Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
PCT/CA2008/001619
CA 02699237 2010-03-11 17 April 2009 17-04-2009
H-7130-0-WO
METAL-MOLDING CONDUIT ASSEMBLY OF METAL-MOLDING SYSTEM
TECHNICAL FIELD
The present invention generally relates to, but is not limited to, molding
systems, and more
specifically the present invention relates to, but is not limited to a metal-
molding conduit
assembly of either a metal-molding system or a metal injection-molding system.
BACKGROUND OF THE INVENTION
Examples of known molding systems are (amongst others): (i) the HyPET
(trademark) Molding
System, (ii) the Quadloc (trademark) Molding System, (iii) the Hylectric
(trademark) Molding
System, and (iv) the HyMET (trademark) Molding System, all manufactured by
Husky
Injection Molding Systems (Location: Canada; Web Site: www.husky.ca).
United States Patent Number 5,040,589 (Inventor: BRADLEY et al.; Published:
1991-08-20)
discloses the following (from line 4 to 24 of column 6): "The barrel is
preferably bimetallic
having an outer shell of alloy 1-718, which is a high nickel alloy and
provides strength and
fatigue resistance at operating temperatures in excess of 600 C. Since the
alloy 1-718 will
corrode rapidly in the presence of magnesium at the temperatures under
consideration, a liner of
a high cobalt material, such as Stellite 12 (Stoody-Doloro-Stellite
Corporation) is shrunk fit
onto the inner surface of the barrel. Any appropriate bimetallic barrel having
chemical and
thermal resistance, sufficient strength to withstand shot pressures, and
resistance to wear may
be used. A typical magnesium alloy that can be used in practice is AZ91B,
containing 90% Mg,
9% Al, and 1% Zn. This alloy has a solidus temperature of 465 C., a liquidus
temperature of
596 C., and a desirable slush morphology temperature of approximately 580 -
590 C.,
preferably 585 C. Thus, the apparatus of the subject concept must operate at
temperatures
which are much higher than those encountered in thermoplastic injection
molding." It appears
that 5,040,589 discloses a barrel (which is an example of a conduit) that uses
a combination of
Inconel (trademark) 718 in an outer shell of the conduit, and Stellite
(trademark) 12 in an inner
shell of the conduit.
United States Patent Number 5,983,975 (Inventor: NILSSON; Published: 1999-11-
16) discloses
the following (from line 59 of column 3 to line 12 of column 4): "Since the
nickel content of
the alloy 718 is subject to be corroded by molten magnesium, currently the
most commonly
used thixotropic material, barrels have been lined with a sleeve or liner of a
magnesium
1
AMENDED SHEET
PCT/CA2008/001619
CA 02699237 2010-03-11 17 April 2009 17-04-2009
H-7130-0-WO
resistant material to prevent the magnesium from attacking the alloy 718.
Several such
materials are Stellite 12 (nominally 30Cr, 8.3W and 1.4C; Stoody-Doloro-
Stellite Corp.), PM
0.80 alloy (nominally 0.8C, 27.81 Cr, 4.11 W and bal. Co. with 0.66N) and Nb-
based alloys
(such as Nb-30Ti-20W). Obviously, the coefficients of expansion of the barrel
and the liner
must be compatible to one another for proper working of the machine. Because
of the
significant cycling of thermal gradient in the barrel, the barrel experiences
thermal fatigue and
shock. This was found to cause cracking in the barrel and in the barrel liner.
Once the barrel
liner has become cracked, magnesium can penetrate the liner and attack the
barrel. Both the
cracking of the barrel and the attacking of the barrel by magnesium were found
to have
contributed to the premature failure of the above mentioned barrels." It
appears that 5,983,975
discloses a barrel (an example of a conduit), which uses the combination of
Inconel 718 (in the
outer shell) and Stellite 12 (in the inner shell).
United States Patent Number 6,520,762 (Inventor: KESTLE et al.; Published:
2003-02-18)
discloses the following (from line 66 of column 11 to line 5 of column 12):
"In an application
of the machine where the melt of material is a metal in a thixotropic state,
for example,
magnesium, the nozzle may be made from DIN 2888 or DIN 2999. The accumulator,
first
barrel coupler (including the axial force isolator), and the second portion
may all be made from
INCONEL 718 (a nickel alloy) with a STELLITE 12 (wear-resistant cast non-
ferrous alloy)
liner. In an application of the machine where the melt of material is plastic,
the nozzle may be
made from SAE 4140 steel with an H13 tip. The accumulator and first barrel
coupler (including
the axial force isolator) may be made from 4140 with a cast liner. The second
portion may be
made from 4140 with a cast liner." It appears that 6,520,762 discloses a
barrel (an example of a
conduit), which uses the combination of Inconel 718 (in the outer shell) and
Stellite 12 (in the
inner shell).
Stellite 12 is manufactured by Deloro Stellite (Telephone: 1-800-267-2886; Web
site: www.
http://www.stellitesolutions.com). Inconel 718 is manufactured by High
Temperature Metals,
Inc. (Telephone: 1-800-500-2141; Web site: www.
http://www.hightempmetals.com).
SUMMARY OF THE INVENTION
The inventor believes that the problem (which is associated with barrels or
conduits used in
metal-molding systems) is not understood by persons of skill in the art.
According to the current
state of the art, molten magnesium alloys are not currently processed above
650 degrees
Centigrade by metal-molding systems or metal injection-molding systems because
the known
2
AMENDED SHEET
PCT/CA2008/001619
CA 02699237 2010-03-11 17 April 2009 17-04-2009
H-7130-0-WO
REVISION CODES SHOWING: PLEASE DISCARD THIS VERSION
state of the art, molten magnesium alloys are not currently processed above
650 degrees
Centigrade by metal-molding systems or metal injection-molding systems because
the known
barrel assemblies include an outer layer that has an Inconel-718 alloy.
Specifically, due to the
chemistry associated with the Inconel-718 alloy, heating of molten magnesium
alloy above
approximately 650 degrees Centigrade is not possible. The problem arises when
attempting to
manufacture thin-walled metallic articles, such as cell-phone housings and/or
computer laptop
cases because the molten magnesium heated to below approximately 650 degrees
Centigrade
tends to have relatively large globular particles (that is, in relation to the
size of the thin-walled
article that is to be molded). The large globular particles tend to become
stuck in the mold
cavity that is configured to mold very thin-walled articles; thus the large
globular particles
disadvantageously prevent or retard the flow of molten magnesium toward the
edges of the
mold cavity. Using molten magnesium heated to below 650 degrees Centigrade
leads to molded
articles that have unacceptable thin-walled properties and/or qualities. It is
extremely
advantageous to manufacture thin-walled articles to be as thin as possible so
that there is a
savings in weight reduction, and also opens the possibility of making even
smaller articles (than
what is currently possible with the state of the art in molding thin-walled
metallic articles).
According to a first aspect of the present invention, there is provided a
metal-molding conduit
assembly (100), including a body (105) being configured to withstand higher
temperatures,
from approximately 30 to approximately 40 degrees Centigrade above
approximately 650
degrees Centigrade for processing a molding material, and the molding material
includes a
molten metallic alloy having a light-metal alloy.
According to a second aspect of the present invention, there is provided a
metal-molding
conduit assembly (100), having a body (105) being configured to withstand
higher
temperatures, from approximately 30 to approximately 40 degrees Centigrade
above
approximately 650 degrees Centigrade for processing a molding material, and
the molding
material includes a molten metallic alloy having a light-metal alloy, the body
(105) having: (i)
an outer shell (102), including an Inconel-720 alloy; and (ii) an inner shell
(104) being fitted
within the outer shell (102), the inner shell (104), including a corrosion-
resistant alloy.
A technical effect, amongst other technical effects, of the aspects of the
present invention is that
the Inconel-720 alloy withstands higher temperatures, from approximately 30 to
approximately
degrees Centigrade above approximately 650 degrees Centigrade for processing a
molten
35 molding material that includes a molten metallic alloy having a light-metal
alloy, such as a
3
AMENDED SHEET
PCT/CA2008/001619
CA 02699237 2010-03-11 17 April 2009 17-04-2009
H-7130-0-WO
articles), and these thinner articles are not possible to manufacture by using
a molding process
that uses conduits and/or barrels operating at temperatures of less than
approximately 650
degrees Centigrade.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the non-limiting embodiments of the present
invention (including
alternatives and/or variations thereof) may be obtained with reference to the
detailed description
of the non-limiting embodiments along with the following drawings, in which:
FIGS. 1A and 1B depict cross sectional views taken along a longitudinal axis
of a metal-
molding conduit assembly 100 (hereafter referred to as the "assembly 100")
according
to a first non-limiting embodiment; and
FIG. 2 is a schematic representation of the assembly 100 according to a second
non-limiting
embodiment, a metal-molding system 200 (hereafter referred to as the "system
200")
according to a third non-limiting embodiment, and a metal injection-molding
system
202 (hereafter referred to as the "system 202") according to a fourth non-
limiting
embodiment.
The drawings are not necessarily to scale and are sometimes illustrated by
phantom lines,
diagrammatic representations and fragmentary views. In certain instances,
details that are not
necessary for an understanding of the embodiments or that render other details
difficult to
perceive may have been omitted.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
FIG. 1A depicts the cross sectional view taken along the longitudinal axis 101
of the assembly
100, in accordance with a first non-limiting variant of the first non-limiting
embodiment. The
system 200 may incorporate the assembly 100. The system 202 may incorporate
the assembly
100. The assembly 100 may be sold with or sold separately from the system 200
or the system
202. A molded article 204 (depicted in FIG. 2) may be manufactured or made by
the system
200 or the system 202 incorporating the assembly 100. The longitudinal axis
101 extends from
an input to an output of the assembly 100. The assembly 100 has an outer shell
102, which
includes an Inconel-720 alloy. The Inconel-720 alloy withstands higher
temperatures, from
approximately 30 to approximately 40 degrees Centigrade above approximately
650 degrees
Centigrade for processing a molding material 103. The molding material 103
includes a molten
4
AMENDED SHEET
PCT/CA2008/001619
CA 02699237 2010-03-11 17 April 2009 17-04-2009
H-7130-0-WO
metallic alloy that has a light-metal alloy. The light-metal alloy includes a
magnesium alloy (for
example). Other alloys, such as zinc, aluminum may be used as well.
According to a non-limiting variant, the assembly 100 includes a body 105 that
is configured to
withstand higher temperatures, from approximately 30 to approximately 40
degrees Centigrade
above approximately 650 degrees Centigrade for processing a molding material,
and the
molding material includes a molten metallic alloy that has a light-metal
alloy.
FIG. 1B depicts the cross sectional view of the assembly 100 in accordance
with a second non-
limiting variant of the first non-limiting embodiment, in which the assembly
100 includes: (i)
the outer shell 102, and (ii) an inner shell 104. The inner shell 104 is
fitted within the outer
shell 102. The inner shell 104 includes a corrosion-resistant alloy, which is
(preferably) wear
resistant. For example, the corrosion-resistant alloy may include a Stellite-
12 alloy.
According to a non-limiting variant, the assembly 100 has the body 105 that is
configured to
withstand higher temperatures, from approximately 30 to approximately 40
degrees Centigrade
above approximately 650 degrees Centigrade for processing a molding material,
and the
molding material includes a molten metallic alloy that has a light-metal
alloy. The body 105
has: (i) the outer shell 102 that includes an Inconel-720 alloy, and (ii) the
inner shell 104 that is
fitted within the outer shell 102. The inner shell 104 includes a corrosion-
resistant alloy.
FIG. 2 is a schematic representation of the assembly 100, the system 200 and
the system 202.
The system 200 or the system 202 may include components that are known to
persons skilled in
the art, and these known components will not be described here; these known
components are
described, at least in part, in the following text books (by way of example):
(i) "erection
Molding Handbook" by Osswald/Turng/Gramann (ISBN: 3-446-21669-2; publisher:
Hanser),
(ii) "Injection Molding Handbook" by Rosato and Rosato (ISBN: 0-412-99381-3;
publisher:
Chapman & Hill), and/or (iii) "Injection Molding Machines" 3fd Edition by
Johannaber (ISBN
3-446-17733-7).
The system 200 (or the system 202) includes (for example): (i) a hopper 210,
(ii) a feed throat
212, (iii) an extruder 108, and (iv) a clamp assembly 217. The hopper 210 is
connected with the
feed throat 212. The feed throat 212 is connected with a barrel assembly 106
of the extruder
108. The extruder 108 may be: (i) a reciprocating-screw (RS) extruder, or (ii)
a two-stage
extruder that has a shooting pot configuration. A molding material (in the
form of chips of
solidified magnesium, for example) is received in the hopper 210, and then the
molding
5
AMENDED SHEET
PCT/CA2008/001619
CA 02699237 2010-03-11 17 April 2009 17-04-2009
H-7130-0-WO
material is conveyed to the interior of the barrel assembly 106 of the
extruder 108 via the feed
throat 212. A screw 107 is received in the interior of the barrel assembly
106. The screw 107 is
used to move or convey the molding material. A screw actuator 109 is attached
to one end of
the screw 107. The screw actuator 109 is used to actuate movement of the screw
107. A
controller 111 is operatively coupled with the screw actuator 109. The
controller 111 is used to
control the screw actuator 109. The screw actuator 109 is used to rotate the
screw 107, so that
the chips of molding material that are received in the barrel assembly 106 may
be conveyed
along the barrel assembly 106 from the feed throat 212 toward an exit of the
barrel assembly
106. Heaters 117 are coupled to the outer surface of the barrel assembly 106.
As the chips are
conveyed along the barrel assembly 106, the heaters 117 are used to melt the
chips into either a
semi-solid state or a liquid state (as may be required). A check valve (not
depicted, but known)
is mounted with a tip of the screw 107, and the check valve is used to collect
a shot of molten
molding material in an accumulation zone of the barrel assembly 106. The
accumulation zone is
located at the exit port of the barrel assembly 106. Once the controller 111
issues an injection
command to the screw actuator 109, the screw actuator 109 linearly translates
the screw 107 so
as to push the molten molding material out from the accumulation zone of the
barrel assembly
106.
According to a non-limiting arrangement (which is depicted in FIG. 2), a mold
114 is used to
mold articles, and the mold 114 includes or defines multiple mold cavities.
For this case, a hot
runner 216 is used, and a nozzle assembly 110 is connected with: (i) the exit
port of the barrel
assembly 106, and (ii) a hot sprue 112. The hot sprue 112 is held or supported
in a fixed or
stationary position by a stationary platen 152. The mold 114 is attached with
the hot runner 216.
The hot runner 216 is attached with the hot sprue 112, so that the molten
molding material may
be conveyed from the barrel assembly 106, to the nozzle assembly 110, to the
hot sprue 112, to
the hot runner 216, and then to the mold cavities of the mold 114,
accordingly.
According to another non-limiting arrangement (which is not depicted), the
mold 114 includes
or defines a single mold cavity. For this case, the hot runner 216 is not
used, and the nozzle
assembly 110 is connected with: (i) the exit port of the barrel assembly 106,
and (ii) the hot
sprue 112. The mold 114 is attached with the hot sprue 112.
The clamp assembly 217 includes: (i) a movable platen 150, (ii) the stationary
platen 152, (iii)
clamp units 154, (iv) rods 156, and (v) nuts 158. The movable platen 150 is
movable relative to
the stationary platen 152, so that the mold 114 may be closed. The clamp units
154 are fixedly
6
AMENDED SHEET
PCT/CA2008/001619
CA 02699237 2010-03-11 17 April 2009 17-04-2009
H-7130-0-WO
mounted to respective corners of the stationary platen 152. The clamp units
154 are used to
apply a clamping force to the mold 114. The nuts 158 are mounted to respective
corners of the
movable platen 150. The rods 156 are coupled with respective clamp units 154.
The rods 156
extend from respective clamp units 154 to respective nuts 158. The nuts 158
are used to lock
the rods 156 relative to the movable platen 150, so that the clamping force
may be transmitted
from the clamp units 154 to the movable platen 150. As well, the nuts 158 are
used to unlock
the rods 156 relative to the movable platen 150, so that the movable platen
150 may be moved
relative to the stationary platen 152.
The mold 114 includes: (i) a movable mold portion 140 (hereafter referred to
as the "portion
140"), and (ii) a stationary mold portion 142 (hereafter referred to as the
"portion 142"). The
portion 140 is mounted to the movable platen 150, so that the portion 140
faces the stationary
platen 152. The portion 142 is mounted to the hot runner 216, and the hot
runner 216 is
mounted to the stationary platen 152, so that the portion 142 faces the
portion 140.
According to an alternative arrangement (not depicted), the hot runner 216 is
not used, and the
portion 140 is mounted to the movable platen 150, and the portion 142 is
mounted to the
stationary platen 152, so that the portion 142 faces the portion 140.
In operation, the movable platen 150 is moved (by a mold-stroking actuator,
which is not
depicted) toward the stationary platen 152 so that the portion 140 may be
closed against the
portion 142. The nuts 158 lock the platens 150, 152 together, so that the
clamp units 154 may
be actuated so as to transmit the clamping force to the mold 114. The clamping
force is used to
prevent the mold 114 from inadvertently releasing (also known as flashing) the
molding
material from the mold 114 as the mold 114 is filled (under pressure) with the
molten molding
material that was prepared and injected by the extruder 108. Once the shot of
molding material
has been collected in the accumulation zone of the barrel assembly 106, the
screw actuator 109
is actuated so as to linearly translate the screw 107 forwardly (which causes
the check valve to
close so as to prevent a backflow of the molten molding material toward the
feed throat 212),
and in this manner the shot of molten molding material may then be ejected
(under pressure)
from the barrel assembly 106, through the nozzle assembly 110, and either: (i)
directly (as
depicted in FIG. 2) to the hot sprue 112, and then to the hot runner 216 and
then to the mold
cavities of the mold 114, or (ii) directly (which is not depicted) to the hot
sprue 112 and then to
the mold cavity defined by the mold 114.
7
AMENDED SHEET
PCT/CA2008/001619
CA 02699237 2010-03-11 17 April 2009 17-04-2009
H-7130-0-WO
Once the molded article 204 is formed and solidified in the mold cavity of the
mold 114, the
clamp units 154 stop applying the clamping force, the nuts 158 are unlocked so
that then the
mold 114 may be broken apart (by application of a mold break force to the mold
114); and then
the movable platen 150 may be moved away from the stationary platen 152, so
that the molded
article 204 may be removed from the mold 114 (either manually or by robot).
According to a non-limiting variant, the outer shell 102 is included in any
one of: (i) the barrel
assembly 106, (ii) the nozzle assembly 110, (iii) the hot sprue 112, (iv) the
mold 114, (v)
components of the hot runner 216, (vi) the screw 107, and/or any combination
and permutation
thereof.
According to another non-limiting variant, the outer shell 102 and the inner
shell 104 are
included in any one of. (i) the barrel assembly 106, (ii) the nozzle assembly
110, (iii) the hot
sprue 112, (iv) the mold 114, (v) components of the hot runner 216, (vi) the
screw 107, and/or
any combination and permutation thereof.
The description of the non-limiting embodiments provides non-limiting examples
of the present
invention; these non-limiting examples do not limit the scope of the claims of
the present
invention. The non-limiting embodiments described are within the scope of the
claims of the
present invention. The non-limiting embodiments described above may be: (i)
adapted,
modified and/or enhanced, as may be expected by persons skilled in the art,
for specific
conditions and/or functions, without departing from the scope of the claims
herein, and/or (ii)
further extended to a variety of other applications without departing from the
scope of the
claims herein. It is to be understood that the non-limiting embodiments
illustrate the aspects of
the present invention. Reference herein to details and description of the non-
limiting
embodiments is not intended to limit the scope of the claims of the present
invention. Other
non-limiting embodiments, which may not have been described above, may be
within the scope
of the appended claims. It is understood that: (i) the scope of the present
invention is limited by
the claims, (ii) the claims themselves recite those features regarded as
essential to the present
invention, and (ii) preferable embodiments of the present invention are the
subject of dependent
claims. Therefore, what is to be protected by way of letters patent are
limited only by the scope
of the following claims:
8
AMENDED SHEET
