Special injection molding machine for PET (Polyethylene Terephthalate) bottle preform

Abstract

The invention relates to the field of injection molding, in particular to a special injection molding machine for PET bottle preforms, which comprises a mounting bracket, a sliding rod, an upper template, a hydraulic push rod, a lower template and the like, a plurality of sliding rods are mounted on the mounting bracket; all the sliding rods are jointly connected with an upper die plate in a sliding mode. A plurality of hydraulic push rods are mounted on the mounting bracket; the telescopic ends of all the hydraulic push rods are fixedly connected with the upper template together; and a lower template is mounted on the mounting bracket. The first lower mold and the second lower mold form PET bottle blanks of different sizes, and the same upper mold, namely the upper mold plate and the upper mold, of the equipment can be achieved by replacing different upper molds by detaching the upper mold plate, so that the forming problem of the PET bottle blanks of different sizes is solved, and the problem that time and labor are wasted during mold replacement is solved.

Description

Technical Field

[0001] The present invention relates to the field of injection molding, and in particular to an injection molding machine dedicated to PET preforms. Background Art

[0002] Most of the existing molds are integrally cast. That is, after a period of use, due to certain wear during the use of the mold, but the PET preform mold is composed of multiple cavities, and during the use process, often only one or multiple cavities are worn. However, during normal production, it will not affect the molding work of other cavities. And during the production of PET preforms, not only when the cavities of the mold are worn or damaged, but also when facing preforms of different sizes, the mold needs to be replaced. However, since most of the existing molds are integrally cast, that is, the whole mold needs to be replaced, which is not only time-consuming but also laborious. Summary of the Invention

[0003] In order to overcome the disadvantages mentioned in the background art, the present invention provides an injection molding machine dedicated to PET preforms.

[0004] The technical solution is as follows: An injection molding machine dedicated to PET preforms includes an installation bracket, sliding rods, an upper template, hydraulic push rods, and a lower template; several sliding rods are installed on the installation bracket; the upper template is slidably connected to all the sliding rods; several hydraulic push rods are installed on the installation bracket; the telescopic ends of all the hydraulic push rods are fixedly connected to the upper template; the lower template is installed on the installation bracket; it also includes an upper mold, fasteners, and a first lower mold; several fasteners are fixedly connected to the upper template; an upper mold is screwed onto each fastener; several first lower molds are fixedly connected to the lower template.

[0005] Optionally, the upper template is composed of two plates combined and fixedly connected.

[0006] Optionally, it further includes an adjustment assembly, and the adjustment assembly includes an installation frame, an electric push rod, a first connecting plate, a first connecting rod, an injection pipe, and a second lower mold; the installation frame is fixedly connected to the installation bracket; the installation frame is fixedly connected to the lower template; several electric push rods are fixedly connected to the installation frame; the telescopic ends of all the electric push rods are fixedly connected to the first connecting plate; several first connecting rods are fixedly connected to the first connecting plate; a second lower mold is connected to each first connecting rod; an injection pipe is passed through each first connecting rod; all the injection pipes are fixedly connected to the first connecting plate; each first connecting plate is communicated with the second lower mold.

[0007] Optionally, a temperature control component is also included, which includes a second connecting plate, a second connecting rod, an elastic member, a heating tube and a connecting pipe; a second connecting plate is fixedly connected to the inside of the mounting bracket; a plurality of second connecting rods are slidably connected to the second connecting plate; each second connecting rod is fixedly connected to an elastic member; the other ends of all the elastic members are fixedly connected to the second connecting plate; a plurality of adjacent second connecting rods are commonly fixedly connected to a heating tube; the heating tube is slidably connected to the lower mold plate; and each heating tube is in contact with the corresponding first lower mold.

[0008] Optionally, a plurality of groups of first through holes are provided on the upper template, and the first through holes are arranged in an inclined state.

[0009] Optionally, each first lower mold is provided with a plurality of second through holes.

[0010] Optionally, a plurality of third through holes are formed on the first connecting plate.

[0011] Optionally, a plurality of fourth through holes are formed on each heating cylinder.

[0012] The beneficial effects of the present invention are as follows: 1. The present invention forms PET preforms of different sizes through the first lower mold and the second lower mold. The upper mold of the same device, that is, the upper mold plate and the upper mold, can be replaced with different upper molds by disassembling the upper mold plate to solve the molding problem of PET preforms of different sizes and reduce the troublesome and laborious problem of mold replacement. In the production process, the injection molding tube is connected with the external injection molding equipment to perform injection molding. In the process of use, the above-mentioned method of adjusting the size of the lower mold is not only used for adjustment. After the PET preform is formed, the hydraulic push rod and the electric push rod are controlled to shrink synchronously, the hydraulic push rod drives the upper mold to move upward, the electric push rod drives the second lower mold to slide in the first lower mold, and the PET preform after the molding moves upward, so that the PET preform is separated from the first lower mold, which is convenient for demolding the PET preform and avoids damage to the PET preform during manual demolding.

[0013] 2. The present invention sprays cold air through the first through hole, that is, the cold air is in direct contact with the formed PET preform, thereby further reducing the temperature of the PET preform, making it easier for workers to take out samples of the PET preform and reducing the risk of workers being scalded by the residual temperature of the PET preform. The directly spraying cold air can quickly cool the demolded PET preform. It should be noted that the temperature of the preform during demolding is approximately between degrees and degrees, and this temperature range ensures that the PET preform is hard enough to prevent deformation and also saves a lot of time for subsequent cooling of the PET preform. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of a special injection molding machine for PET bottle preforms of the present invention;

[0015] Figure 2 It is a schematic diagram of the combined structure of the upper template, hydraulic push rod, upper mold and fasteners on the special injection molding machine for PET preforms of the present invention;

[0016] Figure 3 It is a schematic diagram of the combined structure of the lower template and the first lower mold on the special injection molding machine for PET preforms of the present invention;

[0017] Figure 4 It is a schematic diagram of the combined structure of the electric push rod, the first connecting plate and the first connecting rod on the special injection molding machine for PET preforms of the present invention;

[0018] Figure 5 It is a schematic diagram of the combined structure of the first connecting rod, the injection molding pipe and the second lower mold on the special injection molding machine for PET preforms of the present invention;

[0019] Figure 6 It is a schematic diagram of the combined structure of the second connecting rod and the elastic member on the special injection molding machine for PET preforms of the present invention;

[0020] Figure 7 It is a schematic diagram of the combined structure of the elastic member and the heating cylinder on the special injection molding machine for PET preforms of the present invention;

[0021] Figure 8 It is a schematic diagram of the combined structure of the first lower mold and the heating cylinder on the special injection molding machine for PET preforms of the present invention;

[0022] Figure 9 It is a schematic diagram of the combined structure of the upper template and the connecting pipe on the special injection molding machine for PET preforms of the present invention;

[0023] Figure 10 It is a schematic diagram of the structure of the first connecting plate on the special injection molding machine for PET preforms of the present invention.

[0024] Marks in the drawings: 1 - mounting bracket, 2 - sliding rod, 3 - upper template, 3001 - first through hole, 4 - hydraulic push rod, 5 - upper mold, 6 - fastener, 7 - lower template, 8 - first lower mold, 8001 - second through hole, 101 - mounting frame, 102 - electric push rod, 103 - first connecting plate, 10301 - third through hole, 104 - first connecting rod, 105 - injection molding pipe, 106 - second lower mold, 201 - second connecting plate, 202 - second connecting rod, 203 - elastic member, 204 - heating cylinder, 20401 - fourth through hole, 205 - connecting pipe. Detailed implementation manners

[0025] The following is only a preferred embodiment of the present invention, and it does not limit the protection scope of the present invention accordingly.

[0026] Embodiment 1

[0027] An injection molding machine dedicated to PET preforms, as Figures 1 - 3 shown, includes a mounting bracket 1, slide bars 2, an upper template 3, hydraulic push rods 4 and a lower template 7; Four slide bars 2 distributed in a rectangle are installed on the mounting bracket 1; The upper template 3 is slidably connected to all the slide bars 2 together; Two symmetrically arranged hydraulic push rods 4 are installed on the mounting bracket 1; The telescopic ends of all the hydraulic push rods 4 are fixedly connected to the upper template 3 together; The lower template 7 is installed on the mounting bracket 1;

[0028] It also includes an upper mold 5, fasteners 6 and a first lower mold 8; Thirty-five fasteners 6 distributed in a rectangle are fixedly connected to the upper template 3; The upper mold 5 is screwed onto each fastener 6; Thirty-five first lower molds 8 distributed in a rectangle are bolted to the lower template 7.

[0029] The upper template 3 is composed of two plates and is bolted together for easy overall disassembly and replacement.

[0030] First, the staff selects different first lower molds 8 according to the size of the PET preforms to be produced, then installs the first lower mold 8 on the lower template 7 using bolts. Then, the corresponding upper mold 5 is selected, and then the upper mold 5 is screwed onto the fastener 6 to fix the upper mold 5. Then, the staff connects the external injection molding equipment to the injection port of the first lower mold 8. Then, the hydraulic push rod 4 is controlled to push the upper template 3 downward, that is, to drive the upper template 3 to move downward and fit the lower template 7. At the same time, the upper template 3 drives the upper mold 5 and the fastener 6 to move downward and approach the first lower mold 8, that is, to drive the upper mold 5 into the first lower mold 8, thus completing the mold assembly. Then, the heating equipment built into the lower template 7 is controlled to heat the first lower mold 8. Then, the external injection molding equipment is controlled to operate to inject PET raw materials into the upper mold 5 and the first lower mold 8. Then, wait for the PET raw materials to cool, or cool the first lower mold 8 through the built-in temperature control equipment. After the PET raw materials are cooled and shaped, the injection molding of the PET preforms is completed. Then, the hydraulic push rod 4 is controlled to contract to drive the upper template 3, the upper mold 5 and the fastener 6 to move upward, that is, to drive the upper mold 5 to disengage from the first lower mold 8. Then, the staff takes out the formed PET preforms from the first lower mold 8. It should be noted that most of the existing molds are integrally cast. That is, after a period of use, due to certain wear during the use of the molds, but the PET preform mold is composed of multiple cavities, and during the use process, often one or multiple cavities are worn, but during normal production, it will not affect the forming work of other cavities. However, because most of the existing molds are integrally cast, that is, the whole needs to be replaced. The overall replacement is not only time-consuming and laborious, and at the same time, the injection molding equipment also needs to keep heating the PET raw materials to keep the PET raw materials in a molten state. But in this equipment, the upper mold 5 and the first lower mold 8 at the corresponding positions can be replaced in time according to the state of the formed PET preforms.

[0031] Embodiment 2

[0032] Based on the above Embodiment 1, as Figures 3 - 5As shown, it also includes an adjustment component, which includes a mounting frame 101, an electric push rod 102, a first connecting plate 103, a first connecting rod 104, an injection molding tube 105 and a second lower mold 106; the mounting frame 101 is fixedly connected to the mounting bracket 1; the mounting frame 101 is fixedly connected to the lower mold plate 7; eight electric push rods 102 distributed in a rectangular shape are fixedly connected to the mounting frame 101; the telescopic ends of all the electric push rods 102 are fixedly connected to the first connecting plate 103; thirty-five first connecting rods 104 distributed in a rectangular shape are fixedly connected to the first connecting plate 103; each first connecting rod 104 is connected to the second lower mold 106; each first connecting rod 104 is penetrated by an injection molding tube 105; all the injection molding tubes 105 are fixedly connected to the first connecting plate 103; each first connecting plate 103 is connected to the second lower mold 106.

[0033] In the process of producing PET preforms, the mold needs to be replaced not only when the mold cavity is worn or damaged, but also when facing preforms of different sizes, the mold needs to be replaced, especially the lower mold. However, in the present device, replacing the lower mold requires individual disassembly, which wastes a lot of time. In order to solve this problem, the present device adopts a method of forming a lower mold by a first lower mold 8 and a second lower mold 106, and adjusts the lower mold by the cooperation of an electric push rod 102, a first connecting plate 103 and a first connecting rod 104, that is, the electric push rod 102 is controlled to extend and retract to drive the first connecting plate 103, the first connecting rod 104 and the second lower mold 106 to slide in the first lower mold 8, and PET preforms of different sizes are formed by the first lower mold 8 and the second lower mold 106. Similarly, the upper mold of the present device , that is, the upper template 3 and the upper mold 5, the upper mold 5 can be replaced by removing the upper template 3 to solve the molding problem of PET preforms of different sizes and reduce the troublesome and laborious problem of mold replacement. In the production process, it is connected with the external injection molding equipment through the injection tube 105 to perform injection molding. In the process of use, the above-mentioned method of adjusting the size of the lower mold is not only used for adjustment. After the PET preform is formed, the hydraulic push rod 4 and the electric push rod 102 are controlled to shrink synchronously, the hydraulic push rod 4 drives the upper mold 5 to move upward, and the electric push rod 102 drives the second lower mold 106 to slide in the first lower mold 8, and the formed PET preform moves upward, so that the PET preform is separated from the first lower mold 8, which is convenient for the demolding of the PET preform and avoids damage to the PET preform during manual demolding.

[0034] Example 3

[0035] Based on the above embodiment 2, Figures 6 - 10As shown in the figure, it further includes a temperature control component, which includes a second connecting plate 201, a second connecting rod 202, an elastic member 203, a heating cylinder 204 and a connecting pipe 205; the second connecting plate 201 is fixedly connected inside the mounting bracket 1; seventy second connecting rods 202 distributed in a rectangular shape are slidably connected to the second connecting plate 201; an elastic member 203 is fixedly connected to each second connecting rod 202; the other ends of all the elastic members 203 are fixedly connected to the second connecting plate 201; two adjacent second connecting rods 202 are jointly fixedly connected to a heating cylinder 204; the heating cylinder 204 is slidably connected to the lower template 7; each heating cylinder 204 is in contact with the corresponding first lower mold 8.

[0036] A number of groups of thirty-five first through holes 3001 distributed in a rectangular shape are formed in the upper template 3, and the first through holes 3001 are arranged in an inclined state for conveying cold air and directly reducing the temperature of the PET preform.

[0037] Four second through holes 8001 arranged in an annular array are formed in each first lower mold 8 for conveying cold air.

[0038] Seventy third through holes 10301 distributed in a rectangular shape are formed in the first connecting plate 103 for discharging cold air in cooperation.

[0039] Two symmetrically arranged fourth through holes 20401 are formed in each heating cylinder 204 for discharging cold air in cooperation.

[0040] First, the staff uses a cooling device to communicate with the connecting pipe 205. Before injection molding, the first lower mold 8 needs to be preheated so that the PET raw material in a molten state can flow better in the cavity of the mold to ensure uniform filling of the entire cavity. After injection molding, it is necessary to carry out a cooling operation to quickly reduce the temperature by cooling, thereby accelerating the forming speed of the PET preform. That is, during this process, the externally provided cooling device is controlled to convey cold air into the connecting pipe 205. That is, the cold air enters the third through hole 10301 through the connecting pipe 205. Since the upper template 3 and the lower template 7 are in a fitting state at this time, that is, the third through hole 10301 and the second through hole 8001 are in a communicating state, so the cold air enters the second through hole 8001 through the third through hole 10301. Since the second through holes 8001 are in an interlaced state, that is, during this process, the cold air ejected from the second through holes 8001 pushes the heating cylinder 204, causing the heating cylinder 204 to slide downward in the first lower mold 8. Since there are four second through holes 8001 provided on each second through hole 8001, and only two fourth through holes 20401 are provided on each heating cylinder 204, and the diameters of the second through holes 8001 and the fourth through holes 20401 are the same, the heating cylinder 204 will slide downward in the first lower mold 8 at a uniform speed until the heating cylinder 204 contacts the first connecting plate 103. At the same time, the downward movement of the heating cylinder 204 pushes the second connecting rod 202 downward and stretches the elastic member 203, so that the fourth through hole 20401 communicates with the third through hole 10301 and discharges the cold air. It should be noted that in the prior art, the mold heating and cooling both use the same temperature controller and need to continuously adjust the temperature, that is, it is necessary to convert from high temperature to low temperature and then from low temperature to high temperature, and so on. This not only requires a lot of time, but also during the conversion process between high and low temperatures, the internal components are damaged at an accelerated speed. The above method cools down by injecting circulating cold air, which can not only improve the efficiency, but also at the same time, the heating cylinder 204 part also remains working to heat the injection pipe 105 to prevent the PET raw material in the injection pipe 105 from cooling and causing blockage during the cooling process. It should be noted that the existing injection molding equipment is often affected by blockage at the injection port, and the problem of condensation and blockage of the injection pipe 105 is the most obvious. That is, through the above method, heating work is carried out on the parts that need to be heated, and cooling work is carried out on the parts that need to be cooled, and they do not affect each other, which is beneficial to the forming of the PET preform. And after the formed PET preform is ejected, since the first through hole 3001 is arranged to incline inward, that is, cold air is ejected through the first through hole 3001, that is, the cold air directly contacts the formed PET preform, further reducing the temperature of the PET preform, facilitating the staff to take out the sample of the PET preform, reducing the risk of the staff being scalded by the residual temperature of the PET preform, and the method of directly ejecting cold air can quickly cool down the PET preform after demolding. It should be noted that the temperature of the preform during demolding is approximately between degrees and degrees, and this temperature range,It not only ensures that the PET preforms are hard enough to prevent deformation, but also saves a large amount of time for the subsequent cooling of the PET preforms.

[0041] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A special injection molding machine for PET preforms, comprising a mounting bracket (1), a slide bar (2), an upper template (3), a hydraulic push rod (4) and a lower template (7); a plurality of slide bars (2) are mounted on the mounting bracket (1); the upper template (3) is slidably connected to all the slide bars (2); a plurality of hydraulic push rods (4) are mounted on the mounting bracket (1); the telescopic ends of all the hydraulic push rods (4) are fixedly connected to the upper template (3); the lower template (7) is mounted on the mounting bracket (1); the characteristics are that: It also includes an upper mold (5), a fastener (6) and a first lower mold (8); a plurality of fasteners (6) are fixedly connected to the upper mold plate (3); an upper mold (5) is screwed onto each fastener (6); and a plurality of first lower molds (8) are fixedly connected to the lower mold plate (7).

2. The PET preform injection molding machine according to claim 1, characterized in that: The upper template (3) is composed of two plates which are fixedly connected.

3. The PET preform injection molding machine according to claim 2, characterized in that: The invention also comprises an adjustment component, which comprises a mounting frame (101), an electric push rod (102), a first connecting plate (103), a first connecting rod (104), an injection molding tube (105) and a second lower mold (106); the mounting frame (101) is fixedly connected to the mounting bracket (1); the mounting frame (101) is fixedly connected to the lower mold plate (7); a plurality of electric push rods (102) are fixedly connected to the mounting frame (101); the telescopic ends of all the electric push rods (102) are fixedly connected to the first connecting plate (103); a plurality of first connecting rods (104) are fixedly connected to the first connecting plate (103); each first connecting rod (104) is connected to the second lower mold (106); an injection molding tube (105) is passed through each first connecting rod (104); all the injection molding tubes (105) are fixedly connected to the first connecting plate (103); and each first connecting plate (103) is connected to the second lower mold (106).

4. The PET preform injection molding machine according to claim 3, characterized in that: It also includes a temperature control component, which includes a second connecting plate (201), a second connecting rod (202), an elastic member (203), a heating tube (204) and a connecting pipe (205); the second connecting plate (201) is fixedly connected inside the mounting bracket (1); a plurality of second connecting rods (202) are slidably connected to the second connecting plate (201); each second connecting rod (202) is fixedly connected to the elastic member (203); the other ends of all the elastic members (203) are fixedly connected to the second connecting plate (201); a plurality of adjacent second connecting rods (202) are commonly fixedly connected to the heating tube (204); the heating tube (204) is slidably connected to the lower mold plate (7); and each heating tube (204) is in contact with the corresponding first lower mold (8).

5. The PET preform injection molding machine according to claim 1, characterized in that: The upper template (3) is provided with a plurality of groups of first through holes (3001), and the first through holes (3001) are arranged in an inclined state.

6. The PET preform injection molding machine according to claim 1, characterized in that: Each first lower mold (8) is provided with a plurality of second through holes (8001).

7. The PET preform injection molding machine according to claim 1, characterized in that: A plurality of third through holes (10301) are provided on the first connecting plate (103).

8. The PET preform injection molding machine according to claim 1, characterized in that: A plurality of fourth through holes (20401) are provided on each heating cylinder (204).

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