Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
  • D21J7/00—Manufacture of hollow articles from fibre suspensions or papier-mâché by deposition of fibres in or on a wire-net mould
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B7/00—Moulds; Cores; Mandrels
  • B28B7/34—Moulds, cores, or mandrels of special material, e.g. destructible materials
  • B28B7/344—Moulds, cores, or mandrels of special material, e.g. destructible materials from absorbent or liquid- or gas-permeable materials, e.g. plaster moulds in general
• • 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
  • B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
  • B29C67/24—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00 characterised by the choice of material
  • B29C67/242—Moulding mineral aggregates bonded with resin, e.g. resin concrete
  • B29C67/243—Moulding mineral aggregates bonded with resin, e.g. resin concrete for making articles of definite length

Definitions

• the invention concerns.the manufacturing of moulded objects from a fluidized material.
• a fluidized material means a starting material, in wet form and of a fibrous nature, suitable for the pro ⁇ duction of the desired objects.
• a starting material in wet form may for instance be a fiber pulp material as used for instance for trays and cartons for packaging of fragile and sensitive objects such as fruit, flowers, eggs and objects of glass.
• the pulp material then usually consists of a suspended, fibrous cellulose.
• the starting material is by means of a depositing process placed against the outline-forming outside of a mould which is permeable to let a gaseous working medium affect the material through the material of the mould.
• bronze moulds are used with a coating of weaved nets made from stainless steel defining the outline-forming part.
• the bronze mould has through-going channels for ob ⁇ taining an even distribution of suction provoking vacuum all over the outline-forming outside of the mould.
• a deposit of fluidized material of the desired coating thickness is obtained on the outside of the mould, for instance by submerging the mould into a pulp material mass.
• the vacuum treatment may continue when the mould is then lifted out of the pulp mass so that the layer of material deposited on the mould is ex ⁇ posed to initial drying.
• the channels may then be used
• REPLACEMENTSHEET for the removal of the still moist moulded object from the mould by affecting the object by compressed air through the same channels.
• the object of the invention is to indicate a means by which it is possible, while maintaining an in itself adntageous depositing process, to obtain a reduction in the total manufacturing time calculated from the start of the manufacturing of the mould to the delivery of the produced object while simultaneously reducing the pro- duction cost of the moulds so that the production tech ⁇ nique dependent on a depositing process may be made more economical and thereby more attractive in the production of also small object series and/or specially moulded ob ⁇ jects.
• the invention concerns both a mould and a method for the manufacturing of moulded objects from fluidized material.
• the mould is characte ⁇ rized in that at least the outline-forming part of the mould is built up of a particulate stone-particle mate ⁇ rial whose stone particles provide a contour-stable outer outline, the said particles simultaneously together li ⁇ miting open passages extending through the material of the mould to the outside of the outline-forming part of the mould and being connected to a source for removal by suction of fluidizing liquid.
• Such a mould may be produced both from a cheap, in ⁇ organic raw material such as sand and by a production technique which is simple, of short duration and thus cheap compared with the time and cost consumed in the ma ⁇ nufacturing of the known deposit moulds described above.
• the stone material of the mould may consist of par ⁇ ticles of different particle size as the particle size is small in the outline-forming part of the casting mould and bigger in an underlying supporting layer for this part. In this way a good passage for air is achieved, a relatively smooth outside of the mould being simulta ⁇ neously at the disposal of the object to be produced, which will result in the object getting an even outer surf ce.
• the mould strength necessary for the carrying through of the production process may be obtained in a simple way by mixing the stone particles with suitable binding agents which may contain adhesion-improving a- gents and by hardening the mould produced from such a mixture by for instance heat treatment. Also wedging be ⁇ tween the stone particles may be used to give the mould strength.
• An appropriate structure of the mould is for the bottom of the mould to have a basic part in which the particles are linked together by a real fusion compound whereas the particles in the rest of the mould are linked together by a hardening conglutinating compound.
• Such a mould is characterized by good strength which will also enable it to resist considerable working pressure from for instance steam.
• the method according to the invention is, prior to the depositing of a layer of a fluidized material on the outline-forming outside of a mould which is permeable for a gaseous working medium, to manufacture a mould having the above-mentioned characteristics and at least the out ⁇ line-forming part of the mould being formed by a gravelly
• REPLACEMENTSHEET stone-particle material whose particles are bound to ⁇ gether for the formation of an open, stable structure with through-going passages for air to the outside of the mould and then to carry through the depositing on the mould thus formed.
• the total manufacturing process calculated from the beginning of the manufac ⁇ turing of the mould to the delivery of the produced ob ⁇ ject can be shortened considerably as it is no longer ne ⁇ cessary to produce an expensive metal mould. Owing to the achieved reduction in time as well as the use of cheap building material for the mould it becomes possible to use the above-mentioned depositing technique in an eco ⁇ nomically attractive way for the production of also small object series and/or for the production of specially moulded objects.
• the particles of the gravelly stone material are bound together prior to the start of the influence by the gas ⁇ eous working medium by the use of a binding agent having such surface tension that it will attempt to obtain its smallest surface size.
• the binding agent coalesces - for instance in connection with heating - a- round the particles of the mould building material thus avoiding clogging of the air passages between the par- tides as agglutination will only take place where the particles, are directly in contact with each other.
• a rounded shape of the particles of the building material may, according to the invention, be ap ⁇ limbate.
• the desired porosity of the mould may be checked and controlled by a suitable choice of the grain size of the particle material and the distribution of the grains in order to achieve both fa ⁇ vourable conditions for the agglutination connection be ⁇ tween the particles and a suitable dimensioning of the porosity in order to avoid an undesirable pressure drop over an unnecessary tight building material.
• the particles of the gravelly stone material may, prior to the start of the influence by the gaseous working medium, be bound to each other by using a binding agent which after the binding of the particles leaves a free surface which is smoothed.
• a satisfactory surface draft may be secured, also in cases where the outline-forming surface, owing to the above-mentioned surface-tension effect of the binding agent used for the agglutination of the partic ⁇ les, leads to a free surface which at first glance seems rough.
• the particles of the gravelly stone material may, prior to the influence by the gaseous working medium, be bound together by using a thermo-hardening binding agent.
• a thermo-hardening binding agent This involves the advantage of the hardened mould getting a good slip effect with regard to the mould against which the outline-forming surface of the mould has been mould ⁇ ed.
• the finished mould may thereby get such a degree of temperature stability that a high degree of freedom is achieved as regards cleaning of the mould by using heat.
• thermo-hardening bind ⁇ ing agent containing a liquable smoothing agent may be used.
• the mould may then for instance be exposed to treatment by wax, oil or a teflon product.
• the liquable smoothing agent can counteract an undesirable sediment or detention of fluidized material, for instance fibers, on the outside.
• a liquable smoothing agent will at the use of heat and suction be able to contribute to the cleaning of the porosities in the mould.
• the particles of the gravelly stone material may, prior to the start of the influence by the gaseous working medium, be bound " to ⁇ gether by the use of a binding agent which prior to the final binding of the particles shows adhesion-improving properties. This may result in easier shaping of the out ⁇ line-forming part of the mould.
• thermo-hardening binding agent is phenolic resin and the desired adhesion-improving pro- perties may for instance be obtained by also using si- lane.
• the above-mentioned process and mould may, as men ⁇ tioned, in practice be used for the production of objects from various starting materials, such as fibre-containing suspensions, everything in the presence of the ancillary materials which may be necessary to create connection in the layer of material obtained by suction onto the mould.
• the process may according to the invention be car- ried out by depositing fluidized material on the outline- forming part of the mould by means of a gaseous working medium in an actually known way by exposing at least this outline-forming part to a suction provoking vacuum as the mould can according to the invention be produced with the necessary strength.
• the transfer mould can be manufactured directly on the basis of an object produced on the cast- ing mould as on this object a first auxiliary mould (ne ⁇ gative) of for instance gypsum is produced corresponding to the side of the object pointing away from the casting mould and on this first auxiliary mould (negative) a se ⁇ cond auxiliary mould (positive) is produced for instance also from gypsum and the transfer mould (negative) is then formed directly on this second auxiliary mould.
• a first auxiliary mould (ne ⁇ gative) of for instance gypsum is produced corresponding to the side of the object pointing away from the casting mould and on this first auxiliary mould (negative) a se ⁇ cond auxiliary mould (positive) is produced for instance also from gypsum and the transfer mould (negative) is then formed directly on this second auxiliary mould.
• a suitable moisturizing of the stone-particle substance by adding liquid either in the form of water, a solvent or a bind- ing agent it will be possible in advance to give the stone-particle substance a consistency which ensures the necessary position or shape stability during the heat treatment.
• the moist stone-particle substance can the be dried to increase the stability of the substance before the hardening by heat is carried out.
• a stabilizing ef ⁇ fect may also be obtained by pre-heating the stone-par ⁇ ticle substance. The stabilization will then have been achieved when the stone-particle substance has been cool ⁇ ed. It is possible to reduce the hardening time by adding accelerators to the binding agent.
• a mould used in accordance with the invention can also be produced in such a way that it may, after use or in case of heavy wear, be regenerated as the particle- shaped building material of the mould may be recycled.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Ceramic Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Structural Engineering (AREA)
• Paper (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Mold Materials And Core Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8130068

Family Applications (1)

Country Status (10)

Cited By (7)

Families Citing this family (3)

Citations (1)

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• 1988
  • 1988-07-21 DK DK408888A patent/DK167254B1/da not_active IP Right Cessation
• 1989
  • 1989-07-19 PT PT9122389A patent/PT91223B/pt not_active IP Right Cessation
  • 1989-07-20 AU AU40332/89A patent/AU4033289A/en not_active Abandoned
  • 1989-07-20 CH CH110090A patent/CH679559A5/de not_active IP Right Cessation
  • 1989-07-20 BR BR898903603A patent/BR8903603A/pt not_active Application Discontinuation
  • 1989-07-20 WO PCT/DK1989/000180 patent/WO1990000944A1/en not_active Application Discontinuation
  • 1989-07-20 MX MX1687089A patent/MX171468B/es unknown
  • 1989-07-21 GR GR890100465A patent/GR1001014B/el unknown
  • 1989-07-21 CN CN 89106071 patent/CN1040409A/zh active Pending
  • 1989-07-21 ES ES8902585A patent/ES2016484A6/es not_active Expired - Lifetime

Patent Citations (1)

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