GB2246536A - A model for use in moulding a mould - Google Patents

A model for use in moulding a mould Download PDF

Info

Publication number
GB2246536A
GB2246536A GB9113843A GB9113843A GB2246536A GB 2246536 A GB2246536 A GB 2246536A GB 9113843 A GB9113843 A GB 9113843A GB 9113843 A GB9113843 A GB 9113843A GB 2246536 A GB2246536 A GB 2246536A
Authority
GB
Grant status
Application
Patent type
Prior art keywords
model
resin
mould
surface
method
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9113843A
Other versions
GB9113843D0 (en )
Inventor
Keith Lightfoot
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Frank Smith And Son
Original Assignee
FRANK SMITH AND SON
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • 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
    • B29C33/00Moulds or cores; Details thereof or accessories therefor
    • B29C33/38Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
    • B29C33/40Plastics, e.g. foam or rubber
    • 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
    • B29C33/00Moulds or cores; Details thereof or accessories therefor
    • B29C33/38Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
    • B29C33/3842Manufacturing moulds, e.g. shaping the mould surface by machining
    • B29C33/3857Manufacturing moulds, e.g. shaping the mould surface by machining by making impressions of one or more parts of models, e.g. shaped articles and including possible subsequent assembly of the parts
    • B29C33/3892Preparation of the model, e.g. by assembling parts
    • 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS
    • B29K2071/00Use of polyethers, e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof as moulding material

Abstract

The model (1) e.g. of a counter, has a surface (2) e.g. produced by cutting, of a texture which is to be masked in a mould produced from the model, wherein the surface is provided with a smooth coating of a cured resin (3). The model may comprise an area (4) or (5) of a material e.g. a plastics laminate, with desired smooth or rough surface finish to be reproduced in the moulded article bonded to the base structure of the model. A mould may be produced by applying resin impregnated fibrous material onto the surfaces of the model to be reproduced, and curing the resin. The mould may then be used to produce a moulded article by applying resin impregnated fibrous material to the surfaces of the mould, and curing the resin. The texture to be masked is preferably provided in a model base of fiberboard e.g. medium density fiberboard, preferably masked by a furane resin coating. <IMAGE>

Description

IMPROVEMENTS RELATING TO MOULDING The present invention relates to moulding.

It is well known that a wide variety of articles may be produced from Glass Reinforced Plastics (GRP) by a moulding technique.

Particular examples of such articles are counters for shops or banks although many other examples could be quoted. The steps involved in the manufacture of the mould article include the production of a socalled primary model based on the original design drawing of the article. The primary model is, in effect, a 3-D version of the article as shown in the drawing. Well knows techniques are then used to prepare a mould from the primary model, which mould may then be used repeatedly for producing the final moulded articles.Clearly, any surface irregularities in the mould will result in corresponding irregularities in the finished article. SimIlarly surface irregularities in the primary model are translated into the mould produced therefrom and thus also appear in the finished article. Such surface irregularities in the model may be undesirable features (eg. surface imperfections in the primary model) or may be desirable features (eg.

a textured surface finish in the primary model).

So far as undesirable surface irregularities are concerned, these may occur in the production of primary models from fibreboard.

Fibreboard (eg. medium density fibreboard) is frequently used in the production of such primary models because it does not expand or contract and thus provides a stable model. There is however a problem with fibreboard in that if the article design calls for a decorative edge (eg. a facetted edge; it may be necessary to form the corresponding edge in the model by @@@@ing through the fibreboard.

In this case the comparatively rough texture of the inter or of the fibreboard produces undesirable surface irregularities in the finished article. The first aspect of the invention (described more fully below) aims to obviate or mitigate this disadvantage.

Additionally the surface fi@ish of the fibreb@ard ( r other material used for ccnstructlon of ti -' not surface finish required for the fi: - ae.; article. The sc-:ond spect of the invention (described more fully below) aims to obviate mitigate this disadvantage.

According to a first aspect of the present invention there is provided a model for use in the production of a mould, the model comprising a surface of a texture which is to be masked in a mould produced from the model, wherein said surface is provided with a smooth coating of a cured resin.

The mould may comprise fibreboard, particularly medium density fibreboard, and the surface whereof the texture is to be masked may be one which has been produced by cutting through the fibreboard which results in the internal texture being revealed. The surface may for example be one intended to form a decorative edge in the final moulded article.

The resin which is applied to the surface may be a liquid resin having a viscosity of 4-8 cp at 25C. Any suitable hardening agent may be included in the resin to effect curing thereof.

A preferred resin for use in producing a model in accordance with the first aspect of the invention is a furane resin based on a furfuryl alcohol polymer in methyl ethyl ketone. A suitable resin is available under the name Borden F/L-3 Furane resin. The preferred hardener is an aqueous solution of o-toluene sulphonic acid.

Whichever liquid resin is used, it is preferred to apply multiple coats of the resin to the surface of the model to cast. Most preferably each coat is allowed to cure fully and is rendered smooth before application of the next coat. Typically up to 15 coats of the resin will be applied with each coat being rubbed down between coats with 'wet and dry' paper (grades 400 to 1500). At least the final coat (and possibly also intermediate coats) are buffed and polished with cutting components to obtain a high gloss finish.

A second aspect of the invention relates to a model which has a desired surface finish which is to be reproduced in the final moulded article.

According to the second aspect of ttle present invention there is provided a model for use in the production of a mould the model comprising an area of a material with desired surface finish to be reproduced in the moulded article bonded to the base structure of the model.

As with the first aspect of the invention, the model may be constructed of fibreboard (eg. medium density fibreboard). Those areas of the model which in the final moulded article are to have a desired surface finish have bonded thereto a material which is of the same desired finish. This material may for example be a laminate material, particularly a Formica (Registered Trade Mark) or similar laminate material. Most preferably the laminate is a so-called post-formed laminate material. The laminate may for example be one having a very smooth surface finish or one having a textured finish.

The use of smooth laminates in accordance with the second aspect of the invention is particularly useful for producing comparatively large surface areas of the model with a smooth finish which is to be reproduced in the final moulded article. The use of such smooth laminates is generailv not suitable for providing a smooth finish at a narrow cut edge of a flbreboard model since the edge of the laminate will provide a surface irregularity between itself and the fibreboard. In such cases, it is much preferred to provide a smooth resin coating (as described above for the first aspect of the invention) to mask the edge, ie., by providin~ a smooth transition region between the faces of the laminate and fibreboard.

The models in accordance with the first and second aspect of the invention may be used for producing reinforced plastics moulds in which the final article may be produced.

Therefore, according to a third aspect of the present invention there is provided a method of Producing a mould from a model in accordance with the first or secant aspect of the invention, the method comprising applying resit; impregnated fibrous material onto the surfaces of the model to be reproduced, allowing the resin to cure, and removing the mould from the model.

Such moulds are produced by applying resin impregnated fibrous material (eg. glassfibre chopped strand mat (CSxI)) onto and around the surfaces of the model. The resin is cured (gerlel-aL in situ on the model) and the result is a -elnfor-ecl plastic mould all which can then be used for moulding of the final article. In order to facilitate release of the mould from the model, a release coat may be applied to the model before application.

According to a fourth aspect of the present invention there is provided a method of producing a moulded article comprising applying resin impregnated fibrous material to the surfaces of a mould in accordance with the third aspect of the invention, and curing the resin.

The invention will be further described by way of example only with reference to.the production of a GRP counter system, and to the accompanying drawings in which: Figure 1 is a schematic illustration of a length of medium density fibreboard (MDF) having facetted edges; and Figure 2 is a schematic illustration of the MDF of Figure 1 treated in accordance with the first and second aspects of the present invention.

1. PRIMARY MODEL Primary models were produced from drawings to high tolerance by skilled woodworkers. The models were made in semi-solid form in MDF, (medium density fibreboard). A synthetic 'formica' type laminate was applied by the 'post-forming' technique to the curved and flat surfaces which form approximately 90% of the visible area of the counter parts. Textured and gloss types of laminate were applied as required by the design. Models are basically solid MDF versions of the final GRP counter.

The model had various facetted edges formed by cutting through the fibreboard. These areas were too small (5mm) to cover with small pieces of laminate, and a way of covering the exposed cut edge of the post formed laminate was needed. This was achieved in accordance with the first aspect of the invention by the application of 'Furane resin which allows a high gloss surface to be built up by multiapplication and graded abrasion and polishing. In the tiny areas involved with the counter, very careful masking, rubbing-down and polishing were done to guarantee the quality of the finished product.

Quality finishing at this point reproduces through the following stages to the finished item. Finally, the models were fixed to a back plate of laminate faced chipboard, this would produce a flanged edge on the moulds.

The above described procedure is illustrated somewhat schematically in Figs. 1 and 2. Fig. 1 illustrates an MDF board l having facetted edges 2 formed by cutting into the board. These edges are of a comparatively rough texture (as defined by the interior structure of the MDF) which is to be masked in the finished moulded article. This masking is achieved by the layer 3 of furane resin applied as described above . Additionally, the area of the board 1 above the facetted edge is provided with a layer 4 of a laminate having a smooth surface first, and the area below the facetted edge is provided with. a layer 5 of laminate having textured surface finishes.

2. MOULD MAKING The completed model was prepared for mould making by the application of a special release agents and polishes, to allow the model to be withdrawn from the mould. A tooling gelcoat is then applied to the model and allowed to reach the 'Tacky' or 'Gelled' state.

(The gelcoat is a surface coating of polyester resin with accelerators and thickening additives). The desired number of layers of glassfibre CSM (chopped strand mat), core material and reinforcements, within a matrix of polyester resin, were hand applied in stages to avoid the excessive build-up of heat by 'Exotherm' (chemical reaction during curing3. The model and mould, once hardened or 'cured', were generally left in this state for several days to allow a full cure to build up. Then the model was parted from the mould and both inspected for damage. If the mould is satisfactory the Primary Sample is produced.

3. PRIMARY SAMPLE Primary sample means the first production item. The mould is prepared with a polish and release system which, not only protects and enhances the already high quality finish achieved from the model, but also ensures that mouldings can be easily withdrawn from the mould. This is followed by a similar gelcoat system to that described for mould making above, but here standard polyester gelcoats, in up to three separate colours, are applied by stages using a masking technique to give clean lines between colour breaks.

The specified laminate, typically 5-6mm, of (eg. polyester resin), glassfibre CSM (chopped-strand-mat), 'Corematt' core material and further glassfibre are applied by hand and compacted with rollers.

Finally, in the case of the Nosings and Rear Counters, pre-cut panels of 25mm thick chipboard, are clamped and weighted on the wet resin surface of the moulded components. Due to the tendency of even heavy material, such as 25mm chipboard, to deform by contraction when only one of it's surfaces is covered by a synthetic layer, such as resins, adhesives or even paints, the chipboard used has a 'balancing' layer of 'formica' type laminate already applied to the opposite surface to that presented to the GRP. This retains the desired flatness of the various counter sections, by counteracting this bending tendency. This is then left to cure until the following day when it is de-moulded, checked and excess material trimmed off. If all is satisfactory the mould is then prepared to make a master model.

4. MASTER MODELS Master Models are stable GRP versions of the Primary Models above. They are produced because the original models have limited dimensional stability, being made from organic material, which can expand, contract or deform unpredictably in variable atmospheric conditions. Also, where high volume production is expected and especially where textured finishes are used, it is imperative that a reliable, quick and accurate way of replacing damaged or worn-out production moulds is available. Gloss areas on moulds may be repaired, by refilling and polishing, but textured ares are generally unrepairable.

Master models are made out of the moulds using single coloured tooling gelcoat and structure similar to that for the moulds themselves described above. When complete and cured, these are demoulded and may be used to make further production moulds as required, or stored for future use. The final stage is Moulding Production.

5. MOULDING PRODUCTION Moulding production merely repeats section 3 above. However, as with all progressions from development to production, ways of accelerating and improving techniques are tried and tested to reduce work, time and materials. Templates are used to cut glassfibre mat and cores. Accurate measures of resin and catalyst are developed to give optimum working times. Polishing and masking techniques are refined to give the best finish and the cleanest colour lines, and so on. This soon leads to consistent and reliable volume production of high quality GRP mouldings.

Claims (29)

CLAIMS:
1. A model for use in the production of a mould, the model comprising a surface of a texture which is to be masked in a mould produced from the model, wherein said surface is provided with a smooth coating of a cured resin.
2. A model as claimed in claim 1, wherein the mould comprises fibreboard.
3. A model as claimed in claim 1 or claim 2, wherein the mould comprises medium density fibreboard.
4. A model as claimed in claim 2 or claim 3 wherein the surface of the texture to be masked has been produced by cutting through the fibreboard.
5. A model as claimed in any preceding claim, wherein the resin which is applied to the surface is a liquid resin having a viscosity of 4-8 cp at 250C.
6. A model as claimed in any preceding claim, wherein a hardening agent is included in the resin.
7. A model as claimed in any preceding claim, wherein the resin is a furane resin based on a furfuryl alcohol polymer in methyl ethyl ketone.
8. A model as claimed in claim 6, wherein the hardener is an aqueous solution of o-toluene sulphonic acid.
9. A model as claimed in any preceding claim, wherein the resin is applied to the surface of the model in multiple coats.
10. A model as claimed in claim 9, wherein each coat is allowed to cure fully and is rendered smooth before application of the next coat.
11. A model as claimed in claim 9 or claim 10 wherein up to 15 coats of the resin are applied.
12. A model as claimed in any one of claims 9-11, wherein each coat is rubbed down between coats with "wet and dry" paper of grades 4001500.
13. A model as claimed in any one of claims 9-12, wherein at least the final coat is buffed and polished with cutting componenets to obtain a high gloss finish.
14. A model for use in the production of a mould, the model comprising an area of a material with desired surface finish to be reproduced in the moulded article bonded to the base structure of the model.
15. A model as claimed in claim 14, wherein the model is constructed of fibreboard.
16. A model as claimed in claim 14 or claim 15, wherein the model is constructed of medium density fibreboard.
17. A model as claimed in any one of claims 14-16, wherein those areas of the model which in the final moulded article are to have a desired surface finish have bonded thereto a material which is of the same desired finish.
18. A model as claimed in claim 17, wherein the material is a laminate material.
19. A model as claimed in claim 17 or claim 18, wherein the material is a post-formed laminate.
20. A model as claimed in claim 18 or claim 19, wherein the laiminate has a very smooth surface finish.
211 A model as claimed in claim 18 or claim 19, wherein the laminate has a textured finish.
22. A method of producing a mould from a model in accordance with claim 1 or claim 14, the method comprising applying resin impregnated fibrous material onto the surfaces of the model to be reproduced, allowing the resin to cure, and removing the mould from the model.
23. A method as claimed in claim 22, wherein the mould is produced by applying resin impregnated fibrous material onto and around the surfaces of the model.
24. A method as claimed in claim 22 or claim 23 wherein the resin impregnated fibrous material is glass fibre chopped strand mat.
25. A method as claimed in any one of claims 22-24, wherein the resin is cured in situ on the model.
26. A method as claimed in any one of claims 22-25, wherein a release coat is applied to the model before application of the resin impregnated fibrous material.
27. A method of producing a moulded article comprising applying resin impregnated fibrous material to the surfaces of a mould produced according to the method of any one of claims 22-26, and curing the resin.
28. A moulded article produced by the method of claim 27 which is a counter.
29. A model substantially as hereinbefore described, with reference to the accompanying drawing.
GB9113843A 1990-06-27 1991-06-27 A model for use in moulding a mould Withdrawn GB2246536A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9014244A GB9014244D0 (en) 1990-06-27 1990-06-27 Improvements relating to moulding

Publications (2)

Publication Number Publication Date
GB9113843D0 true GB9113843D0 (en) 1991-08-14
GB2246536A true true GB2246536A (en) 1992-02-05

Family

ID=10678250

Family Applications (2)

Application Number Title Priority Date Filing Date
GB9014244A Pending GB9014244D0 (en) 1990-06-27 1990-06-27 Improvements relating to moulding
GB9113843A Withdrawn GB2246536A (en) 1990-06-27 1991-06-27 A model for use in moulding a mould

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB9014244A Pending GB9014244D0 (en) 1990-06-27 1990-06-27 Improvements relating to moulding

Country Status (1)

Country Link
GB (2) GB9014244D0 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000058066A1 (en) * 1999-03-31 2000-10-05 Gravutex Eschmann International Limited Rapid texture prototyping
US6558496B1 (en) 1997-11-28 2003-05-06 Eschmann-Stahl Gmbh & Co., Kg Rapid texture prototyping
US6565693B1 (en) 1997-11-28 2003-05-20 Eschmann-Stahl Gmbh & Co. Kg Rapid texture prototyping

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB176828A (en) * 1920-10-12 1922-03-13 John Stogdell Stokes Improvements in composite mats for making printing plates, sound records, and the like
GB523277A (en) * 1938-12-30 1940-07-10 Arthur Solomon Lewenstein Surfacing laminated sheets, plywood, wallboards, asbestos sheets and the like
GB956489A (en) * 1961-03-22 1964-04-29 Nl Siemens Mij N V A process and apparatus for manufacturing plastics articles
GB1190261A (en) * 1965-03-17 1970-04-29 C F Taylor Plastics Ltd Improvements in or relating to Laminated Plastics Constructions
GB1296428A (en) * 1969-10-09 1972-11-15
GB1502385A (en) * 1974-06-28 1978-03-01 Steenfabriek Windesheim Bv Process for producing bricks having a relief-structure as well as the thus obtained bricks

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB176828A (en) * 1920-10-12 1922-03-13 John Stogdell Stokes Improvements in composite mats for making printing plates, sound records, and the like
GB523277A (en) * 1938-12-30 1940-07-10 Arthur Solomon Lewenstein Surfacing laminated sheets, plywood, wallboards, asbestos sheets and the like
GB956489A (en) * 1961-03-22 1964-04-29 Nl Siemens Mij N V A process and apparatus for manufacturing plastics articles
GB1190261A (en) * 1965-03-17 1970-04-29 C F Taylor Plastics Ltd Improvements in or relating to Laminated Plastics Constructions
GB1296428A (en) * 1969-10-09 1972-11-15
GB1502385A (en) * 1974-06-28 1978-03-01 Steenfabriek Windesheim Bv Process for producing bricks having a relief-structure as well as the thus obtained bricks

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6558496B1 (en) 1997-11-28 2003-05-06 Eschmann-Stahl Gmbh & Co., Kg Rapid texture prototyping
US6565693B1 (en) 1997-11-28 2003-05-20 Eschmann-Stahl Gmbh & Co. Kg Rapid texture prototyping
WO2000058066A1 (en) * 1999-03-31 2000-10-05 Gravutex Eschmann International Limited Rapid texture prototyping

Also Published As

Publication number Publication date Type
GB9014244D0 (en) 1990-08-15 application
GB9113843D0 (en) 1991-08-14 application

Similar Documents

Publication Publication Date Title
Rudd et al. Liquid moulding technologies: Resin transfer moulding, structural reaction injection moulding and related processing techniques
US3907624A (en) Panel with decorative integral shaped edge and method of forming same
US6071619A (en) Method and spray mould assembly for manufacturing an elastomeric skin of at least two elastomeric materials and such elastomeric skin
US2613397A (en) Manufacture of molded articles
US5266257A (en) Method of making embossing rolls having indicia
US5177124A (en) Plastic molded pieces having the appearance of a solid metallic piece
US3903343A (en) Method for reducing sink marks in molded glass fiber reinforced unsaturated polyester compositions, and molded articles thereby produced
US4235948A (en) Simulated stone article and method for making same
US3929545A (en) Pressure laminating method
US3751319A (en) Method for making signs and other artistic works
US3427689A (en) Mold and method for the preparation thereof
US5413814A (en) Techniques for coating articles to have the appearance of wood, leather or other naturally occurring materials
US3957943A (en) Method for producing glass fiber reinforced plastic molded articles with decorative patterns and article produced thereby
US5338592A (en) Production method for composite molded article
US5863479A (en) Production method for a composite molded article
US6607683B1 (en) Methods and apparatus for producing manufactured articles having natural characteristics
US4158585A (en) Washbasin liner method and article
US3328500A (en) Method of making self-reinforced plastic articles
US6630093B1 (en) Method for making freeform-fabricated core composite articles
US3317640A (en) Method for making curved optical and reflective surfaces
US2319267A (en) Individual multilayer fibrous resinbearing article
US5264062A (en) Production method for composite molded article
US4863663A (en) Method of making a model, prototype part, and mold
US2724868A (en) Method of making tools and fixtures
US6517897B1 (en) Methods and materials for the manufacture of a solid surface article

Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)