CN117698088A - PET sheet extruder - Google Patents

Abstract

The invention relates to the technical field of plastic processing equipment, in particular to a PET sheet extruder, which comprises a platform, extrusion equipment, a melt pump and a die assembly, wherein the die assembly comprises a die body structure and a die lip structure, the die body structure comprises a first die body and a second die body arranged on one side of the first die body, the die lip structure comprises a deformation strip arranged at the bottom of the first die body, an extrusion bag is arranged in an inner groove at the outer side of the deformation strip, and the die assembly further comprises a diversion and pressure equalizing structure which is rotatably arranged above an inner cavity of the die body structure and is close to a feed inlet and is used for forcibly diverting the flowing-in molten material part to the two sides of the inner cavity so as to ensure that the pressure of the molten material flowing to the die lip structure is uniform; through setting up the extrusion bag, avoid die lip atress inhomogeneous condition that leads to inboard plane deformation is favorable to improving the degree of consistency of extruding thickness, through setting up reposition of redundant personnel pressure equalizing structure, edge pressure when increasing the material flow in the die cavity is favorable to extruding thickness's uniformity.

Description

PET sheet extruder

Technical Field

The invention relates to the technical field of plastic processing equipment, in particular to a PET sheet extruder.

Background

The PET plastic sheet is a new plastic product which is currently developed, the production is carried out by using extruder equipment, the thickness uniformity during sheet extrusion is an important ring for evaluating the quality of the product, the gap adjustment between the die lips of the existing partial PET sheet extrusion die usually adopts a structure of extruding one die lip by using a plurality of bolts, and the die lips are further deflected to be close to the die lips at the other side, so that the purpose of adjusting the gap and changing the extrusion thickness of the sheet is achieved.

In addition, as shown in fig. 12, after the molten material flow 6 enters the mold cavity 5, since the width of the mold cavity 5 is far greater than the width of the feeding pipe, the molten material flow 6 will be in a fan-shaped diffusion state when the molten material flows into the mold cavity 5 under high pressure, and the pressure of the molten material flow 6 is always higher than the pressure of the edges of the two sides of the feeding pipe at the center, so that when the molten material flow 6 flows into the lips, the thickness uniformity of the edges of the two sides of the PET sheet is difficult to ensure due to the lower pressure of the two sides and insufficient feeding.

Disclosure of Invention

In order to solve the problems of deformation of a die lip structure and uneven material flow pressure in a die cavity in the extrusion production of PET sheets and finally uneven sheet extrusion thickness, the invention provides a PET sheet extruder for solving the problems.

In order to achieve the above purpose, the present invention provides the following technical solutions:

the utility model provides a PET sheet extruder, includes platform, extrusion equipment, melt pump and mould subassembly, the mould subassembly passes through first pipeline connection melt pump, the melt pump passes through second pipeline connection extrusion equipment, the mould subassembly includes die body structure and die lip structure, the die body structure includes first die body and installs the second die body in its one side, the die lip structure is including installing the deformation strip in first die body bottom, be provided with the extrusion bag in the indent in the deformation strip outside, the shutoff strip is installed to the outside below of deformation strip, the die lip structure still includes the first die lip of installing in deformation strip bottom and installs the second die lip in second die body bottom;

the die assembly is characterized by further comprising a diversion and pressure equalizing structure which is arranged above the die body structure inner cavity and is close to the feed inlet, the diversion and pressure equalizing structure comprises a main shaft and an auxiliary shaft arranged at the middle part of the main shaft, sliding rails are arranged in grooves at the opposite positions of the two ends of the auxiliary shaft in a jogged mode, backflow prevention plates are mounted at the inner sides of the sliding rails in a jogged mode, the inner sides of the backflow prevention plates are connected to the outer circumferences in a jogged mode, resistance springs are fixedly mounted at the opposite jogged positions of the two ends of the middle part of the backflow prevention plates, the annular positions of the outer sides of the resistance springs are arranged at the positions of the inner sides of the sliding rails, and the ends of the other ends of the resistance springs are fixedly connected to the inner sides of the auxiliary shaft.

As a preferable scheme of the invention, a first half pipe is arranged in the middle of the top of the first die body, a second half pipe is arranged in the middle of the top of the second die body, a folding body between the first half pipe and the second half pipe is a connecting pipe, a pipe hoop is sleeved outside the connecting pipe, and the inside of the connecting pipe is sleeved outside one end of the first pipeline and is fastened through the pipe hoop.

As a preferable scheme of the invention, a first die cavity groove is arranged above the inner side of the first die body, a second die cavity groove is arranged above the inner side of the second die body, a cylindrical cavity is formed by folding the first die cavity groove and the second die cavity groove, the outer ends of the main shafts are respectively and correspondingly connected with the two ends of the cylindrical cavity in a rotating way, and the outer ends of the main shafts penetrate through the cylindrical cavity and are connected with a second motor;

the novel mold comprises a first mold body, wherein a third mold cavity groove is formed in the middle of the inner side of the first mold body, a fourth mold cavity groove is formed in the middle of the inner side of the second mold body, and a fifth mold cavity groove is formed in the lower portion of the inner side of the second mold body.

As a preferable scheme of the invention, the upper part, the lower part and the middle part of the interior of the first die body are respectively provided with a first heating pipe cavity, and the upper part, the middle part and the lower part of the interior of the second die body are respectively provided with a second heating pipe cavity.

As the preferable scheme of the invention, the die assembly further comprises end templates arranged at two ends of the die body structure, the lower parts of the inner sides of the end templates are correspondingly attached to two ends of the die lip structure, a pair of third hoisting rings are arranged at the top of each end template, first hoisting rings are arranged at two ends of the top of the first die body, and second hoisting rings are arranged at two ends of the top of the second die body.

As a preferable scheme of the invention, a third heating pipe cavity is arranged in the deformation strip, and a cooling pipe cavity is arranged in the plugging strip.

As a preferable scheme of the invention, the melt pump comprises a pump body, a discharge hole of the pump body is connected to the other end of the first pipeline, a feed inlet of the pump body is connected to one end of the second pipeline, a transmission shaft is arranged at the input end of the pump body, and the top end of the transmission shaft is connected with a first motor.

As a preferable scheme of the invention, the extruding equipment comprises an extruder main body, an extruding cylinder is arranged above the extruder main body, a discharge hole of the extruding cylinder is connected to the other end of the second pipeline, an exhaust pipe is arranged in the middle of the top of the extruding cylinder, and a feeding funnel is arranged on one side of the top of the extruding cylinder.

As a preferable scheme of the invention, the platform comprises a workbench arranged at the bottom of the extruder main body, a support is arranged on one side of the top of the workbench, the top end of the support is arranged at the bottom of the pump main body, a bracket is arranged on the top of the workbench above the support, a pair of first racks are arranged on the top of the bracket, and the tops of the first racks are respectively arranged on two sides of the first motor.

As a preferable scheme of the invention, the two ends of the bottom of one side of the bracket are respectively provided with a suspension arm, the lower parts of the inner sides of the suspension arms are respectively provided with a pair of pin shafts, the pin shafts are respectively correspondingly inserted into the first lifting ring and the third lifting ring adjacent to the first lifting ring, the second lifting ring and the third lifting ring adjacent to the second lifting ring, one end of the suspension arm is provided with a second rack below the outer sides of the suspension arms, and the top of a boss of the second rack is arranged at the bottom of the second motor.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, through the arrangement of the extrusion bag, when high-pressure fluid is filled into the extrusion bag and pressure is maintained, the extrusion bag can be expanded, so that the inner groove at the outer side of the deformation strip is expanded, the deformation strip is bent and deformed from the middle weak part, the first die lip is driven to deviate towards the second die lip, the first die lip is stressed at all positions in the deviation process, the condition that the flatness of the inner side plane is insufficient due to uneven stress is avoided, the flatness of the PET sheet during extrusion is improved, and the quality control is convenient.

2. According to the invention, the diversion pressure equalizing structure is arranged at the feed inlet of the die body structure and is used for dividing the inflow molten material flow into three parts, wherein the middle part is still directly flushed to the deep part in the inner cavity of the die body structure, and the two parts beside the middle part are respectively forced to be diverted to the two sides of the inner cavity, so that the pressure of the molten material flow flowing to the die lip structure is uniform due to the increased pressure at the edge, and the consistency of the thickness of extruded materials is further facilitated.

Drawings

FIG. 1 is a schematic perspective view of the present invention;

FIG. 2 is a schematic view of a module structure according to the present invention;

FIG. 3 is an exploded view of a portion of the structure of FIG. 2;

FIG. 4 is a schematic view of the structure of the first mold body and the second mold body according to the present invention;

FIG. 5 is another schematic view of the structure of FIG. 4;

FIG. 6 is a schematic diagram illustrating a configuration of a shunt equalizing structure according to an embodiment of the present invention;

FIG. 7 is a schematic side view of a die assembly of the present invention;

FIG. 8 is a schematic cross-sectional view of the structure at A-A of FIG. 2;

FIG. 9 is another schematic view of the structure of FIG. 1;

FIG. 10 is an enlarged schematic view of the structure at B in FIG. 9;

FIG. 11 is a schematic view of the installation of a mold assembly in an embodiment of the invention;

FIG. 12 is a schematic view showing a state in which a flow of molten material flowing into the inside of a cavity of a mold to exhibit fan-shaped diffusion, which is mentioned in the background of the invention;

FIG. 13 is a partial cross-sectional view of the auxiliary shaft of the present invention;

fig. 14 is a schematic view of the structure of the squeeze bag of the present invention.

1, a platform; 101. a work table; 102. a support; 103. a bracket; 104. a first frame; 105. a suspension arm; 106. a second frame; 2. an extrusion device; 201. an extruder body; 202. extruding a discharging tube; 203. an exhaust pipe; 204. a feed hopper; 3. a melt pump; 301. a pump body; 302. a transmission shaft; 303. a first motor; 4. a die assembly; 401. a first die body; 402. a second die body; 403. a first half pipe; 404. a second half pipe; 405. a pipe clamp; 406. a first cavity groove; 407. a second cavity groove; 408. a third cavity groove; 409. a fourth cavity groove; 410. a fifth cavity groove; 411. a main shaft; 412. an auxiliary shaft; 413. a slide rail; 414. a backflow prevention plate; 415. a resistance spring; 416. a first heating tube cavity; 417. a second heating tube cavity; 418. a deformation strip; 419. a third heating tube cavity; 420. extruding the bag; 421. a plugging strip; 422. cooling the lumen; 423. a first die lip; 424. a second die lip; 425. a first lifting ring; 426. a second lifting ring; 427. an end template; 428. a third lifting ring; 429. a second motor; 430. reinforcing ribs; 5. a mold cavity; 6. a molten material stream.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Examples:

as shown in fig. 1-12, an embodiment of the present invention provides a PET sheet extruder comprising a platform 1, an extrusion device 2, a melt pump 3, and a die assembly 4, wherein the die assembly 4 is connected to the melt pump 3 by a first pipe, and the melt pump 3 is connected to the extrusion device 2 by a second pipe.

In this embodiment, as shown in fig. 2 to 5, the die assembly 4 includes a die body structure including a first die body 401 and a second die body 402 mounted at one side thereof, the die lip structure includes a deformation bar 418 mounted at the bottom of the first die body 401, an extrusion bag 420 is disposed in an inner groove at the outer side of the deformation bar 418, a sealing bar 421 is mounted under the outer side of the deformation bar 418, and the die lip structure further includes a first die lip 423 mounted at the bottom of the deformation bar 418 and a second die lip 424 mounted at the bottom of the second die body 402.

The clearance adjustment between the die lips of the existing partial PET sheet extrusion die usually adopts a plurality of bolts to extrude a die lip structure on one side, and then the die lip structure is biased to be close to the die lip on the other side, thereby achieving the purpose of adjusting the clearance and changing the extrusion thickness of the sheet.

In this embodiment, referring to fig. 3 and 6, the mold assembly 4 further includes a shunt voltage equalizing structure rotatably disposed above the mold body structure cavity and proximate to the feed inlet, the shunt voltage equalizing structure includes a main shaft 411 and an auxiliary shaft 412 mounted at the middle of the main shaft 411, a sliding rail 413 is slotted in the opposite positions of two ends of the auxiliary shaft 412, a backflow preventing plate 414 is mounted at the inner side of the sliding rail 413 in a fitting manner, the inner side of the backflow preventing plate 414 is connected at the outer side circumference of 411 in a fitting manner, a resistance spring 415 is fixedly mounted at the opposite positions of two ends of the middle of the backflow preventing plate 414, the outer side annular position of the resistance spring 415 is disposed at the inner side slot position of the sliding rail 413, and the end of the other end of the resistance spring 415 is fixedly connected at the inner side of the auxiliary shaft 412. In this embodiment, the principle adopted by the backflow prevention plate 414 is a unidirectional backflow prevention principle, so that the description thereof will not be repeated here.

As shown in fig. 12, when the existing sheet extrusion die is used, after the molten material flow 6 enters the die cavity 5, the width of the die cavity 5 is far greater than the width of the feeding part of the die, so that the molten material flow 6 can be in a fan-shaped diffusion state when the molten material flows into the die cavity 5 at high pressure, and the pressure in the center is always higher than the pressures at the edges of the two sides, when the molten material flow 6 subsequently flows to the die lips, the situation that the thickness of the edges of the two sides of the PET sheet is difficult to ensure is caused due to insufficient pressure and insufficient feeding at the two sides, and the situation is particularly obvious at the initial stage of the primary extrusion process, only a part with a problem of cutting can be selected for ensuring the product quality, the production cost is improved, and although in the existing extrusion process, a melt pump 3 is connected in series to reduce the pulse phenomenon existing in the discharging of the screw extruder, the risk of the subsequent problem is further reduced, but the mode does not mean that the pressure is even when the molten material flow 6 flows to the die lips, the situation that the thickness of the sheet is uneven is caused by the pressure at the two sides of the die cavity 5 is further reduced, the pressure of the die body is not uniform, and the pressure is supposed to flow into the die cavity 6 at the two sides at the position of the die cavity is forced to flow, and the pressure is equal to flow to the two sides of the die cavity is forced to flow into the die cavity 6, and the structure is forced to flow at the side structures, and the two sides of the pressure is equal to the pressure of the die cavity 6.

Further, a first half pipe 403 is installed in the middle of the top of the first die body 401, a second half pipe 404 is installed in the middle of the top of the second die body 402, a closure body between the first half pipe 403 and the second half pipe 404 is a connecting pipe, a pipe hoop 405 is sleeved outside the connecting pipe, and the inside of the connecting pipe is sleeved outside one end of the first pipe and fastened through the pipe hoop 405.

Referring to fig. 4-5 and 7-8, a first cavity groove 406 is provided above the inner side of the first mold body 401, a second cavity groove 407 is provided above the inner side of the second mold body 402, a cylindrical cavity is formed by folding the first cavity groove 406 and the second cavity groove 407, the outer ends of the main shafts 411 are respectively and correspondingly connected to the two ends of the cylindrical cavity in a rotating mode, the outer ends of one end of the main shafts 411 penetrate through the cylindrical cavity and are connected with a second motor 429, a third cavity groove 408 is provided in the middle of the inner side of the first mold body 401, a fourth cavity groove 409 is provided in the middle of the inner side of the second mold body 402, and a fifth cavity groove 410 is provided below the inner side of the second mold body 402.

In this embodiment, the molten material flow 6 after being melted enters the cylindrical cavity through the first pipe and the connecting pipe, and is further split by the splitting and equalizing structure, so that the pressure when flowing into the third cavity groove 408 and the fourth cavity groove 409 is uniform, the pressure when flowing into the fifth cavity groove 410 is uniform, and the pressure when finally flowing into the die lip structure is also uniform, which is beneficial to improving the thickness uniformity when extruding the PET sheet.

Further, a first heating pipe chamber 416 is provided at both upper and lower portions of the interior of the first mold body 401, and a second heating pipe chamber 417 is provided at both upper, middle and lower portions of the interior of the second mold body 402.

When the molten material flow 6 enters the mold assembly 4, in order to ensure fluidity and the requirement of subsequent molding, it is generally necessary to inject flowing hot oil into the first heating pipe cavity 416 and the second heating pipe cavity 417, so that the molten material flow 6 is in a constant higher temperature state, and the above heating and heat preserving technical means belongs to conventional technical means commonly used in the field, and the working principle and manner thereof are not repeated herein.

In this embodiment, referring again to fig. 2-3, the die assembly 4 further includes end templates 427 mounted at two ends of the die body structure, the inner lower sides of the end templates 427 are correspondingly attached to two ends of the die lip structure, a pair of third lifting rings 428 are mounted at the top of the end templates 427, a first lifting ring 425 is mounted at two ends of the top of the first die body 401, and a second lifting ring 426 is mounted at two ends of the top of the second die body 402.

The first die body 401 and the second die body 402 are connected by bolts, the end die plate 427 and the die body structure are also connected by bolts, so that the subsequent disassembly and maintenance are facilitated, a corresponding through hole is arranged above the end die plate 427, so that the connection and the installation between the main shaft 411 and the second motor 429 are facilitated, and another corresponding through hole is arranged below the end die plate 427, so that the connection and the installation between the extrusion bag 420 and the high-pressure fluid pumping device are facilitated.

In this embodiment, in order to keep the heating temperature inside the die body structure uniform, a third heating chamber 419 is provided inside the deformation bar 418, and heating oil is introduced into the third heating chamber by adopting the prior art method, so as to achieve the purpose of heating the die body structure.

Further, the inside of the plugging strip 421 is provided with a cooling lumen 422, referring to fig. 8, when the inside of the extrusion bag 420 is filled with high-pressure fluid, the extrusion bag 420 is expanded and deformed, and the die body structure is in a heating and heat-preserving state, so that the extrusion bag 420 can absorb heat, and further the inside fluid is expanded again by heating under the condition of thermal expansion and cold contraction, so that the accuracy of the die lip clearance is affected.

Referring to fig. 9-10, in this embodiment, the melt pump 3 includes a pump body 301, a discharge port of the pump body 301 is connected to the other end of the first pipe, a feed port of the pump body 301 is connected to one end of the second pipe, a transmission shaft 302 is installed at an input end of the pump body 301, and a first motor 303 is connected to a top end of the transmission shaft 302.

In this embodiment, referring to fig. 1 and 9, the extrusion device 2 includes an extruder main body 201, an extrusion barrel 202 is installed above the extruder main body 201, a discharge port of the extrusion barrel 202 is connected to the other end of the second pipe, an exhaust pipe 203 is installed in the middle of the top of the extrusion barrel 202, and a feed hopper 204 is installed on one side of the top of the extrusion barrel 202, where the extrusion device 2 is preferably a screw extruder, and the working principle and mode thereof are not repeated herein.

In this embodiment, referring again to fig. 1 and 9, the platform 1 includes a table 101 mounted at the bottom of an extruder main body 201, a support 102 is mounted at one side of the top of the table 101, the top of the support 102 is mounted at the bottom of a pump main body 301, a support 103 is mounted above the support 102 at the top of the table 101, a pair of first frames 104 are mounted at the top of the support 103, and the tops of the first frames 104 are mounted at both sides of a first motor 303, respectively.

Further, referring to fig. 11, the boom 105 is mounted at two ends of one side bottom of the bracket 103, a pair of pins are mounted below the inner side of the boom 105, the pins are respectively inserted into the first lifting ring 425 and the third lifting ring 428 adjacent to the first lifting ring 425, the second lifting ring 426 and the third lifting ring 428 adjacent to the second lifting ring 426, the second frame 106 is mounted below the outer side of one end of the boom 105, and the top of the boss of the second frame 106 is mounted at the bottom of the second motor 429.

In this embodiment, the pin structure is preferably made of a twisted steel, and a plurality of adapted nuts may be screwed between the first lifting ring 425, the second lifting ring 426, and the third lifting ring 428, so as to achieve stable connection between the pin and each lifting ring.

During operation, firstly, materials are melt extruded through the extrusion equipment 2, and are injected into the die body structure through the first pipeline and the connecting pipe under the cooperation of the melt pump 3, at this time, the molten material flow 6 enters the cylindrical cavity, the second motor 429 drives the main shaft 411 to rotate clockwise, and in the process of rotating the main shaft 411, the auxiliary shaft 412 connected with the middle part is driven to rotate synchronously, the backflow preventing plate 414 connected with the auxiliary shaft 412 is pressed by the block at the groove position inside the auxiliary shaft 412 in the process of rotating the auxiliary shaft 412, so that the materials are extruded by the backflow preventing plate 414 to continue to circulate, the materials flowing back into the first gun groove 406 due to the backflow of the materials exert pressure on the backflow preventing plate 414 in the process, the backflow preventing plate 414 slides in the slide rail 413 arranged at the inner side of the main shaft 411 when being stressed in the anticlockwise direction, the resistance spring 415 is stressed in the process of sliding the backflow preventing plate 414, the backflow preventing plate 414 deforms and is provided on the backflow preventing plate 414 by itself when stressed, and the backflow preventing plate 414 is provided in the die cavity to the first groove 408, and the material flows into the die cavity through the second groove 408 after the backflow preventing plate is stressed by the first groove.

The above conditions avoid the leakage of the high-pressure molten material flow 6 from the joint between the first die body 401 and the second die body 402, so that the edge of the molten material flow 6 can have larger pressure by the operation of the above structure, and the problems in the prior art are avoided under the condition of uniform pressure, thereby being beneficial to ensuring the uniformity of the extrusion thickness of the sheet.

Further, when the molten material flows 6 gathered in the third cavity 408 and the fourth cavity 409 will automatically flow into the die lip structure and the die lip gap needs to be adjusted, as shown in fig. 7-8, high-pressure fluid is injected into the extrusion bag 420 first, and then the extrusion bag 420 is expanded and deformed due to the increase of internal pressure, so that the inner groove of the deformation bar 418 is extruded, under the cooperation of the sealing bar 421, the deformation bar 418 is bent and deformed at the weak middle position, so as to drive the first die lip 423 to close to the second die lip 424, after the gap size is qualified, pressure maintaining measures are adopted for the inside of the extrusion bag 420, and meanwhile flowing refrigerant is injected into the cooling pipe cavity 422, so that the temperature of the extrusion bag 420 is constant, the influence of the condition of thermal expansion and cold shrinkage is avoided, and the conditions that the prior adjusting technology is complicated and the thickness uniformity of the sheet is influenced are avoided through the scheme.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. A PET sheet extruder comprising a platform (1), an extrusion device (2), a melt pump (3) and a die assembly (4), characterized in that: the die assembly (4) is connected with the melt pump (3) through a first pipeline, the melt pump (3) is connected with the extrusion equipment (2) through a second pipeline, the die assembly (4) comprises a die body structure and a die lip structure, the die body structure comprises a first die body (401) and a second die body (402) arranged on one side of the first die body, the die lip structure comprises a deformation strip (418) arranged at the bottom of the first die body (401), an extrusion bag (420) is arranged in an inner groove at the outer side of the deformation strip (418), a reinforcing rib (430) is arranged in the inner groove of the extrusion bag (420), a plugging strip (421) is arranged below the outer side of the deformation strip (418), and the die lip structure further comprises a first die lip (423) arranged at the bottom of the deformation strip (418) and a second die lip (424) arranged at the bottom of the second die body (402).

The die assembly (4) further comprises a diversion pressure equalizing structure which is arranged above the die body structure inner cavity and is close to the feeding port, the diversion pressure equalizing structure comprises a main shaft (411) and an auxiliary shaft (412) which is arranged at the middle part of the main shaft (411), sliding rails (413) are arranged in grooves at the opposite positions of two ends of the auxiliary shaft (412), backflow prevention plates (414) are embedded and arranged at the inner sides of the sliding rails (413), resistance springs (415) are fixedly arranged at the opposite embedded positions of two ends of the middle part of the backflow prevention plates (414), the outer side annular positions of the resistance springs (415) are arranged at the inner sides of the sliding rails (413), and the ends of the other ends of the resistance springs (415) are fixedly connected at the inner sides of the auxiliary shaft (412).

2. A PET sheet extruder as claimed in claim 1, wherein: the utility model discloses a first die body, including first die body (401), second die body (402), first die body (403) are installed in the middle of the top of first die body (401), second half pipe (404) are installed in the middle of the top of second die body (402), the foldaway body between first half pipe (403) and second half pipe (404) is established to the connecting pipe, the outside cover of connecting pipe has ferrule (405), the inside cover of connecting pipe is in the outside of first pipeline one end and is fastened through ferrule (405).

3. A PET sheet extruder as claimed in claim 2, wherein: a first die cavity groove (406) is formed in the upper inner side of the first die body (401), a second die cavity groove (407) is formed in the upper inner side of the second die body (402), a cylindrical cavity is formed by folding the first die cavity groove (406) and the second die cavity groove (407), the outer ends of the main shafts (411) are respectively and correspondingly connected to the two ends of the cylindrical cavity in a rotating mode, and the outer ends of the main shafts (411) penetrate through the cylindrical cavity and are connected with a second motor (429);

a third die cavity groove (408) is formed in the middle of the inner side of the first die body (401), a fourth die cavity groove (409) is formed in the middle of the inner side of the second die body (402), and a fifth die cavity groove (410) is formed in the lower portion of the inner side of the second die body (402).

4. A PET sheet extruder as claimed in claim 3, wherein: the first heating pipe cavity (416) is arranged at the upper part, the lower part and the upper part of the inner part of the first die body (401), and the second heating pipe cavity (417) is arranged at the upper part, the middle part, the lower part and the upper part of the inner part of the second die body (402).

5. A PET sheet extruder as claimed in claim 1, wherein: the die assembly (4) further comprises end templates (427) arranged at two ends of the die body structure, the inner lower sides of the end templates (427) are correspondingly attached to two ends of the die lip structure, a pair of third hoisting rings (428) are arranged at the top of each end template (427), first hoisting rings (425) are arranged at two ends of the top of each first die body (401), and second hoisting rings (426) are arranged at two ends of the top of each second die body (402).

6. A PET sheet extruder as claimed in claim 1, wherein: a third heating pipe cavity (419) is formed in the deformation strip (418), and a cooling pipe cavity (422) is formed in the plugging strip (421).

7. A PET sheet extruder as claimed in claim 1, wherein: the melt pump (3) comprises a pump body (301), a discharge port of the pump body (301) is connected to the other end of the first pipeline, a feed port of the pump body (301) is connected to one end of the second pipeline, a transmission shaft (302) is mounted at the input end of the pump body (301), and a first motor (303) is connected to the top end of the transmission shaft (302).

8. A PET sheet extruder as claimed in claim 1, wherein: extrusion equipment (2) include extruder main part (201), extrusion feed cylinder (202) are installed to the top of extruder main part (201), the other end at the second pipeline is connected to the discharge gate of extrusion feed cylinder (202), install blast pipe (203) in the middle of the top of extrusion feed cylinder (202), feed hopper (204) are installed to top one side of extrusion feed cylinder (202).

9. A PET sheet extruder as claimed in claim 1, wherein: platform (1) is including installing workstation (101) in extruder main part (201) bottom, support (102) are installed to top one side of workstation (101), the bottom at pump body (301) is installed on the top of support (102), support (103) are installed in the top that is located support (102) of top of workstation (101), a pair of first frame (104) are installed at the top of support (103), the both sides at first motor (303) are installed respectively at the top of first frame (104).

10. A PET sheet extruder as claimed in claim 9, wherein: the lifting arm (105) is installed at both ends of support (103) one side bottom, a pair of round pins are all installed to the inboard below of lifting arm (105), round pins respectively correspond and alternate inside first lifting ring (425) and with first lifting ring (425) adjacent third lifting ring (428), and inside second lifting ring (426) and with second lifting ring (426) adjacent third lifting ring (428), one end second frame (106) are installed to the outside below of lifting arm (105), the boss top of second frame (106) is installed in the bottom of second motor (429).