A runner for resolving product jet marks and method of use thereof

Abstract

The application discloses a runner mode for solving product jet marks, and aims at solving the problem of jet marks caused by cold material in the transparent part injection molding process; high-temperature molten injection material is injected from an injection gate, and reaches a buffer groove with a tetrahedron shape with a triangular side view through a mold runner cavity; there is a temperature difference between the front end molten injection material and the mold runner cavity, and a little cold material will float after contact; when the molten injection material continues to flow forward under the pressure of the injection equipment, the buffer groove is arranged at a distance of 4-5 mm from the gate; when the molten injection material continues to flow forward under the pressure of the injection equipment, the cold material reaches the buffer groove, at this time, the cold material floating above the front molten injection material will stay in the buffer groove, and the rear molten injection material will continue to flow into the product cavity until the product is filled and finished, so that the jet marks caused by the cold material can be effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of transparent injection molded parts manufacturing technology, and in particular to a flow channel for solving product jetting marks and its application method. Background Technology

[0002] Injection molding is a method of industrial product manufacturing. Products typically use rubber injection molding and plastic injection molding processes. Among various injection-molded products, transparent injection-molded products are frequently used in the high-precision optical communication industry. Because transparent plastic raw materials often have high melting points and poor fluidity, fine adjustments are often needed to process parameters such as barrel temperature, injection pressure, and injection speed to ensure the surface quality of the plastic shell. Due to the high light transmittance required for transparent plastics, strict surface quality requirements are necessary, eliminating defects such as blemishes, pores, whitening, haze, black spots, discoloration, and poor gloss. Therefore, careful attention must be paid to the design of the plastic raw materials, injection equipment, plastic molds, and even the plastic shell throughout the entire injection molding process. Jetting marks are a common problem in transparent injection-molded parts. This is mainly caused by the presence of cooled and solidified cold material in the molten polymer, and the high-speed passage of the molten polymer through the nozzle, runner, or gate (which restricts flow) into the open area, resulting in a failure to achieve a tight fit with the mold wall. When plastic flows into the mold, it will appear as a white mist spray pattern. Too many spray patterns will lead to a decrease in the strength of the plastic part, and cause surface defects and internal flaws. At the same time, the misty marks on the product surface will prevent the product from meeting some industry quality standards that require transparency.

[0003] A search revealed Chinese patent publication number CN114434746A, which discloses a flow channel structure. This flow channel structure includes: a main flow channel; branch flow channels extending from the main flow channel; and secondary flow channels extending from the branch flow channels. The secondary flow channels include straight secondary flow channels and horn-shaped flow channels, with the horn-shaped flow channels communicating with the mold cavity to allow the injection of plastic into the cavity. A cold slug groove is located at the straight secondary flow channel, with its length perpendicular to the straight secondary flow channel and its depth extending downwards along the straight secondary flow channel. The aforementioned patent has a problem: because the cold slug groove, used to prevent cold material from entering the injection cavity, is located below the straight secondary flow channel, when the molten polymer is injected into the injection cavity, the cold material from the transparent plastic raw material floats, making it impossible to collect and prevent the cold material from entering the cavity. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a flow channel for resolving product jetting patterns and its application method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for using flow channels to solve product jetting marks includes the following steps: 1: High-temperature molten injection molding material is injected from the injection port, flows through the mold runner cavity, and reaches the buffer groove, which has a tetrahedral shape and a triangular side sectional view. 2: The temperature difference between the molten injection material and the mold runner cavity at the front end causes the molten injection material to continue flowing forward under the pressure of the injection molding equipment, while the cold material reaches the buffer tank. 3: The cold material floating above the molten injection molding material will remain in the buffer tank, while the molten injection molding material behind it will continue to flow into the product cavity. 4: Continue in this manner until the product is completely filled.

[0006] A flow channel for solving product jetting marks, wherein the mold flow channel cavity includes a main flow channel, a primary runner, a secondary runner, and a tertiary runner. One end of the main flow channel is connected to the port of an external injection molding equipment through an injection port. Multiple primary runners are fixedly connected below the main flow channel. Multiple secondary runners are fixedly connected to one end of the primary runners. Multiple tertiary runners are fixedly connected to one end of the secondary runners. This allows the high-temperature molten injection molding material entering from the injection port to be divided into multiple streams that flow into multiple product cavities for simultaneous injection molding.

[0007] Furthermore: a trapezoidal gate is fixedly connected to one end of the product cavity, the wider end of the gate is fixedly connected to the three-stage runner, and multiple bosses are provided at one end of the product cavity.

[0008] Furthermore, the distance between the top of the buffer tank and the discharge end of the gate is 4-5mm.

[0009] As a preferred embodiment of the present invention, the injection molding temperature is 200-250℃.

[0010] As a further aspect of the present invention: a buffer cavity is fixedly connected to one end of the main flow channel, the primary flow channel and the secondary flow channel. When the high-temperature molten injection molding material flows to the end of the main flow channel, the primary flow channel and the secondary flow channel, it will first enter the buffer cavity to reduce the flow speed before flowing to both sides.

[0011] As a further embodiment of the present invention: a buffer baffle is fixedly connected to one side of the buffer groove, and the horizontal height of the lower end of the buffer baffle is flush with the lower end of the product cavity.

[0012] Based on the aforementioned scheme: the injection pressure is 90-110MPa.

[0013] Based on the aforementioned scheme: the width of the buffer groove and the buffer baffle is the same as the diameter of the three-stage diversion channel.

[0014] Based on the aforementioned scheme: the mold runner cavity is a two-cavity mold, with the primary runner symmetrically installed below the main runner, the secondary runner symmetrically installed at one end of the primary runner, and the tertiary runner symmetrically installed at one end of the secondary runner.

[0015] The beneficial effects of this invention are as follows: 1. A flow channel for solving product jetting marks, by setting a buffer groove 4-5mm away from the gate, when the molten injection molding material continues to flow forward under the pressure of the injection molding equipment, the cold material reaches the buffer groove. At this time, the cold material floating above the molten injection molding material will stay in the buffer groove, and the molten injection molding material behind will continue to flow into the product cavity until the product is filled. This can effectively prevent jetting marks caused by cold material.

[0016] 2. A runner system for solving product jetting marks, wherein a flared gate reduces the flow rate of molten injection molding material, thereby reducing the impact on the product cavity.

[0017] 3. A flow channel for solving product jetting marks, which uses a buffer baffle with the lower edge of the baffle flush with the lower edge of the product cavity to form an overlapping gate. Combined with the flared shape of the gate, the molten injection molding material can spread outward in a fan shape after entering the product cavity instead of being directly sprayed in, which can make the movement smoother and reduce jetting marks.

[0018] 4. A flow channel for solving product jetting marks: by setting a buffer groove 4-5mm away from the gate outlet, it can effectively prevent new cold material from being generated when the molten injection molding material enters the product cavity after passing through the buffer groove. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the flow channel design structure for solving product jetting patterns and its application method proposed in this invention; Figure 2 This is a schematic diagram of a buffer groove for solving the jetting pattern of a product, as proposed in this invention, and its application method. Figure 3 This is a side view of a three-stage flow channel, which is proposed in this invention to solve the problem of product jetting patterns and its application method.

[0020] In the diagram: 1. Main runner; 2. Injection gate; 3. Primary runner; 4. Secondary runner; 5. Tertiary runner; 6. Buffer groove; 7. Product cavity; 8. Gate; 9. Buffer baffle; 10. Buffer chamber. Detailed Implementation

[0021] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0022] The embodiments of this patent are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this patent, and should not be construed as limiting this patent. Example 1

[0023] A method for using flow channels to solve product jetting patterns, such as Figures 1-3 As shown, it includes the following steps: 1: High-temperature molten injection molding material is injected from injection port 2 through injection molding equipment. The temperature of the high-temperature molten injection molding material is preferably 200-250 degrees Celsius, and the injection pressure is preferably 90-110MPa. The material passes through the mold runner cavity and reaches the buffer groove 6, which is a tetrahedral shape with a triangular side sectional view. 2: During the flow process, a temperature difference exists between the molten injection material at the front end and the mold runner cavity. Upon contact, a small amount of cold material will float. As the molten injection material continues to flow forward under the pressure of the injection molding equipment, the cold material reaches the buffer tank 6. 3: At this point, the cold material floating above the molten injection molding material will stay in the buffer tank 6, while the molten injection molding material behind it will continue to flow into the product cavity 7. 4: Continue until the product filling is complete; The mold flow channel cavity includes a main flow channel 1, a primary flow channel 3, a secondary flow channel 4, and a tertiary flow channel 5. One end of the main flow channel 1 is connected to the port of an external injection molding equipment through an injection port 2. Multiple primary flow channels 3 are fixedly connected below the main flow channel 1. Multiple secondary flow channels 4 are fixedly connected to one end of the primary flow channel 3, and multiple tertiary flow channels 5 are fixedly connected to one end of the secondary flow channel 4. The high-temperature molten injection molding material entering from the injection port 2 can be divided into multiple streams and flow into multiple product cavities 7 for simultaneous injection molding. At the same time, a buffer cavity 10 is fixedly connected to one end of the main flow channel 1, the primary flow channel 3, and the secondary flow channel 4. When the high-temperature molten injection molding material flows to the end of the main flow channel 1, the primary flow channel 3, and the secondary flow channel 4, it will first enter the buffer cavity 10 to reduce the flow speed before flowing to both sides.

[0024] To address the issue of excessively rapid injection speed of molten raw material into the product cavity 7 during injection molding; Figures 1-3As shown, a trapezoidal gate 8 is fixedly connected to one end of the product cavity 7. The wider end of the gate 8 is fixedly connected to the three-stage runner 5. Multiple bosses are provided at one end of the product cavity 7. The bosses can be used to collect air bubbles in the molten injection molding material. The gate 8 is shaped like a flared mouth, which can reduce the flow rate of the molten injection molding material and reduce the impact on the product cavity 7. The distance between the top of the buffer tank 6 and the outlet end of the gate 8 is 4-5mm, which can effectively prevent the molten injection molding material from generating new cold material when it enters the product cavity 7 after passing through the buffer tank 6.

[0025] To address the issue of better collecting cold material in buffer groove 6 and preventing cold material from entering product cavity 7; Figures 1-3 As shown, a buffer baffle 9 is fixedly connected to one side of the buffer groove 6. The horizontal height of the lower end of the buffer baffle 9 is flush with the lower end of the product cavity 7. The buffer baffle 9 can intercept and block the floating cold material from above the molten injection molding material. At the same time, the lower edge of the buffer baffle 9 is flush with the lower edge of the product cavity 7, so that the gate 8 and the product cavity 7 form an overlapping gate. With the flared shape of the gate 8, the molten injection molding material can spread outwards in a fan shape after entering the product cavity 7 instead of being directly sprayed in, which can make the movement smoother and reduce the spray marks.

[0026] When in use, this product effectively removes cold material from the molten injection molding material before it enters the product cavity 7 through the tetrahedral buffer groove 6. The buffer baffle 9 further improves the effect of intercepting and blocking floating cold material. At the same time, the lower edge of the buffer baffle 9 is flush with the lower edge of the product cavity 7, so that the gate 8 and the product cavity 7 form an overlapping gate. With the flared shape of the gate 8, the molten injection molding material can spread outwards in a fan shape after entering the product cavity 7 instead of being sprayed directly in, which can make the movement smoother and reduce spray marks. The flared shape of the gate 8 can reduce the flow rate of the molten injection molding material and reduce the impact on the product cavity 7. The distance between the top of the buffer groove 6 and the outlet end of the gate 8 is 4-5mm, which can effectively prevent the molten injection molding material from generating new cold material during the process of entering the product cavity 7 after passing through the buffer groove 6.

[0027] Example 2: A flow channel for solving product jetting patterns, such as Figures 1-3 As shown, this embodiment makes the following improvements based on embodiment 1: the width of the buffer trough 6 and the buffer baffle 9 is the same as the diameter of the three-stage diversion channel 5, which can increase the cold material capacity of the buffer trough 6; The mold runner cavity is a two-cavity mold. The primary runner 3 is symmetrically installed below the main runner 1, the secondary runner 4 is symmetrically installed at one end of the primary runner 3, and the tertiary runner 5 is symmetrically installed at one end of the secondary runner 4.

[0028] The above description represents a preferred embodiment of the present invention. The scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, combined with existing technology or common knowledge, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for using a flow channel to solve product jetting patterns, characterized in that, Includes the following steps: 1: High-temperature molten injection molding material is injected from the injection port (2), and reaches the buffer groove (6), which is a tetrahedral shape with a triangular side section view, through the mold runner cavity. 2: The temperature difference between the molten injection material at the front end and the mold runner cavity causes the cold material to reach the buffer tank (6) as the molten injection material continues to flow forward under the pressure of the injection molding equipment. 3: The cold material floating above the molten injection molding material will stay in the buffer tank (6), and the molten injection molding material behind will continue to flow into the product cavity (7). A buffer baffle (9) is fixedly connected to one side of the buffer tank (6). A trapezoidal gate (8) is fixedly connected to one end of the product cavity (7). The wider end of the gate (8) is fixedly connected to the three-stage runner (5). Multiple bosses are provided at one end of the product cavity (7). The horizontal height of the lower end of the buffer baffle (9) is flush with the lower end of the product cavity (7). The width of the buffer tank (6) and the buffer baffle (9) is the same as the diameter of the three-stage runner (5). 4: Continue in this manner until the product is completely filled.

2. The method for using a flow channel to solve product jetting patterns according to claim 1, characterized in that, The mold flow channel cavity includes a main flow channel (1), a primary flow channel (3), a secondary flow channel (4) and a tertiary flow channel (5). One end of the main flow channel (1) is connected to the port of an external injection molding equipment through the injection port (2). Multiple primary flow channels (3) are fixedly connected below the main flow channel (1). Multiple secondary flow channels (4) are fixedly connected to one end of the primary flow channel (3). Multiple tertiary flow channels (5) are fixedly connected to one end of the secondary flow channel (4). The high-temperature molten injection molding material entering from the injection port (2) can be divided into multiple streams and flow into multiple product cavities (7) for simultaneous injection molding.

3. The method for using a flow channel to solve product jetting patterns according to claim 1, characterized in that, The distance between the top of the buffer tank (6) and the discharge end of the gate (8) is 4-5mm.

4. The method for using a flow channel to solve product jetting patterns according to claim 1, characterized in that, The injection temperature in step 1 is 200-250℃.

5. The method for using a flow channel to solve product jetting patterns according to claim 2, characterized in that, One end of the main channel (1), the first-level branch channel (3) and the second-level branch channel (4) is fixedly connected to a buffer cavity (10). When the high-temperature molten injection molding material flows to the end of the main channel (1), the first-level branch channel (3) and the second-level branch channel (4), it will first enter the buffer cavity (10) to reduce the flow speed before flowing to both sides.

6. The method for using a flow channel to solve product jetting patterns according to claim 1, characterized in that, The injection pressure in step 2 is 90-110 MPa.

7. The method for using a flow channel to solve product jetting patterns according to claim 2, characterized in that, The mold flow channel cavity is a two-cavity mold. The primary flow channel (3) is symmetrically installed below the main flow channel (1), the secondary flow channel (4) is symmetrically installed at one end of the primary flow channel (3), and the tertiary flow channel (5) is symmetrically installed at one end of the secondary flow channel (4).

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