A low-temperature extrusion anti-yellowing molding system for acrylic sheets

Abstract

This utility model discloses a low-temperature extrusion anti-yellowing molding system for acrylic sheets, relating to the technical field of acrylic sheet production. It includes a processing box, a roller conveyor, a melting tank, and an annular heating frame. The processing box has a hinged door on its outer side. A roller conveyor runs through the interior of the processing box, and a molding mechanism is positioned directly above the roller conveyor. The molding mechanism injects the material and anti-yellowing material through vibration from the injection tank, thereby mixing different types of materials in a specific ratio. A heating mechanism is positioned on the outer side of the melting tank, and the heating mechanism adjusts according to the amount of material inside the melting tank. When the eccentric wheel is driven to rotate by a motor, the rotation of the shaft generates a periodic centrifugal force that deviates from the rotation axis. This forces the contact surfaces within the eccentric groove to repeatedly squeeze / release, forming high-frequency micro-amplitude vibrations. This ensures that the melt forms a spiral diffusion flow within the mold cavity, avoiding degradation caused by localized stagnation.

Description

Technical Field

[0001] This utility model relates to the technical field of acrylic sheet production, specifically to a low-temperature extrusion anti-yellowing forming system for acrylic sheets. Background Technology

[0002] Acrylic is a chemical material, also known as specially treated plexiglass. In the processing of acrylic sheets, PMMA granules are first used. The granules need to be pre-dried. After the PMMA monomer is mixed with the initiator, it is injected into the mold and polymerized at low temperature. The acrylic granules are added to the extruder and softened by heating. Under the push of the extruder, the material is shaped by the shaping mold. It is suitable for ultra-thick sheets or irregular shapes.

[0003] Acrylic is prone to thermal oxidation degradation at high temperatures, which leads to molecular chain breakage, affecting mechanical properties and transparency. High temperatures can also cause residual molecular chain orientation stress. High-temperature extrusion increases the internal stress of acrylic sheets, which reduces the crack resistance of acrylic sheets. Furthermore, during the molding process, a single injection structure can affect the uniformity of material proportioning and mixing. Utility Model Content

[0004] The purpose of this invention is to provide a low-temperature extrusion anti-yellowing molding system for acrylic sheets, so as to solve the above-mentioned defects caused by the prior art.

[0005] A low-temperature extrusion anti-yellowing forming system for acrylic sheets includes a processing box, a roller conveyor, a melting tank, and an annular heating frame. The processing box has a hinged door on its outer side. The roller conveyor runs through the interior of the processing box, and a forming mechanism is positioned directly above the roller conveyor. The forming mechanism injects the material and anti-yellowing material through vibration from the injection tank, thereby mixing different types of materials in a specific ratio. A heating mechanism is located on the outer side of the melting tank. This heating mechanism adjusts the heating area according to the amount of material inside the melting tank to prevent excessive localized heat from affecting the material extrusion efficiency.

[0006] Preferably, the heating mechanism includes a melting tank, a servo motor, pulleys, a ball screw, guide blocks, and an annular heating frame. The servo motor is positioned directly above the melting tank and is connected to the pulleys via a coupling. A ball screw is keyed to the outer side of another set of pulleys, and a guide block is connected to the outer side of the ball screw. The bottom end of the ball screw is connected to the top end of the processing chamber. Multiple sets of guide blocks are positioned on the outer side of the annular heating frame, which is located outside the melting tank. The melting tank is installed directly above the processing chamber, and a pipe at the top of the melting tank is connected to the bottom end of a filling tank.

[0007] Preferably, the melting tank is connected to the spiral blades via a servo motor mounted at its top.

[0008] Preferably, the melting tank is fitted to one side of the eccentric wheel through an eccentric groove at its top, and the width of the eccentric groove is greater than the width of the eccentric wheel.

[0009] Preferably, the forming mechanism includes a cylinder, a plate mold, an injection end, a spiral blade, a material injection tank, an eccentric wheel, and an eccentric groove. The cylinder is installed inside the processing box, and the plate mold is provided inside the processing box. The top end of the plate mold is connected to the bottom end of the injection end. The top flange of the injection end is connected to the bottom end of the molten material tank. An eccentric groove is provided at the top of the molten material tank, and an eccentric wheel is fitted to the outer side of the eccentric groove.

[0010] Preferably, the processing box is connected to one of the sets of plate molds via internally installed cylinders, and the plate molds are parallel to the roller conveyor.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1. When the eccentric wheel is driven to rotate by the motor, the rotation of the shaft generates a periodic centrifugal force that deviates from the rotation axis. This forces the contact surface in the eccentric groove to repeatedly squeeze / release, forming a high-frequency micro-amplitude vibration. During use, acrylic impact-resistant agents and ultraviolet absorbers are continuously injected into the interior of the melting tank to ensure that the melt forms a spiral diffusion flow in the mold cavity, avoiding degradation caused by local stagnation. The molten material is directly injected using the plate mold set at the bottom, thereby avoiding the material's quality from being heated for too long.

[0013] 2. During the processing, the servo motor drives the pulley to rotate. The heating frame and the lead screw nut are rigidly connected by a flange. Linear guide rails and sliders are used for auxiliary guidance to prevent the lead screw from bending due to lateral forces. The ball screw drives the annular heating frame to move vertically up and down, dynamically adjusting or controlling the heating part of the melting tank. It works with the internal heating wire of the melting tank to reheat the material. The preheating zone of the annular heating frame eliminates the internal stress of the material. The heating zone inside the melting tank accurately triggers the phase change, avoiding blistering or yellowing caused by local overheating. Attached Figure Description

[0014] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0015] Figure 2 This is a schematic diagram of the internal structure of the processing box in this utility model.

[0016] Figure 3 This is a schematic diagram of the cross-sectional structure of the melting tank in this utility model.

[0017] Figure 4 This is a schematic diagram of the annular heating frame structure in this utility model.

[0018] Figure 5 This is a schematic diagram of the overhead cross-section of the melting tank in this utility model.

[0019] in:

[0020] 1. Machined box body; 2. Box door; 3. Roller conveyor; 4. Melting tank; 5. Servo motor; 6. Pulley; 7. Heating mechanism; 8. Ball screw; 9. Forming mechanism; 10. Cylinder; 11. Plate mold; 12. Injection end; 13. Spiral blade; 14. Injection tank; 15. Eccentric wheel; 16. Eccentric groove; 17. Guide block; 18. Annular heating frame. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0022] like Figures 1 to 5 As shown, a low-temperature extrusion anti-yellowing forming system for acrylic sheets includes a processing box 1, a roller conveyor 3, a melting tank 4, and an annular heating frame 18. The processing box 1 is hinged to a door 2 on its outer side. The roller conveyor 3 runs through the interior of the processing box 1. A forming mechanism 9 is located directly above the roller conveyor 3. The forming mechanism 9 injects the material and anti-yellowing material through a vibrating injection tank 14, thereby mixing different types of materials in a specific ratio. A heating mechanism 7 is located on the outer side of the melting tank 4. The heating mechanism 7 adjusts the heating area according to the amount of material inside the melting tank 4 to avoid excessive local heat affecting the material extrusion efficiency.

[0023] In this embodiment, the heating mechanism 7 includes a melting tank 4, a servo motor 5, a pulley 6, a ball screw 8, guide blocks 17, and an annular heating frame 18. The servo motor 5 is positioned directly above the melting tank 4. The servo motor 5 is connected to the pulley 6 via a coupling shaft. The outer side of another set of pulleys 6 is keyed to the ball screw 8. The outer side of the ball screw 8 is connected to the guide blocks 17. The bottom end of the ball screw 8 is connected to the top end of the processing housing 1. Multiple sets of guide blocks 17 are arranged on the outer side of the annular heating frame 18. The annular heating frame 18 is located on the outside of the melting tank 4, which is installed directly above the processing box 1. The top pipe of the melting tank 4 is connected to the bottom of the injection tank 14. The servo motor 5 drives the pulley 6 to rotate, and the pulley 6 drives the ball screw 8 on one side to rotate, so as to make the annular heating frame 18 vertical and perform secondary adjustment of the heating part. At the same time, the annular heating frame 18 at different heights is adjusted to ensure that the heating is uniform during the processing or that the local heating temperature is too high, causing material deformation.

[0024] In this embodiment, the melting tank 4 is axially connected to the spiral blade 13 via a servo motor 5 at its top. The servo motor 5 drives the spiral blade 13 to mix the materials, thereby adjusting the mixing ratio of the anti-yellowing material for the acrylic sheet, adding ultraviolet absorbers and light stabilizers to inhibit photo-oxidation reactions.

[0025] In this embodiment, the melting tank 4 is attached to one side of the eccentric wheel 15 through the eccentric groove 16 opened at the top. The width of the eccentric groove 16 is greater than the width of the eccentric wheel 15. The eccentric wheel 15 vibrates the material inside the filling tank 14, thereby accelerating the uniformity of material injection.

[0026] In this embodiment, the forming mechanism 9 includes a cylinder 10, a plate mold 11, an injection end 12, a spiral blade 13, a material injection tank 14, an eccentric wheel 15, and an eccentric groove 16. The cylinder 10 is installed inside the processing box 1. The plate mold 11 is arranged inside the processing box 1. The top end of the plate mold 11 is connected to the bottom end of the injection end 12. The top flange of the injection end 12 is connected to the bottom end of the melting tank 4. An eccentric groove 16 is opened at the top of the melting tank 4. An eccentric wheel 15 is attached to the outside of the eccentric groove 16. The eccentric wheel 15 vibrates the inside of the melting tank 4, and the molten material is injected into the inside of the plate mold 11 by the injection end 12.

[0027] In this embodiment, the processing box 1 is connected to one of the sets of plate molds 11 through an internally installed cylinder 10. The plate molds 11 are parallel to the roller conveyor 3. The cylinder 10 drives the plate molds 11 to descend, so that the two sets of plate molds 11 are separated and the cooled shaping material in the plate molds 11 is taken out.

[0028] In practical applications, this low-temperature extrusion anti-yellowing molding system for acrylic sheets includes the following tasks:

[0029] Step 1: Before melting the material, the acrylic impact-resistant agent and the ultraviolet absorber are injected into the injection tank 14 in sequence. The granular material is stored by opening the melting tank 4. Then, the bottom pipe of the injection tank 14 is opened to inject the material into the melting tank 4. The operator turns on the servo motor 5, which drives the pulley 6 and the eccentric wheel 15 to rotate. The eccentric wheel 15 rotates repeatedly inside the eccentric tank 16, constraining the movement trajectory of the eccentric wheel 15. This converts the centrifugal force into high-frequency micro-amplitude vibration, so that the material is directly and evenly injected into the inside of the device. Then, the spiral blades 13 are used to mix and proportion the material.

[0030] Step 2: The rotation speed of the eccentric wheel 15 is controlled by the servo motor 5. Vibration keeps the material in the hopper or filling tank 14 in a micro-fluidized state to avoid bridging or voids. At the same time, the eccentric wheel 15 vibrates the material inside the melting tank 4. Meanwhile, the servo motor 5 drives the spiral blade 13 to rotate. Through mechanical shearing and convection, uniform dispersion is achieved to ensure the performance consistency of the modified material.

[0031] Step 3: After the materials are mixed, the internal parts of the materials are heated by the electric heating wire inside the melting tank 4. At the same time, according to the material capacity and requirements, the ball screw 8 is rotated by the pulley 6. The ball screw 8 drives the guide block 17 and the annular heating frame 18 to move vertically downward. After adjusting the position of the annular heating frame 18, the belt at the connection of the pulley 6 is disassembled, so that the annular heating frame 18 stops outside the melting tank 4. The spiral blade 13 is rotated by the servo motor 5, so that the materials are continuously mixed and heated. Then, the injected materials are continuously squeezed out through the injection end 12.

[0032] Step 4: The servo motor 5 drives the spiral blades 13 to rotate, generating shearing force to break up PMMA particles and accelerate melting. At the same time, the servo motor 5 drives the eccentric wheel 15 to rotate, causing bubbles in the melt inside the melting tank 4 to rise and burst, reducing product defects. Then, the molten material is directly injected into the plate mold 11 through the injection end 12. The plate mold 11 is used to shape the molten material. Then, the cylinder 10 separates one set of molds in the plate mold 11, separating the shaped acrylic sheet. Then, the box door 2 is opened, and the cooled acrylic sheet is placed on the roller conveyor 3 to lift the acrylic sheet and transport it out of the processing box 1.

[0033] Therefore, the above-disclosed embodiments are merely illustrative examples and not the only ones. All modifications within the scope of this utility model or its equivalents are included in this utility model.

Claims

1. A low-temperature extrusion anti-yellowing molding system for acrylic sheets, characterized in that: The equipment includes a processing box (1), a roller conveyor (3), a melting tank (4), and an annular heating frame (18). The processing box (1) is hinged to a door (2) on the outside. The roller conveyor (3) runs through the inside of the processing box (1). A forming mechanism (9) is set directly above the roller conveyor (3). The forming mechanism (9) injects the material and anti-yellowing material through the injection tank (14) with vibration, and then mixes different types of materials in proportion. A heating mechanism (7) is set on the outside of the melting tank (4). The heating mechanism (7) adjusts the heating part according to the amount of material inside the melting tank (4).

2. The acrylic sheet low-temperature extrusion anti-yellowing forming system according to claim 1, characterized in that: The heating mechanism (7) includes a melting tank (4), a servo motor (5), a pulley (6), a ball screw (8), a guide block (17), and an annular heating frame (18). The servo motor (5) is located directly above the melting tank (4). The servo motor (5) is connected to the pulley (6) via a coupling shaft. The outer side of another set of pulleys (6) is keyed to the top of the ball screw (8). The outer side of the ball screw (8) is connected to the guide block (17). The bottom end of the ball screw (8) is connected to the top of the processing box (1). Multiple sets of guide blocks (17) are arranged on the outer side of the annular heating frame (18). The annular heating frame (18) is located on the outer side of the melting tank (4). The melting tank (4) is installed through and directly above the processing box (1). The top pipe of the melting tank (4) is connected to the bottom end of the injection tank (14).

3. The low-temperature extrusion anti-yellowing forming system for acrylic sheets according to claim 2, characterized in that: The melting tank (4) is axially connected to the spiral blades (13) via a servo motor (5) mounted on its top.

4. The low-temperature extrusion anti-yellowing forming system for acrylic sheets according to claim 2, characterized in that: The melting tank (4) is attached to one side of the eccentric wheel (15) through an eccentric groove (16) opened at the top, and the width of the eccentric groove (16) is greater than the width of the eccentric wheel (15).

5. The low-temperature extrusion anti-yellowing forming system for acrylic sheets according to claim 1, characterized in that: The forming mechanism (9) includes a cylinder (10), a plate mold (11), an injection end (12), a spiral blade (13), a material injection tank (14), an eccentric wheel (15), and an eccentric groove (16). The cylinder (10) is installed inside the processing box (1). The plate mold (11) is provided inside the processing box (1). The bottom end of the injection end (12) is connected through the top end of the plate mold (11). The bottom end of the melting tank (4) is connected to the top flange of the injection end (12). An eccentric groove (16) is provided at the top end of the melting tank (4). An eccentric wheel (15) is fitted to the outside of the eccentric groove (16).

6. The low-temperature extrusion anti-yellowing forming system for acrylic sheets according to claim 5, characterized in that: The processing box (1) is connected to one of the plates molds (11) via internally installed cylinders (10), and the plates molds (11) are parallel to the roller conveyor (3).

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