CA1165525A - Heated nozzle bushing with fixed spiral blade - Google Patents
Heated nozzle bushing with fixed spiral bladeInfo
- Publication number
- CA1165525A CA1165525A CA000370734A CA370734A CA1165525A CA 1165525 A CA1165525 A CA 1165525A CA 000370734 A CA000370734 A CA 000370734A CA 370734 A CA370734 A CA 370734A CA 1165525 A CA1165525 A CA 1165525A
- Authority
- CA
- Canada
- Prior art keywords
- outlet
- injection molding
- spiral blade
- blade member
- core portion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000001746 injection moulding Methods 0.000 claims abstract description 21
- 238000010438 heat treatment Methods 0.000 claims abstract description 19
- 238000005485 electric heating Methods 0.000 claims abstract description 3
- 230000007797 corrosion Effects 0.000 claims description 11
- 238000005260 corrosion Methods 0.000 claims description 11
- 230000007423 decrease Effects 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000004020 conductor Substances 0.000 claims description 3
- 230000003247 decreasing effect Effects 0.000 claims description 3
- 239000000155 melt Substances 0.000 abstract description 20
- 238000000465 moulding Methods 0.000 abstract description 8
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 5
- 239000010935 stainless steel Substances 0.000 abstract description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052802 copper Inorganic materials 0.000 abstract description 3
- 239000010949 copper Substances 0.000 abstract description 3
- 229910000831 Steel Inorganic materials 0.000 abstract description 2
- 239000010959 steel Substances 0.000 abstract description 2
- 238000001816 cooling Methods 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229940090044 injection Drugs 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002991 molded plastic Substances 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000007712 rapid solidification Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/27—Sprue channels ; Runner channels or runner nozzles
- B29C45/30—Flow control means disposed within the sprue channel, e.g. "torpedo" construction
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/27—Sprue channels ; Runner channels or runner nozzles
- B29C45/30—Flow control means disposed within the sprue channel, e.g. "torpedo" construction
- B29C2045/308—Mixing or stirring devices
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to a nozzle bushing for a sprue gated injection molding system. The elongated nozzle bushing has a hollow stainless steel inner core portion through which extends the runner passage from the molding machine to the cavity gate and around which is located a helical electric heating element. A highly conductive copper portion is cast over the heating element and the inner core portion, and covered by a stainless steel outer sleeve. A steel spiral blade member is fixed in the runner passage to impart a curving or swirling motion to the melt as it flows from the gate into the cavity.
This provides the advantage of improving product strength by reducing unidirectional molecular orientation of the melt, as well as reducing stringing of the melt when the mold opens to eject the product.
This invention relates to a nozzle bushing for a sprue gated injection molding system. The elongated nozzle bushing has a hollow stainless steel inner core portion through which extends the runner passage from the molding machine to the cavity gate and around which is located a helical electric heating element. A highly conductive copper portion is cast over the heating element and the inner core portion, and covered by a stainless steel outer sleeve. A steel spiral blade member is fixed in the runner passage to impart a curving or swirling motion to the melt as it flows from the gate into the cavity.
This provides the advantage of improving product strength by reducing unidirectional molecular orientation of the melt, as well as reducing stringing of the melt when the mold opens to eject the product.
Description
~ ~ ~5~;~ 5 BACKGROUND OF I'HE INVENTION
This invention relates to injeckion molding and more particularly to an improved electrically heated nozzle bushing which imparts a curving motion -to the melt en-tering the cavity.
It is well known that molecular orientation effec-ts the strength of injec-tion molded plastic products. Orientation is generally thought to be caused by flow of polymer in the direction of least resis-tance where stresses induced are generally parallel to the flow direction. This resulting uni-directional orientation causes the molded product to be strongerto resist bending forces along the direction of orientation and weaker to resist bending forces across the direction of orien-tation. For instance, a center-gated coffee cup would be stronger in the vertical direction, but very weak in the hoop direction. On the other hand, it is well known to form plastic film with a biaxial molecular orientation to improve its strength characteristics.
More recently, rotation of the mold has been used in injection molding to form the product with a biaxial or multi-axial molecular orientation. While this has been successfulin achieving increased product strenyth, it is not a practical solution to the problem because of diFficul-ties in constructing and operating the spinning molds. It is not suitable for multicavity application, and is very difficult for irregular shaped products.
Even more recently, attempts have been made to achieve biaxial or multiaxial molecular orientation by designing the mold cavity to provide the inflowing melt with an irregular flow pattern. This has usually been in the form of ribs or other shapes against which the incoming melt impinges to spread or , ,~;
1 disperse it in different directions. While having better resulks in terms of increased product strength, this method or concept, of course, has the disadvantage that the product must include the ribs or other shapes introduced into the design to provide this ~illing action. Needless to say, this is not satisfactory for a large range or products.
~ he applicant's copending Canadian application serial number 35~,3~9 filed May 21, 1980 discloses an injection molding system with an improved nozzle tip portion to overcome these problems, but it is for valve-gating. Sprue gated systems have traditionally had the problem or concern o~ reducing or elimi-nating str.inging of the melt from the gate when the mold opens to eject the product from the cavity~
SU~MARY OF THE INVENTION
.
Accordingly, it is an object of the present invention to at least partially overcome these disadvantages by provlding an injection molding nozzle system wherein a swirling motion is imparted to the melt entering the cavity to reduce unidirectional molecular orientation of the molded product.
To this end, in one o~ its aspects, the invention provides an injection molding nozzle bushing comprising: a hollow elongated body having a runner passage extending longi-tudinally therethrough fxom an inlet to an outlet at opposite ends thereof; elongated heating means adapted to heat the elongated body; and a spiral blade member fixed in position in the runner passage to extend to the outlet thereof.
In another of its aspects, the invention provides an injection molding nozzle bushing comrpising: a hollow elongated inner core portion having an inn~r surface defining a generally 3~ cylindrical central runner passage extending longitudinally
This invention relates to injeckion molding and more particularly to an improved electrically heated nozzle bushing which imparts a curving motion -to the melt en-tering the cavity.
It is well known that molecular orientation effec-ts the strength of injec-tion molded plastic products. Orientation is generally thought to be caused by flow of polymer in the direction of least resis-tance where stresses induced are generally parallel to the flow direction. This resulting uni-directional orientation causes the molded product to be strongerto resist bending forces along the direction of orientation and weaker to resist bending forces across the direction of orien-tation. For instance, a center-gated coffee cup would be stronger in the vertical direction, but very weak in the hoop direction. On the other hand, it is well known to form plastic film with a biaxial molecular orientation to improve its strength characteristics.
More recently, rotation of the mold has been used in injection molding to form the product with a biaxial or multi-axial molecular orientation. While this has been successfulin achieving increased product strenyth, it is not a practical solution to the problem because of diFficul-ties in constructing and operating the spinning molds. It is not suitable for multicavity application, and is very difficult for irregular shaped products.
Even more recently, attempts have been made to achieve biaxial or multiaxial molecular orientation by designing the mold cavity to provide the inflowing melt with an irregular flow pattern. This has usually been in the form of ribs or other shapes against which the incoming melt impinges to spread or , ,~;
1 disperse it in different directions. While having better resulks in terms of increased product strength, this method or concept, of course, has the disadvantage that the product must include the ribs or other shapes introduced into the design to provide this ~illing action. Needless to say, this is not satisfactory for a large range or products.
~ he applicant's copending Canadian application serial number 35~,3~9 filed May 21, 1980 discloses an injection molding system with an improved nozzle tip portion to overcome these problems, but it is for valve-gating. Sprue gated systems have traditionally had the problem or concern o~ reducing or elimi-nating str.inging of the melt from the gate when the mold opens to eject the product from the cavity~
SU~MARY OF THE INVENTION
.
Accordingly, it is an object of the present invention to at least partially overcome these disadvantages by provlding an injection molding nozzle system wherein a swirling motion is imparted to the melt entering the cavity to reduce unidirectional molecular orientation of the molded product.
To this end, in one o~ its aspects, the invention provides an injection molding nozzle bushing comprising: a hollow elongated body having a runner passage extending longi-tudinally therethrough fxom an inlet to an outlet at opposite ends thereof; elongated heating means adapted to heat the elongated body; and a spiral blade member fixed in position in the runner passage to extend to the outlet thereof.
In another of its aspects, the invention provides an injection molding nozzle bushing comrpising: a hollow elongated inner core portion having an inn~r surface defining a generally 3~ cylindrical central runner passage extending longitudinally
2 --~ ~ ~5~25 1 therethrough from an inlet to an outlet at opposite ends thereof, the core portion being formed of a high strenyth, corrosion resistant thermally conductive material; an elongated electric heating element extending around the inner core portion; an elongated conductive portion cast on the i.nner core portion and the heating element to be bonded to them a:Long at least a portion of their lengths; and a spiral blade member fixed in position in the central runner passage to extend to the outlet thereof.
In yet another of its aspects, the invention further 1~ provides an injection molding nozzle bushing comprising: a hollow elongated inner core portion having an inner surface defining a central runner passage exten~ing longitudina:Lly therethrough from an inlet to an outlet at opposite ends thereof, the centxal runner passage being generally cylindrical with a tapered portion which gradually decreases in diameter towards the outlet, the inner core portion being formed of a high strength, corrosion resistant, thermally conductive metal; an electrically insulated helical heating element having a plurality of spaced coils encircling the inner core portion and terminal means adapted to receive electric power from an external source;
an elongated conductive portion cast on the inner core portion and the heating element to be bonded to them along their lengths, the conductive portion being formed of a metal having a high thermal conductivity; a spiral blade member extending in the central runner passage from the inlet to the outlet, the sprial blade member being attached along its edges to the inner surface of ~he inner core portion, the spiral blade member being formed of corrosion resistant material and gradually decreasing in pitch and thickness adjacent the outlet; an elongated outer sleeve portion formed of a corro~ion resistant metal extending ~ 3 65525 1 around the conductive portion; and retaining means adapted to retain the nozzle bushing against rotation.
Further objects and advantages of the invention will appear from the ~ollowing description, taken together with the accompanying drawings~
BRIEF DESCRIPTION OF THE DR~WINGS
.
Figure 1 is a partial cut-away perspective view of an injection molding system having a nozzle bushing according to a preferred embodiment of the invention; and Figure 2 is a sectional view of the same embodiment.
DESCRIPTION OF THE PREFERRED E~BODIMENT
. . ~
Referring to the drawings, the injection molding system has a nozzle bushing 10 which is seated in a cavity plate 12 and a back plate 14. The nozzle bushing 10 provides a hot runner passage 16 through which hot pressurized melt flows from a molding machine (not shown) to a cavity 18.
The nozzle bushing 10 has an inner core portion 20 with an inner surface 22 which forms the hot runner passage 16 extending from an inlet 24 to an outlet 26 which is the gate to the cavity 18. As may be seen, the passage 16 is generally cylindrical except for a beveled portion 28 at khe inlet 24 to receive the molding machine and a tapered portion 30 at the outlet 26. Surrounding the inner core portion 20 is an electric helical heating element 32 which is cast in a conductive portion 34. The heating element 32 is insulated from the surrounding material and in this embodiment is shown as of double core construction extending to an external lead 36 for connection to a source.of electric power (not shown). The coils of the heating element 32 are separated from each other to provide for maximum bonding of the conductive material forming conductive .
;
I ~ ~5~25 1 portion 34 to the surface of the coils as well as to the outer surface 38 of the inner core portion 20. An outer slee~e portion 40 around ~he conductive portion 34 provides a corrosion resistant outer finish.
The nozzle bushing lO also includes a spiral blade member 42 which extends through the hot runner passage 16 from the inlet 24 to the outlet or gate 26~ The spiral blade member 42 is brazed along its outer edges 44 to the inner surface 22 of the inner core portion 20 to securely fix it in position. The 1~ blade member is formed of sufficient thickness to ensure it does not rupture during use, but its thickness is gradually reduced adjacent the outlet 26 to minimize the restriction when the melt passes through the tapered portion 30 and the gate 26.
Furthermore, the blade member spiral gradually decreases in pitch in this same area to increase the swirling motion imparted to the melt as it enters the cavity.
The nozzle bushing 10 is securely mounted in the cavity plate 12 and back plate l~ by insulation bushing portion 46. The cavity plate 12 which is cooled by cooling element 48 ~ is separated from the heated nozzle bushing 10 by air gaps 50 to reduce heat losses. The outer end 52 of a pin 54 seated in a hole 56 in the nozzle bushing lO is received in a slot 58 in the back plate 14 in order to prevent rotation of the nozzle bushing by the force of the melt on the spiral blade member 42.
In use, the nozzle bushing lO is located in the mold between the molding machine and the cavity 18. Power is applied to the heating element 32 through lead 36 and operation commences after the nozzle bushing is heated up. Pressurized melt rom the molding machine is injected through the hot runne:r passage 16. Melt pressure is applied from the molding machine in 1 ~ ~i552S
1 impulses. After the application of each pressure impulse to fill the cavity, the melt solidifies in the area of the gate 26 and the mold is opened to eject the molded product and then closed again before the next pressure impulseO Temperature control is very critical to dependable operation, particularly in the gate area. SuEficient heat must be provided by the heating element 32 to maintain smooth, even melt flow, without preventing the cooling element 48 from cooling the cavity and gate sufficiently to provide for rapid solidification and ejection. When a pressure impulse is applied, the melt flows rapidly through the not runner passage 16 and the spiral shape of the blade member 42 imparts a swirling motion to the melt as it passes through the gate 26 into the cavity 18. This swirling motion of the melt through the gate is accelerated by the gradually decreasing pitch of the spiral blade member so that it lS carried as far as possible into the cavity 18 to provide the whole product with the increased strength resulting from unidirectional moledular orientation of the melt being avoided.
In addition, this curving motion of the melt as it leaves the gate has the effect of reducing stringing of the melt when the mold opens to eject the product, presumably because the molecular orientation of the melt is no longer generally perpendicular to the parting line.
In the preferred embodiment, the inner core portion 20 is formed of a corrosion resistant material such as stainless steel to withstand corrosive effects of some melts, as well as to provide the necessary strength. The outer sleeve portion 40 is also formed of stainless steel to provide a durable finish and to withstand any corrosive gases escaping from the gate area.
The spiral blade member 42 is formed of high strength steel and ~ ~ ~;5525 1 the conductive portion 34 is formed of copper which is cast over the heating element 32 and ~ereby bonded to the surface of the coils as well as to the outer surface 38 of the inner core portion 20. The copper is highly conductive and this integral structure provides ~or the rapid transfer of heat from the coils of the heating element 32 and its generally uniform application to the outer surface 38 of the inner core portion 20. This structure provides the necessary strength to withstand the repeated high pressure loading while allowing the thickness of the lesser conductive inner core portion 20 to be minimized.
Thus there is uniform heat application to the melt along the length of the nozzle bushing, while avoiding temperature build-ups which could result in the heating element burning-out or deterioration of the melt. The surfaces of the stainless steel blade member 42 are smooth to reduce friction losses with tha melt as well as to avoid any "dead spots".
Although the description of this invention has been given with respect to a single embodiment, it is not to be construed in a limiting sense. Many variations and modifications will now occur to those skilled in the art. In particular, other blade configurations could be used, for instance only having it extend along part of the length of the hot runner passage 16 ending at the gate 26. Additional pins 54 or other means could be used to prevent rotation of the nozzle bushing, and alternate materials could be used for various molding appli-cations. For a definition of the invention, reference is made to the appended claims.
In yet another of its aspects, the invention further 1~ provides an injection molding nozzle bushing comprising: a hollow elongated inner core portion having an inner surface defining a central runner passage exten~ing longitudina:Lly therethrough from an inlet to an outlet at opposite ends thereof, the centxal runner passage being generally cylindrical with a tapered portion which gradually decreases in diameter towards the outlet, the inner core portion being formed of a high strength, corrosion resistant, thermally conductive metal; an electrically insulated helical heating element having a plurality of spaced coils encircling the inner core portion and terminal means adapted to receive electric power from an external source;
an elongated conductive portion cast on the inner core portion and the heating element to be bonded to them along their lengths, the conductive portion being formed of a metal having a high thermal conductivity; a spiral blade member extending in the central runner passage from the inlet to the outlet, the sprial blade member being attached along its edges to the inner surface of ~he inner core portion, the spiral blade member being formed of corrosion resistant material and gradually decreasing in pitch and thickness adjacent the outlet; an elongated outer sleeve portion formed of a corro~ion resistant metal extending ~ 3 65525 1 around the conductive portion; and retaining means adapted to retain the nozzle bushing against rotation.
Further objects and advantages of the invention will appear from the ~ollowing description, taken together with the accompanying drawings~
BRIEF DESCRIPTION OF THE DR~WINGS
.
Figure 1 is a partial cut-away perspective view of an injection molding system having a nozzle bushing according to a preferred embodiment of the invention; and Figure 2 is a sectional view of the same embodiment.
DESCRIPTION OF THE PREFERRED E~BODIMENT
. . ~
Referring to the drawings, the injection molding system has a nozzle bushing 10 which is seated in a cavity plate 12 and a back plate 14. The nozzle bushing 10 provides a hot runner passage 16 through which hot pressurized melt flows from a molding machine (not shown) to a cavity 18.
The nozzle bushing 10 has an inner core portion 20 with an inner surface 22 which forms the hot runner passage 16 extending from an inlet 24 to an outlet 26 which is the gate to the cavity 18. As may be seen, the passage 16 is generally cylindrical except for a beveled portion 28 at khe inlet 24 to receive the molding machine and a tapered portion 30 at the outlet 26. Surrounding the inner core portion 20 is an electric helical heating element 32 which is cast in a conductive portion 34. The heating element 32 is insulated from the surrounding material and in this embodiment is shown as of double core construction extending to an external lead 36 for connection to a source.of electric power (not shown). The coils of the heating element 32 are separated from each other to provide for maximum bonding of the conductive material forming conductive .
;
I ~ ~5~25 1 portion 34 to the surface of the coils as well as to the outer surface 38 of the inner core portion 20. An outer slee~e portion 40 around ~he conductive portion 34 provides a corrosion resistant outer finish.
The nozzle bushing lO also includes a spiral blade member 42 which extends through the hot runner passage 16 from the inlet 24 to the outlet or gate 26~ The spiral blade member 42 is brazed along its outer edges 44 to the inner surface 22 of the inner core portion 20 to securely fix it in position. The 1~ blade member is formed of sufficient thickness to ensure it does not rupture during use, but its thickness is gradually reduced adjacent the outlet 26 to minimize the restriction when the melt passes through the tapered portion 30 and the gate 26.
Furthermore, the blade member spiral gradually decreases in pitch in this same area to increase the swirling motion imparted to the melt as it enters the cavity.
The nozzle bushing 10 is securely mounted in the cavity plate 12 and back plate l~ by insulation bushing portion 46. The cavity plate 12 which is cooled by cooling element 48 ~ is separated from the heated nozzle bushing 10 by air gaps 50 to reduce heat losses. The outer end 52 of a pin 54 seated in a hole 56 in the nozzle bushing lO is received in a slot 58 in the back plate 14 in order to prevent rotation of the nozzle bushing by the force of the melt on the spiral blade member 42.
In use, the nozzle bushing lO is located in the mold between the molding machine and the cavity 18. Power is applied to the heating element 32 through lead 36 and operation commences after the nozzle bushing is heated up. Pressurized melt rom the molding machine is injected through the hot runne:r passage 16. Melt pressure is applied from the molding machine in 1 ~ ~i552S
1 impulses. After the application of each pressure impulse to fill the cavity, the melt solidifies in the area of the gate 26 and the mold is opened to eject the molded product and then closed again before the next pressure impulseO Temperature control is very critical to dependable operation, particularly in the gate area. SuEficient heat must be provided by the heating element 32 to maintain smooth, even melt flow, without preventing the cooling element 48 from cooling the cavity and gate sufficiently to provide for rapid solidification and ejection. When a pressure impulse is applied, the melt flows rapidly through the not runner passage 16 and the spiral shape of the blade member 42 imparts a swirling motion to the melt as it passes through the gate 26 into the cavity 18. This swirling motion of the melt through the gate is accelerated by the gradually decreasing pitch of the spiral blade member so that it lS carried as far as possible into the cavity 18 to provide the whole product with the increased strength resulting from unidirectional moledular orientation of the melt being avoided.
In addition, this curving motion of the melt as it leaves the gate has the effect of reducing stringing of the melt when the mold opens to eject the product, presumably because the molecular orientation of the melt is no longer generally perpendicular to the parting line.
In the preferred embodiment, the inner core portion 20 is formed of a corrosion resistant material such as stainless steel to withstand corrosive effects of some melts, as well as to provide the necessary strength. The outer sleeve portion 40 is also formed of stainless steel to provide a durable finish and to withstand any corrosive gases escaping from the gate area.
The spiral blade member 42 is formed of high strength steel and ~ ~ ~;5525 1 the conductive portion 34 is formed of copper which is cast over the heating element 32 and ~ereby bonded to the surface of the coils as well as to the outer surface 38 of the inner core portion 20. The copper is highly conductive and this integral structure provides ~or the rapid transfer of heat from the coils of the heating element 32 and its generally uniform application to the outer surface 38 of the inner core portion 20. This structure provides the necessary strength to withstand the repeated high pressure loading while allowing the thickness of the lesser conductive inner core portion 20 to be minimized.
Thus there is uniform heat application to the melt along the length of the nozzle bushing, while avoiding temperature build-ups which could result in the heating element burning-out or deterioration of the melt. The surfaces of the stainless steel blade member 42 are smooth to reduce friction losses with tha melt as well as to avoid any "dead spots".
Although the description of this invention has been given with respect to a single embodiment, it is not to be construed in a limiting sense. Many variations and modifications will now occur to those skilled in the art. In particular, other blade configurations could be used, for instance only having it extend along part of the length of the hot runner passage 16 ending at the gate 26. Additional pins 54 or other means could be used to prevent rotation of the nozzle bushing, and alternate materials could be used for various molding appli-cations. For a definition of the invention, reference is made to the appended claims.
Claims (12)
1. An injection molding nozzle bushing comprising;
(a) a hollow elongated body having a runner passage extending longitudinally therethrough from an inlet to an outlet at opposite ends thereof;
(b) elongated heating means adapted to heat the elongated body; and (c) a spiral blade member fixed in position in the runner passage to extend to the outlet thereof.
(a) a hollow elongated body having a runner passage extending longitudinally therethrough from an inlet to an outlet at opposite ends thereof;
(b) elongated heating means adapted to heat the elongated body; and (c) a spiral blade member fixed in position in the runner passage to extend to the outlet thereof.
2. An injection molding nozzle bushing comprising:
(a) a hollow elongated inner core portion having an inner surface defining a generally cylindrical central runner passage extending longitudinally therethrough from an inlet to an outlet at opposite ends thereof, the core portion being formed of a high strength, corrosion resistant thermally conductive material;
(b) an elongated electric heating element extending around the inner core portion;
(c) an elongated conductive portion cast on the inner core portion and the heating element to be bonded to them along at least a portion of their lengths; and (d) a spiral blade member fixed in position in the central runner passage to extend to the outlet thereof.
(a) a hollow elongated inner core portion having an inner surface defining a generally cylindrical central runner passage extending longitudinally therethrough from an inlet to an outlet at opposite ends thereof, the core portion being formed of a high strength, corrosion resistant thermally conductive material;
(b) an elongated electric heating element extending around the inner core portion;
(c) an elongated conductive portion cast on the inner core portion and the heating element to be bonded to them along at least a portion of their lengths; and (d) a spiral blade member fixed in position in the central runner passage to extend to the outlet thereof.
3. An injection molding nozzle bushing as claimed in claim 2 wherein the spiral blade member is secured to the inner surface of the inner core portion and extends from the inlet to the outlet.
4. An injection molding nozzle bushing as claimed in claim 3 further comprising:
e) an elongated outer sleeve portion formed of a corrosion resistant material extending around the elongated conductive portion.
e) an elongated outer sleeve portion formed of a corrosion resistant material extending around the elongated conductive portion.
5. An injection molding nozzle bushing as claimed in claim 21 3 or 4 further comprising receiving means adapted to receive retaining means to retain the nozzle bushing against rotation.
6. An injection molding nozzle bushing as claimed in claim 2, 3 or 4 wherein the heating element is helical, having a plurlaity of spaced coils encircling the inner core portion with terminal means adapted to receive electrical power from an external source.
7. An injection molding nozzle bushing as claimed in claim 2 wherein the central runner passage has a tapered portion which gradually decreases in diameter towards the outlet.
8. An injection molding nozzle bushing as claimed in claim 2 wherein the spiral blade member gradually decreases in pitch adjacent the outlet of the central runner passage.
9. An injection molding nozzle hushing as claimed in claim 7 wherein the spiral blade member gradually decreases in pitch adjacent the outlet of the central runner passage.
10. An injection molding nozzle bushing as claimed in claim 2, 4 or 9 wherein the spiral blade member gradually decreases in thickness adjacent the outlet of the central runner passage.
11. An injection molding nozzle bushing comprising:
(a) a hollow elongated inner core portion having an inner surface defining a central runner passage extending longitudinally therethrough from an inlet to an outlet at opposite ends thereof, the central runner passage being generally cylindrical with a tapered portion which gradually decreases in diameter towards the outlet, the inner core portion being formed of a high stength, corrosion resistant, thermally conductive metal;
(b) an electrically insulated helical heating element having a plurality of spaced coils encircling the inner core portion and terminal means adapted to receive electric power from an external source;
(c) an elongated conductive portion cast on the inner core portion and the heating element to be bonded to them along their lengths, the conductive portion being formed of a metal having a high thermal conductivity;
(d) a spiral blade member extending in the central runner passage from the inlet to the outlet, the spiral blade member being attached along its edges to the inner surface of the inner core portion, the spiral blade member being formed of corrosion resistant material and gradually decreasing in pitch and thickness adjacent the outlet;
(e) an elongated outer sleeve portion formed of a corrosion resistant metal extending around the conductive portion; and (f) retaining means adapted to retain the nozzle bushing against rotation.
(a) a hollow elongated inner core portion having an inner surface defining a central runner passage extending longitudinally therethrough from an inlet to an outlet at opposite ends thereof, the central runner passage being generally cylindrical with a tapered portion which gradually decreases in diameter towards the outlet, the inner core portion being formed of a high stength, corrosion resistant, thermally conductive metal;
(b) an electrically insulated helical heating element having a plurality of spaced coils encircling the inner core portion and terminal means adapted to receive electric power from an external source;
(c) an elongated conductive portion cast on the inner core portion and the heating element to be bonded to them along their lengths, the conductive portion being formed of a metal having a high thermal conductivity;
(d) a spiral blade member extending in the central runner passage from the inlet to the outlet, the spiral blade member being attached along its edges to the inner surface of the inner core portion, the spiral blade member being formed of corrosion resistant material and gradually decreasing in pitch and thickness adjacent the outlet;
(e) an elongated outer sleeve portion formed of a corrosion resistant metal extending around the conductive portion; and (f) retaining means adapted to retain the nozzle bushing against rotation.
12. An injection molding nozzle bushing comprising:
(a) a hollow elongated body having an inner surface defining a generally cylindrical central runner passage extending longitudinally therethrough from an inlet to an outlet at opposite ends thereof;
(b) elongated heating means adapted to heat the elongated body; and (c) a spiral blade member formed of a corrosion resistant material extending in the central runner passage from the inlet to the outlet, the spiral blade member being brazed along its edges to the inner surface of the elongated body.
(a) a hollow elongated body having an inner surface defining a generally cylindrical central runner passage extending longitudinally therethrough from an inlet to an outlet at opposite ends thereof;
(b) elongated heating means adapted to heat the elongated body; and (c) a spiral blade member formed of a corrosion resistant material extending in the central runner passage from the inlet to the outlet, the spiral blade member being brazed along its edges to the inner surface of the elongated body.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000370734A CA1165525A (en) | 1981-02-12 | 1981-02-12 | Heated nozzle bushing with fixed spiral blade |
| DE19823201710 DE3201710A1 (en) | 1981-02-12 | 1982-01-21 | Sprue bush for injection-moulding apparatus |
| JP1831882A JPS57152928A (en) | 1981-02-12 | 1982-02-09 | Nozzle bush for injection molding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000370734A CA1165525A (en) | 1981-02-12 | 1981-02-12 | Heated nozzle bushing with fixed spiral blade |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1165525A true CA1165525A (en) | 1984-04-17 |
Family
ID=4119174
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000370734A Expired CA1165525A (en) | 1981-02-12 | 1981-02-12 | Heated nozzle bushing with fixed spiral blade |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS57152928A (en) |
| CA (1) | CA1165525A (en) |
| DE (1) | DE3201710A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4579520A (en) * | 1984-02-17 | 1986-04-01 | Gellert Jobst U | Injection molding valve gated system |
| US5206040A (en) * | 1991-12-11 | 1993-04-27 | Gellert Jobst U | Injection molding sealing collar with a central hot tip shaft |
| US7270538B2 (en) | 2002-10-02 | 2007-09-18 | Mold-Masters Limited | Mixing device |
| US7320589B2 (en) | 2003-02-26 | 2008-01-22 | Mold-Masters (2007) Limited | Hot runner manifold plug for rheological balance in hot runner injection molding |
| US7614872B2 (en) | 2005-10-04 | 2009-11-10 | Mold-Masters (2007) Limited | Melt redistribution element for an injection molding apparatus |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3425660A1 (en) * | 1984-07-12 | 1986-01-23 | Incoe Exp. Inc. Deutschland, 6072 Dreieich | NOZZLE FOR PLASTIC SPRAYING MACHINES |
| EP0293756A3 (en) * | 1987-06-01 | 1989-12-06 | Husky Injection Molding Systems Ltd. | Method of processing molten plastic materials |
| EP0791448A3 (en) * | 1996-02-26 | 1999-05-12 | HERBST, Richard | Method and apparatus for injection moulding of plastic articles |
| US5783234A (en) * | 1996-07-25 | 1998-07-21 | Husky Injection Molding Systems Ltd. | Hot runner valve gate for eliminating unidirectional molecular orientation and weld lines from solidified resin used for forming molded articles |
| NL1010868C2 (en) * | 1998-12-22 | 2000-06-27 | Axxicon Moulds Eindhoven Bv | An injection mold for disc-like objects with central holes, e.g. compact discs |
| ES2245093T3 (en) * | 1998-03-13 | 2005-12-16 | Axxicon Moulds Eindhoven B.V. | INJECTION MOLD FOR PLASTIC OBJECTS IN THE FORM OF A DISC AND MOLDING UNIT BY MULTIPLE INJECTION. |
| US6440350B1 (en) | 1999-03-18 | 2002-08-27 | Mold-Masters Limited | Apparatus and method for multi-layer injection molding |
| US6655945B1 (en) | 1999-03-18 | 2003-12-02 | Mold Masters Limited | Apparatus and method for multi-layer injection molding |
| US6398537B2 (en) | 1999-04-02 | 2002-06-04 | Mold-Masters Limited | Shuttle system for an apparatus for injection molding |
| US6196826B1 (en) | 1999-05-28 | 2001-03-06 | Mold-Masters Limited | Seepage system for an injection molding apparatus |
| US6089468A (en) * | 1999-11-08 | 2000-07-18 | Husky Injection Molding Systems Ltd. | Nozzle tip with weld line eliminator |
| DE10212234A1 (en) * | 2002-03-19 | 2003-10-09 | Junker Gmbh O | Device for uniformly loading a flat surface of a workpiece with a heated gas |
-
1981
- 1981-02-12 CA CA000370734A patent/CA1165525A/en not_active Expired
-
1982
- 1982-01-21 DE DE19823201710 patent/DE3201710A1/en not_active Withdrawn
- 1982-02-09 JP JP1831882A patent/JPS57152928A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4579520A (en) * | 1984-02-17 | 1986-04-01 | Gellert Jobst U | Injection molding valve gated system |
| US5206040A (en) * | 1991-12-11 | 1993-04-27 | Gellert Jobst U | Injection molding sealing collar with a central hot tip shaft |
| US7270538B2 (en) | 2002-10-02 | 2007-09-18 | Mold-Masters Limited | Mixing device |
| US7320589B2 (en) | 2003-02-26 | 2008-01-22 | Mold-Masters (2007) Limited | Hot runner manifold plug for rheological balance in hot runner injection molding |
| US7614872B2 (en) | 2005-10-04 | 2009-11-10 | Mold-Masters (2007) Limited | Melt redistribution element for an injection molding apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3201710A1 (en) | 1982-08-26 |
| JPS57152928A (en) | 1982-09-21 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |