Note: Descriptions are shown in the official language in which they were submitted.
CA 02766281 2012-01-26
Description:
The invention is a 2 sleeve metal filling system, with the injection plunger
in the
retracted position, for a cold chamber die casting machine which has the die
clamping mechanism and injection system inclined at an angle sufficient to
hold
the molten required to produce the required casting in the injection sleeve
with
the die halves and platens in the open position.
The two sleeve metal filling and injection system comprises of a filling
sleeve (1)
with a filling port (1A) and a filling plunger (2), activated by the filling
cylinder
(3) which will be horizontal, or at a slightly declining angle, to allow metal
to
partially flow into the injection sleeve by gravity, and an injection sleeve
(4) and
an injection plunger (5), activated by the injection cylinder (6) which are at
an
inclined plane.
When metal is required, either at the start of the initial cycle, or during
the the
normal production cycle, with the injection and filling plungers in the
retracted
position, the metered amount of metal will be poured into the filling sleeve
port
(1A) by means of a mechanical or hand operated ladle.
The filling plunger will then be activated to move forward at a controlled
speed
to the end position. This end position will be measured so that at the end of
the
stroke of the filling cylinder, the filling plunger will not be in the path of
the
injection plunger, but at the same time will leave a minimum of metal
remaining
at the end of the filling sleeve.
When the filling plunger has reached the end position, all of the metal would
have been pushed into the injection sleeve to fill the sleeve to level (D).
The
injection plunger will be pushed by the injection cylinder so that it will
proceed
at a controlled speed to a set position. This position will be established as
the
most forward position which will not cause metal to pour out from the open end
of the injection sleeve (E). The injection plunger will be stopped and held in
this
position until the die is fully closed, and vacuum, if used has been
activated, and
the signals for the shot to proceed has been activated. When the shot is
activated,
with the machine closed and safely locked, the plunger will be advanced at the
programmed speed and pressures, and this pressure will be applied until the
machine starts to open and the die halves part and the gates and runners and
the
part known as the biscuit is ejected from the injection sleeve.
The filling plunger and the injection plunger will immediately retract to the
home position and be refilled to start a new cycle and advance to the shot
ready
position, ready for the die to go through the extract, die cool and die spray
and
close process. The shot will be ready to advance as soon as the die closes and
will
save considerable cycle time.
CA 02766281 2012-01-26
Research
The following patents have been researched:
1) Patent CA 2083082:
This patent describes an injection unit for a cold chamber. The injection unit
is
inclined at an angle of 45 degrees, and is a top fill system which can be
filled with
the machine in the open position. The platens of this machine opens
horizontally, which means that each die which is made for this machine will
not
be interchangeable with dies made for the conventional horizontal machine with
a horizontal injection system.
2) Toshiba Machine : the new LEOMACS system:
This system comprises of a vertical injection, with an electromagnetic pump
which pumps a measured amount of metal into the injection sleeve with the
injection plunger in the retracted position.
3) U.S. Patent 4006774:
This patent describes a vertical injection system on a machine with the
platens
opening vertically and claims that there will be no contact of metal with the
injection sleeve, as metal will be pourec into a cup shape face of the
vertical
plunger.
4) U.S. Patent 3208113:
This patent describes an inclined injection sleeve with a metal filling port
in the
position in front of the retracted piston. The injection sleeve enters the
stationary platen and stationary die at an inclined angle, and the machine
platens are on a horizontal plane, which could cause a conflict as the machine
platens open.
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A review of current popular and commonly used cold chamber Casting machine
injection
systems and their advantages and disadvantages.
SKETCH 1 (Fig.2)
Horizontal Cold Chamber Machine.
The majority of Cold Chamber Die Cast machines in use and in the market today
are
of the horizontal design where the machine and clamp system is designed and
built in
the horizontal plane with the injection on the horizontal plane. This has been
the
accepted design form ever since cold chamber machines were manufactured.
The advantages of this design are as follows.
a) This is currently the most common Cold Chamber system used, and as a result
there is familiarity with it, and a comfort zone. Most Die casting companies
are
competing at the same level, and will not be concerned until a better system
comes along.
b) Installation of dies on the horizontal plane is fairly easy to accommodate,
and the
installation of ancillary equipment is easy to accommodate, and is available,
again
due to the fact that there is familiarity.
The disadvantages of this design are as follows.
a) The fact that the metal is poured in a horizontal sleeve, and there is a
large
volume of air and gases in the sleeve which become entrapped in the metal when
injection takes place, causing porosity in the casting, and rejects and poor
quality
of product. Molten aluminium also has a high surface tension quality, and as a
result, it is more difficult to expel any entrapped air or gases. This will
result in
requiring more pressure at faster fill times and higher speeds to compress any
entrapped gases to reduce porosity. This higher pressure at higher speeds will
result in more turbulent flow of metal and will cause die wear and machine
wear
and ultimately higher costs and less efficiency.
b) The high surface area of molten metal contact to the colder shot sleeve
causes the
metal to chill, and as a result, the metal being injected has a high
percentage of
sludge and solids, and is not in the molten state which we often assume. The
result again is that higher pressures are required to inject this material and
this
causes additional wear and tear.
c) The injection sleeve on this conventional type of machine is in the
horizontal
position, and as a result, molten metal can be poured into the sleeve only
after the
machine is fully closed and locked, resulting in loss of significant
production
time.
d) If a Vacuum system is used, then the shot plunger will have to be advanced
past
the filling port and stopped for the vacuum to be applied and to be effective
causing a loss of production time and efficiency.
SKETCH 2 (Fig.2)
Uni-Cast 45 Degree Injection Design (Canadian Patent CA 2083082. US Patent
5787962). This machine is a horizontal die casting machine, and the injection
system
CA 02766281 2012-01-26
comes in from the lower part of the front platen at an angle inclined at 45
degrees.
This patent covers the idea that the injection of the metal is at a softer
angle of 45
degrees rather than the more drastic direction change of 90 degrees, and the
pouring
of the metal into the sleeve is from the open, top end of the sleeve when the
die faces
and machine platens are in the open position.
The advantages of this design are as follows.
a) The inclined angle of the shot sleeve at 45 degrees is an advantage since
this
will assure that most of the gases in the shot sleeve will be pushed out
through
the sleeve, and through the gates and runners ahead of the molten metal and be
vented from the die with minimal inclusion into the casting, resulting in less
porosity and gas entrapment.
b) If Vacuum is used on the die, then vacuum can be applied as soon as the die
surfaces are closed and the machine is fully locked, thus saving time as
compared to the horizontal type of machine.
c) The shot sleeve can only be filled with the machine in the open position.
This
can be an advantage of reducing cycle time as compared to the conventional
horizontal die casting machine, which requires that the die faces are closed
and
locked before metal can be filled into the shot sleeve.
The disadvantages of this design are as follows.
a) The design of the shot sleeve entering the front stationary die at 45
degrees will
be a disadvantage as this will mean that any die which is made for this
machine
will only fit in this type of machine, and will not be able to be
interchangeable
with any other conventional machine without major modifications, and
significant costs. There are no machines commercially available with this
design
at this time.
b) The injection sleeve at 45 degrees from the die opening stroke could cause
interference on the opening stroke if there is excess metal in the sleeve.
c) Dies made for the any machine with the injection sleeve at 90 degrees from
the
parting line, as most dies are currently made, will not fit on a machine with
the
injection system at 45 degrees from the parting line, and as a result, it will
be
difficult for industry to accept this type of injection system.
d) The cost to make tooling to be able to use this system will be
significantly
higher than for conventional systems.
e) The filling can only be done with the machine in the open position would
mean
that there will be another piece of machinery for ladling the metal,
interfering
with the die open area along with a parts extractor, and die sprayer which all
will have to come between the die faces on each cycle. This will make it more
difficult for die setups and maintenance, and also could possibly extend cycle
times.
SKETCH 3 (Fig.2)
Horizontal Platen, Vertical Injection Die Casting Machine:
Hand or Mechanized Ladle (A), or Electromagnetically pumped into sleeve
(B).
This design of machine is one in which the clamping mechanism is on the
horizontal
plane, and the Injection system is vertical at the Parting line from the
underside of the
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die. The molten metal is either poured manually or by means of a mechanical
ladle
into the top of the shot sleeve, or by means of an electromagnetic pump.
The advantages of this design are as follows.
a) Positive displacement of air and gases when the metal is injected into the
die,
resulting in less porosity in the product
The disadvantages of this design are as follows.
a) Dies made for these designs of machines will not fit conventional
horizontal
machines.
b) For the top fill ladle system, the fact that the filling can only be done
with the
machine in the open position would mean that there will be another piece of
machinery for ladling the metal, with the furnace for the metal interfering
with the
die open area along with a parts extractor, and die sprayer which all will
have to
come between the die faces on each cycle. This will make it more difficult for
die
setups and maintenance.
SKETCH 4 (Fig.2)
Vertical Platen, Vertical injection using siphon metal filling system. (A) or
ladled
with the machin platens in the open position.
The design of this machine is one in which the platen assembly is in the
vertical position,
and the injection system is also vertical.
Metal is siphoned directly from the furnace into the shot sleeve, due to
vacuum being
applied to the die cavity. Metal can also be top filled into the sleeve with a
manual or
mechanized ladle with the machine platens and die in the open position.
The advantages of this design are as follows.
a) Positive displacement of air and gases when the metal is injected into the
die,
resulting in less porosity in the product
b) The configuration of this design makes it ideal for products which require
inserts to
be loaded into the die to be cast into the product.
The disadvantages of this design are as follows.
a) One of the issues with this design was the inconsistency of the amount of
metal
charged into the die when the siphon system was used.
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Drawing Detail Information. DWG. FIG 1
A Angle of Incline required for the process.
B Die Cast Machine Clamping assembly.
C Location of where the feeder sleeve is attached to the injection
sleeve.
D Metal Level when metal is injected into injection sleeve.
E Metal level when injection plunger is advanced to safe position,
with machine open or closed.
Fig 1 Representative drawing showing 3 views of assembly
Fig. 2 Existing Casting system sketches
1 Filler Sleeve
1A Filler Sleeve Port
2 Filler Plunger
3 Filler Cylinder
4 Injection Sleeve
Injection Plunger
6 Injection Cylinder
7 Front Stationary Platen
8 Front Stationary Die
9 Rear Moving Platen
Rear Moving Die
11 Rear stationary Platen
12 Tie Bars
13 Mounting Bracket for Metal Filler System
14 Machine frame
