Vacuum shaping extrusion production line for PEEK (Polyether-Ether-Ketone) pipes and regulation and control method

Abstract

The invention belongs to the technical field of production of PEEK (polyether-ether-ketone) pipes, and discloses a vacuum shaping extrusion production line for PEEK pipes and a regulation and control method. According to the production line, a pipe opening mold, a vacuum shaping cooling box, an eight-axis laser diameter measuring instrument, a traction device, a cutting device and a stacking device are sequentially arranged at one end of an extruder; the vacuum shaping cooling box is divided into a vacuum shaping cavity and a cooling cavity through a middle partition plate, wherein the vacuum shaping cavity is used for removing the internal stress of the PEEK pipe from the PEEK melting pipe through a vacuum-temperature-traction speed ratio joint control model, so that the ovality of the extruded pipe is not greater than 0.5%; and the cooling cavity is used for carrying out stepped cooling shaping on the extruded pipe output by the vacuum shaping cavity. The PEEK pipe blank is subjected to high-temperature cooling vacuum setting through the vacuum setting cooling box, it is guaranteed that the PEEK pipe has no internal stress, it can be guaranteed that the size of the PEEK pipe is stable, the production effect is improved, and the whole production line is simple in equipment and low in energy consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyether ether ketone pipe production, and particularly relates to a vacuum sizing extrusion production line and a control method for PEEK pipes. Background Art

[0002] Polyether ether ketone (PEEK), as a semi-crystalline high-performance thermoplastic special engineering plastic, not only has high strength, high rigidity, fatigue resistance and wear resistance, but also its mechanical properties can be comparable to those of metals, and even better in some aspects. At the same time, it has good tolerance to most chemical substances, including acids, alkalis, salts, organic solvents, etc., ensuring its stability in harsh chemical environments. It also has self-extinguishing properties, and the flame retardant grade reaches UL94V-0, which can effectively prevent the spread of flames in a fire. Its extremely low dielectric constant and dielectric loss enable PEEK to maintain good electrical insulation performance in high-frequency and high-temperature environments.

[0003] The vacuum sizing method is the most commonly used method for pipe extrusion. The sizing is directly carried out by using a vacuum sizing sleeve. Generally, there are several structures of the vacuum sleeve. One is the immersion type sizing sleeve, which is used for sizing and cooling of small-diameter pipes. In this case, the pipe blank is directly fed into the cooling water tank during extrusion. The other is the vacuum sizing sleeve structure, with cooling water pipes connected on both sides of the sizing sleeve to cool the sizing sleeve.

[0004] The existing vacuum sizing sleeve directly cools the sizing sleeve with cooling water. For general plastics, the melting temperature is generally in the range of 150 - 260 °C, with a low melting point, and the existing vacuum sizing sleeve can be used for direct water-cooling sizing. However, for PEEK materials, the melting temperature is generally 343 °C, and the glass transition temperature of PEEK is generally 143 °C. When using the water-cooling method, due to the large temperature difference, the pipe is rapidly cooled and sized, resulting in large internal stresses in the pipe. During subsequent processing, the dimensional stability is poor, the deformation is large, the ovality of the product is serious, the product performance and stability are reduced, and secondary aging treatment is required to remove the internal stresses in the pipe. During the treatment process, the pipe will be bent and deformed, and the energy consumption of the aging treatment equipment is high. Summary of the Invention

[0005] To overcome the problems existing in the related technologies, the disclosed embodiments of the present invention provide a vacuum sizing extrusion production line and a control method for PEEK pipes.

[0006] The technical solution is as follows: A vacuum sizing extrusion production line for PEEK pipes includes an extruder, and a pipe die, a vacuum sizing cooling box, an eight-axis laser diameter gauge, a traction device, a cutting device, and a stacking device are sequentially arranged at one end of the extruder; the vacuum sizing cooling box is divided into a vacuum sizing cavity and a cooling sizing cavity by an intermediate partition;

[0007] The vacuum sizing cavity is equipped with a sizing sleeve, and a spiral copper tube is wound around the outer diameter of the sizing sleeve. The inner circle of the spiral copper tube closely adheres to the outer diameter of the sizing sleeve. The spiral copper tube is provided with a spiral gap with a gap of 0.5 - 1 mm per turn, and the spiral copper tube is simultaneously used to undertake the dual functions of heating and vacuum adsorption channels;

[0008] The vacuum sizing cavity controls the sizing of the PEEK tube through a vacuum-temperature-drawing speed ratio joint control model to remove the internal stress of the PEEK pipe material, so that the ovality of the extruded pipe is not greater than 0.5%;

[0009] The sizing and cooling cavity is used to perform stepped cooling on the extruded pipe output by the vacuum sizing cavity (8).

[0010] Furthermore, the mathematical expression of the vacuum-temperature-drawing speed ratio joint control model is:

[0011]

[0012] In the formula, V is the vacuum degree, α is the temperature control coefficient, α = 0.32; T1 is the temperature of the sizing sleeve, T2 is the temperature of the cooling water, v is the drawing speed, β is the equipment constant, β = 5.6; γ is the tube blank expansion ratio control coefficient, γ = 1.8; is the tube blank expansion ratio,

[0013] A sizing sleeve is installed in the vacuum sizing cavity, and the sizing sleeve is fixed on the side wall of the vacuum sizing cavity through a conical surface locking structure;

[0014] The conical surface locking structure includes a front nut and a rear nut; the taper angles of the front nut and the rear nut are 15°, and an axial force of 300 N is applied through a hydraulic pre-tightening device to lock the sizing sleeve.

[0015] The sizing sleeve is a double-layer composite structure. The inner layer is a silicon nitride ceramic matrix made of silicon nitride ceramic material with a thickness of 3 mm; the outer layer is a copper-based composite material embedded with a circular copper wire braided mesh. The copper-based composite material is composed of 15% Cr, 2% Al2O3, and 83% Cu by mass ratio. The wire diameter of the circular copper wire braided mesh is 0.3 mm and 80 meshes;

[0016] The sizing sleeve is evenly provided with a plurality of circumferential slit-type suction grooves. The width of the circumferential slit-type suction grooves is 0.75 - 0.85 mm; the depth is 9 / 10 of the radius of the sizing sleeve, and the distribution angle of the circumferential slit-type suction grooves is 120°.

[0017] A spiral copper tube is wound around the outer diameter of the sizing sleeve. The inner circle of the spiral copper tube closely adheres to the outer diameter of the sizing sleeve. The spiral copper tube is simultaneously used to undertake the dual functions of heating and vacuum adsorption channels; the spiral copper tube is provided with a spiral gap with a gap of 0.5 - 1 mm per turn.

[0018] An insulating pipe is installed on the outer wall of the spiral copper pipe. The insulating pipe is processed with spiral grooves, and the spiral structure of the spiral grooves corresponds to the spiral gap of the spiral copper pipe, which is used to evacuate the sizing sleeve.

[0019] Vacuum suction ports are provided on the side wall of the vacuum sizing cavity. There is a vacuum glass cover plate on the upper side. The vacuum glass cover plate covers the sealing strip. There is a vacuum gauge and an electronically controlled intake valve on the vacuum glass cover plate to adjust the vacuum degree of the vacuum cavity during the pipe forming process. There is a vacuum cavity silicone gasket on one side of the vacuum sizing cavity. A round hole is opened in the center of the vacuum cavity silicone gasket, and the size is smaller than the outer diameter of the extruded pipe.

[0020] There is a cooling glass cover plate on the cooling cavity, and a water inlet is provided at the bottom. An inlet baffle is arranged at the upper end of the water inlet. A water return port is also installed in the cooling cavity to return the cooling water in the cooling cavity to form a complete cooling circuit. A cooling cavity silicone gasket is installed on the outer wall of the cooling cavity to seal the water in the cooling cavity. The height of the water return port of the cooling cavity is higher than the highest point of the outer diameter of the extruded pipe.

[0021] There is a water receiving tank at the rear side of the cooling cavity, and a water collecting port is provided at the lower part of the water receiving tank. The water collecting port is connected to the water return pipe through a hose.

[0022] The vacuum suction hose of the vacuum pump passes through the vacuum pipe hole and is connected to the vacuum suction port on the side wall of the vacuum sizing cavity.

[0023] On the side wall of the support at the bottom of the vacuum sizing and cooling box, there is an outlet pipe hole for the water pipe to pass through. The inlet pipe of the water pump is connected to the bottom of the side wall of the water tank. The outlet pipe of the water pump passes through the outlet pipe hole and is connected to the water inlet at the bottom of the cooling cavity. The water return port and the water return pipe are connected through a hose for the recovery of the cooling water to form a complete cooling water circuit.

[0024] A semiconductor refrigerating sheet for water cooling is installed in the water tank installed inside the support to control the temperature of the water in the water tank. And a drain pipe for water cleaning and a water replenishing pipe for supplementary water are provided on the side wall of the water tank.

[0025] Furthermore, a six-degree-of-freedom adjustment platform is additionally provided at the bottom of the vacuum sizing and cooling box to adjust the position of the box body of the vacuum sizing and cooling box. The six-degree-of-freedom adjustment platform includes a support frame.

[0026] A front and rear moving motor is installed on one side of the support frame.

[0027] A front, rear, left and right moving platform and a lifting and moving platform are installed on the support frame from bottom to top.

[0028] A left and right moving motor is installed on the front, rear, left and right moving platform, and a lifting and moving motor is installed on the lifting and moving platform.

[0029] Another object of the present invention is to provide a control method for a vacuum sizing extrusion production line for PEEK pipes, including:

[0030] S1. Simultaneously detect the diameter dimensions of the extruded pipe after cooling in the current eight directions through an eight-axis laser diameter gauge, and transmit the measured diameter values to the processor.

[0031] S2. The processor calculates the roundness of the extruded pipe after current cooling based on the input diameter dimensions of the extruded pipe. When the roundness is greater than 0.5%, trigger the regulation mode and issue regulation instructions for vacuum-temperature-drawing speed ratio.

[0032] S3. Adjust the intake electronic valve according to the regulation instructions for vacuum-temperature-drawing speed ratio, thereby adjusting the vacuum degree in the vacuum chamber, and real-time detect the vacuum value through a vacuum gauge. And according to the regulation instructions for vacuum-temperature-drawing speed ratio, the processor controls to reduce the speed of the tractor motor, reduce the drawing speed of the tractor, and control the temperature of the spiral copper pipe through the temperature control system of the oil temperature machine.

[0033] In step S3, controlling the temperature of the spiral copper pipe through the temperature control system of the oil temperature machine includes: increasing the temperature of the temperature controller of the oil temperature machine, starting the heating device to heat, regulating the electromagnetic control valve of the cooling water circuit of the oil temperature machine, reducing the cooling water flow of the oil temperature machine, reducing heat exchange, increasing the temperature of the oil temperature machine, and thereby increasing the temperature of the spiral copper pipe.

[0034] Combining all the above technical solutions, the beneficial effects of the present invention are as follows:

[0035] The extruder and the pipe die of the present invention extrude and form a molten pipe blank from the material. After being shaped by the vacuum sizing and cooling box, the laser diameter gauge detects the outer diameter dimensions of the passing PEEK pipes. Then the PEEK pipes pass through the traction device, cutting device, and stacking device in sequence for neat stacking. The PEEK pipe blank is subjected to high-temperature cooling and vacuum sizing through the vacuum sizing and cooling box, ensuring that the PEEK pipes have no internal stress, ensuring the dimensional stability of the PEEK pipes, improving the production effect, and the entire production line has simple equipment and low energy consumption.

[0036] There is a vacuum sizing cavity and a cooling cavity in the vacuum sizing and cooling box. In the vacuum sizing cavity, high-temperature oil is introduced into the spiral copper pipe. Because of the large contact area between the spiral structure and the sizing sleeve, the temperature of the sizing sleeve can be controlled by the oil temperature. The vacuum pump evacuates the vacuum sizing cavity through the vacuum suction port, and the vacuum degree of the cavity is ensured through the vacuum gauge and the intake valve, ensuring that the outer diameter of the pipe closely fits on the inner wall of the sizing sleeve. The cooling cavity forms a refrigerating circulating water cooling system through the water tank, water pump, water inlet, water return port, and return water pipe. The pipe undergoes gradient cooling through the vacuum sizing cavity and the cooling cavity, ensuring the stability of pipe forming, making the extruded pipe shrink evenly and having good dimensional stability.

[0037] The vacuum sizing and cooling box is equipped with a transparent glass cover plate, which enables operators to observe the internal working conditions, ensures the stable operation of the vacuum sizing box, and maintains the stability of high-speed operation. Description of the Drawings

[0038] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure;

[0039] Figure 1 It is a schematic diagram of a vacuum sizing and extrusion production line for PEEK pipes provided by an embodiment of the present invention;

[0040] Figure 2 It is a schematic cross-sectional structure diagram of the vacuum sizing and cooling box of the present invention provided by an embodiment of the present invention;

[0041] Figure 3 It is a schematic diagram of a partial structure of the vacuum sizing box of the present invention provided by an embodiment of the present invention;

[0042] Figure 4 It is a schematic diagram of the internal structure of the vacuum sizing and cooling box provided by an embodiment of the present invention;

[0043] Figure 5 It is a schematic diagram of the probe arrangement of an eight-axis laser diameter gauge provided by an embodiment of the present invention;

[0044] Figure 6 It is a top view of a six-degree-of-freedom adjustment platform of the present invention;

[0045] Figure 7 It is a front view of a six-degree-of-freedom adjustment platform of the present invention;

[0046] Figure 8 It is a flowchart of a control method for a vacuum sizing and extrusion production line for PEEK pipes provided by an embodiment of the present invention;

[0047] In the figure: 1. Extruder; 2. Die; 3. Vacuum sizing and cooling tank; 4. Eight-axis laser diameter gauge; 5. Traction device; 6. Cutting device; 7. Stacking device; 8. Vacuum sizing cavity; 9. Cooling cavity; 10. Front nut; 11. Rear nut; 12. Sizing sleeve; 13. Spiral copper tube; 14. Insulation pipe; 15. Vacuum suction port; 16. Sealing strip; 17. Vacuum glass cover plate; 18. Vacuum gauge; 19. Intake valve; 20. Cooling glass cover plate; 21. Vacuum chamber silicone gasket; 22. Cooling chamber silicone gasket; 23. Water inlet; 24. Water inlet baffle; 25. Water return port; 26. Support; 27. Vacuum pump; 28. Vacuum tube hole; 29. Water pump; 30. Water receiving tank; 31. Water collecting hole; 32. Water tank; 33. Pipe outlet hole; 34. Water return pipe; 35. Thermoelectric cooler; 36. Drain pipe; 37. Make-up water pipe; 38. Support frame; 39. Front and rear moving motor; 40. Front, rear, left and right moving platform; 41. Left and right moving motor; 42. Lifting and moving motor; 43. Lifting and moving platform. Specific implementation mode

[0048] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the specific implementation mode of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementations disclosed below.

[0049] The innovation points of the vacuum sizing extrusion production line and regulation method for PEEK pipes provided by the embodiments of the present invention are as follows: through the vacuum-temperature-traction speed ratio control model and stepped cooling, the pipe forming can be accurately controlled, significantly improving the dimensional accuracy of PEEK pipes (ellipticity ≤ 0.5%), reducing internal stress, and reducing the rejection rate and post-treatment cost. The spiral copper tube integrates the functions of heating and vacuum adsorption, simplifies the equipment structure, and reduces energy consumption and maintenance costs.

[0050] Example 1, as Figures 1 - 5 shown, the vacuum sizing extrusion production line for PEEK pipes provided by the embodiments of the present invention includes an extruder 1. One end of the extruder 1 is provided with a pipe die 2, a vacuum sizing and cooling tank 3, an eight-axis laser diameter gauge 4, a traction device 5, a cutting device 6, and a stacking device 7. The extruder 1 melts and plasticizes the material at high temperature. The pipe die 2 forms the molten material into a PEEK molten pipe blank, which is then transported to the next level through the vacuum sizing and cooling tank 3, the eight-axis laser diameter gauge 4, and the traction device 5. The eight-axis laser diameter gauge 4 detects the outer diameter size of the passing PEEK pipe to ensure that the outer diameter of the PEEK pipe meets the requirements. Then the PEEK pipe passes through the cutting device 6 and the stacking device 7, is cut after traction, and neatly stacked.

[0051] Exemplarily, the vacuum sizing and cooling box 3 is divided into a vacuum sizing cavity 8 and a cooling and sizing cavity 9 by an intermediate partition;

[0052] The vacuum sizing cavity 8 is equipped with a sizing sleeve 12, and a spiral copper tube 13 is wound around the outer diameter of the sizing sleeve 12. The inner ring of the spiral copper tube 13 is closely attached to the outer diameter of the sizing sleeve 12. The spiral copper tube 13 is provided with a spiral gap with a gap of 0.5 - 1 mm per turn, and the spiral copper tube 13 is simultaneously used to undertake the dual functions of heating and vacuum adsorption channels;

[0053] The vacuum sizing cavity 8 controls the sizing of the PEEK tube through a vacuum - temperature - drawing speed ratio control model to remove the internal stress in the PEEK tube, so that the ovality of the extruded tube is not more than 0.5%;

[0054] The cooling and sizing cavity 9 is used for step - cooling the extruded tube output from the vacuum sizing cavity 8.

[0055] Example 2, as Figure 2 shown, the vacuum sizing and cooling box 3 is divided into two cavities by an intermediate partition, namely a vacuum sizing cavity 8 and a cooling cavity 9. A sizing sleeve 12 is installed in the vacuum sizing cavity 8, and the sizing sleeve 12 is fixed on the side wall of the vacuum sizing cavity 8 through a front nut 10 and a rear nut 11;

[0056] The sizing sleeve 12 is a double - layer composite structure, as Figure 3 shown. The inner layer is made of silicon nitride ceramic material (high wear - resistance, low friction coefficient), and the outer layer is a copper - based composite material (embedded with an annular copper wire braided mesh).

[0057] Exemplarily, in the double - layer composite structure of the sizing sleeve 12, the silicon nitride ceramic material used in the inner layer forms a silicon nitride ceramic (Si3N4) matrix with a thickness of 3 mm. A diamond - like carbon film (DLC) is deposited on the surface of the silicon nitride ceramic (Si3N4) matrix to reduce the friction coefficient to 0.05. The PEEK melt has strong friction against the metal surface. The high hardness of the diamond - like carbon film in the present invention significantly reduces wear, extends the service life of the sizing sleeve, and reduces the maintenance frequency.

[0058] The outer layer uses a copper - based composite material (Cu + 15% Cr + 2% Al2O3), embedded with an annular copper wire braided mesh (wire diameter 0.3 mm, 80 meshes), and the thermal conductivity coefficient ≥ 220 W / (m·K).

[0059] In the present invention, the silicon carbide ceramic matrix has a small thermal expansion coefficient and small deformation at high temperatures, ensuring the dimensional stability of the sizing sleeve at high temperatures and guaranteeing the outer diameter uniformity of the tube. The high thermal conductivity of copper quickly conducts the heat from the inner layer, and can quickly control the temperature of the sizing sleeve.

[0060] After adopting this double-layer composite structure, the service life of the sizing sleeve 12 is extended from 2 weeks to 20 weeks, the ovality of the pipe is improved from ±0.3 mm to ±0.05 mm, the surface roughness Ra is reduced from 0.8 μm to 0.15 μm, and the production capacity is increased by 20%.

[0061] The sizing sleeve 12 is evenly provided with a plurality of circumferential slit suction grooves (such as Figure 3 ), and the distribution angle of the circumferential slit suction grooves is 120°. The width of the circumferential slit suction groove is 0.75 - 0.85 mm; the depth is 9 / 10 of the radius of the sizing sleeve.

[0062] Exemplarily, for the installation method of the sizing sleeve 12, a tapered surface locking structure is adopted, including a front nut 10 and a rear nut 11; the taper angles of the front nut 10 and the rear nut 11 are 15°, and an axial force of 300 N is applied through a hydraulic pre-tightening device to eliminate the thermal deformation gap.

[0063] Such as Figure 3 shown, a spiral copper tube 13 is wound around the outer diameter of the sizing sleeve 12. The inner circle of the spiral copper tube 13 closely adheres to the outer diameter of the sizing sleeve 12. The spiral copper tube 13 undertakes the dual functions of heating and vacuum adsorption channels at the same time. Its spiral gap design (the gap between each turn is 0.5 - 1 mm) is not only used for vacuum pumping, but also realizes uniform heating through the high thermal conductivity of the copper tube, avoiding local overheating caused by traditional electric heating.

[0064] A heat preservation tube 14 is installed on the outer wall of the spiral copper tube 13. The heat preservation tube 14 is processed with spiral grooves (such as Figure 3 ), and its spiral structure corresponds to the spiral gap of the spiral copper tube 13 so as to pump vacuum for the sizing sleeve;

[0065] The spiral copper tube 13 is made of a copper tube with good ductility and thermal conductivity.

[0066] A vacuum suction port 15 is provided on the side wall of the vacuum sizing cavity 8. There is a vacuum glass cover plate 17 above it. The vacuum glass cover plate 17 covers the sealing strip 16. There is a vacuum gauge 18 and an electronic control air inlet valve 19 on the vacuum glass cover plate 17 to adjust the vacuum degree of the vacuum cavity during the pipe forming process. There is a vacuum cavity silicone sealing pad 21 on one side of the vacuum sizing cavity 8. A round hole is opened in the center of the vacuum cavity silicone sealing pad 21, and the size is smaller than the outer diameter of the extruded pipe, which plays a sealing role during the extrusion process of the extruded pipe. A heat preservation cavity is formed during the forming process of the vacuum sizing cavity 8, which can further insulate the sizing sleeve 12, the spiral copper tube 13, and the heat preservation tube 14;

[0067] Such as Figure 4 shown, there is a cooling glass cover plate 20 on the cooling cavity 9, and a water inlet 23 at the bottom (such as Figure 3) At the upper end of the water inlet 23, there is a water inlet baffle 24. A water return port 25 is also installed in the cooling chamber 9. The water return port 25 returns the cooling water in the cooling chamber 9 to form a complete cooling loop. A cooling chamber silicone gasket 22 is installed on the outer wall of the cooling chamber 9 to seal the water in the cooling chamber 9 during the extrusion process of the extruded pipe. The height of the water return port 25 of the cooling chamber is higher than the highest point of the outer diameter of the extruded pipe, and the extruded pipe is completely immersed in the cooling water.

[0068] As Figure 2 shown, there is a water receiving tank 30 at the rear side of the cooling chamber 9. The water receiving tank 30 can be used to collect the flowing water in the cooling chamber 9 at the beginning of the extrusion of the extruded pipe. There is a water receiving port 31 at the lower part of the water receiving tank 30, and the water receiving port 31 is connected to the water return pipe 34 through a hose.

[0069] Exemplarily, the vacuum sizing and cooling box 3 is set as a square box, and both the vacuum sizing chamber 8 and the cooling chamber 9 are rectangular structures, which is convenient for setting the moving and adjusting device.

[0070] As Figure 2 shown, the vacuum suction hose of the vacuum pump 27 passes through the vacuum pipe hole 28 and is connected to the vacuum suction port 15 on the side wall of the vacuum sizing chamber 8 to vacuum the whole vacuum sizing chamber 8.

[0071] As Figure 5 shown, an eight-axis laser diameter gauge 4 is used for ovality detection;

[0072] On the side wall of the support 26 under the vacuum sizing and cooling box 3, there is an outlet pipe hole 33 for the water pipe to pass through. The inlet pipe of the water pump 29 is connected to the bottom of the side wall of the water tank 32, and the outlet pipe of the water pump 29 passes through the outlet pipe hole 33 and is connected to the water inlet 23 at the bottom of the cooling chamber 9. The water return port 25 and the water return pipe 34 are connected through a hose to recover the cooling water and form a complete cooling water loop.

[0073] A semiconductor refrigeration sheet 35 for water cooling is installed in the water tank 32 installed inside the support 26 to control the temperature of the water in the water tank 32. And there are a drain pipe 36 for water cleaning and a water replenishing pipe 37 for water replenishment on the side wall of the water tank 32.

[0074] Exemplarily, on the vacuum sizing chamber 8 and the cooling chamber 9, there are a vacuum glass cover 17 and a cooling glass cover plate 20 for observing the extrusion situation of the extruded pipe inside their respective cavities.

[0075] As Figure 1 shown, the cooled extruded pipe passes through the traction device 5 and enters the cutting device 6. The cutting device 6 is equipped with a pipe extrusion length measuring device (not shown) to cut out the required length of the extruded pipe.

[0076] The traction device 5 includes a traction machine motor;

[0077] The stacking device 7 automatically transfers the cut extruded pipes to the collection device and neatly arranges the extruded pipes.

[0078] Working principle: The PEEK molten tube blank enters the vacuum sizing and cooling box 3, undergoes stepped cooling and sizing through the vacuum sizing cavity 8 and the cooling cavity 9, heats the sizing sleeve 12 through the spiral copper tube 13, is sized through the sizing sleeve 12. High-temperature sizing can remove the internal stress in the PEEK pipe, ensure the roundness and uniform shrinkage of the extruded pipe, and good dimensional stability. Then, it is further cooled to a suitable temperature through the cooling cavity 9, and then undergoes traction, cutting, and stacking.

[0079] Another exemplary one is that the temperature of the spiral copper tube 13 can be controlled by the oil temperature machine temperature control system to prepare crystalline PEEK tubes.

[0080] Another exemplary one is to add a six-degree-of-freedom adjustment platform (electric movement + manual fine-tuning) at the bottom of the vacuum sizing and cooling box 3, as Figure 6 、 Figure 7 shown, to adjust the position of the box body of the vacuum sizing and cooling box 3 to ensure uniform wall thickness of the extruded pipe. The six-degree-of-freedom adjustment platform includes: a support frame 38, a front and rear movement motor 39, a front, rear, left, and right movement platform 40, a left and right movement motor 41, a lifting movement motor 42, and a lifting movement platform 43.

[0081] A front and rear movement motor 39 is installed on one side of the support frame 38;

[0082] The front, rear, left, and right movement platform 40 and the lifting movement platform 43 are installed on the support frame 38 from bottom to top;

[0083] A left and right movement motor 41 is installed on the front, rear, left, and right movement platform 40, and a lifting movement motor 42 is installed on the lifting movement platform 43.

[0084] Through the above embodiments, it can be seen that the present invention significantly improves the dimensional accuracy (ellipticity ≤ 0.5%) of PEEK pipes, reduces internal stress, reduces the scrap rate and post-treatment cost through the vacuum-temperature-traction speed ratio joint control model and the stepped cooling process. The spiral copper tube integrates heating and vacuum adsorption functions, simplifies the equipment structure, and reduces energy consumption and maintenance costs. The sizing sleeve adopts a double-layer structure of silicon nitride ceramic and copper-based composite material, which is wear-resistant and high-temperature resistant, and extends the service life. It can meet the needs of high-performance PEEK pipes in high-end fields such as medical catheters and aerospace precision components, break the import dependence, fill the domestic market gap, and seize the market share of high-value-added products.

[0085] The present invention realizes dynamic closed-loop regulation, fills the technical gap of the continuous extrusion process of high-precision PEEK pipes, especially in the field of stable production under complex working conditions.

[0086] Traditional processes rely on manual experience to adjust parameters and it is difficult to synchronously solve the contradiction between pipe deformation and internal stress. In the present invention, the octaxial laser diameter gauge 4 feeds back data in real time, triggering the control model to automatically optimize the vacuum degree, the temperature of the spiral copper pipe and the traction speed, overcoming the technical bottleneck that it is difficult to achieve both dimensional accuracy and mechanical properties in the extrusion of high-crystalline polymer pipes, and realizing for the first time the industrialized stable production with an ovality ≤ 0.5%.

[0087] The industry generally believes that heating and vacuum adsorption need to be realized by independent systems. However, this technology breakthroughly utilizes the spiral copper pipe with dual functions, and through the spiral gap design, it takes into account both heat conduction and vacuum adsorption efficiency, subverting the traditional collaborative thinking of multiple devices. The sizing sleeve adopts a ceramic-metal composite structure (traditionally mostly single metal), and the copper wire braided mesh is used to enhance the heat conduction uniformity, breaking the cognitive limitation that "it is difficult for high-hardness materials to take into account heat conductivity", providing a new paradigm for the design of ultra-precision extrusion dies.

[0088] Example 2, as Figure 8 shown, the control method provided by the embodiment of the present invention for a vacuum sizing extrusion production line for PEEK pipes includes:

[0089] S1, simultaneously detecting the diameter sizes of the extruded pipes cooled by the vacuum sizing cooling box 3 in the current eight directions through the octaxial laser diameter gauge 4, and transmitting the measured diameter values to the processor;

[0090] S2, the processor calculates the ovality of the extruded pipes cooled currently input according to the diameter sizes, and when the ovality is greater than 0.5%, triggers the control mode and issues the control instructions for the vacuum-temperature-traction speed ratio;

[0091] S3, adjusting the intake electronic valve 19 (as Figure 4 ) according to the control instructions for the vacuum-temperature-traction speed ratio, thereby adjusting the vacuum degree in the vacuum chamber 8, and detecting the vacuum value in real time through the vacuum gauge 18, and the processor controls to reduce the speed of the traction machine motor according to the control instructions for the vacuum-temperature-traction speed ratio, reducing the traction speed of the traction machine, and controlling the temperature of the spiral copper pipe 13 through the temperature control system of the oil temperature machine.

[0092] Exemplarily, in step S2, the control mode of the processor conducts the control of the vacuum-temperature-traction speed ratio through the vacuum-temperature-traction speed ratio control model;

[0093] The mathematical expression of the vacuum-temperature-traction speed ratio control model is:

[0094]

[0095] Wherein, V is the vacuum degree, unit: kPa; α is the temperature control coefficient, α = 0.32; T1 is the sizing sleeve temperature, unit: °C; T2 is the cooling water temperature, unit: °C; v is the drawing speed, unit: m / min; β is the equipment constant, β = 5.6; if the equipment is replaced, the parameters need to be re-tested, γ is the tube blank expansion ratio control coefficient, γ = 1.8; is the tube blank expansion ratio, constraint conditions:

[0096] Exemplarily, in step S3, the control method according to the control instruction of the vacuum-temperature-drawing speed ratio includes:

[0097] When it is detected that the ovality of the pipe is > 0.5%, it is automatically triggered: increase the vacuum degree by 10%, decrease the drawing speed by 0.2 m / min, and increase the oil temperature of the front section by 2 °C; adjustment period: optimize the parameters every 5 seconds;

[0098] In step S3, controlling the temperature of the spiral copper tube 13 through the temperature control system of the oil temperature machine includes: increasing the temperature controller temperature of the oil temperature machine, starting the heating device to heat, regulating the electromagnetic control valve of the cooling water circuit of the oil temperature machine, decreasing the cooling water flow of the oil temperature machine, reducing the heat exchange, increasing the temperature of the oil temperature machine, and thus increasing the temperature of the spiral copper tube 13.

[0099] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0100] The above is only a relatively preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention shall be covered by the protection scope of the present invention.

Claims

1. A vacuum shaping extrusion production line for PEEK pipes, comprising an extruder (1), one end of the extruder (1) being provided with a pipe die (2), a vacuum shaping cooling box (3), an eight-axis laser diameter measuring instrument (4), a traction device (5), a cutting device (6), and a stacking device (7) in sequence; characterized in that: The vacuum shaping and cooling box (3) is divided into a vacuum shaping chamber (8) and a cooling shaping chamber (9) by a middle partition; The vacuum shaping chamber (8) is provided with a sizing sleeve (12), the outer diameter of which is wound with a spiral copper tube (13), the inner circle of the spiral copper tube (13) is closely attached to the outer diameter of the sizing sleeve (12), and the spiral copper tube (13) is provided with a spiral gap of 0.5-1 mm per circle, and the spiral copper tube (13) is used to assume the dual functions of heating and vacuum adsorption channel; The vacuum shaping chamber (8) performs shaping control on the PEEK tube through a vacuum-temperature-traction speed ratio joint control model to remove the internal stress of the PEEK tube, so that the ovality of the extruded tube is not greater than 0.5%; The shaping cooling chamber (9) is used to perform step cooling on the extruded pipe output from the vacuum shaping chamber (8); The mathematical expression of the vacuum-temperature-traction speed ratio joint control model is: Wherein, V is the vacuum degree, α is the temperature control coefficient, α=0.32; T1 is the sizing sleeve temperature, T2 is the cooling water temperature, v is the traction speed, β is the equipment constant, β=5.6; γ is the tube expansion ratio control coefficient, γ=1.8; is the tube expansion ratio, 2. The vacuum shaping extrusion production line for PEEK pipes according to claim 1, characterized in that: A sizing sleeve (12) is installed in the vacuum shaping chamber (8), and the sizing sleeve (12) is fixed to the side wall of the vacuum shaping chamber (8) through a conical locking structure; The conical locking structure comprises a front nut (10) and a rear nut (11); the taper angle of the front nut (10) and the rear nut (11) is 15°, and an axial force of 300N is applied through a hydraulic pre-tightening device to lock the sizing sleeve (12).

3. The vacuum shaping extrusion production line for PEEK pipes according to claim 2, characterized in that: The sizing sleeve (12) is a double-layer composite structure, wherein the inner layer is a silicon nitride ceramic matrix made of silicon nitride ceramic material with a thickness of 3 mm; the outer layer is a copper-based composite material with an embedded annular copper wire braided mesh, wherein the copper-based composite material is composed of 15% Cr, 2% Al2O3 and 83% Cu in a mass ratio, and the annular copper wire braided mesh has a wire diameter of 0.3 mm and 80 meshes; The sizing sleeve (12) is evenly provided with a plurality of annular slit suction grooves, the width of the annular slit suction grooves is 0.75-0.85 mm, the depth is 9 / 10 of the radius of the sizing sleeve, and the distribution angle of the annular slit suction grooves is 120°.

4. The vacuum shaping extrusion production line for PEEK pipes according to claim 2, characterized in that: The outer wall of the spiral copper tube (13) is provided with a heat preservation tube (14), and the heat preservation tube (14) is processed with a spiral groove, and the spiral structure of the spiral groove corresponds to the spiral gap of the spiral copper tube (13), and is used to evacuate the sizing sleeve (12); A vacuum suction port (15) is provided on the side wall of the vacuum shaping chamber (8), and a vacuum glass cover plate (17) is provided on the upper side. The vacuum glass cover plate (17) covers the sealing strip (16). A vacuum gauge (18) and an electronically controlled air intake valve (19) are provided on the vacuum glass cover plate (17) to adjust the vacuum degree of the vacuum chamber during the tube forming process. A vacuum cavity silicone sealing pad (21) is provided on one side of the vacuum shaping chamber (8), and a circular hole is provided in the center of the vacuum cavity silicone sealing pad (21), and the size of the hole is smaller than the outer diameter of the extruded tube.

5. The vacuum shaping extrusion production line for PEEK pipes according to claim 1, characterized in that: A cooling glass cover plate (20) is provided on the cooling chamber (9), a water inlet (23) is provided at the bottom, a water inlet baffle (24) is provided at the upper end of the water inlet (23), a water return port (25) is also provided in the cooling chamber (9), the water return port (25) refluxes the cooling water in the cooling chamber (9) to form a complete cooling circuit, a cooling chamber silicone sealing pad (22) is provided on the outer wall of the cooling chamber (9) to seal the water in the cooling chamber (9), and the height of the water return port (25) of the cooling chamber is higher than the highest point of the outer diameter of the extruded pipe; A water receiving trough (30) is provided at the rear side of the cooling chamber (9), a water receiving port (31) is provided at the lower part of the water receiving trough (30), and the water receiving port (31) is connected to a water return pipe (34) through a hose; The vacuum hose of the vacuum pump (27) passes through the vacuum pipe hole (28) and is connected to the vacuum suction port (15) on the side wall of the vacuum shaping chamber (8).

6. The vacuum shaping extrusion production line for PEEK pipes according to claim 1, characterized in that: A pipe outlet hole (33) for a water pipe to pass through is provided on the side wall of the support (26) below the vacuum setting cooling box (3). The water inlet pipe of the water pump (29) is connected to the bottom of the side wall of the water tank (32). The water outlet pipe of the water pump (29) passes through the pipe outlet hole (33) and is connected to the water inlet (23) at the bottom of the cooling chamber (9). The water return port (25) and the water return pipe (34) are connected via a hose to recover cooling water, thereby forming a complete cooling water circuit.

7. The vacuum shaping extrusion production line for PEEK pipes according to claim 6, characterized in that: A semiconductor refrigeration plate (35) for water cooling is installed in the water tank (32) installed inside the support (26) to control the temperature of the water in the water tank (32), and a water drainage pipe (36) for water cleaning and a water replenishment pipe (37) for replenishing water are opened on the side wall of the water tank (32).

8. The vacuum shaping extrusion production line for PEEK pipes according to claim 1, characterized in that: A six-degree-of-freedom adjustment platform is also provided at the bottom of the vacuum shaping cooling box (3) to adjust the box position of the vacuum shaping cooling box (3), and the six-degree-of-freedom adjustment platform includes a support frame (38); A forward and backward moving motor (39) is installed on one side of the support frame (38); The support frame (38) is provided with a front-rear, left-right, and right-left moving platform (40) and a lifting moving platform (43) from bottom to top; A left-right moving motor (41) is installed on the front-back left-right moving platform (40), and a lifting moving motor (42) is installed on the lifting moving platform (43).

9. A control method for a vacuum shaping extrusion production line for PEEK pipes, characterized in that: The method is used to control the vacuum shaping extrusion production line for PEEK pipes according to any one of claims 1 to 7, and the method comprises: S1, using an eight-axis laser diameter measuring instrument (4) to simultaneously detect the diameter dimensions of the extruded pipe in eight directions after being cooled in a vacuum shaping cooling box (3), and transmitting the measured diameter values ​​to a processor; S2, the processor measures the ovality of the pipe based on the input diameter size of the extruded pipe after cooling. When the ovality is greater than 0.5%, the control mode is triggered and a vacuum-temperature-traction speed ratio control instruction is issued; S3, according to the vacuum-temperature-traction speed ratio control instruction, the air intake electronic valve (19) is adjusted to thereby adjust the vacuum degree in the vacuum chamber (8), and the vacuum value is detected in real time through the vacuum meter (18), and according to the vacuum-temperature-traction speed ratio control instruction processor, the speed of the traction machine motor is reduced by control to reduce the traction speed of the traction machine, and the temperature of the spiral copper tube (13) is controlled through the oil temperature machine temperature control system.

10. The control method for the vacuum shaping extrusion production line for PEEK pipes according to claim 9, characterized in that: In step S3, the temperature of the spiral copper tube (13) is controlled by the oil temperature machine temperature control system, including: increasing the temperature of the oil temperature machine thermostat, the heating device starts heating, regulating the electromagnetic control valve of the oil temperature machine cooling water circuit, reducing the oil temperature machine cooling water flow, reducing heat exchange, increasing the oil temperature machine temperature, and then increasing the temperature of the spiral copper tube (13).

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