Injection molding machine and its nozzle

Abstract

The present invention provides an injection molding machine and a nozzle thereof. The nozzle has an inner flow channel and a spiral groove located inside the nozzle; the inner flow channel extends along the length direction of the nozzle and passes through both ends of the nozzle; the inner flow channel includes an inlet section, a main flow channel section and an outlet section that are sequentially connected along the length direction of the nozzle; the diameter of the main flow channel section is constant and smaller than the diameter of the inlet section; the spiral groove is arranged on the inner wall of the main flow channel section and communicates with the main flow channel section, and extends spirally around the main flow channel section, and one end of the spiral groove communicates with the inlet section; the spiral groove and the inner flow channel together constitute a channel for plastic melt to flow through. The nozzle of the present invention can homogenize the plastic melt.

Description

Technical Field

[0001] The invention relates to the technical field of injection molding equipment, in particular to an injection molding machine and a nozzle thereof. Background Art

[0002] The nozzle of the injection molding machine (full name: plastic injection molding machine) is a connecting device that guides the plastic melt plasticized by the plasticizing system into the molding cavity. In this device, the plastic melt in the inner flow channel needs to maintain a relatively stable physical and chemical state so that it can be stably injected into the mold cavity, which includes making the plastic melt have stable viscosity and uniformity. The inner flow channel hole of the nozzle commonly used in the industry is a smooth straight hole with one or more diameter changes, and it is required to be made as smooth and straight as possible to reduce flow resistance. At the same time, a layer of resistance heating coil or infrared heating coil and other heating elements are wrapped around the outer periphery of the nozzle to keep the nozzle body temperature fluctuation not too large. However, since the plastic melting process is nonlinear when the injection screw is plasticized, the melted plastic before injection is not completely homogeneous, showing a slightly higher center temperature than the outer layer, and the corresponding outer layer plastic temperature is lower and the viscosity is higher. In order to homogenize the plastic melt, some nozzles will add mixing elements such as filters and static mixers in the middle of the inner flow channel. Summary of the invention

[0003] Aiming at the problem that common nozzles of current injection molding machines can only play a connecting role, the shearing and mixing effect of the plastic melt flowing through is slight, and the nozzle with a filter and a static mixer has a large resistance along the way, the present invention provides a nozzle for an injection molding machine to solve the problem of uneven temperature and viscosity of the plastic melt flowing through the nozzle.

[0004] Another object of the present invention is to provide an injection molding machine having the above-mentioned nozzle.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] According to one aspect of the present invention, the present invention provides a nozzle for an injection molding machine, which comprises: an inner flow channel, which is located inside the nozzle, extends along the length direction of the nozzle and passes through both ends of the nozzle; the inner flow channel comprises an inlet section, a main flow channel section and an outlet section which are sequentially connected along the length direction of the nozzle; the diameter of the main flow channel section is constant and is smaller than the diameter of the inlet section; a spiral groove, which is arranged on the inner wall of the main flow channel section and communicates with the main flow channel section, and extends in a spiral shape around the main flow channel section, and one end of the spiral groove is communicated with the inlet section; the spiral groove and the inner flow channel together constitute a channel for plastic melt to flow through.

[0007] Wherein, the groove depth of the end of the spiral groove communicating with the inlet section is greater than the groove depth of the end away from the inlet section.

[0008] Wherein, as moving away from the inlet section, the groove depth of the spiral groove gradually decreases.

[0009] Wherein, one end of the spiral groove away from the inlet section is connected to the main flow channel section in a smooth transition.

[0010] The inlet section has a variable cross-section portion whose diameter gradually decreases in the direction toward the main flow channel section, the small end of the variable cross-section portion is connected to the main flow channel section, and the end of the spiral groove is connected to and communicated with the variable cross-section portion.

[0011] The cross section of the variable cross section portion is conical, and the end of the spiral groove is connected to the conical surface of the conical portion of the variable cross section portion.

[0012] Wherein, the helix angle of the spiral groove is 45° to 60°.

[0013] There are multiple spiral grooves, which are evenly distributed around the main channel section.

[0014] Wherein, the cross section of the spiral groove is arc-shaped.

[0015] According to another aspect of the present invention, the present invention provides an injection molding machine, comprising the nozzle as described above.

[0016] It can be seen from the above technical scheme that the present invention has at least the following advantages and positive effects: in the nozzle of the present invention, the inner flow channel and the spiral groove together constitute a channel for the plastic melt to flow through. When the plastic melt flows through the nozzle, the plastic melt still maintains a stratospheric state in the main flow channel section located in the center, and forms a vortex with a certain angle with the middle stratosphere in the spiral groove. On the one hand, the vortex increases the shear of the outer layer of the plastic melt, and the shear will generate shear heat, thereby increasing the temperature of the surface plastic melt and reducing the viscosity of the surface plastic melt; on the other hand, the vortex traveling along the spiral groove also drives the stratosphere to form a stable torsion, and finally the stratosphere also participates in the melt shearing. In the process of flowing along the length direction of the nozzle, the plastic melt undergoes multiple shearing and mixing processes, thereby forming a more homogeneous effect at the outlet section. The channel inside the nozzle is used as a whole for the plastic melt to pass through, and no mixing elements such as filters and static mixers are installed inside. The internal channel structure itself is directly used to increase the shear mixing effect of the plastic melt, thereby achieving a homogenizing effect of the plastic melt. Compared with the conventional nozzle solution of homogenizing the plastic melt using a mixing element, this solution does not add any parts, has a simpler structure, reliable strength, is easy to inspect and disassemble, and has a good cost advantage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a nozzle embodiment of the present invention.

[0018] Figure 2 yes Figure 1 Right view of .

[0019] Figure 3 yes Figure 2 AA section view.

[0020] Figure 4 The plastic melt flows through Figure 1 Schematic diagram of fluid distribution of the nozzle.

[0021] The reference numerals in the accompanying drawings are explained as follows: 1. Nozzle; 11. Positioning section; 111. External thread; 12. Operating section; 121. Temperature measuring hole; 122. Fixing hole; 13. Heating section; 14. Wedged into the mold section; 15. Internal flow channel; 151. Inlet section; 1511. Glue inlet; 1512. Glue inlet section; 1513. Variable cross-section section; 152. Main flow channel section; 153. Exit section; 1531. Spout; 1532. Tapered section; 1533. Spout section; 16. Spiral groove; 161. Arc-shaped opening. DETAILED DESCRIPTION

[0022] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially used for illustration purposes rather than for limiting the present invention.

[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0024] The invention provides a nozzle for an injection molding machine and an injection molding machine having the nozzle. The nozzle is connected between a plasticizing system and a molding die of the injection molding machine and is used to introduce plastic melt plasticized by the plasticizing system into a molding cavity of the molding die.

[0025] The plasticizing system includes, for example, a melt cylinder for melting plastic and a melt cylinder precursor for guiding the melted plastic. The specific structures of the melt cylinder and the melt cylinder precursor can be designed according to actual conditions. The molding mold is provided with a gate for receiving the plastic melt and a runner connecting the gate to the molding cavity. The gate, runner and molding cavity can be set according to actual needs.

[0026] The specific structure of the plasticizing system and the molding die is not limited here, and reference may be made to the relevant technology in the art. The present invention mainly relates to the improvement of the nozzle, and the following will mainly introduce the structure of the nozzle. The nozzle is connected between the melt cylinder precursor of the plasticizing system and the gate of the molding die. It is understandable that the nozzle can also be connected to the melt cylinder precursor and the gate respectively by adaptively designing the two ends of the nozzle.

[0027] See also Figures 1 to 3 The nozzle 1 of this embodiment is an integrated structure, which is generally a long columnar structure, and its interior is penetrated along its length direction to form a channel for the plastic melt to flow through.

[0028] For the convenience of description, the direction in which the plastic melt flows inside the nozzle 1 is defined as flowing from the rear end to the front end. Figure 1 As a reference, the right side of the diagram is the "back" direction and the left side is the "front" direction.

[0029] Combination Figure 1 and Figure 2 The nozzle 1 is divided into a positioning section 11, an operating section 12, a heating section 13 and a wedging mold section 14 from the rear end to the front end.

[0030] The positioning section 11 is used to connect the melt cylinder precursor of the plasticizing system (not shown in the figure), and can be adaptively designed according to the structure of the melt cylinder precursor. Generally, the positioning section 11 is cylindrical in shape, and the outer surface of the middle area of ​​the positioning section 11 is provided with an external thread 111, so that it can be connected and assembled with the mounting threaded hole inside the melt cylinder precursor.

[0031] The operating section 12 is for the operator to operate. In this embodiment, the outer periphery of the operating section 12 is hexagonal and can be adapted to be connected with a wrench. Thus, when the nozzle 1 is connected to the melt tube precursor for assembly or disassembly, the operator can use a wrench to connect the operating section 12 for assembly and disassembly, which is convenient for operation.

[0032] The outer circumference of the heating section 13 is cylindrical, and heating elements such as heating coils and / or other heat preservation facilities can be installed on the outer surface of the heating section 13. By controlling the start and stop of the heating element, the nozzle 1 can be kept at a relatively stable temperature during operation. According to the structural requirements of the heating element or other heat preservation facilities, the outer surface of the heating section 13 can be adaptively designed with some matching structures such as holes, grooves, protrusions, etc.

[0033] The start and stop of the heating element can be controlled by a set timing, or can be controlled in real time based on the temperature detection of the nozzle 1. For example, in this embodiment, a temperature measuring hole 121 can be opened on the nozzle 1, and a temperature measuring element such as a thermocouple can be used to detect the temperature to control the heating element. Figure 3 A temperature measuring hole 121 and a fixing hole 122 connected to the temperature measuring hole 121 are provided on the operating section 12. The fixing hole 122 is used to install a temperature measuring element and the temperature measuring element can be inserted into the temperature measuring hole 121 for temperature measurement. It can be understood that the position of the temperature measuring hole 121 can be set according to actual conditions and is not limited to the operating section 12.

[0034] The wedging mold segment 14 is used to connect the gate of the molding mold (not shown in the figure), and the cross section of the wedging mold segment 14 is circular, and it has a smaller outer profile than the other sections of the nozzle 1. The front end of the wedging mold segment 14 is roughly spherical, and contacts with the gate to form a near seal.

[0035] The above mainly introduces the appearance structure of the nozzle 1. Based on the above description, it can be seen that the appearance of the nozzle 1 is mainly used to cooperate with external structural parts. Based on the different structural forms of the external structural parts, the appearance of the nozzle 1 can be adaptively adjusted and designed.

[0036] See next Figure 3 The nozzle 1 has an inner flow channel 15 that runs through the front and rear ends of the nozzle 1 and a spiral groove 16 that surrounds the inner flow channel 15. The inner flow channel 15 and the spiral groove 16 together constitute a channel for the plastic melt to flow through.

[0037] The inner flow channel 15 extends along the length direction of the nozzle 1, and includes an inlet section 151, a main channel section 152 and an outlet section 153 which are sequentially connected from the rear end to the front end along the length direction of the nozzle 1. The cross section of the inner flow channel 15 at various locations along its length direction is usually set to be circular, with less resistance.

[0038] The inlet section 151 passes through the rear end face of the nozzle 1 and forms a glue inlet 1511 on the rear end face of the nozzle 1. When the positioning section 11 is connected to the melt glue cylinder precursor of the plasticizing system, the glue inlet 1511 will be connected to the glue outlet in the melt glue cylinder precursor, thereby receiving the plastic melt flowing from the melt glue cylinder precursor.

[0039] The inlet section 151 has a glue inlet 1512 with a constant diameter and a variable cross-section portion 1513 with a gradually decreasing diameter. The rear end of the glue inlet 1512 forms the glue inlet 1511, and the front end of the glue inlet 1512 is connected to the rear end of the variable cross-section portion 1513. The diameter of the variable cross-section portion 1513 gradually decreases in the direction from the rear end to the front end. Through this structural form, the plastic melt is guided to increase the flow rate of the plastic melt. In this embodiment, the longitudinal section of the variable cross-section portion 1513 is conical, and the diameter changes evenly.

[0040] The length of the main channel section 152 occupies a large proportion of the total length of the inner channel 15. As an example, the proportion may be approximately 70%. The diameter of the main channel section 152 is constant, and the rear end of the main channel section 152 is connected to the front end of the variable cross-section portion 1513 of the inlet section 151. That is, the main channel section 152 is connected to the small end of the variable cross-section portion 1513 with a smaller diameter. Accordingly, it can also be said that the diameter of the main channel section 152 is smaller than the diameter of the inlet section 151.

[0041] The outlet section 153 penetrates the front end face of the nozzle 1 and forms a nozzle 1531 on the front end face of the nozzle 1. When the wedged mold section 14 is connected to the molding mold, the nozzle 1531 will be connected to the runner of the molding mold, so that the plastic melt can be sprayed into the mold cavity of the molding mold. The outlet section 153 has a tapered portion 1532 connected to the main channel section 152 and a nozzle portion 1533 connected to the tapered portion 1532. The diameter of the tapered portion 1532 gradually decreases in the direction away from the main channel section 152, and the diameter of the nozzle portion 1533 is constant. The front end of the nozzle portion 1533 forms the nozzle 1531. The diameter of the outlet section 153 is smaller than that of the main channel section 152, so that the flow rate of the plastic melt is further accelerated to be sprayed into the molding mold.

[0042] The spiral groove 16 is arranged on the inner wall of the main channel section 152 and communicates with the main channel section 152, that is, the spiral groove 16 is formed by the inner wall of the main channel section 152 being further recessed toward the outer surface of the nozzle 1. In the length direction of the main channel section 152, the spiral groove 16 extends in a spiral shape around the main channel section 152. The rear end of the spiral groove 16 is communicated with the inlet section 151, and the front end of the spiral groove 16 terminates at the main channel section 152 and is spaced from the outlet section 153. By using the spiral groove 16, the plastic melt can form a vortex therein, thereby increasing the shearing effect on the surface of the plastic melt, which will be described in detail below. Preferably, the spiral angle of the spiral groove 16 is 45° to 60°, so that the blocking performance of the plastic melt is better and the influence on the speed of fluid flow is minimal.

[0043] In this embodiment, the rear end portion of the spiral groove 16 is connected to the conical surface of the variable cross-section portion 1513 of the inlet section 151 , so that the plastic melt flowing along the variable cross-section portion 1513 can smoothly enter the spiral groove 16 .

[0044] The groove depth at the rear end of the spiral groove 16 is preferably greater than the groove depth at the front end thereof. In some embodiments, the groove depth of the spiral groove 16 gradually decreases in the direction away from the inlet section 151. In other embodiments, the spiral groove 16 may also have some local areas where the groove depth remains constant.

[0045] The front end of the spiral groove 16 is preferably connected to the main flow channel section 152 in a smooth transition so that the plastic melt in the spiral groove 16 can smoothly flow into the main flow channel section 152 .

[0046] See also Figure 2 The number of spiral grooves 16 is preferably multiple and evenly distributed around the central axis of the main channel section 152. The figure shows three spiral grooves 16. In other embodiments, the number of spiral grooves 16 can be two to six. The specific design can refer to the actual situation such as the diameter of the main channel section 152, the material properties of the plastic melt, and the processing technology of the nozzle 1.

[0047] The cross section of the spiral groove 16 is arc-shaped, and the arc-shaped opening 161 thereof is connected to the inner wall of the main channel section 152, and the plastic melt is exchanged with the main channel section 152 through the arc-shaped opening 161. In the extending direction of the spiral groove 16, the size of the arc-shaped opening 161 at each location of the spiral groove 16 can also be changed accordingly according to the change of the groove depth.

[0048] Combination Figure 3 and Figure 4 When the nozzle 1 of this embodiment is in use, the plastic melt enters the inlet section 151 of the inner flow channel 15 through the glue inlet 1511, and flows from back to front along the glue inlet section 1512 and the variable cross-section section 1513 in sequence. Subsequently, most of the plastic melt enters the main flow channel section 152, and the flow of the plastic melt in the main flow channel section 152 is mainly in a laminar state, thereby forming a stratosphere M with a straight flow direction from back to front. A small part of the plastic melt enters the spiral groove 16. Since the spiral extension direction of the spiral groove 16 has an angle with the original flow of the plastic melt along the front-to-back direction, the plastic melt will be blocked by the groove wall of the spiral groove 16 in the front-to-back direction, so that part of the plastic melt will flow back along the groove wall of the spiral groove 16, and together with the plastic melt originally flowing forward, a vortex V is formed in the spiral groove 16. Since the spiral groove 16 is connected to the main channel section 152, part of the vortex V will merge into the stratosphere M of the main channel section 152, and part of the fluid in the stratosphere M will be squeezed into the spiral groove 16 under the action of the vortex V to form a new vortex V. The vortex V in the spiral groove 16 is also transmitted forward in a spiral along the extension direction of the spiral groove 16 until it is completely merged into the main channel section 152 with the termination of the spiral groove 16. Finally, all the plastic melt enters the outlet section 153, flows along the outlet section 153, and is ejected from the nozzle 1531.

[0049] Based on the above description, in the nozzle 1, the inner flow channel 15 and the spiral groove 16 together constitute a channel for the plastic melt to flow through. When the plastic melt flows through the nozzle 1, the plastic melt remains in the stratosphere state in the main flow channel section 152 located in the center, and a vortex with a certain angle with the middle stratosphere is formed in the spiral groove 16. On the one hand, the vortex increases the shear of the outer layer of the plastic melt, and the shear will generate shear heat, thereby increasing the temperature of the surface plastic melt and reducing the viscosity of the surface plastic melt; on the other hand, the vortex traveling along the spiral groove 16 also drives the stratosphere to form a stable torsion, and finally the stratosphere is also involved in the melt shearing. In the process of flowing along the length direction of the nozzle 1, the plastic melt undergoes multiple shearing and mixing processes, thereby forming a more homogeneous effect at the outlet section 153.

[0050] The entire channel inside the nozzle 1 is used for passing the plastic melt, and no mixing elements such as filters and static mixers are installed inside. The internal channel structure itself is directly used to increase the shear mixing effect of the plastic melt, thereby achieving a homogenization effect of the plastic melt. Compared with the conventional nozzle solution that uses mixing elements to homogenize the plastic melt, this solution does not increase parts, has a simpler structure, reliable strength, is easy to inspect and disassemble, and has a good cost advantage.

[0051] It is worth mentioning that in the present solution, the shearing action is mainly performed on the surface of the plastic melt, while most of the plastic melt in the main channel section 152 is only slightly twisted under the shearing action of the outer layer. From the cross section of the main channel section 152 surrounded by the spiral groove 16, the shearing action of the plastic melt is strong on the outside and weak on the inside. At the same time, since the spiral groove 16 is continuously rotated and extended in a spiral shape, the shearing action is also continuously rotating. Overall, the shearing action of the plastic melt is relatively mild. For temperature-sensitive plastics, the nozzle 1 of the present solution is not prone to overheating and decomposition during use. When glass fiber or carbon fiber reinforcement is added to the plastic melt, this type of shearing has a very slight effect on the breakage of such added components. The nozzle 1 is not prone to fiber breaking during use, and has little effect on the strength of the product, thereby improving the product quality reliability of the product.

[0052] In addition, the nozzle 1 of the present invention has a smooth internal flow channel with no dead angles and a reverse groove that can retain the plastic melt, so it is easy to change colors and clean materials, and it is not easy to cause discoloration and carbonization problems due to long-term retention and decomposition of the plastic melt.

[0053] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A nozzle for an injection molding machine, characterized in that: It has: An inner flow channel is located inside the nozzle, extends along the length direction of the nozzle and passes through both ends of the nozzle; the inner flow channel includes an inlet section, a main flow channel section and an outlet section which are sequentially connected along the length direction of the nozzle; the diameter of the main flow channel section is constant and smaller than the diameter of the inlet section; A spiral groove is arranged on the inner wall of the main flow channel section and communicates with the main flow channel section and extends spirally around the main flow channel section, one end of the spiral groove communicates with the inlet section; the spiral groove and the inner flow channel together constitute a channel for the plastic melt to flow through; There are multiple spiral grooves, which are evenly distributed around the main channel section, and the cross-section of the spiral groove is arc-shaped.

2. The nozzle according to claim 1, characterized in that: The groove depth of the spiral groove at one end communicating with the inlet section is greater than the groove depth at one end away from the inlet section.

3. The nozzle according to claim 2, characterized in that: The groove depth of the spiral groove gradually decreases as it moves away from the inlet section.

4. The nozzle according to claim 2, characterized in that: One end of the spiral groove away from the inlet section is connected to the main flow channel section in a smooth transition.

5. The nozzle according to claim 1, characterized in that: The inlet section has a variable cross-section portion whose diameter gradually decreases in a direction toward the main flow channel section, a small end of the variable cross-section portion is connected to the main flow channel section, and an end of the spiral groove is connected to and communicated with the variable cross-section portion.

6. The nozzle according to claim 5, characterized in that: The cross section of the variable cross section portion is tapered, and the end of the spiral groove is connected to the tapered surface of the tapered cross section portion.

7. The nozzle according to any one of claims 1 to 6, characterized in that: The helix angle of the spiral groove is 45° to 60°.

8. An injection molding machine, characterized in that: Comprising a nozzle as described in any one of claims 1-7.

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