Method for stretching a variable-diameter plastic tube and stretch-forming machine

Abstract

The present application relates to a kind of variable-diameter plastic pipe stretching method and stretch forming machine, it is related to the field of plastic pipe stretching variable-diameter technology, it includes steps S1: obtaining raw material size and forming size;Step S2: determining stretching scheme based on raw material size and forming size and executing stretching scheme;Step S3: determining inspection aperture gauge based on forming size;Step S4: determining inspection scheme based on inspection aperture gauge;Step S5: after executing stretching scheme, execute inspection scheme and obtain inspection image;Step S6: based on the analysis of the preset guide tube feature to inspection image to obtain large diameter area;Step S7: when large diameter area exists, based on large diameter area updates raw material size and repeats execution step S2 to step S6 until large diameter area does not exist;Step S8: when large diameter area does not exist, output stretching completion signal.The present application has automatic inspection and calibration, without human operation, improve the qualified rate and the effect of automation of variable-diameter plastic pipe stretching.

Description

Technical Field

[0001] This invention relates to the field of plastic pipe stretching and diameter reduction technology, and in particular to a stretching method and stretching forming machine for a plastic pipe with diameter reduction. Background Technology

[0002] The distal tubule is a common structural component in medical devices, mainly used to support and protect internal structures. For example, the distal tubule in a balloon dilation catheter is usually used to fix and protect the balloon and ensure its stable movement within the blood vessel.

[0003] In related technologies, the control method for plastic tube stretching and diameter reducing equipment refers to setting parameters such as heating temperature, stretching speed, and stretching length, and using manual operation or simple electrical switch control to locally heat and physically stretch the plastic tubing, reducing its outer diameter while keeping its inner diameter unchanged, to meet the assembly requirements of medical products. Typically, a constant-temperature heater is used to heat the outer surface of the tubing, and the length stretching is completed by a mechanical stretching device such as a slide rail motor or hydraulic cylinder, combined with cooling fan cooling and shaping. The control method uses relay logic or time relay sequential control.

[0004] Regarding the aforementioned technologies, the current relay logic is relatively simple. It directly clamps both ends of the conduit and stretches it without processing the stretched conduit. If the outer diameter of the conduit does not shrink to the specified size during the stretching process, manual intervention is required, which makes it impossible to achieve full automation and leaves room for improvement. Summary of the Invention

[0005] To address the issue that manual intervention is required when the outer diameter of the conduit does not shrink to the specified size during the stretching process, thus preventing full automation, this invention provides a method for stretching variable diameter plastic pipes and a stretching forming machine.

[0006] In a first aspect, the present invention provides a method for stretching a variable-diameter plastic tube, employing the following technical solution:

[0007] A method for stretching a variable diameter plastic tube, comprising:

[0008] Step S1: In response to a preset stretching signal, obtain the raw material dimensions and the forming dimensions;

[0009] Step S2: Determine a stretching scheme based on the raw material dimensions and the forming dimensions, and execute the stretching scheme;

[0010] Step S3: Determine the inspection hole diameter specification based on the molding dimensions;

[0011] Step S4: Determine the inspection plan based on the inspection aperture specification. The inspection plan is to press the plastic tube that has completed the stretching process to insert it into the aperture corresponding to the inspection aperture specification.

[0012] Step S5: After completing the stretching procedure, execute the inspection procedure and obtain the inspection image;

[0013] Step S6: Analyze the examination image based on preset catheter characteristics to obtain the large-diameter region;

[0014] Step S7: When the large-diameter region exists, update the raw material size based on the large-diameter region and repeat steps S2 to S6 until the large-diameter region no longer exists;

[0015] Step S8: Output a preset stretching completion signal when the large diameter region does not exist.

[0016] By adopting the above technical solution, the stretching scheme is determined according to the molding size and the raw material size. After stretching, the finished product is inspected to see if the outer diameter has been reduced to the required size. If the required size is reached, the guide tube will fall into the inspection hole. If the requirements cannot be met, it will stay on the surface of the inspection cylinder. The area of ​​the guide tube that does not meet the requirements is determined according to the size of the area where it stays. Then, the guide tube area that does not meet the requirements is stretched again until the requirements are met. Automatic inspection and calibration are performed without manual operation, which improves the pass rate and automation of stretching of variable diameter plastic tubes.

[0017] Optionally, the specific method for determining the stretching scheme based on the raw material size and the forming size, and for executing the stretching scheme, includes:

[0018] Step S20: Determine the heating clamping end point and the physical clamping end point based on the material dimensions;

[0019] Step S21: Form a heating trajectory based on the heated clamping end point and the physical clamping end point;

[0020] Step S22: Determine the stretching trajectory based on the forming dimensions and the physical clamping endpoints;

[0021] Step S23: After heating is completed according to the heating trajectory, clamp the heating clamping end and the physical clamping end respectively, then stretch according to the stretching trajectory, and obtain a stretching thermal image;

[0022] Step S24: Analyze the heat loss area based on the tensile thermal image;

[0023] Step S25: Update the heating trajectory based on the heat loss area and reheat according to the heating trajectory until the stretching trajectory is completed.

[0024] By adopting the above technical solution, it is necessary to ensure that the temperature is at the thermal extension level during the stretching process. Therefore, when a certain area in the middle loses heat quickly, that area is reheated, which ensures the duct's extensibility and improves the efficiency of duct stretching and forming.

[0025] Optionally, the method of updating the heating trajectory based on the heat loss region and re-completing the heating according to the heating trajectory until the stretching trajectory is completed includes:

[0026] Step S250: When the heat loss region exists, execute the inspection plan and obtain the inspection image, and define the inspection image as an intermediate inspection image;

[0027] Step S251: Analyze the mid-course inspection image based on the duct features and the tensile thermal image to obtain the mid-course large-diameter region;

[0028] Step S252: When the large diameter region in the middle completely includes the heat loss region, continue stretching directly according to the stretching trajectory without reheating;

[0029] Step S253: When the intermediate large diameter region does not completely contain the heat loss region, update the heating trajectory based on the heat loss region and re-complete the heating according to the heating trajectory until the stretching trajectory is completed.

[0030] By adopting the above technical solution, if this part of the low-heat conduit has been stretched and meets the requirements, then there is no need to continue stretching, and therefore no need to continue conducting heat, which reduces the heating work and improves the stretching efficiency.

[0031] Optionally, it also includes a method for determining whether to perform the inspection scheme when the heat loss region exists, the method comprising:

[0032] Step S2500: Determine the heat loss length based on the heat loss region;

[0033] Step S2501: Based on the molding dimensions, find the corresponding shortest recess length from the preset recess database;

[0034] Step S2502: Execute the inspection plan when the heat loss length is greater than the shortest indentation length;

[0035] Step S2503: When the heat loss length is less than the shortest concave length, update the heating trajectory directly based on the heat loss region.

[0036] By adopting the above technical solution, if the unheated area is short, there is no need to check whether the area meets the requirements, because it is very likely that the area cannot be inspected through the inspection hole.

[0037] Optional, also includes:

[0038] Step S254: Analyze the intermediate inspection image based on the catheter characteristics to obtain the forming area and the corresponding heat level;

[0039] Step S255: Compare the heat level with the preset stretching heat level to obtain the stretching and forming area, wherein the heat level corresponding to the stretching and forming area is greater than the stretching heat level;

[0040] Step S256: Determine a cooling scheme based on the extended forming area;

[0041] Step S257: The cooling scheme is executed either by continuing to stretch along the stretching trajectory without reheating or by updating the heating trajectory based on the heat loss area and reheating along the heating trajectory until the stretching trajectory is completed.

[0042] By adopting the above technical solution, the stretched areas can also be inspected during the intermediate inspection process. These areas can be cooled to prevent them from being stretched further, thereby improving the yield and reducing the defect rate.

[0043] Optional, also includes:

[0044] Step S9: When the large diameter region does not exist, determine the unqualified inspection hole diameter specification based on the forming size. The hole diameter value corresponding to the unqualified inspection hole diameter specification and the hole diameter value corresponding to the inspection hole diameter specification differ by a preset deviation threshold value.

[0045] Step S10: Determine the non-conforming inspection plan based on the non-conforming inspection aperture specification. The non-conforming inspection plan is to press the plastic tube that has completed the inspection plan so as to insert it into the aperture corresponding to the non-conforming inspection aperture specification.

[0046] Step S11: After executing the non-conforming inspection plan, obtain the verification inspection image;

[0047] Step S12: Analyze the verification image based on preset catheter features to obtain the disappearance region;

[0048] Step S13: When the disappearing area does not exist, output the preset stretching completion signal normally;

[0049] Step S14: Output a preset stretching overload signal when the disappearing region exists.

[0050] By adopting the above technical solution, although the product can fall into the inspection hole of the corresponding space, there may be cases where the stretching is too excessive and the inspection hole is too small. In this case, the finished product is checked and inspected through a hole with a diameter smaller than the inspection hole. If a part falls into the corresponding hole, it means that the outer diameter of the conduit in this part is too small and does not meet the requirements. Automatic inspection and calibration improve the pass rate of stretching of variable diameter plastic pipe.

[0051] Optionally, the method for normally outputting a stretching completion signal when the disappeared region does not exist includes:

[0052] Step S130: When the disappearance area does not exist, execute the preset tip tapping scheme. The tip tapping scheme is to tap the plastic tube that has completed the non-conforming inspection scheme along the length direction of the hole corresponding to the non-conforming inspection aperture specification after executing the non-conforming inspection scheme, and obtain the side image of the conduit.

[0053] Step S131: Analyze the height curve of the catheter based on the catheter side image and catheter features;

[0054] Step S132: Analyze the height curve on the catheter to determine the zero height intersection point;

[0055] Step S133: Output the stretching overload signal when the zero height intersection point exists;

[0056] Step S134: Output the stretching completion signal when the zero height intersection does not exist.

[0057] By adopting the above technical solution, even if the part is qualified, it may still be unqualified. If the length of this part is too short, it cannot be inserted into the hole for inspection. Therefore, by tapping with a pointed tip and obtaining the height of the upper end, if there is a problem, the height curve will disappear, indicating that this part has been inserted into the hole. At this time, the overstretching problem has been detected, and the overstretching signal can be directly output, which improves the accuracy of the inspection of unqualified parts.

[0058] Optionally, another method for normally outputting the stretching completion signal when the vanished region does not exist includes:

[0059] Step S135: When the disappearing area does not exist, execute the preset outward stretching scheme. The outward stretching scheme is to execute the non-conforming inspection scheme while moving the plastic tube that has completed the non-conforming inspection scheme outward along the length direction of the hole corresponding to the non-conforming inspection aperture specification, and obtain the image of the hole opening area.

[0060] Step S136: Analyze the image of the orifice region to obtain the orifice height of the conduit;

[0061] Step S137: During the execution of the outward stretching scheme, when the height of the guide orifice is always greater than or equal to 0, output the stretching completion signal;

[0062] Step S138: When the height of the conduit orifice is equal to 0 during the execution of the outward stretching scheme, output the overstretching signal.

[0063] By adopting the above technical solution, if the length that is not met is relatively short, the end face pressing method can also be adopted. If there is a situation where the length is not met, the height will be equal to 0, and the surface part has been inserted into the hole. At this time, the overstretching situation has been detected, and the overstretching signal can be directly output, which improves the accuracy of the inspection of non-conforming situations. Compared with the above-mentioned knocking solution, one device can be reduced, saving physical costs.

[0064] Secondly, the present invention provides a stretch forming machine, which adopts the following technical solution:

[0065] A stretch forming machine, employing a variable diameter plastic tube stretching method as described above, comprising:

[0066] The worktable serves as the carrier of the molding machine;

[0067] Guide rails are mounted on the worktable to form a stretching track;

[0068] A heating clamping block is provided on the workbench and located at one end of the guide rail. The heating clamping block is provided with a clamping hole for clamping and heating one end of the guide tube to be stretched.

[0069] A slide table is slidably connected to a guide rail. A motor controlling the slide table's movement is located at the end of the guide rail furthest from the heating clamping block. A first clamping block is mounted on the slide table, and a drive cylinder is also mounted on the slide table. A second clamping block, which cooperates with the first clamping block to clamp the other end of the guide tube to be stretched, is mounted on the piston rod of the drive cylinder.

[0070] A hair dryer, located on one side of the guide rail, is used to cool the stretched and shaped conduit.

[0071] Optional, also includes:

[0072] The slide rail is located on the worktable;

[0073] The first robotic arm is slidably connected to a slide rail to grip the conduit and move it to different work positions;

[0074] The inspection cylinder is rotatably connected to the workbench. The inspection cylinder is provided with a first test hole to check whether the guide tube to be stretched is qualified, and a second test hole to check whether the guide tube to be stretched is unqualified. The first test hole and the second test hole are alternately arranged.

[0075] A pressing bracket, mounted on a workbench, has a pressing plate slidably connected to it for pressing the guide tube on the inspection cylinder; and

[0076] The second robotic arm is slidably connected to the slide rail, and the second robotic arm is equipped with a striking block for striking the guide tube on the inspection cylinder.

[0077] In summary, the present invention has at least one of the following beneficial technical effects:

[0078] Through the use of stretching and inspection schemes, automatic inspection and calibration are performed without the need for manual operation, thereby improving the pass rate and automation of stretching of variable diameter plastic pipes.

[0079] By implementing a non-compliance inspection plan, the completed products are checked and inspected automatically, which improves the pass rate of tensile testing of variable diameter plastic pipes. Attached Figure Description

[0080] Figure 1 This is a schematic diagram of the structure of a stretch forming machine according to Embodiment 1 of this application;

[0081] Figure 2 This is a schematic diagram of the structure of the heating clamping block in Embodiment 1 of this application;

[0082] Figure 3 This is a schematic diagram of the structure of a stretch forming machine according to Embodiment 2 of this application;

[0083] Figure 4 This is a flowchart of a method for stretching a variable-diameter plastic tube according to Embodiment 3 of this application;

[0084] Figure 5 This is a schematic diagram of the inspection image in Embodiment 3 of this application;

[0085] Figure 6 This is a schematic diagram of the verification image in Embodiment 3 of this application;

[0086] Figure 7 This is a schematic diagram of the mid-process inspection image in Embodiment 3 of this application;

[0087] Figure 8 This is a schematic diagram of the height curve on the catheter in Embodiment 3 of this application;

[0088] Figure 9 This is a schematic diagram of the aperture area image in Embodiment 3 of this application.

[0089] The parts referred to by the numbers in the above attached diagrams are as follows: 1. Worktable; 2. Guide rail; 21. Motor; 3. Heating clamping block; 31. Adjusting block; 32. Mounting block; 321. Insertion hole; 33. Clamping hole; 4. Slide table; 41. First clamping block; 42. Drive cylinder; 43. Second clamping block; 5. Blower; 6. Slide rail; 61. First robotic arm; 62. Second robotic arm; 621. Tapping block; 7. Inspection cylinder; 71. First test hole; 72. Second test hole; 8. Pressing bracket; 81. Pressing plate. Detailed Implementation

[0090] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0091] This application discloses a stretch forming machine. Example 1

[0092] Reference Figure 1 A stretch forming machine includes a worktable 1, a guide rail 2, a heating clamping block 3, a slide table 4, and a blower 5. The guide rail 2 is mounted on the worktable 1 to form a stretching track.

[0093] Combined with the diagram Figure 2 A heated clamping block 3 is mounted on the worktable 1 and located at one end of the guide rail 2. The heated clamping block 3 has clamping holes 33 for clamping the guide tube to be stretched. Here, the heated clamping block 3 includes an adjusting block 31 and a mounting block 32. The mounting block 32 is fixed to the worktable 1 and has insertion holes 321. The adjusting block 31 is inserted into the insertion holes 321 and then fixed with screws, the screw heads abutting against the adjusting block 31 to fix the adjusting block 31 to the mounting block 32. The clamping holes 33 are located on the adjusting block 31. By disassembling the adjusting block 31, adjusting blocks 31 of different sizes corresponding to the clamping holes 33 can be installed to clamp guide tubes of different sizes to be stretched. The number of insertion holes 321 is several and arranged along the width direction of the mounting block 32, allowing clamping at different positions.

[0094] The slide table 4 is slidably connected to the guide rail 2. A motor 21 for controlling the sliding of the slide table 4 is installed at the end of the guide rail 2 away from the heating clamping block 3. The slide table 4 has a first clamping block 41 and a drive cylinder 42. A second clamping block 43 is installed on the piston rod of the drive cylinder 42, which works in conjunction with the first clamping block 41 to clamp the other end of the guide tube to be stretched.

[0095] The blower 5 is mounted on one side of the guide rail 2 to cool the stretched and shaped conduit.

[0096] The implementation principle of Example 1 is as follows: one end of the conduit is inserted into the heating clamping block 3 for clamping and heating, and the other end is inserted between the first clamping block 41 and the second clamping block 43. The driving cylinder 42 is driven so that the first clamping block 41 cooperates with the second clamping block 43 to clamp the other end of the conduit. Then, the motor 21 drives the slide table 4 to move a pre-calculated distance to the other side so that the conduit is stretched to the specified size. Then, the blower 5 is used for cooling to complete the stretching. Example 2

[0097] Reference Figure 3 This embodiment differs from Embodiment 1 in that it further includes a slide rail 6, a first robotic arm 61, an inspection cylinder 7, a pressing bracket 8, and a second robotic arm 62. The slide rail 6 is mounted on the worktable 1 to provide a sliding track for the first robotic arm 61 and the second robotic arm 62. The first robotic arm 61 is slidably connected to the slide rail 6 to clamp the conduit and move it to different workstations. The inspection cylinder 7 is rotatably connected to the worktable 1. The inspection cylinder 7 has a first test hole 71, the inner diameter of which is the same as the outer diameter of the stretched conduit. The first test hole 71 is set along the length of the inspection cylinder 7 to check whether the dimensions of the conduit to be stretched are qualified. The inspection cylinder 7 also has a second test hole 72, the inner diameter of which is smaller than the outer diameter of the stretched conduit by a preset allowable deviation value. The second test hole 72 is set along the length of the inspection cylinder 7 to check whether the conduit to be stretched is unqualified. The first test hole 71 and the second test hole 72 are alternately arranged.

[0098] The pressing bracket 8 is mounted on the workbench 1, and a pressing plate 81 is slidably connected to the pressing bracket 8 in the vertical direction to press the conduit on the inspection cylinder 7. The second robotic arm 62 is slidably connected to the slide rail 6, and the second robotic arm 62 has a striking block 621 for striking the conduit on the inspection cylinder 7 to drive the conduit that conforms to the first test hole 71 or the second test hole 72.

[0099] In this embodiment of the application, the first robotic arm 61 and the second robotic arm 62 each have a corresponding drive source to drive the first robotic arm 61 and the second robotic arm 62 to move along the length direction of the slide rail 6.

[0100] The implementation principle of Example 2 is as follows: One end of the conduit is inserted into the heating clamping block 3 for clamping and heating, and the other end is inserted between the first clamping block 41 and the second clamping block 43. The driving cylinder 42 is driven so that the first clamping block 41 cooperates with the second clamping block 43 to clamp the other end of the conduit. Then, the motor 21 drives the slide table 4 to move a pre-calculated distance to the other side so that the conduit is stretched to the specified size. Then, the conduit is cooled by the blower 5 to complete the stretching. Then, the first robotic arm 61 clamps the conduit to the first test hole 71 or the second test hole 72 of the inspection cylinder 7. The pressing plate 81 slides along the pressing bracket 8 to press the conduit into the first test hole 71 or the second test hole 72 to obtain the inspection result. If it is completely exposed outside the first test hole 71 or the second test hole 72, the striking block 621 on the second robotic arm 62 is driven to strike the conduit. Example 3

[0101] Based on the same inventive concept, embodiments of the present invention provide a method for stretching a variable diameter plastic tube.

[0102] Reference Figure 4 A method for stretching variable diameter plastic pipes, applied to a stretching forming machine according to Embodiment 2 above, includes:

[0103] Step S1: In response to a preset stretching signal, obtain the raw material size and the forming size.

[0104] The stretching signal indicates that the guide tube to be stretched has been placed and the stretching forming machine is ready to perform the stretching operation. This response can be obtained by manually pressing the corresponding button. The raw material size is the size of the guide tube before stretching, including length, outer diameter, and inner diameter. The forming size is the size of the guide tube after stretching, and the data type is the same as the raw material size, including length, outer diameter, and inner diameter. This can be obtained by manual input.

[0105] Step S2: Determine the stretching scheme based on the raw material size and forming size, and execute the stretching scheme.

[0106] The stretching scheme involves clamping and stretching both ends of the catheter to be stretched. The specific method for determining the scheme is described in subsequent steps and will not be repeated here.

[0107] Step S3: Determine the inspection hole diameter specification based on the molding dimensions.

[0108] The inspection aperture specification is the aperture of the first test hole 71, for example, 0.5cm. It is determined by finding the outer diameter of the conduit in the forming dimensions; this outer diameter is the inner diameter of the first test hole 71. For example, if the forming dimensions are: length 20cm, outer diameter 0.5cm, inner diameter 0.3cm, then the inner diameter of the first test hole 71 is 0.5cm. The inspection cylinder 7 has different aperture specifications to inspect different conduit outer diameters.

[0109] Step S4: Determine the inspection plan based on the inspection aperture specifications.

[0110] The testing procedure involves placing the plastic tube that has completed the tensile test onto the hole corresponding to the test hole diameter specification, i.e., above the first test hole 71, and then pressing it to insert it into the hole corresponding to the test hole diameter specification.

[0111] The method for determining this is to have a standard inspection plan in advance, in which only the first test hole 71 is not specified. Then, when the test hole diameter specification is known, it can be filled into the standard plan and executed.

[0112] Step S5: After completing the stretching procedure, execute the inspection procedure and obtain the inspection images.

[0113] The inspection image is an image of the guide tube on the inspection cylinder 7 inserted into the first test hole 71 after the inspection plan has been executed, such as... Figure 5 As shown. Taken by a side-facing camera.

[0114] Step S6: Analyze the examination image based on the preset duct features to obtain the large-diameter region.

[0115] The catheter characteristics are those unique to the catheter, such as grayscale values. The large-diameter region is the area on the catheter whose diameter is larger than the first test hole 71. For example... Figure 5 As shown, the portion of the conduit protruding above the inspection cylinder 7... Figure 5 Regions a and b in the diagram represent the large-diameter regions. Because the conduit in these regions cannot be squeezed into the first test hole 71, it remains exposed and is captured by the camera. The analysis is performed through feature comparison.

[0116] Step S7: If the large diameter region exists, update the raw material size based on the large diameter region and repeat steps S2 to S6 until the large diameter region no longer exists.

[0117] The update method is to define the raw material size as Figure 5 The lengths of region a and region b in the text refer to the two ends that clamp region a and the two ends that clamp region b.

[0118] When a large-diameter area exists, it means that some areas do not meet the requirements of the forming size, so it is necessary to continue stretching. The area to be stretched is the corresponding large-diameter area.

[0119] Step S8: Output a preset stretching completion signal when the large diameter region does not exist.

[0120] The stretching completion signal indicates that stretching is complete and the parts can be disassembled. The absence of a large-diameter region indicates that the outer diameter at all locations meets the requirements, thus signifying that stretching is complete.

[0121] Step S9: When the large diameter region does not exist, determine the non-conforming inspection hole diameter specification based on the forming size.

[0122] The difference between the aperture value corresponding to the non-conforming inspection aperture specification and the aperture value corresponding to the inspection aperture specification is a preset deviation threshold value. The deviation threshold value is a manually defined maximum deviation; anything less than this value fails to meet the requirements. This value is manually set. The non-conforming inspection aperture specification is the diameter of the second test hole 72, which indicates excessive stretching and an excessively small outer diameter if the outer diameter of the conduit is smaller than this value, thus failing to meet the requirements. It is determined by subtracting the deviation threshold value from the outer diameter corresponding to the forming size.

[0123] When the large-diameter area does not exist, although the stretching is completed, it is still necessary to check whether the stretching is excessive, so there are still subsequent non-conforming inspection steps.

[0124] Step S10: Determine the non-conforming inspection plan based on the non-conforming inspection aperture specifications.

[0125] The non-conforming inspection plan involves pressing the completed plastic tube into the hole corresponding to the non-conforming inspection aperture specification. The determination method is similar to step S4 and will not be repeated here.

[0126] Step S11: Obtain the verification inspection image after executing the non-conforming inspection plan.

[0127] The verification image is the image of the guide tube on the inspection cylinder 7 inserted into the second test hole 72 after the non-conforming inspection plan has been executed. Figure 6 As shown. Taken by a side-facing camera.

[0128] Step S12: Analyze the verification image based on the preset catheter features to obtain the disappearance area.

[0129] The disappearance area is the region where the catheter's characteristics disappear, specifically the area on the catheter with a diameter less than or equal to the second test hole 72. For example... Figure 6 As shown, the area beyond the exposed portion of the conduit above the inspection cylinder 7, Figure 6Region c in the image represents the disappearance region, because the conduit in this region is squeezed into the second test hole 72, indicating that the diameter of this region does not meet the requirements. The analysis was performed by comparing the image with that of a standard conduit placed above the second test hole 72.

[0130] Step S13: Output the stretching completion signal normally when the disappearing area does not exist.

[0131] When there is no disappearing area, it means that the outer diameter of the conduit at all locations meets the requirements, and the stretching completion signal is output normally.

[0132] Step S14: Output a preset stretching overload signal when the disappearing region exists.

[0133] The overstretch signal indicates that the conduit is overstretched, or that the diameter is too small in some areas. The output can be either text or a flashing indicator light.

[0134] The presence of a disappearing region indicates that the outer diameter of the catheter in some areas is excessively stretched and does not meet the requirements, so an excessive stretching signal is output.

[0135] The specific methods for determining and implementing the stretching scheme based on the raw material dimensions and forming dimensions include:

[0136] Step S20: Determine the heating clamping end point and the physical clamping end point based on the material size.

[0137] The heated clamping endpoint is one end of the conduit held by the heated clamping block 3. The physical clamping endpoint is the other end of the conduit held by the first clamping block 41 and the second clamping block 43. The method here is to arbitrarily select one end as the heated clamping endpoint, and then calculate the position of the other endpoint according to the material size. For example, if the length of the material is 18cm, then the first heated clamping endpoint is 0, and the other is the point at the 18cm position.

[0138] Step S21: Form a heating trajectory based on the heated clamping end point and the physical clamping end point.

[0139] The heating trajectory is the path for heating the raw material. This trajectory involves the first clamping block 41 and the second clamping block 43 gradually moving from the heated clamping end to the physical clamping end, thus gradually heating the conduit. During this process, the point of contact between the conduit and the heated clamping block 3 gradually moves from one side near the slide table 4 to the other end, meaning the heating position gradually moves.

[0140] Step S22: Determine the stretching trajectory based on the forming dimensions and physical clamping endpoints.

[0141] The stretching trajectory is the path of the slide 4 as it moves during the stretching of the guide tube after clamping is complete. It is determined by stretching from the physical clamping end point to the position corresponding to the formed size. For example, if the physical clamping end point is 18cm, and the corresponding position for the formed size is 20cm, then the stretching trajectory is from the 18cm position to the 20cm position.

[0142] Step S23: After heating is completed according to the heating trajectory, clamp the heating clamping end and the physical clamping end respectively, then stretch according to the stretching trajectory and obtain the stretching thermal image.

[0143] The stretching thermal image is a thermal imaging image of the conduit during the stretching process. It is acquired by taking pictures with an infrared thermal imaging camera.

[0144] Step S24: Analyze the heat loss area based on the stretched thermal image.

[0145] The heat loss area is the region where heat is lost. The analysis here involves analyzing the colors of the stretched thermal image. If the color does not match the required temperature or appears as black, it indicates a heat loss area.

[0146] Step S25: Update the heating trajectory based on the heat loss area and reheat according to the heating trajectory until the stretching trajectory is completed.

[0147] The purpose of the update is to ensure that the corresponding area continues to be heated to the stretching temperature, so as to avoid the situation where the temperature is too low and the stretching is not obvious or not at all.

[0148] The method of updating the heating trajectory based on the heat loss region and reheating according to the heating trajectory until the stretching trajectory is completed includes:

[0149] Step S250: When a heat loss region exists, execute the inspection plan and acquire an inspection image, which is then defined as an intermediate inspection image.

[0150] The purpose of this inspection is to check whether the conduit corresponding to the heat loss area has been stretched to the specified outer diameter.

[0151] Step S251: Analyze the mid-path inspection image based on duct features to obtain the mid-path large-diameter region.

[0152] The large-diameter region in the middle is the large-diameter region in the intermediate test image. The analysis method here is similar to that in step S6, the difference being that one is a test image, while this is an intermediate test image, so it will not be described again.

[0153] Step S252: When the large diameter area in the middle does not contain any heat loss area, continue stretching directly according to the stretching trajectory without reheating.

[0154] If the major diameter region in the middle section does not contain the heat loss region at all, it means that the heat loss region has been stretched to the specified outer diameter, which meets the requirements. Therefore, no further heating is needed, and stretching can continue directly along the stretching trajectory without reheating. Here, "completely not containing" means that, in image analysis, the coordinates of all pixels in the heat loss region are not located inside the circumscribed polygon of the major diameter region.

[0155] Step S253: When the large diameter area in the middle does not completely contain the heat loss area, update the heating trajectory based on the heat loss area and reheat according to the heating trajectory until the stretching trajectory is completed.

[0156] If the large diameter area in the middle does not completely include the heat loss area, it means that the part of the conduit corresponding to the heat loss area still needs to be stretched, so it still needs to be heated. Then, the heating trajectory is updated based on the heat loss area and the heating is completed again according to the heating trajectory until the stretching trajectory is completed.

[0157] Step S254: Analyze the intermediate inspection image based on the conduit features and the tensile thermal image to obtain the forming area and the corresponding heat level.

[0158] The formed area refers to the area that has already been formed, i.e., the area that has been embedded in the first test hole 71. This is obtained through analysis of the conduit features, similar to the method in step S12, and will not be elaborated upon here. Figure 7 The area shown is d. The heat level refers to whether the heat in the forming area meets the requirements for stretching and elongation. Here, it can be represented as the ratio of the current temperature to the optimal stretching temperature. The analysis method is to place the forming area in the stretching thermal image, obtain the color of the corresponding forming area, determine the corresponding temperature through the color, and then divide it by the optimal stretching temperature.

[0159] The optimal temperature for stretching here is set manually.

[0160] Step S255: Compare the heat level with the preset stretching heat level to obtain the stretching and forming area.

[0161] The degree of heat of stretching refers to the extent to which the heat required for stretching meets the stretching requirements. The degree of heat corresponding to the stretching forming area is greater than the degree of heat of stretching. This can be represented by the optimal temperature for stretching, or by a manually set optimal temperature for stretching. For example, the optimal temperature for stretching may be 100℃, but stretching can also be performed at temperatures lower than that, such as a manually set optimal temperature of 80℃.

[0162] The stretching and forming area refers to the already formed area. The comparison method is to compare the heat level of all areas with the stretching heat level; if it is greater than the stretching heat level, then it is considered part of the stretching and forming area.

[0163] Step S256: Determine the cooling scheme based on the extended forming area.

[0164] The cooling scheme is a method for cooling the extended forming area. It can be determined by first having a standard cooling scheme, which cools the area on the conduit, and then, before that area is input until the extended forming area appears, input that area into the standard cooling scheme to obtain the final cooling scheme.

[0165] Step S257: A cooling scheme is executed during the process of either continuing to stretch along the stretching trajectory without reheating or updating the heating trajectory based on the heat loss area and reheating along the heating trajectory until the stretching trajectory is completed.

[0166] The purpose of implementing the cooling scheme is to prevent, or as much as possible, the already stretched conduit area from continuing to stretch and thus failing to meet requirements.

[0167] This includes a method for determining whether to execute an inspection plan when a heat loss region exists, the method comprising:

[0168] Step S2500: Determine the heat loss length based on the heat loss region.

[0169] The heat loss length is the length of the heat loss region. It can be determined by subtracting the coordinates of the two endpoints. For example, if the heat loss region is (1cm~5cm) after coordinate conversion, the heat loss length is 5cm minus 1cm, which gives a heat loss length of 4cm.

[0170] Step S2501: Based on the molding dimensions, find the corresponding shortest recess length from the preset recess database.

[0171] The shortest recessed length is the length of the conduit required to enter the first test hole 71, equal to the inner diameter of the first test hole 71. Although some conduits are small enough to easily enter the first test hole 71, their structural elongation characteristics prevent them from fully extending into the first test hole 71. Therefore, the length of the conduit capable of entering the first test hole 71 needs to be sufficiently long. A mapping relationship between the molded size and the shortest recessed length is stored in the database. A conduit with a portion of its outer diameter (the molded size) and a portion of its original outer diameter is placed on the first test hole 71 for testing. The length of the portion representing the molded outer diameter is gradually increased from 0 until it is recessed into the first test hole 71. This length is measured and recorded as the shortest recessed length. When the system receives the corresponding molded size, it automatically retrieves the corresponding shortest recessed length from the database and outputs it.

[0172] Step S2502: Execute the inspection plan when the heat loss length is greater than the shortest indentation length.

[0173] If the heat loss length is greater than the shortest recess length, it indicates that the area may be recessed into the first test hole 71, and it is possible that the heat loss area has been stretched. Therefore, the inspection plan is executed.

[0174] Step S2503: When the heat loss length is less than the shortest concave length, update the heating trajectory directly based on the heat loss region.

[0175] When the heat loss length is less than the shortest recess length, it means that even if the area is stretched, it will not be recessed into the first test hole 71. Therefore, it is impossible to determine whether the heat loss area may have been stretched. Thus, it is assumed that the stretching is not complete and heating is performed directly. Therefore, the heating trajectory is updated directly based on the heat loss area.

[0176] The methods for normally outputting a stretching completion signal when the disappearing region does not exist include:

[0177] Step S130: When the disappearance area does not exist, execute the preset tip tapping scheme and obtain a side image of the catheter.

[0178] The tip-tapping method involves tapping the plastic tube along the length of the hole corresponding to the non-conforming inspection aperture specification after the non-conforming inspection plan has been executed. The side image of the tube is the inspection image after tapping. The acquisition method is similar to step S5 and will not be described in detail here.

[0179] Step S131: Analyze the height curve of the catheter based on the catheter side image and catheter features.

[0180] The height curve of the catheter is the curve representing the height of the uppermost part of the catheter. The analysis can be performed by directly determining the catheter region based on its characteristics, and then identifying the upper edge line, which is the height curve of the catheter. It should be noted that if the catheter is inserted into the second test port 72, then the height curve of the catheter is the upper edge line of the detection cylinder, such as... Figure 8 As shown, regions e and g are both the upper edge lines of the conduit, while region f is the upper edge line of the second test hole 72.

[0181] Step S132: Analyze the height curve on the catheter to determine the zero height intersection point.

[0182] The zero-height intersection is the intersection of the sidewalls of the conduit and the second test hole 72. The analysis method is to regard the upper edge line of the first test hole 71 as zero height, and then if the height in the height curve on the conduit also has a zero height, then there is a zero-height intersection.

[0183] Step S133: Output an overstretch signal when the zero-height intersection point exists.

[0184] The presence of a zero-height intersection indicates that part of the conduit has entered the second test hole 72, meaning that part of the conduit does not meet the requirements and is overstretched, thus outputting an overstretch signal.

[0185] Step S134: Output a stretching completion signal when the zero-height intersection does not exist.

[0186] If the zero-height intersection does not exist, it means that the conduit has not entered the area of ​​the second test hole 72, which meets the requirements. Therefore, the stretching completion signal is output.

[0187] Another method for outputting a stretching completion signal normally when the disappearing region does not exist includes:

[0188] Step S135: When the disappearing region does not exist, execute the preset outward stretching scheme and obtain the image of the orifice region.

[0189] The outward stretching method involves moving the plastic tube that has completed the non-conforming inspection outward along the length of the hole corresponding to the non-conforming inspection aperture specification while performing the non-conforming inspection procedure.

[0190] An image of the orifice region is an image of the area around the orifice, such as... Figure 9 As shown.

[0191] Step S136: Analyze the image of the orifice region to obtain the orifice height of the conduit.

[0192] The height of the conduit orifice is the height of the conduit at the position of the second test hole 72, such as Figure 9 In this context, 'h' represents the height of the duct orifice. The analysis method involves first determining the position of the orifice. If the camera position is fixed, the straight line containing the orifice in the orifice region image is fixed. Therefore, we can directly input the duct features along this line and analyze them to obtain the highest point of the duct features at that straight line position in the orifice region image.

[0193] Step S137: Output a stretching completion signal when the height of the guide tube orifice is always greater than or equal to 0 during the outward stretching process.

[0194] If the height of the guide tube orifice is always greater than or equal to 0, it means that the outer diameter of the guide tube is always greater than the outer diameter of the second test hole 72, which meets the stretching requirements, and a stretching completion signal can be output.

[0195] Step S138: When the height of the guide tube orifice is equal to 0 during the execution of the outward stretching scheme, output an overstretching signal.

[0196] If the height of the conduit orifice is equal to 0 during the outward stretching process, it indicates that the outer diameter of part of the conduit is equal to the outer diameter of the second test hole 72. If the deviation is too large, the stretching is excessive, and an overstretching signal is output.

Claims

1. A method for stretching a variable diameter plastic tube, characterized in that, include: Step S1: In response to a preset stretching signal, obtain the raw material dimensions and the forming dimensions; Step S2: Determine a stretching scheme based on the raw material dimensions and the forming dimensions, and execute the stretching scheme; Step S3: Determine the inspection hole diameter specification based on the molding dimensions; Step S4: Determine the inspection plan based on the inspection aperture specification. The inspection plan is to press the plastic tube that has completed the stretching process to insert it into the aperture corresponding to the inspection aperture specification. Step S5: After completing the stretching procedure, execute the inspection procedure and obtain the inspection image; Step S6: Analyze the examination image based on preset catheter characteristics to obtain the large-diameter region; Step S7: When the large-diameter region exists, update the raw material size based on the large-diameter region and repeat steps S2 to S6 until the large-diameter region no longer exists; Step S8: Output a preset stretching completion signal when the large-diameter region does not exist; The specific method for determining the stretching scheme based on the raw material size and the forming size, and for executing the stretching scheme, includes: Step S20: Determine the heating clamping end point and the physical clamping end point based on the material dimensions; Step S21: Form a heating trajectory based on the heated clamping end point and the physical clamping end point; Step S22: Determine the stretching trajectory based on the forming dimensions and the physical clamping endpoints; Step S23: After heating is completed according to the heating trajectory, clamp the heating clamping end and the physical clamping end respectively, then stretch according to the stretching trajectory, and obtain a stretching thermal image; Step S24: Analyze the heat loss area based on the tensile thermal image; Step S25: Update the heating trajectory based on the heat loss area and reheat according to the heating trajectory until the stretching trajectory is completed; The method of updating the heating trajectory based on the heat loss region and reheating according to the heating trajectory until the stretching trajectory is completed includes: Step S250: When the heat loss region exists, execute the inspection plan and obtain the inspection image, and define the inspection image as an intermediate inspection image; Step S251: Analyze the mid-path inspection image based on the catheter characteristics to obtain the mid-path large-diameter region; Step S252: When the large diameter region in the middle does not contain the heat loss region at all, continue stretching directly according to the stretching trajectory without reheating; Step S253: When the intermediate large diameter region does not completely contain the heat loss region, update the heating trajectory based on the heat loss region and re-complete the heating according to the heating trajectory until the stretching trajectory is completed.

2. The method for stretching a variable-diameter plastic tube according to claim 1, characterized in that, It also includes a method for determining whether to execute the inspection scheme when the heat loss region exists, the method comprising: Step S2500: Determine the heat loss length based on the heat loss region; Step S2501: Based on the molding dimensions, find the corresponding shortest recess length from the preset recess database; Step S2502: Execute the inspection plan when the heat loss length is greater than the shortest indentation length; Step S2503: When the heat loss length is less than the shortest concave length, update the heating trajectory directly based on the heat loss region.

3. The method for stretching a variable-diameter plastic tube according to claim 1, characterized in that, Also includes: Step S254: Analyze the intermediate inspection image based on the conduit features and the tensile thermal image to obtain the forming area and the corresponding heat level; Step S255: Compare the heat level with the preset stretching heat level to obtain the stretching and forming area, wherein the heat level corresponding to the stretching and forming area is greater than the stretching heat level; Step S256: Determine a cooling scheme based on the extended forming area; Step S257: The cooling scheme is executed either by continuing to stretch along the stretching trajectory without reheating or by updating the heating trajectory based on the heat loss area and reheating along the heating trajectory until the stretching trajectory is completed.

4. The method for stretching a variable-diameter plastic tube according to claim 1, characterized in that, Also includes: Step S9: When the large diameter region does not exist, determine the unqualified inspection hole diameter specification based on the forming size. The hole diameter value corresponding to the unqualified inspection hole diameter specification and the hole diameter value corresponding to the inspection hole diameter specification differ by a preset deviation threshold value. Step S10: Determine the non-conforming inspection plan based on the non-conforming inspection aperture specification. The non-conforming inspection plan is to press the plastic tube that has completed the inspection plan so as to insert it into the aperture corresponding to the non-conforming inspection aperture specification. Step S11: After executing the non-conforming inspection plan, obtain the verification inspection image; Step S12: Analyze the verification image based on preset catheter features to obtain the disappearance region; Step S13: When the disappearing area does not exist, output the preset stretching completion signal normally; Step S14: Output a preset stretching overload signal when the disappearing region exists.

5. The method for stretching a variable-diameter plastic tube according to claim 4, characterized in that, The method for normally outputting a stretching completion signal when the vanished region does not exist includes: Step S130: When the disappearance area does not exist, execute the preset tip tapping scheme. The tip tapping scheme is to tap the plastic tube that has completed the non-conforming inspection scheme along the length direction of the hole corresponding to the non-conforming inspection aperture specification after executing the non-conforming inspection scheme, and obtain the side image of the conduit. Step S131: Analyze the height curve of the catheter based on the catheter side image and catheter features; Step S132: Analyze the height curve on the catheter to determine the zero height intersection point; Step S133: Output the stretching overload signal when the zero height intersection point exists; Step S134: Output the stretching completion signal when the zero height intersection does not exist.

6. The method for stretching a variable diameter plastic tube according to claim 4, characterized in that, Another method for normally outputting the stretching completion signal when the vanished region does not exist includes: Step S135: When the disappearing area does not exist, execute the preset outward stretching scheme. The outward stretching scheme is to execute the non-conforming inspection scheme while moving the plastic tube that has completed the non-conforming inspection scheme outward along the length direction of the hole corresponding to the non-conforming inspection aperture specification, and obtain the image of the hole opening area. Step S136: Analyze the image of the orifice region to obtain the orifice height of the conduit; Step S137: During the execution of the outward stretching scheme, when the height of the guide orifice is always greater than or equal to 0, output the stretching completion signal; Step S138: When the height of the conduit orifice is equal to 0 during the execution of the outward stretching scheme, output the overstretching signal.

7. A stretch forming machine, employing the stretching method for a variable-diameter plastic tube as described in any one of claims 1 to 6, characterized in that, include: The workbench (1) serves as the carrier of the molding machine; Guide rail (2) is provided on the worktable (1) to form a stretching track; A heating clamping block (3) is provided on the workbench (1) and located at one end of the guide rail (2). The heating clamping block (3) is provided with a clamping hole (33) for clamping and heating one end of the guide tube to be stretched. A slide (4) is slidably connected to a guide rail (2). A motor (21) controlling the sliding of the slide (4) is provided at one end of the guide rail (2) away from the heating clamping block (3). A first clamping block (41) is provided on the slide (4). A drive cylinder (42) is provided on the slide (4). A second clamping block (43) is provided on the piston rod of the drive cylinder (42) to cooperate with the first clamping block (41) in clamping the other end of the guide tube to be stretched. A blower (5) is located on one side of the guide rail (2) to cool the stretched and formed conduit.

8. A stretch forming machine according to claim 7, characterized in that, Also includes: The slide rail (6) is located on the workbench (1); The first robotic arm (61) is slidably connected to the slide rail (6) to clamp the conduit and move it to different work positions; The inspection cylinder (7) is rotatably connected to the workbench (1). The inspection cylinder (7) is provided with a first test hole (71) to check whether the guide tube to be stretched is qualified. The inspection cylinder (7) is provided with a second test hole (72) to check whether the guide tube to be stretched is unqualified. The first test hole (71) and the second test hole (72) are alternately set. A pressing bracket (8) is provided on the workbench (1), and a pressing plate (81) is slidably connected to the pressing bracket (8) to press the guide tube on the inspection cylinder (7); and The second robotic arm (62) is slidably connected to the slide rail (6), and the second robotic arm (62) is provided with a striking block (621) for striking the guide tube on the inspection cylinder (7).

Images