Shut-off nozzle for injection molding

Abstract

A novel shut-off nozzle for injection molding systems is disclosed herein for producing and injecting foamed polymers to form products and other parts. The shut-off nozzle is designed to increase cell nucleation during the foaming process, increase the rate of pressure drop as the polymer is injected into the mold, and stop the die swell of the foamed polymer at the end of the injection cycle. The shut-off nozzle includes an angled shut-off needle, which significantly reduces the amount of waste per injection cycle, and a water-cooled circuit for rapidly cooling and solidifying the molten polymer remaining in the shut-off nozzle at the end of each injection cycle.

Description

Technical Field

[0001] This disclosure generally relates to a shut-off nozzle for injection molding processes. More specifically, this disclosure relates to a highly efficient shut-off nozzle for polymer foam injection molding to form components and parts with precise dimensions and flawless surfaces. Background Technology

[0002] Injection molding systems and processes are very useful in manufacturing plastic products and parts. A typical injection molding system includes an injection molding machine and a mold. An injection molding machine includes a barrel, a reciprocating screw at least partially located within the barrel, a heating element for heating the barrel, and a nozzle extending from the end of the barrel. The mold includes a cavity that is shaped to the desired product or part. The injection molding process begins by supplying a solid polymer source (e.g., polymer granules) to the reciprocating screw, which introduces the polymer into the barrel. Through the combination of shear stress applied by the reciprocating screw and heat applied to the barrel by the heating element, the polymer granules melt to form molten polymer that can flow through the barrel. The nozzle is placed near the mold opening, and the molten polymer flows into the mold cavity until the cavity is filled and the flow of the molten polymer stops. Once the cavity is filled, the mold is cooled until the polymer solidifies to form the desired product or part. The product or part is removed from the mold, and the process is repeated. Although the basic injection molding process may seem quite simple, the different properties of different polymers and the control of their viscosity and flow require precise methods and environmental parameters to create repeatable injection molding processes.

[0003] For example, if a particular polymer forms a high-viscosity molten polymer upon heating and shearing, this molten polymer can be injected into a mold using a simple straight-through nozzle without any specific resistance. Due to its high viscosity, the polymer tends not to continue flowing from the nozzle when the flow stops. However, if the polymer has a low viscosity in the molten state, the molten polymer may continue to flow and leak from the nozzle tip at the end of the injection process, when the system intends to stop the flow (often referred to as "drooling"). This drooling causes undesirable flash and requires frequent cleaning by the operator, which slows down the injection molding process and leads to inefficiency. These problems are particularly severe when products or parts are molded from polymer foam.

[0004] The use of polymer foam in injection molding increases process complexity. Compared to standard solid injection molding, foam injection molding is more sensitive to environmental parameters and presents challenges for flow control using existing shut-off nozzles. These existing shut-off nozzles have drawbacks and are not readily applicable to foam injection molding. In particular, existing nozzles pose significant challenges once the molten polymer is saturated with gas (i.e., foamed). First, when the molten polymer is saturated with gas introduced by the foaming agent, the polymer's melt flow index (MFI) is very high, causing severe drooling problems in the injection molding process. Furthermore, this gas-saturated molten polymer must be carefully controlled to produce more efficient nucleation and a higher pressure drop rate, which leads to greater expansion of the polymer entering the mold and provides a more uniform cell structure for the final product or part.

[0005] Existing shut-off nozzles for foaming polymers can cause excessive drooling and inconsistent final products and parts. Figure 1 illustrates such an existing shut-off nozzle 10. This shut-off nozzle 10 includes a shut-off mechanism 20, which is generally positioned perpendicular to the flow direction of the molten polymer through the system. In the example of Figure 1, the shut-off mechanism 20 includes a pin (also called a needle) 30, which is selectively actuated to prevent polymer from flowing through the flow channel 40 of the shut-off nozzle 10. The pin 30 is positioned in a channel 50 that intersects the flow channel 40 at a right angle. As shown in the enlarged image of Figure 1A, the diameter of the flow channel 40 is not uniform near its intersection with the channel 50. As the polymer flows through the flow channel 40, the diameter of the flow channel 40 first decreases twice in stages as the polymer approaches the channel 50, thus reducing the diameter of the flow channel 40 twice. Subsequently, as the polymer moves away from the channel 50, the diameter increases twice in stages, thus increasing the diameter of the flow channel 40 twice. These variations in the diameter of the flow channel 40 are designed to reduce the diameter at the intersection of the pin 30 and the flow channel 40, making it easier for the pin 30 to prevent the molten polymer from flowing through the flow channel 40. However, the reduction in diameter of the flow channel 40 before its intersection with channel 50 and the expansion in diameter after its intersection with channel 50 are extremely detrimental to the quality and quantity of foaming experienced by the molten polymer. These diameter changes lead to premature and inefficient cell nucleation and formation in the molten polymer, ultimately resulting in poor weight reduction of the molded part and inconsistent cell morphology.

[0006] Referring again to Figure 1, when pin 30 is in the retracted position, polymer can flow freely through the flow channel 40 of the shut-off nozzle 10, exit from the nozzle tip 60, and enter the waiting mold cavity. When pin 30 is actuated, pin 30 moves upward (relative to Figure 1), positioning itself in the flow channel 40 to stop polymer flow through it. In this prior art machine 10, the distance (D1) between the position where pin 30 of the shut-off mechanism 20 engages the flow channel 40 to stop polymer flow and the end of the nozzle tip 60 is large. This results in a large amount of molten polymer remaining between pin 30 and the end of nozzle tip 60. When the injection cycle ends, the mold is cooled to allow the molded part to solidify. However, the large amount of polymer remaining in the shut-off nozzle 10 often only partially solidifies between cycles. This makes it difficult to eject the remaining polymer and results in unwanted flash and excessive drooling, which unnecessarily affects the next molded part and often interrupts the injection molding process because the shut-off nozzle 10 needs to be cleaned.

[0007] This disclosure describes a novel shut-off nozzle for polymer foam injection molding that addresses the problems of existing shut-off nozzles, significantly enhancing control over the injection molding process and producing final molded products and parts of superior quality. Summary of the Invention

[0008] This paper discloses a novel shut-off nozzle for injection molding systems used to generate and inject foamed polymers to form products and other parts. The shut-off nozzle is designed to increase cell nucleation during the foaming process, increase the pressure drop rate as the polymer is injected into the mold, and prevent drooling of the foamed polymer at the end of the injection cycle. The shut-off nozzle includes a novel shut-off mechanism with angled shut-off pins that significantly reduces waste per injection cycle; and a novel nozzle tip with a fluid cooling circuit to rapidly cool and solidify any molten polymer remaining in the shut-off nozzle at the end of each injection cycle.

[0009] In one embodiment disclosed herein, the shut-off nozzle includes a body, a nozzle tip body extending from the body, a flow channel passing through the body and the nozzle tip body, a nozzle tip partially positioned within the nozzle tip body, and a shut-off mechanism. The shut-off mechanism includes a channel intersecting the flow channel at an angle and a pin positioned within the channel. The intersection of the channel and the flow channel is near the nozzle tip. The shut-off mechanism is arranged to move the pin between a retracted position and an actuated position, wherein when the pin is in the actuated position, the pin intersects the flow channel such that no material can flow through the intersection of the channel and the flow channel, and when the pin is in the retracted position, the pin does not intersect the flow channel, and material can flow through the intersection of the channel and the flow channel.

[0010] In another embodiment disclosed herein, the shut-off nozzle includes a body, a nozzle tip body extending from the body, a nozzle tip partially positioned within the nozzle tip body, and a flow channel passing through the body, the nozzle tip body, and the nozzle tip. The nozzle tip includes a cooling mechanism. The cooling mechanism includes a helical loop positioned around the flow channel passing through the nozzle tip and arranged to receive a flow of cooling fluid passing through the helical loop. As the cooling fluid flows through the helical loop, heat from the nozzle tip flow channel is transferred to the cooling fluid, causing any molten polymer in the nozzle tip flow channel to solidify. Furthermore, any molten polymer in the flow channel near the nozzle tip will also solidify as heat is transferred from the nozzle tip flow channel to the cooling fluid flowing through the helical loop. When the molten polymer in the flow channel solidifies, the solidified polymer can be ejected from the shut-off nozzle as a continuous whole. Attached Figure Description

[0011] In the accompanying drawings, the illustrated structures, together with the detailed description provided below, depict exemplary embodiments of the disclosed systems, methods, and apparatus. Where appropriate, similar elements are identified by the same or similar reference numerals. An element shown as a single component may be replaced by multiple components. An element shown as multiple components may be replaced by a single component. The drawings may not be drawn to scale. For illustrative purposes, the scale of some elements may be exaggerated.

[0012] Figure 1 schematically shows a cross-sectional view of a prior art shut-off nozzle.

[0013] Figure 1A is an enlarged view of the flow path of the prior art shut-off nozzle in Figure 1, showing the flow path near the shut-off nozzle.

[0014] Figure 2 is a photograph of an article formed using an injection molding machine with a conventional shut-off nozzle.

[0015] Figure 3 A perspective view of an exemplary embodiment of a shut-off nozzle for an injection molding machine is schematically shown.

[0016] Figure 4 schematically shown Figure 3 A perspective view of the shut-off nozzle, with the transparent portion revealing the internal mechanism.

[0017] Figure 5 schematically shown Figure 3 A side sectional view of the shut-off nozzle.

[0018] Figure 6 schematically shown Figure 3 Another cross-sectional view of the shut-off nozzle.

[0019] Figure 7 schematically shown Figure 3A side view of the shut-off nozzle, with the transparent portion showing the shut-off mechanism.

[0020] Figure 8 schematically shown Figure 7 The part marked in the middle.

[0021] Figure 9 schematically shown Figure 7 The part marked in the middle.

[0022] Figure 10 schematically shown Figure 3 A cross-sectional view of the engagement between the pin of the stop nozzle and the drive plate.

[0023] Figure 11 schematically shown Figure 3 Another view of the engagement between the pin of the stop nozzle and the drive plate.

[0024] Figure 12 schematically shown Figure 3 An exploded view of the stop nozzle pin and the drive plate.

[0025] Figure 13 schematically shown Figure 3 Another exploded view of the stop nozzle pin and drive plate.

[0026] Figure 14 A cross-sectional view of the stop mechanism in the retracted position is shown schematically.

[0027] Figure 15 A schematic cross-sectional view of the stop mechanism in the actuated position is shown.

[0028] Figure 16 A perspective view of the nozzle tip with a spiral cooling system is shown schematically.

[0029] Figure 17 Another perspective view of the nozzle tip with a spiral cooling system is shown schematically.

[0030] Figure 18 schematically shown Figure 16 The nozzle tip in the image shows the spiral cooling system through the transparent portion.

[0031] Figure 19 schematically shown Figure 16 The nozzle tip has a cross-sectional view of a large central channel.

[0032] Figure 20 is a photograph of an article formed by an injection molding machine with a cutoff nozzle as described herein, wherein the main runner filler remains fully connected to the article.

[0033] Figure 20AThis is an enlarged view of the tip of the main flow channel in Figure 20. Detailed Implementation

[0034] The apparatuses, systems, arrangements, and methods disclosed in this document are described in detail by way of example and with reference to the accompanying drawings. It will be understood that modifications may be made to the disclosed and described examples, arrangements, configurations, components, elements, apparatuses, methods, materials, etc., and may be desired for particular applications. Any designation of a particular technique, arrangement, method, etc. in this disclosure is either related to the specific example given or is merely a general description of such technique, arrangement, method, etc. Designations of specific details or examples are not intended to be, and should not be construed as, mandatory or limiting unless specifically indicated. Selected examples of shut-off nozzles for injection molding processes used in foamed polymer molded products and parts are disclosed and described in detail below with reference to Figures 1 through 20.

[0035] This paper discloses a novel shut-off nozzle for injection molding systems that efficiently processes and foams polymers to form final products and parts. The novel arrangement of the shut-off nozzle's shut-off mechanism and cooling system increases cell nucleation during the foaming process, increases pressure drop as the polymer is injected into the mold to promote cell growth and stabilization, limits drooling at the end of each injection cycle, and allows polymer remaining in the nozzle tip between cycles to solidify, promoting ejection of the solidified polymer before subsequent cycles.

[0036] Polymer foams, more specifically thermoplastic foams, are formed by saturating a polymer with gas while it is in a molten state. One mechanism for this saturation is by mixing the polymer with a blowing agent, where the gas is generated by a chemical reaction of the chemical blowing agent. Another mechanism is by injecting gas directly into the molten polymer stream, followed by rapid thermodynamic instability. These processes result in the formation of numerous transient nuclei. Due to pressure drop, the surface tension of the saturated molten polymer, and / or the normal or shear stress applied to the molten polymer, some of these nuclei develop into cell growth. Such cell growth results in voids in the final molded product, which advantageously reduces the density and thus the weight of the final molded product. The parameters mentioned above affect the value of the desired critical radius (r*) of the cells. If the injection molding process results in an increase in cells with radii greater than the critical radius, more cells will progress to the accelerated growth stage, leading to successful foaming and weight reduction in the final molded product. Conversely, if more cells have radii smaller than the critical radius, the cells will dissipate, reducing the probability of successful foaming and weight reduction in the final molded product. One important parameter controlled through the design of the shut-off nozzle in the foaming process is the level of additional stress (normal stress and shear stress) exerted on the molten polymer as it passes through the injection molding machine. Therefore, the design of the flow channels within the shut-off nozzle enables a more successful foaming process.

[0037] The novel shut-off nozzle disclosed herein produces higher molten polymer foaming and expansion, enabling more consistent injection of the molten foamed polymer into the mold cavity and providing excellent surface finish for the molded parts. Furthermore, the novel shut-off nozzle avoids the common problem of semi-solid plastic runner components remaining in the nozzle tip between cycles (i.e., the "cold slug segment"). This prevents a cold slug segment from being injected into the mold cavity in a subsequent molding cycle and negatively impacting the subsequently molded parts.

[0038] The cutoff nozzles and processes disclosed herein are well-suited for parts and assemblies that benefit from precise dimensions, consistent physical and mechanical properties, and flawless surfaces. Certain industries, such as medical devices (particularly those intended for use inside or implanted in the human body), automotive, aerospace, and other similar industries, tend to favor or require high dimensional accuracy and flawless surfaces. Furthermore, these industries place great emphasis on component consistency and structural integrity. As discussed herein, injection molding machines using prior art cutoff nozzles often result in inconsistent foaming properties of polymers processed by the injection molding machine, producing inferior molded parts that often include significant surface defects and structural integrity issues. A photograph in Figure 2 depicts an example of a common surface defect in foamed polymer parts molded using prior art cutoff nozzles (such as cutoff nozzle 100 shown in Figure 1). It can be understood that when the distance between the pin 30 cutting off the molten polymer flow and the nozzle tip 60 (denoted as D1 in Figure 1) is large, and the molten polymer in the nozzle tip is not sufficiently cooled and solidified, the ejection of remaining material is ineffective or inefficient. This results in a portion of the cold material remaining in the nozzle tip between injection cycles. Cold slug segments typically remain as long, filamentous residues. In the next injection cycle, these segments are injected into the mold cavity in a semi-solid state. The cold slug segments often migrate to the furthest edges of the cavity, as shown in Figure 2. Such segments often result in significant irregularities or defects on the surface of the molded part 80. In other examples, the cold slug segments may be located within the body of the molded part, thus affecting its structural integrity. It is easy to understand that such results lead to inferior foam-molded parts and components, which may be unsuitable for industries that desire or require precision parts and components.

[0039] refer to Figure 3-19An exemplary embodiment of a shut-off nozzle 100 for an injection molding machine (not shown) is illustrated. It will be understood that this shut-off nozzle 100 is arranged to connect to the end of the injection molding machine and is designed to guide molten polymer from the injection molding machine to the cavity of the mold. In one embodiment, the shut-off nozzle 100 is arranged to connect to the injection molding machine via a threaded connection. The shut-off nozzle 100 includes a body 110, a nozzle tip body 120, and a nozzle tip 130. A flow channel 140 passes through the body 110, the nozzle tip body 120, and the nozzle tip 130 to provide a path for the molten polymer (typically a thermoplastic polymer) to flow from the injection molding machine to the mold. The polymer is fed into the flow channel 140 by a force provided by the reciprocating screw of the injection molding system. The shut-off nozzle 100 includes a plurality of heating elements, typically referred to as heating cylinders, positioned near the flow channel 140. For example, as Figure 4 As shown, four heating elements 150 are equidistantly distributed around the flow channel 140 within the body 110, applying heat to the body 110 to maintain a constant temperature for the polymer flowing through this portion of the flow channel 140. Additionally, four heating elements 160 are equidistantly distributed around the flow channel 140 throughout the entire nozzle tip body 120, applying heat to the nozzle tip body 120 and nozzle tip 130 to maintain a constant temperature for the polymer flowing through this portion of the flow channel 140. The heating elements 150 and 160 are arranged to maintain the polymer in a constant molten state throughout the flow channel 140 as the polymer passes through the stop nozzle 100.

[0040] The shut-off nozzle 100 includes a pair of temperature sensors 170, 180 located within the nozzle tip body 120. The first temperature sensor 170 is located approximately at the midpoint of the nozzle tip body 120 and extends downward into the flow channel 140, allowing it to directly measure the temperature of the polymer flowing through the flow channel 140. The second temperature sensor 180 is located near the intersection of the body 110 and the nozzle tip body 120, providing an approximate measurement of the temperature of the polymer as it leaves the body 110 and enters the nozzle tip body 120. The control unit can receive and analyze the temperature measurements from the pair of temperature sensors 170, 180 and make any necessary adjustments to the heating elements 150, 160 positioned in the body 110 and / or the nozzle tip body 120.

[0041] When the molten polymer reaches the end of the shut-off nozzle 100, it is periodically injected into the mold cavity through the nozzle tip 130. When the polymer processed through the shut-off nozzle 100 has low viscosity or high melt flow index (e.g., polymer foam), the injection molding process benefits from the shut-off mechanism incorporated in the runner. This shut-off mechanism, in its retracted state, allows the molten polymer to flow through the nozzle tip 130 and into the mold during each injection cycle, but in its actuated state, it blocks the flow of the molten polymer between injection cycles.

[0042] Figure 5 and Figure 6 A schematic cross-sectional view of a novel shut-off mechanism 190 for a shut-off nozzle 100 is shown. The shut-off mechanism 190 includes a pin 200 located in a channel 210, wherein the pin 200 and the channel 210 are positioned at an angle to the flow path 140 such that when the pin 210 is actuated, it intersects with the molten polymer flow in the flow path 140 at a location closer to the nozzle tip 130 than in prior art shut-off nozzles. Figure 6 (Represented as D2). As shown, channel 210 extends across runner 140. A stop block 220 is located in this portion of channel 210 extending across runner 140. The stop block 220 includes a surface positioned near runner 140, which is arranged to engage with the guide surface of pin 210 when pin 210 is actuated. The engaging surfaces of pin 210 and stop block 220 are arranged to facilitate a clean cut-off of the molten polymer flow through runner 140 and prevent any polymer from flowing upwards into channel 210. At the end of each injection cycle, the overall arrangement of the stop mechanism 190 significantly reduces the volume of molten polymer located between the stop position and the end of nozzle tip 130. Runner 140 has a constant diameter before and after the intersection of channel 210 and runner 140. This constant diameter prevents premature and inefficient bubble nucleation as polymer flows through runner 140 and into the mold cavity.

[0043] Figure 7 A cutoff nozzle 100 with a transparent nozzle tip body 120 is schematically shown, revealing the internal cutoff mechanism 190. Figure 8 An enlarged view of the shut-off mechanism 190 is schematically shown. The shut-off mechanism 190 can be actuated and retracted by a control unit, for example, using a connection between the inlet 230 and the outlet 240 (e.g., Figure 9 (As shown) pneumatic or hydraulic power. The control unit can actuate pin 200 to cut off the flow of molten polymer and engage the fixed stop 220 at the end of each injection cycle, and can subsequently retract pin 200 at the beginning of each injection cycle to allow molten polymer to flow through runner 140, out of nozzle tip 130 and into mold. It will be understood that pin 200 can be actuated and driven through channel 210 to intersect runner 140 by distributing pneumatic or hydraulic power.

[0044] A mechanical mechanism for actuating the pin 200 and retracting it through the channel 210 includes a series of linear gear teeth 250 located below the pin 200, and a drive plate 260 including a series of linear gear teeth 270 that engage with the linear gear teeth 250 of the pin 200. Figure 10 and Figure 11The engagement of the linear gear teeth 250 of pin 200 with the linear gear teeth 270 of drive plate 260 is shown. Figure 12 and Figure 13 An exploded view of pin 200 and drive plate 260 is shown. Drive plate 260 includes a plurality of grooves 280 on its outer surface to accommodate lubricants such as oil or grease, thereby facilitating smooth movement of drive plate 260 during actuation and retraction.

[0045] Figure 14 The drive plate 260 and pin 200 are shown in the retracted position, while Figure 15 The drive plate 260 and pin 200 are shown in the actuated position. When pneumatic or hydraulic pressure is applied to the drive plate 260, the drive plate 260 moves to the left (relative to the left). Figure 8 , 14 And 15 in the direction of arrow A). It can be understood that the linear gear teeth 270 of the drive plate 260 are at an angle to the direction of movement of the drive plate 260. Therefore, when the drive plate 260 moves in the direction of arrow A, the engagement of the linear gear teeth 270 of the drive plate 260 and the linear gear teeth 250 of the pin 200 drives the pin 200 upward toward and through the flow channel 140. When the pneumatic or hydraulic pressure is removed, the drive plate 260 retracts to the right (relative to...). Figure 8 , 14 And 15 in the opposite direction of arrow A). When the drive plate 260 moves in the opposite direction of arrow A, the engagement of the linear gear teeth 270 of the drive plate 260 and the linear gear teeth 250 of the pin 200 causes the pin 200 to retract, the pin 200 moves downward away from the flow channel 140 and returns the pin 200 to its unacted position (as shown in the image). Figure 6 and Figure 14 (As shown). The movement of the drive plate 260 is actuated by applying hydraulic or pneumatic force via inlet 230 and outlet 240. To actuate the pin 200 by moving the drive plate 260 in the direction of arrow A, hydraulic or pneumatic fluid is injected through inlet 230 to apply a positive force to the drive plate 260. To retract the pin 200 by moving the drive plate 260 in the opposite direction of arrow A, the hydraulic or pneumatic fluid is emptied through outlet port 240, which applies a back pressure or negative force to the drive plate 260.

[0046] In another embodiment, the actuation of pin 200 can be directly driven by applying pneumatic or hydraulic pressure, and pin 200 is retracted by a biasing member such as a spring (not shown). This means that when the pneumatic or hydraulic power is removed, the spring will retract pin 200 and return it to its retracted position (e.g., Figure 6 (As shown). The spring is arranged such that when pin 200 is actuated and moves upward to intersect with flow channel 140, the spring extends. Therefore, when the pneumatic or hydraulic power is removed, the spring returns to its natural position and retracts pin 200.

[0047] In addition to the new angled stop mechanism 190, the stop nozzle also includes, for example, Figures 16 to 19 The novel nozzle tip 130 is shown. The nozzle tip 130 is partially positioned within the nozzle tip body 120 such that the internal channel 300 within the nozzle tip 130 is aligned with the flow channel 140. The nozzle tip 130 includes a novel cooling mechanism 310 formed within it. At the end of each injection cycle, this cooling mechanism rapidly cools and solidifies the molten polymer remaining in the flow channel 140 and the internal channel 300 of the nozzle tip 130, located between the actuated pin 200 of the stop mechanism 190 and the end of the nozzle tip 130. This rapid cooling and solidification process forms a solidified cold polymer segment that can be effectively ejected along with the part between injection cycles. The cooling process is arranged to be fast enough to significantly reduce or eliminate drooling and improve the injection molding process.

[0048] As described above, four heating elements 160, such as cartridge heaters, are positioned within the nozzle tip body 120 to precisely maintain the polymer temperature flowing through the internal channels 300 of the flow channel 140 and nozzle tip 130 during each injection cycle. At the end of each injection cycle, the pin 200 of the shut-off mechanism 190 is actuated to cut off the flow of polymer through the flow channel 140. The heating elements 160 are turned off and the cooling system is activated to rapidly solidify any polymer remaining in the internal channels 300 of the flow channel 140 and nozzle tip 130.

[0049] Figure 16 and Figure 17 A perspective view of a nozzle tip 130 is shown. The nozzle tip 130 includes a threaded portion 320 on its outer diameter. The threaded portion 320 is used to secure the nozzle tip 130 to the nozzle tip body 120. The nozzle tip 130 also includes a first port 330 and a second port 340 (e.g., ...). Figure 17 (As shown). The first port 330 can be connected to a fluid source to direct fluid into the cooling unit 310, while the second port 340 can be connected to a fluid line to drain fluid from the cooling unit. Reference Figure 18 and Figure 19 The cooling mechanism 310 of the nozzle tip 130 includes a highly efficient spiral water-cooling circuit surrounding an internal channel 300 of the nozzle tip 130. The cooling mechanism 310 comprises a continuous double spiral. The initial portion of the spiral receives cold water or other fluid input through a first port 330 and moves the cold water from the rear end of the nozzle tip 130 to the front end. Once the spiral reaches the front end of the nozzle tip 130, the spiral reverses direction and moves the fluid back towards the rear end of the nozzle tip 130, where the fluid exits the nozzle tip 130 through a second port 340.

[0050] When cold water, cool water, or other fluid is introduced into the spiral and travels through the nozzle tip 130, the fluid removes heat from the polymer remaining in the internal channels 300 of the nozzle tip 130. The continuous double-spiral construction of the cooling mechanism 310 passes through the nozzle tip 130 twice, which removes even more heat from the polymer in the internal channels 300 of the nozzle tip 130. Therefore, this process results in the rapid cooling and solidification of residual molten material, which will be ejected or otherwise removed before subsequent injection cycles. The cooling effect of the cooling mechanism 310 not only cools and solidifies the polymer in the internal channels 300, but also cools and solidifies the polymer in the flow path 140 between the actuated pin 200 and the nozzle tip.

[0051] To prepare for the next injection cycle, four heating elements 160 in the nozzle tip 130 are activated to heat the nozzle tip 130, thereby preparing for additional polymer flow through the nozzle tip 130. The internal channel 300 is a large channel designed to prevent premature and inefficient cell nucleation as polymer is injected into the mold cavity during the injection cycle. The flow path 140, which flows through a large portion of the shut-off nozzle, and the internal channel 300, which passes through the nozzle tip 140, maintain a constant diameter and cross-sectional area along their length, which further prevents premature and inefficient cell nucleation when the molten polymer is ready to be injected into the mold cavity.

[0052] like Figure 17 As shown, the rear surface of the nozzle tip 130 includes two concentric grooves 350 and 360. The first groove 350 is positioned between the first port 330 and the second port 340 and the internal channel 300. The second groove 360 ​​is positioned between the first internal port 330 and the second internal port 340 and the outer surface of the nozzle tip 130. O-rings or similar washers may be placed in each groove 350 and 360 to prevent cooling fluid from leaking into the internal channel 300 or onto the outside of the nozzle tip 130.

[0053] Figure 20 is a photograph of an article manufactured using the new type of shut-off nozzle, which has the main runner briquettes completely preserved. Figure 20A This is an enlarged view of the portion of the main runner solidified material that interacts with pin 200. The main runner solidified material represents the cured polymer remaining in the internal channel 300 of nozzle tip 130 and the flow channel 140 located between the actuated pin 200 and nozzle tip 130 at the end of each injection cycle and cooling period. As shown in the photograph, there is a clean cut at the polymer material, rather than the filamentous residue present when using prior art stop nozzles. Therefore, the novel stop nozzle 100 remedies the irregularities caused by using prior art stop nozzles.

[0054] The foregoing illustrative examples are provided for purposes of illustration and description. They are not intended to be exhaustive or to limit the application to the forms described. Many modifications are possible in light of the foregoing teachings. Some of these modifications have been discussed, while others will be understood by those skilled in the art. These examples were chosen and described to best illustrate the principles of the various examples to suit their intended specific use. Of course, the scope of protection is not limited to the examples set forth herein, but can be used by those skilled in the art in any number of applications and equivalent devices.

Claims

1. A shut-off nozzle, characterized in that, include: main body; The nozzle tip body extends from the main body; The flow channel passing through the main body and the nozzle tip body; The nozzle tip is partially positioned within the nozzle tip body; as well as Ending institutions include: A channel that intersects the flow path at an angle; as well as A pin positioned in the channel.

2. The shut-off nozzle according to claim 1, characterized in that, The intersection of the channel and the flow path is near the nozzle tip.

3. The shut-off nozzle according to claim 1, characterized in that, The stopping mechanism is arranged to move the pin between a retracted position and an actuated position.

4. The shut-off nozzle according to claim 3, characterized in that, When the pin is in the actuated position, the pin intersects with the flow channel, so that no material can flow through the intersection of the channel and the flow channel.

5. The shut-off nozzle according to claim 4, characterized in that, When the pin is in the retracted position, the pin does not intersect the flow channel, and material can flow through the intersection of the channel and the flow channel.

6. The shut-off nozzle according to claim 3, characterized in that, The control unit moves the pin between the retracted position and the actuated position.

7. The shut-off nozzle according to claim 1, characterized in that, The flow channel near the intersection of the channel and the flow path has a generally consistent diameter.

8. The shut-off nozzle according to claim 1, characterized in that, It also includes a first temperature sensor and a second temperature sensor.

9. The shut-off nozzle according to claim 8, characterized in that, The first temperature sensor is positioned in the nozzle tip body to measure the temperature of the nozzle tip body.

10. The shut-off nozzle according to claim 9, characterized in that, The second temperature sensor is positioned approximately at the midpoint of the nozzle tip body and extends into the flow channel to measure the temperature of the material passing through the flow channel.

11. The shut-off nozzle according to claim 10, characterized in that: One or more heating elements are positioned in the body to heat the flow channel; and One or more heating elements are positioned in the nozzle tip body to heat the flow channel.

12. The shut-off nozzle according to claim 11, characterized in that, The control unit monitors the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor, and adjusts the one or more heating elements located in the body and the one or more heating elements located in the nozzle tip body based on the temperature measurement results.

13. The shut-off nozzle according to claim 1, characterized in that, The nozzle tip includes: Internal passageways; and Cooling mechanism.

14. The shut-off nozzle according to claim 13, characterized in that, The internal channel is connected to the flow channel, and the axis of the internal channel is collinear with the axis of the flow channel, and the diameter of the internal channel is equal to the diameter of the flow channel.

15. The shut-off nozzle according to claim 13, characterized in that, The cooling mechanism includes a spiral circuit arranged to receive a fluid flow passing through the spiral circuit.

16. The shut-off nozzle according to claim 15, characterized in that, The spiral circuit begins at the first end of the nozzle tip, extends to the second and opposite ends of the nozzle tip, and returns to the first end of the nozzle tip.

17. The shut-off nozzle according to claim 16, characterized in that, As the fluid flows through the spiral circuit, heat from the internal channels and the nozzle tip is transferred to the fluid.

18. The shut-off nozzle according to claim 17, characterized in that, When heat is transferred from the internal channel and the nozzle tip to the fluid, any molten polymer in the internal channel solidifies.

19. The shut-off nozzle according to claim 18, characterized in that, When heat is transferred from the internal channel and the nozzle tip to the fluid, any molten polymer in the flow channel between the nozzle tip and the intersection of the flow channel and the channel solidifies.

20. The shut-off nozzle according to claim 19, characterized in that, When the molten polymer in the internal channel and the molten polymer in the channel between the nozzle tip and the flow channel solidify, the solidified polymer can be ejected from the shut-off nozzle as a continuous whole.

21. A nozzle tip for a shut-off nozzle, characterized in that, The nozzle tip includes: main body; The internal passageway through the main body; Cooling mechanism; For receiving fluid into the inlet port of the cooling mechanism; and An outlet port for discharging fluid from the cooling mechanism.

22. The nozzle tip according to claim 21, characterized in that, The cooling mechanism includes a spiral circuit arranged to receive a fluid flow passing through the spiral circuit.

23. The nozzle tip according to claim 22, characterized in that, The spiral circuit begins at the inlet port at the first end of the nozzle tip, extends to the second and opposite ends of the nozzle tip, and returns to the outlet port at the first end of the nozzle tip.

24. The nozzle tip according to claim 23, characterized in that, As the fluid flows through the spiral circuit, heat from the internal channels and the nozzle tip is transferred to the fluid.

25. The nozzle tip according to claim 24, characterized in that, When heat is transferred from the internal channel and the nozzle tip to the fluid, any molten polymer in the internal channel solidifies.

26. The nozzle tip according to claim 21, characterized in that, Also includes: A first groove is positioned between the internal channel and the inlet port and the outlet port; as well as A second groove is positioned between the outer surface of the nozzle tip and the inlet port and the outlet port.

27. The nozzle tip according to claim 26, characterized in that, Also includes: The first O-ring is positioned in the first groove; as well as The second O-ring is positioned in the second groove.

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