Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/28—Shaping operations therefor
  • B29C70/40—Shaping or impregnating by compression not applied
  • B29C70/42—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles
  • B29C70/46—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
  • B29C70/48—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs and impregnating the reinforcements in the closed mould, e.g. resin transfer moulding [RTM], e.g. by vacuum
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/0055—Moulds or cores; Details thereof or accessories therefor with incorporated overflow cavities
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/10—Moulds or cores; Details thereof or accessories therefor with incorporated venting means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/20—Opening, closing or clamping
  • B29C33/202—Clamping means operating on closed or nearly closed mould parts, the clamping means being independently movable of the opening or closing means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/28—Shaping operations therefor
  • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/28—Shaping operations therefor
  • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
  • B29C70/545—Perforating, cutting or machining during or after moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2101/00—Use of unspecified macromolecular compounds as moulding material
  • B29K2101/10—Thermosetting resins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2309/00—Use of inorganic materials not provided for in groups B29K2303/00 - B29K2307/00, as reinforcement
  • B29K2309/08—Glass

Definitions

• the invention relates to a device, as well as a method for manufacturing a molded part made of a composite material.
• composite material means a material comprising a resin (thermoplastic or thermosetting) and reinforcing fibers (for example glass fibers).
• the resin constitutes the matrix of the composite material.
• the matrix provides cohesion and orientation of the reinforcing fibers.
• the matrix allows the transmission of the mechanical stresses to which the molded part is subjected.
• the reinforcing fibers help to improve the strength and rigidity of the molded part.
• the composite molded parts are shaped for a variety of applications, such as the manufacture of crankcases, boat hulls, bicycle frames, body parts, tanks, various sanitary articles, or more generally all industrial parts with very different shapes and more or less complex.
• the RTM technique makes it possible to manufacture molded parts of small or large size. Injection molding is done with a rigid mold and counter mold. The reinforcing fibers are arranged in a cavity which is provided with the mold. The counter mold is fixed on the mold by a closing pressure obtained by means of a press or an autoclave. Then, the resin is injected by means of a low pressure pump (approximately 1 to 5 bar) through the reinforcing fibers until the cavity is completely filled. After curing the resin, the mold is opened and the part is demolded.
• a low pressure pump approximately 1 to 5 bar
• the moldings have forms of little or medium complexity
• the infusion technique for the manufacture of a composite material molding consists of vacuuming, in a mold covered with a superposition of fabrics and consumables which constitute a drapery and whose last thickness is a vacuum cover, fibers dry reinforcement, then to impregnate through the injection and migration of a resin in these reinforcing fibers due to the maintenance of the vacuum.
• the resin is then sucked by the vacuum created between the vacuum cover and the mold and thus penetrates the reinforcing fibers. Then, the vacuum is maintained during the polymerization of the resin, to ensure the pressurization of the reinforcing fibers. Vacuuming carried out before the injection of the resin makes it possible to compact the reinforcing fibers and to ensure that there is no air leakage.
• the draping generally consists of the following elements: tearing fabric and demolding fabric, diffusion grid, diffusion tube, draining fabric, vacuum cover and putty, in order to ensure optimal impregnation of the resin within the fibers of the fabric. reinforcement.
• the infusion is based in particular on the physical principle of the permeability of the reinforcing fibers
• the permeability of the reinforcing fibers consists of:
• the macroscopic permeability varies with the compression of the reinforcing fibers.
• the microscopic permeability depends on the tension of surface of the impregnating resin. The higher the surface tension, the more the impregnation of the fibers by capillarity is reduced.
• the viscosity of the impregnating resin is also an important parameter of the infusion: the lower the viscosity of the resin, the faster the infusion.
• the vacuum pressurizing reinforcing fibers may be disturbed by the resin which has been infused. It is essential that the reinforcing fibers remain under pressure until the end of the polymerization so as not to affect the mechanical properties and geometry of the molded part that is desired. However, the resin can obstruct the draw point of the vacuum;
• the face of the molded part which has been in contact with the draping does not have a smooth surface and free from defects, because the draping consists of flexible elements which do not make it possible to obtain a homogeneous surface.
• the infusion technique provides a molded part having a single smooth outer surface and free of surface defects.
• the present invention proposes to overcome the disadvantages inherent in the manufacture of a molded composite material from the known techniques that include the RTM and infusion and which were detailed above.
• the present invention firstly relates to a device for manufacturing a molded part made of composite material, designed to overcome non-reusable materials and more expensive, such as fabrics or consumables, during the manufacture of the molded part, as is the case for the infusion technique, and while ensuring the mechanical properties of the molded part as good as those obtained with the infusion technique.
• the device according to the invention is also designed to further have the advantage over the RTM technique of not requiring a means of closing the counter-mold on the mold of the press or autoclave type which are means which increase the cost of manufacturing a molded part made of composite material.
• the present invention also relates to a method of manufacturing a molded part made of composite material implementing said device.
• the device for manufacturing a molded part made of a composite material comprising a mixture of reinforcing fibers and a resin according to the invention comprises:
• a mold in which is formed a cavity configured for the arrangement of the reinforcing fibers
• a counter-mold which, intended to bear against the mold to close the cavity, is equi ped to the e ns a channel of introduction of the rés inedansla cav Institut, l ed it ca nal introducer being adapted to be connected to at least one source of resin supply;
• the mold and the against-mold comprise respective bearing areas surrounding the cavity, these bearing zones comprising two peripheral sealing seals offset from one another, from the inside to the outside, delimiting a closing chamber which is connected to a vacuum source, said vacuum source putting the closure chamber in depression to ensure the plating of the mold against the mold.
• the closure chamber is dimensioned according to the size of the molding, the pressure to be applied to the fibers and the injection pressure.
• the pressure on the reinforcing fibers disposed in the cavity may be of the order of 0.25 MPa before the injection of the resin: this corresponds to the accumulation of the the force provided by the closure chamber which can be approximately 0.15 MPa and that of the cavity. And once the resin is injected into the cavity, only the effort of the closure chamber remains.
• closure chamber makes it possible to dispense with a means for closing the mold against the mold of the press or autoclave type which are means which have the following drawbacks:
• the resin may be a thermosetting resin or a thermoplastic resin. Preferably, it is a thermosetting resin.
• depression of the cavity means adapted to introduce a residual vacuum of at least 200 mbar into the cavity of the mold, which corresponds to a vacuum of about 800 mbar.
• the residual void in the cavity is at least 50 mbar, corresponding to a depression of about 950 mbar.
• the resin from the supply source which may advantageously consist of a dosing pump system, is introduced into the cavity by the introduction channel.
• the resin then impregnates the reinforcing fibers that have been placed in the cavity and is sucked by the extraction channel because of the depression of the cavity.
• Resin is introduced into the cavity until an excess of resin exits through the extraction channel: at this stage, all the reinforcing fibers have been impregnated with the resin, because of the physical phenomena that are the macroscopic and microscopic permeability of these reinforcing fibers which have been detailed above for infusion.
• the depression means of the cavity comprises a vacuum pump, a channel formed in the counter-mold or in the mold for the depression of the cavity and the extraction of the excess resin. out of the cavity, and a vacuum circuit having the shape of a pipe which connects the vacuum pump to the channel.
• the tubing connecting the channel formed in the counter mold or in the mold to the vacuum pump is equipped with a buffer pot for collecting the resin extracted from the cavity.
• the buffer pot thus prevents resin from drowning the empty pump.
• the introduction channel and the extraction channel have a frustoconical shape. This provides the advantage of being able to easily remove from the mold by "demolding" the resin remained stored in these channels after the manufacture of the molded part and which will also polymerized. Thus, after the removal of this small amount of resin remaining in these channels in the counter-mold, the device is again ready for molding another piece of composite material.
• the closure chamber is connected to the vacuum source by means of a vacuum circuit in the form of a tubing and a channel formed in the counterpart. -mold or in the mold.
• the vacuum source is a vacuum pump.
• This vacuum also called “closing vacuum”
• the cavity vacuum circuit and the vacuum circuit of the closure chamber are arranged in parallel and converge upstream of the same vacuum pump.
• the cavity depression circuit and the vacuum circuit of the closure chamber can be equipped with measuring means and means for regulating the pressure and the flow rate.
• the closing gap is at least 300 mbar, which corresponds to a depression of about 700 mbar. Preferably, it is at least 200 mbar (corresponding to a depression of 800 mbar).
• the mold and the counter mold can be made of a composite material, metal or any other suitable material for the manufacture of a mold that is within the reach of the skilled person.
• the device further comprises at least one means for centering the mold against the mold.
• the cavity may comprise an area in which the resin is introduced through the introduction channel. During the manufacturing process of the molded composite material, the reinforcing fibers are not arranged in this area, this ensures a homogeneous impregnation of the resin within the reinforcing fibers.
• the present invention also relates to a method of manufacturing a molded part made of a composite material comprising a mixture of reinforcing fibers and a resin implementing a device as described above, which comprises:
• the reinforcing fibers are arranged in the cavity of the device
• a depression is instituted in the cavity with the depression means of the cavity and a closing vacuum is established in the closure chamber;
• thermosetting the resin
• step h) optionally, the molded part obtained in step h) is cut.
• the closing gap is selected such that the mold and counter-mold remain in contact during steps d) to f) of the manufacturing process.
• This setting of the closing gap will depend in particular on the nature of the joints of the device, the expansion of the reinforcing fibers, as well as the disengagement of the closure chamber. Of course, the parameterization of this closure vacuum is perfectly within the reach of the skilled person.
• a vacuum of at least 300 mbar, preferably at least 200 mbar, is introduced into the closure chamber.
• a depression in the cavity of at least 800 mbar, preferably at least 950 mbar, is instituted with the depression means of the cavity.
• step c) is carried out by introducing a depression in the cavity with the means of depression of the cavity of at least at least 800 mbar and a closing vacuum in the closing chamber of at least 300 mbar.
• the manufacturing method according to the invention does not require fabrics or consumables which are expensive materials and disposable.
• the cost of manufacturing molded parts with the process according to the invention is therefore reduced by the franking of these materials and the labor costs inherent in their careful handling.
• the manufacturing method according to the invention can be automated.
• the resin may be a thermosetting resin. It is advantageously chosen from the group consisting of:
• unsaturated polyester resins (optionally mixed with fillers such as calcium carbonate, so as to improve the appearance of the molded part and reduce its cost of manufacture);
• vinylester resins are used with fillers, catalysts and setting accelerators;
• epoxy resins Polymerized pieces obtained from epoxy resins have excellent fatigue resistance;
• the resin is a thermoplastic resin. It is advantageously chosen from the group consisting of polyether ether ketone, polyamides, polyetherimides, polyethylenes, polypropenes and polyphenylene sulfides.
• the resin used during the manufacturing process according to the invention is a thermosetting resin.
• the resin may further comprise fillers and / or pigments.
• fillers is understood to mean any inert, mineral or vegetable substance which, when added to the base resin, makes it possible to modify its mechanical, electrical or thermal properties, to improve the surface appearance, or even to reduce the cost of the molded part.
• the choice of load depends on the desired mechanical properties of the molded part. It can be organic fillers such as cellulosic fillers, wood flours, fruit and stone bark flours, vegetable fibers, starches, or mineral fibers. such as carbonates, silicas, talcs, clays and alumino-silicates, or oxides (oxides of zinc, magnesium, titanium and antimony, beryllium), alumina, ceramics, glass powders, hollow glass beads, glass microspheres or even carbon black.
• organic fillers such as cellulosic fillers, wood flours, fruit and stone bark flours, vegetable fibers, starches, or mineral fibers.
• the reinforcing fibers are advantageously chosen from glass fibers which are obtained from sand (silica) and additives (alumina, carbonate of lime, magnesia, boron oxide). It can also be carbon fibers or aramid.
• glass fibers are used as reinforcing fibers. They may be in the form of mats, preforms or possibly fabrics.
• the volume ratio of reinforcement can reach up to about 65%.
• the manufacturing process has the advantage of not implementing expensive mechanical means such as an autoclave or a press to maintain plated the counter-mold on the mold.
• the vacuum of the closing chamber and the depression of the cavity are carried out by means of the same vacuum pump, the cavity depression and setting circuits.
• vacuum chamber of the closure chamber being respectively equipped with measuring means (eg manometer) and pressure and flow control (eg valve).
• the molded parts according to the manufacturing method of the invention have the following advantageous characteristics which are very similar to those obtained with the infusion technique. They can be:
• the moldings obtained according to the manufacturing method of the present invention exhibit the advantage of having two smooth external faces and free of surface defects.
• the manufacturing method according to the invention is particularly suitable for the manufacture of crankcases, boat hulls, bicycle frames, bodywork elements, tanks, various sanitary articles, or more generally any industrial parts. with very different forms and more or less complex.
• FIG. 1 represents a schematic view of a device for manufacturing a molded part made of composite material according to the invention, in which the portion of the device representing the mold and the counter-mold is seen in section.
• Figure 2a is a view from above and in section of the mold according to a first embodiment of the invention.
• Figure 2b is a view from above and in section of the mold according to a second embodiment of the invention.
• thermosetting resin 3 which is a thermosetting resin is stored in a reserve pot 13.
• the thermosetting resin 3 is conveyed to the introduction channel 9 formed in the counter-mold 6 by a pipe 19.
• a cavity 5 has been formed in the mold 4.
• the reinforcing fibers 2 are arranged in the cavity 5.
• the mold 4 and the counter-mold 6 comprise respective bearing zones which surround the cavity 5. These bearing zones comprise two peripheral seals 1 1, 12 which delimit a closing chamber 22.
• the seal sealing 12 also has the function of preventing the thermosetting resin from spreading out of the cavity 5.
• the closing chamber 22 is connected to the vacuum pump 7 by means of the pipe 21 and the channel 8 formed in the counter mold 6.
• the tubing 21 is equipped with a manometer 16 measuring the closing vacuum and a valve 18 for regulating the pressure and the flow.
• the counter-mold 6 is equipped with a channel 1 0 for extracting the thermosetting resin 3.
• a tubing 20 connects the extraction channel 10 to a buffer pot 14 which makes it possible to avoid flooding the vacuum pump 7 with thermosetting resin 3, when the cavity 5 is depressurized and the thermosetting resin 3 is introduced into it.
• the tubing 20 is equipped with a manometer 15 measuring the depression within the cavity 5 and a valve 17 ensuring the regulation of pressure and flow.
• the tubing 20 connects the vacuum pump 7 to the channel 10.
• the vacuum can be established in a controlled manner in the cavity 5 and in the closure chamber 22.
• FIGS. 2a and 2b show two different embodiments of the zone 23 of which the cavity 5 is provided.
• the reinforcing fibers 2 are disposed in the cavity 5 with the exception of the zone 23.
• the thermosetting resin 3 is introduced into the zone 23 with the introduction channel 9. These two embodiments allow a homogeneous impregnation of all the reinforcing fibers 2 due to the control of the flow of the thermosetting resin 3 which migrates over the entire width of the cavity 5 (embodiment shown in Figure 2a) or all around the cavity 5 (embodiment shown in Figure 2b). There is no preferential path of the thermosetting resin 3.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Composite Materials (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Moulding By Coating Moulds (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=47754779

Family Applications (1)

Country Status (7)

Families Citing this family (4)

Family Cites Families (14)

• 2012
  • 2012-01-31 FR FR1250874A patent/FR2986179B1/fr active Active
• 2013
  • 2013-01-30 US US14/375,829 patent/US20150014898A1/en not_active Abandoned
  • 2013-01-30 EP EP13706588.4A patent/EP2809502A2/de not_active Withdrawn
  • 2013-01-30 CA CA2863155A patent/CA2863155A1/fr not_active Abandoned
  • 2013-01-30 RU RU2014131007A patent/RU2014131007A/ru not_active Application Discontinuation
  • 2013-01-30 CN CN201380007433.3A patent/CN104159725A/zh active Pending
  • 2013-01-30 WO PCT/FR2013/050183 patent/WO2013114037A2/fr not_active Ceased

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