A screw for a twin-screw injection molding machine

Abstract

The utility model discloses a screw rod of double screw rod injection shooting platform belongs to injection molding machine field, through the sliding plug of spiral rod on the sliding, when material enters the discharge pipe, can smoothly push the sliding plug, make the sliding plug remove to separate the inside of discharge pipe and open, to let material can smoothly enter the mould, after the inside material of mould fills saturation, at this moment can through the contraction of pressure cylinder, to let spiral rod remove from the discharge port direction, to give material and let material can accumulate between the discharge port and spiral rod.

Description

Technical Field

[0001] This utility model discloses a screw for a twin-screw injection stage, belonging to the field of injection molding machines. Background Technology

[0002] A screw extruder is a device used to heat and stir plastic granules and extrude them.

[0003] In existing screw extruders, when performing material injection molding, the screw often needs to maintain pressure on the material injected into the mold by rotating in place. However, as the screw rotates, it continuously pushes the material outward. When rotating in place, the material cannot be pushed, resulting in direct friction between the material and the screw. Furthermore, due to the pressure holding function, most of the screw rotation in the screw extruder does ineffective work during the injection molding process, which is very wasteful.

[0004] A new solution is proposed to address the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a screw for a twin-screw injection station in order to solve the above-mentioned problems.

[0006] This utility model achieves the above-mentioned objective through the following technical solution: a screw for a twin-screw injection station, comprising... The machine body, placed on the ground, serves to support the various components and is equipped with a motor for driving them; The discharge pipe is installed on the machine body and is used to transport materials. The inlet of the discharge pipe is located in the middle. The screw rod is movably installed inside the discharge pipe, with threaded protrusions on its surface, and one end is detached and fixed to the motor output end. It is used to push the material inside the discharge pipe to move. The sliding plug is fitted onto the surface of the screw rod and moves with the screw rod. A pressure cylinder, mounted on the machine body, is used to drive the motor to move; The spiral rod is provided with a sealing protrusion and a pressure-boosting protrusion. The sliding plug can slide to combine with the sealing protrusion to form a partition between two cavities in the discharge pipe. The pressure-boosting protrusion slides in a sealed fit with the discharge pipe. The length of the discharge pipe is greater than the length between the pressure-boosting protrusion and the sealing protrusion.

[0007] Preferably, the discharge pipe is provided with a flow guiding protrusion, which can abut against the sliding plug.

[0008] Preferably, the sealing protrusion is conical in shape, and its bottom diameter is larger than the inner diameter of the sliding plug.

[0009] Preferably, a frustum is provided on the side of the lower base of the sealing protrusion away from the cone, and the upper diameter of the frustum is the same as the diameter of the screw.

[0010] Preferably, the circular platform is provided with a guide bar that mates with the threaded protrusion.

[0011] Preferably, the distance from the bottom of the sealing protrusion to the inner wall of the discharge pipe is equal to the maximum stroke of the sliding plug.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: The sliding plug on the screw rod allows the material to smoothly push the sliding plug when entering the discharge pipe, causing the sliding plug to move and open the partition inside the discharge pipe, thus allowing the material to smoothly enter the mold. Once the mold is saturated with material, the screw rod can be moved away from the discharge port by the contraction of the pressure cylinder, making room for the material to accumulate between the discharge port and the screw rod. When the next mold feeding is needed, the pressure cylinder pushes the screw rod towards the discharge port. As the screw moves in the direction of rotation, the sliding plug does not slide along with the screw because it can slide along the screw. It continues until the sliding plug slides to fit against the sealing protrusion. At this point, the sliding plug and the sealing protrusion cooperate to form a sealed surface. Due to the push of the pressure cylinder, the sealed surface moves towards the discharge port, thereby squeezing the previously accumulated material into the mold. This allows the material stored during the feeding waiting period to quickly enter the mold, thereby improving injection molding efficiency. It can also be used for pressure injection molding of molds with more delicate shapes, thereby achieving better molding results. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a cross-sectional structural diagram of the present invention; Figure 3 for Figure 2 A magnified schematic diagram of the structure at point A in the middle.

[0014] Reference numerals in the attached diagram: 1. Machine body; 2. Upper injection platform; 31. Discharge pipe; 32. Spiral rod; 33. Sliding plug; 34. Pressure boosting protrusion; 35. Sealing protrusion; 36. Frustum; 37. Guide protrusion; 5. Pressure cylinder. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. In the description of the present utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the present utility model and simplifying the description. They 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 present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0016] like Figure 1 , Figure 2 , Figure 3 As shown, a screw of a twin-screw injection stage includes... The main body 1 is placed on the ground to support the various components and is equipped with a motor for driving them; The discharge pipe 31 is installed on the machine body 1 and is used to transport materials. The inlet of the discharge pipe 31 is located in the middle. The screw rod 32 is movably disposed inside the discharge pipe 31, with threaded protrusions formed on its surface, and one end is detached and fixed to the motor output end, used to push the material inside the discharge pipe 31 to move. The sliding plug 33 is fitted onto the surface of the screw rod 32 and moves with the screw rod 32. Pressure cylinder 5, mounted on the machine body 1, is used to drive the motor to move; The spiral rod 32 is provided with a sealing protrusion 35 and a pressure-boosting protrusion 34. The sliding plug 33 can slide to combine with the sealing protrusion 35 to form a partition between two cavities of the discharge pipe 31. The pressure-boosting protrusion 34 slides in a sealed fit with the discharge pipe 31. The length of the discharge pipe 31 is greater than the length between the pressure-boosting protrusion 34 and the sealing protrusion 35.

[0017] When using this product, it needs to be installed on the lower screw injection position of a twin-screw injection molding machine. The upper injection stage 2 is used for initial melting and stirring of the material, which is then fed into the lower injection stage for secondary stirring. Next, under the action of the screw 32, the material is extruded through the discharge port of the discharge pipe 31 into the mold. Once the mold is full, the continuously rotating screw 32 exerts a pushing force on the material. Since the material cannot be pushed, it generates a reaction force on the screw 32. As the screw 32 continues to rotate, it experiences a force moving away from the discharge port. When this reaction force exceeds a threshold, the pressure cylinder 5 contracts, causing the screw 32 to move away from the discharge port. After the screw 32 moves, the space it originally occupied is freed up, allowing the material to flow into this freed-up space. This space serves as the material storage space for this product. Furthermore, when the extruded material solidifies and another mold is being injected, the pressure cylinder 5 pushes the screw... The screw rod 32 moves towards the discharge port. Due to the action of the sliding plug 33, when the screw rod 32 moves towards the discharge port, the sliding plug 33 divides the inside of the discharge pipe 31 into two cavities. The movement of the screw rod 32, which is made of rigid material, means that since the material has no space to move except at the discharge port, the pressure cylinder 5 transmits pressure to the material through the screw rod 32, allowing the material to be quickly squeezed into the mold along the discharge port, forming a die-casting effect. At the same time, it speeds up the material feeding speed, significantly improving work efficiency. When all the material has been squeezed in, the normal rotation of the screw rod 32 will push the material to continue moving. The material will then push the sliding plug 33, allowing the sliding plug 33 to move to keep the discharge pipe 31 unobstructed. This completes one feeding process. This product can adjust the pressure of the injection station on the material inside the mold by setting the pressure of the pressure cylinder 5, making the injection molding of different materials in different molds more stable.

[0018] The discharge pipe 31 is provided with a flow guiding protrusion 37, which can abut against the sliding plug 33. When the material pushes the sliding plug 33 to move, the flow guiding protrusion 37 can prevent the material from accumulating at a wide position after passing through the discharge pipe 31 due to the sudden narrowing of the discharge inner diameter of the discharge pipe 31 caused by the sliding plug 33.

[0019] The sealing protrusion 35 is conical in shape, and its bottom diameter is larger than the inner diameter of the sliding plug 33, which further improves the sealing effect and allows the pressure cylinder 5 to apply force better when pushed.

[0020] A frustum 36 is provided on the side of the lower base of the sealing protrusion 35 away from the cone. The upper diameter of the frustum 36 is the same as the diameter of the screw. The frustum 36 allows the material to better bypass the surface of the sealing protrusion 35, thereby avoiding material accumulation. At the same time, the guide bar allows the material to be pushed better, thereby achieving a better feeding effect.

[0021] The distance from the bottom of the sealing protrusion 35 to the inner wall of the discharge pipe 31 is equal to the maximum stroke of the sliding plug 33, which allows the material to be discharged more smoothly after passing over the sealing protrusion 35, effectively preventing air bubbles caused by uneven material discharge.

[0022] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0023] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A screw for a twin-screw injection stage, characterized in that, include The machine body, placed on the ground, serves to support the various components and is equipped with a motor for driving them; The discharge pipe is installed on the machine body and is used to transport materials. The inlet of the discharge pipe is located in the middle. The screw rod is movably installed inside the discharge pipe, with threaded protrusions on its surface, and one end is detached and fixed to the motor output end. It is used to push the material inside the discharge pipe to move. The sliding plug is fitted onto the surface of the screw rod and moves with the screw rod. A pressure cylinder, mounted on the machine body, is used to drive the motor to move; The spiral rod is provided with a sealing protrusion and a pressure-boosting protrusion. The sliding plug can slide to combine with the sealing protrusion to form a partition between two cavities in the discharge pipe. The pressure-boosting protrusion slides in a sealed fit with the discharge pipe. The length of the discharge pipe is greater than the length between the pressure-boosting protrusion and the sealing protrusion.

2. The screw of a twin-screw injection stage according to claim 1, characterized in that: The discharge pipe is provided with a flow guiding protrusion, which can abut against the sliding plug.

3. The screw of a twin-screw injection stage according to claim 1, characterized in that: The sealing protrusion is conical in shape, and its bottom diameter is larger than the inner diameter of the sliding plug.

4. The screw of a twin-screw injection stage according to claim 1, characterized in that: A frustum is provided on the side of the lower base of the sealing protrusion away from the cone head, and the upper base diameter of the frustum is the same as the screw diameter.

5. The screw of a twin-screw injection stage according to claim 4, characterized in that: The circular platform is provided with a guide bar that mates with the threaded protrusion.

6. The screw of a twin-screw injection station according to claim 1, characterized in that: The distance from the bottom of the sealing protrusion to the inner wall of the discharge pipe is equal to the maximum stroke of the sliding plug.

Images