WO1997048549A1

WO1997048549A1 - Method and die assembly for pressing powders and other fragmented materials

Info

Publication number: WO1997048549A1
Application number: PCT/IL1997/000196
Authority: WO
Inventors: Vladimir Perelman
Original assignee: Gubenko, Lev
Priority date: 1996-06-18
Filing date: 1997-06-16
Publication date: 1997-12-24

Abstract

A method and die assembly (10) for compacting powders or other fragmented materials, by: extruding the selected materials through a first extrusion channel (12) and a second extrusion channel (14) subsequently connected to the first channel at an angle relative to the first extrusion channel, forcing the selected materials to move through the first and second extrusion channels by a plunger press means (16) associated with one of the extrusion channels, where the first and the second extrusion channels being rotatable relatively about axis (5) normal to the plane formed by intersection of said first and second extrusion channels.

Description

METHOD AND DIE ASSEMBLY FOR PRESSING POWDERS AND OTHER FRAGMENTED MATERIALS.

TECHNICAL FIELD

The present invention relates to mechanical processing of fragmented or powder materials, and more particularly concerns method and die assembly for compacting of such materials by use of deformation processing.

The invention are extremely useful in powder metallurgy, processing of hard fragmented wastes, separation of liquid phase from metal cutting wastes such as chips and shavings, or used oil-filter filters, squeezing-out residual oil from oil¬ cake, dewatering composite masses such as cake, radioactive wastes and etc.

BACKGROUND ART There is known an apparatus for compacting the metal powder (see Soviet Union Author Certificate No. 1340901, 1987,) comprising a die assembly formed by : a first pair of fixed plates disposed opposite from each other and a second pair of plates which are slidable disposed opposite from each other and by upper and lower punch press.

The drawback with this arrangement is that it does not permit un-interrupted compacting the materials and produce elongated articles from the powder or fragmented materials.

There is also known an apparatus for deformation processing of metals, ceramics, plastics and other materials comprising a die assembly having a first extrusion channel and a second extrusion channel disposed therein, a punch press assembly associated with the die assembly to force the selected materials to move through the first and second extrusion channels, the first extrusion channel and the second extrusion channel equal cross-sectional areas with the second extrusion channel disposed at an angle relative to the first extrusion channel, the second extrusion channel defined in part by bottom plate assembly which may move relative to the die assembly during extrusion of the selected materials through the die assembly, and the first extrusion channel further comprising a first pair of plates disposed opposite from each other and secured to the die assembly and a second pair of plates which are slidable disposed opposite from each other within the die assembly -- U.S. Patent No. 5400633, (03.09.1993, VI. Segal et al . ) . Such a construction provides uninterrupted processing of fragmented materials and production of elongated articles.

However, this apparatus does not provide compacting of powder metals with low residual porosity (few percents) . In addition, such arrangement fails to provide compacting of coarse metal work filings, etc.

It is known in the art to use pressing processes for metal shavings and chips compacting with simultaneously extruding oil (see US Patent No.5391069, 1995 , Bendzick,

Ervin J.) comprising: subjecting the material to an initial compression under low pressure, forming a loosely compacted pellet and initial separating oil from the material; further high pressure compacting of the material substantially void of interstices.

The drawback with such methods has been their inability to provide squeezing-out residual oil (few of percents) which involves waste of oil and additional processing for its extraction. For purpose removal of residual liquid -- various methods such as evaporate, burning out, vacuuming etc. are frequently employed. Such methods are faulty for many reasons. They are sufficiently expensive since demand complicated and costly equipment and high power consumption and besides frequently involve waste of residual liquids such as oil, useful chemical solutions etc.

SUMMARY OF THE INVENTION The present invention has for its object to remove these drawbacks .

It is therefore, the general object of the invention to provide an un-interrupted compacting of various fragmented and powder materials with extremely low residual porosity and liquid-containing, and to produce elongated articles of such compacted materials.

Thus, provided according to the present invention is an die assembly for compacting metal powder or other fragmented materials comprising a first extrusion channel and a second extrusion channel subsequently connected to the first channel at an angle relative to the first extrusion channel, a plunger press means associated with the die assembly to force the selected materials to move through the first and second extrusion channels. The first and the second extrusion channel may rotate relatively about axis normal to the plane formed by intersection of said first and second extrusion channels.

According to one aspect of the invention one of the extrusion channels is provided with section substantially co¬ axial to the rotation axis. According to second aspect of the invention said first and second channels are provided with section substantially co¬ axial to the rotation axis.

According to the third aspect of the invention there is provided a die assembly for compacting powders and other fragmented materials which are suitable for ceramics and other hardly pressed materials, comprising third extrusion channel subsequently connected to the second extrusion channel made in W - like form, rotatable relatively first and third channels about axis normal to the planes formed by intersection of said channels .

According to the fourth aspect of the invention the intersections of extrusion channels is substantially round in the plane of rotation. According to the fifth aspect of the invention die assembly for compacting powder or other fragmented materials comprising a first extrusion channel and a second extrusion channel subsequently connected to the first channel, a plunger press assembly associated with the die assembly to force the selected materials to move through the first and second extrusion channels, the first and the second extrusion channel may rotate relatively and having cross-section transmitting rotation to the processing material.

According to the sixth aspect of the invention the cross- section of the extrusion channels is polygon.

According to the seventh aspect of the invention the polygon formed by cross-section of the extrusion channel is regular hexagon.

According to the eighths aspect of the invention the cross- section of the extrusion channels is ellipse. And according to the ninth aspect of the invention the cross-sectional area of the first extrusion channel is greater than cross-sectional area of the second extrusion channel and the intersection of said first and second channel is circle being inscribed circle for said first extrusion channel and circumscribing circle for said second extrusion channel.

Thus, further provided according to the present invention is a method of squeezing-out liquids from liquid containing materials comprising the steps of charging a die cavity with the material, subjecting the material to an initial compression under pressure and separation liquid from the material, creating a zone of plastic deformation of the material, passing the material through said zone of plastic deformation within said die so that void interstices and liquid are expelled from the material .

According to the tenth aspect of the invention the die comprising a first extrusion channel and a second extrusion channel subsequently connected to the first channel at an angle relative to the first extrusion channel, the first and the second extrusion channel may rotate relatively about axis normal to the plane formed by intersection of said first and second extrusion channels;

According to the eleventh aspect of the invention the die assembly comprising third extrusion channel subsequently connected to the second extrusion channel having W-shape, rotatable relatively first and third channels about axis normal to the planes formed by intersection of said channels .

According to the twelfth aspect of the invention the die assembly for compacting powder or other discrete materials comprising a first extrusion channel and a second extrusion channel subsequently connected to the first channel, the first and the second extrusion channel may rotate relatively and having cross-section transmitting rotation to the processing material.

And according to another aspect of the invention the cross-sectional area of the first extrusion channel is greater than cross-sectional area of the second extrusion channel and the intersection of said first and second channel is circle being inscribed circle for said first extrusion channel and circumscribing circle for said second extrusion channel.

The method and apparatus of the present invention will be better understood by reference to the following detailed description of the preferred embodiments and attached FIGURES which illustrate and exemplify such embodiments.

It is to be understood, however, that such illustrated embodiments are not intended to restrict the present invention, since many more modifications may be made within the scope of the claims without departing from the spirit of thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic longitudinal section of the die according simplest embodiment of the invention having two inclined extrusion channels;

Fig. 2 shows a longitudinal section of another modification of the apparatus having one of the extrusion channels provided with portion co-axial to the axis of rotation; Fig. 3 illustrates a longitudinal section of modification having both extrusion channels provided with additional portions;

Fig. 4 shows a longitudinal section of the die assembly having rotatable middle extrusion channel and fixed outside extrusion channels;

Fig. 5 shows a section of die assembly having co-axial extrusion channels with equal cross-section areas; and

Fig. 6 shows a section of die assembly having co-axial extrusion channels with different cross-section areas.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As schematically shown in Fig. 1, the die assembly, generally denoted 10, is characterized by comprising first extrusion channel 12 and second extrusion channel 14 connected to the first extrusion channel 12. The channels 12 and 14 are rotatable around the axis S normal to the plane of the channels intersection. The angles cq and α₂ between the channels 12 and 14 and rotation axis S may be of 5 to 45° (up to 90° between the channels) .

It is readily understood that if the channels 12 and 14 have equal, circle-shape cross-section areas, the intersection (along line A) of the channels 12 and 14 are ellipse-shape in initial phase. Under rotation along axis S the intersection area changes due the channels relative rotation, and it causes coarse, exploded surface of the outputted compact rod. Therefore, in order to improve the surface of produced rod, the cross-section of the extrusion channels 12 and 14 may be made in ellipse or another form, forming a circle in the plane of channels intersection. The material is first charged into first extrusion channel 12 from storage capacity (not shown) by any well known in the art means which need not be further described. The material are then forced by plunger 16 and move through the first 12 and second 14 extrusion channels. In the same time the channels 12 and 14 rotate relatively about axis S normal to the plane of their intersection. Rotated channel (either first or second) operates as a "spanner" providing rotation of the material and thus, cause shear deformation in the plane of channels rotation. Combination of compressive load and shear deformation provides compacting with extremely low residual porosity under relatively low pressure and load. Additional shear deformation in the channels intersection zone are provided due to effect of Equal-channel-angular extrusion and depends on angle between the extrusion channels. The second extrusion channel provides a "reaction force" in response to pressing the material due friction of its walls or constriction portion or plunger therewithin, thus providing pressing of the charged material together with the plunger 16. The summary shear deformation can be readily adjust by the relative rotational velocity,

"reaction force" of the second channel and angle between the channels .

It will be thus appreciated that the powder or other fragmented material is periodically discharged into the die assembly and the material continuously fed through the channels 12 and 14, forming elongated rod of compacted material.

As better seen in Fig. 2 one of the extrusion channels 22 or 24, preferably rotatable one, can be provided with the section 26 substantially parallel to the rotation axis. Such an arrangement is more convenient in sense of un-interrupted outlet of compacted material formed as elongated rod and transmission of rotation to the rotating channel.

For reason given in discussing Fig. 2, in this Fig. 3 embodiment both extrusion channels 32 and 34 provided with sections 36 and 38 substantially parallel to the rotation axis. Such an arrangement is most useful for compacting of hardly- pressed materials and mixtures.

Fig. 4 shows another alternative embodiment of the die assembly, generally denoted 40 comprising fixed first 42 and third 44 extrusion channels having sections 46 and 48 substantially co-axial to the rotation axis. Second extrusion channel 50, having V-shape and connected to the first 42 and third 44 extrusion channels is rotatable relatively first and third channels about axis normal to the planes formed by intersection of said channels. Plunger 52 accommodates within first 42 or third 44 extrusion channels provide compression and moving the material through the die 40 press assembly.

Composition of few bends of the die 40 and rotation movement creates alternating deformation of the material in the channels intersection zones and, thus provides effective compacting of ceramics, ceramic compositions and etc.

It is thus evident that all these embodiments, shown in Figs. 2-4 function in a similar manner as the fig. 1 embodiment . Fig. 5 shows yet another embodiment of the die assembly, generally denoted 50 comprising a first extrusion channel 52 and a second extrusion channel 54 subsequently connected to the first channel. To force the material to move through the extrusion channels 52 and 54 there are provided a plunger press assembly 56. The channels 52 and 54 are co-axial and rotatable relatively. Shape of cross-section of the extrusion channels 52 and 54 must provide transmission of rotation to the material, therefore it can be a polygon, preferably regular hexagon or ellipse . Fig. 6 illustrates another alternative embodiment of die assembly 60 wherein cross-sectional area of the first extrusion channel 62 is greater than cross-sectional area of the second extrusion channel 64. The intersection of said first 62 and second 64 channel is circle. It is evident that for smooth connection of the channels 62 and 64, the intersection circle is inscribed circle for the first wider extrusion channel 62 and circumscribing circle for the second narrower extrusion channel 64.

Again, these Figs. 5 and 6 function in a similar manner as the Fig. 1 embodiment.

In order to compact separate articles formed, for example, as a cylinder with regular butt-ends the die assembly may be provided with an additional plunger within second or third extrusion channel. In this case The compressive load of contrary direction may provided which is more useful for hardly-compacted materials, such as ceramics, etc.

It is thus evident that by providing most simple and straightforward structural features a die assembly for compacting powders and fragmented materials of a high efficiency is achieved. In comparison with traditional compacting apparatus, these die assemblies has a number of significant technological advantages. The most important is that large, strictly located and uniform deformation can be developed under relatively low pressure and load during un- interrupted compacting of the material. The material continuously "passed" through the located deformation zone and this leads to remarkable changes in structure and physical- mechanical properties of various powder and fragmented materials. Practically pore-free elongated articles can be produced by means of the present invention.

It is possible by utilizing the deformation processing of liquid containing fragmented or other materials to squeeze-out the liquids from the materials without residual.

The essential of the present invention lies in passing the material through zone of plastic deformation so that void interstices and liquid are expelled from the material.

The process of the invention is preferably implemented in a die assembly of any known design, providing preliminary loosely compacting of the material and further creating zone or plane of plastic deformation thereof.

There are known in the art such a die assemblies having tapered passage, additional plungers or punch press assemblies and etc.

The material are charged into a die cavity and subjected to an initial, loosely compression under pressure (using plungers or punches) . The liquid partly are squeezed-out from material and expelled from the die assembly through gap between the plunger and die walls. By applying, for example a shear deformation there are created within the material a zone or plane of plastic deformation of the material. Under the pressure of the plunger the material are passed through the zone of plastic deformation within the die assembly so that void interstices and liquid are expelled from the material . The die assemblies of Fig. 1 design as one example is preferable for obtaining a plane of torsion deformation used in the present invention.

The squeezed-out liquid may be expelled through the gap in the channels connection, which can be arranged due the viscosity of the separated liquid.

It will be appreciated that the powder or other discrete material is periodically discharged into the die assembly and the material continuously fed through the channels 12 and 14, forming elongated dewatering rod of compacted material .

Figs. 2 - 6 show another alternative embodiments of the die assembly. It is evident that these embodiments function in a similar manner as Fig. 1 embodiment.

It is thus evident that by providing most simple mechanical processing of a high efficiency of squeezing-out liquids from fragmented and other materials is achieved. In comparison with traditional dewatering methods this invention has a number of significant technological advantages. The most important is that under relatively low pressure due to large, strictly located deformation practically full separation of the liquid phase can be reached during un-interrupted compacting of the material. The material continuously passed through the located deformation zone or plane and this leads to remarkable changes in structure and physical-mechanical properties of various powder and discrete materials. Practically pore- free, without interstices elongated articles can be produced by means of the present invention.

Those skilled in the art will readily appreciated that numerous changes, variations and modifications may be applied to the invention as heretofore exemplified without departing from the scope of the invention as defined in and by the appended claims.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A die assembly for compacting powder or other fragmented materials comprising: a first extrusion channel and a second extrusion channel subsequently connected to the first channel at an angle relative to the first extrusion channel; a plunger press means associated with one of the extrusion channels to force the selected materials to move through the first and second extrusion channels, characterized by the first and the second extrusion channel being rotatable relatively about axis normal to the plane formed by intersection of said first and second extrusion channels.

2. The die assembly of Claim 1 wherein one of said extrusion channels is provided with section substantially co¬ axial to the rotation axis.

3. The die assembly of Claim 1 wherein said first and second channels are provided with section substantially co¬ axial to the rotation axis.

4. The die assembly of Claims 1-3 further comprising third extrusion channel subsequently connected to the second extrusion channel, being made in W - like form and rotatable relatively to the first and third channels about axis normal to the planes formed by intersection of said channels.

5. The die assembly of Claims 1-4 wherein said intersections of extrusion channels is substantially round in the plane of rotation.

6. Die assembly for compacting powders or other fragmented materials comprising: a first extrusion channel and a second extrusion channel subsequently connected to the first channel; a plunger press assembly associated with the die assembly to force the selected materials to move through the first and second extrusion channels, characterized by the first and the second extrusion channel being rotatable relatively and having cross-section transmitting rotation to the processing material.

7. The die assembly of Claim 6 wherein the cross-section of the extrusion channels is polygon.

8. The die assembly of Claim 7 wherein the polygon is regular hexagon.

9. The die assembly of Claim 6 wherein the cross-section of the extrusion channels is ellipse.

10. The die assembly of one of the Claims 6-8 wherein cross-sectional area of the first extrusion channel is greater than cross-sectional area of the second extrusion channel and the intersection of said first and second channel is circle being inscribed circle for said first extrusion channel and circumscribing circle for said second extrusion channel.

11. A method of squeezing-out liquids from liquid containing materials comprising the steps of: charging a die cavity with the material; subjecting the material to an initial compression under pressure and separation liquid from the material; creating a zone of plastic deformation of the material under said pressure, characterized by passing the material through said zone of plastic deformation within said die so that void interstices and liquid are expelled from the material .

12. The method of Claim 11 wherein said zone of plastic deformation being created by torsion deformation.

13. The method of Claim 12 wherein said torsion deformation being created by relative rotatition of the die elements .

14. The method of Claim 13 wherein said die comprising a first extrusion channel and a second extrusion channel subsequently connected to the first channel at an angle relative to the first extrusion channel; the first and the second extrusion channel may rotate relatively about axis normal to the plane formed by intersection of said first and second extrusion channels;

15. The method of Claim 14 wherein said die further comprising third extrusion channel subsequently connected to the second extrusion channel having W-shape, rotatable relatively first and third channels about axis normal to the planes formed by intersection of said channels.

16. The method of Claims 13 wherein said die comprising: a first extrusion channel and a second extrusion channel subsequently connected to the first channel; the first and the second extrusion channel may rotate relatively and having cross-section transmitting rotation to the processing material.

17. The method of Claim 16 wherein cross-sectional area of the first extrusion channel is greater than cross- sectional area of the second extrusion channel;and the intersection of said first and second channel is circle being inscribed circle for said first extrusion channel and circumscribing circle for said second extrusion channel.

18. The method of any of Claims 14-16 wherein a gap between said first and second extrusion channels arranged for expelling out the squeezed-out liquid.