阅读说明：本技术 一种双轴取向塑料管成型模具以及成型方法 (Forming die and forming method for biaxial orientation plastic pipe ) 是由 罗云 徐伟 赵天宝 谢剑 王翔宇 于 2021-01-25 设计创作，主要内容包括：本发明公开了一种双轴取向塑料管成型模具以及成型方法,属于塑料管成型技术领域。一种双轴取向塑料管成型模具,包括：第一端体、中体、第二端体、限位块、固定块以及通气管；第一端体、中体、第二端体沿轴线依次连接,限位块和固定块用于对管坯进行固定,通气管用于向管坯中通气,使管坯一次性完成轴向和径向的变形,能够一次性双轴取向,相对于原有的两道工序,大大缩短了制备周期,提高了生产效率,同时,采用空气直接对管坯进行扩胀,不会损坏管坯的表面以及不会影响最终产品的力学性能。(The invention discloses a forming die and a forming method for a biaxial orientation plastic pipe, and belongs to the technical field of plastic pipe forming. A biaxially oriented plastic tube forming die comprising: the air pipe comprises a first end body, a middle body, a second end body, a limiting block, a fixing block and an air pipe; first end body, well body, second end body connect gradually along the axis, stopper and fixed block are used for fixing the pipe, and the breather pipe is arranged in ventilating to the pipe, makes the pipe once only accomplish axial and radial deformation, can once only biax orientation, for original twice process, has shortened preparation cycle greatly, has improved production efficiency, simultaneously, adopts the air directly to expand the pipe, can not damage the surface of pipe and can not influence the mechanical properties of final product.)

1. A biaxially oriented plastic tube forming die, comprising: the device comprises a first end body (10), a middle body (20), a second end body (30), a limiting block (40), a fixing block (50) and a vent pipe (60);

the first end body (10), the middle body (20) and the second end body (30) are respectively provided with an inner cavity along an axis, the first end body (10), the middle body (20) and the second end body (30) are sequentially detachably connected along the axis, the inner cavities are sequentially communicated, and the diameter of the inner cavity of the middle body (20) is larger than that of the inner cavities of the first end body (10) and the second end body (30);

one end of the limiting block (40) is detachably connected with one end, far away from the middle body (20), of the first end body (10), and the other end of the limiting block (40) extends into the inner cavity of the first end body (10) and has a gap with the inner side wall of the first end body (10);

one end of the fixed block (50) is connected with one end, far away from the middle body (20), of the second end body (30), and the other end of the fixed block (50) extends into an inner cavity of the second end body (30);

the vent pipe (60) penetrates through the fixing block (50) and extends into the inner cavity, a plug (61) is arranged at one end, located in the inner cavity, of the vent pipe (60), and a plurality of vent holes (62) are formed in the side wall of the vent pipe (60).

2. A biaxially oriented plastic tube forming die according to claim 1, wherein the middle body (20) comprises a first connecting section (21) connected with the first end body (10) and a second connecting section (22) connected with the second end body (30);

a gap is formed between the first connecting section (21) and the second connecting section (22), a spring (23), a first elastic sleeve (24) and a second elastic sleeve (25) are arranged in the gap, two ends of the spring (23) are respectively connected with the first connecting section (21) and the second connecting section (22), and the spring (23) is positioned between the first elastic sleeve (24) and the second elastic sleeve (25);

one end of the first connecting section (21) close to the second connecting section (22) is provided with a sliding groove (26) with an annular cross section, one end of the second connecting section (22) close to the first connecting section (21) is provided with a sliding block (27) which is matched with the sliding groove (26) and has an annular cross section, the inner side wall of the second elastic sleeve (25) is flush with the inner side wall of the first connecting section (21) and the inner side wall of the second connecting section (22), and the outer side wall of the second elastic sleeve (25) is in contact with the inner side wall of the sliding block (27).

3. A biaxially oriented plastic tube forming die according to claim 1, wherein the end of the vent tube (60) located in the internal cavity extends into the internal cavity of the first end body (10).

4. A biaxially oriented plastic tube forming die according to claim 3, wherein the stopper (61) is conical; the limiting block (40) is provided with a through hole (41), the plug (61) extends into the through hole (41), and the conical surface of the plug (61) is in sealing fit with the limiting block (40).

5. A biaxially oriented plastic tube forming die according to claim 4, wherein the side wall of the through hole (41) is provided with a first chamfer (42) at a position close to the central body (20), the first chamfer (42) having a greater inclination with respect to the axial direction of the through hole (41) than the taper of the stopper (61).

6. A biaxially oriented plastic tube forming die according to claim 5, wherein the outer side wall of said stop block (40) is provided with a second chamfer (43) at a position close to said mid-body (20).

7. A biaxially oriented plastic tube forming die according to any one of claims 1 to 6, wherein a first non-slip mat (11) is provided at a position of the inner side wall of the first end body (10) opposite to the stopper (40); and a second anti-skid pad (31) is arranged on the inner side wall of the second end body (30), and the second anti-skid pad (31) is axially positioned between the middle body (20) and the fixed block (50).

8. A biaxially oriented plastic tube forming die according to claim 7, wherein the inner side wall of the first end body (10) is provided with a third chamfer (12) at a position close to the middle body (20) and the inner side wall of the second end body (30) is provided with a third chamfer (12) at a position close to the middle body (20), respectively, the major diameter of the third chamfer (12) is in accordance with the inner diameter of the middle body (20); the first end body (10) and the second end body (30) are respectively provided with an exhaust hole (13), and the exhaust holes (13) extend from the outer side of the corresponding end body to the corresponding third chamfer (12).

9. A method of forming a biaxially oriented plastic tube, comprising the steps of:

s1: preheating a tube blank to a high elastic state, preheating a biaxially oriented plastic tube forming die of any one of claims 1 to 8 to a set temperature, and preheating an expansion medium to the set temperature;

s2: putting the preheated pipe blank into a forming die of a biaxial orientation plastic pipe;

s3: introducing a preheated expansion medium into the breather pipe (60), and expanding the pipe blank under the action of the expansion medium and tightly adhering to the inner wall of the middle body (20);

s4: cooling the biaxial orientation plastic pipe forming die, and shaping the expanded pipe;

s5: opening a biaxial orientation plastic pipe forming die, and taking out the formed pipe;

s6: cutting two ends of the shaped pipe, and reserving a part opposite to the middle body (20) to obtain a product;

s7: and (5) standing the product storage pipe frame.

10. The method for molding a biaxially oriented plastic tube according to claim 9, wherein between the step S1 and the step S2, the method further comprises the step S11: pretreating the preheated pipe blank;

in step S2, the specific process of placing the preheated tube blank into a forming die of a biaxially oriented plastic tube is as follows: taking down a limiting block (40) of a biaxial orientation plastic pipe forming die, putting a preheated pipe blank into the biaxial orientation plastic pipe forming die and sleeving the pipe blank on the outer side of a vent pipe (60), then connecting the limiting block (40) with a first end body (10), enabling one end of the pipe blank to be in close contact with the outer side wall of the limiting block (40) and the inner side wall of the first end body (10), enabling the other end of the pipe blank to be in close contact with the end part of a fixing block (50), and enabling the outer side wall of the other end of the pipe blank to be in close contact with the inner side wall of a second end body (30);

between steps S3 and S4, step S12 is further included: and continuously introducing the preheated expansion medium into the vent pipe (60), and the first connecting section (21) and the second connecting section (22) slide relatively to each other, so that the tube blank is continuously deformed in the axial direction of the tube blank.

Technical Field

The invention relates to the technical field of plastic pipe forming, in particular to a forming die and a forming method of a biaxial orientation plastic pipe.

Background

The macromolecular chain segments of the polymer macromolecular material can be oriented along the direction of acting force under the action of certain temperature and external force, the macromolecular chain segments are further orderly arranged, so that the mechanical property of the material in the orientation direction is greatly improved, and the biaxially oriented plastic pipe can radially expand and axially expand the pipe blank so as to realize biaxial orientation. At present, when the biaxial orientation plastic pipe is prepared, the axial stretching is carried out through a tractor, and the radial expansion is carried out through expanding pieces such as conical pieces, but the preparation period is long and the production efficiency is low due to the fact that the two steps are carried out separately, and meanwhile, the introduction of the expanding pieces such as the conical pieces can rub against the pipe blank, so that the appearance quality and the mechanical property of a final finished product are affected.

Disclosure of Invention

The invention aims to provide a forming die and a forming method for a biaxial orientation plastic pipe, which aim to solve the problems that the existing biaxial orientation plastic pipe is low in production efficiency and appearance quality and mechanical property cannot be guaranteed during preparation.

The technical scheme for solving the technical problems is as follows:

a biaxially oriented plastic tube forming die comprising: the air pipe comprises a first end body, a middle body, a second end body, a limiting block, a fixing block and an air pipe;

the first end body, the middle body and the second end body are respectively provided with an inner cavity along the axis, the first end body, the middle body and the second end body are sequentially detachably connected along the axis, the inner cavities are sequentially communicated, and the diameter of the inner cavity of the middle body is larger than that of the inner cavities of the first end body and the second end body;

one end of the limiting block is detachably connected with one end of the first end body, which is far away from the middle body, and the other end of the limiting block extends into the inner cavity of the first end body and has a gap with the inner side wall of the first end body;

one end of the fixing block is connected with one end of the second end body, which is far away from the middle body, and the other end of the fixing block extends into the inner cavity of the second end body;

the breather pipe passes the fixed block and stretches into in the inner chamber, and the breather pipe is located the one end of inner chamber and is equipped with the end cap and the lateral wall of breather pipe is equipped with a plurality of bleeder vents.

When the forming die for the biaxial orientation plastic pipe is used for preparing the biaxial orientation plastic pipe, the pipe blank is subjected to expansion deformation in the die through gas, the pipe blank is subjected to axial and radial deformation at one time in the deformation process, the biaxial orientation can be carried out at one time, compared with the original two processes, the preparation period is greatly shortened, the production efficiency is improved, and meanwhile, the air is adopted to directly expand the pipe blank, so that the surface of the pipe blank cannot be damaged, and the mechanical property of a final product cannot be influenced.

The forming process of the biaxial orientation plastic pipe in the mould comprises the following steps: after the tube blank is put into the die, the tube blank is sleeved outside the vent pipe, one end of the tube blank is limited by the inner side wall of the second end body and the end part of the fixed block, the other closed end is sleeved outside the limiting block, the pipe blank is fixed by the extrusion action between the limiting block and the first end body, and is installed by limiting one end of the pipe blank and fixing the other end of the pipe blank, can shorten the installation time, avoid the problem that the temperature of the tube blank and the die is reduced too much due to overlong installation time of the tube blank, so that the biaxial orientation plastic tube can not be prepared smoothly, after the pipe blank is installed, hot air is introduced into the communicating air pipe, the hot air hole enters the pipe blank to expand the pipe blank until the pipe blank is tightly contacted with the inner wall of the middle body, the tube blank can deform in the radial direction and the axial direction in the expanding process, so that the axial deformation and the radial deformation can be completed at one time, and the biaxial orientation can be performed at one time.

Further, the middle body comprises a first connecting section connected with the first end body and a second connecting section connected with the second end body;

a gap is formed between the first connecting section and the second connecting section, a spring, a first elastic sleeve and a second elastic sleeve are arranged in the gap, two ends of the spring are respectively connected with the first connecting section and the second connecting section, and the spring is positioned between the first elastic sleeve and the second elastic sleeve;

the one end that first linkage segment is close to the second linkage segment is equipped with the cross-section and is annular spout, and the one end that the second linkage segment is close to first linkage segment is equipped with spout matched with and the cross-section is annular slider, and the inside wall of second elastic sleeve flushes with the inside wall of first linkage segment and second linkage segment, and the outside wall of second elastic sleeve contacts with the inside wall of slider.

The middle body is divided into the first connecting section and the second connecting section which can slide, so that the tube blank after collision can continue to deform along the axial direction, the spring is used for resetting the first connecting section and the second connecting end, the first elastic sleeve prevents foreign matters from entering the gap, and the second elastic sleeve prevents the tube blank from deforming to the gap, so that the surface quality of the final tube fitting is ensured.

Furthermore, one end of the vent pipe positioned in the inner cavity extends into the inner cavity of the first end body.

The vent pipe sequentially penetrates through the inner cavities of the second end body, the middle body and the first end body, so that hot gas is distributed more uniformly, a pipe blank can be uniformly deformed by the hot gas, and the biaxial orientation plastic pipe is better formed.

Furthermore, the plug is conical; the limiting block is provided with a through hole, the plug extends into the through hole, and the conical surface of the plug is in sealing fit with the limiting block.

The limiting block is provided with the through hole, so that the limiting block is easy to deform by extrusion, and when a tube blank is placed, the limiting block is easy to deform and enter the tube blank, so that the tube blank is extruded under the elastic action, and the fixation of the tube blank is realized. Meanwhile, the plug is used for plugging the through hole and extruding the limiting block, so that the limiting block can be in close contact with the tube blank.

Furthermore, a first chamfer is arranged at the position, close to the middle body, of the side wall of the through hole, and the inclination of the first chamfer relative to the axial direction of the through hole is larger than the taper of the plug.

The taper of the first chamfer angle is different from that of the plug, when the plug is contacted with the limiting block, the unique conical surface is contacted with one tip of the limiting block, and the tip and the conical surface are extruded to be more easily sealed.

Furthermore, a second chamfer is arranged at the position, close to the middle body, of the outer side wall of the limiting block.

The second chamfer angle is used for guiding, so that the limiting block can conveniently extend into the tube blank.

Furthermore, a first anti-skid pad is arranged at the position, opposite to the limiting block, of the inner side wall of the first end body; the inside wall of the second end body is provided with a second anti-skid pad, and the second anti-skid pad is axially positioned between the middle body and the fixing block.

The first non-slip mat and the second non-slip mat are used for preventing two ends of the tube blank from sliding in the manufacturing process, so that manufacturing failure caused by sliding is avoided.

Furthermore, a third chamfer is respectively arranged at the position of the inner side wall of the first end body close to the middle body and the position of the inner side wall of the second end body close to the middle body, and the major diameter of the third chamfer is consistent with the inner diameter of the middle body; the first end body and the second end body are respectively provided with an exhaust hole, and the exhaust holes extend from the outer side of the corresponding end body to the corresponding third chamfer.

The third chamfer of the invention has a guiding function on the tube blank in the deformation process, so that the tube blank can be continuously deformed, and the third chamfer is also used for extending the tube blank in the axial direction to ensure the axial orientation.

A method of forming a biaxially oriented plastics tube comprising the steps of:

s1: preheating the tube blank to a high-elastic state, preheating the biaxial orientation plastic tube forming die to a set temperature, and preheating an expansion medium to the set temperature;

s2: putting the preheated pipe blank into a forming die of a biaxial orientation plastic pipe;

s3: introducing a preheated expansion medium into the vent pipe, and expanding the pipe blank under the action of the expansion medium and tightly attaching the pipe blank to the inner wall of the middle body;

s4: cooling the biaxial orientation plastic pipe forming die, and shaping the expanded pipe;

s5: opening a biaxial orientation plastic pipe forming die, and taking out the formed pipe;

s6: cutting two ends of the shaped pipe, and reserving a part opposite to the middle body to obtain a product;

s7: and (5) standing the product storage pipe frame.

The invention adopts the forming die for the biaxial orientation plastic pipe to prepare the biaxial orientation plastic pipe, during the preparation process, the speed of installing the pipe blank is high, the heat loss is small, the temperature of the pipe blank and the die can be kept at the preparation temperature, the smooth preparation of the biaxial orientation plastic pipe is ensured, meanwhile, the axial deformation and the radial deformation are finished at one time through hot air, the working procedures are reduced, the preparation efficiency is improved, and meanwhile, the surface of the pipe blank cannot be damaged and the mechanical property of a final product cannot be influenced.

Further, between the step S1 and the step S2, the method further includes a step S11: pretreating the preheated pipe blank;

in step S2, the specific process of placing the preheated tube blank into a forming die of a biaxially oriented plastic tube is as follows: taking down a limiting block of a biaxial orientation plastic pipe forming die, putting the preheated pipe blank into the biaxial orientation plastic pipe forming die and sleeving the pipe blank on the outer side of a vent pipe, then connecting the limiting block with a first end body, enabling one end of the pipe blank to be in close contact with the outer side wall of the limiting block and the inner side wall of the first end body, enabling the other end of the pipe blank to be in close contact with the end part of a fixing block and enabling the outer side wall of the other end of the pipe blank to be in close contact with the inner side wall of a;

between steps S3 and S4, step S12 is further included: and continuously introducing the preheated expansion medium into the vent pipe, wherein the first connecting section and the second connecting section slide relatively, and the pipe blank continuously deforms in the axial direction of the pipe blank.

The method and the device can be used for pretreating the preheated tube blank, so that the surface of the tube blank is free from defects, and the quality of the tube blank is ensured. After the tube blank is expanded, the tube blank can be deformed continuously along the axis, and the application range and the practicability of the device are increased.

The invention has the following beneficial effects:

when the forming die for the biaxial orientation plastic pipe is used for preparing the biaxial orientation plastic pipe, the pipe blank is subjected to expansion deformation in the die through gas, the pipe blank is subjected to axial and radial deformation at one time in the deformation process, the biaxial orientation can be carried out at one time, compared with the original two processes, the preparation period is greatly shortened, the production efficiency is improved, and meanwhile, the air is adopted to directly expand the pipe blank, so that the surface of the pipe blank cannot be damaged, and the mechanical property of a final product cannot be influenced.

Drawings

FIG. 1 is a schematic structural view of a mold for forming a biaxially oriented plastic tube according to the present invention;

FIG. 2 is a schematic diagram of an exploded structure of the midbody of the present invention;

FIG. 3 is a schematic structural diagram of a limiting block according to the present invention;

FIG. 4 is a schematic view of the structure of the vent pipe of the present invention;

fig. 5 and 6 are schematic views of a biaxially oriented plastic tube as it is formed.

In the figure: 10-a first end body; 11-a first non-slip mat; 12-third chamfer; 13-exhaust hole; 20-midbody; 21-a first connection section; 22-a second connection section; 23-a spring; 24-a first elastic sleeve; 25-a second elastic sleeve; 26-a chute; 27-a slide block; 30-a second end body; 31-a second cleat; 40-a limiting block; 41-through holes; 42-first chamfer; 43-second chamfer; 50-fixing block; 60-a breather pipe; 61-plug; 62-air holes; 70-tube blank.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

Examples

Referring to fig. 1, a mold for forming a biaxially oriented plastic tube includes: the first end body 10, the middle body 20, the second end body 30, the limiting block 40, the fixing block 50 and the vent pipe 60. The first end body 10, the middle body 20 and the second end body 30 are respectively provided with an inner cavity along respective axes, the inner cavities penetrate through two ends of corresponding parts, the axes of the first end body 10, the middle body 20 and the second end body 30 are overlapped and the first end body 10, the middle body 20 and the second end body 30 are sequentially detachably connected along the axis direction, the axes of the first end body 10, the middle body 20 and the second end body 30 are the axes of the die, and meanwhile, the inner cavities of the first end body 10, the middle body 20 and the second end body 30 are sequentially communicated to form the inner cavity of the die. The limiting block 40 is disposed in the inner cavity of the first end body 10, and the fixing block 50 is disposed in the inner cavity of the second end body 30. In the present embodiment, the middle body 20 is coupled with the first and second end bodies 10 and 30 by bolts, respectively.

The inside wall of the first end body 10 is provided with a first non-slip mat 11, a third chamfer 12 is arranged at a position, close to the middle body 20, of the inside wall of the first end body 10, an exhaust hole 13 is arranged on the side wall of the first end body 10, and the exhaust hole 13 extends from the outer side of the first end body 10 to the corresponding third chamfer 12. The structure of the second end body 30 is the same as that of the first end body 10, and the direction of the second end body 30 is opposite to that of the first end body 10, the inner side wall of the second end body 30 is provided with a second non-slip mat 31, the position of the inner side wall of the second end body 30, which is close to the middle body 20, is also provided with a third chamfer 12, the side wall of the first end body 10 is also provided with an exhaust hole 13, and the exhaust hole 13 extends from the outer side of the second end body 30 to the corresponding third chamfer.

The inner cavity diameter of the first end body 10 is consistent with the inner cavity diameter of the second end body 30, meanwhile, the inner cavity diameter of the middle body 20 is larger than the inner cavity diameters of the first end body 10 and the second end body 30, the major diameter of the third chamfer 12 is consistent with the inner cavity diameter of the middle body 20, and the minor diameter of the third chamfer 12 is consistent with the inner cavity diameter of the first end body 10 and the inner cavity diameter of the second end body 30.

Referring to fig. 2, the middle body 20 includes a first connecting section 21 and a second connecting section 22, both of which are cylindrical, and the axes of the first connecting section 21 and the second connecting section 22 are coincident and the inner and outer diameters are the same. One end of the first connecting section 21 is connected with the first end body 10 through a bolt, the other end of the first connecting section 21 is connected with the second connecting section 22, and one end of the second connecting section 22 far away from the first connecting section 21 is connected with the second end body 30 through a bolt.

A gap is formed between the first connecting section 21 and the second connecting section 22, and a spring 23, a first elastic sleeve 24 and a second elastic sleeve 25 are arranged in the gap. Both ends of the spring 23, the first elastic sleeve 24 and the second elastic sleeve 25 are fixedly connected with the first connecting section 21 and the second connecting section 22, respectively, the second elastic sleeve 25 is positioned inside the first elastic sleeve 24, and the spring 23 is positioned between the first elastic sleeve 24 and the second elastic sleeve 25.

One end of the first connecting section 21 close to the second connecting section 22 is provided with a sliding groove 26 with an annular cross section, one end of the second connecting section 22 close to the first connecting section 21 is provided with a sliding block 27 which is matched with the sliding groove 26 and has an annular cross section, and when the sliding block slides in the sliding groove 26, the spring 23, the first elastic sleeve 24 and the second elastic sleeve 25 are deformed accordingly, so that the distance between the first connecting section 21 and the second connecting section 22 is increased or reduced. The sliding groove 26 and the sliding block 27, which are annular in cross section, can ensure smooth sliding between the first connecting section 21 and the second connecting section 22.

The inner side wall of the second elastic sleeve 25 is flush with the inner side walls of the first connecting section 21 and the second connecting section 22, the outer side wall of the second elastic sleeve 25 is in contact with the inner side wall of the sliding block 27, when the tube blank 70 expands, the tube blank 70 cannot enter a gap, and the quality of a final forming product is ensured.

Please refer to fig. 1 and fig. 3, one end of the limiting block 40 is located on one side of the first end body 10 far away from the middle body 20, and is connected with the first end body 10 through a bolt, the other end of the limiting block 40 extends into the inner cavity of the first end body 10, meanwhile, a gap is provided between the outer side wall of the limiting block 40 and the inner side wall of the first end body 10 for limiting the tube blank 70, and the limiting block 40 corresponds to the first anti-skid pad 11, the axis of the limiting block 40 coincides with the axis of the first end body 10, the limiting block 40 is provided with a through hole 41 along the axis direction thereof, and the deformation of the limiting block 40 is facilitated due to. A first chamfer 42 is arranged at the position, close to the middle body 20, of the side wall of the through hole 41, and a second chamfer 43 is arranged at the position, close to the middle body 20, of the outer side wall of the limiting block 40.

One end of the fixing block 50 is located at a side of the second end body 30 away from the middle body 20 and connected with the second end body 30 by a bolt, the other end of the fixing block 50 extends into an inner cavity of the second end body 30, and the second mat 31 is located between the fixing block 50 and the middle body 20 in the axial direction.

Referring to fig. 4, the vent pipe 60 sequentially passes through the fixing block 50, the inner cavity of the second end body 30 and the inner cavity of the middle body 20 and enters the inner cavity of the first end body 10, a plug 61 is arranged at one end of the vent pipe 60 extending into the inner cavity of the first end body 10, the plug 61 plugs the vent pipe 60, the plug 61 is conical, a conical tip of the plug 61 extends into the through hole 41, and the taper of the plug 61 is smaller than the axial inclination of the first chamfer 42 relative to the through hole 41, so that the conical surface of the plug 61 is in contact with the tip of the first chamfer 42, and the through hole 41 is conveniently sealed. The side wall of the breather pipe 60 is provided with a plurality of breather holes 62 for the intake of hot gas.

Referring to fig. 5 and 6, a method for forming a biaxially oriented plastic tube based on the above-mentioned biaxially oriented plastic tube forming mold is characterized by comprising the following steps:

s1: preheating the tube blank 70 to a high elastic state, preheating the biaxial orientation plastic tube forming die to a set temperature, and preheating an expansion medium to the set temperature;

s2: pretreating the preheated tube blank 70 to ensure the quality of the tube blank 70;

s3: the preheated tube blank 70 is put into a forming die of a biaxial orientation plastic tube, and the specific process comprises the following steps:

the limiting block 40 of the biaxial orientation plastic pipe forming die is taken down, the preheated pipe blank 70 is placed into the biaxial orientation plastic pipe forming die and sleeved outside the vent pipe 60, then the limiting block 40 is connected with the first end body 10, so that one end of the pipe blank 70 is in close contact with the outer side wall of the limiting block 40 and the inner side wall of the first end body 10, the other end of the pipe blank 70 is in close contact with the end part of the fixing block 50, and the outer side wall of the other end of the pipe blank 70 is in close contact with the inner side wall of the second end body 30.

S4: introducing preheated expansion medium such as air, nitrogen and the like into the breather pipe 60, and expanding the pipe blank 70 under the action of the expansion medium and tightly adhering to the inner wall of the middle body 20;

s5: continuously introducing the preheated expansion medium into the breather pipe 60, enabling the first connecting section 21 and the second connecting section 22 to slide relatively, and continuously deforming the tube blank 70 in the axial direction;

s6: cooling the biaxial orientation plastic pipe forming die, and shaping the expanded pipe;

s7: opening a biaxial orientation plastic pipe forming die, and taking out the formed pipe;

s8: cutting two ends of the shaped pipe, and reserving a part opposite to the middle body 20 to obtain a product;

s9: and standing the product storage rack for more than 24 hours.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.