A multi-layer flat taper die

Abstract

The utility model discloses a multilayer plane taper die head, including die holder, upper die plate, lower die plate, die core, die nozzle and a plurality of middle die plate, the lower end surface of upper die plate, the lower end surface of each middle die plate all is equipped with the convex round table of big from big to small, is equipped with a plurality of spiral grooves that are evenly distributed along the circumference of convex round table on the outer wall of convex round table, be equipped with the recessed cavity in each middle die plate, lower die plate, each convex round table is in the corresponding recessed cavity respectively, each convex round table is equipped with circular cavity, and circular cavity is below recessed cavity, and each circular cavity is sequentially communicated from top to bottom and forms die cavity, and die core is in die cavity, and forms extrusion runner between die core and die cavity, each spiral groove and recessed cavity inner wall form a plurality of spiral runner, between upper die plate and the uppermost middle die plate, between each adjacent middle die plate, between the lowermost middle die plate and lower die plate all are equipped with multistage plane runner, and the upper end of each spiral runner is connected with the corresponding end of multistage plane runner respectively.

Description

Technical Field

[0001] This utility model relates to the field of blown film equipment technology, and in particular to a multi-layer planar tapered die head. Background Technology

[0002] Currently, co-extrusion blow molding units are commonly used to manufacture multilayer films. During manufacturing, multiple extruders process and extrude the raw materials for each layer separately, then blow them through a blown film tower to form a film tube. For example, the invention patent CN117021552B discloses an energy-saving "POF multilayer" blown film machine, including an extrusion die, a conveying mechanism, a winding mechanism, and multiple extrusion main units. Along the conveying direction of the conveying mechanism, the extrusion main units, extrusion die, and winding mechanism are arranged sequentially. The extrusion die includes a die cylinder, a die core, a flow channel body, and a die nozzle. The flow channel body is located in the die cylinder, the die core is located in the flow channel body, and the die nozzle is located at the lower end of the die core and within the flow channel body. An extrusion flow channel is formed between the die core and the flow channel body, and the extrusion flow channel is connected to the extrusion port of the die nozzle. The flow channel body includes multiple annular flow channel sub-layers arranged sequentially from top to bottom. Each extrusion die layer has a horizontally arranged main channel and multiple branch channels. The main channel has a feed inlet and multiple branch outlets. Along the conveying direction of the main channel, the distance between adjacent branch outlets is equal. The number of branch outlets is the same as the number of branch channels, and they correspond one-to-one. The feed inlet of each branch channel is connected to the corresponding branch outlet. Each branch channel is arc-shaped and has the same length. The number of annular flow channel layers is the same as the number of extrusion main units, and they correspond one-to-one. The feed inlet of the main channel in the annular flow channel layer is connected to the discharge end of the corresponding extrusion main unit. The ends of each branch channel are located on the inner side of the annular flow channel layer and are connected to the extrusion flow channel. The flow channel structure of the above extrusion die head only adopts a single-stage flow distribution (main channel → branch channel), without a multi-stage pressure stabilization flow distribution design. The circumferential pressure and flow rate deviation of the melt are large, and the thickness uniformity of the extruded multilayer film is extremely poor, easily resulting in thick and thin edges. Moreover, each flow channel is a horizontal annular structure, without flow guidance in the vertical direction of the extrusion channel. The melt flow is prone to eddies, stagnation, and stratification. The bonding force of multi-layer melt is weak, and the film is prone to delamination and cracking. Utility Model Content

[0003] The problem this invention aims to solve is to provide a multi-layer planar tapered die. This multi-layer planar tapered die can achieve multi-stage pressure stabilization and flow distribution, extend plasticizing time, and improve the uniformity of extruded multi-layer film thickness and the bonding force of multi-layer melts.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0005] A multi-layer planar tapered die head includes a die base, an upper die plate, a lower die plate, a die core, a die nozzle, and multiple intermediate die plates. The die nozzle, lower die plate, each intermediate die plate, upper die plate, and die base are stacked and connected sequentially from bottom to top. The upper die plate and each intermediate die plate have a convex truncated cone with a larger upper diameter and a smaller lower diameter on their lower end faces. Multiple spiral grooves evenly distributed along the circumference of the convex truncated cone are provided on the outer wall of the convex truncated cone. Each lower die plate and each intermediate die plate has a cavity with an inner diameter that gradually decreases from top to bottom, and each convex truncated cone is located in a corresponding cavity. Each convex truncated cone has a circular cavity communicating with the cavity, and the circular cavity is located below the cavity. The circular cavities are arranged from top to bottom... The mold core is located in the mold cavity, and an extrusion channel is formed between the outer wall of the mold core and the inner wall of the mold cavity. The spiral grooves on the outer wall of the convex cylinder and the inner wall of the corresponding cavity form multiple spiral channels. Multiple planar channels are provided between the upper mold plate and the uppermost middle mold plate, between each adjacent middle mold plate, and between the lowermost middle mold plate and the lower mold plate. The upper mold plate and each middle mold plate are provided with feeding channels. The discharge end of each feeding channel is connected to the beginning end of the corresponding multi-level planar channel. The upper end of each spiral channel is connected to the corresponding end of the multi-level planar channel. The lower end of each spiral channel is connected to the feed port of the mold nozzle through the extrusion channel.

[0006] During assembly, the convex frustum of the bottom middle template is placed in the cavity of the lower template. Then, the convex frustums of each middle template are placed in the cavities of the adjacent middle templates below. Finally, the convex frustum of the upper template is placed in the cavity of the top middle template. This creates multiple spiral flow channels between the spiral grooves on the outer wall of each convex frustum and the inner wall of the corresponding cavity. The circular cavities of each convex frustum are connected from top to bottom to form a mold cavity. The mold core is then placed in the mold cavity, creating an extrusion flow channel between the outer wall of the mold core and the inner wall of the mold cavity. The lower ends of each spiral flow channel are connected to the feed port of the die nozzle through the extrusion flow channel.

[0007] During operation, the plastic melt is first fed into the corresponding multi-stage planar flow channel from each feed channel, and then flows into the spiral flow channel along the multi-stage planar flow channel; then, the plastic melt flows spirally from top to bottom along the spiral flow channel, and then merges into the extrusion channel, and finally is extruded from the extrusion port of the die to form a multi-layer film tube.

[0008] The upper template and each of the intermediate templates stacked from top to bottom are independent layered flow channel units. The feeding channels of the upper template and each intermediate template can be connected to an independent extruder. Different extruders can feed plastic melts of different materials, different formulations and different colors into the flow channel system of the corresponding intermediate template. After independent diversion and spiral guidance, each layer of plastic melt is bonded and co-extruded from top to bottom in the extrusion channel, and finally extruded synchronously from the die nozzle to form a multi-layer integrated composite film tube with tight interlayer bonding, no delamination and no bubbles.

[0009] In a preferred embodiment, the multi-stage planar flow channel includes a main flow channel, two primary branch flow channels, and four secondary branch flow channels. The main flow channel has two primary branch flow ports, each primary branch flow channel has two secondary branch flow ports, and each secondary branch flow channel has two tertiary branch flow ports. The number of tertiary branch flow ports is the same as that of the spiral flow channels and they correspond one-to-one. The feed channel is connected to the feed port of the main flow channel, the feed port of the primary branch flow channel is connected to the corresponding primary branch flow port, the feed port of the secondary branch flow channel is connected to the corresponding secondary branch flow port, and the upper end of each spiral flow channel is connected to the corresponding tertiary branch flow port. During operation, the molten plastic is fed into the corresponding main channel from each feed channel. The molten plastic flows along the main channel and flows into the primary branch channel when it reaches each primary branch port. It then flows along the primary branch channel and flows into the secondary branch channel when it reaches each secondary branch port. It then flows along the secondary branch channel and flows into the spiral channel when it reaches each tertiary branch port. It then flows spirally from top to bottom along the spiral channel and then merges into the extrusion channel. Finally, it is extruded from the die nozzle to form a multi-layered thin film tube.

[0010] In a further preferred embodiment, the lower surface of the upper template and the lower surface of each of the intermediate templates are provided with a first strip-shaped groove, a second strip-shaped groove, and a third strip-shaped groove from the outside to the inside, with the openings of the first, second, and third strip-shaped grooves all facing downwards; the upper surface of each of the intermediate templates is provided with a fourth, fifth, and sixth strip-shaped groove from the outside to the inside, with the openings of the fourth, fifth, and sixth strip-shaped grooves all facing upwards; the opening of the fourth strip-shaped groove has the same shape and size as the opening of the first strip-shaped groove and forms the main flow channel vertically; the opening of the fifth strip-shaped groove has the same shape and size as the opening of the second strip-shaped groove and forms the primary flow channel vertically; the opening of the sixth strip-shaped groove has the same shape and size as the opening of the third strip-shaped groove and forms the secondary flow channel vertically.

[0011] In a further preferred embodiment, the cross-sectional shapes of the first, second, third, fourth, fifth, and sixth strip grooves are all semi-circular, triangular, or rectangular.

[0012] In a further preferred embodiment, the width of the main flow channel is greater than the width of the primary branch channel, and the width of the primary branch channel is greater than the width of the secondary branch channel; the depth of the main flow channel is greater than the depth of the primary branch channel, and the depth of the primary branch channel is greater than the depth of the secondary branch channel. The progressively decreasing width and depth of these flow channels result in a progressively shrinking cross-section, leading to a progressively increasing pressure in the plastic melt, achieving stable pressure increase, and preventing melt backflow and eddies. The progressively changing diameter adapts to the flow characteristics of the plastic melt, resulting in clearer layering and flow division, preventing melt mixing in different branch sections, and ensuring clear boundaries between multilayer film layers.

[0013] In a further preferred embodiment, the main flow channel is arc-shaped and located on the outer side of each of the corresponding primary distribution channels, while each primary distribution port is located on the inner side of the main flow channel. This arc-shaped main flow channel ensures smooth flow of the molten plastic without dead zones, preventing stagnation and degradation. The external placement of the main flow channel and the internal placement of the distribution ports shorten the distribution path, allowing the molten plastic to enter the primary distribution channels quickly and evenly, resulting in a more balanced circumferential pressure distribution.

[0014] In a further preferred embodiment, along the conveying direction of the main channel, the distances between the two primary diversion ports and the discharge ends of the feed channel are equal. Each primary diversion channel is arc-shaped and of equal length. Because the distances between the two primary diversion ports and the discharge ends of the feed channel are equal, and the lengths of each primary diversion channel are equal, the distances between the discharge points of the primary diversion channels extending from adjacent primary diversion ports are also equal. Therefore, when the plastic melt is extruded from each discharge end, the diversion pressure is uniform, and the temperature is equal. This results in each film layer having the same thickness after extrusion, and the thickness of each film layer is equal at all locations, maintaining good consistency among the film layers. This eliminates the need for a dedicated device to detect and control the extrusion pressure, effectively reducing equipment and manufacturing costs.

[0015] In a further preferred embodiment, along the conveying direction of the primary distribution channel, the distances between the two secondary distribution ports and their corresponding primary distribution ports are equal. Each secondary distribution channel is arc-shaped and of equal length. Similarly, along the conveying direction of the secondary distribution channels, the distances between the two tertiary distribution ports and their corresponding secondary distribution ports are equal. Because the distances between the two secondary distribution ports and their corresponding primary distribution ports are equal, and the lengths of each secondary distribution channel are equal, the distances between the discharge points of the secondary distribution channels extending from adjacent secondary distribution ports are also equal. Therefore, when the plastic melt is extruded from each discharge end, the distribution pressure is uniform, and the temperature is equal, resulting in uniform thickness of each film layer after extrusion. Furthermore, the thickness of each film layer is equal at all locations, further ensuring good consistency among the film layers.

[0016] In the preferred embodiment, the depth and width of the spiral groove gradually decrease from top to bottom. This design causes the spiral flow channel to gradually contract from top to bottom, continuously increasing the flow pressure of the plastic melt and resulting in a significant pressure boosting and flow stabilization effect. The gradient groove shape allows the melt to fit tightly along the tapered cavity, resulting in smoother flow without stagnation or air bubbles.

[0017] Compared with the prior art, this utility model has the following advantages:

[0018] (1) This utility model adopts multi-level planar flow channel and spiral flow channel for circumferential uniform spiral flow guidance, and the melt pressure, flow rate and temperature are consistent. It can stabilize the pressure and divide the flow in multiple stages, extend the plasticizing time, and improve the uniformity of the thickness of the extruded multi-layer film and the bonding force of the multi-layer melt.

[0019] (2) This utility model forms a gradually shrinking flow channel with a larger upper part and a smaller lower part by using a convex truncated cone and a tapered concave cavity. The spiral flow channel synchronously increases and stabilizes the pressure, eliminates eddies and stagnation, and keeps the melt extrusion speed constant, thereby improving the forming accuracy of the film tube.

[0020] (3) This utility model uses multiple intermediate templates with independent feeding channels stacked independently, which can independently connect plastic melts of different materials and formulations without replacing the overall die head, and is suitable for multi-layer co-extrusion of all categories such as POF, PE, and PP. Attached Figure Description

[0021] Figure 1 This is a structural schematic diagram of a specific embodiment of the present utility model;

[0022] Figure 2 This is a schematic diagram of the structure of a multi-stage planar flow channel according to a specific embodiment of this utility model;

[0023] Figure 3 This is a schematic diagram of the structure of the template in a specific embodiment of this utility model;

[0024] Figure 4 This is a schematic diagram of the spiral groove of the intermediate template in a specific embodiment of this utility model;

[0025] Figure 5 This is a schematic diagram of the structure of the intermediate template in a specific embodiment of this utility model;

[0026] Figure 6 This is a schematic diagram of the template structure in a specific embodiment of this utility model. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1-6As shown, the multi-layer planar tapered die head in this embodiment includes a die base 1, an upper template 2, a lower template 3, a die core 4, a die nozzle 5, and multiple intermediate templates 6. The die nozzle 5, lower template 3, each intermediate template 6, upper template 2, and die base 1 are stacked and connected sequentially from bottom to top. The lower end face of the upper template 2 and the lower end face of each of the intermediate templates 6 are provided with a convex truncated cone 21 that is larger at the top and smaller at the bottom. The outer wall of the convex truncated cone 21 is provided with multiple spiral grooves 22 that are evenly distributed along the circumference of the convex truncated cone 21. The lower template 3 and each intermediate template 6 are provided with a cavity 31 whose inner diameter gradually decreases from top to bottom. Each convex truncated cone 21 is located in a corresponding cavity 31. Each convex truncated cone 21 is provided with a circular cavity 23 that communicates with the cavity 31. The circular cavity 23 is located below the cavity 31. The mold cavity 7 is formed by connecting the mold core 4 from top to bottom. The mold core 4 is located in the mold cavity 7. An extrusion channel 8 is formed between the outer wall of the mold core 4 and the inner wall of the mold cavity 7. The spiral grooves 22 on the outer wall of the convex cylinder 21 and the inner wall of the corresponding cavity 31 form multiple spiral channels 24. Multiple planar channels 9 are provided between the upper template 2 and the uppermost middle template 6, between each adjacent middle template 6, and between the lowermost middle template 6 and the lower template 3. The upper template 2 and each middle template 6 are provided with feeding channels 25. The discharge end of each feeding channel 25 is connected to the beginning end of the corresponding multi-level planar channel 9. The upper end of each spiral channel 24 is connected to the corresponding end of the multi-level planar channel 9. The lower end of each spiral channel 24 is connected to the feed port of the die nozzle 5 through the extrusion channel 8.

[0029] During assembly, the convex frustum 21 of the bottom middle template 6 is placed in the cavity 31 of the lower template 3. Then, the convex frustums 21 of each middle template 6 are placed in the cavity 31 of the adjacent middle template 6 below. Finally, the convex frustum 21 of the upper template 2 is placed in the cavity 31 of the top middle template 6, so that the spiral grooves 22 on the outer wall of each convex frustum 21 and the inner wall of the corresponding cavity 31 form multiple spiral flow channels 24. The circular cavities 23 of each convex frustum 21 are connected from top to bottom to form a mold cavity 7. Then, the mold core 4 is placed in the mold cavity 7, so that the outer wall of the mold core 4 and the inner wall of the mold cavity 7 form an extrusion flow channel 8. The lower end of each spiral flow channel 24 is connected to the feed port of the die nozzle 5 through the extrusion flow channel 8.

[0030] During operation, the plastic melt is first fed from each feed channel 25 into the corresponding multi-stage planar flow channel 9, and flows into the spiral flow channel 24 along the multi-stage planar flow channel 9; then, the plastic melt flows spirally from top to bottom along the spiral flow channel 24, and then merges into the extrusion flow channel 8, and finally is extruded from the extrusion port of the die 5 to form a multi-layer film tube.

[0031] The upper template 2 and each of the intermediate templates 6 stacked from top to bottom are independent layered flow channel units. The feeding channels 25 of the upper template 2 and each intermediate template 6 can be connected to an independent extruder. Different extruders can feed plastic melts of different materials, different formulas and different colors into the flow channel system of the corresponding intermediate template 6. After independent diversion and spiral guidance, each layer of plastic melt is bonded and co-extruded from top to bottom in the extrusion channel 8, and finally extruded synchronously from the die nozzle 5 to form a multi-layer integrated composite film tube with tight interlayer bonding, no delamination and no bubbles.

[0032] The multi-stage planar flow channel 9 includes a main flow channel 91, two primary branch flow channels 92, and four secondary branch flow channels 93. The main flow channel 91 has two primary branch flow ports 911, each primary branch flow channel 92 has two secondary branch flow ports 921, and each secondary branch flow channel 93 has two tertiary branch flow ports 931. The number of tertiary branch flow ports 931 is the same as that of the spiral flow channels 24 and they correspond one-to-one. The feed channel 25 is connected to the feed port of the main flow channel 91, the feed port of the primary branch flow channel 92 is connected to the corresponding primary branch flow port 911, the feed port of the secondary branch flow channel 93 is connected to the corresponding secondary branch flow port 921, and the upper end of each spiral flow channel 24 is connected to the corresponding tertiary branch flow port 931. During operation, the molten plastic is fed from each feed channel 25 into the corresponding main channel 91. The molten plastic flows along the main channel 91 and flows into the primary branch channel 92 when it reaches each primary branch port 911. It then flows along the primary branch channel 92 and flows into the secondary branch channel 93 when it reaches each secondary branch port 921. It then flows along the secondary branch channel 93 and flows into the spiral channel 24 when it reaches each tertiary branch port 931. It then flows spirally from top to bottom along the spiral channel 24 and then merges into the extrusion channel 8, and finally is extruded from the extrusion port of the die 5 to form a multi-layered thin film tube.

[0033] The lower surface of the upper template 2 and the lower surface of each of the intermediate templates 6 are provided with a first strip groove 26, a second strip groove 27, and a third strip groove 28 from the outside to the inside, with the openings of the first strip groove 26, the second strip groove 27, and the third strip groove 28 all facing downwards; the upper surface of each of the intermediate templates 6 is provided with a fourth strip groove 61, a fifth strip groove 62, and a sixth strip groove 63 from the outside to the inside, with the openings of the fourth strip groove 61, the fifth strip groove 62, and the sixth strip groove 63 all facing upwards; the opening of the fourth strip groove 61 is the same shape and size as the opening of the first strip groove 26 and forms the main flow channel 91 vertically; the opening of the fifth strip groove 62 is the same shape and size as the opening of the second strip groove 27 and forms the primary flow channel 92 vertically; the opening of the sixth strip groove 63 is the same shape and size as the opening of the third strip groove 28 and forms the secondary flow channel 93 vertically.

[0034] The width of the main flow channel 91 is greater than the width of the primary branch flow channel 92, and the width of the primary branch flow channel 92 is greater than the width of the secondary branch flow channel 93; the depth of the main flow channel 91 is greater than the depth of the primary branch flow channel 92, and the depth of the primary branch flow channel 92 is greater than the depth of the secondary branch flow channel 93. The progressively decreasing width and depth of these flow channels result in a progressively shrinking cross-section, leading to a progressively increasing pressure in the plastic melt. This achieves stable pressure increase and prevents melt backflow and eddies. The progressively changing diameter adapts to the flow characteristics of the plastic melt, resulting in clearer layering and flow separation, preventing melt mixing in different branch sections, and ensuring clear boundaries between multilayer film layers.

[0035] The cross-sectional shapes of the first groove 26, the second groove 27, the third groove 28, the fourth groove 61, the fifth groove 62, and the sixth groove 63 are all semi-circular, triangular, or rectangular.

[0036] The main channel 91 is arc-shaped and is located on the outer side of each of the corresponding primary distribution channels 92, while each of the primary distribution ports 911 is located on the inner side of the main channel 91. The arc-shaped main channel 91 allows the plastic melt to flow smoothly without dead zones, preventing the plastic melt from stagnating and degrading; the external placement of the main channel 91 and the internal placement of the distribution ports shorten the distribution path, allowing the plastic melt to enter the primary distribution channel 92 quickly and evenly, resulting in a more balanced circumferential pressure distribution.

[0037] Along the conveying direction of the main channel 91, the distances between the two primary diversion ports 911 and the discharge ends of the feed channel 25 are equal. Each primary diversion channel 92 is arc-shaped and of equal length. Because the distances between the two primary diversion ports 911 and the discharge ends of the feed channel 25 are equal, and the lengths of each primary diversion channel 92 are equal, the distances between the discharge points of the primary diversion channels 92 extending from adjacent primary diversion ports 911 are also equal. Therefore, when the plastic melt is extruded from each discharge end, the diversion pressure is uniform, and the temperature is equal, resulting in uniform thickness of each film layer after extrusion. Furthermore, the thickness of each film layer is equal at all locations, ensuring good consistency among the film layers. This eliminates the need for a dedicated device to detect and control the extrusion pressure, effectively reducing equipment and manufacturing costs.

[0038] Along the conveying direction of the primary diversion channel 92, the distances between the two secondary diversion ports 921 and their corresponding primary diversion ports 911 are equal. Each secondary diversion channel 93 is arc-shaped and of equal length. Along the conveying direction of the secondary diversion channel 93, the distances between the two tertiary diversion ports 931 and their corresponding secondary diversion ports 921 are equal. Because the distances between the two secondary diversion ports 921 and their corresponding primary diversion ports 911 are equal, and the lengths of each secondary diversion channel 93 are equal, the distances between the discharge points of the secondary diversion channels 93 extending from adjacent secondary diversion ports 921 are also equal. Therefore, when the plastic melt is extruded from each discharge end, the diversion pressure is uniform, and the temperature is equal, resulting in uniform thickness of each film layer after extrusion. Furthermore, the thickness of each film layer is equal at all locations, further ensuring good consistency among the film layers.

[0039] The depth and width of the spiral groove 22 gradually decrease from top to bottom. This design allows the spiral flow channel 24 to gradually contract from top to bottom, continuously increasing the flow pressure of the plastic melt and resulting in a significant pressure boosting and flow stabilization effect. The gradient groove shape allows the melt to fit tightly along the tapered cavity 31, resulting in smoother flow without stagnation or bubbles.

[0040] Furthermore, it should be noted that the names of the various parts of the specific embodiments described in this specification may differ. All equivalent or simple variations made to the structure, features, and principles described in this utility model patent concept are included within the protection scope of this utility model patent. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the structure of this utility model or exceed the scope defined in these claims, they should all fall within the protection scope of this utility model.

Claims

1. A multi-layer planar tapered die head, comprising a die base, an upper template, a lower template, a die core, a die nozzle, and multiple intermediate templates, wherein the die nozzle, the lower template, each intermediate template, the upper template, and the die base are stacked and connected sequentially from bottom to top; characterized in that: The lower end face of the upper template and the lower end face of each of the intermediate templates are provided with a convex truncated cone that is larger at the top and smaller at the bottom. Multiple spiral grooves evenly distributed along the circumference of the convex truncated cone are provided on its outer wall. Each of the lower template and intermediate templates has a cavity with an inner diameter that gradually decreases from top to bottom, and each convex truncated cone is located in a corresponding cavity. Each convex truncated cone has a circular cavity communicating with the cavity below it. These circular cavities are sequentially connected from top to bottom to form a mold cavity. The mold core is located within the mold cavity, and an extrusion joint is formed between the outer wall of the mold core and the inner wall of the mold cavity. The flow channels are as follows: the spiral grooves on the outer wall of the convex truncated cone and the inner wall of the corresponding cavity form multiple spiral flow channels; multiple planar flow channels are provided between the upper template and the uppermost middle template, between each adjacent middle template, and between the lowermost middle template and the lower template; the upper template and each middle template are provided with feeding channels; the discharge end of each feeding channel is connected to the beginning end of the corresponding multi-level planar flow channel; the upper end of each spiral flow channel is connected to the corresponding end of the multi-level planar flow channel; and the lower end of each spiral flow channel is connected to the feed port of the die through the extrusion channel.

2. The multi-layer planar tapered die head as described in claim 1, characterized in that: The multi-stage planar flow channel includes a main flow channel, two primary branch flow channels, and four secondary branch flow channels. The main flow channel has two primary branch flow ports, each primary branch flow channel has two secondary branch flow ports, and each secondary branch flow channel has two tertiary branch flow ports. The number of tertiary branch flow ports is the same as that of the spiral flow channels and they correspond one-to-one. The feed channel is connected to the feed port of the main flow channel, the feed port of the primary branch flow channel is connected to the corresponding primary branch flow port, the feed port of the secondary branch flow channel is connected to the corresponding secondary branch flow port, and the upper end of each spiral flow channel is connected to the corresponding tertiary branch flow port.

3. The multi-layer planar tapered die head as described in claim 2, characterized in that: The lower surface of the upper template and the lower surface of each of the intermediate templates are provided with a first strip groove, a second strip groove, and a third strip groove from the outside to the inside, with the openings of the first, second, and third strip grooves all facing downwards; the upper surface of each of the intermediate templates is provided with a fourth strip groove, a fifth strip groove, and a sixth strip groove from the outside to the inside, with the openings of the fourth, fifth, and sixth strip grooves all facing upwards; the opening of the fourth strip groove is the same shape and size as the opening of the first strip groove and forms the main flow channel vertically; the opening of the fifth strip groove is the same shape and size as the opening of the second strip groove and forms the primary flow channel vertically; the opening of the sixth strip groove is the same shape and size as the opening of the third strip groove and forms the secondary flow channel vertically.

4. The multi-layer planar tapered die head as described in claim 3, characterized in that: The cross-sectional shapes of the first, second, third, fourth, fifth, and sixth strip grooves are all semi-circular, triangular, or rectangular.

5. The multi-layer planar tapered die head as described in claim 3, characterized in that: The width of the main flow channel is greater than the width of the primary branch flow channel, and the width of the primary branch flow channel is greater than the width of the secondary branch flow channel; the depth of the main flow channel is greater than the depth of the primary branch flow channel, and the depth of the primary branch flow channel is greater than the depth of the secondary branch flow channel.

6. The multi-layer planar tapered die head as described in claim 2, characterized in that: The main channel is arc-shaped and is located on the outside of each of the corresponding primary diversion channels, while each of the primary diversion ports is located on the inside of the main channel.

7. The multi-layer planar tapered die head as described in claim 6, characterized in that: Along the conveying direction of the main channel, the distances between the two primary diversion ports and the discharge end of the feed channel are equal, each primary diversion channel is arc-shaped, and each primary diversion channel has the same length.

8. The multi-layer planar tapered die head as described in claim 7, characterized in that: Along the conveying direction of the primary diversion channel, the distances between the two secondary diversion ports and their corresponding primary diversion ports are equal. Each of the secondary diversion channels is arranged in an arc shape, and the length of each secondary diversion channel is the same. Along the conveying direction of the secondary diversion channel, the distances between the two tertiary diversion ports and their corresponding secondary diversion ports are equal.

9. The multi-layer planar tapered die head as described in claim 1, characterized in that: The depth and width of the spiral groove gradually decrease from top to bottom.

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