GB2138731A

GB2138731A - A Method and Apparatus for Forming an Extruded Product from Powdered or Granular Material or from Feed-Stock

Info

Publication number: GB2138731A
Application number: GB08311347A
Authority: GB
Inventors: Ian Thomas
Original assignee: Penny & Giles Conductive Plast
Current assignee: Penny & Giles Conductive Plast
Priority date: 1983-04-26
Filing date: 1983-04-26
Publication date: 1984-10-31
Also published as: GB8311347D0; GB2138731B

Abstract

Powdered or granular material 11 or rod or wire feed-stock 25 is fed into the open end of a chamber 12 formed in a rotatable platen 13 and is compacted within the chamber 12 by a compacting tool 15 rotatable about an axis 16 which is inclined to the axis 14 about which the platen 13 rotates and which intersects the axis 14, the compacted material 11 within the chamber 12 being extruded through a die assembly 17 to form the extruded product. <IMAGE>

Description

SPECIFICATION A Method and Apparatus for Forming an Extruded Product from Powdered or Granular Material or from Feed-Stock This invention relates to a method of forming an extruded product from a powdered or granular material or from feed-stock and apparatus for carrying out the method.

European patent no. 0014570 discloses a rotary forging machine having first and second platens disposed in a machine frame, means being provided for rotating both platens about independent axes relative to the machine frame, means for adjusting the angle between the platens whilst the platens are rotating and means for applying a force to at least one platen to move it towards the other platen, the axes of the platens always being disposed at an angle to each other and the axes intersect in the plastically deformable region of the workpiece so that when the angle is adjusted the point of intersection always remains in the plastically deformable region of the workpiece.

We have found that the principle of this forging machine can be utilized for forming a product from a powdered or granular material or from feed-stock by an extrusion process.

According to the present invention there is provided a method of forming an extruded product, comprising the steps of feeding a powdered or granular material or a wire or rod feed-stock into a chamber formed in a rotating platen having an outlet die and applying compression to the fed material whilst in said chamber in a localized region which moves through the material by means of a compacting tool rotating relative to the platen about an axis disposed at an angle to the axis of rotation of the platen and which intersects said axis to cause the compacted material in the region of the die to flow through said die.

The method can be used for the production of extruded sections of metal, plastics or similar materials whose starting material is in powdered, granular or other particulate form or in lengths or rod or wire.

The process provides a means of compacting the starting material in a continuous manner and allows for compaction to such an extent that the material becomes welded together either by cold pressure welding or high temperature welding due to thermal energy generated during compaction or externally derived thermal energy, and the welded material is then extruded through the die to be in the desired cross-section.

According to the present invention in another aspect there is provided apparatus for use in forming an extruded product, comprising a platen rotatable about an axis, a chamber formed in said platen and having an upper end, an outlet die communicating with the bottom end of the chamber, a compacting tool disposed at the open end of the chamber, means for rotating the tool about an axis disposed at an angle to the axis of rotation of the platen, said axis about which the tool is rotated intersecting the axis about which the platen is rotated, and means for supplying a feeding or powdered or granular material or wire or rod feed-stock into the open end of the chamber.

An embodiment of the present invention will now be described, by way of an example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through part of an apparatus for carrying out the method according to the present invention, Figure 2 is a transverse section showing the compacting zone, and Figure 3 is a section similar to that of Figure 1 showing a feed-stock wire or rod.

The apparatus shown in Figure 1 comprises a hopper 10 through which granular or powdered material 11 is fed into a chamber 12 formed in a rotatable platen 1 3 rotating about an axis 14. The material 11 moves thgough the hopper 10 by gravity and the hopper 10 may be vibrated.

Located above the chamber 1 2 is a compacting tool 1 5 which is rotated about an axis 1 6 which is at an angle a to the axis 14. The axis 1 6 intersects the axis 14. The hopper 10 guides the material 11 into the open side of the compaction head formed by the platen 13 and tool 15. At the bottom of the chamber 12 there is provided a die assembly 1 7 comprising an initial die segment 1 8 having a conical entry portion 19 and a die segment 20 which defines the cross-section of the extrusion. Alternatively the die segment 20 may comprise a plurality of elements to produce complex sections.

The material 11 is fed into the chamber 1 2 and the relative motion of the platen 13 and tool 1 5 is such as to compact the material in the chamber 12. The compacting zone is shown at 21 in Figure 2 and this zone moves through the material. The relative motion of the platen 13 and tool 1 5 compacts the material in zone 22 indicated in Figure 1. With the addition of further material in a continuous manner each revelation will give an increase in the density of the material in the zone 22 until further densification can no longer take place.At this point the compressive stress in the region of the die assembly 1 7 will cause the compacted material to flow out of the compaction zone 22 into the die assembly 1 7. The conical shape of the entry 1 9 into the die segment 1 8 causes further densification of the extruded material.

It will be appreciated that within the compaction zone 22 the particles of material become welded together by cold pressure welding. Alternatively, in order to produce high temperature welding, the platen 13 is heated by a heating coil 23. The heating can be carried out by any other suitable heating means.

In the modified arrangement shown in Figure 3 the hopper 10 is replaced by a guide 24 for guiding a wire or rod feed-stock 25 into the chamber 12. The feed-stock 25 can be fed from a roll or coil or from other suitable feeding apparatus. The apparatus is able to re-commence extrusion after stopping without having to join a fresh feed-stock 25 to the end of a consumed length of feed-stock, since the compaction in the zone 22 will be sufficient to re-commence extrusion.

It will be appreciated that with this method and apparatus it is possible to produce extrusions of infinite length.

Claims

1. A method of forming an extruded product, comprising the steps of feeding a powdered or granular material or a wire or rod feed-stock into a chamber formed in a rotating platen having an outlet die and applying compression to the fed material whilst in said chamber in a localized region which moves through the material by means of a compacting tool rotating relative to the platen about an axis disposed at an angle to the axis of rotation of the platen and which intersects said axis to cause the compacted material in the region of the die to flow through said die.

2. A method as claimed in claim 1, in which powdered or granular material is continuously fed by gravity through an inclined hopper into the open upper end of the chamber.

3. A method as claimed in claim 2, in which the hopper is vibrated.

4. A method as claimed in claim 1, in which wire or rod feed-stock is continuously fed into the open upper end of the chamber by a guide member.

5. A method as claimed in any preceding claim, in which the material is heated whilst in the chamber by an external heating means.

6. A method of forming an extruded product, substantially as hereinbefore described with reference to the accompanying drawings.

7. Apparatus for use in carrying out the method claimed in claim 1, comprising a platen rotatable about an axis, a chamber formed in said platen and having an upper end, an outlet die communicating with the bottom end of the chamber, a compacting tool disposed at the open end of the chamber, means for rotating the tool about an axis disposed at an angle to the axis of rotation of the platen, said axis about which the tool is rotated intersecting the axis about which the platen is rotated, and means for supplying a feeding or powdered or granular material or wire or rod feed-stock into the open end of the chamber.

8. Apparatus as claimed in claim 7, including means for heating the platen.

9. Apparatus as claimed in claim 8, in which the heating means comprises a heating coil surrounding the platen.

10. Apparatus for use in forming an extruded product, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.