CN110920096A - Compression molding process of carbon fiber reinforced composite material - Google Patents

Compression molding process of carbon fiber reinforced composite material Download PDF

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Publication number
CN110920096A
CN110920096A CN201911015705.XA CN201911015705A CN110920096A CN 110920096 A CN110920096 A CN 110920096A CN 201911015705 A CN201911015705 A CN 201911015705A CN 110920096 A CN110920096 A CN 110920096A
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China
Prior art keywords
adaptive
carbon fiber
self
pressure head
composite material
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CN201911015705.XA
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Chinese (zh)
Inventor
武晋
胡海朝
谢久明
毕彦
王占辉
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Tianjin Sino German University of Applied Sciences
Tianjin Sino German Vocational Technical College
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Tianjin Sino German Vocational Technical College
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Priority to CN201911015705.XA priority Critical patent/CN110920096A/en
Publication of CN110920096A publication Critical patent/CN110920096A/en
Priority to AU2020100834A priority patent/AU2020100834A4/en
Pending legal-status Critical Current

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28Shaping operations therefor
    • B29C70/30Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
    • B29C70/34Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/02Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/16Cooling
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28Shaping operations therefor
    • B29C70/54Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C2035/0211Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould resistance heating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/16Cooling
    • B29C2035/1658Cooling using gas
    • B29C2035/1666Cooling using gas dried air

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Thermal Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Moulding By Coating Moulds (AREA)

Abstract

The invention provides a compression molding process of a carbon fiber reinforced composite material, which is characterized in that a self-adaptive molding action is innovatively adopted in the processing process of the carbon fiber reinforced composite material, so that a pressure head of an upper die can perform corresponding actions in a self-adaptive manner on the surface of a blank while the carbon fiber reinforced composite material blank is molded, the pressure head can be dynamically adjusted in the whole molding process to adapt to the surface of the blank which is continuously changed, the stress in a carbon fiber cloth layer after the actions is fully absorbed, and aluminum liquid between the carbon fiber cloth layers is fully and uniformly impregnated, so that the mechanical property of the carbon fiber reinforced composite material after the model is molded is remarkably improved.

Description

Compression molding process of carbon fiber reinforced composite material
Technical Field
The invention relates to the field of composite material molding, in particular to a compression molding process of a carbon fiber reinforced composite material.
Background
The carbon fiber reinforced composite material as a novel composite material has the advantages of low specific gravity, high strength, high tensile elastic modulus, small thermal expansion coefficient, good vibration resistance and vibration absorption performance and the like, so that the carbon fiber reinforced composite material is a hotspot of research of people. The forming process of the carbon fiber reinforced composite material has a crucial influence on the performance of the carbon fiber reinforced composite material, a model forming mode is generally adopted in the forming process of the carbon fiber reinforced composite material in the prior art, however, the forming process in the prior art focuses on temperature and a closed environment, no special requirement is required on pressure in a compression molding process, the carbon fiber reinforced composite material can be subjected to compression molding only, if the size of the processed carbon fiber reinforced composite material is small, the influence of the compression molding pressure is small, and if the large carbon fiber reinforced composite material is subjected to compression molding, the compression molding pressure plays a crucial role in the performance of the carbon fiber reinforced composite material. For example, patent document 1 discloses a method for preparing a carbon fiber reinforced aluminum-based layered composite board, which also uses a compression molding process, and uses a vibration workbench in the molding process, so that aluminum liquid wets carbon fibers by vibration, although the process can enable the surfaces of the carbon fibers not to form brittle compounds and the organization structure to be more compact, the structure is more complex due to the addition of the vibration workbench, meanwhile, the impregnated carbon fibers may generate more bubbles inside the carbon fibers due to the influence of the vibration workbench, and the vibration may also cause the carbon fiber cloth layer to generate wrinkles, further affecting the mechanical properties of the carbon fiber composite material; as another example, patent document 2 discloses a carbon fiber composite material vacuum compression molding apparatus, which adds a vacuum pumping device to impregnate a carbon fiber material in a mold under the action of negative pressure, and at the same time, three speeds are used to control the pressurization speed, but the vacuum negative pressure is limited, and although the slow contact can improve the impregnation of resin and carbon fiber in the carbon fiber composite material to a certain extent, the improvement degree is limited, and the stress in the carbon fiber composite material cannot be released; as another example, patent document 3 discloses a multipoint forming method for an aluminum alloy airplane integral panel, in which an upper mold and a lower mold both adopt a multipoint mold structure, and the multipoint molds are adapted to manufacture curved aluminum alloy panels with complicated shapes, but the molds are not linked; as another example, patent document 4 discloses a clamping device with a flexible surface with variable rigidity, which uses a plurality of piston cylinders connected to a magnetorheological valve in common, and the plurality of piston cylinders move to adapt to different surfaces for clamping by switching on and off the magnetorheological valve, but in the clamping device, each piston cylinder is independent and cannot be linked with each other, and the clamping device can only adapt to different flexible surfaces, and does not need to actively apply external force to the flexible surfaces to change the flexible surfaces.
[ patent document 1] CN103397284A
[ patent document 2] CN105034410A
[ patent document 3] CN104646475B
[ patent document 4] CN1799784A
In summary, in the prior art, a compression molding process capable of performing a self-adaptive compression molding action based on the surface shape characteristics of a carbon fiber reinforced composite material, eliminating the internal stress of the carbon fiber reinforced composite material, and performing an active compression molding action to improve the molding characteristics of the carbon fiber reinforced composite material is not provided.
Disclosure of Invention
In order to overcome the defects of the existing compression molding process, the invention provides a technical scheme, and the compression molding process of the carbon fiber reinforced composite material comprises the following steps:
firstly, placing a blank:
placing the blank into a lower die cavity of a lower die of a hot-pressing forming device according to the alternating sequence of the carbon fiber cloth layer, the aluminum powder layer and the carbon fiber cloth layer;
(II) half-closing the mould:
driving a mould pressing cylinder of the hot-press forming device to act, so that a pressure head of an upper mould quickly reaches a lower mould cavity and is in contact with the lower mould cavity to form a semi-closed mould state;
(III) semi-molding environment treatment:
starting a vacuum pump to suck vacuum in the space in the lower die cavity, starting a pressure head and a heating resistance wire A and a heating resistance wire B in the lower die to heat at the same time, turning off the vacuum pump after the negative pressure in the lower die cavity reaches a certain value, and simultaneously continuing heating the heating resistance wire A and the heating resistance wire B until the melting temperature of the aluminum powder reaches 660 +/-3 ℃;
(IV) continuously closing the mold:
starting the die pressing cylinder again to act, so that the pressing head continues to descend, and closing the die pressing cylinder when the pressing head contacts the highest point H of deformation of the blank;
(V) self-adaptive molding action:
starting a balancing rod to extend out to drive a pressure head to continuously and slowly descend, cutting off the connection with a hydraulic pump by 4 self-adaptive telescopic cylinders uniformly arranged on the periphery of the balancing rod, communicating oil passages between rodless cavities of the self-adaptive telescopic cylinders to form a dynamic balance oil cylinder group, enabling the pressure head freely rotating around the balancing rod to be controlled by the dynamic balance oil cylinder group to act, when the pressure head touches the highest point H of deformation of a blank, the blank at the position H can generate a barrier force on the self-adaptive telescopic cylinder at the position, so that hydraulic oil in the self-adaptive oil cylinder is extruded into other 3 self-adaptive telescopic cylinders through a communication pipeline, and when the oil is pressed into the other 3 self-adaptive telescopic cylinders, the oil can generate a back pressure force on the blank at the position, so that redundant aluminum liquid can be extruded to other places; the balancing rod slowly compresses tightly the action and combines the action of a balancing oil cylinder group formed by four communicated self-adaptive oil cylinders to jointly act on the pressure head, further act on the blank and perform self-adaptive molding action on the blank.
(VI) adjusting the levelness of the pressure head of the upper die:
after the self-adaptive molding action is finished, stopping the balance rod from continuously extending out, enabling the electromagnetic valves between the adaptive telescopic cylinders to act, cutting off the communication between the adaptive telescopic cylinders, and then selectively filling liquid into the corresponding self-adaptive oil cylinder according to the state of the pressure head detected by a level gauge arranged at the upper end of the pressure head, so as to adjust the levelness of the pressure head until the levelness detected by the level gauge reaches the standard stopping action, and continuously keeping for 60 seconds;
(VII) cooling:
after the time is reached, the mould pressing cylinder is driven to shrink, the driving pressure head moves upwards, when the lower surface of the pressure head is positioned between the cold air pipe and the vacuum pipe, cold air output from the cold air pipe is rapidly cooled, and the temperature is stopped to be cooled after reaching 60 ℃.
(eighth), taking out the blank:
and taking out the carbon fiber reinforced composite material subjected to compression molding forming to obtain the processed carbon fiber composite material.
Preferably, the certain value in the step (three) is that the vacuum degree in the lower die cavity is below 1 KPa.
Preferably, in the step (five), while the balance rod is slowly molded, a balance cylinder group formed by 4 communicated adaptive cylinders is always subjected to adaptive adjustment of the press head, and the structural design of the balance cylinder group can also absorb the stress inside the blank.
Preferably, in step (five), when the balance bar stretching action is started to drive the ram to continue to descend slowly, the speed of the balance bar satisfies the following conditions: the oil hydraulic pressure in the balancing rod reaches 10MPa, and the whole adaptive molding action process lasts for more than 60 s.
Preferably, a hot press molding apparatus in a compression molding process of a carbon fiber reinforced composite material includes: the device comprises a base, a guide rod, an upper frame, a die pressing cylinder, an upper die and a lower die, wherein the guide rod is fixedly connected between the base and the upper frame, the upper die is arranged on the guide rod in a sliding manner, the die pressing cylinder is connected between the upper die and the upper frame and used for driving the upper die to slide up and down along the guide rod, the lower die is fixedly arranged on the base, the middle part of the lower die is provided with a lower die cavity, the upper die comprises a sliding valve seat and an adaptive pressure head assembly, the sliding valve seat is arranged on the guide rod in a penetrating manner, the adaptive pressure head assembly comprises a balancing rod, an adaptive telescopic cylinder and a pressure head, the upper ends of the balancing rod and the adaptive cylinder are fixedly connected to the lower end of the sliding valve seat, the lower ends of the balancing rod and the adaptive cylinder are rotatably connected to the upper end of the pressure head, the pressure head is of a rectangular structure, the balancing rod is, the four self-adaptive oil cylinders are mutually communicated through pipelines, the balancing rod is also of a telescopic cylinder structure and is used for driving a pressure head to carry out compression molding on the carbon fiber reinforced composite material, during the compression molding, the four communicated self-adaptive oil cylinders form a dynamic balance oil cylinder group to act, and during the compression molding, the self-adaptive compression action is formed by the active compression action of the balancing rod and the action of the dynamic balance oil cylinder group.
Preferably, the dynamic balance cylinder group is adaptive to the surface of the carbon fiber reinforced composite material to enable the pressure head to perform dynamic balance adjustment, so that aluminum liquid which is unevenly distributed in the carbon fiber cloth layer is evenly distributed during compression molding, and the dipping effect of the carbon fiber cloth layer is further improved.
Preferably, the impregnation effect of the carbon fiber cloth layer is improved, the dynamic balance cylinder group can absorb the stress in the carbon fiber cloth layer, the mechanical property of the carbon fiber reinforced composite material is further improved, and the die pressing and the impregnation process are synchronously performed.
Preferably, after the balance rod completes the die pressing process, the communicated oil way between the self-adaptive oil cylinders is closed, and the self-adaptive oil cylinders are filled with liquid through the hydraulic pump, so that the pressure head is kept horizontal, and the flatness of the upper surface of the carbon fiber reinforced composite material is ensured.
Preferably, the balance rod, the self-adaptive telescopic cylinder and the pressure head are respectively connected in a rotating mode through the hinge ball head A and the hinge ball head B.
Preferably, be provided with heating resistor silk B in the bed die, be provided with heating resistor silk A in the pressure head, the lower extreme that lies in heating resistor silk B in the bed die is provided with insulating layer B, is provided with insulating layer A at the back of pressure head, and heating resistor silk A and heating resistor silk B are the helix type structure to make the temperature rise in last mould and the pressure head even.
Preferably, a vacuum pipe is arranged in the lower die cavity and is used for being communicated with a vacuum pump, and in order to rapidly cool the carbon fiber composite material, a cold air pipe is arranged in the lower die cavity and outputs cold air.
Preferably, the vacuum pipe is located at the upper end of the lower mold cavity, the cold air pipe is located at the lower end of the vacuum pipe, and when the pressed carbon fiber composite material needs to be cooled, the pressure head is lifted up, so that the pressure head is located between the vacuum pipe and the cold air pipe, cold air is released, and rapid cooling is performed.
Preferably, in order to guarantee that the lower die cavity can form a sealed space, the periphery of the pressure head is provided with a sealing plug structure, and the pressure head can guarantee that the lower die cavity can form a sealed space in the process of micro-rotation.
Preferably, the hydraulic oil circuit system in the sliding valve seat comprises an oil tank, a hydraulic pump and two-position two-way electromagnetic valves, the hydraulic pump is respectively connected with a balancing rod and a rod cavity of the self-adaptive telescopic cylinder through oil inlet pipelines, the hydraulic pump is communicated with the balancing rod and the self-adaptive telescopic cylinder through the oil inlet pipelines, the two-position two-way electromagnetic valves are arranged on each oil inlet pipeline, four self-adaptive telescopic cylinders are respectively a first self-adaptive telescopic cylinder, a second self-adaptive telescopic cylinder, a third self-adaptive telescopic cylinder and a fourth self-adaptive telescopic cylinder, the first self-adaptive telescopic cylinder and the second self-adaptive telescopic cylinder are respectively communicated with each other through a communication pipeline, the third self-adaptive telescopic cylinder and the fourth self-adaptive telescopic cylinder are respectively communicated with each other through a communication pipeline, and the two-position two-way electromagnetic valves are respectively arranged on the communication pipelines, the balance rod oil inlet cavity is communicated with an oil tank through an oil return pipeline, a two-position two-way electromagnetic valve is arranged on the oil return pipeline, rod cavities of the first self-adaptive telescopic oil cylinder, the second self-adaptive telescopic oil cylinder, the third self-adaptive telescopic oil cylinder and the fourth self-adaptive telescopic oil cylinder are communicated with the oil tank through another oil return pipeline, and a two-position two-way electromagnetic valve is arranged on the other oil return pipeline bus.
Preferably, in order to be able to adjust the resetting of the respective adaptive telescopic oil cylinders, a resetting spring is sleeved in the rod cavity.
Preferably, a level detector is installed at an upper portion of the indenter in order to detect the position of the indenter.
The invention has the beneficial effects that:
1) in the compression molding process, considering that the carbon fiber reinforced composite material is an aluminum powder layer and carbon fiber cloth layers which are alternately laminated, in order to ensure the connection strength between the layers and ensure that aluminum powder can be soaked to each corner of the carbon fiber cloth layers under the condition of being converted into aluminum liquid so as to ensure uniform soaking, the upper film is arranged to be a structure in which the middle is hinged on the sliding valve seat through the balance rod and the periphery is uniformly provided with the self-adaptive telescopic oil cylinders capable of linking, through the structural arrangement, when the compression molding is carried out, the compression molding cylinder drives the upper film to descend, the pressure head at the lower end of the upper die can freely rotate around the balance rod, when the upper die contacts the composite material to be compressed, the compression molding cylinder stops acting, the pressure head can adapt to the shape of the upper surface of the composite material to generate relative rotation, if the amount of aluminum liquid in the composite, the upper surface of the composite material of the part bulges, the pressure head firstly contacts the surface of the composite material of the part, the adaptive telescopic cylinder corresponding to the upper end of the part is stressed and contracted, the oil liquid in the rodless cavity enters other adaptive telescopic cylinders through the linkage oil way, and the oil liquid can generate a counter force to the telescopic rod when entering an oil through pipeline with a smaller size than the rodless cavity from the rodless cavity, so that the surface of the carbon fiber composite material of the contact part is subjected to a smaller pressure at the moment, thereby promoting more aluminum liquid of the part to flow to the periphery without extruding the aluminum liquid, starting the adaptive telescopic cylinder to extend out, setting the action speed of the adaptive telescopic cylinder to be slower and extending out to the thickness of the carbon fiber reinforced composite material to be processed, and in the slow pressurization process, because the adaptive telescopic cylinders uniformly distributed on the periphery are mutually communicated, therefore, the processing method combines the active pressurization of the balance rod and the passive deformation of the adaptive telescopic cylinder to form unique adaptive molding action, so that the aluminum liquid impregnation is uniform, the internal stress of the composite material can be eliminated, and the mechanical property of the carbon fiber reinforced composite material is further improved;
2) in the compression molding process, hydraulic cylinders with two movement speeds are adopted for action, a compression molding cylinder which runs at a high speed is adopted for in-place action when compression molding is started, and a balancing rod which can be finely controlled is driven for stretching and slow compression molding when compression molding action is required on the carbon fiber composite material, so that the compression molding process is suitable for the characteristics of the compression molding process of the composite material;
3) in the compression molding process, in order to ensure that the flatness of the finally molded composite material is ensured, after the balance rod stops acting, the valves between the adaptive telescopic cylinders are in a stop state, the adaptive telescopic cylinders are filled with liquid, and the levelness of a pressure head is adjusted to ensure the flatness of the carbon fiber reinforced composite material after compression molding;
4) in the compression molding process, the vacuum tube and the cold air tube are arranged in the lower mold at the same time, so that the mold can be vacuumized and cooled, and in the cooling process, the cold air tube is not communicated with the vacuum tube to ensure that no cold air is sucked in the vacuum tube in the cooling process, so that the working safety of parts such as a valve and a vacuum pump communicated with the vacuum tube is further ensured;
5) in the compression molding process, the heating resistance wires with the annular structures are arranged in the upper die and the lower die, so that the heating uniformity can be ensured compared with the existing heating resistance wires;
6) in the compression molding process, a special hydraulic circuit is arranged for adapting to the actions of the mold pressure cylinder, the balance rod and the adaptive telescopic cylinder, the hydraulic circuit is arranged in the sliding valve seat, and the structure of the hydraulic circuit is arranged far away from the heating resistance wire, so that the safety of hydraulic actions is further ensured, the action safety of each component of the hydraulic circuit is ensured, and the oil circuit structures for controlling the actions of the mold pressure cylinder, the balance rod and the adaptive telescopic cylinder are all integrated in the sliding valve seat, so that the hydraulic structure is simple and safe.
Drawings
FIG. 1 is a schematic structural view of a compression molding apparatus used in the compression molding process of the present invention;
FIG. 2 is an enlarged view of FIG. 1;
FIG. 3 is a view A-A of FIG. 1;
FIG. 4 is a schematic view of the shape of the heating resistance wire A in view B-B of FIG. 1;
FIG. 5 is a diagram of a hydraulic cylinder oil circuit;
FIG. 6 is a flow chart of a compression molding process of the present invention;
FIG. 7 is a schematic view of a half-closed mold structure;
FIG. 8 is a schematic view of the indenter contacting the blank;
fig. 9 is a schematic diagram of the position of the pressure head during cooling.
Description of the reference symbols
1. A base; 2. a guide bar; 3. a top frame; 4. a mould pressing cylinder; 5. an upper die; 6. a lower die; 7. a sliding valve seat; 8. a self-adaptive ram assembly; 9. a lower die cavity; 10. a carbon fiber reinforced composite material; 11. a vacuum tube; 12. a cold air pipe; 13. heating the resistance wire A; 14. a heating resistance wire B; 15. a heat insulation layer A; 16. a heat insulation layer B; 17. a pressure head; 18. a balancing pole; 19. a self-adaptive telescopic cylinder; 20. a hinged ball head A; 21. a hinged ball head B; 22. a carbon fiber cloth layer; 23. an aluminum powder layer; 24. a hydraulic pump; 25. an oil tank; 26. a two-position two-way solenoid valve; 19-1, a first adaptive telescopic cylinder; 19-2, a second self-adaptive telescopic oil cylinder; 19-3, a third self-adaptive telescopic oil cylinder; 19-4 and a fourth self-adaptive telescopic oil cylinder.
Detailed Description
The following describes a mode for carrying out the present invention with reference to the drawings.
As shown in fig. 1 to 5, a hot press molding apparatus used in a compression molding process of a carbon fiber reinforced composite material of the present invention includes: the device comprises a base 1, a guide rod 2, a top frame 3, a mould pressing cylinder 4, an upper mould 5 and a lower mould 6, wherein the guide rod 2 is fixedly connected between the base 1 and the top frame 2, the upper mould 5 is arranged on the guide rod 2 in a sliding manner, the mould pressing cylinder 4 is connected between the upper mould 5 and the top frame 3 and is used for driving the upper mould 5 to slide up and down along the guide rod 2, the lower mould 6 is fixedly arranged on the base 1, the middle part of the lower mould 6 is provided with a lower mould cavity 9, a carbon fiber reinforced composite material 10 is placed in the lower mould cavity 9 for mould pressing, the upper mould 5 comprises a sliding valve seat 7 and a self-adaptive pressure head assembly 8, the sliding valve seat 7 is arranged on the guide rod 2 in a penetrating manner, the self-adaptive pressure head assembly 8 comprises a balance rod 18, a self-adaptive telescopic cylinder 19 and a pressure head 17, the upper ends of the balance rod 18, the pressure head 17 is the rectangle structure, the balancing pole 18 is installed in the crossing point department of two axis lines of pressure head 17 of rectangle structure, self-adaptation hydro-cylinder 19 is preferred 4, be provided with two respectively on two axis lines, and two self-adaptation hydro-cylinders 19 on same axis line are the same from balancing pole 18, communicate each other through the pipeline between four self-adaptation hydro-cylinders 19, balancing pole 18 is also the telescoping cylinder structure, be used for driving pressure head 17 to carry out compression molding to carbon fiber reinforced composite 10, during compression molding, constitute dynamic balance hydro-cylinder group by four self-adaptation hydro-cylinders 19 of UNICOM and move, the surface of self-adaptation carbon fiber reinforced composite 10 makes pressure head 17 carry out the dynamic balance adjustment, thereby it is even to distribute the uneven aluminium liquid in the carbon fiber cloth layer during compression molding, further improve the flooding effect on carbon fiber cloth layer. Meanwhile, the dynamic balance cylinder group can absorb the stress in the carbon fiber cloth layer, the mechanical property of the carbon fiber reinforced composite material is further improved, and the die pressing and the dipping procedures are synchronously carried out. After the balance rod 18 completes the mould pressing process, the communicated oil circuit between the self-adaptive oil cylinders 19 is closed, and the self-adaptive oil cylinders 19 are filled with liquid through the hydraulic pump 24, so that the pressure head 17 is kept horizontal, and the flatness of the upper surface of the carbon fiber reinforced composite material is ensured. The processing mode combines the active pressurization of the balance rod and the passive deformation of the self-adaptive telescopic cylinder to form a unique self-adaptive molding action, so that the aluminum liquid is uniformly impregnated, the internal stress of the composite material can be eliminated, and the mechanical property of the carbon fiber reinforced composite material is further improved.
Preferably, the balance bar 18, the adaptive telescopic cylinder 19 and the pressure head 17 are respectively connected in a rotating way by using an articulated ball head A20 and an articulated ball head B21.
Preferably, in order to heat the carbon fiber composite material 10 in the lower mold, a heating resistance wire B14 is disposed in the lower mold 6, a heating resistance wire a13 is disposed in the ram 17, a heat insulation layer B16 is disposed at the lower end of the heating resistance wire B14 in the lower mold 6, and a heat insulation layer a15 is disposed on the back surface of the ram 17, as shown in fig. 4, the heating resistance wire a13 and the heating resistance wire B14 are both spiral structures, so that the temperature rise in the upper mold and the ram is uniform.
Preferably, in order to ensure a vacuum space when the carbon fiber composite material 10 is molded, a vacuum pipe 11 is arranged in the lower mold cavity 9, the vacuum pipe 11 is used for communicating with a vacuum pump, and in order to rapidly cool the carbon fiber composite material 10, a cold air pipe 12 is arranged in the lower mold cavity 9, and cold air is output from the cold air pipe 12.
Preferably, in order to protect the vacuum pump, the vacuum pipe 11 is located at the upper end of the lower mold cavity 9, and the cold air pipe 12 is located at the lower end of the vacuum pipe 11, so that the vacuum pump is started to suck vacuum after the pressure head 17 contacts the lower mold cavity 9, because the temperature in the lower mold cavity 9 is not raised to a high level yet, hot gas can be prevented from being sucked, the vacuum pump is protected, after the vacuum is sucked, the pressure head 17 continues to be pressed downwards, and at the moment, the pressure head 17 goes over the vacuum pipe 11, so that the vacuum pipe 11 is located outside the lower mold cavity 9, and the influence of the high-temperature gas is avoided; when the molded carbon fiber composite material 10 needs to be cooled, the pressure head 17 is lifted, so that the pressure head 17 is positioned between the vacuum tube 11 and the cold air tube 12, cold air is released, and rapid cooling is performed.
Preferably, in order to ensure that a sealed space can be formed in the lower die cavity 9, the periphery of the pressure head 17 is provided with a sealing plug structure, so that the pressure head 17 can ensure that the lower die cavity can also form a sealed space in the process of micro-rotation.
As shown in FIG. 5, the hydraulic oil circuit system in the sliding valve seat 7 is shown in the figure and comprises an oil tank 25, a hydraulic pump 24 and a two-position two-way electromagnetic valve 26, wherein the hydraulic pump 24 is respectively connected with the rod cavities of the balance rod 18 and the adaptive telescopic cylinder 19 through oil inlet pipelines, the hydraulic pump 24 is communicated with the balance rod 18 and the adaptive telescopic cylinder 19 through oil inlet pipelines, the two-position two-way electromagnetic valve 26 is arranged on each oil inlet pipeline, the number of the adaptive telescopic cylinders 19 is four, and the four adaptive telescopic cylinders are respectively a first adaptive telescopic cylinder 19-1, a second adaptive telescopic cylinder 19-2, a third adaptive telescopic cylinder 19-3 and a fourth adaptive telescopic cylinder 19-4, a part between the first adaptive telescopic cylinder 19-1 and the second adaptive telescopic cylinder 19-2, a part between the second adaptive telescopic cylinder 19-2 and the third adaptive telescopic cylinder 19-3, a part between the first adaptive telescopic cylinder 19-1, The third adaptive telescopic cylinder 19-3 and the fourth adaptive telescopic cylinder 19-4 are respectively communicated through a communication pipeline, two-position two-way electromagnetic valves 26 are respectively arranged on the communication pipelines, the oil inlet cavity of the balance rod 18 is also communicated with an oil tank 25 through an oil return pipeline, the oil return pipeline is provided with a two-position two-way electromagnetic valve 26, the rod cavities of the first adaptive telescopic cylinder 19-1, the second adaptive telescopic cylinder 19-2, the third adaptive telescopic cylinder 19-3 and the fourth adaptive telescopic cylinder 19-4 are communicated with the oil tank 25 through another oil return pipeline, and the other oil return pipeline bus is provided with a two-position two-way electromagnetic valve 26.
Preferably, in order to perform the resetting adjustment of the respective adaptive telescopic cylinders 19, a return spring is sleeved in the rod cavity.
Preferably, in order to detect the position of the ram 17, a level detector is installed at an upper portion of the ram 17.
As shown in fig. 6, the compression molding process of the carbon fiber reinforced composite material of the present invention includes the following steps:
firstly, placing a blank:
as shown in fig. 2, the blank is placed into a lower mold cavity of a lower mold of the hot press molding device according to the alternating sequence of the carbon fiber cloth layer, the aluminum powder layer and the carbon fiber cloth layer;
II, half-closing the mould:
the mold pressing cylinder 4 of the hot press molding device is driven to act, so that the pressure head 17 of the upper mold 5 quickly reaches the lower mold cavity 9 and contacts with the lower mold cavity 9, the lower mold cavity 9 forms a closed space due to the fact that the shape of the pressure head 17 is matched with the lower mold cavity 9, a half mold closing state is formed, the mold pressing cylinder 4 is stopped being driven at the moment, and for convenience, the illustration is shown in fig. 7;
thirdly, processing in a semi-molding environment:
starting a vacuum pump to suck vacuum in the space in the lower die cavity 9, starting a pressure head 17 and a heating resistance wire A and a heating resistance wire B in the lower die 6 to heat, and turning off the vacuum pump after the negative pressure in the lower die cavity 9 reaches a certain value, preferably, keeping the vacuum degree in the lower die cavity 9 below 1KPa, which is beneficial to the precipitation of air in the composite material fiber bundle, and simultaneously, continuing heating the heating resistance wire A and the heating resistance wire B until the melting temperature of the aluminum powder reaches 660 +/-3 ℃;
fourthly, continuously closing the mold:
starting the pressing cylinder 4 again to move so that the pressing head 17 continues to descend, at the moment, the carbon fiber cloth layers slightly deform due to different aluminum liquid impregnation degrees among the carbon fiber cloth layers, and closing the pressing cylinder 4 when the pressing head 17 contacts the highest deformation point H of the blank as shown in FIG. 8;
fifthly, self-adaptive molding action:
starting the extending action of the balance rod 18 to drive the pressure head 17 to continue to slowly descend, and the 4 adaptive telescopic cylinders uniformly arranged around the balance rod 18 are cut off from being connected with the hydraulic pump and are communicated with oil passages between rodless cavities between the adaptive telescopic cylinders, so that a dynamic balance oil cylinder group is formed, and the pressure head 17 freely rotating around the balance rod 18 is controlled by the dynamic balance oil cylinder group to act, specifically, as shown in fig. 8, when the pressure head 17 touches the highest point H of billet deformation, the balance rod 18 extends out, so that the pressure head continues to slowly descend, at the moment, the billet at the position H can generate a barrier force on the adaptive telescopic cylinder 19 at the position, so that hydraulic oil in the adaptive oil cylinder 19 is extruded into other 3 adaptive telescopic cylinders 19 through a communication pipeline, and as the oil has viscosity and enters a communication pipeline with a small cross section from a rod cavity with a large cross section, a certain resistance can be generated, therefore, when oil is pressed into other 3 self-adaptive telescopic cylinders, back pressing force can be generated on the blank at the position, so that redundant aluminum liquid can be extruded to other places. And because the four self-adaptive telescopic cylinders are communicated, when the balance rod 18 carries out slow die pressing, a balance oil cylinder group formed by the 4 communicated self-adaptive oil cylinders is always subjected to self-adaptive adjustment of the pressing head 17, the balance oil cylinder group can also absorb the stress in the blank through the structural design, and the balance rod 18 slowly compresses the balance oil cylinder group formed by combining the four communicated self-adaptive oil cylinders to jointly act on the pressing head 17 and further act on the blank to carry out self-adaptive die pressing on the blank.
Preferably, the speed of the balance bar 18 satisfies: the oil hydraulic pressure in the balancing rod 18 reaches 10MPa, and the whole adaptive molding action process lasts for more than 60 s;
sixthly, adjusting the levelness of the pressure head 17 of the upper die 5:
enabling the electromagnetic valves between the adaptive telescopic cylinders 19 to act, cutting off the communication between the adaptive telescopic cylinders 19, and then selectively filling liquid into the corresponding adaptive oil cylinders 19 according to the state of the pressure head 17 detected by the level gauge, so as to adjust the levelness of the pressure head 17, and continuously keeping 60 seconds until the levelness detected by the level gauge reaches the standard and stops acting;
seventhly, cooling:
after the time is reached, the mould pressing cylinder 4 is driven to contract, the driving pressure head 17 moves upwards, when the lower surface of the pressure head 17 is positioned between the cold air pipe 12 and the vacuum pipe 11, cold air output from the cooling pipe is rapidly cooled, and the cooling is stopped when the temperature reaches 60 ℃.
Eighthly, taking out the blank:
and taking out the carbon fiber reinforced composite material subjected to compression molding forming to obtain the processed carbon fiber composite material.
The carbon fiber reinforced composite material processed by the forming process is characterized in that the pressing head can perform corresponding actions in a self-adaptive mode while the carbon fiber reinforced composite material blank is subjected to die pressing due to the adoption of the self-adaptive die pressing action innovatively in the processing process, the pressing head can be dynamically adjusted in the whole die pressing process to adapt to the surface of the blank which is continuously changed, the stress in the carbon fiber cloth layer after the actions is absorbed, and the molten aluminum between layers is fully and uniformly impregnated, so that the mechanical property of the carbon fiber reinforced composite material after the model forming is remarkably improved.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims (4)

1. A compression molding process of a carbon fiber reinforced composite material is characterized in that: the method comprises the following steps:
firstly, placing a blank:
placing the blank into a lower die cavity of a lower die of a hot-pressing forming device according to the alternating sequence of the carbon fiber cloth layer, the aluminum powder layer and the carbon fiber cloth layer;
(II) half-closing the mould:
driving a mould pressing cylinder of the hot-press forming device to act, so that a pressure head of an upper mould quickly reaches a lower mould cavity and is in contact with the lower mould cavity to form a semi-closed mould state;
(III) semi-molding environment treatment:
starting a vacuum pump to suck vacuum in the space in the lower die cavity, starting a pressure head and a heating resistance wire A and a heating resistance wire B in the lower die to heat at the same time, turning off the vacuum pump after the negative pressure in the lower die cavity reaches a certain value, and simultaneously continuing heating the heating resistance wire A and the heating resistance wire B until the melting temperature of the aluminum powder reaches 660 +/-3 ℃;
(IV) continuously closing the mold:
starting the die pressing cylinder again to act, so that the pressing head continues to descend, and closing the die pressing cylinder when the pressing head contacts the highest point H of deformation of the blank;
(V) self-adaptive molding action:
starting a balancing rod to extend out to drive a pressure head to continuously and slowly descend, cutting off the connection with a hydraulic pump by 4 self-adaptive telescopic cylinders uniformly arranged on the periphery of the balancing rod, communicating oil passages between rodless cavities of the self-adaptive telescopic cylinders to form a dynamic balance oil cylinder group, enabling the pressure head freely rotating around the balancing rod to be controlled by the dynamic balance oil cylinder group to act, when the pressure head touches the highest point H of deformation of a blank, the blank at the position H can generate a barrier force on the self-adaptive telescopic cylinder at the position, so that hydraulic oil in the self-adaptive oil cylinder is extruded into other 3 self-adaptive telescopic cylinders through a communication pipeline, and when the oil is pressed into the other 3 self-adaptive telescopic cylinders, the oil can generate a back pressure force on the blank at the position, so that redundant aluminum liquid can be extruded to other places; the balancing rod slowly compresses tightly the action and combines the action of a balancing oil cylinder group formed by four communicated self-adaptive oil cylinders to jointly act on the pressure head, further act on the blank and perform self-adaptive molding action on the blank.
(VI) adjusting the levelness of the pressure head of the upper die:
after the self-adaptive molding action is finished, stopping the balance rod from continuously extending out, enabling the electromagnetic valves between the adaptive telescopic cylinders to act, cutting off the communication between the adaptive telescopic cylinders, and then selectively filling liquid into the corresponding self-adaptive oil cylinder according to the state of the pressure head detected by a level gauge arranged at the upper end of the pressure head, so as to adjust the levelness of the pressure head until the levelness detected by the level gauge reaches the standard stopping action, and continuously keeping for 60 seconds;
(VII) cooling:
and after the preset time is reached, the mould pressing cylinder is driven to shrink, the driving pressure head moves upwards, when the lower surface of the pressure head is positioned between the cold air pipe and the vacuum pipe, the cold air output from the cold air pipe is rapidly cooled, and the cooling is stopped when the temperature reaches 60 ℃.
(eighth), taking out the blank:
and taking out the carbon fiber reinforced composite material subjected to compression molding forming to obtain the processed carbon fiber composite material.
2. The compression molding process for a carbon fiber reinforced composite material as claimed in claim 1, wherein: and (3) in the step (III), the certain numerical value is that the vacuum degree in the lower die cavity is below 1 KPa.
3. The compression molding process for a carbon fiber reinforced composite material as claimed in claim 1, wherein: in the step (V), the balance rod is slowly molded, and meanwhile, a balance oil cylinder group formed by 4 communicated self-adaptive oil cylinders is used for self-adaptively adjusting the press head all the time, and the structural design of the balance oil cylinder group can also absorb the stress in the blank.
4. The compression molding process for a carbon fiber reinforced composite material as claimed in claim 1, wherein: in the step (V), when the balance rod is started to extend out and drives the pressure head to continue to descend slowly, the speed of the balance rod meets the following requirements: the oil hydraulic pressure in the balancing rod reaches 10MPa, and the whole adaptive molding action process lasts for more than 60 s.
CN201911015705.XA 2019-10-24 2019-10-24 Compression molding process of carbon fiber reinforced composite material Pending CN110920096A (en)

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