Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
  • B30B11/02—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space
  • B30B11/022—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space whereby the material is subjected to vibrations
• • 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
  • B29C43/56—Compression moulding under special conditions, e.g. 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
  • B29C2791/00—Shaping characteristics in general
  • B29C2791/004—Shaping under special conditions
  • B29C2791/008—Using vibrations during moulding

Definitions

• the present invention is concerned with moulding, and in particular a moulding technique which assists filling of a mould cavity with a mould material.
• a method of compression moulding which comprises:
• moulding apparatus comprising at least first and second moulding surfaces defining a moulding cavity, at least one surface being movable such that said surfaces are arrangeable at relatively distal and proximal positions with respect to each other;
• vibration of the moulding surface or surfaces substantially as hereinbefore described is advantageous for reducing the force required to close the cavity.
• the moulding cavity is defined by opposed first and second surfaces, and the surfaces may be respectively vibrated in opposed directions.
• the vibration is preferably such as to effect substantially complete filling of the cavity with the mould material.
• the vibration may involve transverse vibration of at least one moulding surface, so as to urge the thermosetting material to substantially fill the moulding cavity.
• the vibration may further comprise vibration of the opposed moulding surfaces between relatively proximal and distal arrangements, so as to assist compacting of the material between the surfaces.
• the transverse vibration of a moulding surface may involve transverse motion in more than one direction.
• the transverse vibration may involve substantially orthogonal vibratory motion of at least one surface.
• the material to be moulded comprises a thermosetting resin or plastics material.
• the resin or plastics material may be optionally mixed with fillers and fibre reinforcement.
• the thermosetting resin or plastics material may preferably be mixed with an initiator or catalyst for enhancing curing of the material.
• thermosetting material comprises a polyester resin mixed with slate dust and glass fibre reinforcement, together with a curing initiator.
• the material may further include additional ingredients such as crushed limestone and a lubricant such as stearate.
• the method may typically comprise a premixing stage, wherein the thermosetting resin or plastics material is admixed with the above preferred ingredients, prior to arrangement within the moulding cavity.
• the moulding process may be part of a substantially continuous compression moulding system, wherein a plurality of such processes are operated on a production line type method.
• moulding apparatus providing one or more cavities suitable for carrying out a process according to the present invention are arranged on a conveyor belt or the like, so that a plurality of moulding processes can be simultaneously operated.
• apparatus suitable for carrying out a moulding process substantially as hereinbefore described, which apparatus comprises:
• the apparatus comprises a plurality of moulding cavities, such that the apparatus is suitable to be employed in a substantially continuous compression moulding system as hereinbefore described.
• the moulding cavities are arranged on a conveyor belt or similar transfer surface as hereinbefore described.
• the vibrating means are advantageously capable of vibrating the moulding surface in a substantially controlled fashion as described above.
• the moulded article comprises a roofing tile.
• the thermosetting material comprises a slate filler
• the moulded article may preferably comprise a roofing tile having the appearance of natural slate, particularly when the moulding surface has a surface relief corresponding to that of natural slate.
• At least one moulding surface of the moulding apparatus hereinbefore described bears a complementary impression of natural slate.
• the present invention will now be further illustrated, by way of example only by reference to the accompanying drawing, which does not limit the scope of the invention in any way.
• the drawing is a schematic representation of apparatus according to the present invention suitable for use in compression moulding, and illustrates different stages during the moulding process.
• mould 1 comprising mould halves 2,3.
• the arrangement of mould 1 at progressive stages A,B,C of a compression moulding method is illustrated.
• a thermosetting material 4 is located in a mould cavity 5 between facing surfaces 2a, 3a of halves 2,3. Mould surfaces 2a, 3a are maintained at about 120°C, for effecting curing of material 4.
• Material 4 has been subjected to a pre-mixing stage, and weighed out as a batch of pre-determined weight prior to arrangement in cavity 5 as shown in stage A.
• stage A mould halves 2,3 are disposed in a distal arrangement for ease of insertion of material 4 into cavity 5.
• Surfaces 2a, 3a respectively comprise complementarily profiled raised and recessed formations.
• Side walls 3b are provided with a resilient surfacing 3c, such that on coupling of the mould surfaces damage to mould half 3 is reduced.
• mould half 2 is advanced towards mould half 3 so as to compress material 4 between surfaces 2a, 3a.
• the latter is vibrated in a substantially horizontal direction as shown by arrow D. This vibration urges filling of cavity 5 with material 4.
• Resilient surfacing 3c is also advantageous in absorbing the above described vibration of mould half 2.
• mould half 2 is also vibrated in a vertical direction as shown by arrow E, so as to aid compacting of material 4 between surfaces 2a, 3a.
• Mould 1 is clamped shut and surfaces 2a,3a heated until curing of thermosetting material 4 is complete and the moulded article is sufficiently rigid for removal from cavity 5.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Applications Claiming Priority (5)

Publications (1)

Family

ID=26301411

Family Applications (1)

Country Status (9)

Families Citing this family (6)

Family Cites Families (9)

• 1993
  • 1993-03-26 GB GB9306324A patent/GB2272856A/en not_active Withdrawn
  • 1993-08-09 WO PCT/GB1993/001684 patent/WO1994004335A1/en not_active Ceased
  • 1993-08-09 CA CA002142108A patent/CA2142108A1/en not_active Abandoned
  • 1993-08-09 SK SK169-95A patent/SK16995A3/sk unknown
  • 1993-08-09 JP JP6505991A patent/JPH07509672A/ja active Pending
  • 1993-08-09 AU AU47235/93A patent/AU4723593A/en not_active Abandoned
  • 1993-08-09 EP EP94908059A patent/EP0655967A1/en not_active Withdrawn
  • 1993-08-09 CZ CZ95336A patent/CZ33695A3/cs unknown
• 1995
  • 1995-02-10 RU RU95101847/25A patent/RU95101847A/ru unknown

Non-Patent Citations (1)

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