WO2014085008A1

WO2014085008A1 - Molding material distribution device

Info

Publication number: WO2014085008A1
Application number: PCT/US2013/067163
Authority: WO
Inventors: Brian Esser
Original assignee: Husky Injection Molding Systems Ltd.
Priority date: 2012-11-27
Filing date: 2013-11-13
Publication date: 2014-06-05

Abstract

A molding material distribution device (200) for a molding system. The molding material distribution device (200) includes a nozzle (110) having a nozzle body (120). The nozzle body (120) has an upstream end (126), a central portion (128), and a downstream end (124). The nozzle body (120) defines a nozzle flow channel (122) being configured to convey, in use, a molding material. The nozzle (110) also includes a heat distributor layer (130). The heat distributor layer (130) is disposed on an outer surface (132) of the nozzle body (120). The nozzle (110) further includes a heater (140). The heater (140) is disposed on an outer surface (134) of the heat distributor layer (130). The heat distributor layer (130) is configured to distribute, in use, heat from the heater (140) along the heat distributor layer (130).

Description

MOLDING MATERIAL DISTRIBUTION DEVICE

TECHNICAL FIELD Non-limiting embodiments disclosed herein generally relate to molding material distribution devices for use in molding systems.

BACKGROUND Molding is a process by virtue of which a molded article can be formed from molding material by using a molding system. Various molded articles can be formed by using a molding process, such as an injection molding process. One example of a molded article that can be formed, for example, from polyethylene terephthalate (PET material) is a preform suitable for subsequent blow molding into a final shaped container.

A typical molding system includes inter alia an injection unit, a clamp assembly and a mold assembly. One example of an injection unit is a reciprocating screw type injection unit. Within the reciprocating screw type injection unit, molding material (such as PET or the like) is fed through a hopper, which in turn feeds an inlet end of the injection unit. A screw is encapsulated in a barrel, which is heated by a barrel heater. Helical flights of the screw convey the molding material along an operational axis thereof. Typically, a root diameter of the screw is progressively increased along the operational axis thereof, in a direction away from the inlet end.

As the molding material is conveyed along the screw, it is sheared between the flights of the screw, the screw root, and the inner surface of the barrel. The molding material is also subjected to some heat emitted by the barrel heater and conducted through the barrel. When a desired amount of the molding material is accumulated in a space at a discharge end of the screw (which is an opposite extreme of the screw vis-a-vis an inlet end), the screw stops its rotation. The screw is then forced forward (in a direction away from the inlet end thereof), forcing the desired amount of the molding material into one or more molding cavities. The screw may perform two functions in the screw type injection unit, namely plasticizing of molding material and injecting the molding material into a mold cavity.

The molding material may enter the mold cavity through a gate via a molding material distribution device, e.g. a hot runner. A molding material distribution device is typically comprised of several components, including a sprue to receive molding material from the injection unit, a manifold assembly to distribute the molding material to several ports, and a plurality of nozzles to transfer the molding material from the ports to the receiving mold cavity defined by the mold assembly. Usually, molding material distribution devices and mold assemblies are treated as tools that may be sold separately (or together) from molding systems.

SUMMARY

In accordance with an aspect disclosed herein, there is provided a molding material distribution device including a nozzle. The nozzle includes a nozzle body. The nozzle body has an upstream end, a central portion, and a downstream end. The nozzle body defines a flow channel being configured to convey, in use, a molding material. The nozzle also includes a heat distributor layer. The heat distributor layer is disposed on an outer surface of the nozzle body. The nozzle further includes a heater. The heater is disposed on an outer surface of the heat distributor layer. The heater is located only adjacent the downstream end. The heat distributor layer is configured to distribute, in use, heat from the heater along the heat distributor layer.

These and other aspects and features of non-limiting embodiments will now become apparent to those skilled in the art upon review of the following description of specific non-limiting embodiments in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

The non-limiting embodiments will be more fully appreciated by reference to the accompanying drawings, in which:

FIG. 1 depicts a diagrammatic representation of an injection molding system according to a non- limiting embodiment.

FIG. 2 depicts a partial cross-sectional, side view of a diagrammatic representation of a molding material distribution system according to a first non- limiting embodiment.

FIG. 3 depicts a cross-sectional, side view of a diagrammatic representation of a molding material distribution system according to a second non-limiting embodiment. The drawings are not necessarily to scale and may be 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 NON-LIMITING EMBODIMENT(S

Reference will now be made in detail to various non-limiting embodiment(s) of a nozzle for a molding system. It should be understood that other non-limiting embodiment(s), modifications and equivalents will be evident to one of ordinary skill in the art in view of the non-limiting embodiment(s) disclosed herein and that these variants should be considered to be within scope of the appended claims.

Furthermore, it will be recognized by one of ordinary skill in the art that certain structural and operational details of the non-limiting embodiment(s) discussed hereafter may be modified or omitted (i.e. non-essential) altogether. In other instances, well known methods, procedures, and components have not been described in detail.

FIG. 1 is a diagrammatic representation of an injection molding system 900 in accordance with a non- limiting embodiment. Generally, the injection molding system 900 includes (and is not limited to): (i) an injection unit 902, (ii) a clamp assembly 904, (iii) a mold assembly 906, and (iv) a molding material distribution device 100. The injection unit 902 includes: (i) a barrel 912, (ii) a hopper 914, (iii) a barrel heater 916, and (iv) a screw 918. The mold assembly 906 includes: (i) a movable mold portion 910, and (ii) a stationary mold portion 908. The movable mold portion 910 and the stationary mold portion 908 cooperate to define a mold cavity 920. The molding material distribution device 100 is configured to convey, in use, a molding material from the injection unit 902 to the mold assembly 906.

FIG. 2 is a diagrammatic representation of a molding material distribution device 200 in accordance with a first non-limiting embodiment. The molding material distribution device 200 includes (and is not limited to): (i) a nozzle 210 and (ii) a manifold assembly 160 associated with the nozzle 210. The nozzle 210 includes a nozzle body 120. The nozzle body 120 has a downstream end 124, an upstream end 126, and a central portion 128. The nozzle 210, as depicted, further includes a nozzle tip 150. The nozzle tip 150 is fluidly connected to the downstream end 124 of the nozzle body 120. The nozzle body 120 defines a nozzle flow channel 122 configured to convey, in use, a molding material. The manifold assembly 160 defines a manifold flow channel 162 configured to convey, in use, the molding material. The upstream end 126 of the nozzle body 120 is configured to connect, fluidly, with the manifold assembly 160 such that the nozzle flow channel 122 mates with the manifold flow channel 162.

The nozzle body 120 may be made from any suitable high strength material capable of withstanding the pressures and wear effects of the molding material being delivered to a mold assembly 906 (see FIG. 1). For example, the nozzle body 120 may be made from steel. The nozzle body 120 may have any suitable shape. For example, the nozzle body 120 may be cylindrical.

The nozzle 210 further includes a heat distributor layer 130 disposed on an outer surface 132 of the nozzle body 120. The heat distributor layer 130 at least partially surrounds the nozzle body 120. The heat distributor layer 130 may be in direct physical contact with the outer surface 132 of the nozzle body 120. The heat distributor layer 130 may be formed of any suitable conductive material that will conduct heat along the length of the heat distributor layer 130. For example, the heat distributor layer 130 may be formed from alloys or compositions including copper, brass, aluminum, copper alloy, aluminum alloy, and multi-material combinations such as diamond copper, diamond aluminum, etc.

The heat distributor layer 130 may be disposed on the outer surface 132 of the nozzle body 120 by any suitable method. For example, the heat distributor layer 130 may be pre formed as a hollow sleeve and subsequently attached to nozzle body 120, which may be attached using any suitable method. For example, a friction fit, screwing, welding, etc. The heat distributor layer 130 may also be applied by a thermal spraying technique (e.g. plasma spraying and the like). In a non-limiting embodiment, the hollow sleeve may have a continuous (i.e. uninterrupted) surface. In another a non- limiting embodiment, the surface of the hollow sleeve may be configured as a cage or a web. The heat distributor layer 130 may be disposed on the outer surface 132 of the nozzle body 120 by being manufactured integrally with the nozzle body 120 by any suitable method. For example, the heat distributor layer 130 may be manufactured integrally with the nozzle body 120 using a solid freeform fabrication process (SFF), also referred to as an additive manufacturing fabrication process. SFF is a collection of techniques for manufacturing solid objects by the sequential delivery of energy and/or material to specified points in space to produce that solid. SFF is sometimes referred to as rapid prototyping, rapid manufacturing, layered manufacturing, additive fabrication and free form manufacturing.

The nozzle 210 further includes a heater 140. The heater 140 is disposed on an outer surface 134 of the heat distributor layer 130. The heater 140 may be in direct physical contact with an outer surface 134 of the heat distributor layer 130. The heater 140 is located only adjacent the downstream end 124 of the nozzle body 120. The heat distributor layer 130 may be configured to distribute heat from the heater 140 along substantially an entire length of the nozzle body 120. The heat distributor layer 130 is configured to transmit, in use, heat received at least one of the upstream end 126 and at the downstream end 124 toward the central portion 128.

The heater 140 may be any suitable type of heater. For example, a heater based on a mineral insulated cable heating element, a coiled nichrome heating element, a film heater (plasma spray heater, thin film heater, and thick film heater, among others), a tungsten heater encased in aluminum nitride, etc.

The heater 140 may be disposed on the outer surface 134 of the heat distributor layer 130 using any suitable method. For example, heater 140 can be provided in the form of a hollow cylinder disposed on the heat distributor layer 130 with a friction fit, screwing, welding, etc. The heater 140 may also be disposed with various deposition means including but not limited to thermal spraying, physical vapor deposition, chemical vapor deposition, etc.

In operation, the heat distributor layer 130 acts to distribute heat sufficiently to provide uniform heating/a relatively constant temperature profile over the length of the nozzle body 120. The heat distributor layer 130 also creates in effect a thermal reservoir that can absorb heat from, as well as give heat to, molding material being conveyed through the nozzle flow channel 122.

FIG. 3 is a diagrammatic representation of a molding material distribution device 300 in accordance with second non-limiting embodiment. The molding material distribution device 300 includes (and is not limited to): (i) a nozzle 310 and (ii) a manifold assembly 160 associated with the nozzle 310. The molding material distribution device 300 is substantially similar the molding material distribution device 200 depicted in FIG. 2, other than the nozzle 310 further includes an insulative layer 270. The insulative layer 270 extends along the outer surface 134 of the heat distributor layer 130.

The insulative layer 270 may be a hollow sleeve of thermally insulative material, such as ceramic (e.g. aluminum oxide, zirconioa, etc.) or may be a hollow sleeve of a polymeric material such as polytetrafluoroethylene, silicone, polyamide, polyether ether ketone, etc. The insulative layer 270 may also be directly deposited on the heat distributor layer 130.

In a non-limiting embodiment (not shown), the insulative layer 270 may be a hollow sleeve of that is connected to the heat distributor layer 130 adjacent an upstream end (not separately numbered) and a downstream end (not separately numbered) thereof, such that a gap is provided between the heat distributor layer 130 and the insulative layer 270. In operation, the insulative layer 270 reduces heat losses. The insulative layer 270 also increases the thermal uniformity along a length of the nozzle flow channel 122 by making heat transfer along the length of the nozzle body 120 more efficient.

It is noted that the foregoing has outlined some of the more pertinent non-limiting embodiments. It will be clear to those skilled in the art that modifications to the disclosed non-embodiment(s) can be effected without departing from the spirit and scope thereof. As such, the described non-limiting embodiment(s) ought to be considered to be merely illustrative of some of the more prominent features and applications. Other beneficial results can be realized by applying the non-limiting embodiments in a different manner or modifying them in ways known to those familiar with the art. This includes the mixing and matching of features, elements and/or functions between various non- limiting embodiment(s) is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one embodiment may be incorporated into another embodiment as skill in the art would appreciate from this disclosure that features, elements and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless described otherwise, above. Although the description is made for particular arrangements and methods, the intent and concept thereof may be suitable and applicable to other arrangements and applications.

Claims

WHAT IS CLAIMED IS:

1. A molding material distribution device (200, 300), comprising:

a nozzle (210, 310) including:

a nozzle body (120) having an upstream end (126), a central portion (128), and a downstream end (124), the nozzle body defining a nozzle flow channel (122) configured to convey, in use, a molding material;

a heat distributor layer (130) disposed on an outer surface (132) of the nozzle body (120); and

a heater (140) disposed on an outer surface (134) of the heat distributor layer (130) and located only adjacent the downstream end (124), wherein the heat distributor layer (130) is configured to distribute, in use, heat from the heater (140) along the heat distributor layer (130).

2. The molding material distribution device (200, 300) of claim 1, wherein:

the heat distributor layer (130) formed of a conductive material.

3. The molding material distribution device (200, 300) of claim 2, wherein:

the conductive material is one of copper, brass, bronze, aluminum, copper alloy, aluminum alloy, aluminum nitride, diamond, diamond copper and diamond aluminum.

4. The molding material distribution device (200, 300) of claim 1, wherein the nozzle (210, 310) further includes:

a nozzle tip (150) connected, fluidly, to the downstream end (124) of the nozzle body (120).

5. The molding material distribution device (200, 300) of claim 1, wherein:

the heat distributor layer (130) is in direct contact with the outer surface (132) of the nozzle body (120).

6. The molding material distribution device (200, 300) of claim 1, wherein:

the heater (140) is in direct physical contact with the outer surface (134) of the heat distributor layer (130).

7. The molding material distribution device (200, 300) of claim 1, further comprising: a manifold assembly (160) defining a manifold flow channel (162) configured to convey, in use, the molding material, wherein the upstream end (126) of the nozzle body (120) is configured to connect, fluidly, with the manifold assembly (160) such that the nozzle flow channel (122) mates with the manifold flow channel (162).

The molding material distribution device (200, 300) of claim 7, wherein:

the heat distributor layer (130) is configured to distribute, in use, heat received at the upstream end (126) and at the downstream end (124) toward the central portion (128).

The molding material distribution device (200, 300) of claim 7, wherein:

the heat distributor layer (130) is in direct contact with the manifold assembly (160).

The molding material distribution device (200, 300) of claim 1, further comprising:

an insulative layer (270) extending along the outer surface (134) of the heat distributor layer (130).

11. An injection molding system (900), comprising:

the molding material distribution device (200, 300) of any one of claims 1-10.