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
  • B29C70/30—Shaping 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
  • B29C70/34—Shaping 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
  • B29C70/345—Shaping 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 using matched moulds
• • 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
  • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
  • B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
  • B29C43/20—Making multilayered or multicoloured articles
  • B29C43/203—Making multilayered articles
• • 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
  • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
  • B29C43/32—Component parts, details or accessories; Auxiliary operations
  • B29C43/36—Moulds for making articles of definite length, i.e. discrete articles
• • 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
• • 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
  • B29C70/461—Rigid movable compressing mould parts acting independently from opening or closing action of the main mould
• • 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
  • B29C70/467—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 during mould closing
• • 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
  • B29C70/541—Positioning reinforcements in a mould, e.g. using clamping means for the reinforcement
• • 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
  • B29C70/543—Fixing the position or configuration of fibrous reinforcements before or during moulding
• • 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
  • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
  • B29C43/32—Component parts, details or accessories; Auxiliary operations
  • B29C43/36—Moulds for making articles of definite length, i.e. discrete articles
  • B29C2043/3602—Moulds for making articles of definite length, i.e. discrete articles with means for positioning, fastening or clamping the material to be formed or preforms inside the mould
• • 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
  • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
  • B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
  • B29C43/18—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2031/00—Other particular articles
  • B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
  • B29L2031/3055—Cars

Definitions

• SMC Sheet Molding Compound
• the SMC is in the form of a sheet of resin-impregnated fiber mat that is cut to desired dimensions before being deposited in an open mold.
• the closing of the mold causes the compression of the resin, its creep until filling of the mold cavity and finally its vulcanization under the effect of the temperature increase resulting from the compression (and possibly a heating of the mold ).
• Compression-molded SMC offers the possibility of local reinforcements by ribs or bumps, either by thickening the molded part in some places or by occasionally superimposing other pre-impregnated sheets having other proportions of fibers and of resin than the main SMC leaf.
• the methods of adding local reinforcements currently used involve either unimpregnated resin reinforcement sheets or impregnated sheets.
• the impregnation of the reinforcement is done by the resin of the main SMC sheet, also called base sheet.
• the reinforcement used is a non-impregnated resin sheet
• the amount of resin present on the SMC sheet to be reinforced is low (especially in the case of high-performance SMC loaded with 50% cut glass fibers)
• the total amount of resin is insufficient to properly impregnate the reinforcement and it may arise including moisture penetration problems in the finished parts.
• the mechanical properties of the assembly are not improved, or even they are degraded compared to the properties of SMC high performance alone.
• the mechanical properties of the assembly are then only slightly improved, except to provide oversized reinforcements so as to ensure that their extent is sufficient to continue to cover the area to be reinforced, even after a displacement of the reinforcement in the mold.
• the subject of the invention is a process for molding a part by compression of at least a first sheet containing plastics material, the compression causing the plastic material to flow in flow directions, in a mold in at least two parts closing one against the other, characterized in that the following steps are carried out:
• the reinforcing sheet is immobilized against a set of stops.
• the term "stop assembly” is understood to mean at least one stop.
• the set of stops may therefore consist of one or more stops.
• a set of abutments according to the invention can be obtained for example either by creating in the mold an extra thickness localized to the dimensions of the reinforcement, or by cutting in the first sheet, also designated base sheet, a cavity to the dimensions of the reinforcement for the integrate directly, before molding, to the molding structure. Thanks to the invention, the creep of resin resulting from the compression of the base sheet does not cause the displacement of the reinforcing sheet. By “does not cause displacement", it is meant that the reinforcing sheet does not move or moves very little in the mold during creep of the resin.
• the invention does not aim at a total immobilization of the reinforcing sheet but a holding position in the mold so that the area to be reinforced of the molded part is covered by the reinforcing sheet.
• the holding in position of the reinforcing sheet must above all be effective during the molding phase during which most of the creep of the plastic material occurs, that is to say at the beginning of the compression.
• the invention consists in providing means for maintaining the reinforcing sheet in position during the molding phase during which the plastic material, or resin, is distributed in the mold to fill it.
• the invention therefore makes it possible to use, as a reinforcing sheet, a sheet impregnated with plastic without encountering the problem of moving the reinforcing sheet during compression molding.
• the stop or stops of the set of abutments does not necessarily have a vocation to be durable. It suffices that the stop or stops of the set of stops fulfill their function of maintaining the reinforcing sheet during the massive creep phase of the resin. Beyond this phase, it is irrelevant that the stop or stops remain or disappear.
• the set of stops results from cutting the first sheet. This cutout shows the slice of the first cut sheet and this slice constitutes a set of stops to prevent the reinforcing sheet from moving during molding.
• the backing sheet is placed against the cut edge of the first sheet or base sheet.
• the resin that flows into the mold from the base sheet penetrates the reinforcing sheet in a plurality of opposite directions, so that the backing sheet experiences opposing transverse forces that reduce its tendency to move.
• the reinforcing sheet is blocked transversely by the cut edge of the base sheet.
• the base sheet loses its stiffness and its slices from the cut form less rigid barriers. But at this later stage of molding, the resin has almost completely filled the mold and the risk of movement of the backing sheet has disappeared.
• the set of stops is formed by at least one transverse wall of the mold. This wall may be permanent or temporary.
• a fixed transverse wall may result from the realization in the mold of a recessed housing for receiving the reinforcing sheet before closing the mold.
• a transverse wall may also result from the presence of a rib in the mold, against which the reinforcing sheet is placed to wedge it transversely.
• the molded part has a shape that reflects the presence of this transverse wall.
• this form is not a problem.
• the piece may comprise a boss that corresponds to the hollow recess made in the mold.
• the transverse wall is designed to be temporary.
• the mold may comprise a movable part which can take a retaining position in which the transverse wall is formed and makes it possible to retain the reinforcing sheet and a molding position in which the transverse wall disappears.
• the moving part is positioned in the molding position when the creep of the plastic material in the mold has reached a stage where the risk of driving the reinforcement sheet is considered to have been eliminated.
• a first example of a moving part is a core whose section is that of a recessed housing in which it is desired to deposit the reinforcing sheet.
• the core When the core is recessed, the hollow recess is formed, while when the core is flush with the surface of the surrounding wall of the mold, the housing disappears.
• the core is set back while the mold is still open.
• the reinforcement sheet is then deposited in the recessed housing.
• the base sheet intended to constitute the remainder of the part is then placed on top of the reinforcing sheet, then the mold is closed (the positions can be reversed if the housing is above and not below the sheet of based).
• the core just before the end of the molding, the core is moved to flush in the mold to remove any relief on the part due to the presence of the reinforcing sheet.
• a second example of a moving part is a retractable rib.
• the rib When the mold is open, the rib is out and the reinforcing sheet may be arranged against the rib, acting as a transverse wall which retains the reinforcing sheet during creep of the resin.
• the mold is closed until the resin has almost completely filled the mold.
• the rib is then retracted and the closure of the mold is completed.
• the reinforcing sheet no longer moves because the movements of material due to creep are very small and the removal of the rib avoids leaving traces on the part obtained.
• the first plastic material consists of SMC TD (30% FV + UP) or SMC HP (50% FV + VE).
• the reinforcement sheet is made of continuous fiberglass reinforcements, impregnated or non-impregnated.
• the invention also relates to a part obtained by the implementation of the method described above, as well as to a motor vehicle part, characterized by the presence, in at least one location of the part, of a thickening of a plastic material reinforced with reinforcing fibers and whose fiber content or the orientation of the fibers differs from the fiber content or the orientation of the fibers of the material of which the piece is made to said location.
• FIG. 1 represents rolls of impregnated fiber mat sheets used in an embodiment of FIG. the invention
• FIG. 2 is a sectional view of an open mold in which the pre-cut sheets have been deposited for molding purposes;
• - Figure 3a is a sectional view of an open mold and empty in the matrix of which was dug a set of stops, here in the form of a cavity
• - Figure 3b is a sectional view of an open mold and empty in the punch of which was dug a set of stops, here in the form of a cavity;
• FIG. 3c is a sectional view of an open mold and empty in the punch of which was dug a set of stops, here in the form of protruding ribs;
• - Figure 4a is a set of sectional views illustrating the closure of the mold (empty) in case of movable stops;
• FIG. 4b is a set of sectional views illustrating the closure of the mold (empty) in case of movable stops.
• FIG. 1 shows two rolls 1 and 2 of resin-impregnated fiber mat sheets (uncooked SMC), the use of which is common in the manufacture of parts made of compression-molded reinforced material.
• the roll 1 represents a roll of a first sheet containing plastic, the main material of which will be made the piece to be molded.
• the cutting of the mat of the roll 1 will give the (or) main sheet (s) 3.
• the roll 2 represents a roll of a second sheet containing the reinforced plastic fiberglass material, said reinforcement.
• the cutting of the mat of the roll 2 will give the reinforcing sheet 4 which will be used to strengthen punctually the piece formed by the main sheet 3.
• a first embodiment is that the set of stops is obtained by cutting the or (they are here three) base sheets 3.
• the cutout thus shows the slices of the sheets of base 3 which will form the set of abutments 5-1.
• the reinforcing sheet 4 precut according to the shape given to the set of abutments 5-1, is then placed in the recess formed by the set of abutments 5-1.
• the reinforcing sheet 4 is immobilized against the slices of the base sheets 3 during the start of the molding, ie while the movements of the material due to creep are the most important.
• the resin indeed flows into the mold 6 from the base sheets 3 and penetrates the reinforcing sheet 4 in several opposite directions, so that the reinforcing sheet 4 undergoes antagonistic transverse forces which reduce its tendency to move.
• the reinforcing sheet 4 is blocked transversely by the cut edge of the base sheets 3.
• the set of abutments 5-1 will finish, at a later stage of the molding, by softening and the cut slices by forming less rigid barriers, it will not be a disadvantage because, at this stage of the molding, the resin will have almost completely filled the mold 6 and the risk of displacement of the reinforcing sheet 4 will be zero.
• other embodiments have been designed to remedy this eventuality.
• FIG. 3a shows an embodiment in which the set of stops 5-2 is cut in the die 7a of the mold 7. This is a case where the set of stops 5-2 is permanent.
• the molding results in a thickening localized to the reinforced zone of the molded part.
• the reinforcing sheet 4 is placed in the recess formed by the set of abutments 5-2 in the die 7a of the mold 7 (under the base sheet (s) 3) and will thus be prevented from flow during molding.
• FIG. 3b shows an embodiment in which the set of stops 5-3 is cut into the punch 8b of the mold 8. This is a case where the set of stops 5-3 is permanent and it will result from this molding an extra thickness localized to the reinforced zone of the molded part.
• the reinforcing sheet 4 is placed in the recess formed by the set of stops 5-3 in the die 8b of the mold 8 (over the base sheet (s) 3) and will thus be prevented. to flow during the molding process.
• FIG. 3c shows an embodiment in which the set of abutments 5-4 is formed of a set of ribs 10 projecting from the punch 9b of the mold 9.
• the set of abutments 5-4 is permanent and it will result from this molding localized hollows on the edges of the reinforced zone of the molded part.
• the reinforcing sheet 4 is placed in the area delimited by the set of ribs 10 projecting from the punch 9b, forming the set of stops 5-4 of the mold 9 (under the sheet (s) base 3) and will thus be prevented from flowing during molding.
• FIG. 4a A first variant of this embodiment is illustrated in FIG. 4a.
• the punch 11b of the mold 11 has a movable portion.
• a first example of a moving part is a core 12 whose section is that of a recessed housing in which it is desired to deposit the reinforcing sheet 4.
• the core 12 When the core is in removal, the hollow recess is formed and provides the set of stops 5-5, while when the core is flush with the surface of the surrounding wall of the mold, the housing disappears, causing the disappearance of the set of stops 5- 5.
• the core 12 is set back while the mold 11 is still open. The reinforcing sheet 4 is then deposited in the recessed housing.
• the base sheet (s) 3 (s) intended to form the remainder of the piece are then placed on top of the reinforcing sheet 4, then the mold 11 is closed. Before the die 11a is completely lowered, the movable portion 12 is raised, resulting in the disappearance of the set of stops 5-5 which held the reinforcing sheet 4 in place. However, as for the first embodiment, at this stage of the molding, the resin will already have almost completely filled the mold 11 and the risk of displacement of the reinforcing sheet 4 will have disappeared.
• FIG. 4b A second variant of this embodiment is illustrated in FIG. 4b.
• the punch 13b of the mold 13 comprises a movable part.
• the moving part is a set of retractable ribs 14 which form, when the mold is open, the set of stops 5-6.
• the reinforcing sheet 4 may be disposed against said ribs, and the set of ribs 14 then acts as a transverse wall which retains the reinforcing sheet 4 during creep of the resin.
• the mold 13 is closed until the resin has almost completely filled.
• the set of ribs 14 is then retracted, making the set of abutments 5-6 disappear and the closure of the mold 13 is completed.
• the reinforcing sheet 4 no longer moves because the movements of material due to creep are very small and the removal of the rib assembly 14 avoids leaving traces on the piece obtained.
• the invention thus provides an advantageous and economical solution to the production of locally reinforced parts, without the disadvantage of using oversized reinforcements.

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

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• 2013
  • 2013-12-31 FR FR1363747A patent/FR3015923B1/fr not_active Expired - Fee Related
• 2014
  • 2014-12-23 WO PCT/FR2014/053524 patent/WO2015101741A1/fr active Application Filing
  • 2014-12-23 EP EP14833520.1A patent/EP3089863A1/de not_active Withdrawn

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