US2118468A - Method of casting articles of intricate design and a product thereof - Google Patents

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y 1938. T. c5. JUNGERSEN 2,118,468

METHOD OF CASTING ARTICLES OF INTRICATE DESIGN AND A YRODUCT THERE'GF Filed Sept. 28, 1934 .Z'nVJenZon T/w er' ifun epsen.

PatentedMay 2 j 1 I I v UNITED- STATES PATENT" oFFlcE' METHOD or oss'rmo narrows or IN-I TRIGATE DESIGN AND. A monuor THEREOF Thoger G. Jungerscn, Mlmico, Ontario, Canada Application September 28, 1934, Serial No. 745,893

' 6 Claims. (01. 22-190) The principal object of this invention is to Thismould is then separated and the model is facilitate the casting of small metal articles, parremoved and the half sections of the mould are ticularly articles of intricate detail such as jewelbrought together again and placed in a suitable ry which frequently are designed with hollows, form of centrifugal casting machine 1.

undercut portions and perforations, so that they A suitable quantity of a very low temperature 5 will have a smooth clean surface faithful in defusing material which may be wax or a metallic tail to the original and free from imperfections alloy such as Woods' metal is poured into the or holes, and to enable such result being accomgate and the mould is rotated rapidly in the cenplished with the minimum of expense. trifugal casting machine. The wax or metal is i 10 A further object of the invention is to enable thus forced into the mould and by the centrifugal 10 the formation of intricate castings which will so action displaces the air within the mould, the

closely resemble the original and finished prodmolten material congealing first against the exuct that the slow and tedious work of patterning posed surfaces of the cavity formed in the I and detail cutting required in connection with mould and any air whlc may be trapped in a present casting methods is eliminated. recess of the mould will be crowded back into the The principal features of the invention are fluid body under the pressure applied thereto and hereinafter defined step by step in reference to the fluid material will advance into the recess as the accompanying drawing, in which Figure 1 is it crowds the air therefrom and will progressivea sectional view of a flexible mould which is built ly congeal against the wall of therecess until 20, in separable sections around a model of the the extreme limit is reached so that the finest of article to be reproduced. cavities will be completely filled.

Figure 2 is asectional view showing the fusible It s e t al at t e air e D d model of the article to be produced invested the mould progressively asthe molten material in the mould in which the article is to be cast. flows in so that all interstices whether undercut Figure 3 is a diagrammatic sectional elevationor o w are completely filled- 25 al view illustrating the manner of centrifugal When this step in the method has been comcasting of the fusible model and of the metal. pleted the mould is removed from the centrifugal In carrying this invention into effect the demachine and the flexible sections are separated. signer of a piece of jewelry or any small article The fl xib e rubber e l f om w c t to be cast produces amodel of the article in wood, mould is made permits the moulded wax to be 30 metal or other suitable material, and this may W t wn without u y t n e surfaces have undercut surfaces, hollows or perforations of 0 d l ate D I any desirable kind. This model is placed upon The pattern thus oduced s then v s d in a base and a. flexible mould-forming material a material which will form a suitable mould for 5 such as rubber, is built up around the model, the the metal which it is ultimately desired to form top surface being arranged to form a parting line to that shape. The Wax may e dipp d in a 5 along suitable lines of the model. lution of plaster of Paris or of silica, and it may 1 This bottom section i of the mould is formed then have an investment material such as plaster with a plurality of dowel or socket holes 2 arof Paris poured therearound, or it may be in- 40 ranged over the surface thereof closely around vested directly in a more or less fluid mass. 0 the model 3. When the lower mould section is This investing material may be dried out in completed the top section 4 is built thereover to any suitable manner, but is preferably dried in encircle the remaining portion of the model and a furnace, but in any event the mould created to form projecting teeth 5 to extend into the by the flowing material is subjected to suflicient guide holes in the lower section I. heat to melt the wax or other material of which 45' A suitable gate or pouring recess is formed in the temporary pattern is made and all traces of ,the meeting faces of the half sections of the this wax are completely removed from the mould. mould. The mould is then placed in the centrifugal The mould thus constructed is preferably made casting machine and the molten metal from .of rubber and when the rubber material comwhich the casting is to be made is poured into 50 pletely surrounds the model it is suitably vulthis mould and is projected under applied force canized and caused to flow intimately about the o the fine c sses Preferably y e 0611- detail structure of the model and thus assumes a trifugal action. Finally, the mould 'is separated permanent shape having a cavity the exact shape from the casting. 5 and detail of the model embedded therein. The flnal result is that an article is cast which is the exact replica of the original model. It

flexible mould is made any desirable number of the patterns of fusible material may be produced .to be invested in metal-receiving material to form moulds and any desirable number of metal casting moulds may thusbe produced from the same model. All will be equally accurate and as thev final mould is a complete investment of the wax or other fusible pattern, there will be a minimum of irregularities to be removed.

The ultimate result is that metal castings of rings, brooches and many pieces of jewelry which are frequently very fine and intricate may be produced at the very minimum of cost. For example, with known processes of casting rings, it may take an expert jewelry worker several hours to finish a ring to a certain standard after casting. while with the present process, only fifteen to thirty minutes may be required to finish a ring to the same standard. These figures are for ordinary rings, such as "Exhibit A on file herein. With finer work in platinum, from twelve to fifteen dollars worth of labor may be expended in making a ring by hand by known methods, while as little as ten minutes would cover the time of casting the same ring by the present process, and the time necessary for finishing it might cost as little as one dollar, or about one-twelfth of the cost of finishing the ring by known methods. The process of the present invention will produce rings on a quantity basis without the necessity of making dies,--a huge saving in itself, since a good set of dies costs from $100 to perhaps $1000. As compared with this excessive investment which the use of dies requires, the present process makes rings and other articles of jewelry at a total cost of from $2 to Thus a manufacturer employing this process may effect large savings in capital investment in dies and in precious metals (since a large number of rings etc., must be made at the same time from a die in order to justify the expense of a die,

while only a few rings need be made from a mould made in accordance with this invention to pay for the cost of the mould several times over). Hence it is clear that the process tion may efiect savings up to 90% in the cost of production, especially if the production is for orders of less than 1000.

It will be understoodthat this process is particularly applicable to the casting of precious metals, but it will also be understood that various other metals may be handled in the same way and particularly, base metals of tin and similar alloys.

What I claim as my invention is:-

1. A method of casting articles of jewelry of intricate design consisting in first producing a model of the article to be cast, then forming about said model a primary mould of a plastic material which will retaina lasting shape through subsequent treatment, then removing the model from the primary mould, then by centrifugal action forcing into the primary mould molten wax or other.material of a low fusing point that will not $3.50 for the first mould;

of the present invenauasee employing the patterns so made for the'manufacture of casting moulds.

2; A method of casting articles of jewelry of intricate design consisting in, first making a model of the article desired to be cast, then forming a primary mould in separable sections therearound of plastic material capable of assuming intimate contact with the intricate designs of the model and adapted to retain the assumed shape, then removing the model, then by centrifugal force projecting into the mould cavity and completely filling same a molten material of a low fusing point which will not injure the mould, then removing the fusible pattern so cast, then investing said pattern in a refractory material which will assume all the contours of its intricate design to form a secondary mould, then heat treating said investment removing the low fusing pattern therefrom, then by centrifugal force projecting molten metal into the heat treated mould, and finally removing said mould from the cast article.

3. A method of casting articles of jewelry as claimed in claim 1 in which the plastic material of which the primary mould is formed is treated to retain its assumed shape and after such treatment remains fiexible and is fiexed in the act of removing the model to withdraw the mould material from the intricacies of the model.

4. A method of casting articles of jewelry as claimed in claim 2 in which the pattern formed by projecting the pattern material into the primary mould under applied force and thereby provided with a surface free from imperfections is invested with refractory material, said refractory material being built up to a thickness sufiicient to withstand the stresses to be applied by forcing molten metal thereinto to form the article to be produced.

5. A method of casting an article of jewelry or a. part thereof of a design intricate to the extent of having one or more small projections or depressions, comprising first producing a model of the article to be cast, then forming about said model a primary mould, then removing the model from the primary mould, then introducing into the mould by force sufiicient to deposit the material into the depression or depressions of the primary mould molten wax or other material of low fusing point that will not injure the primary mould to form a pattern, and employing the patterns so niade for the manufacture of a casting mould. v

6. An article of jewelry or a part thereof of a design intricate to the extent of having one or more small projections or depressions made by a process comprising first producing a model of the article to be cast, then forming about said model a primary mould, then removing the model from the primary mould, then introducing into the mould by force sufflcient to deposit the material into the depression or depressions of the primary mould, molten'wax or other'material of low fusing point that will not injure the primary mould to form a pattern, and employing the pattern so made for the manufacture of a casting mould.

' THOGER G. JUNGERSEN.

a fluid coating of a finely ground I

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