Forming mold of heat-resistant PLA (polylactic acid) catheter

Abstract

The invention discloses a forming mold of a heat-resistant PLA catheter, and particularly relates to the technical field of PLA catheter formation.The forming mold comprises a mold frame, a mouth mold, a pressing ring, a core rod and an adjusting part, a plurality of sliding grooves are evenly formed in the core rod in the circumferential direction, a first positioning piece is arranged in each sliding groove, and a rolling piece is arranged at the end, away from the central axis of the core rod, of each first positioning piece; the adjusting part comprises a plurality of pressure measuring grooves evenly formed in the inner portion of the core rod in the circumferential direction, pressure measuring pieces are arranged in the pressure measuring grooves, and the pressure measuring pieces can judge the coaxiality of the core rod and the mouth mold by detecting the pressure of the rolling piece. Meanwhile, when it is detected that the mouth mold and the core rod are not coaxial, the relative positions of the mouth mold and the core rod are adjusted by adjusting the second positioning piece, and the problem that due to the fact that the positions of the mouth mold and the core rod deviate, the mouth mold and the core rod are not coaxial, and the wall thickness of the machined PLA guide pipe is inconsistent is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of PLA catheter forming, and more specifically, to a forming mold for a heat-resistant PLA catheter. Background Art

[0002] During the production of a PLA catheter, after PLA particles are heated and melted in an extruder, they enter a forming mold at a certain pressure and speed to form a tubular PLA melt, which becomes a single catheter after cooling and shaping. Since the PLA material changes from a solid state to a molten state and then enters the forming mold for shaping, a certain temperature still needs to be maintained during the forming process.

[0003] However, since the PLA material flows linearly during the forming process, and the heating device is usually on the surface of the die head and the mold base, the PLA material is prone to uneven heating. During the long-term use of the forming mold, each time the die head and the mandrel are assembled, the contact surface between the die head and the mandrel will be worn due to the fitting clearance. As the use time increases, the fitting clearance will become larger and larger. If the positions of the die head and the mandrel are offset, resulting in non-concentricity between the die head and the mandrel, it will cause inconsistent wall thickness of the processed PLA catheter. Therefore, the present invention proposes a forming mold for a heat-resistant PLA catheter to solve the above problems. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a forming mold for a heat-resistant PLA catheter to solve the problems raised in the above background art.

[0005] To achieve the above object, the present invention provides the following technical solution: A forming mold for a heat-resistant PLA catheter, comprising: a mold base, a die head, a compression ring, a mandrel, and an adjustment part. A plurality of sliding grooves are circumferentially and uniformly opened inside the mandrel. A first positioning member is arranged inside each sliding groove. A rolling member is arranged at one end of each first positioning member away from the central axis of the mandrel. When the mandrel and the die head are assembled, the rolling member can reduce the friction during the assembly of the mandrel and the die head through rolling; the adjustment part includes a plurality of pressure measuring grooves circumferentially and uniformly opened inside the mandrel. A pressure measuring member is arranged inside the pressure measuring groove. The pressure measuring member can judge the coaxiality of the mandrel and the die head by detecting the pressure of the rolling member.

[0006] Preferably, the adjustment part further includes an adjustment groove opened inside the mandrel. A fixing rod is fixedly connected to the inner wall of the adjustment groove. One end of the fixing rod is fixedly connected with a fixing member. An adjusting member is movably connected to the outer wall of the fixing member. When the pressures inside the pressure measuring grooves are equal, the adjusting member is coaxial with the mandrel.

[0007] Preferably, one end of the first positioning member away from the rolling member is fixedly connected to a first piston rod. One end of the first piston rod away from the first positioning member is fixedly connected to a first piston plate. The outer wall of the first piston plate is slidably connected to a first piston cylinder. A first elastic member is arranged inside the first piston cylinder. One end of the first elastic member is fixedly connected to one end of the first piston cylinder, and the other end of the first elastic member is fixedly connected to one end of the first piston plate away from the first piston rod.

[0008] Preferably, a plurality of sealing grooves are evenly formed in the circumferential direction inside the mandrel. A sealing member is slidably connected inside the sealing groove. A second elastic member is arranged inside the sealing groove. One end of the second elastic member is fixedly connected to the inner wall of the sealing groove, and the other end of the second elastic member is fixedly connected to the sealing member. One end of the sealing member away from the second elastic member is fixedly connected to a push rod. One end of the push rod away from the sealing member extends into the adjusting groove and contacts one end of the adjusting member.

[0009] Preferably, the pressure measuring member is slidably connected to the pressure measuring groove. One end of the pressure measuring member penetrates through the pressure measuring groove and contacts one end of the adjusting member away from the push rod. A first pipeline is arranged inside the mandrel. The pressure measuring groove is communicated with the first piston cylinder through the first pipeline.

[0010] Preferably, a plurality of second positioning members are evenly arranged on the circumferential side of one end of the die holder. The second positioning members are connected to the die holder by bolts. A positioning column is slidably connected inside the second positioning member. One end of the positioning column contacts the outer wall of the die orifice. A third elastic member is arranged inside the second positioning member. One end of the third elastic member is fixedly connected to the second positioning member, and the other end of the third elastic member is fixedly connected to one end of the positioning column away from the die orifice.

[0011] Preferably, an air groove is formed inside the mandrel. A second pipeline is arranged inside the mandrel. The air groove is communicated with the sealing groove through the second pipeline. An air vent hole is formed inside the sealing member. The sealing member can slide to make the air vent hole communicate with the air groove. An air inlet hole is formed at one end of the second positioning member away from the outer wall of the die holder. The second pipeline is connected to the air inlet hole through a flexible hose.

[0012] Preferably, the mandrel further includes a bracket movably connected to the die holder. One end of the bracket close to the die holder is fixedly connected to a diverter. The diverter is of a conical structure. The inner cavity of the die holder is of a conical structure. The inner cavity of the die holder and the diverter cooperate to form a flow channel.

[0013] Preferably, a plurality of diversion holes are arranged inside the bracket. The diversion holes correspond to the flow channel. One end of the bracket away from the die holder is fixedly connected to a forming member. One end of the forming member close to the bracket is of a conical structure, and one end of the forming member away from the bracket is of a cylindrical structure.

[0014] Preferably, the inner cavity of the die is matched with the formed part to form a flow channel, and the pressing ring and the die holder are fixedly connected by bolts.

[0015] Technical effects and advantages of the present invention:

[0016] 1. In the present invention, the mandrel first divides the PLA material and then forms it, increasing the contact area and contact time between the PLA material and the die flow channel wall, which is beneficial to heat transfer and ensures that the material is formed at a suitable temperature.

[0017] 2. In the present invention, by making the rolling element contact the inner wall of the die, the contact area between the inner wall of the die and the mandrel is reduced, and at the same time, the sliding friction during the assembly of the inner wall of the die and the mandrel is changed into rolling friction, thereby reducing the wear during the assembly of the die and the mandrel and increasing the service life of the die.

[0018] 3. In the present invention, the moving distance of the rolling element is detected by multiple pressure measuring elements to judge the coaxiality of the die and the mandrel. At the same time, when it is detected that the die and the mandrel are not coaxial, the relative positions of the die and the mandrel are adjusted by adjusting the second positioning element, preventing the problem that the wall thickness of the PLA catheter processed is inconsistent due to the offset of the positions of the die and the mandrel, resulting in non - coaxiality of the die and the mandrel. Description of the drawings

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 It is an exploded schematic diagram of the overall structure of the present invention.

[0021] Figure 3 It is a sectional view of the overall structure of the present invention.

[0022] Figure 4 For the present invention Figure 3 Enlarged view of the structure of part A.

[0023] Figure 5 For the present invention Figure 3 Enlarged view of the structure of part B.

[0024] Figure 6 It is a sectional view of the mandrel structure of the present invention.

[0025] Figure 7 It is a sectional view of the second positioning element structure of the present invention.

[0026] Figure 8 It is a schematic diagram of the first positioning element structure of the present invention.

[0027] The reference numerals are: 1, die set; 2, die head; 3, pressing ring; 4, mandrel; 41, chute; 42, first positioning member; 421, first piston rod; 422, first piston plate; 423, first piston cylinder; 424, first elastic member; 43, rolling member; 44, bracket; 441, shunt hole; 45, forming member; 5, adjusting portion; 51, pressure measuring groove; 511, first pipeline; 52, pressure measuring member; 53, adjusting groove; 531, fixing rod; 532, fixing member; 54, adjusting member; 55, sealing groove; 551, second elastic member; 552, second pipeline; 56, sealing member; 561, push rod; 562, ventilation hole; 57, second positioning member; 571, positioning column; 572, third elastic member; 573, air inlet hole; 58, air groove. Detailed implementation manners

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Embodiment 1

[0030] During the actual production process, due to the phenomenon that the PLA material is unevenly heated during the forming process, this embodiment is specifically invented to solve the above problems.

[0031] Please refer to Figures 1 to 8 As shown, a forming mold for a heat-resistant PLA catheter according to an embodiment of the present invention includes a die set 1, a die head 2, a pressing ring 3, a mandrel 4, and an adjusting portion 5; a plurality of chutes 41 are circumferentially and uniformly formed inside the mandrel 4, and a first positioning member 42 is disposed inside each chute 41. A rolling member 43 is disposed at one end of each first positioning member 42 away from the central axis of the mandrel 4. When the mandrel 4 is assembled with the die head 2, the rolling member 43 can reduce the friction during the assembly of the mandrel 4 and the die head 2 by rolling; in combination with Figure 3 and Figure 4 As shown, the adjusting portion 5 includes a plurality of pressure measuring grooves 51 circumferentially and uniformly formed inside the mandrel 4, and a pressure measuring member 52 is disposed inside the pressure measuring groove 51. The pressure measuring member 52 can judge the coaxiality of the mandrel 4 and the die head 2 by detecting the pressure of the rolling member 43.

[0032] Please refer to Figure 3 and Figure 4As shown, the adjusting part 5 further includes an adjusting groove 53 formed inside the mandrel 4. A fixing rod 531 is fixedly connected to the inner wall of the adjusting groove 53. One end of the fixing rod 531 is fixedly connected to a fixing part 532. An adjusting part 54 is movably connected to the outer wall of the fixing part 532. When the pressures inside the pressure measuring grooves 51 are equal, the adjusting part 54 is coaxial with the mandrel 4.

[0033] Please refer to Figure 5 and Figure 8 As shown, one end of the first positioning part 42 away from the rolling part 43 is fixedly connected to a first piston rod 421. One end of the first piston rod 421 away from the first positioning part 42 is fixedly connected to a first piston plate 422. The outer wall of the first piston plate 422 is slidably connected to a first piston cylinder 423. A first elastic part 424 is arranged inside the first piston cylinder 423. One end of the first elastic part 424 is fixedly connected to one end of the first piston cylinder 423. The other end of the first elastic part 424 is fixedly connected to the end of the first piston plate 422 away from the first piston rod 421.

[0034] Please refer to Figure 4 and Figure 6 As shown, a plurality of sealing grooves 55 are evenly formed in the circumferential direction inside the mandrel 4. A sealing part 56 is slidably connected inside the sealing grooves 55. A second elastic part 551 is arranged inside the sealing grooves 55. One end of the second elastic part 551 is fixedly connected to the inner wall of the sealing grooves 55. The other end of the second elastic part 551 is fixedly connected to the sealing part 56. One end of the sealing part 56 away from the second elastic part 551 is fixedly connected to a push rod 561. One end of the push rod 561 away from the sealing part 56 extends into the adjusting groove 53 and contacts one end of the adjusting part 54. The pressure measuring part 52 is slidably connected to the pressure measuring groove 51. One end of the pressure measuring part 52 penetrates through the pressure measuring groove 51 and contacts the end of the adjusting part 54 away from the push rod 561. A first pipeline 511 is arranged inside the mandrel 4. The pressure measuring groove 51 is communicated with the first piston cylinder 423 through the first pipeline 511.

[0035] Please refer to Figure 3 and Figure 7 As shown, a plurality of second positioning parts 57 are evenly arranged on the circumferential side of one end of the mold base 1. The second positioning parts 57 are connected to the mold base 1 by bolts. A positioning column 571 is slidably connected inside the second positioning parts 57. One end of the positioning column 571 contacts the outer wall of the die head 2. A third elastic part 572 is arranged inside the second positioning parts 57. One end of the third elastic part 572 is fixedly connected to the second positioning parts 57. The other end of the third elastic part 572 is fixedly connected to the end of the positioning column 571 away from the die head 2.

[0036] Please refer to Figure 4As shown, an air groove 58 is formed inside the mandrel 4, compressed gas is provided inside the air groove 58, a second pipeline 552 is provided inside the mandrel 4, and the air groove 58 communicates with the sealing groove 55 through the second pipeline 552. An air vent hole 562 is formed inside the seal 56, and the seal 56 can slide to communicate the air vent hole 562 with the air groove 58. An air inlet hole 573 is formed at one end of the second positioning member 57 away from the outer wall of the mold base 1, and the second pipeline 552 is connected to the air inlet hole 573 through a flexible hose. The seal 56 can slide to communicate the air vent hole 562 with the second pipeline 552.

[0037] Please refer to Figure 2 As shown, the mandrel 4 further includes a bracket 44 movably connected to the mold base 1. A diverter is fixedly connected to one end of the bracket 44 close to the mold base 1. The diverter is of a conical structure, and the inner cavity of the mold base 1 is of a conical structure. The inner cavity of the mold base 1 and the diverter cooperate to form a flow channel.

[0038] Please refer to Figure 2 As shown, a plurality of diversion holes 441 are provided inside the bracket 44. The diversion holes 441 correspond to the flow channel. A forming member 45 is fixedly connected to one end of the bracket 44 away from the mold base 1. One end of the forming member 45 close to the bracket 44 is of a conical structure, and one end of the forming member 45 away from the bracket 44 is of a cylindrical structure. The inner cavity of the die head 2 cooperates with the forming member 45 to form a flow channel. The flow area of the flow channel between the die head 2 and the forming member 45 gradually decreases. The pressure ring 3 is fixedly connected to the mold base 1 through bolts, and a feed port is provided on the mold base 1.

[0039] During use, when the PLA material enters the inner cavity of the mold base 1 continuously in a fluid state, the fluid is diverted by the diverter at this time. The fluid is diverted by the diverter, so that the fluid contacts the inner wall of the mold base 1. As the fluid continuously enters, the fluid in the inner cavity of the mold base 1 continuously increases and then enters between the die head 2 and the forming member 45 of the mandrel 4 through the diversion holes 441 of the bracket 44. Since the forming member 45 is also of a conical structure and the flow channel between the forming member 45 and the inner cavity of the die head 2 gradually decreases, the flow resistance of the fluid increases, and the welding cracks generated after the fluid passes through the diversion port and then merges. When the fluid passes through the cylindrical structure of the forming member 45, an internally hollow cylindrical conduit is formed through the cooperation with the die head 2. The mandrel 4 first diverts and then forms the PLA material, increasing the contact area and contact time between the PLA material and the wall of the mold flow channel, facilitating heat transfer, and ensuring that the material is formed at a suitable temperature.

[0040] Embodiment 2

[0041] It is found during actual use that during the long-term use of the forming mold, each time the die head 2 and the mandrel 4 are assembled, the contact surface between the die head 2 and the mandrel 4 will be worn due to the fitting clearance, and further improvements are made on the basis of the above embodiment.

[0042] During use, in the process of assembling the forming die, first install the mandrel 4 inside the die holder 1, and then sleeved the die orifice 2 outside the mandrel 4. When the die orifice 2 is assembled with the mandrel 4, the inner wall of the die orifice 2 contacts the rolling element 43, so that the inner wall of the die orifice 2 presses the rolling element 43, causing the rolling element 43 to move towards the central axis direction of the mandrel 4 and press the first positioning member 42. By the first positioning member 42 moving towards the central axis direction of the mandrel 4, the first piston rod 421 drives the first piston plate 422 to move towards the central axis direction of the mandrel 4, so that the first elastic member 424 inside the first piston cylinder 423 is compressed. By the rolling element 43 contacting the die orifice 2, the contact area between the mandrel 4 and the die orifice 2 is reduced, and at the same time, the sliding friction during the installation of the die orifice 2 and the mandrel 4 is changed into rolling friction, thereby reducing the friction caused during the assembly of the die orifice 2 and the mandrel 4 and increasing the service life of the forming die.

[0043] Embodiment 3

[0044] It is found during actual use that with long-term use, the fit clearance will become larger and larger. If the positions of the die orifice 2 and the mandrel 4 are offset, resulting in the non-concentricity of the die orifice 2 and the mandrel 4, it will cause the wall thickness of the PLA catheter processed to be inconsistent. Further improvements are made on the basis of the above embodiments.

[0045] During use, in the process of assembling the die 2 and the mandrel 4, when the inner wall of the die 2 comes into contact with the rolling elements 43, the inner wall of the die 2 squeezes the multiple rolling elements 43, causing the multiple rolling elements 43 to move towards the central axis direction of the mandrel 4. As a result, the corresponding first piston plate 422 slides inside the first piston cylinder 423, enabling the gas inside the first piston cylinder 423 to enter the corresponding pressure measuring groove 51. Then, the pressure measuring member 52 slides inside the pressure measuring groove 51 and squeezes the adjusting member 54. When the die 2 and the mandrel 4 are coaxial, at this time, the degree of squeezing of the rolling elements 43 by the inner wall of the die 2 is the same, so that the moving distances of the multiple rolling elements 43 are the same, and the pressure of the pressure measuring member 52 squeezing the adjusting member 54 is the same, making the adjusting member 54 coaxial with the mandrel 4. When the die 2 and the mandrel 4 are not coaxial, at this time, the die 2 is eccentric, so that the degree of squeezing of the rolling elements 43 by the inner wall of the die 2 is inconsistent, resulting in inconsistent moving distances of the multiple rolling elements 43, and inconsistent moving distances of the first piston plate 422, making the pressures inside the multiple pressure measuring grooves 51 uneven. When the pressure received by any pressure measuring member 52 is greater than that received by other pressure measuring members 52, the pressure of this pressure measuring member 52 squeezing the adjusting member 54 is relatively large, and the pressures of other pressure measuring members 52 squeezing the adjusting member 54 are relatively small. As a result, the side of the adjusting member 54 receiving a larger pressure deviates away from the pressure measuring groove 51, and at the same time, it squeezes the push rod 561 to drive the seal 56 to move. At this time, the vent hole 562 is not in communication with the gas groove 58 and the second pipe 552. The side of the adjusting member 54 receiving a smaller pressure deviates towards the pressure measuring groove 51, and at the same time, the second elastic member 551 relaxes, causing the seal 56 to move towards the pressure measuring groove 51 in the seal groove 55, so that the vent hole 562 is in communication with the gas groove 58 and the second pipe 552. Then, the compressed gas inside the gas groove 58 enters the corresponding second positioning member 57, increasing the pressure inside the corresponding second positioning member 57 to squeeze the die 2, thereby adjusting the relative position of the die 2 and the mandrel 4. When the degree of squeezing of the rolling elements 43 by the die 2 is adjusted to be the same, at this time, the pressure measuring member 52 receives the same pressure, and the adjusting member 54 no longer deviates. At this time, the die 2 and the mandrel 4 are coaxial.

[0046] As described above, only the preferred specific embodiments of the present invention are provided, 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, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, should be covered within the protection scope of the present invention.

Claims

1. A forming die for a heat-resistant PLA catheter, comprising a die carrier, a die orifice and a pressing ring, characterized in that, It further includes: A mandrel, wherein a plurality of sliding grooves are evenly formed in the circumferential direction inside the mandrel, a first positioning member is arranged inside each sliding groove, and a rolling member is arranged at one end of each first positioning member away from the central axis of the mandrel. When the mandrel is assembled with the die, the rolling member can reduce the friction during the assembly of the mandrel and the die by rolling; An adjusting part, the adjusting part includes a plurality of pressure measuring grooves evenly formed in the circumferential direction inside the mandrel, a pressure measuring member is arranged inside the pressure measuring groove, and the pressure measuring member can judge the coaxiality of the mandrel and the die by detecting the pressure of the rolling member.

2. The molding die of the heat-resistant PLA catheter according to claim 1, characterized in that: The adjusting part further includes an adjusting groove formed inside the mandrel, a fixing rod is fixedly connected to the inner wall of the adjusting groove, a fixing member is fixedly connected to one end of the fixing rod, and an adjusting member is movably connected to the outer wall of the fixing member. When the pressure inside the pressure measuring groove is equal, the adjusting member is coaxial with the mandrel.

3. The molding die of the heat-resistant PLA catheter according to claim 2, characterized in that: One end of the first positioning member away from the rolling member is fixedly connected with a first piston rod, one end of the first piston rod away from the first positioning member is fixedly connected with a first piston plate, the outer wall of the first piston plate is slidably connected with a first piston cylinder, a first elastic member is arranged inside the first piston cylinder, one end of the first elastic member is fixedly connected with one end of the first piston cylinder, and the other end of the first elastic member is fixedly connected with one end of the first piston plate away from the first piston rod.

4. The molding die of the heat-resistant PLA catheter according to claim 3, characterized in that: A plurality of sealing grooves are evenly formed in the circumferential direction inside the mandrel, a sealing member is slidably connected inside the sealing groove, a second elastic member is arranged inside the sealing groove, one end of the second elastic member is fixedly connected with the inner wall of the sealing groove, the other end of the second elastic member is fixedly connected with the sealing member, a push rod is fixedly connected to one end of the sealing member away from the second elastic member, and one end of the push rod away from the sealing member extends into the adjusting groove and contacts one end of the adjusting member.

5. The molding die of the heat-resistant PLA catheter according to claim 4, characterized in that: The pressure measuring member is slidably connected with the pressure measuring groove, one end of the pressure measuring member penetrates through the pressure measuring groove and contacts one end of the adjusting member away from the push rod, a first pipeline is arranged inside the mandrel, and the pressure measuring groove is communicated with the first piston cylinder through the first pipeline.

6. The molding die for the heat-resistant PLA catheter according to claim 5, characterized in that: A plurality of second positioning members are evenly arranged on the circumferential side of one end of the mold base, the second positioning members are connected to the mold base by bolts, a positioning column is slidably connected inside the second positioning members, one end of the positioning column contacts the outer wall of the die, a third elastic member is arranged inside the second positioning members, one end of the third elastic member is fixedly connected with the second positioning members, and the other end of the third elastic member is fixedly connected with one end of the positioning column away from the die.

7. The molding die for the heat-resistant PLA conduit according to claim 6, wherein: An air groove is formed inside the mandrel, a second pipeline is arranged inside the mandrel, the air groove is communicated with the sealing groove through the second pipeline, a ventilation hole is formed inside the sealing member, the sealing member can slide to make the ventilation hole communicate with the air groove, an air inlet hole is formed at one end of the second positioning member away from the outer wall of the mold base, and the second pipeline is connected with the air inlet hole through a flexible pipe.

8. The molding die for the heat-resistant PLA catheter according to claim 7, characterized in that: The mandrel further includes a bracket movably connected with the mold base, a diverter is fixedly connected to one end of the bracket close to the mold base, the diverter is of a conical structure, the inner cavity of the mold base is of a conical structure, and the inner cavity of the mold base and the diverter cooperate to form a flow channel.

9. The forming mold of a heat-resistant PLA catheter according to claim 8, characterized in that: The interior of the bracket is provided with a plurality of shunt holes, which correspond to the flow channels. One end of the bracket far from the mold base is fixedly connected with a forming part. One end of the forming part close to the bracket is a conical structure, and one end of the forming part far from the bracket is a cylindrical structure.

10. The molding die of the heat-resistant PLA catheter according to claim 9, characterized in that: The inner cavity of the die orifice cooperates with the forming part to form a flow channel, and the pressure ring is fixedly connected with the mold base through bolts.

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