CN104002465B - A kind of swollen-micro formula biaxial stretching pipe continuous shaping method and equipment - Google Patents

Abstract

The invention discloses a continuous forming method and equipment of an expansion-micro-shrinking type biaxially stretched pipe. The method is based on the balance of internal and external pressure, and first utilizes the pressure difference between the inner and outer cold air formed between the air inlet pipe and the cold air ring to make the pipe The embryo is radially expanded and the radial stretching ratio can be adjusted, and then the tube embryo is stretched axially to realize continuous preparation of biaxially stretched tubes; its equipment includes wall thickness adjustment components, cooling adjustment components and inflation components, The blowing assembly includes a mandrel, a die base, an air inlet pipe and a cold air ring. The mandrel is set in the die base, and a melt flow channel is formed between the mandrel and the die base. The outer periphery of the outlet of the channel, the air inlet pipe is set in the middle of the mandrel, and the air outlet end of the air inlet pipe is located inside the outlet of the melt flow channel; one side of the blowing component is provided with a wall thickness adjustment component, and the outer circumference of the blowing component is provided with Cooling conditioning components. The invention has a simple principle, realizes the adjustable size of the tube embryo and improves the product performance, and the product has a wide application range.

Description

A continuous forming method and equipment of expansion-shrinkage biaxially stretched tube

technical field

The invention relates to the technical field of pipe extrusion molding, in particular to an expansion-shrinkage biaxially stretched pipe continuous molding method and equipment.

Background technique

The stretching orientation process of polymer materials is the process in which the molecules of the material are arranged from disordered arrangement to ordered arrangement under the action of external force at a temperature between the glass transition temperature and the melting temperature. Due to the orderly arrangement of the polymer chains, the material changes from isotropy to anisotropy, that is, the strength of the material along the molecular orientation direction increases greatly. Utilizing the orientation characteristics of polymer materials, biaxially stretching the pipe can improve the hoop strength and axial strength of the pipe at the same time, and realize the improvement of the comprehensive performance of the pipe.

At present, the manufacturing technology of biaxially stretched pipe is divided into two categories: two-step processing method and one-step processing method.

The two-step processing method, also known as off-line process or batch (Inbatch) process, is characterized in that the extrusion of thick material embryos and biaxial stretching orientation are carried out in two steps. Orientation is achieved by placing the extruded and cooled pipe section (thick billet) in a mold and expanding it to the required size by heating and pressurizing.

The one-step processing method is also called the in-line process. On the pipe extrusion line, the extruded pipe (thick blank) is continuously expanded in the radial direction and stretched in the axial direction to achieve biaxial orientation, and then cooled and shaped into a biaxially stretched pipe.

The two-step processing method was developed earlier, the equipment and process are relatively simple, it can achieve a greater orientation effect, it is easy to achieve excellent performance, and the range of products that can be produced is wider, but the traditional two-step processing method has low production efficiency and is labor-intensive. and more energy. The one-step processing method has been developed in recent years. It has higher production efficiency and consumes less labor and energy. However, the equipment and process are more complicated, the stretching ratio is difficult to adjust, and the application range of the product is limited. At the same time, in the two-step and one-step processing, the polymer tube blank is directly cooled and shaped to form a biaxially stretched tube after a large orientation. In this process, the orientation of the polymer molecular chain has the greatest effect However, it will also cause relatively large internal stress in the biaxially stretched pipe, which will affect the final use effect of the pipe.

Aiming at the problems of narrow application range, difficult adjustment of stretching ratio, and large internal stress in the current one-step biaxial stretching and extrusion method and equipment, a new tube embryo expansion-shrinking double extrusion method based on internal and external pressure balance is developed. The method and equipment for continuous forming of axially stretched pipes are of great significance.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide an expansion-shrinkage biaxially stretched tube continuous forming method with adjustable tube blank size and wide application range.

Another object of the present invention is to provide an expansion-shrinkage type biaxially stretched tube continuous forming equipment for realizing the above method.

The technical solution of the present invention is: an expansion-shrinkage biaxially stretched pipe continuous forming method, based on the balance of internal and external pressure, the pressure difference between the inner and outer cold air formed between the air inlet pipe and the cold air ring is used first to make the pipe embryo Radially expand and realize the adjustable radial stretching ratio, and then carry out axial stretching on the tube embryo to realize continuous preparation of biaxially stretched tubes.

Before the axial stretching of the tube blank, the diameter of the bubble formed when the tube blank expands radially is adjusted by changing the cold air pressure in the air inlet pipe, and the tube wall formed by the axial stretching of the tube blank is adjusted by the wall thickness adjustment component. Thickness, adjust the length of the cooling section when the tube embryo is stretched axially through the cooling adjustment component.

The present invention is an expansion-shrinkage type biaxially stretched tube continuous molding equipment used in the above method, comprising a wall thickness adjustment assembly, a cooling adjustment assembly and an inflation assembly, the inflation assembly includes a mandrel, a die base, an air inlet Pipe and cold air ring, the mandrel is set in the base of the die, the melt flow channel is formed between the mandrel and the base of the die, the cold air ring is set on the outer periphery of the outlet of the melt flow channel, and the air inlet pipe is set in the middle of the mandrel , the air outlet end of the air inlet pipe is located inside the outlet of the melt channel; one side of the inflation assembly is provided with a wall thickness adjustment assembly, and the outer periphery of the inflation assembly is provided with a cooling adjustment assembly.

The cooling adjustment assembly includes a cooling adjustment handwheel, a cooling adjustment rod, a cross support frame, a cross positioning rod, a vacuum sizing sleeve and a sizing positioning pull rod, one end of the cooling adjustment rod is fixedly connected to the vacuum sizing sleeve, and the other end of the cooling adjustment rod After passing through the cross support frame, a cooling adjustment handwheel is set at the end, one side of the cross support frame is connected to the mandrel through a cross positioning rod, the outer circumference of the air inlet pipe is connected to the middle of the cross support frame, the bottom of the cross support frame, the bottom of the cold air ring It is connected with the bottom of the vacuum sizing sleeve through the sizing and positioning pull rod, and the vacuum sizing sleeve is slidably connected with the sizing and positioning pull rod.

The cooling adjusting rod is threadedly connected with the vacuum calibrating sleeve and locked with double nuts.

The vacuum sizing sleeve is located outside the cold air ring, on the vacuum sizing sleeve, a caliper sensor is arranged on the side opposite to the cold air ring, and the caliper sensor is arranged on the vacuum sizing sleeve through a sensor seat. The diameter of the film bubble can be measured in real time by the diameter sensor, so as to adjust the pressure of the cold air in the air inlet pipe, so that the diameter of the film bubble can be more stably maintained within the preset value range.

The space between the vacuum sizing sleeve and the cold air ring is the space for forming bubbles, and the space outside the cold air plug where the vacuum sizing sleeve is located is the cooling section when the tube embryo is axially stretched. When the cooling adjustment assembly is in use, the cooling adjustment handwheel can be adjusted, and the cooling adjustment rod drives the vacuum sizing sleeve to slide along the sizing positioning rod to adjust the length of the cooling section.

The wall thickness adjustment assembly includes a cold air plug, an air plug support frame, an air plug locking cap, a wall thickness adjustment handwheel, a wall thickness adjustment rod and a sizing sleeve support frame, and the sizing sleeve support is set on the outside of the cross support frame; The middle part of the plug is located in the air inlet pipe, one end of the cold air plug passes through the sizing sleeve support frame, and is fixedly connected with the air plug support frame through the air plug locking cap, and the other end of the cold air plug is located between the cold air ring and the vacuum sizing sleeve In the space between; one end of the wall thickness adjustment rod is fixedly connected with the sizing sleeve support frame, and the other end of the wall thickness adjustment rod passes through the air plug support frame, and the end is provided with a wall thickness adjustment hand wheel; the bottom of the sizing sleeve support frame is connected to the sizing sleeve support frame. Diameter positioning tie rod connection.

The wall thickness adjusting rod is threadedly connected with the support frame of the sizing sleeve, and locked by double nuts.

On the cold air plug, one end located in the space between the cold air ring and the vacuum sizing sleeve is a horizontal conical structure, and the conical outer wall of the cold air plug is provided with a plurality of through holes. The arrangement of multiple through holes can make the cold air in the air inlet pipe cool the tube embryo, and then enter the cold air plug from each through hole for recycling, realize recycling and reduce energy consumption.

On the cold air plug, there is a gap between the end portion located in the space between the cold air ring and the vacuum sizing sleeve and the vacuum sizing sleeve, and the gap is the outlet of the tube blank. When the wall thickness adjustment component is used, the wall thickness adjustment handwheel can be adjusted, and the cold air plug is driven to move left and right by the wall thickness adjustment rod and the air plug support frame, and the gap between the cold air plug and the vacuum sizing sleeve can be adjusted to adjust the wall thickness of the tube embryo. thick.

When the above expansion-shrinkage biaxial stretching tube continuous molding equipment is used, the molten material in the extruder enters the melt flow channel from the die base, the cold air ring blows cold air to the outer wall of the tube blank, and the high pressure of the air inlet tube The cold air is blown to the inner wall of the tube embryo at the same time, and the molten material at the outlet of the melt channel is cooled to between the glass transition temperature and the melting temperature by using the internal and external cold air, and at the same time, the glass transition temperature and the melting The tube embryo between the temperature is blown into a film bubble; then the tube embryo is shrunk to the preset size through the cold air plug and the vacuum sizing sleeve; finally, the blown tube embryo is extruded. In the above process, the diameter measuring sensor measures the outer diameter of the pipe in real time; turning the wall thickness adjustment handwheel can make the cold air plug move left and right to realize the wall thickness adjustment of the tube embryo; turn the cooling adjustment handwheel to make the vacuum sizing sleeve move left and right , to achieve the adjustment of the length of the cooling section. By adjusting the wall thickness and the length of the cooling section, it can meet the requirements of different materials and different processes, so that the equipment can be applied to the tube blank forming of various materials; changing the air pressure of the high-pressure cold air in the air inlet pipe can change the blowing The size of the membrane bubble of the expanded tube blank, that is, the radial stretch ratio is changed, so that the performance of the tube can be controlled.

Compared with the prior art, the present invention has the following beneficial effects:

The expanding-shrinking biaxially stretched tube continuous forming method and equipment have a simple principle, and are easy to operate and realize control. The specific performance is as follows: (1) By adjusting the pressure difference between the inner and outer cold air, the radial stretch ratio can be adjusted, and by adjusting the length of the cooling section of the tube blank, the performance of the tube can be adjusted, so that the equipment can meet different materials and different processes. At the same time, the performance of the tube can be controlled, and the application range is wide; (2) The micro-shrinkage of the tube blank can maintain the airtightness of the tube blank, and the wall thickness of the tube blank can be adjusted at the same time, which can be applied to different materials and different processes. It is suitable for a wide range of materials and processing, and at the same time, it relaxes the highly oriented polymer molecular chains, reduces the internal stress of the tube blank, and improves its performance; (3) The equipment is easy to disassemble and assemble, and can directly replace the extruder traditional molds.

Description of drawings

Fig. 1 is a structural schematic diagram of the present expanding-shrinking biaxially stretched tube continuous forming equipment.

detailed description

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example

In this embodiment, an expansion-shrinkage biaxially stretched pipe continuous forming method is based on the balance of internal and external pressure. Firstly, the pressure difference between the internal and external cold air formed between the air inlet pipe and the cold air ring is used to expand the pipe embryo radially and The radial stretching ratio can be adjusted, and then the tube embryo is stretched axially to realize the continuous preparation of biaxially stretched tubes.

Before the tube embryo is stretched axially, the diameter of the bubble formed when the tube embryo is radially expanded is adjusted by changing the cold air pressure in the air inlet pipe, and the thickness of the tube wall formed by the axial stretching of the tube embryo is adjusted through the wall thickness adjustment component. The length of the cooling section when the tube embryo is stretched axially is adjusted by the cooling adjustment assembly.

In this embodiment, an expansion-shrinkage biaxially stretched tube continuous molding equipment used in the above method includes a wall thickness adjustment assembly, a cooling adjustment assembly and an inflation assembly. As shown in Figure 1, the inflation assembly includes a mandrel 11. The die base 12, the air inlet pipe 7 and the cold air ring 13, the mandrel is set in the die base, the melt flow channel 20 is formed between the mandrel and the die base, and the cold air ring is set in the melt flow channel The outer circumference of the outlet, the air inlet pipe is set in the middle of the mandrel, and the air outlet end of the air inlet pipe is located inside the outlet of the melt flow channel; one side of the blowing component is provided with a wall thickness adjustment component, and the outer circumference of the blowing component is equipped with a cooling Adjustment components.

The cooling adjustment assembly includes a cooling adjustment handwheel 8, a cooling adjustment rod 14, a cross support frame 9, a cross positioning rod 10, a vacuum sizing sleeve 15 and a sizing positioning pull rod 16. One end of the cooling adjustment rod is fixedly connected with the vacuum sizing sleeve, and the cooling After the other end of the adjustment rod passes through the cross support frame, a cooling adjustment handwheel is set at the end. One side of the cross support frame is connected to the mandrel through the cross positioning rod. The bottom of the cold air ring is connected to the bottom of the vacuum sizing sleeve through the sizing and positioning pull rod, and the vacuum sizing sleeve is slidably connected to the sizing and positioning pull rod.

The cooling adjusting rod is threadedly connected with the vacuum calibrating sleeve and locked with double nuts.

The vacuum calibrating sleeve is positioned at the outside of the cold air ring, on the vacuum calibrating sleeve, a side opposite to the cold air air ring is provided with a diameter measuring sensor 19, and the diameter measuring sensor is arranged on the vacuum calibrating sleeve through the sensor seat 17. The diameter of the film bubble can be measured in real time by the diameter sensor, so as to adjust the pressure of the cold air in the air inlet pipe, so that the diameter of the film bubble can be more stably maintained within the preset value range.

The space between the vacuum sizing sleeve and the cold air ring is the space for forming bubbles, and the space outside the cold air plug where the vacuum sizing sleeve is located is the cooling section when the tube embryo is axially stretched. When the cooling adjustment assembly is in use, the cooling adjustment handwheel can be adjusted, and the cooling adjustment rod drives the vacuum sizing sleeve to slide along the sizing positioning rod to adjust the length of the cooling section.

The wall thickness adjustment assembly includes cold air plug 1, air plug support frame 2, air plug locking cap 3, wall thickness adjustment hand wheel 4, wall thickness adjustment rod 5 and sizing sleeve support frame 6, and the sizing sleeve support is set on the cross support outside the frame; the middle section of the cold air plug is located in the air inlet pipe, one end of the cold air plug passes through the sizing sleeve support frame, and is fixedly connected with the air plug support frame through the air plug locking cap, and the other end of the cold air plug is located between the cold air ring and the vacuum In the space between the sizing sleeves; one end of the wall thickness adjustment rod is fixedly connected with the sizing sleeve support frame, and the other end of the wall thickness adjustment rod passes through the air plug support frame, and the end is provided with a wall thickness adjustment hand wheel; the sizing sleeve supports The bottom of the frame is connected with the sizing and positioning pull rod.

The wall thickness adjusting rod is threadedly connected with the support frame of the sizing sleeve and locked with double nuts.

On the cold air plug, one end located in the space between the cold air ring and the vacuum sizing sleeve is a horizontal conical structure, and a plurality of through holes 21 are provided on the tapered outer wall of the cold air plug. The arrangement of a plurality of through holes can make the cold air in the air inlet pipe cool the tube blank 18, and then enter the cold air plug from each through hole for recycling, so as to realize recycling and reduce energy consumption.

On the cold air plug, there is a gap between the end part in the space between the cold air ring and the vacuum sizing sleeve and the vacuum sizing sleeve, and the gap is the outlet of the tube embryo. When the wall thickness adjustment component is used, the wall thickness adjustment handwheel can be adjusted, and the cold air plug is driven to move left and right by the wall thickness adjustment rod and the air plug support frame, and the gap between the cold air plug and the vacuum sizing sleeve can be adjusted to adjust the wall thickness of the tube embryo. thick.

When the expansion-shrinkage biaxial stretching tube continuous molding equipment is used, the molten material in the extruder enters the melt flow channel from the die base, and the cold air ring blows cold air to the outer wall of the tube embryo, and the air inlet tube The high-pressure cold air is blown to the inner wall of the tube embryo at the same time, and the molten material at the outlet of the melt flow channel is cooled to between the glass transition temperature and the melting temperature by using the internal and external cold air. The tube embryo between the melting temperature is blown into a film bubble; then the tube embryo is shrunk to the preset size through the cold air plug and the vacuum sizing sleeve; finally, the blown tube embryo is extruded. In the above process, the diameter measuring sensor measures the outer diameter of the pipe in real time; turning the wall thickness adjustment handwheel can make the cold air plug move left and right to realize the wall thickness adjustment of the tube blank; turn the cooling adjustment handwheel to make the vacuum sizing sleeve move left and right , to achieve the adjustment of the length of the cooling section. By adjusting the wall thickness and the length of the cooling section, it can meet the requirements of different materials and different processes, so that the equipment can be applied to the tube blank forming of various materials; changing the air pressure of the high-pressure cold air in the air inlet pipe can change the blowing The size of the membrane bubble of the expanded tube blank, that is, the radial stretch ratio is changed, so that the performance of the tube can be controlled.

As mentioned above, the present invention can be better realized. The above-mentioned embodiment is only a preferred embodiment of the present invention, and is not used to limit the scope of the present invention; Covered by the scope of protection required by the claims of the present invention.

Claims (9)

1. A continuous molding method for expanding-minor biaxially stretched pipes, characterized in that, based on the balance of internal and external pressures, the internal and external cold air pressure difference formed between the air inlet pipe and the cold air ring is first used to make the diameter of the pipe embryo Expand in the same direction and realize the adjustable radial stretching ratio, and then carry out axial stretching on the tube blank to realize continuous preparation of biaxially stretched tubes; wherein, the air outlet end of the air inlet pipe is located in the tube blank, and the cold air ring is located in the On the periphery of the tube embryo, the cold air provided by the air inlet pipe is blown to the inner wall of the tube embryo, and the cold air provided by the cold air ring is blown to the outer wall of the tube embryo. 2. An expansion-shrinkage type biaxially stretched tube continuous forming equipment for realizing the method of claim 1, characterized in that it includes a wall thickness adjustment assembly, a cooling adjustment assembly and an inflation assembly, and the inflation assembly includes Mandrel, die base, air inlet pipe and cold air ring, the mandrel is set in the die base, the melt flow channel is formed between the mandrel and the die base, and the cold air ring is set at the outlet periphery of the melt flow channel , the air inlet pipe is set in the middle of the mandrel, and the air outlet end of the air inlet pipe is located inside the outlet of the melt flow channel; one side of the inflation assembly is provided with a wall thickness adjustment assembly, and the outer periphery of the inflation assembly is provided with a cooling adjustment assembly. 3. An expanding-shrinking type biaxially stretched tube continuous forming equipment according to claim 2, characterized in that the cooling adjustment assembly includes a cooling adjustment handwheel, a cooling adjustment rod, a cross support frame, and a cross positioning rod 1. Vacuum sizing sleeve and sizing positioning pull rod. One end of the cooling adjustment rod is fixedly connected with the vacuum sizing sleeve. The positioning rod is connected with the mandrel, the outer circumference of the air inlet pipe is connected with the middle part of the cross support frame, the bottom of the cross support frame, the bottom of the cold air ring and the bottom of the vacuum sizing sleeve are connected by a sizing and positioning pull rod, and the vacuum sizing sleeve and the sizing and positioning pull rod Swipe to connect. 4. The expansion-shrinkage type biaxially stretched tube continuous forming equipment according to claim 3, characterized in that the cooling adjustment rod is screwed to the vacuum sizing sleeve and locked by double nuts. 5. According to claim 3, a kind of expanding-shrinking type biaxially stretched tube continuous forming equipment is characterized in that, the vacuum sizing sleeve is located on the outside of the cold wind ring, on the vacuum sizing sleeve, it is connected with the cold wind. A diameter measuring sensor is arranged on the opposite side of the ring, and the diameter measuring sensor is arranged on the vacuum calibrating sleeve through the sensor seat. 6. An expanding-shrinking type biaxially stretched tube continuous forming equipment according to claim 3, characterized in that, the wall thickness adjustment assembly includes a cold air plug, an air plug support frame, an air plug locking cap, a wall Thickness adjustment handwheel, wall thickness adjustment rod and sizing sleeve support frame, the sizing sleeve support is erected outside the cross support frame; the middle section of the cold air plug is located in the air inlet pipe, and one end of the cold air plug passes through the sizing sleeve support frame and passes through The air plug locking cap is fixedly connected with the air plug support frame, the other end of the cold air plug is located in the space between the cold air ring and the vacuum sizing sleeve; one end of the wall thickness adjustment rod is fixedly connected with the sizing sleeve support frame, and the wall thickness adjustment After the other end of the rod passes through the air plug support frame, the end is provided with a wall thickness adjustment handwheel; the bottom of the sizing sleeve support frame is connected with the sizing and positioning pull rod. 7. The expansion-shrinkage biaxially stretched tube continuous forming equipment according to claim 6, characterized in that the wall thickness adjusting rod is screwed to the sizing sleeve support frame and locked by double nuts. 8. According to claim 6, a kind of expand-minor type biaxially stretched tube continuous forming equipment is characterized in that, on the cold air plug, one end located in the space between the cold air ring and the vacuum sizing sleeve is The horizontal tapered structure has a plurality of through holes on the tapered outer wall of the cold air plug. 9. A kind of continuous forming equipment of expansion-shrinkage type biaxially stretched tube according to claim 6, characterized in that, on the said cold air plug, the end portion located in the space between the cold air ring and the vacuum sizing sleeve There is a gap between it and the vacuum sizing sleeve, and the gap is the outlet of the tube embryo.