Forming an extruded bar out of metal chips

Apparatus for extruding metal chips or filings into a bar stock. The extruding machine uses graphite lubrication, and an oversized wooden (or other compressible material) plug for the initial compaction. The face of the ram contains undulations therein so the ends of adjacent charges will be better held together.

BACKGROUND OF THE INVENTION 
In various machining operations, an abundance of metal chips and filings 
are generated which used to be discarded as waste. Presently, these metal 
particles are formed into briquettes, and shipped back to the foundry or 
steel mill where they are remelted, so that they can ultimately become a 
usable product. In these days of energy shortages, the energy necessary to 
melt these briquetted chips and/or filings prior to reshaping or reforming 
them, is costly and also fuel and energy consuming. It would be desirable 
if the metal chips and filings could be worked into a final form without 
the necessity of remelting. 
SUMMARY OF THE INVENTION 
In accordance with the invention apparatus is provided for extruding metal 
chips or filings into a bar stock. The extruding machine uses graphite 
lubrication, and an oversized wooden plug to accomplish the initial 
compaction of the metal particles. The face of the ram contains 
undulations therein so the ends of adjacent charges of metal particles 
will be better held together. Thus, these metal particles can be reformed 
into a final product without the necessity of remelting, which would 
require consumption of costly and scarce fuels.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Looking now to the drawings, numeral 10 indicates the extruding machine in 
its entirety. A hopper or bin 12 contains the metal particles 14 (chips or 
filings) which are to be extruded into a bar stock. A ram 16 is 
reciprocable in the lower portion of the bin by means of hydraulic forces 
through inlets 20 or 22, which can be applied to either side of the piston 
18, which is attached to the ram 16. The end face 24 of the ram 16, which 
comes into contact with the metal particles, has a centrally located 
protuberance 26 surrounded by an annular indention 28, which flares back 
out near its outer periphery. The reason for these undulations or 
particular shape or configuration will be explained in more detail later. 
The extruding die 30 has an inlet end 32 having a large diameter, and an 
outlet end 34 having a somewhat smaller diameter. The ratio of these 
diameters may be for example, 2:1. In order to reduce the wear on the die 
30 caused by friction, graphic 36 or other lubricants compactible within 
material being extruded, is introduced around the periphery of the die at 
its inlet end 32 by a means of a series of openings directed thereto. 
These lubricants also prevent the material being extruded from welding to 
the die surfaces 30 because of the high friction occurring during 
extrusion. 
A wooden (or other compressible material) plug 38 is initially placed in 
the extruding machine, for causing the initial compaction of the metal 
particles 14. This plug 38 is small enough so that it will enter the inlet 
end 32 of the extruding die, but is larger than the outlet end 34, so that 
it will have to be compressed before it can pass through the extruding 
die. Once the machine has been put into operation, and the particles have 
been compacted sufficiently to force the wooden plug 38 through the 
reducing die 30, the resistance of the metal particles themselves to 
compaction as they pass through the reducing diameter portion of the 
extruding die, creates the back pressure necessary for causing compaction 
of the metal particles into a single bar stock. 
The FIG. 2 embodiment is the same as FIG. 1 with one exception. In FIG. 2, 
the guide tube 40 is made removable. It can be used for securing a thin 
walled tube 42 in the outlet of the extruding machine. Thus, a rod of 
dense extruded material, captured in the tube 42, can be formed. When the 
tube is completely full, the guide tube 42 can be removed, allowing 
removal of the tube 42 filled with compacted material. This filled tube 
can be heated for subsequent forging or extrusion processing without 
oxidation. The tube would reduce during such process so that a case of 
thin metal would enclose the core composed of consolidated granular 
material. A material with such a case would have similar external 
properties to solid bar stock, such as smooth surface, regular appearance 
and oxidation resistance. 
The operation of the machine should be obvious. When initially starting, a 
wooden plug 38 is placed at the inlet end 32 of the extruding die. This 
provides the initial compaction, and also provides for a flat end on the 
bar stock. Metal chips 14 entirely fill the bin, while the ram 16 is in 
its withdrawn position, being located entirely out of the bin. To start 
the operation, the ram is moved through the bin, forcing a charge of metal 
chips or filings into the inlet end 32 of the extruding die. Depending on 
the compactability of the metal chips or filings, and the resistance set 
up by the wooden plug 38 initially, one or more reciprocations of the ram 
will be necessary to initially move the wooden plug 38 entirely through 
the extruding die 30. As the ram 16 is reciprocated back out of the bin 
again, to allow another charge of metal particles to fill the lower 
portion thereof, and then move back into and through the bin again, the 
matching end faces of the charges wil be interlaced or interlocked because 
of the undulations 24 on the surface of the ram end. As these interlaced 
portions pass through the reducing diameter portion of the extruding die, 
they are squeezed tightly together, forming one continuous string or chain 
of extruded metal bar stock. The graphite 36 introduced around the 
periphery of the inlet end 32 of the extruding die prevents excessive 
wear, which would occur without it. This would cause a lot of downtime, 
necessary to replace the extruding die 30, making the operation more 
costly. 
From the above, it can be seen that the apparatus of the invention allows 
metal chips or filings to be extruded into a continuous bar stock in an 
efficient and reasonably priced manner, without the necessity of 
remelting, which would require large amounts of energy. The finished bar 
stock from use of the present invention would not have the strength of bar 
stock made by melting the metal particles and thereafter casting, but 
there should be sufficient strength in the extruded bar stock for any 
number of uses; i.e., aluminum windows could be made in this manner.