Mother-son machine applied to supercritical foaming blank injection

Abstract

The invention relates to a primary-secondary machine applied to supercritical foaming blank injection, which comprises an extruder, a material storage barrel and a mold, a cavity is arranged in the extruder, a double-step exhaust screw is arranged in the cavity, a feed port and a discharge port are respectively arranged at the left end and the right end of the extruder, the discharge port is communicated with the bottom of the material storage barrel, a piston is arranged in the material storage barrel, a nozzle is arranged at the bottom of the material storage barrel, and the mold is arranged in the cavity. The nozzle is communicated with the mold, a vacuum port is formed in the middle of the extruder and communicated with a vacuumizing device, and the discharge port is provided with a non-return ring used for preventing melt from flowing back into the extruder. According to the master-slave machine, air bubbles in small injection molding blanks are remarkably reduced by strengthening exhaust and inhibiting melt backflow, and the yield is increased.

Description

Technical Field

[0001] The present invention relates to the field of injection molding and foaming, and particularly to a master-slave machine applied to supercritical foaming injection embryo. Background Art

[0002] Existing supercritical foaming injection embryo processes usually adopt conventional injection molding machines, such as disk injection molding machines, vertical injection molding machines, horizontal injection molding machines, etc. These injection molding machines have the following problems during the production process:

[0003] 1. Melt backflow. During the material preparation and injection processes, the reciprocating motion of the traditional screw inevitably causes melt backflow. Especially for low-viscosity melts, backflow easily leads to the phenomenon of air pockets, affecting the injection molding quality.

[0004] 2. Insufficient exhaust. The exhaust of the traditional screw depends on the progressive compression of the screw, causing the gas to be discharged towards the root of the screw. However, inappropriate compression ratios often lead to excessive shear of the material, resulting in a decline in physical properties.

[0005] 3. Material sharing. Different materials (such as TPU, TPEE, PEBA, etc.) have different requirements for the compression ratio of the screw. When using the same machine for production, it is easy to have a high defective rate due to the mismatch of the compression ratio.

[0006] 4. During the supercritical foaming injection embryo process, the small embryo contains air bubbles. The small embryos obtained by injection molding often contain small air bubbles, affecting the subsequent foaming process and resulting in a high defective rate. Summary of the Invention

[0007] The present invention provides a master-slave machine applied to supercritical foaming injection embryo to solve the problems existing in the existing injection molding and foaming equipment, such as melt backflow, insufficient exhaust, small embryos containing air bubbles, and high defective rates.

[0008] The present invention adopts the following technical solutions:

[0009] A master-slave machine applied to supercritical foaming injection embryo includes an extruder, a storage barrel, and a mold. The extruder is provided with a cavity inside, and a two-stage exhaust screw is arranged in this cavity. The left and right ends of the extruder are respectively provided with a feed inlet and a discharge outlet. The discharge outlet is communicated with the bottom of the storage barrel. A piston is arranged in the storage barrel, and a nozzle is arranged at the bottom of the storage barrel. The nozzle is communicated with the mold. A vacuum port is arranged in the middle of the above-mentioned extruder, and the vacuum port is communicated with a vacuum pumping device. A check ring for preventing the melt from flowing back into the extruder is arranged at the above-mentioned discharge outlet.

[0010] Further, it also includes a motor, and the output end of the motor is connected to the above-mentioned two-stage exhaust screw.

[0011] Further, the above-mentioned piston is connected with a piston rod, and the piston rod is connected to a hydraulic device.

[0012] Furthermore, heat insulation layers or heating devices are provided on the outer walls of the above-mentioned material storage barrel and the above-mentioned nozzle.

[0013] Furthermore, a scale is provided on the outer wall of the above-mentioned material storage barrel.

[0014] Furthermore, a locking valve is provided on the above-mentioned nozzle.

[0015] From the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages:

[0016] 1. The master-slave machine of the present invention significantly reduces the bubbles in the injection-molded blanks and improves the yield rate by strengthening exhaust and suppressing melt backflow.

[0017] 2. The extruder of the master-slave machine of the present invention has a lower rotational speed and a longer double-stage exhaust screw, which is conducive to the curing reaction of the resin, reduces the shear of the resin, and avoids the decline of physical properties.

[0018] 3. The cylindrical material storage barrel of the master-slave machine of the present invention measures the material quantity more accurately, ensuring that the material quantity for each injection molding is consistent.

[0019] 4. Different materials of the master-slave machine of the present invention can share the same double-stage exhaust screw without causing the problem of excessive shear. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the master-slave machine of the present invention.

[0021] Wherein,

[0022] 1. Extruder; 2. Material storage barrel; 3. Mold; 4. Hydraulic device; 5. Motor; 10. Cavity; 11. Double-stage exhaust screw; 12. Check valve; 13. Vacuum device; 101. Feed inlet; 102. Discharge outlet; 103. Vacuum port; 21. Piston; 22. Scale; 23. Locking valve; 201. Nozzle; 211. Piston rod; DETAILED DESCRIPTION OF THE INVENTION

[0023] The following describes the specific embodiments of the present invention with reference to the drawings.

[0024] Refer to Figure 1, A master-slave machine applied to supercritical foaming injection molding, including an extruder 1, a storage barrel 2, and a mold 3. There is a cavity 10 inside the extruder 1, and a two-stage exhaust screw 11 is arranged in this cavity 10. The left end of the extruder 1 is provided with a feed inlet 101, and the right end is provided with a discharge outlet 102. The injection molding raw material is put into the cavity 10 through the feed inlet 101, and the two-stage exhaust screw 11 rotates to push the injection molding raw material melt towards the discharge outlet 102. The discharge outlet 102 communicates with the bottom of the storage barrel 2, and the discharge outlet 102 transports the melt to the storage barrel 2 through a heat preservation pipeline. There is a piston 21 inside the storage barrel 2, and a nozzle 201 is provided at the bottom of the storage barrel 2. This nozzle 201 communicates with the mold 3. A vacuum port 103 is provided in the middle of the above-mentioned extruder 1, and this vacuum port 103 communicates with a vacuum pumping device 13. A check ring 12 for preventing the melt from flowing back into the extruder 1 is provided at the above-mentioned discharge outlet 102. The check ring 12 can also be replaced with a thimble structure to block the discharge outlet 102 of the extruder 1 with the thimble.

[0025] It also includes a motor 5 and a control box (not shown in the figure). The output end of this motor 5 is connected to the above-mentioned two-stage exhaust screw 11. The motor 5 is used to drive the two-stage exhaust screw 11 to rotate, and the control box is used to send instructions to the above-mentioned extruder 1, vacuum pumping device 13, storage barrel 2, and mold 3 to work.

[0026] The above-mentioned piston 21 is connected with a piston rod 211. The piston rod 211 extends upward above the storage barrel 2. The piston rod 211 is connected to a hydraulic device 4, and this hydraulic device 4 controls the lifting of the piston rod 211.

[0027] Heat preservation layers or heating devices are provided on the outer walls of the above-mentioned storage barrel 2 and the above-mentioned nozzle 201 to ensure that the injection molding raw material remains in a molten state.

[0028] A scale 22 is provided on the outer wall of the above-mentioned storage barrel 2. The scale 22 is used to record and control the moving position of the piston 21.

[0029] A locking valve 23 is provided on the above-mentioned nozzle 201.

[0030] During material preparation, the front and back of the vacuum port 103 are sealed by the melt. When the melt advances forward, the middle section of the two-stage exhaust screw 11 has a deeper thread. The middle section is aligned with the vacuum port 103, and the air and other volatile substances in it are continuously sucked away by the strong negative pressure at the vacuum port 103. The melt at the end of the extruder 1 pushes the piston 21 backward until it reaches the set scale. At this time, the extruder 1 stops rotating, and the pre-compression of the piston 21 closes the check ring 12 of the extruder 1. After the mold 3 is in place, the hot runner locking valve 23 is opened, and the piston 21 advances forward to complete the injection and holding pressure actions according to a certain pressure, flow rate, and time. Then the locking valve 23 is closed, the extruder 1 is started, and the material preparation restarts for the next cycle.

[0031] The master-slave machine of the present invention is added with an active vacuum exhaust function. Since the rotation speed of the extruder 1 is relatively slower than that of the injection molding machine, different materials can share the same double-stage exhaust screw 11 without causing excessive shear problems; the double-stage exhaust screw 11 of the extruder 1 is relatively long, which increases the residence time of the material, is beneficial to the post-reaction curing process of TPU materials, and also increases the mixing time, which is beneficial to obtaining a melt with better and more uniform performance. The extruder 1 with exhaust is connected to the cylindrical storage barrel 2. When the extruder 1 works, the melt flows into the storage barrel 2, pushing the piston 21 to move backward. The position where the piston 21 moves is recorded and controlled by the scale. When the material quantity reaches the set position, the extruder 1 stops rotating, and the piston 21 is pre-compressed, resulting in the closure of the stop ring at the front section of the double-stage exhaust screw 11, and the material preparation is completed. The advantages of such a design are as follows: 1. The rotation speed of the extruder 1 is relatively low, and the double-stage exhaust screw 11 is relatively long, which is beneficial to the curing reaction of some resins and also reduces the shear of the resins; 2. An exhaust port is provided in the middle of the double-stage exhaust screw 11, which is beneficial to the discharge of volatile components and air; 3. The material quantity measurement of the cylindrical storage barrel 2 is more accurate.

[0032] The above is only the specific implementation manner of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantive modification made to the present invention using this concept shall fall within the scope of infringement of the protection scope of the present invention.

Claims

1. A master-slave machine applied to supercritical foaming injection molding, comprising an extruder, a storage barrel and a mold. The extruder is provided with a cavity inside, and a two-stage exhaust screw is arranged in the cavity. The left and right ends of the extruder are respectively provided with a feed inlet and a discharge outlet. The discharge outlet is communicated with the bottom of the storage barrel. A piston is arranged in the storage barrel, and a nozzle is arranged at the bottom of the storage barrel. The nozzle is communicated with the mold, and it is characterized in that: A vacuum port is provided in the middle of the extruder, and the vacuum port is connected to a vacuum pumping device. A check ring for preventing the melt from flowing back into the extruder is provided at the discharge port.

2. The mother-and-child machine applied to supercritical foaming injection molding as described in claim 1, wherein: It further includes a motor, and the output end of the motor is connected to the two-stage exhaust screw.

3. The mother-daughter machine applied to supercritical foaming injection molding embryo according to claim 1, characterized in that: The piston is connected to a piston rod, and the piston rod is connected to a hydraulic device.

4. A master-slave machine applied to supercritical foaming injection molding as described in claim 1, characterized in that: Heat insulation layers or heating devices are provided on the outer walls of the storage barrel and the nozzle.

5. A master-slave machine applied to supercritical foaming injection molding as claimed in claim 1, characterized in that: A scale is provided on the outer wall of the storage barrel.

6. The mother-daughter machine applied to supercritical foaming injection molding as described in claim 1, characterized in that: A locking valve is provided on the nozzle.

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