WO2023103345A1

WO2023103345A1 - Single-screw extrusion injection apparatus

Info

Publication number: WO2023103345A1
Application number: PCT/CN2022/100854
Authority: WO
Inventors: 徐百平; 杨卫波; 喻慧文; 肖书平; 谈灵操; 杜遥雪
Original assignee: 五邑大学
Priority date: 2021-12-07
Filing date: 2022-06-23
Publication date: 2023-06-15
Also published as: CN114368119A

Abstract

A single-screw extrusion injection apparatus, comprising a machine barrel and a screw, the screw being arranged in the machine barrel, the screw being provided with a flight, and the screw being provided with a thrust flow guiding structure and a drag flow guiding structure. The starting end of the thrust flow guiding structure is connected to a thrust face, and the tail end of same extends in the direction of a drag face. The starting end of the drag flow guiding structure is connected to the drag face, and the tail end of same extends in the direction of the thrust face. The thrust flow guiding structure and the drag flow guiding structure form a gap between the flight and the inner wall of the machine barrel. A solid bed is pushed to turn over and migrate along the flow guiding direction, thus accelerating melt film migration, eliminating solid bed blockage and improving melting efficiency. Dependence on transverse circulation in the cross-section of the screw groove is reduced, and the heat transfer effect and distributive and dispersive mixing effects are enhanced.

Description

A single-screw extrusion injection device

technical field

The invention relates to the field of screw technology, in particular to a single-screw extrusion injection device.

Background technique

The single-screw mechanism has the advantages of simple structure, convenient operation and maintenance, and the ability to establish stable extrusion pressure, and is widely used in extrusion molding and injection molding processes. The single-screw mechanism is mainly based on the friction drag mechanism, and the flow can be decomposed into longitudinal positive flow along the development direction of the screw groove and transverse circulation perpendicular to the screw groove. Since melt plasticization and mixing mainly depend on transverse circulation, the ratio of transverse circulation to longitudinal positive flow intensity is tanθ, θ is the helix angle, and θ is usually 17.65 degrees. Therefore, the ratio of transverse to longitudinal flow intensities is approximately 0.3182. It can be seen that the transverse strength is about one-third of the longitudinal flow strength, and the macroscopic flow organization control of the longitudinal flow is the dominant factor of the single-screw mechanism. When the single-screw is applied to injection molding, the melting, plasticizing and kneading occurs during the retreat of the screw, which leads to a sharp increase in the longitudinal flow and a sharp decrease in the transverse flow. The ratio of the transverse and longitudinal flow intensities is even close to zero. The effect is very small, resulting in a significant drop in the efficiency of the injection screw.

On the other hand, the greater the output of the single-screw mechanism, the faster the movement speed of the material in the core area of the screw channel, the weaker the effect of the transverse circulation, and the more significant the non-uniformity of material melting and plasticization. In order to ensure the quality of single-screw plasticizing and melting, it is compensated by increasing the outlet back pressure, resulting in a decrease in output and an increase in energy consumption. In order to strengthen the melting, plasticizing and mixing capabilities of the single screw, a resistance element based on transverse circulation is used. The resistance element has multi-divided flow channels, and more stagnation points and dead zones are introduced in the flow channels, resulting in the self-cleaning ability of the screw. Decline, residence time distribution control is difficult. When the output increases, or in the injection molding process, the mixing efficiency of the single-screw mechanism based on cross circulation will drop significantly.

Contents of the invention

The purpose of the present invention is to at least solve one of the technical problems in the prior art, and provide a single-screw extrusion injection device.

The technical scheme that the present invention solves its problem adopts is:

A single-screw extrusion injection device, comprising:

Barrel;

A screw, the screw is located in the barrel, the outer surface of the screw is provided with a spiral flight extending along the axial direction of the screw, and the outer surface of the screw is provided with thrust guide structures arranged alternately and a drag guide structure, the beginning of the thrust guide structure is connected to the thrust surface of the screw flight, the end of the thrust guide structure extends toward the drag surface of the screw flight, and the drag guide structure The starting end is connected to the dragging surface of the screw flight, and the end of the drag guiding structure extends toward the thrust surface of the screw flight, and the thrust guiding structure and the drag guiding structure are connected between the screw flight and the A gap is formed between the inner walls of the barrel, and the thrust flow guide structure and the drag flow guide structure are used to form alternating vortices in the longitudinal flow direction.

Further, the thrust guide structure is streamlined, the cross section of the thrust guide structure gradually decreases from the beginning to the end, and the thrust guide structure moves from the side close to the screw to the side away from the screw Gradually narrows and forms the first guideline.

Further, the drag guide structure is streamlined, the cross section of the drag guide structure gradually decreases from the beginning to the end, and the drag guide structure moves from the side close to the screw to the side away from the screw Gradually narrows and forms a second guideline.

Further, the angle formed by the first guide line and the longitudinal flow direction is the first diversion angle α, and the angle formed by the second guide line and the longitudinal flow direction is the second diversion angle β, when 0<α<π/2, 0<β<π/2, the single-screw extrusion injection device adopts the parallel arrangement; when π/2<α<π, π/2<β<π, the The single-screw extrusion injection device adopts the reverse row method; when 0<α<π/2, π/2<β<π, the single-screw extrusion injection device adopts the mixed row method; when π/2<α<π , 0<β<π/2, the single-screw extrusion and injection device adopts a mixed arrangement.

Further, the expansion straight line length of the thrust diversion structure is less than πD sinγ/sinα, the expansion straight line length of the drag diversion structure is less than πD sinγ/sinβ, γ is the helix angle of the single screw flight, and D is the length of the outer diameter of the screw .

Further, the distance connecting the two thrust diversion structures is S1, and S1 satisfies πD/sin(γ/20)<S1<2πD/sinγ; the distance connecting the two drag diversion structures is S2, and S2 satisfies πD /sin(γ/20)<S2<2πD/sinγ.

Further, the distance between the adjacent thrust guide structure and the drag guide structure is S3, and S3 satisfies 0≤S3≤4πD/sinγ.

Further, the height between the beginning of the thrust diversion structure and the outer edge of the screw is h1, h1=aD; the height between the beginning of the drag diversion structure and the outer edge of the screw is h2, h2=aD; the range of a is 0.0001 to 0.005, and D is the length of the outer diameter of the screw.

Further, the outermost side of the flight is in contact with the inner wall of the barrel.

Further, the barrel includes a conveying section, a melting section, a mixing section and a homogenizing section connected in sequence.

The above-mentioned single-screw extrusion injection device has at least the following beneficial effects: the thrust diversion structure extends from the thrust surface and the drag diversion structure extends from the drag surface, which can push the solid bed to turn over and migrate along the diversion direction , to accelerate the migration of the melt film, eliminate the solid bed blockage, and effectively improve the melting efficiency; use the wall strengthening effect of the thrust surface and the drag surface, and use the vortex strengthening in the two-dimensional plane composed of the longitudinal flow direction and the width direction of the screw channel The function can reduce the dependence on the transverse circulation in the cross section of the screw groove; in addition, the narrow compression gap formed by the diversion structure and the side wall of the screw edge, the vortex in the expansion plane of the screw groove caused by the drainage of the diversion structure, and the diversion The cascade vortex effect caused by the local structure on the windward side and the leeward side of the structure can effectively enhance the heat transfer effect and the distribution, dispersion and mixing effect.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and example.

Fig. 1 is a structural diagram of a single-screw extrusion injection device according to an embodiment of the present invention;

Fig. 2 is the structural diagram of screw rod;

Fig. 3 is a structural diagram of a thrust diversion structure and a drag diversion structure adopting a parallel arrangement;

Fig. 4 is a structural diagram of a thrust diversion structure and a drag diversion structure adopting the reverse arrangement;

Fig. 5 is a structural diagram of a thrust diversion structure and a drag diversion structure adopting a mixed arrangement;

Fig. 6 is a structural schematic diagram of a thrust diversion structure;

Fig. 7 is a structural schematic diagram of a drag diversion structure;

Fig. 8 is a structural schematic diagram of the drag guide structure.

Detailed ways

This part will describe the specific embodiment of the present invention in detail, and the preferred embodiment of the present invention is shown in the accompanying drawings. Each technical feature and overall technical solution of the invention, but it should not be understood as a limitation on the protection scope of the present invention.

In the description of the present invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc. indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only In order to facilitate the description of the present invention and simplify the description, it does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, several means one or more, and multiple means more than two. Greater than, less than, exceeding, etc. are understood as not including the original number, and above, below, within, etc. are understood as including the original number. If the description of the first and second is only for the purpose of distinguishing the technical features, it cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features relation.

In the description of the present invention, unless otherwise clearly defined, words such as setting, installation, and connection should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

Referring to FIG. 1 and FIG. 2 , an embodiment of the present invention provides a single-screw 200 extrusion injection device.

The single-screw 200 extrusion injection device includes a barrel 100 and a screw 200 .

Wherein, the screw rod 200 is located in the barrel 100, the outer surface of the screw rod 200 is provided with a screw edge 210 extending helically along the axial direction of the screw rod 200, and the outer surface of the screw rod 200 is provided with a thrust flow guide structure 220 and a drag guide structure 220 arranged alternately. The flow structure 230, the beginning of the thrust guide structure 220 is connected to the thrust surface 201 of the screw flight 210, the end of the thrust guide structure 220 extends toward the dragging surface 202 of the screw flight 210, and the beginning of the drag guide structure 230 is connected to the screw flight 210. The drag surface 202 is connected, the end of the drag guide structure 230 extends toward the thrust surface 201 of the screw flight 210, the thrust guide structure 220 and the drag guide structure 230 form a gap between the screw flight 210 and the inner wall of the barrel 100, The thrust guide structure 220 and the drag guide structure 230 are used to form alternating vortices in the longitudinal flow direction.

In this embodiment, the thrust diversion structure 220 extends from the thrust surface 201 and the drag diversion structure 230 extends from the drag surface 202, which can push the solid bed to overturn and migrate along the diversion direction, thereby accelerating the melting process. The migration of the membrane eliminates the blockage of the solid bed, effectively improving the melting efficiency; using the wall strengthening effect of the thrust surface 201 and the dragging surface 202, and the vortex strengthening effect in the two-dimensional plane composed of the longitudinal flow direction and the width direction of the screw channel, It can reduce the dependence on the transverse circulation in the cross section of the screw groove; in addition, the effect of the narrow compression gap formed by the diversion structure and the side wall of the screw edge 210, the vortex in the expansion plane of the screw groove caused by the drainage of the diversion structure, and the diversion structure The cascade vortex effect caused by the local structure of the windward side and the leeward side can effectively enhance the heat transfer effect and the distribution, dispersion and mixing effect.

It should be noted that the left and right side walls of the flight 210 respectively form a drag surface 202 and a thrust surface 201 according to the force of the conveyed material. A screw groove is formed between the two screw ribs 210 .

The thrust guide structure 220 and the drag guide structure 230 are arranged periodically starting from the compression section of the screw 200 .

In some embodiments of the present invention, an upper side of one end of the barrel 100 is provided with a material inlet 101 , and the other end is provided with a material outlet 102 . The barrel 100 is sequentially provided with a conveying section 110 , a melting section 120 , a mixing section and a homogenizing section from the feeding port 101 to the feeding port 102 .

In some embodiments of the present invention, the outermost side of the flight 210 abuts against the inner wall of the barrel 100 . A material flow channel 140 is formed between the inner wall of the barrel 100 and the outer surface of the screw 200 .

In some embodiments of the present invention, the thrust guide structure 220 is streamlined, the cross section of the thrust guide structure 220 gradually decreases from the beginning to the end, and the thrust guide structure 220 moves from a side close to the screw 200 to a side away from the screw 200 The sides are gradually narrowed to form the first guide line 221 .

In some embodiments of the present invention, the drag guide structure 230 is streamlined, the cross section of the drag guide structure 230 gradually decreases from the beginning to the end, and the drag guide structure 230 moves from a side close to the screw 200 to a side far away from the screw 200 The sides are gradually narrowed and a second guide line 231 is formed.

In this embodiment, the streamlined thrust guide structure 220 and drag guide structure 230 can effectively reduce the stagnation effect of the fluid and improve the self-cleaning ability of the screw groove.

In some embodiments of the present invention, the angle formed by the first guiding line 221 and the longitudinal flow direction is the first diversion angle α, referring to FIG. 6 , ∠AO ₁ B is α. The angle formed by the second guiding line 231 and the longitudinal flow direction is the second diversion angle β. Referring to FIG. 7 , ∠CO ₂ D is β.

Referring to FIG. 3 , FIG. 3 is a structural diagram of a thrust flow guide structure 220 and a drag flow guide structure 230 in a parallel arrangement. When 0<α<π/2, 0<β<π/2, the single-screw 200 extrusion injection device adopts parallel arrangement.

Referring to FIG. 4 , FIG. 4 is a structural diagram of a thrust diversion structure 220 and a drag diversion structure 230 in reverse arrangement. When π/2<α<π, π/2<β<π, the single-screw 200 extrusion injection device adopts the reverse row method.

Referring to FIG. 5 , FIG. 5 is a structural diagram of a thrust diversion structure 220 and a drag diversion structure 230 in a mixed arrangement. When π/2<α<π, 0<β<π/2, the single-screw 200 extrusion injection device adopts the mixed row method. Or when 0<α<π/2, π/2<β<π, the single-screw 200 extrusion injection device also adopts the mixed row method.

Referring to Fig. 3 , in some embodiments of the present invention, the length of the straight line expanded by the thrust diversion structure 220 is less than πD sinγ/sinα, the length of the straight line expanded by the drag diversion structure 230 is less than πD sinγ/sinβ, and γ is a single screw 200 helicoid 210 helix angle, D is the length of the outer diameter of the screw 200.

In some embodiments of the present invention, the distance connecting two thrust flow guiding structures 220 is S1, and S1 satisfies πD/sin(γ/20)<S1<2πD/sinγ; the distance connecting two dragging flow guiding structures 230 is S2 , S2 satisfies πD/sin(γ/20)<S2<2πD/sinγ.

In some embodiments of the present invention, the distance between adjacent thrust flow guide structures 220 and drag flow guide structures 230 is S3, and S3 satisfies 0≤S3≤4πD/sinγ.

In some embodiments of the present invention, referring to FIG. 6, the height between the beginning of the thrust guide structure 220 and the outer edge of the screw 200 is h1, h1=aD; referring to FIG. The height between the outer edges of the screw is h2, h2=aD; the range of a is 0.0001 to 0.005, and D is the length of the outer diameter of the screw 200.

Referring to FIG. 6 , FIG. 6 is a structural schematic diagram of the thrust guide structure 220 . In some embodiments of the present invention, the thrust guide structure 220 is a triangular prism structure with a triangular cross section. Of course, the same structure can also be adopted for the drag guide structure 230 .

Referring to FIG. 7 , FIG. 7 is a structural schematic diagram of the drag guide structure 230 . In some embodiments of the present invention, the dragging guide structure 230 is a plowlike structure, the first guiding line 221 or the second guiding line 231 is an arc line, and the first guiding line 221 or the second guiding line One side of 231 is a crescent-shaped surface, and the other side of the first guiding wire 221 or the second guiding wire 231 is a paddle-shaped surface. Of course, the same structure can also be adopted for the thrust guide structure 220 .

Referring to FIG. 8 , FIG. 8 is another structural schematic diagram of the drag guide structure 230 . In some embodiments of the present invention, the dragging guide structure 230 is a plowlike structure, and the first guiding line 221 or the second guiding line 231 is an S-shaped arc. Of course, the same structure can also be adopted for the thrust guide structure 220 .

Some embodiments of the present invention provide a plasticizing extrusion method, which uses the above-mentioned single-screw 200 extrusion injection device.

The material enters the barrel 100 from the feed port 101, and the screw 200 rotates around its own axis; under the action of friction, the material moves along the screw groove in the material flow channel 140 to the discharge port 102 and is continuously compacted. The conveying section 110 enters the melting section 120 .

The material entering the melting section 120 continues to move forward along the screw groove under the rotation of the screw 200, and is further compacted to form a solid bed, which is partially melted under the action of external heating and frictional heat generation; the solid bed formed by the material moves along the longitudinal direction of the screw groove. Continuously pushed forward, under the action of the thrust diversion structure 220 and the drag diversion structure 230, the solid bed turns over and migrates along the diversion direction, which accelerates the migration of the melt film, eliminates the blockage of the solid bed, and effectively lifts the the melting efficiency. The molten material continues to be transported forward under the action of friction, and enters the metering section 130, which includes a mixing section and a homogenizing section.

The molten material entering the metering section 130 continues to move forward under the action of the friction force, the thrust diversion structure 220 and the drag diversion structure 230 . The melt is subjected to the tensile force field generated by the thrust diversion structure 220 and the narrow compression gap formed by the drag diversion structure 230 and the side wall of the screw edge 210, which improves the dispersion and mixing efficiency; at the same time, the melt is subjected to the thrust diversion structure 220 The vortex in the expansion plane of the screw groove caused by the drainage of the dragging diversion structure 230, and the cascade vortex effect caused by the local structure of the windward side and the leeward side of the diversion structure effectively strengthen the effect of distribution, dispersion and mixing, and effectively enhance the heat transfer effect , and the melting and plasticizing process of the material is further completed, the extrusion pressure is established, the material is extruded from the discharge port 102, and the extrusion process is completed.

In addition, during material extrusion, the thrust deflector structure 220 and the drag deflector structure 230 start from the side wall of the flight 210 of the screw 200 and adopt a streamlined design, which eliminates stagnation points in the flow channel and effectively improves the flow through longitudinal flow control. The flow scouring action at the root of the screw 200 can effectively improve the self-cleaning function of the device.

Some embodiments of the present invention provide a plasticizing injection method, and the plasticizing extrusion method uses the above-mentioned single-screw 200 extrusion injection device.

The material enters the barrel 100 from the feed port 101 , the screw 200 rotates around its own axis and retreats along the axis of the screw 200 . Under the action of friction, the material is conveyed forward in the material flow channel 140 and continuously compacted, passes through the solid conveying section 110, and enters the melting section 120.

The material entering the melting section 120 continues to move forward along the screw groove under the rotation of the screw 200, and is further compacted to form a solid bed, which is partially melted under the action of external heating and frictional heat generation; the solid bed formed by the material moves along the longitudinal direction of the screw groove. Continuously pushed forward, under the action of the thrust diversion structure 220 and the drag diversion structure 230, the solid bed turns over and migrates along the diversion direction, which accelerates the migration of the melt film and effectively improves the melting efficiency. The molten material continues to be transported forward under the action of friction force and enters the metering section 130 .

The molten material enters the metering section 130 and continues to move forward under the action of the friction force and the thrust diversion structure 220 and the drag diversion structure 230. The tension force field effect generated by the narrow compression gap effect improves the dispersion and mixing efficiency; at the same time, the melt is subjected to the drainage of the thrust diversion structure 220 and the drag diversion structure 230, which causes the vortex in the expansion plane of the screw groove and the diversion The cascade vortex effect caused by the local structure of the windward side and the leeward side of the structure effectively strengthens the effect of distribution, dispersion and mixing, effectively enhances the heat transfer effect, and further completes the melting and plasticizing process of the material. The retreating motion of the screw 200 is continuously conveyed into the cavity formed between the screw 200 and the barrel 100 .

When the screw 200 reaches the limit position of retreat, it moves forward along the axis of the barrel 100 under the action of the external axial thrust, pushing the plasticized melt in front of the screw 200 to be injected from the outlet, realizing the injection movement and completing the plasticizing injection A cycle. Plasticizing injection is a periodic process, and the above process can be repeated after the injection action is completed.

The above descriptions are only preferred embodiments of the present invention, and the present invention is not limited to the above-mentioned embodiments, as long as they achieve the technical effects of the present invention by the same means, they should all belong to the protection scope of the present invention.

Claims

A single-screw extrusion injection device is characterized in that it comprises:

Barrel;

A screw, the screw is located in the barrel, the outer surface of the screw is provided with a spiral flight extending along the axial direction of the screw, and the outer surface of the screw is provided with thrust guide structures arranged alternately and a drag guide structure, the beginning of the thrust guide structure is connected to the thrust surface of the screw flight, the end of the thrust guide structure extends toward the drag surface of the screw flight, and the drag guide structure The starting end is connected to the dragging surface of the screw flight, and the end of the drag guiding structure extends toward the thrust surface of the screw flight, and the thrust guiding structure and the drag guiding structure are connected between the screw flight and the A gap is formed between the inner walls of the barrel, and the thrust flow guide structure and the drag flow guide structure are used to form alternating vortices in the longitudinal flow direction.
A single-screw extrusion injection device according to claim 1, wherein the thrust guide structure is streamlined, the cross section of the thrust guide structure gradually decreases from the beginning to the end, and the thrust guide structure The flow structure gradually narrows from a side close to the screw to a side away from the screw and forms a first guiding line.
The single-screw extrusion injection device according to claim 2, wherein the drag guide structure is streamlined, the cross section of the drag guide structure gradually decreases from the beginning to the end, and the drag guide The flow structure gradually narrows from a side close to the screw to a side away from the screw and forms a second guide line.
A single-screw extrusion injection device according to claim 3, characterized in that, the angle formed by the first guide wire and the longitudinal flow direction is a first diversion angle α, and the second guide wire The angle formed between the lead wire and the longitudinal flow direction is the second diversion angle β, and when 0<α<π/2, 0<β<π/2, the single-screw extrusion injection device adopts a parallel arrangement; When π/2<α<π, π/2<β<π, the single-screw extrusion injection device adopts the reverse arrangement; when 0<α<π/2, π/2<β<π, the single The screw extrusion injection device adopts a mixed arrangement; when π/2<α<π, 0<β<π/2, the single screw extrusion injection device adopts a mixed arrangement.
A single-screw extrusion injection device according to claim 4, characterized in that, the length of the straight-line expansion of the thrust guide structure is less than πD sinγ/sinα, and the length of the straight-line expansion of the drag guide structure is less than πD sinγ/ sinβ, γ is the helix angle of the single-screw flight, and D is the length of the outer diameter of the screw.
A single-screw extrusion injection device according to claim 4, characterized in that, the distance connecting the two thrust guide structures is S1,

S1 satisfies πD/sin(γ/20)<S1<2πD/sinγ;

The distance between the two dragging guide structures is S2,

S2 satisfies πD/sin(γ/20)<S2<2πD/sinγ.
A single-screw extrusion injection device according to claim 6, characterized in that, the distance between the adjacent thrust guide structure and the drag guide structure is S3, and S3 satisfies 0≤S3≤4πD / sin gamma.
A single-screw extrusion injection device according to claim 1, wherein the height between the beginning of the thrust guide structure and the outer edge of the screw is h1, h1=aD; the drag guide The height between the beginning of the flow structure and the outer edge of the screw is h2, h2=aD; the range of a is 0.0001 to 0.005, and D is the length of the outer diameter of the screw.
The single-screw extrusion injection device according to claim 1, wherein the outermost side of the flight is in contact with the inner wall of the barrel.
A single-screw extrusion injection device according to claim 1, characterized in that the barrel includes a conveying section, a melting section, a mixing section and a homogenizing section connected in sequence.