Method for manufacturing a twin screw, twin screw and extruder

Abstract

The embodiment of the present application provides a kind of double screw manufacturing method, double screw and extruder, it is related to but not only limited to extruder equipment technical field, manufacturing method includes according to the center distance determines the first line diameter and the number of first line diameter that are inserted in the first interspersed region formed by a group of adjacent root diameter and top diameter on the first cross section of first screw;According to the first curve segment calculation formula and the central angle calculation formula, determine the first curve segment set arranged on the first screw;According to the first central angle of each third curve segment of first curve segment set, determine the second central angle of each first circular arc segment in first circular arc segment set;Determine the second curve segment set corresponding to first curve segment set and the second circular arc segment set corresponding to first circular arc segment set on the second screw.The first screw and the second screw are respectively manufactured according to first curve segment set, first circular arc segment set, second curve segment set and second circular arc segment set.The embodiment of the present application can improve the promotion effect of mixing on axial flow.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of extruder equipment, in particular to a manufacturing method of a double screw, the double screw and an extruder. BACKGROUND

[0002] In the process of polymer material processing, the differential speed co-rotating double screw extruder is one of the most commonly used devices for mixing high polymers and composite materials. Because the flow body of the high polymer in the extrusion process of the double screw extruder advances along the spiral, the movement mode of the fluid generates periodic flow due to the rotation of the screw, and the exchange flow of the two screws in the meshing intersection area. Due to the spiral configuration of the screw, the axial dragging effect of the transport unit is generated in the rotation process, and the axial circulation movement of the melt caused by the pressure gradient enhances the mixing effect of the fluid, especially the axial enhancement at the position far away from the meshing area. However, the structures of the two screws of most existing co-rotating double screw extruders are completely consistent, and the rotation speeds of the two screws are also the same in the processing process of the material. Due to the same structure of the two screws, the consistency of the geometric space experienced by the fluid in the forward process of the two screws is caused, the conversion of the geometric shape in the forward process of the fluid is lacked, the effect of the shearing process is weakened, and the melting mixing effect is limited. Therefore, the existing double screw technology is poor in promoting the mixing effect in the axial flow. Therefore, it is urgent to provide a double screw structure capable of improving the promoting effect of the mixing in the axial flow. SUMMARY

[0003] The main purpose of the embodiment of the application is to provide a manufacturing method of a double screw, the double screw and an extruder, which aims to improve the promoting effect of the mixing in the axial flow.

[0004] Determine the root diameter, the top diameter, the rotation speed ratio of the first screw and the second screw, and the center distance between the first screw and the second screw;

[0005] According to the center distance, determine the first wire diameter and the number of the first wire diameters inserted in the first insertion area formed by a group of adjacent root diameters and top diameters on the first cross section of the first screw;

[0006] According to a preset central angle calculation formula and a first curve segment calculation formula, determine a first curve segment set arranged on the first screw, wherein the first curve segment set is composed of a plurality of first curve segments obtained by inserting the first wire diameters in the first insertion area and a second curve segment formed by another group of adjacent root diameters and top diameters;

[0007] According to the first central angle corresponding to each third curve segment of the first curve segment set, determine the second central angle of each first arc segment of the first arc segment set arranged on the first cross section;

[0008] According to the first curve segment set and the first circular arc segment set, a first screw rod is manufactured;

[0009] A second curve segment set corresponding to the first curve segment set and a second circular arc segment set corresponding to the first circular arc segment set are determined on the second screw rod, wherein a ratio of a central angle of each fourth curve segment in the second curve segment set to a corresponding third curve segment is the rotation speed ratio, and a ratio of a central angle of each second circular arc segment in the second circular arc segment set to a corresponding first circular arc segment is the rotation speed ratio;

[0010] According to the second curve segment set and the second circular arc segment set, a second screw rod is manufactured.

[0011] According to some embodiments of the second aspect of the present application, an extruder comprises:

[0012] A barrel, an inner cavity of the barrel is provided as two intersecting cylindrical grooves;

[0013] A double screw rod, the double screw rod is manufactured by the method as described in any of the first aspect, a first screw rod of the double screw rod is located in one of the cylindrical grooves, and a second screw rod of the double screw rod is located in the other cylindrical groove.

[0014] The manufacturing method of the double screw rod, the double screw rod and the extruder provided by the present application set a plurality of first curve segments between a group of adjacent root diameters and top diameters of the first screw rod and set second curve segments between another group of adjacent root diameters and top diameters, so that the first screw rod is asymmetric and the cross-sectional area of the first screw rod is increased, so that a wedge-shaped space is formed between the first screw rod and the inner side wall of the containing cavity containing the first screw rod and the wedge-shaped space shows a downward or upward trend with the rotation of the first screw rod. At the same time, the first curve segment set is determined by the central angle calculation formula and the first curve segment calculation formula, and the second curve segment set corresponding to the first curve segment set and the first circular arc segment set and the second circular arc segment set are set on the second screw rod, so that the meshing points of the first screw rod and the second screw rod rotating in the same direction at different speeds are more complex, so that the material is subjected to stronger disturbance and mixing effect. Therefore, compared with related technologies, the double screw rod provided by the present application can provide more complex meshing tracks during movement, and because the cross-sectional area of the first screw rod and the second screw rod is increased, a wedge-shaped pressurizing extrusion stretching action is generated near the thrust surface or the trailing surface of the first screw rod and the second screw rod, so that the converging material in the lower meshing area is further extruded and stretched, and enters the next screw groove. At the same time, this wedge-shaped pressurizing action can further improve the dispersion and mixing capacity. Therefore, the embodiments of the present application can improve the promotion effect of mixing in the axial flow. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a flowchart of the manufacturing method of the double screw rod provided by the embodiments of the present application;

[0016] Figure 2 This is a schematic diagram of the twin-screw mechanism during engagement, as provided in an embodiment of this application.

[0017] Figure 3 This is a schematic diagram illustrating the cross-section of a twin-screw rotor with a speed ratio of 2:1, as provided in the embodiments of this application.

[0018] Figure 4 This is an embodiment of the present application. Figure 3 The cross-sectional view of the twin-screw is shown below;

[0019] Figure 5 This is a schematic diagram illustrating the cross-section of a twin-screw rotor in another embodiment of the present application, where the rotational speed ratio is 2:1.

[0020] Figure 6 This is a schematic diagram comparing the internal cavity volume of two examples of twin-screws manufactured in the embodiments of this application with that of a conventional screw;

[0021] Figure 7 This is a graph showing the relationship between the sum of the apex and base angles of the twin-screw manufactured according to an embodiment of this application and the number of the first curve segments;

[0022] Figure 8 This is a schematic diagram of the motion trajectory of the meshing point of the twin screw manufactured in the embodiments of this application;

[0023] Figure 9 This is a schematic diagram of the motion trajectory of the traditional twin-screw technology and the meshing point;

[0024] Figure 10 It is produced according to the embodiments of this application. Figure 3 A schematic diagram of the longitudinal section of the first screw in a twin-screw screw;

[0025] Figure 11 It is produced according to the embodiments of this application. Figure 5 A schematic diagram of the longitudinal section of the first screw in a twin-screw screw;

[0026] Figure 12 A cross-sectional schematic diagram of the extruder provided in this application.

[0027] Figure label:

[0028] Barrel 100, conveyor section 110, feed inlet 111, melting section 120, venting section 130, vent outlet 131, compounding and extrusion section 140, discharge outlet 141.

[0029] First screw 210, second screw 220

[0030] Flow channel 300. Detailed Implementation

[0031] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to limit the present application.

[0034] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the technology can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to limit the present application.

[0036] Referring to Figure 1 and Figure 2 As shown, the manufacturing method comprises:

[0037] Step S100, determining the root diameter, the top diameter, the speed ratio of the first screw 210 and the second screw 220, and the center distance between the first screw 210 and the second screw 220.

[0038] It should be noted that the speed ratio is an irreducible number, such as the speed ratio is 1:3, or 2:3 or 2:1.

[0039] It should be noted that the root diameter and the top diameter of the first screw 210 and the second screw 220 are the same.

[0040] Step S200: Determine the first wire diameter and the number of the first wire diameters interpolated within the first interpolation region formed by a set of adjacent root diameters and tip diameters on the first cross-section of the first screw 210 according to the center distance.

[0041] It should be noted that the first wire diameter in the first screw 210 is a transition wire diameter, and one end of the first wire diameter is the center of the first screw 210. Since the first screw 210 and the second screw 220 are always meshed, there is a second wire diameter corresponding to the first wire diameter in the second screw 220. At this time, by using the center distance to determine the length of the first wire diameter, the confirmation of the first wire diameter is simpler. Assume that there are k wire diameters interpolated within the first interpolation region. For each wire diameter, it satisfies the following expression: r < R l1 <... < R lk < R, where r is the root diameter and R is the tip diameter.

[0042] Step S300: Determine the first curve segment set provided on the first screw 210 according to the preset central angle calculation formula and the first curve segment calculation formula. The first curve segment set is composed of multiple first curve segments interpolated by the first wire diameter within the first interpolation region and a second curve segment formed by another set of adjacent root diameters and tip diameters.

[0043] It should be noted that when determining the first wire diameter, only the number of the first curve segments interpolated within the first interpolation region can be determined. The central angle calculation formula is used to calculate the first central angle of each first curve segment and the second curve segment, and the first curve segment calculation formula is used to determine the polar radius of each first curve segment and the polar radius of the second curve segment. Therefore, through the central angle calculation formula and the first curve segment calculation formula, the central angle and the polar radius of the first curve segment and the second curve segment can be further clarified.

[0044] It should be noted that the number of the second curve segments is one, and the number of the first curve segments can be obtained through multiple experiments or determined based on the relationship between the first curve segments shown and the sum of the angles that can be allocated to the top angle and the bottom angle (i.e., the central angles corresponding to the root diameter and the tip diameter). Exemplarily, referring to Figure 7 shown, when there are 2 first curve segments, the remaining 131.24° can be allocated to the top angle and the bottom angle. When there are [number of first curve segments] first curve segments, the remaining 47.16° can be allocated to the top angle and the bottom angle, and so on. Figure 7 shown, when there are 2 first curve segments, the remaining 131.24° can be allocated to the top angle and the bottom angle. When there are [number of first curve segments] first curve segments, the remaining 47.16° can be allocated to the top angle and the bottom angle, and so on.

[0045] Exemplarily, referring to Figure 4 shown, within the first interpolation region O1A0A7 of Figure 4 , 3 first wire diameters with different lengths are interpolated, and the obtained first curve segments are A0A1, A2A3, A4A5, A6A7, and the corresponding first central angles are θ l1 、θ l2 、θ l3, θ l4 The second curve segment A 01 A 02 is formed by the adjacent set of root diameters O1A 02 and top diameters O1A 01 .

[0046] Step S400, determining the second central angle of each first circular arc segment in the first circular arc segment set arranged on the first cross section according to the first central angle corresponding to each third curve segment in the first curve segment set.

[0047] It should be noted that the third curve segment is used to represent each member in the first curve segment set, that is, both the first curve segment and the second curve segment are the third curve segment.

[0048] It should be noted that since the circumferential angle is 360 degrees, the sum of the central angles corresponding to each first circular arc segment in the first circular arc segment set is clear in the case of determining the first central angle, at which time the second central angle can be allocated to each circular arc segment according to the requirement, so as to determine the second central angle. It should be noted that the allocation can be in the form of equal division, or in proportion, and the embodiments of the present application do not make too many constraints here.

[0049] It should be noted that in some embodiments, the first circular arc segment set is composed of the first circular arc segments corresponding to the root diameters and the top diameters, and in other embodiments, transition arcs are interposed between the first curve segments, so that the first circular arc segment set is composed of the transition arcs and the first circular arc segments corresponding to the root diameters and the top diameters.

[0050] Step S500, manufacturing the first screw 210 according to the first curve segment set and the first circular arc segment set.

[0051] It should be noted that in the case of determining the central angle of the third curve segment and each polar diameter, the manufacturing parameters of the third curve segment of the first cross section on the first screw 210 can be determined, and in the case of determining the central angle of the first circular arc segment and the radius, the manufacturing parameters of the first circular arc segment can be determined, so that the first screw 210 can be determined.

[0052] Step S600, determining the second curve segment set corresponding to the first curve segment set and the second circular arc segment set corresponding to the first circular arc segment set on the second screw 220, wherein the ratio of the central angle of each fourth curve segment in the second curve segment set to the corresponding third curve segment is the speed ratio, and the ratio of the central angle of each second circular arc segment in the second circular arc segment set to the corresponding first circular arc segment is the speed ratio.

[0053] It should be noted that the first curve segment set and the second curve segment set are correspondingly arranged to indicate that each corresponding third curve segment and fourth curve segment has a meshing point. In the manufacturing process of the second screw 220, the second line diameter corresponding to the first line diameter is inserted into the second interlaced area corresponding to the first interlaced area, and the sum of the first line diameter and the corresponding second line diameter is the center distance between the first screw 210 and the second screw 220, that is, the sum of the ith largest second line diameter and the ith smallest first line diameter is the center distance. For example, assuming that the first line diameter R lk Satisfies r < R l1 <... < R lk <R, the corresponding second line diameter R rk is as follows, respectively, and satisfies R < R rk <... < R r1 <r, where R r1 and R lk The sum of the maximum polar radius of the fourth curve segment and the minimum polar radius of the corresponding third curve segment is the center distance. At this time, since the first screw 210 and the second screw 220 move in the same direction at different speeds, along the rotational speed direction, as the polar radius of the curve segment of one screw increases, the polar radius of the corresponding curve segment of the other screw decreases, so that the two screws have meshing points at different positions. Therefore, by correspondingly arranging the first screw 210 and the second screw 220 as described above, the meshing track of the first screw 210 and the second screw 220 is more complex.

[0054] Step S700, manufacturing the second screw 220 according to the second curve segment set and the second circular arc segment set.

[0055] Therefore, by arranging the plurality of first curve segments between a set of adjacent root and crest diameters of the first screw 210 and arranging the second curve segments between another set of adjacent root and crest diameters, the first screw 210 is asymmetric and the cross-sectional area of the first screw 210 is increased, so that a wedge-shaped space is formed between the first screw 210 and the inner side wall of the accommodating cavity accommodating the first screw 210 and the wedge-shaped space has a downward or upward trend with the rotation of the first screw 210, and by determining the first curve segment set through the central angle calculation formula and the first curve segment calculation formula and arranging the second curve segment set and the second arc segment set corresponding to the first curve segment set and the first arc segment set on the second screw 220, the meshing points of the first screw 210 and the second screw 220 rotating at the same direction and different speeds are more complex, so that the material is subjected to stronger disturbance and mixing effect; therefore, compared with the related art, the double screw of the present application can provide more complex meshing tracks during movement, and because the cross-sectional area of the first screw 210 and the second screw 220 is increased, a wedge-shaped pressurization extrusion stretching action is generated near the thrust surface or the drag surface of the first screw 210 and the second screw 220, so that the converging material in the lower meshing area is further extruded and stretched, and enters the next screw groove, and the wedge-shaped pressurization action can further improve the dispersion and mixing capacity; therefore, the embodiment of the present application can improve the promotion effect of mixing in the axial flow.

[0056] Both of the two screws adopt the form of constant cross-sectional structure, so that the manufacturing process of the screw is relatively simple, and the symmetry between the two screws is avoided. Moreover, the cross-sectional profile of the first screw 210 is completely asymmetric, and the asymmetric effect of the screw can improve the extrusion and stretching mixing effect of the same-direction differential speed double screw molding device.

[0057] It should be noted that the double screw obtained through the above steps S100-S700 is always meshed when rotating in the same direction as shown in FIG. 1. Figure 2 It should be noted that the double screw obtained through the above steps S100-S700 is always meshed when rotating in the same direction as shown in FIG. 1.

[0058] It should be understood that the first curve segment set arranged on the first screw 210 is determined according to the preset central angle calculation formula and the first curve segment calculation formula, and includes:

[0059] The first central angle corresponding to each first curve segment and second curve segment is determined according to the central angle calculation formula;

[0060] The polar diameter of the first curve segment and the second curve segment is determined according to the first curve segment calculation formula;

[0061] The central angle calculation formula includes formula one and formula two as follows:

[0062] Formula one:

[0063] Formula two:

[0064] wherein θ li is a first central angle corresponding to the first curve segment; θ l0 is a second central angle corresponding to the second curve segment; is a speed ratio and M and N are co-prime; C is a center distance; R li , R l(i+1) are a minimum polar radius and a maximum polar radius of the first curve segment corresponding to θ li , respectively, D is 2R, R is a top radius; i is in a range of 1 to K+1, K is a number of first line diameters.

[0065] It should be noted that in some embodiments, the first central angle and the second central angle can be determined based on a polar radius formula and a polar angle formula, wherein the polar radius formula is as follows: the polar angle formula is as follows: R min is a minimum polar radius of the curve segment. At this time, since the minimum polar radius and the maximum polar radius of one curve segment are determined, based on the polar radius formula, cosε max corresponding to the maximum polar radius can be determined; thus, ε max can be solved according to cosε max , and ψ(ε max ) corresponding to ε li (i.e., the first central angle θ l0 or the second central angle θ li to be solved) can be obtained, so as to obtain the above formula one and formula two.

[0066] It can be understood that the first curve segment calculation formula includes formula three and formula four as follows:

[0067] Formula three:

[0068] Formula four:

[0069] wherein ρ li (ε) is a polar radius of the first curve segment corresponding to θ li ; ρ l0 (ε) is a polar radius of the second curve segment.

[0070] It should be noted that ε is an auxiliary positioning angle, which is a variable value.

[0071] It should be noted that in some embodiments, ε1 is determined through the polar angle formula based on the minimum polar radius and the maximum polar radius of the corresponding first curve segment.

[0072] It can be understood that the first set of circular arc segments is composed of the circular arcs corresponding to the root diameter and the top diameter, or the first set of circular arc segments is composed of the transition circular arc and the circular arcs corresponding to the root diameter and the top diameter; according to the first central angle corresponding to each third curve segment of the first set of curve segments, the second central angle of each first circular arc segment of the first set of circular arc segments arranged on the first cross section is determined, including:

[0073] Subtract 2π from each first central angle to obtain an angle sum value, wherein the angle sum value is the sum of the second central angles of each first circular arc segment;

[0074] The angle sum value is evenly distributed according to the number of first circular arc segments to determine each second central angle.

[0075] It should be noted that when the angle sum value is large, a transition circular arc can be inserted between the adjacent two first curve segments, thereby further increasing the complexity of the movement trajectory of the meshing point. The transition circular arc can be arranged between each adjacent two first curve segments.

[0076] It can be understood that the second set of curve segments corresponding to the first set of curve segments is determined on the second screw 220, including:

[0077] According to the preset second curve segment calculation formula, the speed ratio and each first central angle, a fourth curve segment corresponding to each third curve segment is determined to obtain the second set of curve segments;

[0078] Wherein, the relationship between the third central angle of the fourth curve segment and the first central angle of the third curve segment is as follows:

[0079] Formula five:

[0080] Wherein, θ ri represents the third central angle, θ li represents θ ri corresponding first central angle;

[0081] Wherein, the second curve segment calculation formula includes formula six and formula seven, and formula six and formula seven are as follows:

[0082] Formula six:

[0083] Formula seven:

[0084] Wherein, ψ(ε) is the polar angle of θ ri corresponding fourth curve segment; ρ ri (ε) is the polar radius of θ ri corresponding fourth curve segment; R l(i+1) is the maximum polar radius of θ ri corresponding fourth curve segment.

[0085] Exemplarily, referring to FIG. 1, the first screw 210 and the second screw 220 are arranged in a parallel manner, and the first screw 210 and the second screw 220 are arranged in a parallel manner. Figure 4 As shown in FIG. 1, the rotation speed ratio of the first screw 210 and the second screw 220 is 2:1, and the second curve segment A0A1 corresponds to the first curve segment A0A0. 01 A 02 The fourth curve segment B0B1 corresponds to the first curve segment A0A0. 01 B 02 The fourth curve segment B0B1 corresponds to the first curve segment A0A0. 01 B 02 The central angle of the fourth curve segment B0B1 is The fourth curve segment B0B1 corresponds to the first curve segment A0A0, and referring to the above formula 5, the central angle of the fourth curve segment B0B1 is

[0086] It can be understood that the fourth curve segment corresponding to the first curve segment is arranged as a straight line.

[0087] It should be noted that in some embodiments, when the number of the first curve segments is greater than a preset threshold, the connecting line of the end points corresponding to the first curve segments in the second screw 220 approaches a straight line, and therefore, the connecting line of the end points corresponding to the first curve segments in the first screw 210 (i.e., the fourth curve segment corresponding to the first curve segment) in the second screw 220 can be arranged as a polyline, thereby simplifying the production process of the screw, avoiding the constraint of the engineering formula, and thus improving the production efficiency.

[0088] It can be understood that the number of the first curve segments ranges from 2 to 8.

[0089] It can be understood that the ratio of the number of screw heads of the first screw 210 and the second screw 220 is inversely proportional to the rotation speed ratio.

[0090] It should be noted that by setting the ratio of the number of screw heads as the inverse ratio of the rotation speed ratio, the stability of the double screw during operation can be increased.

[0091] Exemplarily, referring to FIG. 1, the first screw 210 and the second screw 220 are arranged in a parallel manner, and the first screw 210 and the second screw 220 are arranged in a parallel manner. Figures 1 to 3 Assuming that the rotation speed ratio of the first screw 210 and the second screw 220 is M:N. The following is a general cross-sectional structure with M:N as the rotation speed ratio.

[0092] For the first screw 210, K transition radii R li are arranged between the root radius r and the top radius R l1 of the first screw 210, such that r lk <R, i = 1,..., K; and K + 1 first curve segments will be generated, and K transition arcs corresponding to the K transition radii are added, and the central angle of the transition arc is represented by δ i , and the K transition arcs and the K + 1 first curve segments are connected alternately, as shown in FIG. 1 (O1A Figure 3 , O1A 01 , and O1A 00 is the top radius, and O1A02 O1A0 is the root diameter.

[0093] Reference Figure 3 As shown, for the second curved segment A of the first screw 210 01 A 02 The non-circular curve arc between the root diameter r and the tip diameter R of the connecting screw is represented by a circle centered at O1, O1A 02 Let be the polar axis, with counterclockwise direction as positive. Given an auxiliary angle ε, then:

[0094] The corresponding polar radius is:

[0095] The corresponding polar angle is:

[0096] At this point, the second curve segment A 01 A 02 The corresponding central angle is:

[0097] Furthermore, for any one of the first curve segments A in the first screw 210 i A i+1 With O1 as the center, O1A i The polar axis is defined; clockwise is positive, and an auxiliary angle is given. Then we have:

[0098] First curve segment A i A i+1 Corresponding polar diameter

[0099] Corresponding polar angle

[0100] First curve segment A i A i+1 corresponding central angle

[0101] in,

[0102] Here, R li R l(i+1) These represent the first curved segment A of the first screw 210. i A i+1 The corresponding minimum and maximum polar diameters.

[0103] Based on the selected polar diameter R li We can calculate the sum of the central angles corresponding to the K+1 first curve segments formed by the K extreme radii, and finally determine the vertex angle α and base angle λ of the first screw 210 and the central angle δ corresponding to each transition arc. i The sum satisfies the following formula: At this point, the angle and value can be determined using this formula. And according to the preset allocation rules, the angle and value are allocated.

[0104] At this time, refer to Figure 3 As shown, for the second screw 220, K transition polarities R are set between the root diameter r and the screw tip diameter R of the second screw 220. ri , such that r(R) r0 ) <R r1 <R r2 … <R ri <…R rK <R(R r(K+1) Then, (K+1) fourth curve segments B will be generated, each corresponding to one of the first curve segments. i B i+1 , i = 1, ..., K, at this time, the first curve segment and the corresponding fourth curve segment mesh with each other.

[0105] For any segment of curve B of the second screw 220 i B i+1 With O2 as the center, O2B i+1 Let be the polar axis, with counterclockwise direction as positive. Given an auxiliary angle ε, then:

[0106] B i B i+1 The corresponding polar radius is: Among them, R l(i+1) B i B i+1 The maximum polar diameter.

[0107] The second screw 220 B i B i+1 The corresponding polar angle θ ri for: Where, θ li To be with B i B i+1 The first central angle of the corresponding first screw 210.

[0108] Here, the auxiliary angle is ε, and the corresponding polar angle is denoted as ψ(ε), which is related to the speed ratio. The functions for the variation of center distance C and transition polar radius are as follows:

[0109] Similarly, for the fourth curve segment corresponding to the second curve segment, by substituting R as the maximum diameter and r as the minimum diameter into the above formulas for the polar diameter and polar angle, we can obtain the polar diameter and central angle corresponding to the fourth curve segment.

[0110] For example, refer to Figure 4As shown, the first screw 210 and the second screw 220 have a speed ratio of 2:1, a corresponding head ratio of 1:2, three transition diameters, i.e. K=3, and three transition arcs and four non-circular curve segments are added.

[0111] For the second curve segment A 01 A 02 of the first screw 210, the non-circular curve segment connecting the root diameter r and the top diameter R is represented by a circle with O1 as the center, O1A 02 as the polar axis, and the counterclockwise direction as positive. Given an auxiliary angle ε, the following equation is obtained:

[0112] The corresponding polar diameter is:

[0113] The corresponding polar angle is:

[0114] At this time, the non-circular curve segment A 01 A 02 of the first screw 210 has a corresponding central angle θ l0 :

[0115] Further, for any non-circular curve segment A i A i+1 of the first screw 210, a circle with O1 as the center and O1A i as the polar axis is drawn, the clockwise direction is positive, and an auxiliary angle is given. Then the following equation is obtained:

[0116] A i A i+1 The corresponding polar diameter is:

[0117] The corresponding polar angle is:

[0118] The non-circular curve segment A i A i+1 of the first screw 210 has a corresponding central angle θ li :

[0119] wherein,

[0120] Here, R li and R l(i+1) represent the minimum and maximum polar diameters, respectively, of the curve segment A i A i+1 of the first screw 210.

[0121] According to the selected polar diameter R liThe sum of the central angles corresponding to the K+1 curve arcs formed by the K extreme diameters can be calculated. Finally, the vertex angle α and bottom angle γ of the first screw 210 and the central angle δ corresponding to each transition extreme diameter can be determined. i The sum satisfies the following formula:

[0122] Furthermore, for the second screw 220, three transition diameters R are also provided between the screw root diameter r and the screw tip diameter R. ri , such that r(R) r0 ) <R r1 <R r2 … <R ri <R ri+1 <…R rK <R(R r(K+1) If this is done, then (K+1) curves B will be generated. i+1 B i , i = 1, ..., K, at this time, the first screw 210 corresponds to curve arc A i A i+1 Curve B corresponding to the second screw 220 i+1 B i They mesh and operate together.

[0123] For the fourth curve segment B of the second screw 220 01 B 02 With O2 as the center, O2B 01 Let be the polar axis, with clockwise direction as positive. Given an auxiliary angle ε, then:

[0124] For any segment B of the fourth curve of the second screw 220 i+1 B i With O2 as the center, O2B i+1 Let be the polar axis, with counterclockwise direction as positive. Given an auxiliary angle ε, then we have:

[0125] B i+1 B i The corresponding polar radius is: Among them, R l(i+1) B i B i+1 The maximum polar diameter.

[0126] The second screw 220 B i+1 B i The corresponding polar angle θ ri for: Where, θ li To be with B i B i+1 The first central angle of the corresponding first screw 210.

[0127] Here, the auxiliary angle is ε, and the corresponding polar angle is denoted as ψ(ε), which is related to the speed ratio. Center distance C and transition radius R li The function of change:

[0128] It should be noted that, under the premise of ensuring the normal use of the first screw 210 and the second screw 220, the more non-circular arcs on the screw groove surface of the conical twin screw device, the stronger the axial extrusion capacity due to the wedge-shaped pressurization and the cone angle.

[0129] For example, refer to Figure 5 As shown, the speed ratio of the first screw 210 to the second screw 220 is 2:1, corresponding to a head ratio of 1:2. Six transition polarities are set, i.e., K=6. Seven non-circular arc curves are added for the non-circular arc A of the first screw 210. 01 A 02 That is, the non-circular curve arc connecting the root diameter r and the tip diameter R of the connecting screw is represented by a circle with O1 as the center, O1A 02 Let be the polar axis, with counterclockwise direction as positive. Given an auxiliary angle ε, then:

[0130] The corresponding polar radius is:

[0131] The corresponding polar angle is:

[0132] At this point, the non-circular curve arc A 01 A 02 The corresponding central angle is:

[0133] Furthermore, for any non-circular curve arc A of the first screw 210 i A i+1 With O1 as the center, O1A i The polar axis is defined, with clockwise as positive, and an auxiliary angle is given. Then we have:

[0134] First curve segment A i A i+1 Corresponding polar diameter

[0135] Corresponding polar angle

[0136] Non-circular curve arc A i A i+1 The corresponding central angle θ li for:

[0137] in

[0138] Here, Rli , R l(i+1) represent the first curve segment A of the first screw 210 respectively i A i+1 corresponding minimum and maximum polar radius.

[0139] According to the selected polar radius R li , the sum of the central angles corresponding to the K polar radius groups K+1 curve arcs can be calculated, and finally the top angle α and the bottom angle λ of the first screw 210 and the central angle δ of each transition arc are determined i The sum satisfies the following formula: At this time, according to the formula, the angle sum value is And according to the preset distribution rule, the angle distribution is carried out on the angle sum value.

[0140] Further, referring to Figure 5 , for the second screw 220, between the screw root diameter r and the screw top diameter R, 6 transition polar radii R r() are also set r0 , so that r(R r1 )<R r2 …<R ri <…R rK <R(R r(K+1) ), then 14 third curve segments B i B i+1 , i=1,...,K will also be generated, but the curve arc of the double-headed thread structure second screw 220 approximates a straight line, in order to simplify the production process of the screw and eliminate the constraints of the engineering formula, the third curve segments of the second screw 220 except the arc lines of the bottom angle and the top angle and the wrap angle are all replaced by straight lines. At this time, the corresponding curve arc of the first screw 210 is the corresponding straight line B i B i+1 of the second screw 220, i=1,...,K, which are mutually engaged and operated.

[0141] For the non-circular curve arc B 01 B 02 of the second screw 220, with O2 as the center, O2B 01 as the polar axis, the clockwise direction as positive, and the given auxiliary angle ε, then

[0142] For any curve B i+1 B i of the second screw 220, with O2 as the center, O2B i+1 as the polar axis, the counterclockwise direction as positive, and the given auxiliary angle ε, then

[0143] The corresponding polar radius of the curve arc B i+1 B i is:

[0144] Curve B of the second screw 220 i+1 B i The corresponding polar angle θ ri for: Where, θ li To be with B i B i+1 The first central angle of the corresponding first screw 210.

[0145] Here, the auxiliary angle is ε, and the corresponding polar angle is denoted as ψ(ε), which is related to the speed ratio. Center distance C and transition radius R li The function of change:

[0146] Understandably, referring to Figure 2 As shown, Figure 2 The twin screw is manufactured according to the above-described twin screw manufacturing method in an embodiment of this application.

[0147] It should be noted that, with a center distance of 30 mm and a diameter D of 35 mm, the internal volumes of a conventional constant-speed twin-screw, a differential-speed twin-screw, a twin-screw made using this application (Example 1, where the first endpoint connection line includes the third arc segment and the first curved segment), and a twin-screw (Example 2, where the first endpoint connection line only includes the first curved segment) are compared. Figure 6 As shown, the internal volume of the twin-screw extruder manufactured in this application is smaller, thereby improving the mixing effect by reducing the internal volume.

[0148] It should be noted that by adding multiple first wire diameters between the root diameter and the tip diameter of the first screw 210, and adding multiple second wire diameters to the multiple second screws 220, the trajectory of the increased meshing points of the twin screws over time becomes more complex, thus breaking the symmetry. Figure 4 Taking the twin-screw as an example, its motion trajectory is as follows: Figure 8 As shown, Figure 4 The first arc segment A corresponding to the tip diameter of the first screw 210 00 A 01 The first arc segment B corresponding to the root diameter of the second screw 220 00 B 01 The corresponding meshing point of the segment is at Figure 8 A in 701 The root diameter of the first screw 210 corresponds to the first arc segment A0A. 02 The first arc segment B corresponding to the root diameter of the second screw 220 02 The engagement point corresponding to B0 is at A. 020 The engagement points of the other first arc segments of the first screw 210 and the corresponding second screw 220 at the center distance are respectively A 12 A 34 A56 Using the center distance O1O2 between the first screw 210 and the second screw 220 as the dividing line, it can be seen that the upper part of O1O2 is the upper meshing zone, and the lower part of O1O2 is the lower meshing zone. The melting section 120 mainly occurs in the lower meshing zone, and the movement trajectory of the meshing point in the lower meshing zone exhibits a "half-wave" disturbance state, compared to... Figure 9 The shown is the meshing point motion trajectory of a traditional constant-speed twin-screw extruder. Figure 9 The center distance between the two screws is used as the dividing line. The movement trajectory of the meshing point is symmetrical in all directions and there is only one wave disturbance effect. Therefore, the material cannot be fully squeezed, stretched and disturbed. The twin screw of this application embodiment can increase more meshing points, thereby increasing the meshing area. Due to the complex movement trajectory of the meshing points, the material is subjected to stronger disturbance and mixing effect in this meshing area.

[0149] For example, refer to Figure 4 and Figure 5 For example, according to the manufacturing method of the twin-screw described above in this application, a first curved segment with a transition arc inserted in the middle can be manufactured, such as... Figure 4 The first screw 210 shown can also be used to create a first curved segment without a transition arc, such as... Figure 5 The first screw 210 is shown. The first screw 210 and the second screw 220, manufactured according to embodiments of this application, are tapered, so as to... Figure 4 Taking the first screw 210 as an example, refer to Figure 10 As shown, the angle between the inner wall surface of the barrel 100 and the nearly straight surface on the screw is a cone angle β1, where A′ 00 A′ 01 A′ 02 A′ 03 A′1, A′2, A′3, A′4, A′5, and A′6 correspond to respectively Figure 4 A7 and A7 of the cross-sectional structural diagram 01 A 02 A0, A1, A2, A3, A4, A5, and A6; Figure 5 Taking the first screw 210 as an example, refer to Figure 11 As shown, the angle between the inner wall surface of the barrel 100 and the nearly straight surface on the screw is a cone angle β2, where A′ 00 A′ 01 A′ 02 A′ 03 A′1, A′2, A′3, A′4, A′5, and A′6 correspond to respectively Figure 5 A7 and A7 of the cross-sectional structural diagram 01 A 02 A0, A1, A2, A3, A4, A5 and A6.

[0150] It can be understood that the extruder according to the embodiment of the present application comprises:

[0151] A barrel 100, an inner cavity of the barrel 100 is provided as two intersecting cylindrical grooves;

[0152] Double screws, the double screws are made by the method for making the double screws as described above, a first screw 210 of the double screws is located in one of the cylindrical grooves, and a second screw 220 of the double screws is located in the other cylindrical groove.

[0153] For the extruder, referring to Figure 12 The use process is as follows:

[0154] After the material enters the barrel 100 from the feeding port 111, the first screw 210 and the second screw 220 rotate at the same direction and at different speeds; after the material enters the solid conveying section 110, the material is forced to move towards the discharging port 141 under the conveying effect of the positive displacement and frictional dragging of the differential rotation of the first screw 210 and the second screw 220.

[0155] When the material is conveyed to the melting section 120, the first screw 210 and the second screw 220 rotate at different speeds along their respective axes to periodically compress and expand the conveying space to convey the material; during the rotation of the first screw 210 and the second screw 220, the two screws are always engaged with each other, the engagement effect of the upper and lower engagement zones and the extrusion stretching effect of the material away from the engagement zone caused by the wedge-shaped gap cause the material to be extruded and work, and the high-speed rotation of the first screw 210 and the second screw 220 also generates frictional heat, which, together with the heating outside the barrel 100, further melts and mixes the material, and the mutual wiping effect of the first screw 210 and the second screw 220 accelerates the melting and mixing process of the material, so that the material becomes a melt;

[0156] After the melt enters the degassing section 130, the rotation of the first screw 210 and the second screw 220 continuously overturns and forcibly peels off the material adhered to the screws, the rotation speed of the first screw 210 and the second screw 220 causes the force field in the flow channel 300 to be unbalanced, which generates a stretching force field and an extrusion effect on the material and an axial mixing effect, accelerates the discharge of gas from the degassing port 131, and the melt further moves towards the discharging port 141;

[0157] After the melt enters the mixing and extruding section 140, the melt moves forward under the periodic compression and expansion of the space caused by the rotation of the first screw 210 and the second screw 220, the engagement effect of the upper and lower engagement zones and the extrusion stretching effect of the material away from the engagement zone caused by the wedge-shaped gap further strengthen the mixing and plasticizing of the material, and the mutual wiping effect between the first screw 210 and the second screw 220 realizes the self-cleaning effect and the extrusion stretching effect, so that the melt is stably extruded from the discharging port 141.

[0158] The preferred embodiments of the present application are described above with reference to the accompanying drawings, and are not intended to limit the scope of the present application. Any modification, equivalent replacement and improvement made by those skilled in the art without departing from the scope and spirit of the present application shall fall within the scope of the present application.

Claims

1. A method of manufacturing a twin screw, characterized by, The manufacturing method comprises: determining the root diameter, the top diameter, the rotational speed ratio of the first screw and the second screw, and the center distance between the first screw and the second screw; determining the first linear diameter and the number of the first linear diameters which are arranged in a first intercalation area formed by a group of adjacent root diameters and top diameters on a first cross section of the first screw according to the center distance; determining a first curve segment set arranged on the first screw according to a preset central angle calculation formula and a first curve segment calculation formula, wherein the first curve segment set is composed of a plurality of first curve segments obtained by intercalating the first linear diameters in the first intercalation area and a second curve segment formed by another group of adjacent root diameters and top diameters; determining a second central angle of each first arc segment of a first arc segment set arranged on the first cross section according to a corresponding first central angle of each third curve segment of the first curve segment set; manufacturing the first screw according to the first curve segment set and the first arc segment set; determining a second curve segment set corresponding to the first curve segment set and a second arc segment set corresponding to the first arc segment set on the second screw, wherein a ratio of a central angle of each fourth curve segment in the second curve segment set to a corresponding third curve segment is the rotational speed ratio, and a ratio of a central angle of each second arc segment in the second arc segment set to a corresponding first arc segment is the rotational speed ratio; manufacturing the second screw according to the second curve segment set and the second arc segment set.

2. A method of manufacturing a twin screw according to claim 1, wherein The determining of the first curve segment set arranged on the first screw according to the preset central angle calculation formula and the first curve segment calculation formula comprises: determining a first central angle corresponding to each first curve segment and second curve segment respectively according to the central angle calculation formula; determining a polar diameter of the first curve segment and the second curve segment respectively according to the first curve segment calculation formula; wherein the central angle calculation formula comprises formula one and formula two as follows: Formula One: , ; Formula II: ; wherein, is a first central angle corresponding to the first curve segment; is a first central angle corresponding to the second curve segment; is the speed ratio and and irreducible; is the center distance; , are respectively the minimum and maximum polar radii of the corresponding first curve segment, is , is the top diameter; the value range of K is 1~K+1, and K is the number of the first line diameters.

3. A method of manufacturing a twin screw according to claim 2, wherein the first curve segment calculation formula comprises formula three and formula four as follows: Formula Three: ; Formula Four: ; wherein is the polar radius of the corresponding first curve segment; is the polar radius of the second curve segment.

4. The method of claim 2, wherein the step of forming the twin screw comprises the step of: the first arc segment set is composed of arcs corresponding to the root diameter and the top diameter, or the first arc segment set is composed of a transition arc and arcs corresponding to the root diameter and the top diameter; the determining of a second central angle of each first arc segment of a first arc segment set arranged on the first cross section according to a corresponding first central angle of each third curve segment of the first curve segment set comprises: subtracting each first central angle from 2π to obtain an angle sum, wherein the angle sum is a sum of the second central angles of each first arc segment; distributing the angle sum to each first arc segment according to the number of the first arc segments to determine each second central angle.

5. The method of claim 2, wherein the step of forming the twin screw comprises the step of: The determining of a second curve segment set corresponding to the first curve segment set on the second screw comprises: determining a fourth curve segment corresponding to each third curve segment one by one to obtain the second curve segment set according to a preset second curve segment calculation formula, the rotational speed ratio, and each first central angle; wherein a relationship between a third central angle of the fourth curve segment and the first central angle of the third curve segment is as follows: Formula Five: ; wherein denotes a third central angle, denotes a corresponding first central angle; wherein the second curve segment calculation formula comprises formula six and formula seven as follows: Formula Six: ; Formula Seven: ; wherein is the polar angle of the corresponding fourth curve segment; is the polar radius of the corresponding fourth curve segment; is the maximum polar radius of the corresponding fourth curve segment; is the auxiliary angle, said is the inverse of the speed ratio.

6. The method for manufacturing a twin-screw extruder according to claim 1, characterized in that, The fourth curve segment corresponding to the first curve segment is a straight line.

7. The method of claim 1, wherein the twin screw is made of a material selected from the group consisting of: aluminum, steel, and stainless steel. The number of the first curve segments ranges from 2 to 8.

8. The method of claim 1, wherein the twin screw is made of a material selected from the group consisting of: aluminum, steel, and stainless steel. The ratio of the number of screw heads of the first screw and the second screw is inversely proportional to the ratio of the rotational speeds.

9. A twin screw characterized in that, The double screw is made by the method as claimed in any one of claims 1 to 8.

10. An extruder characterized by, Comprising: A barrel, an inner cavity of the barrel being provided as two intersecting cylindrical grooves; A double screw made by the method as claimed in any one of claims 1 to 8, a first screw of the double screw being located in one of the cylindrical grooves, and a second screw of the double screw being located in the other cylindrical groove.

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