A method for in-mold cutting of thick-walled multi-layer blow-molded tubes

Abstract

The present invention relates to the field of mold blow molding, and in particular to a method for in-mold cutting of thick-walled multi-layer blow-molded tubes. A method for in-mold cutting of thick-walled multi-layer blow-molded tubes, specifically comprising the following steps: S1: passing a molten blank into the mold cavities of an upper mold and a lower mold, controlling the blowing needle and the return air needle to be inserted into the two ends of the mold cavities; S2: blow-molding the multi-layer blow-molded tube to be cut inside the mold cavities of an upper mold and a lower mold, with a first blow needle dummy and a second blow needle dummy at both ends of the blow-molded tube blank. The method for in-mold cutting of thick-walled multi-layer blow-molded tubes provided by the present invention can conveniently and quickly cut the blank dummy, quickly cool the blank at the position where cutting is required, cool it to the most suitable temperature for cutting, and cut it at the moment the mold is opened. It can achieve rapid cutting of blow-molded tubes with a wall thickness of 1 to 7 mm. This method is highly efficient and does not require separate cutting tooling, thereby reducing production costs.

Description

Technical Field

[0001] The invention relates to the field of mold blow molding, in particular to a method for cutting a thick-walled multi-layer blow molding tube in a mold. Background Art

[0002] In order to ensure the reliability of the fuel filling system, the dummy heads at both ends of the finished blow-molded tube need to be cut during the processing of the blow-molded tube. The requirements for cutting the dummy heads of the blow-molded tube are high. Poor cutting will affect the next process and cause leakage. The middle layer of the multi-layer blow-molded tube has a barrier layer. The material hardness and strength of the barrier layer are better than those of the surface layer. The multi-layer blow-molded tube with thicker wall is prone to abnormal problems such as drawing, delamination, and deformation when the mold is opened and the mold is cut. Abnormal problems will affect the next process and even cause risks such as oil leakage due to poor assembly.

[0003] Therefore, it is necessary to provide a new method for cutting thick-walled multi-layer blow molding tubes in a mold to solve the above-mentioned technical problems. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a method for in-mold cutting of thick-walled multi-layer blow-molded tubes.

[0005] The present invention provides a method for in-mold cutting of thick-walled multi-layer blow-molded tubes, which comprises the following specific steps:

[0006] S1: The molten billet is passed into the mold cavities of the upper mold and the lower mold, and the air blowing needle and the air return needle are controlled to be inserted into the two ends of the mold cavity;

[0007] S2: blow-molding the multi-layer blow-molded tube to be cut in the mold cavities of the upper mold and the lower mold, with a first blow needle dummy and a second blow needle dummy at both ends of the blow-molded tube blank;

[0008] S3: The temperature and time of the cold air input by the blowing needle are used to control the temperature of the cutting position, so that the inner wall of the blow molding tube is cooled quickly;

[0009] S4: The first blow needle dummy head and the second blow needle dummy head are cut by a tool, and the cut semi-finished products are processed into the next step.

[0010] Preferably, a first cylinder is fixedly installed on one side of the lower mold, and the output end of the first cylinder is fixedly connected to the blowing needle, and the length of the blowing needle is controlled by the first cylinder.

[0011] Preferably, the lower mold adopts a mold insert structure outside the cutting portion of the blow molded product, and a cooling water channel is provided inside the mold insert for cooling.

[0012] Preferably, a second cylinder is fixedly installed on the top of the lower mold, and the output end of the second cylinder is fixedly connected to the tool, and the tool is controlled by the second cylinder.

[0013] Preferably, the second cylinder is independently designed with an external PLC program to control the propulsion speed and time of the second cylinder.

[0014] Preferably, room temperature air or cold air is passed into the insufflation needle.

[0015] Compared with the related art, the method for in-mold cutting of thick-walled multi-layer blow-molded tubes provided by the present invention has the following beneficial effects:

[0016] The present invention provides a method for in-mold cutting of thick-walled multi-layer blow-molded tubes. The method can conveniently and quickly cut a blank dummy head, quickly cool the blank at the position where cutting is required to the temperature most suitable for cutting, and cut the blank at the moment the mold is opened. A PLC program is used to independently control the speed and time of cylinder feeding to cope with multi-layer blow-molded tubes of different thicknesses. After cutting, the tool can seal the gas to allow the product to continue to maintain pressure and shape. After the mold is opened, the product can be directly removed by a robot arm and can directly enter the next step of the process, thereby saving separate cutting equipment and achieving very high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic structural diagram of the upper mold and lower mold provided by the present invention;

[0018] Figure 2 for Figure 1 The schematic structural diagram of the multi-layer blow molding tube shown;

[0019] Figure 3 A schematic structural diagram of a semi-finished product provided by the present invention;

[0020] Figure 4 This is a schematic flow chart of the method for in-mold cutting of thick-walled multi-layer blow-molded tubes provided by the present invention.

[0021] Numbers in the figure: 1. Multi-layer blow molding tube; 2. First blow needle dummy head; 3. Second blow needle dummy head; 4. Semi-finished product; 5. Blow needle; 6. Return air needle; 7. Tool; 8. Second cylinder; 9. Mold insert; 10. First cylinder; 11. Upper mold; 12. Lower mold. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0024] See also Figures 1 to 4, a method for in-mold cutting of thick-walled multi-layer blow-molded tubes, the specific steps are as follows:.

[0025] S1: The molten billet is passed into the mold cavities of the upper mold 11 and the lower mold 12, and the air blowing needle 5 and the air return needle 6 are controlled to be inserted into the two ends of the mold cavity;

[0026] S2: The multi-layer blow-molded tube 1 to be cut is blow-molded inside the mold cavity of the upper mold 11 and the lower mold 12, with the first blow needle dummy 2 and the second blow needle dummy 3 at both ends of the blow-molded tube blank;

[0027] S3: The temperature and time of the cold air inputted by the blowing needle 5 are used to control the temperature of the cutting position, so that the inner wall of the blow molding tube is cooled quickly;

[0028] S4: The first blow needle dummy head 2 and the second blow needle dummy head 3 are cut by the cutter 7, and the cut semi-finished product 4 is subjected to the next process.

[0029] In the embodiments of the present invention, see Figures 1 to 4 A first cylinder 10 is fixedly installed on one side of the lower mold 12 , and the output end of the first cylinder 10 is fixedly connected to the blowing needle 5 , and the length of the blowing needle 5 is controlled by the first cylinder 10 .

[0030] In the embodiments of the present invention, see Figures 1 to 4 The lower mold 12 adopts a mold insert 9 structure outside the cutting part of the blow molded product, and there is a cooling water channel inside the mold insert 9 for cooling.

[0031] In the embodiments of the present invention, see Figures 1 to 4 A second cylinder 8 is fixedly installed on the top of the lower mold 12, and the output end of the second cylinder 8 is fixedly connected to the tool 7, and the tool 7 is controlled by the second cylinder 8;

[0032] In the embodiments of the present invention, see Figures 1 to 4 , the second cylinder 8 is designed with a separate external PLC program to control the propulsion speed and time of the second cylinder 8;

[0033] In the embodiments of the present invention, see Figures 1 to 4 , let room temperature air or cold air into the inside of the blowing needle 5, and the blowing needle 5 can input cold air to quickly cool the inside of the cutting part.

[0034] The working principle of the method for in-mold cutting of thick-walled multi-layer blow-molded tubes provided by the present invention is as follows: first, a multi-layer blow-molded tube 1 to be cut is provided, and a first blow needle dummy head 2 and a second blow needle dummy head 3 are provided at both ends of the blow-molded tube blank. The first blow needle dummy head 2 and the second blow needle dummy head 3 need to be cut, and the semi-finished product 4 after cutting can proceed to the next step. A blowing needle 5 and a return air needle 6 are designed inside the mold. The length of the blowing needle 5 can be controlled by a first cylinder 10. The blowing needle 5 can be fed with gas at room temperature or with cold air. A tool 7 is designed at the position where cutting is required, and the tool 7 is controlled by a second cylinder 8. The cylinders are designed separately. The external PLC program can control the propulsion speed and time of the cylinder, and control the temperature of the cutting position by controlling the temperature and time of the cold air input by the blowing needle 5, so that the inner wall of the blow molded tube is quickly cooled to 70-90°. The outer wall of the blow molded tube cutting position is designed with a mold insert 9, and cooling water is passed into the mold insert 9. By controlling the water temperature of the cooling water, the outer wall of the blow molded tube cutting position is quickly cooled to 70-90°. After the cutting position is fully cooled, the flatness of the tool cutting is very good, and the blow molded tube with a wall thickness of 1-7 mm can be quickly cut. This method is highly efficient and does not require separate cutting tooling, thereby reducing production costs.

[0035] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for in-mold cutting of thick-walled multi-layer blow-molded tubes, characterized in that: The specific steps are as follows: S1: The molten blank is passed into the mold cavities of the upper mold (11) and the lower mold (12), and the air blowing needle (5) and the air return needle (6) are controlled to be inserted into the two ends of the mold cavity; S2: blow-molding the multi-layer blow-molded tube (1) to be cut inside the mold cavity of the upper mold (11) and the lower mold (12), with a first blow needle dummy head (2) and a second blow needle dummy head (3) at both ends of the blow-molded tube blank; S3: The temperature and time of the cold air inputted through the blowing needle (5) are used to control the temperature of the cutting position, so that the inner wall of the blow molding tube is cooled quickly; S4: cutting the first blow needle dummy head (2) and the second blow needle dummy head (3) by a cutter (7), and the cut semi-finished product (4) is subjected to the next step; A first cylinder (10) is fixedly mounted on one side of the lower mold (12), and an output end of the first cylinder (10) is fixedly connected to the blowing needle (5), and the length of the blowing needle (5) is controlled by the first cylinder (10); The lower mold (12) adopts a mold insert (9) structure outside the cutting part of the blow molded product, and a cooling water channel is provided inside the mold insert (9) for cooling; A second cylinder (8) is fixedly mounted on the top of the lower mold (12), and an output end of the second cylinder (8) is fixedly connected to the tool (7), and the tool (7) is controlled by the second cylinder (8); The second cylinder (8) is independently designed with an external PLC program to control the propulsion speed and time of the second cylinder (8); Let room temperature air or cold air flow into the blowing needle (5).

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