WO2013043307A1

WO2013043307A1 - Mold-tool system including component having, at least in part, anodized aluminum material coupled to electrically-resistive heating element

Info

Publication number: WO2013043307A1
Application number: PCT/US2012/052233
Authority: WO
Inventors: Brian Esser
Original assignee: Husky Injection Molding Systems Ltd.
Priority date: 2011-09-20
Filing date: 2012-08-24
Publication date: 2013-03-28

Abstract

A mold-tool system (100), comprising: an electrically-resistive heating element (102), and a component (104) having, at least in part, an anodized aluminum material coupled to the electrically-resistive heating element (102).

Description

MOLD-TOOL SYSTEM INCLUDING COMPONENT HAVING, AT LEAST IN PART, ANODIZED ALUMINUM MATERIAL COUPLED TO ELECTRICALLY-RESISTIVE HEATING

ELEMENT TECHNICAL FIELD

Aspects generally relate to (and not limited to) mold-tool systems including (and not limited to) molding systems.

BACKGROUND

United States Patent Publication Number 2002/0054932 discloses a heater element brazed onto the nozzle housing and then embedded in multiple layers of plasma-sprayed stainless steel and alumina oxide. To avoid cracking of the ceramic layers caused by excessive thickness and the differing thermal properties of the ceramic and the stainless steel, alternating thin layers of stainless steel and alumina oxide. The heating element is a nickel- chrome resistance wire extending centrally through a refractory powder electrical insulating material, such as magnesium oxide, inside a steel casing. The heating element is integrally cast in a nickel alloy by a first brazing step in a vacuum furnace, which causes the nickel alloy to flow by capillary action into the spaces around the heater element to metallurgically bond the steel casing of the element to the nozzle body. This bonding produces very efficient and uniform heat transfer from the element to the nozzle body. Nozzles with this type of electrical heaters, however, are often too big to be used in small pitch gating due to the size of the insulated heater required. These heaters are also generally expensive to make because of complex machining required. Also, the manufacturing methods to make these nozzle heaters are complex and therefore production is time consuming.

United States Patent Number 6394784 discloses an injection molding nozzle wherein said second insulating layer is composed of a material chosen from the group of aluminum oxide, magnesium oxide, mica, polyimide, graphite, alumina, alumina-silica, tetragonal zirconia polycrystals (TZP), partially stabilised zirconia (PSZ), fully stabilised zirconia (FSZ), transformation toughened ceramics (TTC), zirconia toughened alumina (ZTA), transformation toughened zirconia (TTZ), zirconium silicate and silica.

United States Patent Publication Number 4621251 discloses an electric resistance heater assembly. The ceramic is selected from the group consisting of alumina, beryllia, titania, steatite, forsterite, cordierite, zirconium silicates, aluminum silicates, and lithia. The ceramic is alumina.

United States Patent Publication Number 4620086 discloses resistance heating wire coated with a sublayer of magnesium zirconate followed by an outer layer of aluminum oxide; each layer being in the range of 0.001 to 0.010 inches thick.

SUMMARY

The inventors have researched a problem associated with known molding systems that inadvertently manufacture bad-quality molded articles or parts. After much study, the inventors believe they have arrived at an understanding of the problem and its solution, which are stated below.

Current heater construction techniques utilize various means to package nichrome based resistive heating elements. These include various means of packaging cable heater elements (welded to support tubes, pressed into brass grooves, etc.), swaged (compressed) constructions wound on an insulative bobbin, elements brazed to the hot runner nozzle, etc. The problem with these methods are numerous. Cable elements pressed into a groove (either directly into the nozzle or as a separate component) are limited in watt density (the grooves can only be so close together) and require complex groove machining. Highly compacted wound constructions require such high compaction for reliable heater operation that if built directly onto a hot runner nozzle deformation of the nozzle is likely and would require extra machining. In addition, these wound construction techniques require relatively complex insulator bobbin geometries. These wound construction configurations, however, do have advantages over packaged cable elements in that the watt densities per unit area can be higher due to the ability to wrap the nichrome wire very close together, as well as the ability to have a very long wire (which allows for a larger cross section for a given overall wattage, increasing the durability and reliability of the heater assembly). Other consideration are heaters directly applied to the nozzle. These have included in the past plasma based heating elements and again cable heating elements installed in a groove and/or brazed directly to the nozzle. These types of installations offer benefits such as improved consistency of heat transfer to the object being heated, but also suffer from issues such as complexity in manufacturing. To resolve, at least in part, some of the problems identified above, according to one aspect, there is provided a mold-tool system (100), comprising: an electrically-resistive heating element (102), and a component (104) having, at least in part, an anodized aluminum material coupled to the electrically-resistive heating element (102).

Other aspects and features of the non-limiting embodiments will now become apparent to those skilled in the art upon review of the following detailed description of the non-limiting embodiments with the accompanying drawings. DETAILED DESCRIPTION OF THE DRAWINGS

The non-limiting embodiments will be more fully appreciated by reference to the following detailed description of the non-limiting embodiments when taken in conjunction with the accompanying drawings, in which: FIGS. 1 , 2A, 2B, 3A, 3B, 4 depict example schematic representations of a mold-tool system (100).

The drawings are not necessarily to scale and may be illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details not necessary for an understanding of the embodiments (and/or details that render other details difficult to perceive) may have been omitted.

DETAILED DESCRIPTION OF THE NON-LIMITING EMBODIMENT(S)

FIGS. 1 , 2A, 2B, 3A, 3B, 4 depict example schematic representations of a mold-tool system (100). It will be appreciated that the examples depicted in the FIGS, may be combined in any suitable permutation and combination. It will be appreciated that for the case of manufacturing original equipment: (i) a molding system (900) may have, at least in part, the mold-tool system (100), (ii) a runner system (916) may have, at least in part, the mold-tool system (100), and (iii) a mold assembly (918) may have, at least in part, the mold-tool system (100) of any preceding claim. It will be appreciated that for the case of retrofitting existing, the mold-tool system (100) may be sold or provided separately from the molding system (900), the runner system (916), and/or the mold assembly (918). In addition, the mold-tool system (100), the molding system (900), the runner system (916), and/or the mold assembly (918) 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 reference books (for example): (i) "Injection Molding Handbook' authored by OSSWALD/TURNG/G RAMAN N (ISBN: 3-446-21669-2), (ii) "Injection Molding Handbook' authored by ROSATO AND ROSATO (ISBN: 0-412- 99381 -3), (iii) "Injection Molding Systems" 3^rd Edition authored by JOHANNABER (ISBN 3- 446-17733-7) and/or (iv) "Runner and Gating Design Handbook' authored by BEAUMONT (ISBN 1 -446-22672-9). It will be appreciated that for the purposes of this document, the phrase "includes (but is not limited to)" is equivalent to the word "comprising." The word "comprising" is a transitional phrase or word that links the preamble of a patent claim to the specific elements set forth in the claim that define what the invention itself actually is. The transitional phrase acts as a limitation on the claim, indicating whether a similar device, method, or composition infringes the patent if the accused device (etc) contains more or fewer elements than the claim in the patent. The word "comprising" is to be treated as an open transition, which is the broadest form of transition, as it does not limit the preamble to whatever elements are identified in the claim.

Referring now to FIG. 1 , here is depicted a schematic representation of the molding system (900) having the mold-tool system (100). The molding system (900) may also be called an injection-molding system for example. According to the example depicted in FIG. 1 , the molding system (900) includes (and is not limited to): (i) an extruder assembly (902), (ii) a clamp assembly (904), (iii) a runner system (916), and/or (iv) a mold assembly (918). By way of example, the extruder assembly (902) is configured, to prepare, in use, a heated, flowable resin, and is also configured to inject or to move the resin from the extruder assembly (902) toward the runner system (916). Other names for the extruder assembly (902) may include injection unit, melt-preparation assembly, etc. By way of example, the clamp assembly (904) includes (and is not limited to): (i) a stationary platen (906), (ii) a movable platen (908), (iii) a rod assembly (910), (iv) a clamping assembly (912), and/or (v) a lock assembly (914). The stationary platen (906) does not move; that is, the stationary platen (906) may be fixedly positioned relative to the ground or floor. The movable platen (908) is configured to be movable relative to the stationary platen (906). A platen-moving mechanism (not depicted but known) is connected to the movable platen (908), and the platen-moving mechanism is configured to move, in use, the movable platen (908). The rod assembly (910) extends between the movable platen (908) and the stationary platen (906). The rod assembly (910) may have, by way of example, four rod structures positioned at the corners of the respective stationary platen (906) and the movable platen (908). The rod assembly (910) is configured to guide movement of the movable platen (908) relative to the stationary platen (906). A clamping assembly (912) is connected to the rod assembly (910). The stationary platen (906) supports the position of the clamping assembly (912). The lock assembly (914) is connected to the rod assembly (910), or may alternatively be connected to the movable platen (908). The lock assembly (914) is configured to selectively lock and unlock the rod assembly (910) relative to the movable platen (908). By way of example, the runner system (916) is attached to, or is supported by, the stationary platen (906). The runner system (916) includes (and is not limited to) a mold-tool system (100). The definition of the mold-tool system (100) is as follows: a system that may be positioned and/or may be used in a platen envelope (901 ) defined by, in part, an outer perimeter of the stationary platen (906) and the movable platen (908) of the molding system (900) (as depicted in FIG. 1 ). The molding system (900) may include (and is not limited to) the mold-tool system (100). The runner system (916) is configured to receive the resin from the extruder assembly (902). By way of example, the mold assembly (918) includes (and is not limited to): (i) a mold-cavity assembly (920), and (ii) a mold-core assembly (922) that is movable relative to the mold-cavity assembly (920). The mold-core assembly (922) is attached to or supported by the movable platen (908). The mold-cavity assembly (920) is attached to or supported by the runner system (916), so that the mold-core assembly (922) faces the mold-cavity assembly (920). The runner system (916) is configured to distribute the resin from the extruder assembly (902) to the mold assembly (918).

In operation, the movable platen (908) is moved toward the stationary platen (906) so that the mold-cavity assembly (920) is closed against the mold-core assembly (922), so that the mold assembly (918) may define a mold cavity configured to receive the resin from the runner system (916). The lock assembly (914) is engaged so as to lock the position of the movable platen (908) so that the movable platen (908) no longer moves relative to the stationary platen (906). The clamping assembly (912) is then engaged to apply a camping pressure, in use, to the rod assembly (910), so that the clamping pressure then may be transferred to the mold assembly (918). The extruder assembly (902) pushes or injects, in use, the resin to the runner system (916), which then the runner system (916) distributes the resin to the mold cavity structure defined by the mold assembly (918). Once the resin in the mold assembly (918) is solidified, the clamping assembly (912) is deactivated so as to remove the clamping force from the mold assembly (918), and then the lock assembly (914) is deactivated to permit movement of the movable platen (908) away from the stationary platen (906), and then a molded article may be removed from the mold assembly (918). The definition of the mold-tool system (100) is as follows: a system that may be positioned and/or may be used in an envelope defined by the movable platen (908) and the stationary platen (906) of the molding system (200).

Referring generally to FIGS. 2A, 2B, 3A, 3B, 4, the mold-tool system (100) includes (and is not limited to) a combination of: (i) an electrically-resistive heating element (102), and (ii) a component (104) having, at least in part, an anodized aluminum material coupled to the electrically-resistive heating element (102). The anodized aluminum material may contact the electrically-resistive heating element (102). According to an option, the anodized aluminum material has, at least in part, a type III anodized aluminum material. According to another option, the electrically-resistive heating element (102) has, at least in part, a nickel- chromium material. According to a first variation, which is explicitly depicted by FIG. 2A, the mold-tool system (100) is further arranged (and is not limited to) such that the electrically- resistive heating element (102) is wound (or wrapped), at least in part, around the component (104). FIG. 2A is a cross-sectional view of the mold-tool system (100) taken along a longitudinal axis that extends through the mold-tool system (100). FIGS. 2B, 3A, 3B, 4 are cross-sectional views as well. Referring now to FIG. 2B, according to a second variation, the mold-tool system (100) is further arranged such that the mold-tool system (100) further includes (and is not limited to): a melt-conveying body (106) that contacts, at least in part, the component (104).

According to a third variation, the mold-tool system (100) is further arranged such that the component (104) is slipped over, at least in part, the melt-conveying body (106).

According to an alternative to the third variation, the mold-tool system (100) is further arranged such that the component (104) is integrated, at least in part, with the melt- conveying body (106).

According to a fourth variation, the mold-tool system (100) is further arranged such that the component (104) includes, at least in part, a sleeve configured to slip over, at least in part, the melt-conveying body (106). Referring now to FIG. 3A, according to a fifth variation, the mold-tool system (100) is further arranged such that the melt-conveying body (106) includes, at least in part, a runner system

(916) . Referring now to FIG. 3B, according to a sixth variation, the mold-tool system (100) is further arranged such that the melt-conveying body (106) includes, at least in part, a nozzle assembly (917). The nozzle assembly (917) may have, at least in part, a nozzle tip (915).

Referring now to FIG. 4, according to a seventh variation, the mold-tool system (100) is further arranged such that the melt-conveying body (106) includes, at least in part, a mold assembly (918).

According to an example, a component of the mold-tool system (100) includes a type III anodized aluminum tube shaped as a mandrel for wrapping the nichrome wire based heating element. This type II I anodized aluminum provides the electrical dielectric insulation required to be able to wrap a nichrome wire heating element on the type III anodized aluminum. This allows for a high watt density heater with improved inherent thermal conductivity. The type III anodized aluminum sleeve need be just thick enough to be compatible with the anodizing and construction process, but may have increased thickness if desired to improve the spreading of heat along the length of, for example, the nozzle assembly (917). The construction may be used to create the mold-tool system (100) that is of a stand alone slip-on style, which may be called a heater assembly, but also allows the mold-tool system (100) to be built directly onto the nozzle assembly (917) providing consistent heat transfer, for example, to the nozzle assembly (917).

The mold-tool system (100) solves, at least in part, some of the issues with existing or known the heater construction methods mentioned above. For example, the mold-tool system (100) allows for a wound heater construction to be made more simply than is currently possible, and further allows, for example, for the type III anodized aluminum sleeve or tube to be applied directly to a nozzle assembly (917) if so desired, so that this arrangement eliminates the need for swaging the material and/or the nozzle assembly

(917) , requires less complex constituent components, and should be more economical and less complex to manufacture. One component of the mold-tool system (100) is the utilization of an aluminum sleeve as shaped as a mandrel on which the nichrome wire is wound upon. The aluminum sleeve is finished with a Type III Hardcoat Anodize finish, which has a dielectric strength up to 1500 VAC (volts alternating current) at coating thicknesses of only 50 microns. Type III anodizing is an acid based surface finish that both penetrates the surface and builds up upon it, forming a strong, stable oxide layer that is fundamentally integrated to the base material. A Type II I anodized tube allows for a one component, self supporting, thermally conductive, cut-to length, low cost foundation for the heater construction. After winding, the coil can be top coated using various methods including but not limited to thermal spray, spray-on ceramic, brush-on ceramic, dipping, etc. The top coating insulated the resistive wire from the surrounding environment and provides a conductive path for heat transfer out of the wire element. After top coating, lead wires are attached and a secondary protective outer covering may be applied if necessary. By press fitting or otherwise securing such a tube directly to a nozzle, an outer surface with high dielectric strength is created on the outer diameter of the nozzle assembly (917) which a resistive heating wire can be directly wound upon. This allows the mold-tool system (100) to be built into the nozzle assembly (917), reducing the variation caused by the fit of the mold-tool system (100) over the nozzle assembly (917) and nozzle components. Also, the use of highly thermally conductive aluminum may reduce temperature variations along the length of the nozzle assembly (917) by moving heat from warmer areas to colder ones of the nozzle assembly (917).

ADDITIONAL DESCRIPTION

The following clauses are offered as further description of the examples of the mold-tool system (100): Clause (1 ): a mold-tool system (100), comprising: an electrically-resistive heating element (102); and a component (104) having, at least in part, an anodized aluminum material coupled to electrically-resistive heating element (102). Clause (2): the mold-tool system (100) of any clause mentioned in this paragraph, wherein: the anodized aluminum material has, at least in part, a type II I anodized aluminum material. Clause (3): the mold-tool system (100) any clause mentioned in this paragraph, wherein: the electrically-resistive heating element (102) has, at least in part, a nickel-chromium material. Clause (4): the mold-tool system (100) any clause mentioned in this paragraph, wherein: the electrically-resistive heating element (102) is wound, at least in part, around the component (104). Clause (5): the mold-tool system (100) any clause mentioned in this paragraph, further comprising: a melt-conveying body (106) contacting, at least in part, the component (104). Clause (6): the mold-tool system (100) any clause mentioned in this paragraph, wherein: the component (104) is slipped over, at least in part, the melt- conveying body (106). Clause (7): the mold-tool system (100) any clause mentioned in this paragraph, wherein: the component (104) is integrated, at least in part, with the melt- conveying body (106). Clause (8): the mold-tool system (100) any clause mentioned in this paragraph, wherein: the component (104) includes, at least in part, a sleeve configured to slip over, at least in part, the melt-conveying body (106). Clause (9): the mold-tool system (100) any clause mentioned in this paragraph, wherein: the melt-conveying body (106) includes, at least in part, a runner system (916). Clause (10): the mold-tool system (100) any clause mentioned in this paragraph, wherein: the melt-conveying body (106) includes, at least in part, a nozzle assembly (917). Clause (11 ): the mold-tool system (100) any clause mentioned in this paragraph, wherein: the melt-conveying body (106) includes, at least in part, a mold assembly (918).

It will be appreciated that the assemblies and modules described above may be connected with each other as may be required to perform desired functions and tasks that are within the scope of persons of skill in the art to make such combinations and permutations without having to describe each and every one of them in explicit terms. There is no particular assembly, components, or software code that is superior to any of the equivalents available to the art. There is no particular mode of practicing the inventions and/or examples of the invention that is superior to others, so long as the functions may be performed. It is believed that all the crucial aspects of the invention have been provided in this document. It is understood that the scope of the present invention is limited to the scope provided by the independent claim(s), and it is also understood that the scope of the present invention is not limited to: (i) the dependent claims, (ii) the detailed description of the non-limiting embodiments, (iii) the summary, (iv) the abstract, and/or (v) description provided outside of this document (that is, outside of the instant application as filed, as prosecuted, and/or as granted). It is understood, for the purposes of this document, the phrase "includes (and is not limited to)" is equivalent to the word "comprising." It is noted that the foregoing has outlined the non-limiting embodiments (examples). The description is made for particular non-limiting embodiments (examples). It is understood that the non-limiting embodiments are merely illustrative as examples.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A mold-tool system (100), comprising:

an electrically-resistive heating element (102); and

a component (104) having, at least in part, an anodized aluminum material coupled to the electrically-resistive heating element (102).

2. The mold-tool system (100) of claim 1 , wherein:

the anodized aluminum material has, at least in part, a type III anodized aluminum material.

3. The mold-tool system (100) of any preceding claim, wherein:

the electrically-resistive heating element (102) has, at least in part, a nickel- chromium material.

4. The mold-tool system (100) of any preceding claim, wherein:

the electrically-resistive heating element (102) is wound, at least in part, around the component (104).

5. The mold-tool system (100) of any preceding claim, further comprising:

a melt-conveying body (106) contacting, at least in part, the component (104).

6. The mold-tool system (100) of any preceding claim, wherein:

the component (104) is slipped over, at least in part, the melt-conveying body

(106).

7. The mold-tool system (100) of any preceding claim, wherein:

the component (104) is integrated, at least in part, with the melt-conveying body (106).

8. The mold-tool system (100) of any preceding claim, wherein:

the component (104) includes, at least in part, a sleeve configured to slip over, at least in part, the melt-conveying body (106).

9. The mold-tool system (100) of any preceding claim, wherein:

the melt-conveying body (106) includes, at least in part, a runner system

(916) .

10. The mold-tool system (100) of any preceding claim, wherein:

the melt-conveying body (106) includes, at least in part, a nozzle assembly

(917) .

11 . The mold-tool system (100) of any preceding claim, wherein:

the melt-conveying body (106) includes, at least in part, a mold assembly

(918) .

12. A molding system (900) having, at least in part, the mold-tool system (100) of any preceding claim.

13. A runner system (916) having, at least in part, the mold-tool system (100) of any preceding claim.

14. A mold assembly (918) having, at least in part, the mold-tool system (100) of any preceding claim.