US2698684A - Extrusion - Google Patents

Description

3 Sheets-Sheet l Jan. 4, 1955 K. B- GUINEY ETAL EXTRUS ION Filed March 23 1949 1955 K. B. GUINEY ETAL 2,698,684

EXTRUSION Filed March 25, 1949 3 Sheets-Sheet 2 United States Patent EXTRUSION Karl Burke Guincy and Carl Richard Anderson, Lafayette, Ind., assignors to Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Application March 23, 1949, Serial No. 83,078

3 Claims. (Cl. 20717) This invention relates in general to improvements in extrusion die structures and apparatus of the general type described in United States Letters Patents 2,135,194, issued November 1 1938, to Wyvel S. Underhill, and 2,164,397, issued July 4, 1939, to John E. Ganoe.

The invention is more specifically concerned with the provision of extrusion die structures for the production of semi-closed and tubular sections or shapes in indeterminate length from solidified billets of metal, or similar materials, wherein the material of a confined billet is forced or die-expressed under pressure through a die orifice formed between a mandrel and an exterior configuration controlling die aperture.

It has been our general observation that extrusion die structures of the general type disclosed in the aforementioned patents require extremely high pressures to force the material of a billet through the passage or passages in the adapter supporting the stub mandrel adjacent the die aperture in the exterior configuration controlling die. Such extreme pressures are explainable when it is considered that a dual extrusion operation is being performed to first reduce the starting billet to the form and size required to pass through the adapter, followed by a second extrusion operation to force the material of the billet through the die orifice formed between the mandrel and exterior configuration controlling die aperture to produce the finally desired shape or section.

The die structures and apparatus of the present invention introduce certain new and novel features of construction which have not been heretofore recognized or employed in extrusion equipment of the general type incorporating adapter and/or bridge supported mandrels in combination with a female or exterior configuration controlling die aperture. For example, the die structures contemplated within the scope of the invention employ a single or cantilever support for the mandrel and otherwise provide unobstructed axial flow or passage of the material from a billet to a major portion of the die orifice under the influence of applied extrusion pressure. In addition to the cantilever support for the mandrel, the die structures of the invention provide a relatively flat substantially unobstructed frontal area in the plane of entry to the die orifice, forwardly of which projects a buttress structure for supporting the mandrel and generally reinforcing and strengthening the die structures.

It is an object of the invention to provide a structurally strengthened extrusion die structure for the production of semi-closed and tubular shapes or sections.

Another object of the invention is to provide an extrusion die structure that is characterized by unobstructed axial flow or passage of material to be extruded from a billet or' mass of the same towards and through a die orifice.

A further object of the invention is to provide an extrusion-die having a buttress supported mandrel in which the buttress extends forwardly of the die orifice and is offset with respect to axial flow or passage of the gmterial to be extruded towards and through the die ori- Other objects and advantages will present themselves to those skilled in the extrusion art on consideration of the following description of several embodiments of the invention, which are hereinafter explained in terms of the several drawings, in which:

Fig. 1 represents a top plan view of one embodiment of an extrusion die constructed in accordance with the principles of the invention;

Fig. 2 represents a front elevational view of the die illustrated in Fig. 1;

Fig. 3 represents a side elevational view of the die illustrated in Figs. 1 and 2;

Fig. 4 represents a perspective view, partially sectioned and to slightly larger scale, looking into the front face of the die of Figs. 1, 2 and 3;

Fig. 5 represents an end elevational view, to enlarged scale, of a semi-closed extruded shape or section produced by the die structure of Figs. 1 through 4;

Fig. 6 represents a sectional elevational view through an extrusion cylinder and tool assembly incorporating the extrusion die structure of Figs. 1 through 4, the extrusion die having been sectioned along the plane VIVI on Fig. 2;

Fig. 7 represents a front elevational view of a second embodiment of extrusion die structure incorporating a bolted unitary structure for the production of tubular sections;

Fig. 8 represents a partial sectional side elevation of the die of Fig. 7;

Fig. 9 represents an end elevational view of the extruded section produced by the die of Figs. 7 and 8;

Fig. 10 represents a fragmentary top plan view taken in the direction of the arrows XX on Fig. 7;

Fig. 11 represents a third embodiment of extrusion die structure in top plan view;

Fig. 12 represents a front elevational view of the die illustrated in Fig. 11;

Fig. 13 represents an exploded view in side elevation andi partial medial section of the die structure of Figs. 11 an 12;

Fig. 14 represents an end elevational view of a die insert removed from the structure illustrated in Figs. 11 through 13;

Fig. 15 represents a sectional elevation taken along the plane XVXV on Fig. 14; and

Fig. 16 represents an end view, to enlarged scale, of an extruded tubular section or shape produced by the die illustrated in Figs. 11 through 15.

Turning to the drawings for a more specific description of the invention, reference is made to Figs. 1 through 6 for one embodiment of extrusion die structure or apparatus that falls within the scope of the invention. Therein 10 represents a die body provided with a forwardly projecting abutment 12 that occupies substantially one half of the lower portion of the die body 10. Above the abutment 12, the front face of the die body or block 10 presents a relatively flat frontal area within the plane of which a die orifice 14 is machined or otherwise formed. The die orifice 14 is bounded on its interior surface by a mandrel head 15 that is integrally supported on the abutment 12 by means of a connecting buttress 16.

The die orifice 14 is relieved at 18 (Fig. 6) to reduce unnecessary frictional engagement on the shape being extruded, and lateral reinforcing buttresses 20 may be provided on either side of the central mandrel supporting buttress 16 to increase the strength of the die.

It is to be observed that this embodiment of the invention has been designed for the production of semiclosed extruded sections, such as illustrated at Fig. 5, and that the die has been preferably constructed in one piece from a single forged block of suitable tool steel.

It will also be noted, on reference to Fig. 6, that the die structure is assembled within a tool ring or die holder 22, keyed against rotational movement therein by means of keys 24, which is provided with an inturned lip or chamfered surface for engagement with a complementary chamfered surface 26 on the die body 10. Die holder 22 is supported within a tool carrier 28 which is constructed in the form of an open top semi-circular channel having an inwardly turned flange 29 in engagement with not more than one-half the circumference of an outwardly extending flange or shoulder 30 on the tool ring 22.

Tool carrier 28 has a flange 31 integrally formed or secured thereto at its end removed from the semi-circular Flange 29. The distance between the oppositely disposed faces of flanges 29 and 31 is such that the tool ring 22, and its die assembled therein, can be lowered downwardly through the open top channel section of the tool carrier 28 and then advanced to the left, as viewed in Fig. 6, to bring the shoulder 30 against the inner surface of flange 29. Following this assembly operation, one or more back-up blocks 32 are lowered into the open top channel to substantially fill the space between the inner surface of tool carrier flange 31 and rear face of the extrusion die and tool ring 22. A key 34 is usually employed for axially aligning the tool holder 22 and back-up block or blocks 32 within the tool carrier 28. Also, the back-up block or blocks 32 and tool carrier flange 31 are provided with suitable internal bores or apertures to accommodate a wide range of extruslon dies assembled therewith.

Tool carrier 28 is preferably reciprocally mounted within a cavity in the main press platen 35, a suitable lock ng bar arrangement 36, extending through the platen, serving to maintain pressure resistant relationship between the extrusion die and the billet cylinder 38. In the specific assembly illustrated in Fig. 6 the extrusion die body is provided with a chamfered surface 40 that engages and seals upon a complementary chamfered surface on the billet liner 42.

From the above description of this embodiment of the invention, illustrated in its structural features and assembly in Figs. 1 through 6, it will be noted that the extrusion die seals upon the discharge end of the billet cylinder 38 with the die abutment 12, mandrel buttress 16 and lateral buttresses 20 extending forwardly into the billet cylinder. It is to be further noted that pressure applied from the left, as viewed in Fig. 6, upon a billet or mass of material confined within the cylinder 38 will cause the material to be extruded to advance into abutting relationship with the relatively flat frontal area of the die body 10 without interruption by any form of obstruction that would interfere with direct axial flow of the material from the cylinder forwardly towards and through the die orifice 14. Abutment 12 and buttresses 16 and 20 are strength providing elements insofar as the extrusion die structure is concerned, the forwardly extending axial length of the abutment 12, and its integral attachment to the mandrel supporting buttress 16 over this length, as well as its integral attachment to the fiat front face of the die body 10 and mandrel head 15, resisting any tendency for the mandrel to shift, turn or tilt under applied extrusion pressures. This represents a sturdy die structure without resort to a bridging structure across the entire frontal area of the die proper. Also, the lateral buttresses alleviate the lateral flow of the material being extruded, which is known to exist during an extrusion operation, across the relatively flat area of the die body 10 in the vicinity of the central mandrel supporting buttress 16, which lateral flow exhibits a tendency to deflect a mandrel in respect to its cooperating die aperture. The abutment 12 entirely eliminates any lateral flow which could react upon the central buttress 16 and its unitary mandrel 15 because of its location forwardly thereof.

A second embodiment of the invention is illustrated in Figs. 7 through 10. In this form, the die structure has been designed to produce extruded tubular sections, such as illustrated in Fig. 9, and comprises a die body 45 having die aperture 46 machined or otherwise formed therethrough with the usual relief 48 provided beyond the actual die bearing.

Instead of constructing the die from a single forged steel die block, as in the first embodiment of the invention, the present die structure incorporates a separate mandrel element 50 formed integral with an abutment 52 and mandrel supporting buttress 54. The abutment is suitably drilled to accommodate an aligning dowel pin 53 and socket head cap screws 56, which are respectively received within a complementary dowel aperture and threaded apertures in the die body 45. By means of this construction the abutment 52, buttress 54, mandrel 50 abild die body 45 become a unitary die structure or assem- The die structure of Figs. 7, 8 and 10 is assembled with respect to an extrusion press in the same manner as described in connection with Fig. 6. The only difference in the operation of this die structure lies in the provision of an open space 55 on the underside of the mandrel 50 immediately adjacent and in direct communication with the die aperture 46. The space 55 is readily provided by undercutting the buttress 54 and it will be observed that the only portion of the die aperture 46 which is not accessible to unobstructed axial flow or passage of material from the billet or mass under extrusion is that represented by the bottom chord of Fig. 9 equivalent in length to the breadth of the mandrel buttress 54 overlying the same. Otherwise the same advantages accrue herein as stated for the first embodiment of the invention.

The third embodiment of the invention, selected for purposes of illustration, is disclosed in Figs. 11 through 16. Therein the extrusion die has again been constructed from separate elements, which are assembled into a unitary structure before use.

On reference to the drawings it will be seen that this embodiment of the invention comprises a die body 58 having an enlarged tapered bore 60 therethrough. Within the tapered bore 60 a female die insert 61 is press fitted, the die insert having the desired exterior configuration controlling aperture 62 formed or machined therein. As is customary, the die aperture 62 is relieved beyond its bearing, as at 64.

A mandrel 65 for cooperative association with the die aperture 62, and for controlling the interior configuration of the extruded shape to be produced, which in this instance is represented at Fig. 16, is supported by a buttress 66 integrally formed with the mandrel and an abutment 68. The underside of the buttress 66 is relieved at 70 to provide the necessary open space for coalescence of the material being extruded adjacent and in communication with the die aperture 62 adjacent the bottom chord of the section to be produced. Suitable cap screws extending through the die body 58 into threaded engagement with threaded apertures in the abutment 68 serve to unitarily assemble the die structure in much the same manner as previously described in connection with the die structure of Figs. 7, 8 and 10. There is the additional provision in the instant die structure of undercut interengaging surfaces 72 and 74 on the abutment 68 and die body 58, respectively. These interengaging surfaces extend across the abutting faces of the abutment and die body, and in assembled condition serve as additional security against any tendency of the abutment 68 and die body 58 to separate or tilt out of alignment under the influence of applied extrusion pressures.

The same remarks apply for the third embodiment of the invention, insofar as its assembly with the billet cylinder of an extrusion press and its operation are concerned.

In the first embodiment of the invention the material under extrusion pressure is advanced through the die orifice formed between the mandrel 15 and die aperture 14 without any obstruction against axial flow or passage from the billet through the entire die orifice. The widths of buttresses 54 and 66, respectively, overlying the die apertures in the second and third embodiments of the invention. do obstruct axial flow or passage of material direct from the material in the extrusion cylinder towards and through the die orifice in each case in accordance with the width of each of the buttresses 54 and 66. Regardless of the shape or section to be extruded, it is a significant feature of the die structures and apparatus of the invention that a substantial portion of the die orifice, by which is meant at least 50 per cent thereof, which would be the case in the fabrication of a circular tube using extrusion die structures constructed in accordance with the invention, is unobstructed to axial flow directly from the material in the billet cylinder towards and through the die orifice.

It will be observed that the abutments 12, 52 and 68 of the unitary die structures above-described all form a stepped plane surface with the flat frontal face of the die blocks associated therewith, and that the abutments are otherwise confined to one side of the die apertures through the die blocks as well as to one side of a plane within which the stepped plane surface lies. This construction provides ready removal of the unextruded heel portion of the material undergoing extrusion, as more definitely explained in the following paragraph.

In all forms of the .invention, and at the conclusion of an extrusion operation, the tool carrier 28 is reciprocated away from the billet cylinder 38 to a location under a reciprocating shear, or saw (neither of which is shown), where the heel or butt of a previously extruded billet is severed from the die structure. The unextruded heel is made up of oxide and dross, in the case of metal and alloy extrusion operations, and is waste or scrap material. The severance of the heel is made in the plane of the front flat faces of the abutments 12, 52 and 68,

respectively, of each of the die structures, and in the absence of the adapters and bridge supporting members employed with the mandrels of the prior art, it is a relatively facile task to knock any remaining unextruded material that still remains around the mandrel buttresses 16, 54 and 66, respectively, beyond the plane of severance, by light hammer blows. This technique, which is a direct advantage attributable to the extrusion dies of the present invention, reduces the time required to prepare the extrusion dies between billets, or separate extrusion charges, and represents an appreciable saving in time when it is required to remove and thoroughly clean out a die structure as a part of the usual maintenance of an extrusion press.

Dies constructed in accordance with the descriptions given herein have been successfully employed in the extrusion of aluminum and its alloys. The die structures, however, are not limited to such use and there is no reason to believe that they will not operate with equal success on any metallic or non-metallic materials that respond to die expressing operations.

What is claimed is:

1. An extrusion mechanism comprising a cylinder for confining material to be extruded in combination with a unitary extrusion die structure, said mechanism being mounted for relative reciprocating translation between peripheral sealing relationship of the die structure with the discharge end of the cylinder in a plane normal to the longitudinal axis of the cylinder during an extrusion operation and a parallel plane spaced therefrom on completion of an extrusion operation, said unitary die structure comprising a die block having a front flat surface area normal to the longitudinal axis of the cylinder and conincident with the plane of peripheral sealing relationship of the die structure with the cylinder during an extrusion operation, a die orifice with its axis parallel to the longitudinal axis of the cylinder leading from the front fiat surface area through the die block and having a mandrel in the plane of the front flat surface area of the die block forming an inner surface of the die orifice, a solid abutment rigidly attached to the die block and projecting forwardly away from its front fiat surface area towards and slidably receivable Within the cylinder, said abutment having a flat plane surface substantially parallel to the longitudinal axis of the cylinder intersecting the front flat surface area of the die block and forming a forwardly extending plane stepped surface therewith, said abutment being entirely disposed to one side of the die orifice as Well as substantially entirely disposed to one side of its stepped plane surface and presenting a front flat shearing surface area forwardly spaced from and parallel to the front flat surface area of the die block,

a single web buttress rigidly connected to the stepped plane surface of the abutment and extending outwardly therefrom and rearwardly into rigid connection with the mandrel in the plane of the front flat surface area of the die block, the projected area of the single web buttress, mandrel and front fiat shearing surface area of the abutment constituting substantially the only obstruction in a plane normal to the longitudinal axis of the cylinder to direct axial flow and thrust-contacting abutment of material confined within the cylinder against the front fiat surface area of the die block defined between the intersection of the stepped plane surface of the abutment with the plane of the front flat surface area of the die block and inner wall of the cylinder, the defined front flat surface area of the die block exposed to direct axial flow and thrust-contacting abutment being at least 50 per cent of the cross-sectional area of the cylinder in the plane normal to its axis, and said die orifice being exposed to direct unobstructed axial flow of material under extrusion therethrough over at least 50 per cent uninterrupted length of its entire cross-sectional area, said unitary die structure on completion of an extrusion operation and translation out of sealing relationship with the cylinder carrying with it exteriorly unconfined readily removable unextruded heel material supported in thrust contact with the front flat surface area of the die block over the forwardly extending length of the stepped plane surface of the abutment.

2. The extrusion mechanism of claim 1 in which the mandrel in the plane of the front flat surface area of the die block forms the entire inner surface of a tubular die orifice, the single web buttress rigidly connects the stepped plane surface of the abutment to the mandrel in the front plane surface of the die block, and the buttress constitutes a cantilever support for the mandrel.

3. The extrusion mechanism of claim 1 in which the forwardly projecting abutment is a separate element having a flat rear face parallel to the front flat surface area of the die block, the abutment flat rear face and front fiat surface area of the die block being provided with complementary undercut surfaces for interlocking engagement of the abutment and the die block, and securing means connecting the die block and abutment in unitary interlocked assembly.

References Cited in the file of this patent UNITED STATES PATENTS 1,847,365 Skinner Mar. 1, 1932 FOREIGN PATENTS 1,468 Great Britain Apr. 27, 1874

Images