CN117734142A - A screw whose flow channel cross section can be designed parametrically - Google Patents

Abstract

The utility model discloses a screw with a parametrizable flow passage section, which comprises a screw body, screw edges and a flow dividing mixing element; wherein, the parameterized design is carried out on part or all of the sections of the flow channels along the direction of the spiral grooves: the width of the spiral groove is increased, the depth of the spiral groove is reduced, and the depth of the spiral groove is increased, so that mass transfer exists in the width direction of the spiral groove and mass transfer exists in the depth direction of the spiral groove at the same time when mass transfer exists in each flow passage section in the width direction of the spiral groove; part or all of the flow channels gradually converge along the linear change rule of the direction of the spiral grooves, so that the materials are compacted continuously while being sheared and stretched; the flow dividing and mixing element comprises a plurality of flow blocking blocks arranged on the peripheral surface of the rear section of the screw body, and the flow blocking blocks are arranged in a spiral array, so that the material flow passes through the flow dividing and mixing blocks every time the material flow passes through one row of flow blocking blocks. The utility model can solve the problem of insufficient mixing in the melting and plasticizing process of materials and the problem of steam drum in the extrusion melt.

Description

A screw whose flow channel cross section can be designed parametrically

Technical field

The invention relates to the technical field of polymer material processing, and in particular to a screw whose flow channel cross section can be parameterized in design.

Background technique

The screw is the core component of polymer material molding and processing machinery. It mainly transports and plasticizes materials during the molding process. The reasonableness of its structural design has a decisive impact on the production efficiency of the processing process and the quality of molded products. After years of experience, Practical exploration shows that although many new screws with high output and low energy consumption have been designed, there are still some shortcomings such as material accumulation and air entrapment.

According to the structural form of the screw, it can be divided into conventional screws and new screws. Conventional screws usually adopt a three-stage full thread structure. The thread structure mainly adopts a constant pitch variable groove depth or a variable pitch equal groove depth structure to achieve material compression. Due to the structural characteristics of conventional screws However, it can easily lead to deficiencies such as slow material melting, large pressure fluctuations, poor mixing effects, and insufficient plasticization during the extrusion process. In view of the problems of conventional screws, new screws such as separation screws, barrier screws, split flow screws, and variable flow channel screws have been developed and have achieved certain results. Among them, separation screws, barrier screws, and split flow screws are located in different sections of the screw. The solid-melt separation structure is designed to separate the solid from the melt to prevent poor plasticization. At the same time, shear plasticization is mainly used to make the material undergo a long thermo-mechanical process. The corrugated screw is a representative structure of a variable flow channel screw. By changing the flow channel structure design such as the number of wave grooves and the cross-sectional shape of the wave grooves, it can achieve both shear plasticizing and tensile plasticizing effects and reduce the thermomechanical process of the material. Unreasonable flow channel design can easily lead to the existence of bubbles in the extrudate melt, that is, air entrapment.

For example, a double-gradient double-corrugated screw, refer to the patent document. Invention title: double-gradient double-corrugated screw, patent publication number: CN1036922A. The entire screw adopts an eccentric structure to make the groove depth and amplitude change from large to small and then from small to large. The groove width The material remains unchanged, and the plasticizing and mixing of the material is achieved by shearing and stretching. However, the double gradually changing screw also has shortcomings: the eccentric structure achieves a shearing effect on the material and also has a stretching effect to achieve a better melting and plasticizing effect. Since the width of the screw groove remains unchanged, each screw groove section of the material moves along the direction of the screw groove. Only mass transfer occurs along the depth direction of the groove, so the mixing effect is insufficient.

For example, the variable depth double corrugated screw, refer to the patent document utility model name: corrugated screw for injection molding machine, patent publication number: CN203726779U, the melting section adopts an eccentric structure, the solid section and the metering section have variable pitch and flute structures and a tapered flow channel. The screw has shearing and stretching effects to melt and plasticize the material. Similarly, the variable-depth double-wave screw has shortcomings: the melting section adopts an eccentric structure design to achieve shearing and stretching effects on the material. Since the solid section and metering section adopt variable pitch, that is, the flow channel cross section along the direction of the screw groove changes stepwise. Because the sudden change in the cross-section is prone to material accumulation problems, the eccentric structural design also causes air entrapment.

For example, a single corrugated screw, refer to the patent document Utility Model Name: Plastic Molding Screw, Patent Publication Number: CN201685441U. The spiral edge of the screw melting section is a curved structure, the depth of the screw groove remains unchanged, and the width of the screw groove changes periodically along the axial direction. To achieve shearing and stretching, the metering section adopts a pin structure to achieve plasticization and mixing of materials. The disadvantage is that the design of the spiral arc surface that changes periodically along the axial direction of the screw can achieve shearing and stretching effects on the material. However, due to the constant depth of the screw groove, the material moves along the direction of the screw groove. Mass transfer only occurs along the depth direction of the screw groove, and the mixing effect is poor. At the same time, the process of material volume changing from small to large relies on melt expansion to fill the slow cavity. Insufficient expansion is prone to entrapment.

To sum up, there are main problems in the existing technology: 1. Insufficient mixing; 2. The melting process of the material is ignored and proceeds slowly. Solid materials and melt materials of the same mass occupy different volumes, resulting in air entrapment problems.

Contents of the invention

The present invention aims to solve one of the above-mentioned technical problems in the prior art, at least to a certain extent. To this end, embodiments of the present invention provide a screw with a parameterizable design of the flow channel cross section, which solves the problem of insufficient mixing during the melting and plasticizing process of the material and the problem of a steam drum in the extruded melt.

According to the embodiment of the present invention, a screw with a parameterizable design of flow channel cross section includes a screw body, a spiral rib and a split flow mixing element. Several of the spiral ribs are arranged on the peripheral surfaces of the front and middle sections of the screw body, so that There are several flow channels on the screw body, and the cross section of the flow channel is the flow channel cross section; wherein, part or all of the flow channel cross section is designed parametrically along the direction of the screw groove: as the width of the screw channel becomes larger, the screw channel The depth becomes smaller, the width of the groove becomes smaller, and the depth of the groove becomes larger, so that in each of the flow channel sections, there is mass transfer along the width direction of the groove, and there is also mass transfer along the depth direction of the groove. The direction and cross-section direction of the flow channel are consistent with the direction of material flow; part or all of the flow channel exhibits a linear change pattern and gradually converges along the direction of the screw groove, so that while the material is sheared and stretched, the material is also constantly under pressure. Really; the splitting mixing element includes a plurality of flow blocking blocks arranged on the peripheral surface of the rear section of the screw body, and each of the flow blocking blocks is arranged in a spiral array, so that the material flow passes through one row of the blocking blocks. The flow block undergoes one splitting and mixing.

In an optional or preferred embodiment, the helical edge is provided with two first helical edges and a second helical edge respectively, and the rear edge of the first helical edge and the front edge of the second helical edge form a third helical edge. A first flow channel, the cross section of the first flow channel is the first flow channel cross section, the front edge of the first helical edge and the rear edge of the second helical edge form a second flow channel, the cross section of the second flow channel is A second flow channel cross section. The flow channel includes the first flow channel and the second flow channel. The first flow channel has a groove width of W1 and a groove depth of H1. The second flow channel has a groove width of W1 and a groove depth of H1. The groove width is W2 and the screw groove depth is H2. The entire screw, whose flow channel cross section can be parameterized, is divided into three sections from the front section to the rear section, including a solid conveying section, a melting section and a metering section. The solid conveying section includes solid There is a front conveying section and a rear solid conveying section, and the metering section includes a front metering section and a rear metering section.

In an optional or preferred embodiment, in the solid conveying front section, both the first flow channel cross section and the second flow channel cross section remain unchanged. Further, in the solid conveying front section, the thickness of the first spiral edge and the second spiral edge remain unchanged, and the depth of the spiral groove of the first flow channel and the second flow channel remains unchanged.

In an optional or preferred embodiment, in the solid conveying rear section, the melting section and the metering front section, the flow channel cross section is designed parametrically along the direction of the screw groove.

Wherein, in the latter section of solid conveying, the first helical edge and the second helical edge are designed with equal pitch, and the first flow channel cross section and the second flow channel cross section continue according to a linear rule along the direction of the screw groove. Reduced; while the groove depth H1 of the first flow channel changes according to the sinusoidal law, its groove width W1 changes according to the cosecant law, and the groove depth H2 and groove width W2 of the second flow channel change according to the law of H1 respectively. , W2 are the same, and the phase difference is 180°.

Wherein, in the melting section, the first helical edge and the second helical edge are designed with equal pitch, and the first flow channel cross section and the second flow channel cross section continue to shrink linearly along the direction of the screw groove; The groove depth H1 of the first flow channel adopts a sinusoidal change rule with a smaller amplitude and multiple periods, while the groove width W1 changes according to the cosecant law. The groove depth H2 and the groove width W2 of the second flow channel are The changing rules are the same as H1 and W2 respectively, and the phase difference is 180°.

Wherein, in the pre-measuring section, the first spiral edge and the second spiral edge are designed with equal pitch, and the first flow channel cross section and the second flow channel cross section remain unchanged along the screw groove direction; The groove depth H1 of the first flow channel adopts a constant-amplitude multi-period sinusoidal variation law, while its groove width W1 changes according to a cosecant law. The groove depth H2 and groove width W2 of the second flow channel change with the same rules respectively. H1 and W2 are the same, and the phase difference is 180°.

In an optional or preferred embodiment, the split mixing element is provided in the post-metering section. further,

In the diversion mixing element, the flow blocking blocks are prismatic. Each time the material flow passes through one row of the flow blocking blocks, it undergoes one splitting and mixing. After passing through n rows of flow blocking blocks, the material flow undergoes 2 ⁿ splitting operations. and confluence.

Based on the above technical solution, the embodiments of the present invention at least have the following beneficial effects: In the above technical solution, part or all of the flow channels gradually converge along the spiral direction, the cross section of the flow channel continuously shrinks along the spiral direction, and the material flows along the flow channel process. The velocity gradient is generated in the direction, and the material flow process is subject to shearing and stretching, thus reducing the mechanical thermal history of the material. At the same time, due to the convergence of the flow channel, the material is continuously compacted and the air entrapment phenomenon is eliminated; parametric design is carried out The cross section of the flow channel has a periodic change in the direction of the groove depth and the groove width, which increases the mass transfer effect of the material during the flow process and improves the screw mixing effect.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and examples;

Figure 1 is a schematic structural diagram of an embodiment of the present invention;

Figure 2 is a cross-sectional view along the A-A direction in Figure 1;

Figure 3 is a cross-sectional view along the B-B direction in Figure 1;

Figure 4 is a cross-sectional view along the C-C direction in Figure 1;

Figure 5 is an expanded schematic view of the splitter mixing element in the embodiment of the present invention;

Figure 6 is a schematic diagram of the change pattern of the flow channel cross section in the embodiment of the present invention;

Figure 7 is a schematic diagram of the change pattern of the depth of the flow channel groove in the embodiment of the present invention;

Figure 8 is a schematic diagram of the change pattern of the width of the flow channel groove in the embodiment of the present invention;

Figure 8 is a schematic diagram of the change pattern of the width of the flow channel groove in the embodiment of the present invention;

Figure 9 is a schematic view of the expansion of the screw channel material in the embodiment of the present invention.

Detailed ways

This section will describe the specific embodiments of the present invention in detail. The preferred embodiments of the present invention are shown in the accompanying drawings. The function of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand the present invention. Each technical feature and overall technical solution of the invention shall not be construed as limiting the scope of protection of the invention.

In the description of the present invention, it should be understood that orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or position relationships shown in the drawings and are only In order to facilitate the description of the present invention and simplify the description, it is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as a limitation of the present invention.

In the description of the present invention, several means one or more, plural means two or more, greater than, less than, more than, etc. are understood to exclude the original number, and above, below, within, etc. are understood to include the original number. If there is a description of first and second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features. relation.

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

Referring to Figures 1 to 9, a screw with a parameterizable design of the flow channel cross section is shown, including a screw body 100, a spiral edge and a split flow mixing element 300. Several spiral edges are provided and are arranged around the front and middle sections of the screw body 100. On the surface, there are several flow channels on the screw body 100, and the cross section of the flow channel is the flow channel cross section.

In this embodiment, the screw body has a diameter of 30, an aspect ratio of 28, and a compression ratio of 3.0.

Among them, part or all of the flow channel cross-sections are designed parametrically along the direction of the screw groove: as the screw channel width becomes larger, the screw groove depth becomes smaller, and as the screw channel width becomes smaller, the screw groove depth becomes larger, so that each flow channel section While there is mass transfer along the width direction of the screw channel, there is also mass transfer along the depth direction of the screw channel. The direction of the screw channel and the direction of the flow channel section are consistent with the direction of material flow.

Part or all of the flow channel gradually converges linearly along the direction of the screw groove, so that while the material is sheared and stretched, the material is also continuously compacted.

Specifically, referring to Figure 1, the entire flow channel cross-section of the screw can be parameterized and designed into three sections from the front section to the rear section, including the solid conveying section P1, the melting section P2 and the metering section P3. The solid conveying section P1 includes the solid conveying front section P11. and the solid conveying rear section P12, and the metering section P3 includes the pre-measurement section P31 and the post-measurement section P32.

Two helical edges are provided, namely the first helical edge E1 and the second helical edge E2. As shown in Figure 2, the first helical edge E1 and the second helical edge E2 are of equal pitch, but the thickness of the helical edge changes. The rear edge of the first helical edge E1 and the front edge of the second helical edge E2 form a first flow channel S1. The cross section of the first flow channel S1 is the first flow channel cross section. The front edge of the first helical edge E1 and the front edge of the second helical edge E2 The rear edge forms a second flow channel S2. The cross section of the second flow channel S2 is the second flow channel cross section. The flow channel includes a first flow channel S1 and a second flow channel S2. The groove width of the first flow channel S1 is W1. The depth is H1, the groove width of the second flow channel S2 is W2, and the groove depth is H2, as shown in Figures 3 and 4.

In the solid conveying front section P11, in order to ensure continuous conveying of the same amount of solid materials, the first flow channel cross-section and the second flow channel cross-section remain unchanged. It can be understood that the thickness of the first helical edge E1 and the second helical edge E2 remains unchanged, and the groove depths of the first flow channel S1 and the second flow channel S2 remain unchanged, that is, the structure of equal groove depth and equal pitch, The screw groove widths W1 and W2 and the screw groove depths H1 and H2 are constants.

In the solid conveying rear section P12, the melting section P2, and the metering front section P31, the flow channel section is designed parametrically along the direction of the screw channel, that is, when the screw channel width becomes larger, the screw channel depth becomes smaller, and when the screw channel width becomes smaller, the channel depth becomes smaller. The depth becomes greater.

In the final section P12 of solid conveying, in order to ensure material compaction and gas discharge between materials, the first spiral edge E1 and the second spiral edge E2 are designed with equal pitch, and the first and second flow channel sections are arranged along the direction of the screw groove. The linear law continues to shrink; in order to increase the mixing and mass transfer effects of the material width direction and depth direction in the flow channel section, the groove depth H1 of the first flow channel S1 changes according to the sinusoidal law, while its groove width W1 changes according to the cosecant law, The change rules of the groove depth H2 and the groove width W2 of the second flow channel S2 are the same as those of H1 and W2 respectively, and the phase difference is 180°. The changing pattern of the depth and width of the screw groove in this section requires writing a specific program to control it.

In the melting section P2, in order to reduce the thermal history of the material and compact the exhaust, the first spiral edge E1 and the second spiral edge E2 are designed with equal pitch, and the first flow channel section and the second flow channel section continue according to a linear law along the direction of the screw groove. reduction; in order to ensure the mixing and compaction effect, the groove depth H1 of the first flow channel S1 adopts a sinusoidal change rule with a smaller amplitude for multiple periods, while its groove width W1 changes according to the cosecant law, and the screw groove depth H1 of the second flow channel S2 changes according to the cosecant law. The change rules of groove depth H2 and screw groove width W2 are the same as H1 and W2 respectively, and the phase difference is 180°. The changing rules of the depth and width of the screw groove in this section need to be controlled by writing a specific program.

In the pre-measurement section P31, in order to ensure stable transportation, the first spiral edge E1 and the second spiral edge E2 are designed with equal pitch, and the first flow channel cross section and the second flow channel cross section remain unchanged along the screw groove direction; in order to further enhance the mixing effect , the groove depth H1 of the first flow channel S1 adopts a constant-amplitude multi-period sinusoidal variation law, while its groove width W1 changes according to the cosecant law, and the groove depth H2 and groove width W2 of the second flow channel S2 vary according to the law respectively. Same as H1 and W2, the phase difference is 180°. The changing rules of the depth and width of the screw groove in this section need to be controlled by writing a specific program 3.

The split mixing element 300 is provided in the post-metering section P32. Specifically, referring to Figure 5, the splitting mixing element 300 includes a plurality of flow blocking blocks 301 arranged on the peripheral surface of the rear section of the screw body 100. Each flow blocking block 301 is arranged in a spiral array, so that the material flow passes through a row of blocking blocks 301. Block 301 undergoes splitting and mixing once, which can further improve the mixing effect and eliminate pressure fluctuations. Specifically, as shown in Figure 5, the flow blocking blocks 301 are prismatic. Each time the material flow passes through a row of flow blocking blocks 301, it undergoes one splitting and mixing. After passing through n rows of flow blocking blocks, the material flow undergoes 2 ⁿ splitting operations. and confluence.

The flow channels in the rear section P12 and the melting section P2 of the screw solid conveying section P12 and the melting section P2 of which the above-mentioned flow channel cross sections can be parameterized are gradually converged along the direction of the screw groove. The cross section of the flow channel is continuously reduced along the spiral direction. The material is generated along the flow direction during the flow channel process. Due to the velocity gradient, the material flow process is subject to shearing and stretching, thus reducing the mechanical thermal history of the material. At the same time, due to the convergence of the flow channel, the material is continuously compacted and the air entrapment phenomenon is eliminated. The solid conveying back section P12, the melting section P2, and the metering front section P31 are flow channel cross-sections designed with parametric design. The depth of the groove and the width of the groove change periodically, as shown in Figure 9, so that the material flows The process increases its mass transfer effect and improves the screw mixing effect.

It should be noted that in actual operations, specific personnel in the field can perform parametric design on the specific flow channel section of the screw body along the direction of the screw groove, and at which flow channel section the linear change rule gradually converges. This field can Adaptive adjustments are generally made at the mid-section and adjusted appropriately.

In this embodiment, in the solid conveying rear section P12, the changing rules of the groove depth and the groove width of the flow channel are controlled according to a specific program 1. The specific program 1 includes the first flow channel section S1, the second flow channel section S1 of the solid conveying rear section P12. Road section S2 control program, specifically:

H1＝1*sin(trajpar*360*2)+6;

W1＝(-1*(4*trajpar+3)+73)/(1*sin(trajpar*360*2)+6);

H2＝-1*sin(trajpar*360*2)+6;

W2=(-1*(4*trajpar+3)+73)/(-1*sin(trajpar*360*2)+6).

In the melting section P2, the change rules of the groove depth and groove width of the runner are controlled according to a specific program 2. The specific program 2 includes the first runner cross-section S1 control program 1 of the melting section P2, specifically:

H1＝0.5*sin(trajpar*360*1)+6;

W1＝(-3.90909*(2*trajpar+7)+93.36364)/(0.5*sin(trajpar*360*1)+6);

First flow channel section S1 control program 2:

H1＝-1.5*trajpar+6;

W1＝(-3.90909*(0.5*trajpar+9)+93.36364)/(-1.5*trajpar+6);

First flow channel section S1 control program 3:

H1＝0.3*sin(trajpar*360*1)+4.5;

W1＝(-3.90909*(2*trajpar+9.5)+93.36364)/(0.3*sin(trajpar*360*1)+4.5);

First flow channel section S1 control program 4:

H1＝-0.9*trajpar+4.5;

W1＝(-3.90909*(0.5*trajpar+11.5)+93.36364)/(-0.9*trajpar+4.5);

First flow channel section S1 control program 5:

H1＝0.4*sin(trajpar*360*1.5)+3.6;

W1＝(-3.90909*(3*trajpar+12)+93.36364)/(0.4*sin(trajpar*360*1.5)+3.6);

First flow channel section S1 control program 6:

H1＝-1.1*trajpar+3.6;

W1＝(-3.90909*(0.5*trajpar+15)+93.36364)/(-1.1*trajpar+3.6);

First flow channel section S1 control program 7:

H1＝0.3*sin(trajpar*360*1)+2.5;

W1＝(-3.90909*(2*trajpar+15.5)+93.36364)/(0.3*sin(trajpar*360*1)+2.5); First flow channel section S1 control program 8:

H1＝-0.6*trajpar+2.5;

W1＝(-3.90909*(0.5*trajpar+17.5)+93.36364)/(-0.6*trajpar+2.5);

Second flow channel section S2 control program 1 of melting section P2:

H2＝-0.5*sin(trajpar*360*1)+6;

W2＝(-3.90909*(2*trajpar+7)+93.36364)/(-0.5*sin(trajpar*360*1)+6);

Second flow channel section S2 control program 2:

H2＝-1.5*trajpar+6;

W2＝(-3.90909*(0.5*trajpar+9)+93.36364)/(-1.5*trajpar+6);

Second flow channel section S2 control program 3:

H2＝-0.3*sin(trajpar*360*1)+4.5;

W2＝(-3.90909*(2*trajpar+9.5)+93.36364)/(-0.3*sin(trajpar*360*1)+4.5); Second flow channel section S2 control program 4:

H2 = -0.9*trajpar+4.5;

W2＝(-3.90909*(0.5*trajpar+11.5)+93.36364)/(-0.9*trajpar+4.5);

Second flow channel section S2 control program 5:

H2＝0.4*sin(trajpar*360*1.5)+3.6;

W2＝(-3.90909*(3*trajpar+12)+93.36364)/(0.4*sin(trajpar*360*1.5)+3.6); Second flow channel section S2 control program 6:

H2＝-1.1*trajpar+3.6;

W2＝(-3.90909*(0.5*trajpar+15)+93.36364)/(-1.1*trajpar+3.6);

Second flow channel section S2 control program 7:

H2＝-0.3*sin(trajpar*360*1)+2.5;

W2＝(-3.90909*(2*trajpar+15.5)+93.36364)/(-0.3*sin(trajpar*360*1)+2.5);

Second flow channel section S2 control program 8:

H2＝-0.6*trajpar+2.5;

W2=(-3.90909*(0.5*trajpar+17.5)+93.36364)/(-0.6*trajpar+2.5).

In the pre-measurement section P31, the change rules of the groove depth and groove width of the flow channel are controlled according to specific program 3. The specific program 3 includes the control procedures for the first flow channel section S1 and the second flow channel section S2 in the pre-measurement section, specifically:

H1＝0.1*sin(trajpar*360*4.5)+1.9;

W1＝23/(0.1*sin(trajpar*360*4.5)+1.9);

H2＝-0.1*sin(trajpar*360*4.5)+1.9;

W2＝23/(-0.1*sin(trajpar*360*4.5)+1.9).

The above-mentioned specific program 1, specific program 2 and specific program 3 are a specific embodiment of the parametric design of the control flow channel section of the present invention. In other embodiments, other control programs can also be used, as long as the following conditions are met: Part or all of the flow channel cross-section is designed parametrically along the direction of the screw groove. When the screw channel width becomes larger, the screw channel depth becomes smaller, and when the screw channel width becomes smaller, the screw groove depth becomes larger; and part or all of the flow channel is realized at the same time. The linear change pattern along the screw groove direction gradually converges.

The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the technical field, various modifications can be made without departing from the purpose of the present invention. kind of change.

Claims (10)

1. The screw with the parametrizable flow passage section is characterized by comprising a screw body, screw edges and a flow dividing mixing element, wherein the screw edges are arranged on the peripheral surfaces of the front section and the middle section of the screw body, so that the screw body is provided with a plurality of flow passages, and the section of each flow passage is a flow passage section; wherein,

and carrying out parameterized design on part or all of the sections of the flow channels along the direction of the spiral grooves: the width of the spiral groove is increased, the depth of the spiral groove is reduced, and the depth of the spiral groove is increased, so that mass transfer exists in the width direction of the spiral groove and mass transfer exists in the depth direction of the spiral groove at the same time when mass transfer exists in each flow channel section, and the directions of the spiral groove and the flow channel section are consistent with the flow direction of materials;

part or all of the flow channels gradually converge along the direction of the spiral grooves in a linear change rule, so that the materials are compacted continuously while being sheared and stretched;

the flow dividing and mixing element comprises a plurality of flow blocking blocks arranged on the peripheral surface of the rear section of the screw body, and the flow blocking blocks are arranged in a spiral array, so that a material flow is divided and mixed once after passing through each row of flow blocking blocks.

2. The screw of claim 1, wherein the flow channel cross section is parametrizable, characterized by: the screw edges are provided with a first screw edge and a second screw edge respectively, the rear edge of the first screw edge and the front edge of the second screw edge form a first flow channel, the section of the first flow channel is a first flow channel section, the front edge of the first screw edge and the rear edge of the second screw edge form a second flow channel, the section of the second flow channel is a second flow channel section, the flow channels comprise the first flow channel and the second flow channel, the screw rod with the section capable of being parametrically designed is divided into a solid conveying section, a melting section and a metering section from a front section to a rear section, wherein the solid conveying section comprises a solid conveying front section and a solid conveying rear section, and the metering section comprises a metering front section and a metering rear section; wherein,

in the solids conveying forward section, both the first flow passage cross section and the second flow passage cross section remain unchanged;

the flow channel section is parametrically designed along the direction of the spiral groove in the solid conveying rear section, the melting section and the metering front section;

the split mixing element is disposed in the metering rear section.

3. The screw of claim 2, wherein the flow passage cross section is parametrizable, characterized by: in the solid conveying front section, the thicknesses of the first screw edges and the second screw edges are unchanged, and the screw groove depths of the first flow channel and the second flow channel are unchanged.

4. The screw of claim 2, wherein the flow passage cross section is parametrizable, characterized by: in the solid conveying rear section, the first screw thread and the second screw thread are designed with equal screw pitches, and the section of the first flow channel and the section of the second flow channel are continuously reduced along the direction of the screw grooves according to a linear rule; the spiral groove depth H1 of the first flow channel changes according to a sine rule and the spiral groove width W1 of the first flow channel changes according to a complementary cutting rule, the spiral groove depth H2 and the spiral groove width W2 of the second flow channel change according to the same rules as H1 and W2 respectively, and the phase difference is 180 degrees.

5. The screw with parametrizable flow channel cross section according to claim 4, wherein the variation of the channel depth and the channel width in the solid conveying back section is controlled according to a specific program 1, wherein the specific program 1 comprises

The first flow passage section and the second flow passage section of the solid conveying rear section control program:

H1＝1*sin(trajpar*360*2)+6；

W1＝(-1*(4*trajpar+3)+73)/(1*sin(trajpar*360*2)+6)；

H2＝-1*sin(trajpar*360*2)+6；

W2＝(-1*(4*trajpar+3)+73)/(-1*sin(trajpar*360*2)+6)。

6. the screw of claim 2, wherein the flow passage cross section is parametrizable, characterized by: in the melting section, the first screw flight and the second screw flight are designed with equal screw pitches, and the section of the first flow channel and the section of the second flow channel are continuously reduced along the direction of the screw grooves according to a linear rule; the spiral groove depth H1 of the first flow channel adopts a sine change rule with a plurality of periods of smaller amplitude, the spiral groove width W1 of the first flow channel changes according to a complementary cutting rule, the change rule of the spiral groove depth H2 and the spiral groove width W2 of the second flow channel is respectively the same as H1 and W2, and the phase difference is 180 degrees.

7. The screw with parametrizable flow channel cross section according to claim 6, wherein the variation of the groove depth and the groove width of the flow channel in the melting section is controlled according to a specific program 2, wherein the specific program 2 comprises

First flow channel section control procedure 1 for the melt section:

H1＝0.5*sin(trajpar*360*1)+6；

W1＝(-3.90909*(2*trajpar+7)+93.36364)/(0.5*sin(trajpar*360*1)+6)；

first flow passage section control program 2:

H1＝-1.5*trajpar+6；

W1＝(-3.90909*(0.5*trajpar+9)+93.36364)/(-1.5*trajpar+6)；

first flow passage section control program 3:

H1＝0.3*sin(trajpar*360*1)+4.5；

w1= (-3.90909 x (2 x trajpar+9.5) + 93.36364)/(0.3 x sin (trajpar x 360 x 1) +4.5); first flow passage section control program 4:

H1＝-0.9*trajpar+4.5；

W1＝(-3.90909*(0.5*trajpar+11.5)+93.36364)/(-0.9*trajpar+4.5)；

first flow passage section control program 5:

H1＝0.4*sin(trajpar*360*1.5)+3.6；

w1= (-3.90909 x (3 x trajpar+12) + 93.36364)/(0.4 x sin (trajpar x 360 x 1.5) +3.6); first flow passage section control program 6:

H1＝-1.1*trajpar+3.6；

W1＝(-3.90909*(0.5*trajpar+15)+93.36364)/(-1.1*trajpar+3.6)；

first flow passage section control program 7:

H1＝0.3*sin(trajpar*360*1)+2.5；

w1= (-3.90909 x (2 x trajpar+15.5) + 93.36364)/(0.3 x sin (trajpar x 360 x 1) +2.5); first flow passage section control program 8:

H1＝-0.6*trajpar+2.5；

W1＝(-3.90909*(0.5*trajpar+17.5)+93.36364)/(-0.6*trajpar+2.5)；

second flow path cross section control procedure 1 for the melt section:

H2＝-0.5*sin(trajpar*360*1)+6；

w2= (-3.90909 x (2 x trajpar+7) + 93.36364)/(0.5 x sin (trajpar x 360 x 1) +6); second flow passage section control program 2:

H2＝-1.5*trajpar+6；

W2＝(-3.90909*(0.5*trajpar+9)+93.36364)/(-1.5*trajpar+6)；

second flow passage section control program 3:

H2＝-0.3*sin(trajpar*360*1)+4.5；

w2= (-3.90909 x (2 x trajpar+9.5) + 93.36364)/(-0.3 x sin (trajpar x 360 x 1) +4.5); second flow passage section control program 4:

H2＝-0.9*trajpar+4.5；

W2＝(-3.90909*(0.5*trajpar+11.5)+93.36364)/(-0.9*trajpar+4.5)；

second flow passage section control program 5:

H2＝0.4*sin(trajpar*360*1.5)+3.6；

W2＝(-3.90909*(3*trajpar+12)+93.36364)/(0.4*sin(trajpar*360*1.5)+3.6)；

second flow passage section control program 6:

H2＝-1.1*trajpar+3.6；

W2＝(-3.90909*(0.5*trajpar+15)+93.36364)/(-1.1*trajpar+3.6)；

second flow passage section control program 7:

H2＝-0.3*sin(trajpar*360*1)+2.5；

W2＝(-3.90909*(2*trajpar+15.5)+93.36364)/(-0.3*sin(trajpar*360*1)+2.5)；

second flow passage section control program 8:

H2＝-0.6*trajpar+2.5；

W2＝(-3.90909*(0.5*trajpar+17.5)+93.36364)/(-0.6*trajpar+2.5)。

8. the screw of claim 2, wherein the flow passage cross section is parametrizable, characterized by: in the metering front section, the first screw thread and the second screw thread are designed with equal screw pitches, and the first flow passage section and the second flow passage section are kept unchanged along the direction of the screw grooves; the spiral groove depth H1 of the first flow channel adopts a constant-amplitude multicycle sine change rule, the spiral groove width W1 of the first flow channel changes according to a complementary cutting rule, the change rule of the spiral groove depth H2 and the spiral groove width W2 of the second flow channel is respectively the same as H1 and W2, and the phase difference is 180 degrees.

9. The screw of claim 8, wherein the flow channel cross section is parametrizable, characterized by: in the metering front section, the change rule of the screw groove depth and the screw groove width of the flow channel is controlled according to a specific program 3, wherein the specific program 3 comprises

The first flow passage section and the second flow passage section of the metering front section control program:

H1＝0.1*sin(trajpar*360*4.5)+1.9；

W1＝23/(0.1*sin(trajpar*360*4.5)+1.9)；

H2＝-0.1*sin(trajpar*360*4.5)+1.9；

W2＝23/(-0.1*sin(trajpar*360*4.5)+1.9)。

10. the screw of claim 2, wherein the flow passage cross section is parametrizable, characterized by: in the flow dividing and mixing element, the flow blocking blocks are prismatic, the material flow passes through one flow dividing and mixing for each row of the flow blocking blocks, and the material flow passes through 2 rows of the flow blocking blocks ⁿ The secondary branches and merges.