Note: Descriptions are shown in the official language in which they were submitted.
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COOLING STRUCTURE OF METAL-MOLDING SYSTEM FOR
SHOT LOCATED DOWNSTREAM OF BLOCKAGE
TECWITCAL 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, (i) a
metal molding conduit
assembly of a metal molding system, (ii) a metal molding system having a metal
molding conduit
assembly, (iii) a metal molding process of a metal molding system, (iv) a
molded article having a
body made by a metal molding process of a metal molding system, (v) a molded
article having a
body made by a metal molding process of a metal molding system and/or (vi) a
mold of a metal
molding system.
BACKGROUND OF THE INVENTION
Molding systems are generally described, at least in part, in the following
text books (by way of
example): (i) "Injection 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 Systems" 3rd
Edition by Johannaber
(ISBN 3-446-17733-7).
U.S. Patent No. 5,040,589 (Filed: 10 February 1989; Inventor: Bradley et al)
discloses forming a
plug of solid metal (in a nozzle of an injection molding machine) from a
residue of molten metal
that remains after a mold cavity is filled. A conduit passageway has a volume
of molten metal
located upstream of a formed metal plug (that is, a blockage). This
arrangement appears to have
become an established approach for configuring molten metal conduit
passageways, and this
approach has not changed since the filing date of this patent (as will be
demonstrated in a review of
the state of the art below). The formed (solid) plug is injected into a mold,
and the plug is caught in
a plug catcher so that the plug is thus prevented from entering the mold
cavity defined by the mold.
The plug becomes a vestige that needs to be removed from the molded article
(in which case, the.
removed plug represents a waste of molding material). For molded articles
having a large size, this
arrangement may or may not represent a problem. However, for smaller molded
articles (such as
cell-phone housings, laptop housings, etc), this arrangement may represent a
problem.
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Published article titled Semi-solid Forming of Aluminum and Magnesium
(Publication date: June
1996;. Author: A.I. "Ed" Nussbaum; Joumal Name: Light Metal ABE) discloses a
mold cavity
which has a catcher that catches a metallic plug so that the plug, once
caught, does not impede the
flow of molten metal into the mold cavity.
PCT Patent Application No. WO/9928065A1 (Filed: 30 November 1998; Inventor:
Murray et al)
discloses a metal molding system that includes a conduit passageway having a
volume of molten
metal located upstream of a plug (that is, a blockage). This arrangement
appears to conform to the
industry-accepted approach for injecting molten metal into a mold cavity.
i0
U.S. Patent No. 6,533,021 (Filed: 14 September 2000; Inventor: Shibata et al)
discloses a metal
molding system that includes a conduit passageway having a volume of molten
metal located
upstream of a plug (that is, a blockage). The plug is.blocked from entering a
mold cavity and then it
becomes partially melted (by a heater) so that molten metal may flow past the
plug. Since the plug is
blocked from entering the mold cavity, the plug partially resists the flow of
molten metal. This
arrangement may reduce the quality of the molded part and/or may increase
cycle time needed to
mold an article. If the plug is melted before injection pressure is applied,
the molten metal begins to
drool (and a potentially low-quality part may be formed). If the plug is
melted after the injection
pressure is applied, the piug may become jammed in an entrance leading into a
mold cavity and then
the plug acts to restrict (at least in part) flow of the molten metal flowing
from upstream toward
downstream and then into the mold cavity (and potentially increase cycle
time). The timing of when
to begin heating the plug (relative to when injection pressure is actuated)
may be difficult to achieve
on a repeatable and reliable basis.
U.S. Patent No. 6,938,669 (Filed: 28 August 2002; Inventor: Suzuki et al)
discloses a metal molding
system that includes a conduit passageway having a volume of molten metal
located upstream of a
plug (that is, a blockage). This arrangement appears to conform to the
industry-accepted approach
for injecting molten metal into a mold cavity.
PCT Patent Application No. WO/03106075A1 (Filed: 5 May 2003; Inventor:
Czerwinski et al)
discloses a metal molding system that includes a conduit passageway having a
volume of molten
metal located upstream of a plug (that is, a blockage). This arrangement
appears to conform to the
industry-accepted approach for injecting molten metal into a mold cavity.
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U.S. Patent Application No. 200510006046A1 (Filed: 10 August 2004; Inventor:
Tanaka et al)
discloses a metal molding system that includes a conduit passageway having a
volume of molten
metal located upstream of a plug (that is, a blockage). An injection pressure
injects the plug, which
is followed by a flow of the volume of molten metal into the mold cavity. The
mold cavity has a
catcher that catches the injected plug so that it remains offset from the
molten metal that flows into
the mold cavity (thereby the plug does not resist or impede the flow). This
arrangement appears to
be an industry-accepted approach that results in a molded article having a
(potentially large) vestige
that includes the plug embedded therein. A large vestige may cause heat
deformation of the molded
part if the vestige is formed on a thin wall (of the molded part) because the
vestige has a thermal
mass which may cool slower than the mass of the thin wall. This arrangement
may result in
increased manufacturing costs since the large vestige represents a waste of
material and/or requires
effort to remove it from the molded article, and/or represents a limit as to
how thin the molded
article can be made.
It appears that the metal molding process as described above (established over
a 15 year period
without apparent deviation) is to pass, through a passageway conduit, a volume
of molten metal that
is located upstream of a passageway blockage (that is, upstream in a sense
that the shot is located
between the plug and an injection unit of the metal molding system), and that
the way to manage the
plug is to catch it in a plug catcher.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a
metal molding conduit
assembly of a metal molding system, the metal molding conduit assembly (200;
406) includes a
cooling structure (290; 490) being positionable proximate of a drop (280; 480)
of a conduit
passageway (202; 402), the drop (280; 480) being connectable to a gate (270;
470) of a mold (214;
424), the conduit passageway (202; 402) being configured to pass a volume of
molten metal (204;
404), the conduit passageway (202; 402) being configured to pass a volume of
molten metal (204;
404) being located downstream of an upstream passageway blockage (206; 416B),
the upstream
passageway blockage (206; 416B) being formable in the conduit passageway (202;
402), the conduit
passageway (202; 402) also being configured to have a downstream blockage
(212; 416C) formable
therein, and the downstream blockage (212; 416C) being located downstream of
the upstream
passageway blockage (206; 416B), and the volume of molten metal (204; 404)
being located
between the downstream blockage (212; 416C) and the upstream passageway
blockage (206; 416B),
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the cooling structure (290; 490) being configured to substantially reduce heat
contained in the
volume of molding material located proximate of the drop (280; 480).
According to a second aspect of the present invention, there is provided a
metal molding system,
having the metal molding conduit assembly as described above.
According to a third aspect of the present invention, there is provided a
metal molding process of
the metal molding system as described above, including positioning a cooling
structure proximate of
a drop of a conduit passageway, the drop connectable to a gate of a mold, the
conduit passageway
configured to pass a volume of molten metal, the cooling structure configured
to substantially
reduce drool of molding material from the drop.
According to a fourth aspect of the present invention, there is provided a
metal molding process of
the metal molding system as described above,. including substantially reduce
drool of molding
material from a drop by actuating a cooling structure being positioned
proximate of the drop of a
conduit passageway, the drop connectable to a gate of a mold, the conduit
passageway configured to
pass a volume of molten metal.
According to a fifth aspect of the present invention, there is provided a
molded article having a body
made by the metal molding process of the metal molding system as descn'bed
above.
According to a sixth aspect of the present invention, there is provided a
molded article having a
body made by the metal molding process as described above.
According to a seventh aspect of the present invention, there is provided a
molded article, including
a body having a metal received from the metal molding conduit assembly of the
metal molding
system as described above.
According to a eighth aspect of the present invention, there is provided, for
the metal molding
system as described above, a mold for forming an article from a metallic
molding material,
including a mold body configured to cooperate with the metal molding conduit
assembly as
described above.
A technical effect of the present invention provides a molding arrangement
that mitigates the
disadvantages associated with the state of the art pertaining to molding, at
least in part.
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BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the exemplary embodiments of the present invention
(including
alternatives and/or variations thereof) may be obtained with reference to the
detailed description of
the exemplary embodiments along with the following drawings, in which:
FIG. 1 is a cross-sectional view of a metal molding conduit assembly 100
according to a first
embodiment;
FIG. 2 is a cross-sectional view of a metal molding conduit assembly 200
according to a
second embodiment;
FIG. 2A is another cross-sectional view of the metal molding conduit assembly
200
according to the second embodiment;
FIG. 3 is a cross-sectional view of a metal molding conduit assembly 300
according to a
third embodiment;
FIG. 4 is a cross-sectional view of a metal molding conduit assembly 400
according to a
fourth embodiment;
FIG. 4A is another cross-sectional view of the metal molding conduit assembly
400
according to the fourth embodiment;
FIG. 5 is a cross-sectional view of a metal molding conduit assembly 500
according to a
fifth embodiment;
FIG. 6 is a cross sectional view of a metal molding conduit assembly 600
according to
a sixth embodiment;
FIG. 6A is another cross sectional view of the metal molding conduit assembly
600
according to the sixth'embodiment; and
FIG. 7 is a cross-sectional view of a metal molding conduit assembly 700
according to
a seventh 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)
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FIG. 1 is a cross-sectional view of a metal molding conduit assembly 100
according to a first
embodiment of the present invention.
The metal molding conduit assembly 100 includes a conduit passageway 104
configured to pass a
volume of molten metal 106 (hereafter referred to as the "volume" 106) located
downstream of a
passageway blockage 108 (hereafter, from time to time, refer to as the
"blockage" 108). The
blockage 108 is formable in the conduit passageway 104.
The conduit passageway 104 is defined, by at least one conduit body member 102
(as depicted in
FIG. 1) or may be defined by a plurality of conduit body members (described in
embodiments
below). The conduit body member 102 is hereafter called the "body.member" 102.
According to the
first embodiment, the conduit body member 102 is a machine nozzle that defmes
the conduit
passageway 104 and it is attached to an injection unit 112. The injection unit
112 is depicted
-schematically. The conduit passageway 104 connects the injection unit 112 to
a mold 118. It is to be
understood that "upstream" is toward the injection unit 112 and "downstream"
is toward the mold
118..
The blockage 1.08 is located upstream relative to the volume of molten metal
106. The metal
molding conduit assembly 100 is used in a metal molding system 110 (not
entirely depicted in FIG.
1). The volume of molten metal 106 is, preferably, proximate or adjacent to
the blockage 108. The
blockage 108 is formable by a blockage-forming mechanism 109 configured to
cooperate with the
conduit passageway 104. The volume of molten metal 106 is also called a
downstream volume of
molten metal 106, and the blockage 108 is also called an upstream blockage 108
The metal molding system 110 includes the injection unit 112 that processes a
molten metal 114.
The molten metal 114 is introduced into the injection unit 112 by a hopper
assembly (not depicted)
that is attached to the injection unit 112. The molten metal 114 exists in a
slurry state that includes a
liquefied-metallic component and a solidified-metallic component, or includes
only the liquefied-
metallic component (in some instances). Preferably, the molten metal 114 is a
thioxtropic metal
having an alloy of magnesium. Other metallic alloys are contemplated, such as
zinc and/or
aluminum, etc) in a liquid state or a slurry state (a slurry state includes
the metal in liquid form
having solid particles of the metal carried therein).
The upstream blockage 108, preferably, is a plug that is formable in the
conduit passageway 104 by
the blockage-forming mechanism 109. The upstream blockage 108 may be a thixo
plug (for
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example), which is formed from a slurry of an alloy of magnesium or other
metal. The upstream
blockage 108 is solidified within the conduit passageway 104 and friction
between the inner wall of
the conduit body member 102 and the outer surface of the upstream blockage 108
frictionally
cooperate to retain the upstream blockage 108 to the inner wall of the conduit
body member 102.
Sometimes the term "welded" is used to describe that the upstream blockage 108
is frictionally
engaged to the conduit passageway 104.
The blockage-forming mechanism 109 provides localized cooling sufficient
enough to form the
blockage 108 in the conduit passageway 104. Preferably the blockage-forming
mechanism 109 is a
cooling mechanism that actively removes heat to form the upstream blockage
108. Alternatively, the
blockage-forming mechanism 109 is a heating mechanism 111 that forms the
upstream blockage
108 by shutting off or reducing generated heat supplied to molten metal
contained in the conduit
passageway 104 (so that the molten metal may cool off when heat is not
supplied thereto). The
blockage-forming mechanism 109 may be distributed and available along a length
of the conduit
passageway 104 to permit forming blockages at different locations along the
conduit passageway
104 to provide differently-sized volumes (of molten metal) for different
molded parts (assuming the
desire to reuse the same conduit for different parts).
The conduit body member 102 has one end connected to the injection unit 112,
and has another end
that leads into a mold cavity 116 of the mold 118. The mold cavity 116 is
located downstream of the
injection unit 112. The mold 118 includes a stationary mold half 120 and a
movable mold half 122.
The injection unit 112 is a source of molten metal, and the mold cavity 116 is
the receiver of the
volume of molten metal 106.
In operation, before the volume of molten metal 106 is injected into the mold
cavity 116, the heating
mechanism 111 actively maintains the volume of molten metal 106 in a
substantially non-drooling
state so that the volume of molten metal 106 does not substantially drool into
the mold cavity 116
before an injection pressure is imposed by the injection unit 112 onto the
volume of molten metal
106. Before the volume of molten metal 106 is injected, the volume of molten
metal 106 facing the
entrance of the mold cavity is exposed to air, oxidizes and may solidify upon
exposure to open air
contained in the mold cavity 116. However, the volume of molten metal 106 does
not necessarily
solidify at the entrance of the mold cavity 116 if enough heat is applied to
the volume of molten
metal 106. Responsive to application of the injection pressure, a stream of
molten metal is made to
flow downstream through the conduit passageway 104. The injected molten metal
114 pushes
against the blockage 108 with sufficient force so that the blockage 108 gives
way and becomes
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moved downstream along the conduit passageway 104. The moving blockage 108
along with the
moving molten metal 114 pushes the volume of molten metal 106 downstream the
conduit
passageway 104 and into the mold cavity 116. For a thin-walled (molded)
article (which is defined
by a thin mold cavity), the blockage 108 is not injected into the mold cavity
116 and it is stopped
s from moving and remains proximate to a downstream egress 126 of the conduit
passageway 104.
For a thick-walled (molded) article (which is defined by a thick mold cavity),
the blockage 108 may
be injected into the mold cavity. The volume of molten metal 106 is large
enough to fill the mold
cavity 116. Once a molded article 128 is cooled sufficiently, the mold halves
120, 122 are actuated
to separate from each other so that the molded article 128 may be extracted
from the mold cavity
116. Before another volume is injected into the mold cavity 116, the blockage
1081ocated at the
downstream egress 126 is melted by the heating mechanism 111 while another
blockage is formed
upstream of the next volume to be injected.
A technical effect of the first embodiment is that this arrangement pemiits
the molded article 128 to
have, advantageously, fewer defects (since the flow of the volume was not
resisted by the blockage
108) and/or less wasted material (since there is no plug catcher that requires
removal from the
molded article 128). The molded article 128 is made with less molten metal
which reduces material
costs and/or material scrap. This molding arrangement provides improving
quality and/or reduced
cost of molding.
The blockage 108, when embodied as the upstream plug, is maintained
frictionally engaged to the
conduit passageway 104 sufficiently enough to resist a molten-metal residual
pressure originating
from the injection unit 112, but the blockage 108 gives way responsive to the
injection pressure
(that is generated by the injection unit 112). The blockage 108 is formable at
a predetermined
position along the conduit passageway 104 to change the size of the volume of
molten metal 106.
The blockage 108 is configured to release from the conduit passageway 104
responsive to the
injection pressure bearing on the blockage 108, travel downstream along the
conduit passageway
104 and become jammed into the downstream egress 126 of the conduit passageway
104. The
jammed blockage 108 bears a pressure spike that originates from the injection
unit 112 sufficiently
enough to substantially prevent the pressure spike from entering the mold
cavity 116 and causing
the volume of molten metal 106 to flash from the mold cavity 116 (once the
volume of molten metal
106 has entered the mold cavity 116). After injection of the volume (at least
in part), the jammed
blockage 108 may be heated into a slurry state or a molten state for the next
injection cycle.
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The molded article 128 includes a body having a vestige 130 that conforms to
the shape of the
downstream egress 126 (at least in part). The body has a show side and a non-
show side. The
vestige 130 is molded on any one of the show side or the non-show side. The
vestige 130 may
remain with the body or may be removed from the body. Preferably, the vestige
130 is surrounded at
least in part by a line of weakness so that the vestige may be removed easily
from the body. The
molded article 128 is (for example) a thin walled product such as a cover of a
laptop computer or a
cover of a cell phone. The vestige 130 is formed or positioned in a central
zone of the body of the
molded article 128. Advantageously, this process may permit a smaller vestige
to be fonned on the
molded part, and if th e molded article has a thin wall on which the vestige
is formed, the thermal
mass of the vestige may cool at the same (near same) rate of that of the thin
wall (thus deformation
of the thin wall may be avoided).
The stationary mold half 120 of the mold 118 defmes a gate entry that leads
into a mold cavity that
has an 18 mm (millimeters) wide diameter. The movable mold half 122 cooperates
with the
stationary mold half 120 to define the mold cavity 116 that is about 0.65 mm
thick. Preferably, the
mold 118 does not form a plug catcher for catching the blockage 108. The gate
entry is positioned in
a central zone of the stationary mold half 120.
The conduit passageway 104 is configured to connect to a metal-molding system,
such as (for
example, but not limited to) a die casting system, a thixo-molding system (for
molding slurry of
metal),.or a metal injection molding system.
In an alternative embodiment, the conduit body member 102 includes a barrel of
the injection unit
112, and the blockage 108 is formable in an area leading out from the barrel.
In an alternative embodiment, the volume of molten metal 106 is a metallic
shot having a volume
equal to a volume of a mold cavity 116.
FIG. 2 is a cross-sectional view of a metal molding conduit assembly 200
according to a second
embodiment of the present invention.
The metal molding conduit assembly 200 includes a conduit passageway 202
configured to pass a
volume of molten meta1204 (hereafter referred to as the "volume" 204)-located
downstream of a
passageway blockage 206 (hereafter, from time to time, referred to as the
"blockage" 206). The
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blockage 206 can be called an upstream passageway blockage 206. The blockage
206 is formable in
the conduit passageway 202.
The metal molding conduit assembly 200 is included in a metal molding system
208 (partially
depicted) having an injection unit 209. The conduit passageway 202 is defined
by body members
210A, 210B that cooperate with each other, and the conduit passageway 202
extends therethrough.
The body member 210A is a hot sprue, and the body member 210B is a machine
nozzle that is
connected to the injection unit 209. The conduit passageway 202 is also
configured to have a
downstream blockage 212 formable therein, and the downstream blockage 212 is
located
downstream of the upstream passageway blockage 206. The volume of molten metal
204 is located
between the downstream blockage 212 and the upstream passageway blockage 206.
The downstream blockage 212 includes a downstream blockage 212 (the downstream
blockage 212
may be a thixo plug), and the upstream passageway blockage 206 includes an
upstream passageway
blockage 206 (passageway blockage 206 may be a thixo plug) both of which are
formable in the
conduit passageway 202. The downstream blockage 212 is formed by a plug
forming mechanism 213. Once the downstream blockage 212 has been formed by the
plug forming mechanism 213 and
then the downstream blockage 212 was moved downstream at a later time during
injection of the
molding material.
The downstream blockage 212, when frictionally engaged to the conduit
passageway 202, prevents
the next volume from drooling out from the conduit passageway 202 prior to
injecting the volume
into a mold cavity of the mold 214. The downstream blockage 212 may be a"sofE"
blockage in that
it does not have to be hard frozen. The downstream blockage 212 is maintained
soft enough so that
the injection pressure can easily dislodge and push the downstream blockage
212 away from the
conduit passageway 202 and into the mold cavity. The downstream blockage 212
is maintained soft
enough to not provide significant resistance upon being forced (or extruded)
to enter a mold cavity
defined by a mold 214. The downstream blockage 212 is maintained soft enough
to be easily
extruded through an entrance of the mold cavity responsive to the downstream
blockage 212
experiencing an injection pressure.
A"thin skinned" plug (that is, the downstream blockage 212) is formed at the
end of the conduit
passageway 202 that leads into a mold after ejection of the molded part from
the mold 214. When
the mold 214 is opened and the molded part removed therefrom, a thin skin of
solidified metal may
form and remain at the end of the conduit passageway 202 and this would assist
in the prevention of
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drool (of the next volume) while the thin skinned solidified plug remains (or
is maintained) soft
enough to be easily pushed into the mold cavity of the mold 214 without much
resistance. In a
sense, the downstream plug is easily extruded into the mold 214 because it
remains in a soft-formed
condition.
Preferably, the upstream passageway blockage 206 is maintained hard enough to
resist becoming
extruded through the egress of the conduit (or the entrance of the old cavity)
responsive to the
blockage 206 experiencing the injection pressure. In an alternative, the
(upstream) blockage 206 is
maintained soft enough to be extruded, at least in part, through an entrance
of the mold cavity
to responsive to the blockage 206 experiencing the injection pressure.
The mold 214 includes a stationary mold half 216 and a movable mold half 218.
The downstream
blockage 212 is formable proximate to an egress end of the conduit passageway
202, and the egress
end is positioned at an entrance of the mold cavity. A heating mechanism 220
maintains the volume
of molten meta1204 in a non-solidified state. Preferably, the downstream
blockage 212 is a soft-
formed plug.
A technical effect of the second embodiment is similar to that of the
technical effect of the first
embodiment.
FIG. 2A is another cross-sectional view of the metal molding conduit assembly
200 according to a
variant of the second embodiment. The metal molding conduit assembly 200 of a
metal molding
system 211 includes a cooling structure 290 that is positionable proximate of
a drop 280 of a
conduit passageway 202. The drop 280 is connectable to a gate 270 of a mold
214. The conduit
passageway 202 is configured to pass a volume of molten metal 204. The cooling
structure 290 is
configured to substantially reduce drool of molding material from the drop
280, such as when the
mold 214 is not being filled with a molding material. The cooling structure
290 may be a cooling
ring, for example, that conveys a cooling fluid (liquid, air, etc) through the
cooling structure 290.
The rate of flow of the cooling fluid permits either a higher or a lower rate
of cooling to the gate 270
and the drop 280. The technical effect of the cooling structure 290 is to
substantially reduce
(preferably eliminate) drool of the molding material from the drop 280. The
downstream blockage
212 is further solidified or softened by a degree of cooling that the cooling
structure 290 may impart
to the downstream blockage 212 when so actuated to do so. The cooling
structure 290 is configured
to substantially relatively reduce heat contained in the volume of molding
material located
proximate of the drop 280.
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FIG. 3 is a cross-sectional view of a metal molding conduit assembly 300
according =to a third
embodiment of the present invention.
The metal molding conduit assembly 300 is usable in a metal molding system 302
(partially
depicted) that has an injection unit 303. The metal molding conduit assembly
300 includes a conduit
passageway 304 configured to pass a volume of molten metal 306 located
downstream of a
passageway blockage 308. The passageway blockage 308 is formable in the
conduit passageway
304.
lo
The conduit passageway 304 is defined by a plurality of body members 310A,
310B and 310C (such
as a hot sprue that is indicated as reference numeral 310A, a cooling
mechanism that is indicated as
reference, numeral 310B, and a machine nozzle that is indicated as reference
numera1310C). The
cooling mechanism provides a cooling effect, a heat sinking effect, and/or a
reduced heating effect.
A mold 312 includes a movable mold half 314 and a stationary mold half 316
that define a mold
cavity 318. The mold 312 includes a mold body that has a hot half and a cold
half. The mold body
includes a runner that connects the mold cavity 318 to an entrance of the mold
body. The mold body
includes a hot runner that connects the mold cavity 318 to an entrance to the
mold body. The
plurality of body members 310A, 310B and 310C is for forming the conduit
passageway 304. If you
mean that this assembly of components could otherwise be called.a "hot runner"
I suggest adding
this statement to make this clear.
A technical effect of the third embodiment is similar to that of the first
embodiment, at least in part.
FIG. 4 is a cross-sectional view of a metal molding conduit assembly 400
according to a fourth
embodiment of the present invention.
The metal molding conduit assembly 400 is part of a molten metal hot runner
assembly 401 that is.
connectable to a metal molding system 403A having an injection unit 403B. A
nozzle 403C
connects the injection unit 403B to the molten metal hot runner assembly 401.
The metal molding
conduit assembly 400 includes a conduit passageway 402 that passes a volume of
molten metal 404
(hereafter referred to as the "volume" 404) located downstream of a passageway
blockage 406. The
passageway blockage 406 is formable in the conduit passageway 402.
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The passageway blockage 406 is used to substantially resist a molten-metal
residual pressure that
originates from injection unit 403B, and that the downstream blockages 416A,
416B, and/or 416C
may be kept (or maintained) in a soft condition and thus not have to resist
the molten metal residual
pressure but may resist drool pressure that originates from molten metal
located between the plugs.
s
The conduit passageway 402 is defined by a conduit body member 408 that forms
a plurality of
drops 410A, 410B that lead to a' mold cavity 412 defined by a mold 424. The
passageway blockage
406, once released from its depicted position, does not interfere with the
flow of molten metal since
it flows along with the molten metal and melts therein before it hits a bend
in the conduit
passageway 402. Alternatively, the hot runner assembly may include a plug
catcher 430 for catching
the plug so that the plug does not disrupt flow of molten metal in to the
branches of the hot runner
assembly (and plug caught in the plug catcher 430 is liquefied by applied
heating).
The conduit passageway 402 has a plurality of downstream blockages 416A, 416B,
416C that are
fonnable therein. The downstream blockages 406, 416A, 416B are formed by
blockage-forming
mechanisms 418A, 418B and 418C respectively. The downstream blockage 416C is
a"soft"
blockage of the type described above in a previous embodiment. The volume of
molten meta1404 is
disposed between the downstream blockages 406, 416A, and 416B. A shot 420A is
disposed in the
drop 410A. A shot 420B is disposed in the drop 410B. Heating mechanisms 422And
422B heat the
shots 420A, 420B respective. A mold 424 includes a movable mold half 426 and a
stationary mold
half 428.
The passageway blockage 406 is pushed into the conduit passageway 402 but the
passageway
blockage 406 is melted (by heating mechanisms that are not depicted) before it
travels further
downstream into any particular branch (either upper or lower branches) of the
conduit passageway
402.
A technical effect of the fourth embodiment is similar to that of the first
embodiment, at least in
part.
FIG. 4A is another cross-sectional view of the metal molding conduit assembly
400 according to a
variant of the fourth embodiment. A metal molding conduit assembly 400 of a
metal molding
system 411 includes cooling structures 490, 492 that are positionable
proximate of drops 481, 480
respectively of a conduit passageway 402. The drops 481, 480 are connectable
to gates 471; 470
respectively of a mold 424. The conduit passageway 402 is configured to pass a
volume of molten
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meta1404. The cooling structures 490, 492 are configured to substantially
reduce drool of molding
material from the drops 481, 482 respectively. The cooling structures 490, 492
(which may be
cooling ring, etc) convey a cooling fluid (liquid or air, etc). The rate of
flow of the cooling fluid
through the cooling structures 490, 492 permit either a higher or a lower rate
of cooling to the
respective gates. The technical effect of the cooling structures 490, 492 is
to substantially reduce
(preferably eliminate) drool of the molding material from the respective gate.
The downstream
blockage 416C is further solidified or softened by the degree of cooling,that
the cooling structure
490 may impart to the downstream blockage 416C.
FIG. 5 is a cross-sectional view of a metal molding conduit assembly 500
according to a fiffth
embodiment of the present invention.
The metal molding conduit assembly 500 includes a conduit passageway 502
configured to pass a
volume of molten metal 5041ocated downstream of a passageway blockage 506. The
passageway
blockage 506 is formable in the conduit passageway 502.
The conduit passageway is 502 is defined by opposed hot sprues 508A, 508B
which are part of a hot
sprue assembly, otherwise called a stack mold assembly. The conduit passageway
502 is defmed by
hot sprues 508A, 508B. A hot runner assembly 510 connects one of the hot
sprues (508A) to the
molds 512A, 512B, 512C, and 512D via branches of a hot mmmer assembly. The hot
sprues 508A,
508B are separable from each other when molds 512A, 512B, 512C, and 512D are
opened.
Blockages 509A, 509B in the hot sprues 508A, 508B are maintained soft enough
to separate from
each other and continue remaining within each of their hot sprues 508A, 508B
once they have been
separated from each other. A machine nozzle 514 is connected from a metal
molding system to the
hot sprue 508B.
A technical effect of the fifth embodiment is similar to that of the first
embodiment at least in part.
FIG. 6 is a metal molding conduit assembly 600 according to a sixth embodiment
of the present
invention. The metal molding conduit assembly 600 includes a conduit
passageway 602 configured
to pass a volume of molten metal 604 located upstream of a passageway blockage
606 that is
formable in the conduit passageway 602. The passageway blockage 606 is
maintained to engage the
conduit passageway 602 sufficiently enough to prevent the volume of molten
metal 604 from
drooling out from the conduit passageway 602 prior to the passageway blockage
606 experiencing
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an injection pressure (applied by a metal-molding system 612 by an in
injection mechanism or by
gravity, etc). The passageway blockage 606 is maintained to remain (or is
maintained) soft enough
to be pushed past through an entrance of a mold cavity 608 in response to the
passageway blockage
606 experiencing an injection pressure that becomes applied to the passageway
blockage 606.
The passageway blockage 606 is maintained soft enough so that an injection
pressure is sufficient
enough to dislodge and push the passageway blockage 606 away from the conduit
passageway and
into the mold cavity 608 of a mold 616. The passageway blockage 606 is
fomiable by a blockage-
forming mechanism 610 that is configured to cooperate with the conduit
passageway 602 (such as a
cooling ring, ete). The passageway blockage 606 includes, preferably, a plug
that is formable in the
conduit passageway 602 by the blockage-forming mechanism 610. The passageway
blockage 606
may also be a thixo plug (as used in conjunction with thixo molding systems).
Heater 692 is used to
maintain the heating of the shot while the shot is waiting to be injected into
the mold cavity of the
mold 616.
At least one body member 614 defmes the conduit passageway 602. The body
member 614 is or
includes, preferably, a machine nozzle that is attachable to the metal-molding
system 612.
Alternatively, the conduit passageway 602 is defined by a plurality of body
members.
The volume of molten metal 604 (also called a shot) is injected into the mold
616 (at least in part).
The mold 616 is, preferably, passageway-blockage receiverless (that is, the
mold 616 does not have
a blockage catcher for receiving a blockage therein). The volume of molten
metal 604 is (for
example) a metallic shot having a volume equal to a volume of a mold cavity
608.
The conduit passageway 602 is configured to connect to the metal-molding
system 612 (examples
of which. are, but not limited to, a thixo-molding system, a die casting
system, and/or a metal
injection molding system, etc).
A technical effect of the sixth embodiment is similar to that of the first
erimbodiment, at least in part.
FIG. 6A is another cross sectional view of the metal molding conduit assembly
600 according to a
variant of the sixth embodiment. A metal molding conduit assembly 600 of a
metal-molding system
611 includes a cooling structure 690 that is positionable proximate of a drop
680 of a conduit
passageway 602. The drop 680 is connectable to a gate 670 of a mold 616. The
conduit passageway
602 is configured to pass a volume of molten metal 604. The cooling structure
690 is configured to
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substantially reduce drool of molding material from the drop 680. The cooling
structure 690 (such
as a cooling ring) conveys a cooling fluid (liquid, air, etc) through the
cooling structure 690. The
rate of flow of the cooling fluid permits either a higher or a lower rate of
cooling to the gate. The
technical effect of the cooling structure 690 is to substantially reduce
(preferably eliminate) drool of
the molding material from the gate. The downstream passageway blockage 606 is
further solidified
or softened by the degree of cooling that the cooling structure 690 may impart
to the downstream
passageway blockage 606. Heater 692 is used to maintain the heating of the
shot of the molten metal
604 while the shot is waiting to be injected into the mold cavity of the mold
616.
FIG. 7 is a cross-sectional view of a metal molding conduit assembly 700
according to a seventh
embodiment of the present invention.
The metal molding conduit assembly 700 includes a conduit passageway 702
configured to pass a
volume of molten metal 704 located downsbream of a mechanical valve 706 that
is not operatively
connected to an injection unit 708 of a metal-molding system 710.
At least one body member 712 defines the conduit passageway 702. The body
member 712,
preferably, is or includes a machine nozzle that is attachable to the metal-
molding system 710.
Alternatively, the conduit passageway 702 is defined by a plurality of body
members.
In operation, the metal-molding system 710 is actuated to apply an injection
pressure (by an
injection mechanism or by gravity, etc), and then the mechanical valve 706 is
actuated to open. In
response to the application of the injection pressure, the volume of molten
metal 704 is injected into
a mold cavity 716 of a mold 714 (at least in part), and then the mechanical
valve 706 is actuated to
close. The mold 714 is, preferably, passageway-blockage receiverless (that is,
the mold 714 does not
have a blockage catcher for receiving a blockage therein regardless of whethcr
or not a blockage or
a plug was or was not formed in the conduit passageway 702). The volume of
molten metal 704 is
(for example) a metallic shot having a volume equal to a volume of the mold
cavity 716.
The conduit passageway 702 is configured to connect to the metal-molding
system 710 (examples
of which are, but not limited to, a thixo-molding system, a die casting
system, and/or a metal
injection molding system).
A technical effect of the seventh embodiment is similar to that of the first
embodiment, at least in
part.
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The description of the exemplary embodiments provides examples of the present
invention, and
these examples do not limit the scope of the present invention. It is
understood that the scope of the
present invention is limited by the claims. The concepts described above may
be adapted for
specific conditions and/or functions, and may be further extended to a variety
of other applications
that are within the scope of the present invention. Having thus described the
exemplary
embodiments, it will be apparent that modifications and enhancements are
possible without
departing from the concepts as described. Tberefore, what is to be protected
by way of letters patent
are limited only by the scope of the following claims:
AMENIDED SHEET
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