Mould frame mechanism of high-molecular polylactic acid solid extrusion molding machine

Abstract

The utility model discloses a mould frame mechanism of a polymer polylactic acid solid extrusion forming machine, which comprises an ejector rod and a mould head, a discharging part is arranged at the rear end of the mould head, a discharging channel is arranged at the front end of the mould head, an extrusion forming channel with the inner diameter gradually reduced along the axial direction is arranged in the center of the mould head, and the extrusion forming channel is positioned between the discharging part and the discharging channel. And the ejector rod pushes the macromolecular polylactic acid bars in the discharging part into the extrusion forming channel through the pushing mechanism, and the macromolecular polylactic acid bars are pushed out of the discharging channel. Effective axial pressure is applied to the high-molecular polylactic acid charge bar through extrusion forming with the gradually-reduced inner diameter, the diameter of the charge bar is reduced and the density is improved in cooperation with the ejector rod and the pushing mechanism, and therefore the quality and performance of a formed product are improved.

Description

Technical Field

[0001] This utility model relates to the field of solid extrusion molding technology of polylactic acid (PLA), and particularly to the mold frame mechanism of a solid extrusion molding machine for PLA. Background Technology

[0002] Polylactic acid (PLA), as a biodegradable and environmentally friendly polymer material, has biodegradability and good biocompatibility, and is widely used in packaging, textiles, medical, 3D printing and industrial products.

[0003] Polylactic acid products are generally injection molded directly using injection molding machines. The products have low density and insufficient resistance to cracking, making it difficult to meet the requirements of high mechanical performance scenarios. Utility Model Content

[0004] The purpose of this invention is to provide a mold frame mechanism for a solid extrusion molding machine for polylactic acid (PLA) to solve the technical problem that PLA products obtained by injection molding have low density and insufficient crack resistance, making it difficult to meet the requirements for high mechanical properties.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The die frame mechanism of the polylactic acid solid extrusion molding machine includes a push rod and a die head. The rear end of the die head has a feeding section, the front end of the die head has a discharge channel, and the center of the die head has an extrusion molding channel with an inner diameter that gradually decreases along the axial direction. The extrusion molding channel is located between the feeding section and the discharge channel. The push rod pushes the polylactic acid material rod in the feeding section into the extrusion molding channel and pushes it out from the discharge channel.

[0007] As a preferred embodiment of this utility model, a heating oil channel is provided inside the die head, and the oil inlet of the heating oil channel is located near the top of the front end of the ejector pin.

[0008] As a preferred embodiment of this utility model, the mechanism further includes a pushing mechanism for pushing the push rod. The pushing mechanism includes a front fixed plate, a rear fixed plate, a lead screw sleeve, and a motor. The front fixed plate and the rear fixed plate are connected by a guide rod. A reducer is provided on the outer side of the rear fixed plate. The input end of the reducer is connected to the rotating shaft of the motor. A lead screw is fixedly connected to the output end of the reducer. The two ends of the lead screw sleeve are respectively provided with a front guide plate and a rear guide plate. A nut is provided on the lead screw sleeve near the reducer. The lead screw passes through the lead screw sleeve and is threadedly connected to the nut.

[0009] As a further preferred embodiment of this utility model, both the front guide plate and the rear guide plate are slidably sleeved on the guide rod via guide sleeves.

[0010] As a further preferred embodiment of this utility model, the push rod is installed at the front end of the front guide plate via a pressure assembly. The pressure assembly includes an assembly plate, which is fixedly disposed on the front side of the front guide plate. A pressure transmitter is provided at the front end of the assembly plate, and a fixing seat for fixing the push rod is provided at the front end of the pressure transmitter.

[0011] As a further preferred embodiment of this utility model, a mold head mounting hole for fixing the mold head is provided on the front fixing plate.

[0012] Compared with the prior art, the mold frame mechanism of the polylactic acid solid extrusion molding machine provided by this utility model has the following beneficial effects:

[0013] This invention improves the quality and performance of molded products by setting an extrusion molding channel with a gradually decreasing inner diameter, thereby reducing the diameter of the material bar and increasing its density.

[0014] The push rod and pushing mechanism work together to apply effective axial pressure to the polylactic acid (PLA) rod. The heating oil channel inside the die head precisely controls the temperature of the extrusion molding channel, which facilitates rod deformation and improves molding efficiency and quality.

[0015] The transmission method of the lead screw and nut, as well as the cooperation between the guide rod and the guide sleeve, ensure the smoothness and accuracy of the push rod movement, making the extrusion process more stable and reliable.

[0016] The pressure assembly can handle pressure changes during the extrusion process, adjust extrusion parameters in a timely manner, and ensure consistent product quality.

[0017] The mold frame mechanism has a compact structure, reasonable connections and coordination between its components, occupies little space, and is easy to install and operate. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only examples of embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0020] Figure 2 for Figure 1 A magnified structural diagram of part A in the diagram;

[0021] Figure 3 This is a partial cross-sectional view of an embodiment of the present utility model;

[0022] Figure 4 This is a schematic diagram of the mold head structure in an embodiment of this utility model;

[0023] Figure 5 This is a top view of the mold head in an embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the BB-direction cross-sectional structure of the mold head in an embodiment of this utility model;

[0025] Figure 7 This is a schematic diagram of the structure of the present invention when installed on a polylactic acid solid extrusion molding machine.

[0026] Figure label:

[0027] 1. Front fixed plate; 01. Rear fixed plate; 101. Die head mounting hole; 2. Front guide plate; 02. Rear guide plate; 3. Screw sleeve; 303. Nut; 4. Motor; 5. Reducer; 6. Screw; 7. Guide rod; 8. Guide sleeve; 9. Ejector rod; 10. Die head; 1001. Feeding section; 1002. Extrusion molding channel; 1003. Discharge channel; 1004. Oil inlet; 11. Assembly plate; 12. Pressure transmitter; 13. Fixing base. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0029] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present invention should be understood according to the specific circumstances.

[0031] See Figure 1 , 2As shown, the mold frame mechanism of the polylactic acid solid extrusion molding machine of this utility model includes a push rod 9 and a die head 10. The rear end of the die head 10 is provided with a feeding part 1001, the front end of the die head 10 is provided with a discharge channel 1003, and the center of the die head 10 is provided with an extrusion molding channel 1002 with an inner diameter that gradually decreases along the axial direction. The extrusion molding channel 1002 is located between the feeding part 1001 and the discharge channel 1003. The push rod 9 pushes the polylactic acid material rod in the feeding part 1001 into the extrusion molding channel 1002 and pushes it out from the discharge channel 1003.

[0032] In this embodiment of the invention, a polylactic acid (PLA) rod is placed in the feeding section 1001 of the die head 10, and the push rod 9 pushes the rod into the extrusion molding channel 1002. Because the inner diameter of the extrusion molding channel 1002 gradually narrows along the axial direction, the rod is constrained by the channel wall as it moves forward. The axial pressure reduces the diameter of the rod, making the internal molecular arrangement more compact, thereby increasing the density. Finally, the PLA product is extruded from the discharge channel 1003.

[0033] See Figure 4-6 As shown, a heating oil channel is provided inside the die head 10. The oil inlet 1004 of the heating oil channel is located at the top of the die head 10 near the ejector pin 9. During the extrusion process, heating oil is introduced into the heating oil channel inside the die head 10 through the oil inlet 1004. The heating oil transfers heat to the die head 10, thereby heating the polylactic acid (PLA) rod in the extrusion molding channel 1002. A suitable temperature can reduce the viscosity of the PLA, making it easier to deform during the extrusion process and improving the molding effect.

[0034] See Figure 1 , 3 As shown, this utility model embodiment also includes a pushing mechanism for pushing the push rod. The pushing mechanism includes a front fixed plate 1, a rear fixed plate 01, a lead screw sleeve 3, and a motor 4. The front fixed plate 1 and the rear fixed plate 01 are connected by a guide rod 7. A reducer 5 is provided on the outer side of the rear fixed plate 011. The input end of the reducer 5 is connected to the rotating shaft of the motor 4. A lead screw 6 is fixedly connected to the output end of the reducer 5. The two ends of the lead screw sleeve 3 are respectively provided with a front guide plate 2 and a rear guide plate 02. A nut 303 is provided on the lead screw sleeve 3 near the reducer 5. The lead screw 6 passes through the lead screw sleeve 3 and is threadedly connected to the nut 303.

[0035] In operation, the motor 4 starts, causing the reducer 5 to decelerate and increase torque, which is then transmitted to the lead screw 6, causing the lead screw 6 to rotate. Since the lead screw 6 is threadedly connected to the nut 303 on the lead screw sleeve 3, the rotation of the lead screw 6 drives the lead screw sleeve 3 to move axially along the lead screw 6. The front guide plate 2 and rear guide plate 02 at both ends of the lead screw sleeve 3 move accordingly, which in turn drives the push rod 9 to move via the pressure assembly, thus pushing the polylactic acid material rods within the discharge section 1001.

[0036] Both the front guide plate 2 and the rear guide plate 02 are slidably mounted on the guide rod 7 via the guide sleeve 8. The guide sleeve 8 reduces the friction between the front guide plate 2, the rear guide plate 02 and the guide rod 7, allowing the front guide plate 2 and the rear guide plate 02 to move more smoothly along the guide rod 7, ensuring the stability and accuracy of the movement of the push rod 9.

[0037] See Figure 2 As shown, in this embodiment of the present invention, the push rod 9 is installed at the front end of the front guide plate 2 through a pressure assembly. The pressure assembly includes an assembly plate 11, which is fixedly disposed at the front end of the front guide plate 2. A pressure transmitter 12 is provided at the front end of the assembly plate 11, and a fixing seat 13 for the push rod 19 is provided at the front end of the pressure transmitter 12.

[0038] During the process of pushing the polylactic acid (PLA) material bar by the push rod 9, the material bar will generate a reaction force on the push rod 9. This force is transmitted to the pressure transmitter 12 through the fixed seat 13 to record the pressure changes during the extrusion process in real time. The mounting plate 11 fixes and supports the pressure transmitter 12 to ensure accuracy. It should be noted that the pressure transmitter 12 in this embodiment of the present invention is not limited, as long as it meets the design requirements.

[0039] See Figure 3 As shown, the front fixed plate 1 has a die head mounting hole 101 for fixing the die head 10 to ensure the stability of the die head 10. During the process of the push rod 9 pushing the material bar into the die head 10, the die head 10 does not shift, ensuring the stability and consistency of the extrusion molding process, and allowing the material bar to accurately pass through the extrusion molding channel 1002 for molding.

[0040] See Figure 7 As shown in the embodiment of this utility model, when in use, a polylactic acid (PLA) material rod is placed in the feeding section 1001 of the die head 10. Heating oil is introduced into the heating oil channel of the die head 10 from the oil inlet 1004 to heat the die head 10, so that the extrusion molding channel 1002 reaches a suitable temperature.

[0041] The motor 4 starts rotating and transmits the rotation to the lead screw 6 via the reducer 5. The rotation of the lead screw 6 drives the lead screw sleeve 3 to move along the guide rod 7. The front guide plate 2 and the rear guide plate 02 at both ends of the lead screw sleeve 3 slide on the guide rod 7 through the guide sleeve 8 to ensure smooth movement.

[0042] The front guide plate 2 drives the push rod 9 forward through the pressure assembly. The push rod 9 pushes the material bar in the feeding section 1001 into the extrusion molding channel 1002. As the inner diameter of the extrusion molding channel 1002 gradually decreases, the diameter of the material bar decreases and the density increases under the action of axial pressure.

[0043] During the extrusion process, the pressure transmitter 12 adjusts parameters such as the speed of the motor 4 in real time as needed to ensure the stability of the extrusion process. The extruded polylactic acid is extruded from the discharge channel 1003, completing the molding process.

[0044] The foregoing has shown and described the basic principles of the present invention. The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. The above embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Any modifications, equivalent substitutions, and improvements made within the scope of the present invention without departing from the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. The die frame mechanism of a polylactic acid solid extrusion molding machine, characterized in that: The device includes a push rod (9) and a die head (10). The die head (10) has a feeding section (1001) at its rear end and a discharge channel (1003) at its front end. The die head (10) has an extrusion molding channel (1002) with an inner diameter that gradually decreases along the axial direction at its center. The extrusion molding channel (1002) is located between the feeding section (1001) and the discharge channel (1003). The push rod (9) pushes the polylactic acid material rod in the feeding section (1001) into the extrusion molding channel (1002) and pushes it out from the discharge channel (1003).

2. The die frame mechanism of the polylactic acid solid extrusion molding machine according to claim 1, characterized in that: The mold head (10) has a heating oil channel inside, and the oil inlet (1004) of the heating oil channel is located on the top of the mold head (10) near the front end of the push rod (9).

3. The die frame mechanism of the polylactic acid solid extrusion molding machine according to claim 1, characterized in that: It also includes a pushing mechanism for pushing the push rod (19), the pushing mechanism including a front fixed plate (1), a rear fixed plate (01), a lead screw sleeve (3) and a motor (4), the front fixed plate (1) and the rear fixed plate (01) are connected by a guide rod (7), a reducer (5) is provided on the outside of the rear fixed plate (01), the input end of the reducer (5) is connected to the shaft of the motor (4), the output end of the reducer (5) is fixedly connected to a lead screw (6), the two ends of the lead screw sleeve (3) are respectively provided with a front guide plate (2) and a rear guide plate (02), a nut (303) is provided on the lead screw sleeve (3) near the end of the reducer (5), the lead screw (6) passes through the lead screw sleeve (3) and is threadedly connected to the nut (303).

4. The die frame mechanism of the polylactic acid solid extrusion molding machine according to claim 3, characterized in that: The front guide plate (2) and the rear guide plate (02) are both slidably sleeved on the guide rod (7) through the guide sleeve (8).

5. The die frame mechanism of the polylactic acid solid extrusion molding machine according to claim 3, characterized in that: The push rod (9) is installed at the front end of the front guide plate (2) via a pressure assembly. The pressure assembly includes an assembly plate (11), which is fixedly disposed at the front end of the front guide plate (2). A pressure transmitter (12) is provided at the front end of the assembly plate (11), and a fixing seat (13) for fixing the push rod (9) is provided at the front end of the pressure transmitter (12).

6. The die frame mechanism of the polylactic acid solid extrusion molding machine according to claim 3, characterized in that: The front fixing plate (1) has a mold head mounting hole (101) for fixing the mold head (10).

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