Injection molding nozzle for thermoplastics

Abstract

The present invention discloses an injection molding machine nozzle for thermoplastics, comprising a nozzle body, a first nozzle, a second nozzle, a third nozzle, a feeding cavity from the nozzle end to the nozzle tail, and a heating cavity opened on the nozzle body wall. In the original state, only the first nozzle is in a working state. If the first nozzle is blocked, the pressure in the feeding cavity increases, and the spring piece 1 inside the second nozzle is broken and enters the working state; the same is true for the remaining nozzles, which can enter the working state in sequence. The present invention has a simple structure. By arranging multiple nozzles and using them in stages, the effective continuous operation time of the injection molding machine is significantly prolonged, that is, the service life of the nozzle is prolonged and the effective process time is greatly increased.

Description

Technical Field

[0001] The invention relates to the application field of injection molding, in particular to an injection molding machine nozzle for thermoplastic plastics. Background Art

[0002] The main molding equipment for making thermoplastics into plastic products of various shapes is the injection molding machine and the plastic molding mold. When working, it needs to melt the solid raw materials and then inject them into the mold through the feeding pipe and nozzle for molding. The most important thing in the injection molding machine is the injection nozzle, which bears the most core technology in the injection molding process. In the currently commonly used injection molding equipment, generally after the injection is completed, the molten plastic retained at the nozzle is easy to block the injection hole, so it takes time to clean the nozzle, which takes a lot of time and energy, wastes resources and is inconvenient to operate; in addition, it is troublesome to deal with the blockage, and cleaning or replacing the nozzle will waste a lot of process time, and it will also cause serious hidden dangers to product quality. Summary of the invention

[0003] In order to solve the above problems, an object of the present invention is to provide an injection molding nozzle for thermoplastics.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A nozzle for an injection molding machine for thermoplastic plastics, comprising a nozzle body (1), a first nozzle (2), a second nozzle (3), a third nozzle (4), a feeding cavity (5), and a heating cavity (6); the second nozzle (3) is composed of a plunger 1 (3-1), a spring 1 (3-2), a plunger storage cavity 1 (3-3), and a flow channel 1 (3-4); the third nozzle (4) is composed of a plunger 2 (4-1), a spring 2 (4-2), a plunger storage cavity 2 (4-3), and a flow channel 2 (4-4); a heating wire (7) is provided in the heating cavity (6), and the heating wire (7) is connected to an external power source through an interface (8) provided on the wall of the nozzle; the specific working state of the nozzle is as follows:

[0006] a. In the original state, only the first nozzle (2) of the injection molding machine nozzle is in working state, and the second nozzle (3) and the third nozzle (4) are blocked by the plunger 1 (3-1) and the plunger 2 (4-1) respectively and are in a closed state.

[0007] b. When the first nozzle (2) is blocked, the internal pressure of the feeding chamber (5) continues to increase due to the continuous feeding. When the pressure reaches the maximum shear strength of the spring 1 (3-2) built into the second nozzle (3), the spring 1 (3-2) will be broken, and the plunger 1 (3-1) and the broken spring 1 (3-2) will be squeezed into and blocked in the plunger storage chamber 1 (3-3), and the second nozzle (3) will enter the working state;

[0008] c. When the second nozzle (3) is blocked, the internal pressure of the feeding chamber (5) continues to increase due to the continuous feeding. When the pressure reaches the maximum shear strength of the spring 2 (4-2) built into the third nozzle (4), the spring 2 (4-2) will be broken, and the plunger 2 (4-1) and the broken spring 2 (4-2) will be squeezed into and blocked in the plunger storage chamber 2 (4-3), and the third nozzle (4) will enter the working state.

[0009] Furthermore, the maximum shear strength (B bar) of the spring piece 1 (3-2) is greater than the normal working pressure (A bar) in the feed cavity, the maximum shear strength (C bar) of the spring piece 2 (4-2) is greater than the maximum shear strength of the spring piece 1 (3-2), and the maximum shear strength (C bar) of the spring piece 2 (4-2) is less than the shear strength (D bar) of the nozzle body (1), that is, A <B<C<D。

[0010] Furthermore, the spring piece 1 (3-2) is fixed in a dark groove provided on the inner wall of the plunger storage chamber 1 (3-3); the spring piece 2 (4-2) is fixed in a dark groove provided on the inner wall of the plunger storage chamber 2 (4-3).

[0011] Furthermore, the plunger 1 (3-1) and the plunger 2 (4-1) are respectively clearance-fitted with the inner walls of the first nozzle (3) and the second nozzle (4).

[0012] Furthermore, the plunger 1 (3-1) and the plunger 2 (4-1) are made of high temperature resistant material, and the lowest heat resistant temperature thereof is 20-50°C higher than the temperature of the material in the feed cavity (5).

[0013] Furthermore, the number of the nozzles other than the first nozzle is greater than or equal to 2.

[0014] Furthermore, there are flow channels (3-4) respectively between the plunger storage chamber 1 (3-3) and the nozzle body (1), and there is a flow channel (4-4) between the plunger storage chamber 2 (4-3) and the nozzle body (1).

[0015] Compared with the prior art, the present invention has the following advantages: the present invention has reasonable structural design and low manufacturing cost; a plurality of nozzles are provided and work is carried out in sequence under their corresponding working conditions, which can greatly improve the service life of the nozzles. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] Figure 2 It is a schematic diagram of the structure of the second nozzle in its original state.

[0018] Figure 3 It is a structural schematic diagram of the second nozzle in the working state.

[0019] The meanings of the reference numerals in the figure: 1 nozzle body, 2 first nozzle, 3 second nozzle, 4 third nozzle, 5 feed cavity, 6 heating cavity, 7 heating wire, 8 interface, 3-1 plunger 1, 3-2 spring piece 1, 3-3 plunger storage cavity 1, 3-4 flow channel 1, 4-1 plunger 2, 4-2 spring piece 2, 4-3 plunger storage cavity 2, 4-4 flow channel 2. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The present invention discloses a nozzle for an injection molding machine for thermoplastic plastics, comprising a nozzle body (1), a first nozzle (2), a second nozzle (3), a third nozzle (4), a feeding cavity (5), and a heating cavity (6); the second nozzle (3) is composed of a plunger 1 (3-1), a spring 1 (3-2), a plunger storage cavity 1 (3-3), and a flow channel 1 (3-4); the third nozzle (4) is composed of a plunger 2 (4-1), a spring 2 (4-2), a plunger storage cavity 2 (4-3), and a flow channel 2 (4-4); a heating wire (7) is arranged in the heating cavity (6), and the heating wire (7) is connected to an external power source through an interface (8) provided on the wall of the nozzle; the specific working state of the nozzle is as follows:

[0022] a. In the original state, only the first nozzle (2) of the injection molding machine nozzle is in working state, and the second nozzle (3) and the third nozzle (4) are blocked by the plunger 1 (3-1) and the plunger 2 (4-1) respectively and are in a closed state;

[0023] b. When the first nozzle (2) is blocked, the internal pressure of the feeding chamber (5) continues to increase due to the continuous feeding. When the pressure reaches the maximum shear strength of the spring 1 (3-2) built into the second nozzle (3), the spring 1 (3-2) will be broken, and the plunger 1 (3-1) and the broken spring 1 (3-2) will be squeezed into and blocked in the plunger storage chamber 1 (3-3), and the second nozzle (3) will enter the working state;

[0024] c. When the second nozzle (3) is blocked, the internal pressure of the feeding chamber (5) continues to increase due to the continuous feeding. When the pressure reaches the maximum shear strength of the spring 2 (4-2) built into the third nozzle (4), the spring 2 (4-2) will be broken, and the plunger 2 (4-1) and the broken spring 2 (4-2) will be squeezed into and blocked in the plunger storage chamber 2 (4-3), and the third nozzle (4) will enter the working state;

[0025] For example, the upper limit of the pressure of the feeding chamber (5) is 140 bar, the feeding pressure is 60 bar, the maximum shear strength of the spring 1 (3-2) is 100 bar, and the maximum shear strength of the spring 2 (4-2) is 110 bar:

[0026] When the injection molding machine starts to work, the heating wire (7) in the heating cavity (6) is connected to the external power supply through the interface (8) opened on the nozzle wall to heat the feed cavity. In the original state, only the first nozzle (2) is in working state. After a long period of continuous operation, the first nozzle (2) will be blocked. When the first nozzle (2) is blocked, the injection molding machine continues to work. At this time, the pressure in the feed cavity (5) will increase. When the pressure increases to 100 bar, the shrapnel 1 (3-2) will be broken by the plunger 1 (3-1), and the molten material will squeeze the plunger 1 (3-1) and the broken shrapnel 1 (3-2) into and block the plunger storage cavity (3-3). The second nozzle (3) starts to work, and the molten material will be ejected from the flow channel 1 (3-4);

[0027] After the second nozzle (3) has been working for a long time, it is inevitable that it will become clogged. At this time, the pressure in the feeding chamber will continue to increase. When the pressure in the chamber increases to 110 bar, the spring piece 2 (4-2) is broken by the plunger 2 (4-1), and the molten material squeezes the plunger 2 (4-1) and the broken spring piece 2 (4-2) into the plunger storage chamber (4-3) and blocks them. The third nozzle (4) starts to work, and the molten material is ejected from the flow channel 2 (4-4).

Claims

1. A nozzle for an injection molding machine for thermoplastic plastics, comprising a nozzle body (1), a first nozzle (2), a second nozzle (3), a third nozzle (4), a feeding cavity (5), and a heating cavity (6); the second nozzle (3) is composed of a plunger 1 (3-1), a spring 1 (3-2), a plunger storage cavity 1 (3-3), and a flow channel 1 (3-4); the third nozzle (4) is composed of a plunger 2 (4-1), a spring 2 (4-2), a plunger storage cavity 2 (4-3), and a flow channel 2 (4-4); a heating wire (7) is arranged in the heating cavity (6), and the heating wire (7) is connected to an external power supply through an interface (8) provided on the wall of the nozzle body (1); the specific working state of the nozzle is as follows: a. In the original state, only the first nozzle (2) of the injection molding machine nozzle is in working state, and the second nozzle (3) and the third nozzle (4) are blocked by the plunger 1 (3-1) and the plunger 2 (4-1), respectively, and are in a closed state; b. When the first nozzle is blocked, the internal pressure of the feeding chamber (5) continues to increase due to the continuous feeding. When the pressure reaches the maximum shear strength of the spring 1 (3-2) built into the second nozzle (3), the spring 1 (3-2) will be broken, and the plunger 1 (3-1) and the broken spring 1 (3-2) will be squeezed into and blocked in the plunger storage chamber 1 (3-3), and the second nozzle (3) will enter the working state; c. When the second nozzle is blocked, the internal pressure of the feeding chamber (5) continues to increase due to the continuous feeding. When the pressure reaches the maximum shear strength of the spring piece 2 (4-2) built into the third nozzle (4), the spring piece 2 (4-2) will be broken, and the plunger 2 (4-1) and the broken spring piece 2 (4-2) will be squeezed into and blocked in the plunger storage chamber 2 (4-3), and the third nozzle (4) will enter the working state; The plunger 1 (3-1) and the plunger 2 (4-1) are made of high temperature resistant material, and the lowest heat resistant temperature thereof is 20-50°C higher than the material temperature in the feeding cavity (5); The number of nozzles other than the first nozzle is greater than or equal to 2.

2. According to claim 1, a nozzle for an injection molding machine for thermoplastic plastics, the maximum shear strength B bar of the spring piece 1 (3-2) is greater than the normal working pressure A bar in the feeding cavity, the maximum shear strength C bar of the spring piece 2 (4-2) is greater than the maximum shear strength of the spring piece 1 (3-2), and the maximum shear strength C bar of the spring piece 2 (4-2) is less than the shear strength D bar of the nozzle body (1), that is, A bar. <B<C<D。 3. According to the injection molding nozzle for thermoplastic plastics described in claim 1, the spring piece 1 (3-2) is fixed in a dark groove set on the inner wall of the plunger storage chamber 1 (3-3); the spring piece 2 (4-2) is fixed in a dark groove set on the inner wall of the plunger storage chamber 2 (4-3).

4. According to the injection molding nozzle for thermoplastic plastics as described in claim 1, the plunger 1 (3-1) and the plunger 2 (4-1) are respectively in clearance fit with the inner walls of the first nozzle (2) and the second nozzle (3).

5. According to the injection molding machine nozzle for thermoplastic plastics described in claim 1, there is a flow channel 1 (3-4) between the plunger storage chamber 1 (3-3) and the nozzle body (1), and there is a flow channel 2 (4-4) between the plunger storage chamber 2 (4-3) and the nozzle body (1).

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