Manufacturing method of medical polytetrafluoroethylene multi-cavity gas guide sieve tube

Abstract

The invention provides a manufacturing method of a medical polytetrafluoroethylene multi-cavity gas guide sieve tube. The manufacturing method comprises the following steps: connecting a plurality of charging barrels in the circumferential direction of a turntable rotating around the center of the turntable; adding a polytetrafluoroethylene preformed blank into the charging barrel; the charging barrel is connected with the die head; rotating a turntable, and rotating a charging barrel in which a polytetrafluoroethylene preform is arranged to a position coaxial with the core rod; the front end of the mandrel is connected with a mandrel; the core rod is pushed to move forwards, and the core mold enters the rear end of the charging barrel and penetrates through an inner hole of the polytetrafluoroethylene preformed blank; a push rod which is coaxial with the core rod and sleeves the periphery of the core rod axially moves forwards, the front end of the push rod enters the rear end of the charging barrel and applies pressure to the polytetrafluoroethylene preformed blank in the charging barrel, and the polytetrafluoroethylene preformed blank is extruded from a cavity between the die head and the core die; the disassembly and assembly frequency of the charging barrel is reduced, and the production efficiency is improved; the rotary table rotating mode can ensure that each charging barrel can be aligned with the piston at the front end of the push rod, the radial eccentricity of the charging barrels is reduced, and the quality of the manufactured cavity air guide screen pipe is higher.

Description

Technical Field

[0001] The invention belongs to the technical field of manufacturing polytetrafluoroethylene pipes, and in particular relates to a method for manufacturing a medical polytetrafluoroethylene multi-cavity air-conducting screen tube. Background Art

[0002] Polytetrafluoroethylene is a type of thermoplastic, known as the "king of plastics". It has the characteristics of high melting point, high temperature resistance, continuous use temperature of 260°C, resistance to chemical solvents, low friction coefficient, electrical insulation, good biocompatibility, no decomposition, no adverse reactions when implanted in the human body and no obvious aging. It is widely used in semiconductors, aerospace, electronics, machinery, medicine and other fields.

[0003] In recent years, intravascular interventional therapy is an emerging medical technology that uses interventional catheters to reach distant lesions in the body (such as the vascular cavities of the coronary arteries, brain, liver and kidneys) through the vascular lumen, and then injects diagnostic and therapeutic agents to achieve low-invasive treatment of distant parts of the body. It has become one of the three major clinical medicines alongside surgery and internal medicine. Interventional medicine is a minimally invasive medical field that uses medical imaging equipment to place precision instruments, such as special catheters and guidewires, to locally diagnose and treat pathological conditions in the body, and has received widespread attention.

[0004] Ideal interventional catheter materials should meet the following basic characteristics: 1. Good biocompatibility, especially blood compatibility, no harmful substances in the body; 2. Appropriate softness and good lubricity to reduce damage to blood vessel walls and blood cells; 3. Excellent torque conductivity and anti-kink; 4. Good compatibility with radiopaque agents; 5. Good processability; 6. Certain pressure resistance. Interventional catheters can be made into different shapes according to different uses and different application sites.

[0005] The traditional molding method of medical multi-cavity air-conducting screen tubes generally adopts extrusion molding. During extrusion, a preform is added to the barrel on the working platform, and then the piston end of the extrusion drive mechanism applies pressure to the preform in the barrel. The preform is extruded through the mold at one end of the barrel to form a multi-cavity air-conducting screen tube blank. The multi-cavity air-conducting screen tube blank is sintered to finally form a product. In this process, if you want to produce multi-cavity air-conducting screen tubes of different sizes, you need to replace barrels of different sizes, that is, remove the barrel from the working platform, and then reinstall the barrel of the new size. The disassembly and assembly process is cumbersome, which affects the production efficiency of the medical air-conducting screen tube. In addition, the disassembly and assembly of the barrel are all manual, and there is inevitably an error in the installation position. If the inner hole of the barrel is radially eccentric during installation, it will also affect the alignment of the piston end of the extrusion drive mechanism and the barrel, thereby affecting the preparation of the medical air-conducting screen tube. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for manufacturing a medical polytetrafluoroethylene multi-cavity gas-guiding screen tube in view of the deficiencies of the above-mentioned prior art. In the method for manufacturing a medical polytetrafluoroethylene multi-cavity gas-guiding screen tube, a rotating turntable is used to replace barrels of different sizes, thereby reducing the number of times the barrels are disassembled and assembled, and improving production efficiency. Since each barrel is distributed in the circumferential direction of the turntable, the rotating turntable method can ensure that each barrel can be aligned with the piston at the front end of the push rod, reducing the radial eccentricity of the barrel, so that the prepared cavity gas-guiding screen tube has higher quality.

[0007] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0008] A method for manufacturing a medical polytetrafluoroethylene multi-cavity air guide screen tube comprises the following steps:

[0009] Step 1: a plurality of barrels are connected at intervals in the circumferential direction of a turntable rotating around the center of the turntable; a polytetrafluoroethylene preform is added into the barrel; and a front end of the barrel is connected to a die head;

[0010] Step 2: Rotate the turntable until a barrel with a polytetrafluoroethylene preform inside is rotated to a position coaxial with the core rod;

[0011] Step 3: The front end of the core rod is connected to the core mold; the core rod is pushed forward axially, and the core mold enters the rear end of the barrel and passes through the inner hole of the polytetrafluoroethylene preform until the core mold is located inside the die head and the core rod stops moving;

[0012] Step 4: The push rod coaxial with the core rod and sleeved on the outer circumference of the core rod moves axially forward, the front end of the push rod enters the rear end of the barrel and applies pressure to the polytetrafluoroethylene preform inside the barrel, and the polytetrafluoroethylene preform is extruded from the cavity between the die head and the core die to obtain a polytetrafluoroethylene multi-cavity gas-guiding screen tube blank;

[0013] Step 5: Sintering the polytetrafluoroethylene multi-cavity gas-conducting screen tube blank to form a medical polytetrafluoroethylene multi-cavity gas-conducting screen tube.

[0014] As a further improved technical solution of the present invention, after step 4, there are:

[0015] Step 41: The core rod and the push rod are moved axially backward, so that the core mold, the core rod and the push rod are moved out of the barrel;

[0016] Step 42: Repeat steps 2-4 to complete the production of the polytetrafluoroethylene multi-cavity gas-conducting screen tube blank.

[0017] As a further improved technical solution of the present invention, a push rod push-pull transmission component for driving the push rod to move axially and a core rod push-pull transmission component for driving the core rod to move axially are installed on the working plane, and the center rotation of the turntable is connected above the working plane.

[0018] As a further improved technical solution of the present invention, a right end stopper, an upper fixing plate and a motor mounting plate are connected to the working plane;

[0019] The turntable includes a turntable 1 and a turntable 2, the center holes of the turntable 1 and the turntable 2 are both rotatably connected to the rotating load-bearing shaft, the two ends of the rotating load-bearing shaft are respectively connected to the right end block and the upper fixed plate, a plurality of barrels penetrate the turntable 1 and the turntable 2 and are connected to the turntable 1 and the turntable 2, and the plurality of barrels are evenly spaced and arranged along the circumferential direction of the turntable 1 and the turntable 2;

[0020] The push rod push-pull transmission component includes a push rod driving mechanism, a movable plate and a push rod. The upper fixed plate and the motor mounting plate are connected by a light rod, the movable plate is slidably connected to the light rod, the push rod driving mechanism is connected to the motor mounting plate, the driving end of the push rod driving mechanism is connected to the movable plate and is used to push and pull the movable plate, the movable plate is connected to the push rod, the push rod passes through the through hole on the upper fixed plate and the push rod can slide in the through hole on the upper fixed plate; the front end of the push rod is detachably connected to a piston, the piston on the push rod can extend into the barrel under the push of the movable plate, and the piston is in sliding contact with the inner wall of the barrel;

[0021] The core rod push-pull transmission component includes a core rod driving mechanism and a core rod; the core rod driving mechanism is connected to the motor mounting plate, the driving end of the core rod driving mechanism is connected to the core rod and is used to push and pull the core rod, the push rod is provided with an axial hole extending along the length direction of the push rod, the core rod passes through the axial hole of the push rod and the through hole on the piston and the core rod can slide in the axial hole of the push rod and the through hole on the piston, the die head is detachably connected to the barrel through the die head fixing ring, and the core mold is detachably connected to the core rod;

[0022] The axes of the core rod, the push rod, the piston and the core mold are located on the same straight line, and the axes of the inner hole in the die head and the inner hole in the barrel are located on the same straight line.

[0023] As a further improved technical solution of the present invention, the multiple barrels include a barrel with a diameter of 40 mm, a barrel with a diameter of 45 mm and a barrel with a diameter of 50 mm, and the lengths of all of them are 90 cm; the multiple barrels are all used to add polytetrafluoroethylene preforms, and the outer circle of the polytetrafluoroethylene preforms is gap-matched with the inner wall of the barrel.

[0024] As a further improved technical solution of the present invention, there are two push rod driving mechanisms, and the driving ends of the two push rod driving mechanisms are connected to the movable plate after passing through the reserved through holes on the motor mounting plate. The movable plate is threadedly connected to one end of the push rod, and the other end of the push rod is threadedly connected to the piston.

[0025] As a further improved technical solution of the present invention, there are two core rod driving mechanisms, and the driving ends of the two core rod driving mechanisms are connected to the sliding block after passing through the reserved through holes on the motor mounting plate, one end of the core rod is connected to the middle of the sliding block after passing through the through hole in the middle of the motor mounting plate, the core rod is slidably connected to the through hole in the middle of the motor mounting plate, and the core rod is slidably and sealedly connected to the through hole on the piston.

[0026] As a further improved technical solution of the present invention, the core rod is made of 304 stainless steel; the push rod driving mechanism adopts electric cylinder 1, which is connected to the motor mounting plate through a cylinder front flange and bolts; the core rod driving mechanism adopts electric cylinder 2, which is connected to the motor mounting plate through a cylinder front flange and bolts.

[0027] As a further improved technical solution of the present invention, the core mold includes a threaded area, a conical area and multiple core rods, the threaded area, the conical area and the multiple core rods are fixedly connected in sequence, and the threaded area is threadedly connected to the end hole on the core rod.

[0028] As a further improved technical solution of the present invention, the number of the core rods is an even number, the length of the core rods is 20-30% of the total length of the core mold, and the gap between each core rod is 0.5-1 mm.

[0029] The beneficial effects of the present invention are:

[0030] 1. In the manufacturing method of the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube, a rotating turntable is used to replace barrels of different sizes, thereby reducing the number of times the barrels are disassembled and assembled, and improving production efficiency; since each barrel is distributed in the circumferential direction of the turntable, the rotating turntable method can ensure that each barrel can be aligned with the piston at the front end of the push rod, reducing the radial eccentricity of the barrel, so that the prepared cavity gas-guiding screen tube has higher quality.

[0031] 2. The present invention includes a rotatable barrel and a sliding block connected to a core rod. One end of all barrels on turntable 1 and turntable 2 can be pre-fixed and installed with a die of matching size through a die fixing ring and bolts. Then, the preform is added to the other end of the barrel to be used. One end of the core rod is threadedly connected to a core mold of a suitable size, which can drive electric cylinder 1 and electric cylinder 2 to move and realize extrusion. During the overall process, the bolt connection between the die fixing ring and the barrel and the threaded connection between the core mold and the core rod make the assembly and disassembly of the die and the core mold simple and convenient, and the replacement efficiency of the die and the core mold is high. In addition, when replacing the barrel, it is only necessary to rotate turntable one and turntable two and align the appropriate barrel with the push rod (or the through hole of the upper fixed plate), which saves the operation of disassembling the old barrel and then installing the new barrel in the original position of the old barrel, reduces the number of times the barrel is disassembled and assembled, is convenient and fast, saves time and effort, and the outer circle of the polytetrafluoroethylene preform and the small gap between the inner wall of the barrel are matched, which reduces the shaking of the polytetrafluoroethylene preform in the barrel, reduces eccentricity, improves concentricity, and prevents large radial eccentricity with the core rod, thereby ensuring the appearance quality and wall thickness uniformity of the medical multi-cavity gas guide screen tube. At the same time, the device is suitable for large-scale industrialization.

[0032] 3. When the electric cylinder 1 in the push rod driving mechanism is turned on, the electric cylinder 1 pushes the push rod toward the barrel, and the piston of the push rod enters the barrel, and the outer circle of the piston slides with the inner wall of the barrel in a sealed manner. At this time, the axis of the piston is aligned with the axis of the barrel. Since the axes of the piston, core rod, push rod, and core mold are located on the same straight line, the axis of the inner hole of the die head and the axis of the inner hole of the barrel are located on the same straight line, therefore, it is ensured that the axis of the core mold and the axis of the die head are located on the same straight line, and the core mold is located at the center of the die head, further ensuring the concentricity of the polytetrafluoroethylene preform and the core mold, the piston of the push rod pushes the polytetrafluoroethylene preform in the barrel, and the polytetrafluoroethylene preform enters the cavity between the die head and the core mold, and then extrude a multi-cavity pipe blank from the outlet of the die head, that is, a medical multi-cavity gas guide screen tube blank, and then sintered by a sintering device, and finally formed a medical multi-cavity gas guide screen tube with uniform inner hole and wall thickness.

[0033] 4. The present invention can meet the use requirements of three preforms with different diameters. The barrel length can be added with three 30 cm long polytetrafluoroethylene preforms, reducing the number of feeding times, and can form a polytetrafluoroethylene multi-lumen tube with a longer length at one time. The medical multi-lumen tube has a uniform wall thickness and good dimensional stability. In addition, the number of barrels on the turntable 1 and the turntable 2 of the present invention is not limited to 3, and can be set according to requirements. The barrels installed on the turntable 1 and the turntable 2 are commonly used barrels.

[0034] 5. The push rod of the present invention is threadedly connected to the piston, which is convenient for replacing pistons with different outer diameters on the push rod. The core mold and the core rod are threadedly connected, which is also convenient for replacing core molds of different sizes on the core rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the three-dimensional structure of the manufacturing device used in the manufacturing method of the present invention.

[0036] Figure 2 It is a three-dimensional structural schematic diagram of the horizontal extruder structure in the manufacturing device used in the manufacturing method of the present invention.

[0037] Figure 3 It is a plan view of the structure of a horizontal extruder in the manufacturing apparatus used in the manufacturing method of the present invention.

[0038] Figure 4 for Figure 3 Middle AA section view.

[0039] Figure 5 for Figure 4 A partial enlarged view of middle A.

[0040] Figure 6 It is a structural schematic diagram of the core mold in the manufacturing device used in the manufacturing method of the present invention.

[0041] Figure 6 (a) is a cross-sectional view of the core mold.

[0042] Figure 6 (b) is a side view of the core mold.

[0043] Figure 7 It is a schematic diagram of the structure of a twelve-cavity gas-conducting test tube for Chinese medicine of the present invention.

[0044] In the figure: 1, sintering equipment; 2, right end stopper; 3, bearing shaft fixing block; 4, turntable 1; 5, rotating bearing shaft; 6, barrel; 7, turntable 2; 8, upper fixing plate; 9, polished rod; 10, push rod; 11, movable plate; 12, core rod; 13, motor mounting plate; 14, cylinder front flange; 15, sliding block; 16, push rod driving mechanism; 17, core rod driving mechanism; 18, support rod; 19, working plane; 20, die head; 201, conical inner hole; 202, cylindrical inner hole; 21, die head fixing ring; 22, core mold; 221, threaded area; 222, conical area; 223, core rod; 23, piston. DETAILED DESCRIPTION

[0045] The specific embodiments of the present invention are further described below according to the accompanying drawings:

[0046] A method for manufacturing a medical polytetrafluoroethylene multi-cavity air guide screen tube comprises the following steps:

[0047] Step 1: Figure 1As shown, a plurality of barrels 6 are connected at intervals in the circumferential direction of the turntable rotating around the center of the turntable; a suitable barrel 6 is selected, and the polytetrafluoroethylene preform is added into the barrel 6; the front end of the barrel 6 is connected to the die head 20;

[0048] Step 2: Rotate the turntable until a barrel 6 containing a polytetrafluoroethylene preform is rotated to a position coaxial with the core rod 12;

[0049] Step 3: The front end of the core rod 12 is connected to the core mold 22; the core rod 12 is pushed axially forward, and the core mold 22 enters the rear end of the barrel 6 and passes through the inner hole of the polytetrafluoroethylene preform until the core mold 22 is located inside the die head 20, and the core rod 12 stops moving;

[0050] Step 4: The push rod 10 coaxial with the core rod 12 and sleeved on the outer periphery of the core rod 12 moves axially forward, the front end of the push rod 10 enters the rear end of the barrel 6 and applies pressure to the polytetrafluoroethylene preform inside the barrel 6, and the polytetrafluoroethylene preform is extruded from the cavity between the die head 20 and the core die 22 to obtain a polytetrafluoroethylene multi-cavity air guide screen tube blank;

[0051] Step 5: If a barrel 6 of a different size needs to be replaced, the core rod 12 and the push rod 10 are moved axially backward so that the core mold 22, the core rod 12 and the push rod 10 are moved out of the barrel 6;

[0052] Step 6, select a suitable barrel 6, add the polytetrafluoroethylene preform into the barrel 6, repeat steps 2-4, and complete the production of the polytetrafluoroethylene multi-cavity gas-guiding screen tube blank.

[0053] Step 7: Sinter the polytetrafluoroethylene multi-cavity gas-conducting screen tube blank to form a medical polytetrafluoroethylene multi-cavity gas-conducting screen tube.

[0054] Based on the manufacturing device used in the manufacturing method of the above-mentioned medical polytetrafluoroethylene multi-lumen air guide screen tube, such as Figure 1-3 As shown, it includes a horizontal extruder structure and a sintering device 1, wherein the sintering device 1 is located near the outlet end of the horizontal extruder structure.

[0055] The horizontal extruder structure includes a working plane 19 , a turntable, multiple barrels, a push rod push-pull transmission component, and a core rod push-pull transmission component; the turntable, barrels, push rod push-pull transmission component, and core rod push-pull transmission component are all built on the working plane 19 .

[0056] like Figure 1-2 As shown, the right end stopper 2, the upper fixing plate 8 and the motor mounting plate 13 are fixedly connected to the working plane 19.

[0057] like Figure 1-4As shown, the turntable includes turntable 1 4 and turntable 2 7; the front end of the rotating load-bearing shaft 5 is connected to the right end stopper 2, and the rear end is connected to the upper fixed plate 8, the center hole of turntable 1 4 and the center hole of turntable 2 7 are both rotatably connected to the rotating load-bearing shaft 5, a plurality of barrels 6 pass through turntable 1 4 and turntable 2 7 and are connected to turntable 1 4 and turntable 2 7, and the plurality of barrels 6 are evenly spaced along the circumferential direction of turntable 1 4 and turntable 2 7.

[0058] like Figure 1-4 As shown, the push rod push-pull transmission component includes a push rod drive mechanism 16, a movable plate 11 and a push rod 10. The upper fixed plate 8 and the motor mounting plate 13 are connected by a light rod 9. The cross-sectional shape of the light rod 9 is circular and there are four of them. The movable plate 11 is slidably connected to the light rod 9, the push rod drive mechanism 16 is connected to the motor mounting plate 13, the rear end of the push rod drive mechanism 16 is connected to the working plane 19 through a support rod 18, the driving end of the push rod drive mechanism 16 is connected to the movable plate 11 and is used to push and pull the movable plate 11, the movable plate 11 is connected to the push rod 10, the push rod 10 passes through the through hole on the upper fixed plate 8 and the push rod 10 can slide in the through hole on the upper fixed plate 8; the push rod 10 is detachably connected with a piston 23, the piston 23 on the push rod 10 can extend into the barrel 6 of the multi-selection barrel device or can be separated from the barrel 6 of the multi-selection barrel device under the push and pull of the movable plate 11, and the piston 23 is in close sliding contact with the inner wall of the barrel 6.

[0059] like Figure 1-4 As shown, the core rod push-pull transmission component includes a core rod drive mechanism 17 and a core rod 12; the core rod drive mechanism 17 is connected to the motor mounting plate 13, the driving end of the core rod drive mechanism 17 is connected to the core rod 12 and is used to push and pull the core rod 12, the push rod 10 is sleeved with the core rod 12, that is, the push rod 10 is provided with an axial hole extending along the length direction of the push rod 10, the core rod 12 passes through the axial hole of the push rod 10 and the through hole on the piston 23, and the core rod 12 can slide in the axial hole of the push rod 10 and the through hole on the piston 23. The die head 20, the die head fixing ring 21 and the core mold 22 constitute the die head assembly, the die head 20 is detachably connected to the barrel 6 through the die head fixing ring 21, and the core mold 22 is detachably connected to the front end of the core rod 12.

[0060] The axes of the core rod 12, the push rod 10, the piston 23, and the core mold 22 are located on the same straight line. The cross sections of the core rod 12, the push rod 10, and the piston 23 are all circular. The axis of the inner hole of the die head 20 and the axis of the inner hole of the barrel 6 are located on the same straight line. The inner hole of the die head 20 and the inner hole of the barrel 6 are both through holes.

[0061] In this embodiment, the front end of the rotating load-bearing shaft 5 is connected to the right end stopper 2 through the load-bearing shaft fixing block 3, and the load-bearing shaft fixing block 3 and the right end stopper 2 are connected by bolts, and the rear end of the rotating load-bearing shaft 5 is connected to the upper fixed plate 8 through the load-bearing shaft fixing block 3, and the load-bearing shaft fixing block 3 and the upper fixed plate 8 are connected by bolts.

[0062] In this embodiment, the plurality of barrels 6 include a barrel with a diameter of 40 mm, a barrel with a diameter of 45 mm, and a barrel with a diameter of 50 mm, and the lengths are all 90 cm. The barrel 6 is used to add the polytetrafluoroethylene preform, and the outer circle of the polytetrafluoroethylene preform is matched with the inner wall of the barrel 6 with a small gap, so as to reduce the shaking of the polytetrafluoroethylene preform in the barrel 6, reduce eccentricity, and improve concentricity.

[0063] In this embodiment, there are two push rod driving mechanisms 16, and the driving ends of the two push rod driving mechanisms 16 are both inserted through the reserved through holes on the motor mounting plate 13 and are locked with the movable plate 11 by nuts. The driving ends of the push rod driving mechanisms 16 are slidingly connected to the reserved through holes on the motor mounting plate 13, the through hole in the middle of the movable plate 11 is threadedly connected to the push rod 10, and the push rod 10 is threadedly connected to the piston 23.

[0064] In this embodiment, there are two core rod driving mechanisms 17, and the driving ends of the two core rod driving mechanisms 17 are connected to the sliding block 15 by nuts after passing through the reserved through holes on the motor mounting plate 13, and the reserved through holes on the motor mounting plate 13 are connected to the driving ends of the core rod driving mechanisms 17 in a sliding manner. The core rod 12 is located in the axial hole of the push rod 10 and passes through the through hole in the middle of the movable plate 11 and the through hole in the middle of the motor mounting plate 13 in sequence, and is connected to the sliding block 15 through the core rod fixing block and bolts, and the core rod 12 is connected to the through hole in the middle of the motor mounting plate 13 in a sliding manner. The core rod 12 is supported inside the push rod 10 through the piston 23 and the through hole in the center of the motor mounting plate 13, and the axis of the core rod 12 and the axis of the push rod 10 can be located on the same straight line. Driven by the core rod driving mechanism 17, the core rod 12 can slide inside the push rod 10, inside the piston 23, and inside the through hole in the middle of the motor mounting plate 13. The core rod fixing block is connected to the sliding block 15 by bolts, and the core rod 12 is connected to the through hole on the piston 23 in a sliding and sealing manner.

[0065] In this embodiment, the core rod 12 is made of 304 stainless steel; the push rod driving mechanism 16 adopts electric cylinder 1, which is connected to the motor mounting plate 13 through the cylinder front flange 14 and bolts, and the electric cylinder 1 adopts a 5T motor; the core rod driving mechanism 17 adopts electric cylinder 2, which is connected to the motor mounting plate 13 through the cylinder front flange 14 and bolts, and the electric cylinder 2 adopts a 500kg motor.

[0066] In this embodiment, Figure 6As shown, the core mold 22 includes a threaded area 221, a conical area 222 and a plurality of core rods 223, the threaded area 221, the conical area 222 and the plurality of core rods 223 are fixedly connected in sequence, and the threaded area 221 is threadedly connected to the end hole on the core rod 12.

[0067] In this embodiment, the die head fixing ring 21 is connected to the end surface of the barrel 6 by bolts or screws, and the core mold 22 is located in the inner hole of the die head 20. Figure 5 As shown, the inner hole of the die head 20 includes a conical inner hole 201 and a cylindrical inner hole 202. The cylindrical inner hole 202 passes through one end of the die head 20 to form an outlet of the die head 20. The conical area 222 of the core mold 22 is located in the conical inner hole 201 of the die head 20, and the core rod 223 of the core mold 22 is located in the cylindrical inner hole 202.

[0068] Furthermore, in order to reduce the eccentricity of the blank in the cavity and improve the concentricity of the multi-cavity pipe, the horizontal extruder in the present invention is provided with a plurality of barrels 6 and die assemblies mounted on a turntable. One end of the die assembly is fixedly connected with the end hole on the barrel 6 by a die fixing ring 21 with a plurality of mounting holes through bolts to realize the connection between the die 20 and the barrel 6. Preferably, the die fixing ring 21 is provided with 4 through screw holes to reduce the number of times it is disassembled and ensure the concentricity of the die end. When in use, according to the needs, first select a suitable barrel 6, open the electric cylinder 1 in the push rod driving mechanism 16, the electric cylinder 1 pulls the push rod 10 through the movable plate 11, so that the push rod 10 is separated from the barrel 6, and the electric cylinder 1 is closed; open the electric cylinder 2 in the core rod driving mechanism 17, and the electric cylinder 2 pulls the core rod 12 to the rear end position of the corresponding electric cylinder 2 through the sliding block 15, so that the core rod 12 is separated from the barrel 6, and the electric cylinder 2 is closed. Manually rotate the turntable 1 4 and the turntable 2 7 to turn the selected barrel 6 to the other side. If one end of the selected barrel 6 has been connected to the die head 20 through the die head fixing ring 21 (if the die head 20 is not installed, one end of the barrel 6 is connected to the matching die head 20 through the die head fixing ring 21), a polytetrafluoroethylene preform with a small clearance matching the inner diameter of the barrel 6 is added to the inner hole at the other end of the corresponding barrel 6 (the feeding end of each barrel 6 is facing the direction of the push rod 10, and the end hole at the feeding end of the barrel 6 can be set as a hole with a guiding slope to facilitate the preform to enter the barrel 6 and also facilitate the push rod 10. The outer diameter of the polytetrafluoroethylene preform is matched with the inner diameter of the barrel 6 with a small clearance to reduce the shaking of the polytetrafluoroethylene preform in the barrel 6. A through hole slightly larger than the outer diameter of the core rod 12 and extending along its length is provided in the middle of the polytetrafluoroethylene preform to facilitate the insertion of the core rod 12. After the polytetrafluoroethylene preform is successfully loaded into the barrel 6, the turntable 1 4 and the turntable 2 7 are rotated in the opposite direction to make the barrel 6 containing the polytetrafluoroethylene preform coaxially aligned with the push rod 10 and the core rod 12 (the alignment method can be manual alignment or auxiliary alignment can be performed by an alignment tool). The electric cylinder 2 in the core rod driving mechanism 17 is turned on again, and the electric cylinder 2 pushes the core rod 12 toward the barrel 6 through the sliding block 15. After reaching the preset stroke, the electric cylinder 2 is turned off. At this time, the core rod 12 has penetrated the through hole in the middle of the polytetrafluoroethylene preform in the barrel 6, and the core mold 22 at the front end of the core rod 12 is located on the inner side of the die head 20, and the core rod 223 on the core mold 22 has been inserted into the cylindrical hole of the die head 20.At this time, the electric cylinder 1 in the push rod driving mechanism 16 is turned on again. The electric cylinder 1 pushes the push rod 10 toward the barrel 6, and the piston 23 of the push rod 10 enters the barrel 6. The outer circle of the piston 23 slides in a sealed manner with the inner wall of the barrel 6. At this time, the axis of the piston 23 is aligned with the axis of the barrel 6. Since the axes of the piston 23, the core rod 12, the push rod 10, and the core mold 22 are located on the same straight line, the axis of the inner hole of the die head 20 and the axis of the inner hole of the barrel 6 are located on the same straight line, therefore, the axis of the core mold 22 and the axis of the die head 20 are located on the same straight line, and the core mold 22 is located at the center position of the die head 20, ensuring the concentricity of the polytetrafluoroethylene preform and the core mold 22, the piston 23 of the push rod 10 pushes the polytetrafluoroethylene preform in the barrel 6, the polytetrafluoroethylene preform enters the cavity between the die head 20 and the core mold 22, and then extrudes the medical multi-lumen tubing blank from the outlet of the die head 20, and then is sintered by the sintering device to finally form a product.

[0069] The turntable 1 4 and the turntable 2 7 are provided with circular perforations corresponding to the three barrels 6 and the rotating bearing shaft 5. The rotating bearing shaft 5 is located at the center of the turntable 1 4 and the turntable 2 7. The three barrels 6 are evenly distributed at an angle of 120° along the circumference of the turntable 1 4 and the turntable 2 7. At the same time, the three barrels 6 and the rotating bearing shaft 5 are all detachably connected to the turntable 1 4. The three barrels 6 and the rotating bearing shaft 5 are all detachably connected to the turntable 2 7, and the connection method can be bolt, key connection, pin connection, etc.

[0070] The movable plate 11 is an I-shaped hexahedron with a vertically symmetrical structure, and is provided with seven holes. Both the upper and lower parts have through holes that can ensure that the polished rod 9 can pass through.

[0071] In order to ensure that the 500kg motor of the electric cylinder 2 can smoothly push and pull the core rod 12 so that the two form a unified connection structure, a sliding block 15 is set at the rear end of the core rod 12 as a connection component. During use, turning on the 500kg motor can realize the horizontal movement of the core rod 12 in a direction parallel to its axis.

[0072] The electric cylinder 1 and the electric cylinder 2 are sealedly connected to the motor mounting plate 13 via a hexahedral cylinder front flange 14. Preferably, the hexahedral cylinder front flange 14 complies with the 135 cylinder front flange standard.

[0073] The 5T motor of the electric cylinder 1 is turned on to provide axial pushing force, which can push the movable plate 11 forward to move horizontally, so that the push rod 10 moves forward to extrude the polytetrafluoroethylene preform in the material cavity of the barrel 6 to prepare a multi-cavity tube blank.

[0074] The threaded area 221 in the core mold 22 is used to connect with the threaded hole at the end of the core rod 12. The conical area 222 is a necessary area for maintaining the shape of the pipe, and has a certain length and cone angle. The angle of the conical part of the conical area 222 is preferably 20°-60°, so as to guide the extruded polytetrafluoroethylene blank to flow in a certain direction. The lower part of the conical area 222 is fixedly connected with the core rod 223. The core rod 223 is a long straight pipe with an exhaust hole. The length of the core rod 223 is preferably 20-30% of the total length of the core mold 22. The gap between each core rod 223 is preferably 0.5-1mm. The number of core rods 223 is set to an even number, and the even number of core rods 223 is symmetrically distributed around the axis, thereby forming a symmetrical multi-cavity structure. In this embodiment, the threaded area 221 in the core mold 22 of different sizes can be threadedly connected with the threaded hole at the end of the core rod 12, and the outer diameter of the large diameter end of the conical area 222 is consistent with the outer diameter of the core rod 12. The core rod 12 is a long cylindrical rod.

[0075] Specifically, the mandrel 223 is provided with 12 pieces, and the following can be prepared: Figure 7 The medical twelve-lumen gas guide tube shown.

[0076] The medical multi-cavity gas-guiding screen tube prepared by the preparation method of the present invention has at least the following advantages:

[0077] The multi-cavity tube provided by the embodiment of the present invention can be applied to at least the field of gas-guiding screen tubes. Because a horizontal extruder with a device for selecting multiple barrels is used, materials can be added from three barrels 6 respectively to reduce disassembly. The outer diameter of the preform and the inner diameter of the barrel 6 are matched with a small gap to prevent the preform from shaking in the barrel 6, improve the concentricity of the preform, and prevent eccentricity caused by improper installation of the preform and the core mold 22. One end of the die head 20 is fixedly connected to the end of the barrel 6 by a die head fixing ring 21 with multiple through screw holes, and can be repeatedly used for many times after one installation. The multi-cavity screen tube finally prepared has good dimensional stability, uniform wall thickness, good concentricity, can be industrialized on a large scale, is easy to operate, saves time and effort, and has high production efficiency. In actual use, the die head assembly of appropriate size can also be replaced according to requirements, and the disassembly and assembly of the die head assembly is also simple and convenient. In addition, for barrels 6 with different inner diameters, the piston 23 on the push rod 10 can also be replaced (all replaced pistons 23 have slightly different outer diameters, the same inner diameters and the same size of the threaded end connected to the push rod, to achieve matching with the same core rod 12 and the same push rod 10), ensuring that the piston 23 can be in sealed sliding contact with the inner wall of the barrel 6. In the overall structure of the present invention, some structures are connected by threads, bolts or nuts, etc., and installation and disassembly are simple and convenient. The molding method of the polytetrafluoroethylene preform is not within the scope of protection of the present invention.

[0078] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be the protection scope of the claims.

Claims

1. A method for manufacturing a medical polytetrafluoroethylene multi-cavity gas-guiding screen tube, It is characterized in that The following steps are involved: Step 1: a plurality of barrels (6) are connected at intervals in the circumferential direction of a rotating disk rotating around the center of the rotating disk; a polytetrafluoroethylene preform is added into the barrel (6); and a die head (20) is connected to the front end of the barrel (6); Step 2: Rotate the turntable until a barrel (6) containing a polytetrafluoroethylene preform is rotated to a position coaxial with the core rod (12); Step 3: The front end of the core rod (12) is connected to the core mold (22); the core rod (12) is pushed axially forward, and the core mold (22) enters the rear end of the barrel (6) and passes through the inner hole of the polytetrafluoroethylene preform until the core mold (22) is located inside the die head (20), and the core rod (12) stops moving; Step 4: The push rod (10) coaxial with the core rod (12) and sleeved on the outer circumference of the core rod (12) moves axially forward, the front end of the push rod (10) enters the rear end of the barrel (6) and applies pressure to the polytetrafluoroethylene preform inside the barrel (6), and the polytetrafluoroethylene preform is extruded from the cavity between the die head (20) and the core die (22), thereby obtaining a polytetrafluoroethylene multi-cavity air guide screen tube blank; Step 5: Sintering the polytetrafluoroethylene multi-cavity gas-conducting screen tube blank to form a medical polytetrafluoroethylene multi-cavity gas-conducting screen tube.

2. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 1, It is characterized in that After step 4 we have: Step 41: the core rod (12) and the push rod (10) are moved axially backward, so that the core mold (22), the core rod (12) and the push rod (10) are moved out of the barrel (6); Step 42: Repeat steps 2-4 to complete the production of the polytetrafluoroethylene multi-cavity gas-conducting screen tube blank.

3. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 1, It is characterized in that A push rod push-pull transmission component for driving the push rod (10) to move axially and a core rod push-pull transmission component for driving the core rod (12) to move axially are installed on the working plane (19), and the center of the turntable is rotatably connected above the working plane (19).

4. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 3, It is characterized in that The working plane (19) is connected with a right end stopper (2), an upper fixing plate (8) and a motor mounting plate (13); The turntable comprises a turntable 1 (4) and a turntable 2 (7); the center holes of the turntable 1 (4) and the turntable 2 (7) are both rotatably connected to a rotating load-bearing shaft (5); the two ends of the rotating load-bearing shaft (5) are respectively connected to a right end stopper (2) and an upper fixed plate (8); a plurality of barrels (6) penetrate the turntable 1 (4) and the turntable 2 (7) and are connected to the turntable 1 (4) and the turntable 2 (7); the plurality of barrels (6) are evenly spaced and arranged along the circumferential direction of the turntable 1 (4) and the turntable 2 (7); The push rod push-pull transmission component comprises a push rod driving mechanism (16), a movable plate (11) and a push rod (10); the upper fixed plate (8) and the motor mounting plate (13) are connected via a light rod (9); the movable plate (11) and the light rod (9) are slidably connected; the push rod driving mechanism (16) is connected to the motor mounting plate (13); the driving end of the push rod driving mechanism (16) is connected to the movable plate (11) and is used to push and pull the movable plate (11); the movable plate (11) is connected to the push rod (10); the push rod (10) passes through a through hole on the upper fixed plate (8) and the push rod (10) can slide in the through hole on the upper fixed plate (8); a piston (23) is detachably connected to the front end of the push rod (10); the piston (23) on the push rod (10) can extend into the barrel (6) under the push of the movable plate (11); the piston (23) is in sliding contact with the inner wall of the barrel (6); The core rod push-pull transmission component comprises a core rod driving mechanism (17) and a core rod (12); the core rod driving mechanism (17) is connected to the motor mounting plate (13); the driving end of the core rod driving mechanism (17) is connected to the core rod (12) and is used to push and pull the core rod (12); an axial hole extending along the length direction of the push rod (10) is provided on the push rod (10); the core rod (12) passes through the axial hole of the push rod (10) and the through hole on the piston (23); and the core rod (12) can slide in the axial hole of the push rod (10) and the through hole on the piston (23); the die head (20) is detachably connected to the barrel (6) through the die head fixing ring (21); and the core mold (22) is detachably connected to the core rod (12); The axes of the core rod (12), the push rod (10), the piston (23) and the core mold (22) are located on the same straight line, and the axes of the inner hole in the die head (20) and the inner hole in the barrel (6) are located on the same straight line.

5. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 1, Features: The plurality of barrels (6) include a barrel with a diameter of 40 mm, a barrel with a diameter of 45 mm and a barrel with a diameter of 50 mm, and are all 90 cm long; the plurality of barrels (6) are all used for adding polytetrafluoroethylene preforms, and the outer circle of the polytetrafluoroethylene preform is gap-matched with the inner wall of the barrel (6).

6. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 4, Features: There are two push rod driving mechanisms (16), and the driving ends of the two push rod driving mechanisms (16) are connected to the movable plate (11) after passing through the reserved through holes on the motor mounting plate (13). The movable plate (11) is threadedly connected to one end of the push rod (10), and the other end of the push rod (10) is threadedly connected to the piston (23).

7. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 4, Features: There are two core rod driving mechanisms (17), the driving ends of the two core rod driving mechanisms (17) are connected to the sliding block (15) after passing through the reserved through holes on the motor mounting plate (13), one end of the core rod (12) is connected to the middle of the sliding block (15) after passing through the through hole in the middle of the motor mounting plate (13), the core rod (12) is slidably connected to the through hole in the middle of the motor mounting plate (13), and the core rod (12) is slidably and sealingly connected to the through hole on the piston (23).

8. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 7, Features: The core rod (12) is made of 304 stainless steel; the push rod driving mechanism (16) is made of electric cylinder 1, which is connected to the motor mounting plate (13) through a cylinder front flange (14) and bolts; the core rod driving mechanism (17) is made of electric cylinder 2, which is connected to the motor mounting plate (13) through a cylinder front flange (14) and bolts.

9. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 1, Features: The core mold (22) comprises a threaded area (221), a conical area (222) and a plurality of core rods (223); the threaded area (221), the conical area (222) and the plurality of core rods (223) are fixedly connected in sequence; the threaded area (221) is threadedly connected to an end hole on the core rod (12).

10. The method for manufacturing the medical polytetrafluoroethylene multi-cavity gas-guiding screen tube according to claim 9, Features: The number of the core rods (223) is an even number, the length of the core rods (223) is 20-30% of the total length of the core mold (22), and the gap between each core rod (223) is 0.5-1 mm.

Images