Hollow blow molding machine and multi-layer electric control co-extrusion machine head thereof

Abstract

The invention discloses a hollow blow molding machine and a multilayer electric control co-extrusion machine head thereof, the hollow blow molding machine comprises a power mechanism, the output end of the power mechanism is connected with a core shaft, and the tail end of the core shaft is provided with a core mold; the outer wall of the power mechanism is fixedly provided with a three-layer runner assembly through a connecting piece, the three-layer runner assembly is provided with a feeding port, a plastic melt enters a spiral runner from the feeding port to be subjected to melt distribution and convergence to form a three-layer cylindrical parison, the output end of the three-layer runner assembly is communicated with a convergence cavity, and the output end of the three-layer runner assembly is communicated with the convergence cavity. A heating component is arranged outside the converging cavity; and a mouth mold matched with the core mold is arranged at the output end of the converging cavity. The servo motor is adopted to drive the core mold to move through the electric cylinder, a traditional hydraulic driving mode is changed, and parison control precision and repetition precision are improved by more than three times, so that wall thickness uniformity and weight consistency are guaranteed, and the electric control co-extrusion machine head is convenient to install and maintain, time-saving and labor-saving.

Description

Technical Field

[0001] This invention relates to the field of hollow plastic blow molding machinery technology, and in particular to a hollow blow molding machine and its multi-layer electronically controlled co-extrusion die head. Background Technology

[0002] The three-layer co-extrusion die head is the core component of a three-layer continuous extrusion blow molding machine. Its function is to extrude and form a three-layer molten annular plastic preform. During the extrusion process, the mandrel connected to the exit end of the drive unit moves continuously. By continuously changing the gap at the exit end, a preform with a set curved wall thickness is obtained. The preform is then transferred by the clamping device to the mold for blow molding, cooling and shaping, thereby producing a three-layer hollow plastic product.

[0003] Large-scale co-extrusion die heads with an extrusion output greater than 300 kg / h (HDPE raw material) are generally driven by hydraulic cylinders, which require a large driving force. Their movement is controlled by a hydraulic system and servo valves. The hydraulic cylinder is connected to the mandrel at the outlet end, which moves continuously, changing the gap at the outlet end to obtain a preform with a set curved wall thickness.

[0004] The disadvantages of using a hydraulic cylinder drive system are as follows: 1. Due to the inherent precision and response speed of the hydraulic servo valve, as well as the inertia of the hydraulic cylinder piston, its control accuracy and repeatability are limited. The wall thickness and weight of the extruded preform will deviate somewhat in each cycle, ultimately affecting the uniformity of the product's wall thickness and weight. 2. A complete hydraulic system is required, including an oil tank, motor, oil pump, valve assembly, sealing elements, and pipelines to supply oil to the hydraulic cylinder and control its movement. 3. Hydraulic cylinders, hydraulic valve assemblies, and sealing elements are prone to failure, resulting in poor maintainability. Furthermore, the hydraulic system can impact the environment and cannot meet the production requirements for high-cleanliness products. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies, the purpose of this invention is to provide a hollow blow molding machine and its multi-layer electronically controlled co-extrusion die head.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A multi-layer electrically controlled co-extrusion die head includes: a power mechanism, the output end of which is connected to a mandrel, and a mandrel with a mandrel mounted at its end; a multi-layer flow channel assembly is fixedly mounted on the outer wall of the power mechanism via a connecting plate, a tie rod, and a connecting plate, the multi-layer flow channel assembly having an inlet, through which molten plastic enters a spiral flow channel for melt distribution, and after merging, forms a multi-layer cylindrical preform; the output end of the multi-layer flow channel assembly is connected to a merging cavity, and a heating element is provided outside the merging cavity; the output end of the merging cavity is provided with a die matching the mandrel.

[0007] The power mechanism includes an electric cylinder, on which a speed-adjustable servo motor is mounted.

[0008] The spindle is fixedly mounted to the output end of the servo motor via a connecting flange.

[0009] The connector includes: a connecting plate installed on the outer wall of the electric cylinder, a connecting rod provided on the circumferential edge of the connecting plate, the other end of the connecting rod being connected to a connecting plate, and the connecting plate being connected to the multi-layer flow channel assembly.

[0010] The multi-layer flow channel assembly is a three-layer flow channel assembly, which includes three layers of flow channels assembled in a concentric circle structure. The three layers of flow channels are divided into an inner layer flow conductor, a middle layer flow conductor, and an outer layer flow conductor. The upper ends of the inner layer flow conductor, the middle layer flow conductor, and the outer layer flow conductor are fixedly installed on a connecting plate. The outlets of the inner layer flow conductor, the middle layer flow conductor, and the outer layer flow conductor converge and flow out through the gap between the core mold and the die, forming a three-layer structure preform.

[0011] The outer laminar conductor has a via for plastic to pass through.

[0012] The heating component is a heating coil disposed on the outer wall of the merging cavity.

[0013] A hollow blow molding machine includes a machine body on which a three-layer electrically controlled co-extrusion die head as described in the preceding claims is mounted. Compared with the prior art, the beneficial effects of the present invention are: This invention provides a hollow blow molding machine and its co-extrusion die head, which uses a servo motor to drive the mandrel movement via an electric cylinder, changing the traditional hydraulic drive method. Its advantages include: 1. Parison control accuracy and repeatability are improved by more than 3 times, thus ensuring uniform wall thickness and consistent weight. 2. The co-extrusion die head has a simple structure and high cleanliness, making it suitable for the production of high-cleanliness products. 3. The co-extrusion die head is easy to install and maintain, saving time and labor. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the co-extrusion die head structure of the present invention.

[0016] Figure 2 yes Figure 1 AA section view in the middle; Figure 3 yes Figure 1 BB section view in the middle; Figure 4 yes Figure 1 CC section view in the image.

[0017] In the figure, 1—servo motor; 2—power mechanism; 3—connecting plate; 31—connecting rod; 32—connecting plate; 4—connecting flange; 5—mandrel; 6—three-layer flow channel assembly; 61—inner laminar flow conductor; 62—middle laminar flow conductor; 63—outer laminar flow conductor; 7—heating coil; 8—die; 9—core mold; 10—preform. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the protection scope of the present invention.

[0020] like Figure 1-3 As shown, the present invention provides a multi-layer electronically controlled co-extrusion die head, comprising: a power mechanism 2, the output end of which is connected to a mandrel 5 via a connecting flange 4, and a mandrel 9 is installed at the end of the mandrel 5; a multi-layer flow channel assembly 6 is fixedly installed on the outer wall of the power mechanism 2 via a connecting plate 3, a tie rod 31, and a connecting plate 32, the multi-layer flow channel assembly 6 having three feed ports, through which molten plastic enters the spiral flow channel for melt distribution, and after merging, forms a multi-layer cylindrical preform; the output end of the multi-layer flow channel assembly 6 is connected to a merging cavity, and heating components are provided outside the merging cavity and the entire die head; the output end of the merging cavity is provided with a die 8 that matches the mandrel 9.

[0021] Specifically, the power mechanism 2 includes an electric cylinder, on which a speed-adjustable servo motor 1 is mounted. The spindle 5 is fixedly mounted to the output end of the servo motor 1 via a connecting flange 4. The connecting component includes a connecting plate 3 mounted on the outer wall of the electric cylinder, with a connecting rod 31 provided on the circumferential edge of the connecting plate 3. The other end of the connecting rod 31 is connected to the three-layer flow channel assembly 6. For example, the heating component is a heating coil 7 disposed on the outer wall of the merging cavity.

[0022] like Figure 4As shown, in this embodiment, a three-layer example is used for illustration: the multi-layer flow channel assembly 6 is a three-layer flow channel assembly, which includes three layers of flow channels assembled in a concentric circle structure. The three-layer flow channels are divided into an inner layer flow conductor 61, a middle layer flow conductor 62, and an outer layer flow conductor 63. The upper ends of the inner layer flow conductor 61, the middle layer flow conductor 62, and the outer layer flow conductor 63 are fixedly installed on the connecting plate 32. The outlets of the inner layer flow conductor 61, the middle layer flow conductor 62, and the outer layer flow conductor 63 converge and flow out through the gap between the core mold 9 and the die 8, forming a three-layer structure preform 10. The outer layer flow conductor 63 has through holes for plastic to pass through. The through holes on the outer layer flow conductor allow the inner and middle layers of plastic to pass through, enter the middle layer flow channel and the inner layer flow channel, and at the lower end of the flow channel body part, the three layers of plastic converge together and flow out through the gap between the core mold and the die, forming a three-layer structure cylindrical preform.

[0023] In addition, the present invention also provides a hollow blow molding machine, including a machine body on which the above-mentioned multi-layer electronically controlled co-extrusion die head is installed.

[0024] This invention relates to a large-scale servo-controlled multi-layer co-extrusion die head, which uses an electric cylinder to connect and drive the mandrel. Its working principle is as follows: three extruders are connected to the three feed ports of the co-extrusion die head. The extruders plasticize and melt the plastic raw material, which then flows into the inner, middle, and outer channels of the die head. After flow distribution through each channel, they converge into the direct current section and combine to form a three-layer plastic melt structure. The combined three-layer plastic melt continues to flow downwards and exits from the mandrel's annular gap at the outlet end, thus forming the desired preform. During this process, the mandrel, driven by the servo electric cylinder, moves according to a set time and position curve, continuously changing the width of the annular gap from which the plastic melt flows, resulting in a complete molten plastic preform of a set thickness in the axial direction. This preform is then transferred into the mold, inflated, shaped, cooled, and then removed from the mold to obtain the formed hollow blow-molded product.

[0025] The electric cylinder integrates a reducer, on which a servo motor is mounted. It is connected to a mandrel via a flange at the bottom, and the mandrel mold is mounted at the end of the mandrel. The servo motor drives the electric cylinder, which in turn moves the mandrel mold up and down via the mandrel. The gap between the mandrel mold and the die is the parison exit gap. The exit gap determines the parison thickness; the up-and-down movement of the mandrel mold causes the exit gap to change, thus affecting the parison thickness.

[0026] The co-extrusion die head is a key part of the continuous co-extrusion blow molding process. During the process of distributing the plastic melt to form a cylindrical preform, the servo motor drives the electric cylinder, which in turn drives the mandrel to move up and down to adjust the exit gap between the mandrel and the die, so that the plastic preform produces thickness changes on the circumference, which determines the uniformity of the wall thickness and the consistency of the weight of the final molded product.

[0027] The innovation of this invention lies in using a servo motor to drive the mandrel movement via an electric cylinder, thus changing the traditional hydraulic drive method. Its advantages include: 1. The control accuracy and repeatability of the parison are improved by more than three times, thereby ensuring uniform wall thickness and consistent weight. 2. The co-extrusion die head has a simple structure and high cleanliness, making it suitable for the production of high-cleanliness products. 3. The co-extrusion die head is easy to install and maintain, saving time and effort.

[0028] It will be apparent to those skilled in the art that the above specific examples are merely preferred embodiments of the present invention. Therefore, any improvements or modifications that may be made by those skilled in the art to certain parts of the present invention still embody the principles of the present invention and achieve the objectives of the present invention, and all fall within the scope of protection of the present invention.

Claims

1. A multi-layer electronically controlled co-extrusion die head, characterized in that, include: The power mechanism (2) is connected to a mandrel (5) at its output end, and a mandrel (9) is installed at the end of the mandrel (5). A multi-layer flow channel assembly (6) is fixedly installed on the outer wall of the power mechanism (2) through a connecting plate (3), a pull rod (31) and a connecting plate (32). The multi-layer flow channel assembly (6) is provided with an inlet. The plastic melt enters the spiral flow channel through the inlet, and the melt is distributed and merged to form a multi-layer cylindrical preform. The output end of the multi-layer flow channel assembly (6) is connected to the merging cavity. A heating component is provided outside the merging cavity. The output end of the merging cavity is provided with a die (8) that matches the mandrel (9).

2. The multi-layer electronically controlled co-extrusion die head according to claim 1, characterized in that, The power mechanism (2) includes an electric cylinder, on which a speed-adjustable servo motor (1) is mounted.

3. The multi-layer electronically controlled co-extrusion die head according to claim 2, characterized in that, The spindle (5) is fixedly installed on the output end of the servo motor (1) via the connecting flange (4).

4. The multi-layer electronically controlled co-extrusion die head according to claim 2, characterized in that, The connector includes a connecting plate (3) installed on the outer wall of the electric cylinder, a connecting rod (31) provided on the circumferential edge of the connecting plate (3), the other end of the connecting rod (31) being connected to a connecting plate (32), and the connecting plate (32) being connected to the multi-layer flow channel assembly (6).

5. The multi-layer electronically controlled co-extrusion die head according to claim 4, characterized in that, The multi-layer flow channel assembly (6) is a three-layer flow channel assembly, which includes three layers of flow channels assembled in a concentric circle structure. The three layers of flow channels are divided into an inner layer flow conductor (61), a middle layer flow conductor (62), and an outer layer flow conductor (63). The upper ends of the inner layer flow conductor (61), the middle layer flow conductor (62), and the outer layer flow conductor (63) are fixedly installed on the connecting plate (32). The outlets of the inner layer flow conductor (61), the middle layer flow conductor (62), and the outer layer flow conductor (63) converge and flow out through the gap between the core mold (9) and the die (8) to form a three-layer structure blank (10).

6. The multi-layer electronically controlled co-extrusion die head according to claim 5, characterized in that, The outer laminar conductor (63) has a through hole for plastic to pass through.

7. The multi-layer electronically controlled co-extrusion die head according to claim 1, characterized in that, The heating component is a heating coil (7) disposed on the outer wall of the confluence cavity.

8. A hollow blow molding machine, characterized in that, It includes a machine body on which a multi-layer electronically controlled co-extrusion die head as described in any one of claims 1-7 is mounted.

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