edge sealing ring 16, the forming of metal resin laminated structures under different material thickness ratios and different laminating modes can be adapted.

A6061 aluminum alloy-epoxy resin sandwich structure flanged cylindrical structural member is taken as an implementation case. Fig. 5 is a schematic view of the mold structure at the beginning and end of the forming process, and fig. 6 is a complete process flow.

At the beginning of forming, A6061-T6 aluminum alloy round blanks with the diameter of 90mm and the thickness of 0.5mm are placed on the upper side and the lower side of the edge sealing ring 16, and the fastening and the connection of each structural part are completed according to the graph 1. And opening a glue injection port above the first glue bin 5, injecting the fully mixed epoxy resin-curing agent mixed fluid into the cavity, and closing the glue injection port after the cavity is filled with the fully mixed epoxy resin-curing agent mixed fluid. And starting the oil cylinder 2, controlling the external hydraulic station to enable the oil cylinder piston 1 to slowly push the injection piston 3 rightward, enabling the resin fluid to sequentially flow through the left glue injection head 24 and the side sealing ring 16 on the left side, flowing to a sandwich cavity formed by surrounding of the upper metal plate 27-2 and the lower metal plate 27-1 at a flow speed of not more than 10mm/s, and after the infiltration and filling of the sandwich cavity are completed, flowing through the second glue bin 17 through the right glue injection head 24. The air in the cavity is extruded by the fluid resin in the process and is exhausted through the air outlet above the second glue bin 17. After the second glue bin 17 is completely filled, the exhaust port above the second glue bin is closed immediately, and the whole runner system is sealed.

After the sealing of the flow channel system is completed, the liquid expansion pressure is gradually increased to 5MPa as shown in fig. 7 to improve the sealing of the fluid in the flow channel. At first, the material pushing ring 26 is slightly higher than the outer plane of the female die 18 under the support of the elastic sealing ring 25, and at the moment, the elastic sealing ring 25 is compressed under the action of downward pressure, so that the material pushing ring 26 is flush with the outer side of the female die, a certain pressing force is provided for the lower-layer metal plate 27-1, and the sealing performance is ensured. Similarly, when the liquid pressure rises, the upper layer metal plate 27-2 is pressed against the bead block 14, and also the sealability is ensured. Meanwhile, under the liquid expansion pressure of 5MPa, the lower layer metal plate 27-1 is arched by about 13.6mm towards the cavity of the female die, the upper layer metal plate 27-2 is arched by about 0.63mm upwards at the fillet clearance position of the male die, and fluid resin required by the arched position is supplied by the first rubber bin 5.

And starting the male die, and descending at the speed of 0.5mm/s to perform stamping forming action, wherein the stroke of the male die is 16mm. Meanwhile, the liquid expansion pressure is further increased and linearly increased from 5MPa to 12MPa in the full stroke. In the whole forming process, the upper layer metal plate 27-2 and the lower layer metal plate 27-1 are not contacted all the time, and no secondary sealing cavity is formed; the maximum plastic strain corresponding to the upper layer A6061-T6 aluminum alloy plate and the lower layer A6061-T6 aluminum alloy plate is respectively 0.30 and 0.27, the phenomena of cracking and wrinkling are not generated, and the forming quality is good.

After the male die finishes the whole stroke, the resin between the upper layer metal plate and the lower layer metal plate is still in a fluid state, in order to prevent the upper layer metal plate and the lower layer metal plate from generating elastic recovery, 12MPa of liquid expansion pressure is still applied for pressure maintaining, meanwhile, the heating pipe 19 is electrified, the temperature is increased to 120 ℃, then the die is continuously heated, and the core resin is heated to complete liquid-solid conversion. And (3) preserving the heat for 20min, and loosening the connecting bolt between the edge pressing block 14 and the female die protective body 15 after the resin is primarily cured so as to enable the edge pressing block to move upwards along with the upper die. The stripper plate 21 is pushed to move the main ram 22 and the slave ram 23 upward synchronously, thereby completing the unloading operation of the formed piece. In order to obtain satisfactory interlayer adhesion and resin mechanical properties, the formed article is preferably placed in an incubator and heated to a certain temperature to achieve complete curing.

In addition, short fibers can be added into the resin fluid, and a corresponding short fiber reinforced metal-resin sandwich structural member can be obtained; when the continuous fiber layer is laid between the metal blank layers and the structure of the side seal ring 16 is appropriately adjusted, the above-described procedure is repeated, whereby a metal fiber reinforced resin laminated member having a core portion of the continuous fiber reinforced resin layer as shown in fig. 8 can be obtained.

Compared with the prior art, the invention effectively shortens the forming manufacturing process route of the metal resin laminated structure part, ensures the forming quality of the part and does not have the phenomena of matrix fracture and delamination; 2) The resin matrix is used as the flexible medium Shi Jiaye expansion pressure, so that the surface pollution possibly generated in the preforming process of a metal and resin bonding interface is avoided, the air exhaust effect in a liquid cavity is promoted in a pressurizing mode, and the good interlayer interface performance between the metal and the resin matrix is ensured.

The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. An injection-press forming method for a metal resin laminated structure is characterized in that injection filling is performed by applying injection pressure to inject fluid resin from one side of a core sandwich of two metal plates to be pressed while exhausting gas from the other side; after the sandwich layer of the core part is filled with resin, further increasing injection pressure, enabling the flowing resin to push the metal plate to generate plastic deformation under the action of the pressure, simultaneously starting a press, driving an upper die to move downwards by utilizing a press sliding block, and finishing the forming step under the combined action of liquid expansion pressure; and finally, performing pressure maintaining and heating curing in the mold to obtain the metal resin laminated structure part with the geometric characteristic structure.

2. The injection-press forming method for a metal-resin laminated structure according to claim 1, wherein the injection filling is performed by using a small initial injection flow rate, specifically, a flow rate per unit cross-sectional area is 1 to 10mm/s, so that the fluid resin enters the region to be filled at the small initial flow rate, and after the fluid resin is spread and sufficiently infiltrated, the injection flow rate can be increased to improve the filling efficiency.

3. An injection-press forming method for a metal-resin laminated structure according to claim 1, wherein said liquid-expansion pressure is raised to 5MPa after the preliminary filling of the fluid resin is completed, to ensure that the metal plate is pressed against the edge block by the liquid-expansion pressure to achieve sealing.

4. An injection-press forming apparatus for carrying out the method of any one of claims 1~3 comprising: go up mould part, lower mould part and with lower mould part sealing connection's injecting glue part, wherein: the upper die part and the lower die part form a stamping system;

the glue injection part comprises: the glue bins are symmetrically arranged at two sides of the lower die part, and the driving cylinders are connected with the glue bins at one side;

the upper die part comprises: cope match-plate pattern, terrace die and the blank pressing piece that sets gradually, wherein: the male die is fixedly connected with the upper die plate, the edge pressing block is movably arranged outside the male die and is in sliding connection with the upper die plate, and the male die and the edge pressing block are opposite to the lower die part;

the lower die part comprises: lower bolster and set up die fixing plate, die and material returned mechanism above that, wherein: the female die and the material returning mechanism are sequentially arranged in the female die fixing plate, and two sides of the female die fixing plate are respectively in sealing connection with the glue bin of the glue injection part.

5. The injection-press forming apparatus as claimed in claim 4, wherein a heating means is further provided in said cavity die for performing a curing operation.

6. An injection-press forming apparatus as claimed in claim 4, wherein said sealing engagement is provided by a compound injection head fixedly disposed within the cavity retaining plate.

7. The injection-press forming apparatus of claim 4, wherein said material return mechanism comprises: the stripper plate and the main ejector rod and the auxiliary ejector rod which are arranged on the stripper plate.

8. The injection-press forming apparatus of claim 4~7 wherein said glue injection portion comprises: hydro-cylinder piston, pressure cylinder, injection piston, glue storehouse end cover, first storehouse, the second of gluing and injecting glue head, wherein: the pressure oil cylinder and the oil cylinder piston provide injection pressure; the pressure oil cylinder is connected with an external hydraulic workstation, can provide stable and adjustable liquid pressure, and transmits the pressure into the first glue bin through the oil cylinder piston to enable fluid resin in the first glue bin to have pressure; the second glue bin is used for containing excess fluid resin overflowing in the initial injection stage and playing a role in exhausting air; the first glue bin and the second glue bin tightly press and fix the glue injection head in the female die fixing plate through bolts, and the sealing is realized by using an elastic sealing ring at the outer side; elastic sealing rings are adopted between the male die and the edge pressing block and between the edge pressing block and the metal plate for sealing, so that the fluid resin is prevented from leaking.

9. The injection-press forming device of claim 4~7 wherein said upper mold portion comprises: cope match-plate pattern, punch plate, terrace die backing plate, terrace die, blank pressing guide pillar stopper, wherein: the upper template is connected with the upper table-board of the press machine to drive the male die to complete up-and-down movement, so as to realize the stamping forming action; the edge pressing block guarantees the stability of the edge pressing block when the edge pressing block moves along with the upper die through the edge pressing guide pillar fixed on the edge pressing block, and the edge pressing guide pillar limiting block is used for realizing the return movement of the edge pressing block along with the upper die.