US2539564A - Process of extrusion - Google Patents

Description

Jan. 30, 1951 J. L. BARRETT 2,539,564

PROCESS OF EXTRUSION Filed March :51, 1947 3 Sheets-Sheet l 2, F/Gfl. j

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Patented 30, 1951 PROCESS OF EXTRUSION John L. Barrett, Bloomfield Hills, Micln, assignor to Detroit Gasket & Manufacturing Company, Detroit, Mich, a corporation of Michigan Application March 31, 1947, Serial No. 738,299

4 Claims. 1

This invention relates to an improved process of extrusion of material under pressure.

More particularly, it relates to an improved process for extruding linear shapes from billets of metal or the like.

The object is to provide an improved process of extrusion which minimizes the waste and scrap that results from conventional extrusion processes now employed to extrude linear metal shapes of constant cross section from a succession of metal billets.

In the extrusion of shapes from billets such as the well known extrusion of linear shapes of constant cross section from.metal billets it is now the conventional practice to place a heated billet within the billet container of an extrusion press and to exert pressure upon one end of the billet urging the opposite end of the billet against a die squeezing the metal of the billet through the die aperture as a linear shape of constant cross section. Such container is open at both ends. One open end is adapted to be closed by a die assembly which exhibits a die aperture opposite the open end of the container. Pressure is exerted upon that end of the billet remote from the die, as by the use Of hydraulic ram mecha nism. Such pressure urges the opposite end of the billet against the die and forces the metal of the billet through the die aperture as a continuous shape having the cross section of the die aperture.

In the carrying out of this process it is not desirable to advance the ram mechanism sufficiently to extrude all of the billet material from the pressure chamber through the die because this would require bringing a part of the ram mechanism up against the face of the die which would necessitate most accurate control of the movement of the ram mechanism to prevent injury to the die. It is therefore the customary practice to stop the advance of the ram mechanism in carrying out the extrusion operation before all the material of the billet has been extruded. The advance of the ram may be stopped one-half inch or whatever distance is desired away from the die.

This stopping of the advance of the ram before the extrusion of all of the material of the billet is completed, leaves a residue of each billet in the container after each extrusion operation. Such residue is in the form of a flat disc of metal having the cross sectional shape of the container and is termed a heel" or butt. Upon withdrawal of the ram from the container such heel salvage. According to present conventional procedure the heels which result from a succession of such extrusion operations are collected and returned to the foundry for remelting into billets. As the metal billets are of relatively short length, such salvage constitutes a substantial portion of the original billet material and the addition to the cost of the extrusion by the salvage requirement is substantial.

The object of this invention is to eliminate such waste and additional cost of salvage. The object of this invention is to so carry out the extrusion of a succession of billets that this residue or heel pieces will be used up in the process and remelting of the same into new billets before extrusion thereof will not be necessary.

Following the extrusion operation performed on the first billet in a run the heel piece residue thereof is employed together with the succeeding billet in the run in the extrusion of such succeeding billet. Such practice is pursued with all succeeding billets and as a consequence all the heel pieces except the last one are utilized during the run. Such heel piece or disc is placed within the container between the end of the succeeding billet and the follow block of the ram mechanism. The ram pressure is then exerted through such heel upon the end of the billet being extruded. It is therefore feasible to extrude in one operation substantially all of the material of such succeeding billet through the die. Therefore, following the extrusion of the first billet, practically all of the material in each succeeding billet is extruded at the operation thereon. The heel piece or residue disc resulting from the extrusion of a billet has a rough or feather edge formed thereon during the extrusion operation and preferably such edge is trimmed off and such heel piece is cut down to a size to facilitate its insertion into the container while fitting snugly therein.

The above objects and others together with various advantages of the invention will more fully appear from the following specification, claims and accompanying drawings wherein is illustrated that portion of a conventional extrusion press required to set forth the invention and in which:

Fig.1 is a sectional view through the billet container and die mechanism of a conventional extrusion press showing a billet in place preparatory to receiving the pressure of the ram,

Fig. 2 is a sectional view taken on the same is removed from the container and constitutes line as Fig. 1 showing the ram' acting upon the aeaasea.

3 1 billet and illustrating an intermediate stage of the extrusion,

Fig. 4 is a sectional view taken'on the same line as Fig. 3 showing the billet container and die assembly moved apart and the follow block and billet heel being sheared off the face of the I die,

Fig. 5 is a vertical sectional view through a coin press showing the billet heel being resized for subsequent use,

Fig. 6 is a cross-sectional view taken on the same lines as Figs. 1 through 4 illustrating my invention and showing a billet located within the container and a trimmed billet heel and follow block in position to be urged by the ram against the end of such billet.

Fig. '7 is a cross-sectional view taken on the same line as Fig. 6 showing the ram at the end of its stroke upon the completion of the extrusion of the metal of the billet,

Fig. 8 is a cross-sectional view taken onthe same line as Fig. 7 showing the billet container and the die assembly moved apart and a shear member in position to shear the heel and follow block from the face of the die.

This improved process is adaptable for use with conventional extrusion machines. It is designed as hereinabove indicated to reduce the.

cost of extruding metal from a succession of billets. This is accomplished by so carrying out the process that substantially all of the material of each billet following the first one in the run is used up during the operation thereon. The drawings illustrate those parts of an extrusion press necessaryto illustrate the invention. 1

A billet container or pressure chamber of standard press mechanism is indicated by the numeral ll. Located within the chamber of the container is a metal billet l2. This type of extrusion is adaptable for use with soft metals and those which are capable of extrusion at low temperatures such as lead, tin, aluminum and suitable alloys. It indicates a hardened follow block and I. a ram, which ram may be actuated in any suitable manner as by hydraulic mechanism (not shown) to urge the follow block against the end of the billet. The follow block is designed to form a close fit within the billet chamber. The ram is of smaller diameter so as to work freely. The billet container or pressure chamber i0 is open at both ends as shown.

A die assembly which carries a die element is adapted to be disposed at one open end of the billet container. This die assembly is here shown as comprising a die head 18, die ring adapter 20, die ring 22 and die 2!. Included within the assembly is a die backer 26, bolster 28 and bolster adapter 30. Associated with the die assembly and backing up the same is a platen ring adapter 32 and platen ring 34.

The construction of a conventional press is such that either the die assembly and associated parts can be moved against one end of the billet container and locked in such position or the billet container can be moved into juxtaposition with the die assembly. The die proper 24 closes the open end of the billet container and exhibits a die aperture through which the plastic material of the billet is extruded as a length of material 4 exhibiting a constant cross section determined by the die aperture.

The billet is heated to a temperature which will insure the extrusion of its material through the die aperture upon the application of the pressure of the ram thereagainst. Such temperature will depend upon the particular material being used. Aluminum may be heated to a temperature of 750 to 1000 F. and under the pressure of the ram the metal can be flowed through the die aperture. The billet is heated to such temperature before being placed in the billet chamber After the billet l2, suitably heated to the required temperature, has been placed within the bidet container l0 and the die assembly located in position as shown in Figs. 1, 2 and 3, a follow block ll which is of hardened metal and formed to a size to present a snug fit within the billet container is positioned ahead of the ram I6 and urged by such ram against the end of the billet. In Fig. 2 the ram is shown as urging the follow block against the end of the billet and extruding through the die aperture material of the billet in a linear shape identified by the numeral 38.

The length of the stroke of the ram is short of that required to extrude all of the billet material because it would be undesirable to press the follow block directly against the face of the die and it is not commercially feasible to control the movements sufilciently accurately to extrude all of the billet material without danger of inluring the die by urging the follow block thereagainst. The completion of the stroke of the ram therefore leaves a butt or heel section 40 of the billet as shown in Fig. 3. This heel section serves as a cushion for the follow block and ram and prevents any injury of the die by them.

Upon the completion of the stroke the ram is withdrawn as shown in Fig. 4 and the die assembly and billet container are separated. Following this separation the follow block it and butt section 40 are sheared off the face of the die. A conventional shear member 42 is illustrated in the several figures of the drawing. The process described to this point is conventional. My invention consists in the employment of the billet .butt or heel section 40 as hereinafter set forth. The billet butt following an extrusion operation carries a rough or feather edge 4! (Fig. 4) and has been expanded in diameter. According to one embodiment of this invention, after the heel and follow block are removed from the face of the die as shown in Fig. 4, the heel 40 is separated from the follow block I4 and trimmed of this rough edge and cut down to its original size. This cutting down to the proper size may be accomplished in a coin press such as shown in Fig. 5 wherein the billet butt 40 is shown as located within a chamber 46 and a ram 44 is illustrated as acting upon the billet butt to force it through the interior of the press.

When the billet butt has been shaped to the upon the billet I2 within the chamber but through this butt 40 upon the billet. Upon the completion of this stroke of the ram substantially all of the material of the billet l2 will have been extruded. The billet butt 40 will form a cushion between the follow block and the face of the die and prevent contact of the follow block with the die. This is shown in Fig. 7 of the drawing.

Upon completion of this stroke of the ram the billet container and die assembly are again separated as shown in Fig. 8 and the follow block l4 and billet heel 40 are again sheared off. The billet heel resulting from this operation may then be trimmed and utilized in carrying out of a subsequent billet extrusion operation.

Another satisfactory embodiment of the process has been found to be to leave the billet heel 40 attached to the follow block it as it falls away from the die as shown in Fig. 4. Without trimming of the heel such heel and the follow block may be interposed together between the ram and the end of a succeeding billet l2 and thus utilized. It has been found feasible to urge the untrimmed heel 40 ahead of the follow block it into the bore of the container to accomplish the extrusion of the billet.

As here shown and described, the billet heel is interposed between the end of each billet subsequent to the first one and the follow block. Such billet heel might, however, be placed in the billet chamber ahead of the billet. By the provision of means for withdrawing the follow block II with the ram rearwardly through the chamber the billet butt 40 remaining from one extrusion operation might even be left within the chamber for the succeeding billet extrusion operation.

What I claim is:

1. In the extrusion of a linear shape from a metal billet through advancing ram means against one end of a billet disposed within a container urging the opposite end of the billet against die means at the opposite end of the container and extruding the billet metal through the die aperture, that process which includes stopping the extrusion of the billet metal while there is an unused billet heel remaining, trimming said heel to fit within the container and utili zing said heel in the extrusion of another billet by placing it between the end of such other billet and the ram means and extruding such other billet metal through the die aperture by pressure of the ram means against said heel.

2. In the extrusion of a linear shape from a metal billet through exerting pressure upon one end of a billet disposed within a container and extruding the billet metal through a die aperture, that process which includes stopping the extrusion of the billet metal while an unused heel of the billet remains, trimming said heel to fit within the container, and utilizing said heel in the extrusion of another billet by placing it at one end of such other billet within the container and thereafter extruding the metal of such other billet.

3. In the extrusion of a linear shape from a metal billet through advancing ram means including a follow block against one end of a billet disposed within a container urging the opposite end of the billet against die means disposed at the opposite end of the container and extruding the billet metal through the die aperture, that process which includes stopping the extrusion of the billet metal while there is an unused billet heel remaining, removing said billet heel and follow block, separating the heel from the follow block and trimming the heel to fit within the container and utilizing said trimmed heel in the extrusion of another billet by placing it between the end of such other billet and the follow block and extrudingsuch other billet metal through the die aperture by pressure of the follow block thereon through said heel.

4. In the extrusion of a linear shape from a metal billet through advancing ram means including a follow block against one end of a billet disposed within a container urging the opposite end of the billet against die means disposed at the opposite end of the container and extruding the billet metal through the die aperture, that process which includes stopping the extrusion of the billet metal while there is an unused billet heel remaining, removing said billet heel and follow block and placing said heel and follow block against the end of a succeeding billet disposed within the container and extruding the metal of such succeeding billet by exerting pressure thereon from the follow block through said heel.

JOHN L BARRETT.

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

UNITED STATES PATENTS Germany Oct. 15, 1936

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