US2182775A - Method of making dies - Google Patents

Description

Dec.4 12, 1939. P. c. ABOU'cHAR' 2,182,775 l METHOD 0F MAKING DIES K 1 Filed March 17, 1937 2 Sheets-Sheet 1 lNvENToR 64M C Hanan/4f? Dec. l2, 1939. P. c. ABOUCHAR I METHOD 0F MAKING DIESl Filed March 17, 1937 2 Sheets-Sheet 2 Passed Dec. 12,1939

raul c. sbouclm, Brooklyn, N. Y.

Applica-tion March 17, 1937, Serial N0. 131,315 Renewed March 4, 1939 s claims. (ci. zoe-s) This invention relates to the manufacture oi dies for use in casting or molding various kinds Aand classes of materials; and the object of the invention is to provide a method of forming one or `a number of diesv from a pattern or model of `a predetermined articleto be produced or from a produced article in the operation of forming a die to accurately reproduce such article; a further object being to-provide a method or process of the class' described which consists in rst making plaster casts of the pattern lol' article to be reproduced by the casting of the resulting dies or the separate parts thereof, then electrodepositing copper on one surface of each plaster cast to form la replica of opposed surfaces of the article to be formed, then `utilizing the copper ,elements formed as a pattern or mold and electrodepositing iron on one surface thereof to form an iron die or die parts of the desired contour capable of reproducing the original pattern or sample; a further object being to provide means for reinforcing and backing the resultant iron dies to adapt them for predetermined uses'in making die castings; and with these and other objects in view, the invention'consists in the method or process of diemakingas more fully hereinafter described and claimed. The vinvention is fully disclosed in the following specification, of which the accompanying drawings form apart, in which the separate parts of my improvement are designated by suitable ref.- erence characters in each of the views, and in which y Fig. 1 is a perspective and sectional view of 85 ii. suitable frame or mold employed in making thev original plaster casts with thepattern or sample to be arranged therein shown inan extended position and also showing parts of the 'construction broken away and. in section. 4o Fig. .2 is a section onthe line 2-2 of Fig, 1, with the parts assembled.

Fig. 3 is s viewsimilsr toting-.11, illustrating the next successive steps in the formation of the' plaster casts.

Fig. 4 is a sectional view similar 'to Fig.; of.

the structure shown 3 and illustrating the resulting Plastercasts.

. Fig. s is s perspective view illustrating the' V-li'eiirt step in the process which I employ.

5 Fig. s is s section-on the une e-eef'rig. s.-

.is a perspective view of a. part of the structure shown in Fig. 6, detached.

t Fig. 8 lis a sectional view through the mold,

u showing the next step in the process of forming therst methods in the steps o f Iforming a back-- as the pattern piece.

`provided with a recess or depression I4 in then .walls I'I which may be of any d'esired shape or contour and of dimensions suitable for controlling I or substantially controlling the peripheral contour ofthe finished die to be formed. The plate the same, indicating the flnishediron olf steel deposited in dotted lines.

Fig. 9 is a view similar to Fig. 8, illustrating ing for the die. 5 Fig. 10 shows the" completed die or one part thereof made according tothe invention; and

Fig. 11 is a cross sectional' view through part. of a complete die or the separate parts thereof, n made according to my invention.

' In carrying the invention into effect, I may construct in any suitable manner an article to be produce'd or what may be termed a pattern of such article, or insome cases where it is desirable to reproduce an article previously made '15 in any desired manner, I may use such article In'theaccompanying drawings, I have indicated at l2 a pattern piece or article in the form of a tray-'or dish, the bottom wall i3 of which is 20 form Vof a star to give ornamentation o r design to the tray. The .rst step in' the process consists in v providing a plaster mold i5 in the form of a bottom plate i6 and upwardly extending ,side 25 I6 is provided with an aperture i8 which ilts 30 snugly around the peripheral walls of'the pattern i2 as clearly seen in Fig. 2 of the drawings. The

plate is also preferably providedwith a raised wedge member I9 for forming-a gate in the finished die when 'such gates are desirable. How- 35 ever, 'in some uses of the invention, the gate is not essential and this is especially true in mak.- ing castings ofv Bakelite or similar thermo-setting plastic materials, whereas in the die castingl of metals, thermoplastics and other materials, 40, the gate is desirable. The sizeand contour of the gate will depend entirely upon the construction of the die, and in the present drawings the 'illustration throughout is purely diagrammatic.

It desired, alining pins 2l may also protrude 5 fromthe upper surface ofthe plate il to provide proper alinement between the plaster casts to be ',lnade.- After the parts have been assembled as seen in Fig. 2.o! the drawings, a body of molding material or plaster` ofParis is placed `in the n fiiisiie il and aperiect or substantially perfect f impression will be taken of theinner surface Ila o i the pattern I2., After this plaster cast is made,

the same neingfdesi'sneted st zi inrigs. s, 4 of' 'the drawings, this cast is placed in' another frame 55,

|5a, substantially similar to the frame l5, and the pattern |2is arranged upon the molded portion 22 of said cast and alinement pins 23 .are placed in the apertures of the cast 2| and project upwardly into the chamber of the frame lia. A gate forming piece lila is arranged in the gate recess 24 formed in the cast body 2| by the member I9 and projects above the surface of the plaster cast 2| so as to form a similar recess 24a in the secondplaster cast 25 which has a mold recess or impression 26 conforming with the outer walls I 2b ofthe pattern piece i2.

Prior to forming the plaster cast 25, two thin strips of ribbon or fabric 2l are arranged upon the upper surface of the body 2| adjacent two edges thereof, and the upper surface of said body will be coated with a suitable material to prevent adhesion of the plaster cast 25 therewith. When the body 25 becomes setand hard, the same is removed by the aid of the strips 2l. After removing the pattern i2 and the part |9a as well as the pins 23, two bodies 2| and 25 will remain and these bodies are treated through a series of steps in theformation of the resulting molds or dies.

In order to illustrate, the invention, the further steps of the process will be applied to the plaster body 2i only, it. being understood that similar steps are employed in conjunction with thebody `25 in forming the two resulting die or mold parts.

The next step in the process consists in coating the entire body 2| with shellac, lacquer or similar materiai.which is allowed to dry, after which a thin coating of lacquer is then applied to the surface Zia of the body 2i. Before this coating is dry, necopper powder ori graphite is brushed thereon to form an even, continuous metallic or graphite surface'. I then attach two copper wires 28, 29 to the body 2i and over and in contact with the treated surface 2|a, after which theentire body 2|, except for the surface 2l a between the wires 28 and 29 and inwardly of the upper and lower edges 30 thereof are coated with wax or other suitable non-conducting material, as is indicated at 3i in Fig. 6 of the drawings. The body 2| treated and prepared as above described is now placed in a copper electrodepositing or electroplating bath for a sufilcient length of time to produce the desired deposit of copper upon the surface 2| a, which will be in the form of a relatively'thin shell. as seen at 32 in Fig. 'l of the drawings, which is also indicated in cross section in Fig. 6 of the drawings. 'Ihis shell 32 is then removed from the body 2|. It will be understood in this connection that any other types of metal deposits may be formed in the manner of the copper deposit which would be suitable for the purposes herein named, or, if desired, 'a metallic cast maybe made on the plaster or other molded body.

vThenextstepoftheprocessconsi'stsinarrangv ing asuitable backing upon the surface 32a of the copper'shell 32, and t backing may bein the form of a body of plasterof Paris 33 or abody of wax, lead or thelike suitably molded thereon, or. if desired, may consist of a body. of low melting leadalloy, soldered or otherwise secured to'the surface 32a of the shell 32. In some cases. the backing may not be necessary. but this would depend largely upon the thickness of the shell or the design of the moldrcavity therein, or the backing maybe applied before the shell 32 is removed from the body'2l. In any event, the rear surface of the shell 32a or the backing 33 is then coated-with lacquer or other suitable non-conductive material 34.4 Twowiresarearrangedtocontacttheinner surface of the shell 32 and the surface 32h of the shell is then polished or brushed to a perfect smoothness by any suitable means after which the next step in the operation is performed.

The next step of the process consists inplacl ing the shell 32 treated and prepared as above stated in an iron electrodepositing or an electroplatng bath a vsuficient length of time to form on the surface 32h of the shell 32 a deposit of iron or steel as indicated in dotted lines at 36 in Fig. 8 10 of the drawings. The surface 36a of the deposit adjacent the surface 32h of the shell 32 will be a perfect or substantially perfect reproduction of the surface 32h, whereas, the surface 36h will be rough or irregular.

In the production of molds or dies of various kinds and classes, the degree of time for the iron deposit will be varied to suit the conditions to which the die or mold is to be subjected. In other words, the thickness of the deposit will be varied to give the required strength and'vrigidity to the resulting die or mold. After the desire'd deposit has been formed as at 36, the same is removed from the bath and stripped from the shell 32 and this deposit 36 forms, in so faras the surface 36a is concerned, one half of the resulting die or mold to be used in making moldings or castings as heretofore stated. The die 36 may be heat treated, annealed, tempered or otherwise prepared for giving it the required strength i'n the respective uses to which the same is to be applied. The die or mold 36 may be trimmed to a finished contour and the surface 36a thereof treated in any desired manner to provide the proper finish or polish thereon. At the Sametime, the surface 36h may be finished in such manner as to suit it for the particular use to which the die is subjected. In

some cases, a suitable backing may be cast or molded thereon or a finishing plate may be attached thereto. However, in some uses and especially where the die or mold parts are subjected to heavy pressures, it would be desirable to provide a very accurate backing for the rough or irregular surface 36h. In this case, I proceed as follows.

The surface 36a of the die part 3i is coated with a suitable non-conducting material as indicated at 31. Electric wires 38 are attached tothe die and a copper shell 39 is formed on the surface 33h of the die by copperelectrodepositing the same thereon in the manner of forming the shell 32. After the copper shell 39 has been formed and before removing the same from the die 33, s low melting point alloy, preferably of lead, is soldered onto the outervsurface 39a of the shell 3l to form a suitable backing body Il asgindicated in dotted linesin Fig. 9 of the drawings, after which the shell 33 including the backing 4I isremoved from the die and a casting of iron, steel or other material is made therefrom.

Ihm-mand 11 ofthedrawingsIhave shown such resulting casting at Il. -The surface Ila is of a contour similar to the contour of the surface bof the die 33, thus providing an accurate or substantially accurate backing for said 66 die. In some instances, the copper shells 3l with a suitable backing body as at Il, which may be in the form of an alloy or a cast of 'some other materiahmaybeusedasaiinishorbackingin the me of the die 33. Itis onlywhere the'die 70 issubjectedtoheavystressesbrstrainsor excessive pressures, that backing similar to the backing Il is required. It understood that the dies may be actuated hydraulically or pneumatically, in which latter event, the contour Il backing applied to the die 42 which is similar f to the backing 4|. At M is shown the gate giving admission. to the impression or mold chamber 45 between adjacent surfaces of the mold or die parts 36 and 42, which impression or mold chamber conforms with and will produce in the resulting casting or molded part formed therefrom an'article which .would be anv exact or substantially exact reproduction of the pattern piece Where it is desirable to make a number of similar dies or molds,.any desired number of the same may be produced fromthe shell 32 including its backing 33 as shown in Fig. 8 of the drawings. lIi' desired, these dies or molds may be lassembledin a suitable frame and a single unitary backing similar to the backings Il, 43 or the backing 40 formed therefor. In some cases, the individual die parts may be fitted orset in predetermined receptacles in a multiple die holding plate or body, the die or the backing therefor being shaped to fit accurately in such plate or support.

With a process of the class described, accurateor substantially accurate reproductions of a predetermined article or a pattern of an article may be produced from a die formed in the man-v Vner described or from amultiplicity'of dies produced in this manner, in which event, all of the castings willbe identical, notwithstanding the fact that they are made from a multiplicity of independent die units in what is commonly termed a multiple impression die. Replacement or renewal of dies may be made from time to l time at a very nominal cost, and in fact, the cost of producing the original dies is economical asv compared with present methods of preparing dies or molds of the kind under consideration.

Instead of depending upon the accuracy of a workman, an accurate reproduction ofthe article or pattern piece I2 is assured by my process.

My invention will ndits special usefulness in the preparation of the dies or molds in the art of making thermo-setting castings of Bakelite and similar thermo-setting materials as wellv as in'theart of die casting metal alloys and thermoI plastic materials, it being also understood that the dies may be used for forming or shaping certain kinds andclasses of materials in the manner of stamping and sheet metal forming dies now in general-use, and especially-wherethe tensilev strength of the die is notan essential factor as would be the case in working heavy sheet metals or ln punching or stamping metals.

therebetweenconsist of electrodeposited iron,

'My invention not only consists in the process of producing die or mold parts' as herein specifically', described, but also in a novel con-A struction of die or Amold parts wherein adjacent surfaces of said die or mold parts includingthe walls of the impression or mold chamber formedl thus producing a fine grade of dieor mold parts, especially due to the fact that'only the better types f metals are suitable in this type of'conl struction. n Where the dies or mold parts lare utilized in the formation of die castings, suitable means of circulating water-or other cooling r agents through the die parts will be provided. If desired, these passages may be formed between the iron die facings and their backings or formedonly in the backings.

Having fully described my claim as new and desire to secure by Letters Patent, is:

1. A die or mold of the class described coniprising at least two parts with an impression or mold chamber formed between adjacent surfaces of saidparts, each of theopposed walls of the mold chamber being female exact reproductions for the surfaces of the article to be produced, and the walls of the impression or mold chamber of said die parts consisting of electro-deposited iron vhaving finished hardened surfaces.

2. A die or mold of the class described comprising at least two parts with an impression or mold chamber formed between adjacentl surfaces of' said parts, each of the opposed walls of the mold chamber being female exact reproductions for the surfaces of the article to be produced, the

adjacent walls of the die parts including the impression or mold chamber thereof consisting of electrodeposited iron having finished hardened compression surfaces, said walls including a.A backing of reinforcing and strengthening material, and said backing beingY of predetermined contour.

3. lThe process of constructing dies of the class described which consists in taking a predetermined object to be reproduced from the dies, rst making plaster casts of the separate side surfaces of said pattern, then` forming a die from each plaster cast by first producing electrodeposited copper shells on the impressions of said plaster casts, removing said shells from the plaster casts, then electrodepositing iron on the impressionsurfaces of said copper shells, and 'then stripping on the copper shells to form the re- 40 v sulting metal dies, each having an accurate female impression of one side surface of the original object employed.

4. The process of constructing dies of the class 4described which consists in taking'a predeter- 45 Iolif the copper shells to form the resulting metal dies, each having an accurate female impression of oneV side surface of the original object employed, and applying a suitable backing to'the copper shells prior to forming the electrodeposf ited iron thereon.

5. The process of constructing dies of the class so decribed which consists in taking a predetermined object to be reproducedfrom the dies, iirstmaking plaster casts of the. separate side l surfaces of said pattern, then forming a die fromeach plaster cast by flrstproducing electrode-'65 posited copper shellsvon the impressions of said plaster casts, removing sald'shjelis from the plaster casts, then electrodepositing iron on the-impression surfaces of said copper shells, then lstripping od the copper shells to form the re- '10 sulting` metal dies, each having an accurate, female'impression of one side surface of the orlginal object employed. and then applyini! suitable reinforcing.A backings to the dies to nish and give predetermined contour thereto.

invention, what I 5- pression surfaces of seid copper shells. then stripping ofi.' the copper shells to form the resulting metal dies. each having an accurate female impression of one side surface of the original object employed, and suitably treating the impression surtaces of the dies to nnish and harden such surfaces.

PAUL C. ABOUCHAR.

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