Injection mold for forming aluminum-plastic composite pipe

Abstract

The invention discloses an injection mold for aluminum-plastic composite pipe forming, and relates to the technical field of pipe forming, the injection mold comprises a machine head body, an outer opening mold, a first core rod and a second core rod, the outer opening mold is arranged on one side of the machine head body, the second core rod is arranged in the machine head body and the outer opening mold in a penetrating mode in the preset direction, and the first core rod is arranged in the second core rod in a penetrating mode in the preset direction; a gap is formed between the first core rod and the second core rod so as to form a first drainage cavity for conveying liquid glue, and gaps are formed between the second core rod and the machine head body and between the second core rod and the outer opening mold so as to form a second drainage cavity for conveying molten plastic; the aluminum-plastic composite pipe has the beneficial effects that the aluminum pipe is coated with the molten plastic after being coated with the glue, and the glue can be prevented from being cooled and solidified in the conveying process, so that the bonding performance between the inner layer of the aluminum pipe and the outer layer of the plastic after the aluminum-plastic composite pipe is formed is improved, and the stripping rate between the inner layer of the aluminum pipe and the outer layer of the plastic is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe forming, and particularly relates to an injection mold for forming an aluminum-plastic composite pipe. Background Art

[0002] The aluminum-plastic composite pipe is a new type of practical pipe developed on the basis of traditional plastic pipes. It combines the physical and chemical advantages of two materials, metal and plastic. As a water supply pipe, the aluminum-plastic composite pipe has sufficient strength and high-temperature pressure resistance.

[0003] Currently, when the aluminum-plastic composite pipe is produced and formed, usually the aluminum strip is first processed into the inner layer of the aluminum pipe, then a layer of molten adhesive is coated on the surface of the inner layer of the aluminum pipe through a coating machine, and finally the inner layer of the aluminum pipe is transported to an injection molding machine. The injection molding machine then extrudes the molten plastic onto the surface of the inner layer of the aluminum pipe, so that the molten plastic forms a plastic outer layer after cooling.

[0004] However, the following defects exist in the prior art: During the transportation of the aluminum pipe coated with adhesive to the injection molding machine, several transfer processes are required, and the adhesive will cool and solidify to a certain extent during transportation, thus affecting the bonding performance between the inner layer of the aluminum pipe and the plastic outer layer. Specifically, the inner wall of part of the plastic outer layer will be peeled off from the aluminum pipe (i.e., there is a middle gap between the two), and further, the bearing performance of the aluminum-plastic composite pipe after forming is poor, the external pressure resistance strength is small, and it cannot meet the use requirements, thereby reducing the excellent product rate of the aluminum-plastic composite pipe. Summary of the Invention

[0005] The purpose of the present invention is to provide an injection mold for forming an aluminum-plastic composite pipe to solve the problems pointed out in the above background art. The present invention is realized through the following technical solutions.

[0006] An injection mold for forming an aluminum-plastic composite pipe includes a head body, an outer die, a first mandrel, and a second mandrel. The outer die is arranged on one side of the head body. The second mandrel penetrates through the head body and the outer die along a preset direction. The first mandrel penetrates through the second mandrel along the preset direction, and there is a gap between the first mandrel and the second mandrel to form a first drainage chamber for transporting liquid glue. There are gaps between the second mandrel and the head body and between the second mandrel and the outer die to form a second drainage chamber for transporting molten plastic. Among them, the first mandrel is provided with a penetration chamber for the aluminum tube to penetrate into. The first mandrel is provided with a first penetration opening, the second mandrel is provided with a second penetration opening, and the outer die is provided with a third penetration opening. The first drainage chamber extends between the first penetration opening and the second penetration opening, and the second drainage chamber extends between the second penetration opening and the third penetration opening. The first penetration opening, the second penetration opening, and the third penetration opening are used for the aluminum tube to penetrate out in sequence.

[0007] As a further improvement of the present invention, the diameter of the second penetration opening is larger than that of the first penetration opening, and the diameter of the third penetration opening is larger than that of the second penetration opening.

[0008] As a further improvement of the present invention, the first mandrel sequentially includes a first connection part, a first gap part, and a first tapered end part along the material feeding direction. Among them, the outer wall of the first connection part is closely attached to the inner wall of the second mandrel, and the first drainage chamber is formed between the second mandrel, the first gap part, and the first tapered end part.

[0009] As a further improvement of the present invention, the distance between the first tapered end part and the inner wall of the second mandrel gradually decreases.

[0010] As a further improvement of the present invention, the second mandrel sequentially includes a second connection part, a second gap part, and a second tapered end part along the material feeding direction. Among them, the outer wall of the second connection part is closely attached to the inner wall of the machine head body, and the second drainage chamber is formed between the machine head body, the second gap part, and between the outer die and the second tapered end part.

[0011] As a further improvement of the present invention, the inner cavity of the outer die is a tapered inner cavity, and the distance between the second tapered end part and the inner wall of the outer die gradually decreases.

[0012] As a further improvement of the present invention, a glue channel is provided on the side wall of the machine head body, and an intermediate channel is provided on the side wall of the second mandrel. Both ends of the intermediate channel are respectively communicated with the glue channel and the first drainage chamber.

[0013] As a further improvement of the present invention, a molten plastic channel is provided on the side wall of the machine head body, and the molten plastic channel is communicated with the second drainage chamber.

[0014] As a further improvement of the present invention, a collection groove is arranged around the outer wall of the second gap part.

[0015] As a further improvement of the present invention, at least one confluence step is provided on the first tapered end part.

[0016] Advantages of the present invention: In the mold of the present invention, a first mandrel and a second mandrel are provided for an aluminum tube to pass through in sequence. Specifically, during the production process, the aluminum tube first penetrates into the penetration chamber, and then sequentially passes through the first penetration opening, the second penetration opening, and the third penetration opening, so that a layer of liquid glue can be coated on the surface of the aluminum tube when passing between the first penetration opening and the second penetration opening. After that, it penetrates between the second penetration opening and the third penetration opening to coat molten plastic; finally, it is transported to the next process for cooling and shaping, that is, it is formed into an aluminum-plastic composite tube. Through the above settings, the present invention can save the transportation process between the glue coating process and the plastic outer layer coating process, thereby improving production efficiency. At the same time, since the molten plastic is coated immediately after the glue is coated on the aluminum tube, the glue can be prevented from cooling and solidifying during transportation, thereby improving the bonding performance between the inner layer of the aluminum tube and the plastic outer layer after the aluminum-plastic composite tube is formed, reducing the peeling rate between the inner layer of the aluminum tube and the plastic outer layer, and further improving the excellent product rate of the aluminum-plastic composite tube. Brief Description of the Drawings

[0017] The following will describe in detail the preferred embodiments of the present invention with the help of drawings to facilitate understanding of the purpose and advantages of the present invention, where: Figure 1 is a schematic structural diagram of an embodiment of the present invention; Figure 2 is a schematic internal structure diagram of an embodiment of the present invention; Figure 3 corresponding to an embodiment of the present invention Figure 2 is a partial enlarged view of part A in the figure; Figure 4 is a schematic structural diagram when the aluminum tube penetrates out in an embodiment of the present invention.

[0018] Reference numerals in the figure: head body 1, outer die 2, first mandrel 3, second mandrel 4, outer die sleeve 5, first drainage chamber 6, second drainage chamber 7, glue channel 8, molten plastic channel 9, penetration chamber 10, first penetration opening 11, second penetration opening 12, third penetration opening 13, first connection part 301, first gap part 302, first tapered end part 303, confluence step 304, second connection part 401, second gap part 402, second tapered end part 403. Detailed Description of the Specific Embodiment

[0019] The following further describes the present invention in detail according to the drawings and embodiments.

[0020] In this specification, the orientation terms such as up, down, left, right, front, back, front side, back side, top, bottom, etc., which are mentioned or may be mentioned, are defined with respect to the structures shown in the respective drawings. The terms "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component. They are relative concepts and may therefore change accordingly depending on their different positions and usage states. Therefore, these or other orientation terms should not be construed as restrictive terms.

[0021] Reference Figures 1 to 4 , what is disclosed in the embodiments of the present invention is: An injection mold for the forming of an aluminum-plastic composite pipe, comprising a head body 1, an outer die 2, an outer die sleeve 5, a first mandrel 3, and a second mandrel 4. The outer die 2 is fixedly arranged on one side of the head body 1 through the outer die sleeve 5. The second mandrel 4 is disposed through the head body 1 and the outer die 2 in a preset direction. The first mandrel 3 is disposed through the second mandrel 4 in a preset direction, and there is a gap between the first mandrel 3 and the second mandrel 4 to form a first drainage chamber 6 for conveying liquid glue (such as hot melt glue, which reaches a molten state after heating and becomes solid when cooled to room temperature under normal pressure). There are gaps between the second mandrel 4 and the head body 1 and between the second mandrel 4 and the outer die 2 to form a second drainage chamber 7 for conveying molten plastic. A glue channel 8 is provided on the side wall of the head body 1, and an intermediate channel is provided on the side wall of the second mandrel 4. Both ends of the intermediate channel are respectively communicated with the glue channel 8 and the first drainage chamber 6. A molten plastic channel 9 is provided on the side wall of the head body 1, and the molten plastic channel 9 is communicated with the second drainage chamber 7. Among them, the glue channel 8 is used to connect the output end of an external glue injector for inputting liquid glue, and the molten plastic channel 9 is used to connect an external injection molding machine for inputting molten plastic.

[0022] Among them, the first mandrel 3 is provided with a penetration chamber 10 for an aluminum tube to penetrate into. The first mandrel 3 is provided with a drainage chamber with a first through-opening 11. The second mandrel 4 is provided with a second through-opening 12, and the outer die 2 is provided with a third through-opening 13. The first drainage chamber 6 extends between the first through-opening 11 and the second through-opening 12, and the second drainage chamber 7 extends between the second through-opening 12 and the third through-opening 13. The first through-opening 11, the second through-opening 12, and the third through-opening 13 are for the aluminum tube to pass through in sequence. In the specific implementation process, a plastic support seat (not shown in the figure) is further arranged in the penetration chamber 10. The plastic support seat can allow the aluminum tube to pass through for supporting the aluminum tube. At the same time, the plastic support seat can seal the penetration chamber 10 to prevent the liquid glue from leaking from the penetration chamber 10. During the production process, the aluminum tube first penetrates into the penetration chamber 10, and then passes through the first through-opening 11, the second through-opening 12, and the third through-opening 13 in sequence, so that a layer of liquid glue can be coated on the surface of the aluminum tube when passing between the first through-opening 11 and the second through-opening 12. After that, it can penetrate between the second through-opening 12 and the third through-opening 13 to coat molten plastic, and finally be transported to the next process for cooling and shaping, that is, formed into an aluminum-plastic composite pipe. Through the above settings, the mechanism can save the transportation process between the glue coating process and the plastic outer layer coating process, thereby improving the production efficiency. At the same time, since the molten plastic is coated after the glue is coated on the aluminum tube, it can avoid the glue from cooling and solidifying during transportation, thereby improving the bonding performance between the inner layer of the aluminum tube and the plastic outer layer after the aluminum-plastic composite pipe is formed, reducing the peeling rate between the inner layer of the aluminum tube and the plastic outer layer, and further improving the excellent product rate of the aluminum-plastic composite pipe.

[0023] Specifically in this embodiment, the diameters (inner diameters) of the first through-opening 11, the second through-opening 12, and the third through-opening 13 increase in sequence. Among them, the inner diameter of the first through-opening 11 is adapted to the outer diameter of the aluminum tube to prevent the liquid glue from leaking from the first through-opening 11 into the penetration chamber 10. The inner diameter of the second through-opening 12 is larger than that of the first through-opening 11, so that the glue coated on the surface of the aluminum tube can be transported together with the aluminum tube between the second through-opening 12 and the third through-opening 13. Similarly, the inner diameter of the third through-opening 13 is larger than that of the second through-opening 12, and the plastic outer layer coated on the surface of the aluminum tube can also pass through the third through-opening 13 and be transported to the subsequent process.

[0024] In this embodiment, the first mandrel 3 sequentially includes a first connecting portion 301, a first gap portion 302, and a first tapered end portion 303 along the material feeding direction. Among them, the outer wall of the first connecting portion 301 is in close fit with the inner wall of the second mandrel 4, which can prevent the leakage of liquid glue from the gap between the first mandrel 3 and the second mandrel 4. The first through-opening 11 is opened at one end of the first tapered end portion 303. The first drainage chamber 6 is formed between the second mandrel 4, the first gap portion 302, and the first tapered end portion 303. That is, when the liquid glue is input between the first mandrel 3 and the second mandrel 4, it first passes through the gap between the first gap portion 302 and the second mandrel 4, then passes through the gap between the first tapered end portion 303 and the second mandrel 4, and finally is conveyed between the first through-opening 11 and the second through-opening 12. In addition, in this embodiment, the first connecting portion 301 and the first gap portion 302 are integrally formed, and the first tapered end portion 303 and the first gap portion 302 are detachably connected by a thread, so that the first tapered end portion 303 can be replaced.

[0025] In this embodiment, the distance between the first tapered end portion 303 and the inner wall of the second mandrel 4 gradually decreases; at least one converging step 304 is provided on the first tapered end portion 303. Through the above settings, a certain amount of liquid glue can be collected in the first drainage chamber 6 and then conveyed between the first through-opening 11 and the second through-opening 12, so that the liquid glue can be evenly coated on the surface of the aluminum tube.

[0026] The second mandrel 4 sequentially includes a second connecting portion 401, a second gap portion 402, and a second tapered end portion 403 along the material feeding direction. Among them, the second through-opening is opened at one end of the second tapered end portion 403. The outer wall of the second connecting portion 401 is in close fit with the inner wall of the machine head body 1, which can prevent the leakage of molten plastic from the gap between the outer wall of the second connecting portion 401 and the machine head body 1. The second drainage chamber 7 is formed between the machine head body 1, the second gap portion 402, and between the outer die 2 and the second tapered end portion 403. That is, during the input process of the molten plastic, it first passes through the gap between the machine head body 1 and the first gap portion 302, then passes through the gap between the outer die 2 and the second tapered end, and finally is conveyed to the second through-opening 12 and the third through-opening 13. In addition, in this embodiment, the second connecting portion 401 and the second gap portion 402 are integrally formed, and the second tapered end portion 403 and the second gap portion 402 are detachably connected by a thread, so that the second tapered end portion 403 can be replaced.

[0027] In this embodiment, the inner cavity of the outer die 2 is a conical inner cavity, and the distance between the second conical end head 403 and the inner wall of the outer die 2 gradually decreases; a collecting groove is arranged around the outer wall of the second gap portion 402 for confluence. Through the above settings, after a certain amount of molten plastic is collected between the second conical end head 403 and the inner wall of the outer die 2, the molten plastic is then conveyed between the second through-opening 12 and the third through-opening 13, so that the molten plastic can be evenly coated on the surface of the aluminum tube.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An injection mold for forming an aluminum-plastic composite pipe, characterized in that: The invention comprises a machine head body (1), an outer die (2), a first core rod (3), and a second core rod (4), wherein the outer die (2) is arranged on one side of the machine head body (1), the second core rod (4) is inserted into the machine head body (1) and the outer die (2) along a preset direction, the first core rod (3) is inserted into the second core rod (4) along a preset direction, and a gap is provided between the first core rod (3) and the second core rod (4) to form a first drainage chamber (6) for conveying liquid glue, and a gap is provided between the second core rod (4) and the machine head body (1) and the outer die (2) to form a second drainage chamber (7) for conveying molten plastic; The first mandrel (3) is provided with an entry chamber (10), and the entry chamber (10) is used for allowing the aluminum tube to pass through. The first mandrel (3) is provided with a first exit opening (11), and the second mandrel (4) is provided with a second exit opening (12). The outer die (2) is provided with a third exit opening (13). The first drainage chamber (6) extends between the first exit opening (11) and the second exit opening (12), and the second drainage chamber (7) extends between the second exit opening (12) and the third exit opening (13). The first exit opening (11), the second exit opening (12) and the third exit opening (13) are used for allowing the aluminum tube to pass through in sequence.

2. The injection mold for forming an aluminum-plastic composite pipe according to claim 1, characterized in that: The diameter of the second outlet opening (12) is greater than the diameter of the first outlet opening (11), and the diameter of the third outlet opening (13) is greater than the diameter of the second outlet opening (12).

3. The injection mold for forming an aluminum-plastic composite pipe according to claim 1, characterized in that: The first core rod (3) includes a first connecting portion (301), a first gap portion (302) and a first conical end portion (303) in sequence along the feeding direction, wherein the outer wall of the first connecting portion (301) is tightly fitted with the inner wall of the second core rod (4), and the first drainage chamber (6) is formed between the second core rod (4) and the first gap portion (302) and the first conical end portion (303).

4. The injection mold for forming an aluminum-plastic composite pipe according to claim 3, characterized in that: The distance between the first tapered end portion (303) and the inner wall of the second core rod (4) gradually decreases.

5. The injection mold for forming an aluminum-plastic composite pipe according to claim 1, characterized in that: The second core rod (4) includes a second connecting portion (401), a second gap portion (402) and a second conical end portion (403) in sequence along the feeding direction, wherein the outer wall of the second connecting portion (401) is tightly fitted with the inner wall of the machine head body (1), and the second drainage chamber (7) is formed between the machine head body (1) and the second gap portion (402), and between the outer die (2) and the second conical end portion (403).

6. The injection mold for forming an aluminum-plastic composite pipe according to claim 5, characterized in that: The inner cavity of the outer die (2) is a conical inner cavity, and the distance between the second conical end portion (403) and the inner wall of the outer die (2) gradually decreases.

7. The injection mold for forming an aluminum-plastic composite tube according to claim 1, characterized in that: The side wall of the machine head body (1) is provided with a glue channel (8), and the side wall of the second core rod (4) is provided with an intermediate channel, and the two ends of the intermediate channel are respectively connected to the glue channel (8) and the first drainage chamber (6).

8. The injection mold for forming an aluminum-plastic composite pipe according to claim 7, characterized in that: A molten plastic channel (9) is provided on the side wall of the machine head body (1), and the molten plastic channel (9) is communicated with the second drainage chamber (7).

9. The injection mold for forming an aluminum-plastic composite tube according to claim 5, characterized in that: A collecting groove is arranged around the outer wall of the second gap portion (402).

10. The injection mold for forming an aluminum-plastic composite tube according to claim 3, characterized in that: At least one converging step is provided on the first conical end portion (303).

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