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Publication numberUS2629907 A
Publication typeGrant
Publication date3 Mar 1953
Filing date19 Apr 1949
Priority date19 Apr 1949
Publication numberUS 2629907 A, US 2629907A, US-A-2629907, US2629907 A, US2629907A
InventorsRichard H Hugger
Original AssigneeUs Rubber Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of making molds
US 2629907 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

March 3, 1953 R. H. HUGGER 2,629,907

METHOD OF MAKING MOLDS Filed April 19, 1949 mwza #5744 mm .A TTOFNEY Patented Mar. 3, 1953 METHOD- OF MAKING. MOLDS Richard H. Hugger, Ridgewood, N. J assignor to United States. Rubber Company, New York, N. Y., a, corporation? of New Jersey Application April19, 1949, S'erialN0..88;364:

11 Claims.

This invention, relates to the manufacture Qf: molds wherein a metal negative of a mold model is prepared by spraying metal upon the mold model which may be of any suitable material such as rubber, metal, plaster, wood, etc. After building up the metal negative to a suitable thickness and strength, either by continuedspraying of the same metal or of a, diiierent metal or by electro-deposition or in any other suitable man-. ner, the sprayed metal negative is separated from the mold model.

In attempting to. makev molds by the process just described, a number of serious difficulties arise and as a. consequence no entirely satis-. factory method of making sprayed metal molds hasbeen known to theart. The principal diificulty is that of separating the sprayed metal negative from the model; usually the sprayed metal adheres so tightly to the model that separation is very difficult or often impossible. Another diincultyarises from the fact that at the start of spraying the metal does not adhere to the surface ofthe model because of the force.

of the blast and the lack of adhesion to the surface; expressed otherwise, the deposit. efficiency at. the start. of the spraying is objectionably low. Asa result, a great deal of metal is wasted and. an excessive amount of time is consumed.

Because of the foregoing phenomena, it is almost impossible by prior methods to successfully make a sprayed metal negativeon a smooth or highly finished metal model unless resort ishad to complicated and expensive procedures such as use of an intermediate metal covering on the mold model or of a metal mold model which is heated to an elevated temperature. at least until the model has been entirely covered with sprayed metal.

In the-case of rubber mold models, it has been impossible to obtain satisfactory results because the metal spray blows oil so that it is difficult to start the building-up of the sprayed metal layer and because the metal burns and-penetrates the rubber surface with the result that even though separation be effected in spite of great difficulty, the impression surface of the sprayed metal is rough so that it is not satisfactory as a molding surface.

I have made the surprising and remarkable discovery that the foregoing" difficulties in making sprayed, metal negatives of mold models can be completely; overcome in a simple and economical' manner and without any disadvantages by coating the surface of the mold model evenlywith nylon (which is a synthetic linearcondensation 2 polyamide) before beginning the metal spraying. The n onv coa n exh isf he s rp s ng result that the metaLsprayadheres at once and evenly over the area encountered by the metal spray. There isv no tendency for the metal spray to blow off or bounce off. It is well known in prior prac-a ties that hen... a par cleo molten metalv s a surface it splashes; However, when. it strikes a nylon sur a iit. do s. n t plash. o t i tained uniformly at the, instant of contact. As a result, there is no period of lessened deposit efficiency at the start of spraying; thusgreater production is adepo ible.

Furthermore, the; case of rubber mold. models made of ordinary soft vulcanized rubber and coated with nylon, there, is. no burning or the. rubber, so that the. sprayed metalsurfaee ob-.-. tained on separation is smooth and unbroken, and free from; rubber particles, and the rubber mold model is uninjured and can be used again, and again. This is. in marked contrast to the results obtained when, the nylon coating of my inventionis omitted; inisuch case itis so difiicult.

to get. the metal spray to take that the surface of. the rubber; is actually burned. and; decomposed.

before adhesion. begin Also the. use of nylon makes possible easy separation of. the spraYQd metalfrom the mold: model. Thus nylonv exhibits the surprising ad,- antae s ofcausin much bet er a he io o molten metal spray and at the, same time-per-- mitting subsequent; clean, separation,

In addition totheforegoing advantages bro ght about by the use. of anylon coating on, themoldmodel in accordance with my; inyention, 1, 3 .13? other advantages are obtained, The coating; of nylon may be made verythin, and in this way details of'the mold modelare accurately preserved and reproduced in. the sprayed metal negative surface. It would be difiicult to accurately state the exact. thickness 01" the nylon coating applied, for itmay varywithin. very wide limits. Usuallythe coating has a thicknesssuch asis-v obtainedby applying one coating of a: 11% t0,.:20 solution of nylon in a suitable. organic solvent; andevapcrating the solvent.

A nylon coating provides the necessary high film strength and thermal stability: to withstand the impingement of the molten metal, from the metal spray. gun. Nylons. are readily available which exhibit the desired high, soften ng point required to. withstandv the. molten metal spray. I prefer to. employ those nylon polymers which have softening temperatures of. 300 R. or higher in order that. the coating" obtained shall; not-be 3 melted and deformed to an objectionable extent upon the impingement of the molten metal particles.

As a result of the foregoing advantages, a nylon coating gives very remarkable results as a parting agent in the manufacture of sprayed metal molds.

In making sprayed metal molds in accordance with my invention, inexpensive mold models are almost invariably used and in fact are required for commercial production. Such models may be made of plaster, rubber, wood or metal, including metals of low melting point such as lead and low melting point alloys. The mold models used may be rough or may have any surface configuration whatsoever. For example, the method of my invention enables the most minute patterns or structures in the surface of the model to be accurately reproduced, even though the model be made of rubber or a low melting point metal. The invention is equally applicable to highly finished, i. e., smooth, mold models.

In practicing the present invention, I apply a uniform nylon coating over the entire surface of the mold model in any suitable way. I may apply the nylon in any manner which gives an unbroken film of nylon over the face of the mold model. I find it most convenient to apply the nylon in the form of a solution in any suitable organic solvent which can be volatilized by drying at room temperature or at an elevated temperature. The solids content of the solution used may vary as desired according to the mode of application and the thickness of the coating desired. The solution may be applied to the mold model in any suitable manner, as by dipping, brushing or spraying. For brushing, the nylon content of the solution may typically range from 5-15% by weight. For spraying application, a somewhat lower nylon content, say 1-4% by weight is generally desirable.

Any solvent for nylon may be used in making up the solution. I often use an alcohol-soluble nylon polymer and use a solvent comprising a lower aliphatic saturated monohydric alcohol to dissolve it. Very often I use a mixture of solvents.

A single coatin with the nylon solution is sufficient. However, if desired a plurality of coatings may be applied with drying after each application. The thickness of the nylon coating applied should be suflicient to give good parting of .the sprayed metal mold, but not so great as to obliterate the surface detail of the mold model. The coating should be applied in such manner that the surface of the nylon coating accurately conforms to the surface of the mold model.

After application of the nylon solution, it is dried. As soon as the coating is dry, spraying with the molten metal spray can be begun. After a sprayed metal layer of the desired depth has been built up, with Or without further deposition of metal upon the spray deposit in any suitable manner, for example by continued spraying with the same or a different metal or by electro-deposition, the sprayed metal layer is separated from the mold model by simple mechanical separation.

The manner of spraying the molten metal to build up the sprayed metal layer need not be set forth in detail because it is the well-known and conventional method of spraying molten metal. In the case of porous mold models, especially those made of plaster, separation of the metal negative from the model can be facilitated by application of a solvent to the interface through the porous mold model. Any inert solvent for the nylon may be used for this purpose, the lower aliphatic saturated monohydric alcohols, for example isopropyl alcohol, being usually employed.

The accompanying drawing is a vertical sectional view f a mold model upon which a sprayed metal negative has been deposited in accordance with my invention. The mold model is designated by reference numeral I. To model I there is applied a coating 2 of nylon in the manner described above, the thickness of this coating 2 being greatly exaggerated. Thereafter molten metal is sprayed onto the surface of the coated mold model until a layer 3 has been built up. If desired, the application of the sprayed metal layer 3 may be followed by electro-deposition of more metal in order to make a mold of still greater thickness. Alternatively, there may be superimposed upon layer 3 a sprayed metal layer of another metal. For example, it is often highly desirable t have an initial layer of zinc backed by a sprayed layer of aluminum for strength.

The following formulations are typical of those which may be used to form the nylon coating of my invention.

Example 1 Parts by weight Nylon powder (softening point at least 300 F.) Isopropyl alcohol 176 Denatured ethyl alcohol 44 Furfuryl alcohol 10 Water 5 Example 2 Parts by weight Nylon powder (as in Example 1) 2 Isopropyl alcohol 98 Furfural The foregoing ingredients are mixed in the same manner as in Example 1. The resulting formulation is especially suitable for application by spraying.

Example 3 Parts by weight Nylon powder (as before) 5 Isopropyl alcohol 76 Water 19 These ingredients are mixed as before and give a brushing solution which evaporates somewhat more rapidly than the formulation given in Example 1.

From the foregoing description it will be seen that the present invention provides a very successful solution of the problem of making sprayed metal models. The process of my invention is particularly advantageous because of the ease and rapidity of parting of the sprayed metal mold from the mold model and the uniform and unbroken surface of the sprayed metal mold obtained. The process is simple and economical and is such that the operator can consistently obtain excellent molds without special training. Many other advantages of my invention will be obvious to those skilled in the art.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. A method of making a sprayed metal mold which comprises coating a mold model with a thin. continuous, uniform, smooth coating of a synthetic linear condensation polyamide, spraying molten metal upon the polyamide-coated surface obtained until a sprayed metal layer of the desired thickness has been built up, and sub sequently separating said sprayed metal layer from said mold model.

2. A method as set forth in claim 1 wherein said polyamide is applied to said mold model as a solution in an organic solvent which is thereafter volatilized, thereby forming a thin, continuous, uniform, smooth coating of said polyamide accurately reproducing the surface of the mold model.

3. A method as set forth in claim 1 wherein said polyamide has a softening point of at least 300 F.

4. A method as set forth in claim 1 wherein said polyamide has a softening point of at least 300 F. and is applied as a solution in a solvent comprising a lower aliphatic saturated monohydric alcohol which solvent is thereafter volatilized.

5. A method as set forth in claim 1 wherein said mold model is of rubber and wherein said polyamide protects said rubber against thermal decomposition and causes substantially more rapid adhesion of the molten metal spray and formation of a smooth, unbroken surface of sprayed metal over the rubber mold model.

6. The method which comprises spraying molten metal upon a mold model having over a substantial area thereof which is to be reproduced a thin, continuous, uniform, smooth surface coating of a synthetic linear condensation polyamide until a sprayed metal layer has been built up upon said surface coating, and subsequently separating said sprayed metal layer from said mold model.

7. The method of claim 6 wherein said polyamide has a softening point of at least 300 F.

8. A method of making a sprayed metal mold which comprises coating a porous mold model with a thin, continuous, uniform, smooth coating of a synthetic linear condensation polyamide, spraying molten metal upon the polyamidecoated surface obtained until a sprayed metal layer of the desired thickness has been built up, subsequently applying a solvent for said polyamide to the polyamide coating through the porous mold model and thereby softening said polyamide coating, and separating said sprayed metal layer from said mold model.

9. A method as set forth in claim 8 wherein said solvent is a lower aliphatic saturated monohydric alcohol.

10. As an article of manufacture, a mold model, over a surface of said mold model a thin, uniform, unbroken, smooth coating of a synthetic linear condensation polyamide accurately reproducing said surface, and superimposed upon said coating a sprayed metal layer deposited directly upon said coating by a molten metal spraying operation, said metal layer being readily separable from said mold model as a result of the presence of said coating and also having a smooth unbroken surface adjacent said mold model as a result of the presence of said coating.

11. An article as set forth in claim 10 wherein said polyamide has a softening point of at least 300 F. and wherein said coating is deposited from a solution of said polyamide in a solvent comprising a lower aliphatic saturated monohydric alcohol which is volatilized after application of said solution and prior to the metal spraying operation.


REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,179,762 Schoop Apr. 18, 1916 1,688,645 Novotny Oct. 23, 1928 1,796,470 Meyer Mar. 17, 1931 1,813,880 Kraft July 7, 1931 1,928,712 Walsh et a1 Oct. 3, 1933 1,935,916 Ragsdale Nov. 21, 1933 2,024,840 Wright Dec. 17, 1935 2,171,599 Reid Sept. 5, 1939 2,293,571 Stossel Aug. 18, 1942 2,349,290 Loughborough May 23, 1944 2,368,296 Goran Jan. 36, 1945 2,388,701 Nefi Nov. 13, 1945 2,400,518 Kreber et al. May 21, 1946 2,416,041 Austin Feb. 18, 1947 2,440,965 Merril et al. May 4, 1948 2,459,896 Schwarz Jan. 25, 1949 2,479,598 Barber et al Aug. 23, 1949 FOREIGN PATENTS 0 Number Country Date 576,875 Great Britain Apr. 24, 1946

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1179762 *14 Nov 191418 Apr 1916Metals Coating Company Of AmericaMetallic coating and process of making same.
US1688645 *9 Feb 192623 Oct 1928John Stogdell StokesPrinting plate and method of making the same
US1796470 *12 Dec 192717 Mar 1931Frederick S MeyerMethod for making molds for inlays and crowns
US1813880 *6 Sep 19277 Jul 1931Goodyear Tire & RubberMethod of making molds
US1928712 *11 Jan 19303 Oct 1933Celluloid CorpMold and the process of making same
US1935916 *6 Jun 192821 Nov 1933Budd Edward G Mfg CoMetal die and method of making the same
US2024840 *18 Jun 193417 Dec 1935Edgar J WrightPrinting plate and method of making the same
US2171599 *7 Sep 19375 Sep 1939Metallizing Engineering CompanProcess of making negatives in metal of metal objects of substantially smooth surface
US2293571 *29 May 194018 Aug 1942Otto StosselProduction of spray metal negatives of models
US2349290 *1 Nov 194123 May 1944Goodrich Co B FMethod of improving the adhesion of nylon to rubber
US2368296 *29 Oct 194330 Jan 1945Allis Louis CoRotor construction
US2388701 *15 Jul 194213 Nov 1945Wallace NeffMethod and apparatus for constructing shell-form structures
US2400518 *9 Jun 194221 May 1946Printing Plates Res IncElectrotyping
US2416041 *21 Oct 194018 Feb 1947Du PontManufacture of coated fabric
US2440965 *19 Mar 19434 May 1948Wingfoot CorpImproved tank for hydrocarbon fuels
US2459896 *18 Jan 194525 Jan 1949George SchwarzSilver impregnation
US2479598 *10 Apr 194423 Aug 1949Barber Hiram LMethod of making metal molds
GB576875A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2816336 *12 Dec 195517 Dec 1957American Steel FoundriesSand mold containing a chill section and method of treating same
US2848774 *21 Jul 195526 Aug 1958Hudson Engineering CorpSectional molds
US2923041 *18 Jun 19562 Feb 1960Nalco Chemical CoMold release agents for use in die casting
US2992747 *11 Oct 195718 Jul 1961Pittsburgh Plate Glass CoProtection of surfaces
US3018540 *18 Nov 195730 Jan 1962Sealed Air CorpMethods for making embossing rollers
US3047934 *4 Feb 19597 Aug 1962Gen Tire & Rubber CoBonding nylon to steel
US3077647 *13 Jul 195919 Feb 1963Gen Motors CorpParting agent for sprayed metal shells and method for making such shells
US3082516 *3 Dec 195726 Mar 1963Union Carbide CorpFabrication of metal shapes
US3112539 *17 Nov 19603 Dec 1963Gen Motors CorpForming articles by arc plasma spraying
US3125787 *14 Feb 196124 Mar 1964 Method of producing large metal casting cores
US3159012 *25 Nov 19601 Dec 1964Gen ElectricPassive transpiration cooling system
US3183289 *15 Dec 196111 May 1965Budd CoMethod of making a positive face vacuum forming mold
US3204917 *16 Dec 19607 Sep 1965Owens Illinois Glass CoLayered mold
US3401736 *26 May 196417 Sep 1968Bridgestone Cycle Ind CoProcess for formation of non-abrasive refractory rubbing surface having high thermal conductivity by casting
US3457634 *29 Mar 196629 Jul 1969Sperry Rand CorpMethod for fabricating memory apparatus
US3476585 *17 Oct 19664 Nov 1969Weyerhaeuser CoProcess of forming coated wood products
US3570400 *18 Apr 196916 Mar 1971Wollmar Dick JMatrix material for molding duplicate printing plates
US3661198 *31 Jan 19699 May 1972Evenson Roger AApparatus for making pontic cores
US3692085 *8 May 197019 Sep 1972Stephans Larry CProcess for producing cores by microwave heating
US3751288 *23 Jun 19717 Aug 1973Dow Chemical CoSolidifying a thin layer of metal on plastic film
US3937267 *3 Jan 197410 Feb 1976Kabushiki Kaisha AkitaMethod of preventing fin occurrence during metal casting
US4027716 *7 Mar 19757 Jun 1977Metallgesellschaft AktiengesellschaftMethod for preparing a continuous casting belt
US4200975 *30 May 19786 May 1980Western Electric Company, IncorporatedAdditive method of forming circuit crossovers
US4562882 *29 Feb 19847 Jan 1986Alleluia Vincent VMethod of making a dental prosthesis
US5189781 *10 Jan 19922 Mar 1993Carnegie Mellon UniversityRapid tool manufacturing
US5383512 *24 May 199324 Jan 1995Midwest Research InstituteMethod for fabricating a substrate having spaced apart microcapillaries thereon
US5619785 *27 Feb 199515 Apr 1997Tambussi; William C.Method of making a metal casket
US5817267 *13 Nov 19966 Oct 1998General Magnaplate CorporationFabrication of tooling by thermal spraying
US6447704 *23 May 200010 Sep 2002Gmic, Corp.Thermal-sprayed tooling
US6786271 *2 Aug 20027 Sep 2004Fujitsu LimitedMetal object forming method utilizing freezing point depression of molten metal
US7044191 *25 May 200116 May 2006Mold-Masters LimitedMold material processing device, method and apparatus for producing same
US7350558 *3 Mar 20051 Apr 2008Grigoriy GrinbergMethod of venting a spray metal mold
US20030034145 *2 Aug 200220 Feb 2003Fujitsu LimitedMetal object forming method utilizing freezing point depression of molten metal
US20040011495 *25 May 200122 Jan 2004Jonathon FischersMold material processing device, method and apparatus for producing same
US20060086474 *3 Mar 200527 Apr 2006Grigoriy GrinbergMethod of venting a spray metal mold
US20110171396 *8 Jan 201014 Jul 2011Valerian PershinThermally sprayed metal coatings on wood or wood composite surfaces
DE3320902A1 *9 Jun 198328 Mar 1985Stachniss Vitus Prof Dr Med DeMethod of producing dental prosthesis parts, especially cast fillings, partial or full crowns
WO2004035856A1 *26 Sep 200329 Apr 2004Stephen Anthony NobleProcess for metal-coating wood
U.S. Classification164/14, 164/72, 164/19, 29/604, 164/131, 427/133, 428/458, 524/379, 164/46, 524/111, 29/DIG.390
International ClassificationB22C9/06, A61C13/34
Cooperative ClassificationB22C9/061, Y10S29/039
European ClassificationB22C9/06A