Method for processing intersecting lines in large-radius variable-radius branch pipe

Abstract

The application discloses a large round corner variable radius branch pipe inner intersecting line machining method and particularly relates to the technical field of machining, which comprises the following steps: step one, modeling; step two, entering the machining module of UG, and adopting fixed contour milling; step three, taking the outer edge surface of a solid block as a reference, starting from the solid block 4 and corresponding inner intersecting lines, and removing the excess material of the inner intersecting lines which are not machined in place by means of grinding; and step four, designing an inspection sample plate according to the drawing requirements, accurately marking the inner intersecting lines according to the angle position of the inspection sample plate, and re-inspecting each area by using the inspection sample plate to confirm that the drawing requirements are met. The application accurately completes the linear control of the large round corner variable radius branch pipe inner intersecting line by means of the combined machining of milling and solid block copying grinding, designs the inspection sample plate according to the drawing acceptance standard for product inspection, and ensures that the machining size meets the drawing requirements.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and more specifically, to a method for machining the intersecting lines inside a branch pipe with a large fillet and variable radius. Background Technology

[0002] During the installation and water testing phase of the main pipeline primary circuit, the pipeline experienced system vibration due to the influence of fluid mechanics, posing a significant safety hazard to the system operation. Analysis revealed that this was caused by the unreasonable structure of the intersecting line of the integrated branch pipe B in the hot section of the main pipeline, which obstructed the flow of liquid. The solution is to process a gradually transitioning, variable-radius, large-rounded inner intersecting line on one side of the inner hole, which can fundamentally solve the problem. This design will be applied to other subsequent products.

[0003] The finished diameter of the inner hole is φ366.520 -3 mm, and the hole depth is 420 mm. From the integrated branch pipe opening along the axis of the inner hole, a rectangular coordinate system is established with the positive direction of the X-axis pointing to 0°. Within a half-circle range of 110°~0°~-110° in the clockwise direction, the radius of the part where the inner hole of the integrated pipe seat intersects with the main pipe needs to be machined from 9.50 -1.5 mm to 1270 -1.5 mm and then gradually back to 9.50 -1.5 mm. The inner radius of the remaining part of the circumference is 9.50 -1.5 mm. Before machining the intersection line of the large radius of the inner hole, the intersection line of the remaining inner holes is first machined according to 9.50 -1.5 mm.

[0004] Internal hole machining is usually considered to be done by adding a tool holder and a milling cutter to a boring machine. The effective fillet radius of the milling cutter is (cutter head diameter - tool holder diameter) / 2. If the tool holder is too long or too thin, it will affect the cutting stability and surface accuracy, and generate impact and vibration that will damage the boring machine. Obviously, the large fillet of the internal hole intersection line cannot be machined in one go. Moreover, the workpiece is used for the nuclear power primary circuit and welding is absolutely not allowed. Selecting appropriate tools and formulating a reasonable machining process for this workpiece, and using a three-dimensional template to assist in precise grinding can avoid the above-mentioned machining inadequacies, the risk of overcutting in some areas or out-of-tolerance fillet dimensions. Therefore, this invention proposes a machining method for the internal intersection line of a branch pipe with a large fillet variable radius. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a method for processing the intersecting line inside a branch pipe with a large fillet and variable radius, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for machining the intersection line inside a branch pipe with a large fillet and variable radius involves modeling using UG software and CNC programming using its machining module. The machining method includes the following steps:

[0008] Step 1: Modeling. Based on the finished drawing of the intersection line of the inner hole of the large fillet variable radius connector, only process the variable radius fillets within the intersection range of -110° to 110° in the inner hole of the integrated connector. Finally, determine the modeling style (model for processing). The chamfer adopts the variable radius edge chamfer. Input the corresponding radius values ​​R127, R115.3, R93.2, R65, R40.9, R24.6 and R15.2 at 0°, ±15°, ±30°, ±45°, ±60°, ±75° and ±90°.

[0009] Step 2: Enter the machining module of UG, use fixed contour milling, select a boring machine with a boring spindle diameter of φ110mm and a milling cutter head with a connecting part diameter of φ130mm and a maximum cutting outer diameter of φ320mm. Select standard milling cutters of Sangao models R335.25-315, 1721XL and 60-20L-R10, directly connect them to the end of the boring spindle, set a collision protection of 10mm for the inner hole, and at the same time reserve a 10mm safety distance to prevent interference and collision. Machining off the allowance within the range of approximately 85mm for the inner fillet radius, of which 42mm of allowance at the root of the inner fillet is not machined.

[0010] Step 3: Using the outer surface of the stainless steel 3D sample block as a reference, start with the sample block from -15° to 15° and fit it against the corresponding inner intersection line. Use grinding to remove any unfinished inner intersection line material. Use fine polishing to grind the 3D sample block against the corresponding intersection line area to achieve an overlap of more than 85%. Similarly, sequentially grind the adjacent sample blocks on both sides of the starting sample block from 15° to 45° (left), -45° to -15° (right); 45° to 75° (left), -75° to -45° (right); 75° to 110° (left), and -75° to -110° (right) to complete the corresponding parts of the grinding. Finally, smooth and polish the entire inner intersection line to complete the overall shaping and grinding.

[0011] Step 4: Design an inspection template according to the drawing requirements. Accurately mark the inner intersection lines according to the angle and position of the inspection template. Use the inspection template to re-inspect each area to confirm that it meets the drawing requirements.

[0012] Preferably, in step two, the effective cutting radius of the milling cutter is calculated to be less than 95mm based on the size of the selected milling cutter head. At the same time, a safety distance of 10mm is required to prevent interference and collision. The limit for machining the inner corner radius is 85mm, the maximum inner corner machining size is required to be 127mm, and at least 42mm of the root of the inner corner is not machined.

[0013] Preferably, in step three, the modeling process also includes collecting the linear curved surface of the intersecting line inside the finished branch pipe during modeling, and using milling to process it into the outer surface of the blank. The remaining parts are processed according to the drawings. Considering the integrity of the line, the two outermost sample blocks are designed at a 35° angle, and the remaining parts are divided at a 30° angle. The entire sample block is divided into 7 parts using wire cutting.

[0014] Preferably, in step three, during grinding, the sample blocks from the -15° to 15° section of the rectangular coordinate system are aligned with the corresponding positions to compare the linear surfaces that have been milled but whose surface roughness does not meet the requirements of the drawing, and the areas that have not been milled. The areas are marked, excess material is ground away, and the surface is polished until it meets the roughness requirements of the drawing.

[0015] Preferably, based on the above, when the fit reaches 85% or more, the grinding of the sample block area is completed. Similarly, the corresponding parts of the sample blocks adjacent to the starting sample block are ground in sequence. Finally, the entire body is polished to remove sharp corners and burrs, so that the transition of each area is smooth and the processing of the inner intersection line is completed.

[0016] Preferably, in step four, a sheet template is designed for inspection according to the dimensions of each part indicated on the drawing. The entire template includes all the arc lines of the corresponding position. Since one side of the inner intersection line transitions to the straight inner hole, while the other side transitions to the inner wall of the main pipe, the template on the other side is a hyperbola and cannot be positioned. To ensure that the template is correctly positioned, a straight edge section is left at the top of the template to fit against the inner wall of the straight inner hole. Except for the templates with arcs that are too small (90° and 105°), the rest are marked with a line at the midpoint of the arc of the template. The arc is symmetrical according to the line of the marked line as a reference.

[0017] Preferably, during the re-inspection in step four, the entire inner intersection line is first marked with lines according to the angle position indicated on the template, and the template is correctly positioned according to the corresponding position. The dimensional qualification is verified by the conformity between the template line shape at the corresponding position and the line shape of the processed inner intersection line.

[0018] The technical effects and advantages of this invention are as follows:

[0019] The line shape control of the intersecting line inside the large-radius branch pipe is accurately completed by a combination of milling and three-dimensional template grinding. The inspection template is designed according to the drawing acceptance standard for finished product inspection to ensure that the processing dimensions meet the drawing requirements. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the milling cutter structure of the present invention;

[0021] Figure 2 This is a diagram showing the correspondence between the mold angle distribution and the integrated pipe seat angle distribution of the present invention;

[0022] Figure 3 This is the front view of the three-dimensional sample block of the present invention;

[0023] Figure 4 This is a top view of the three-dimensional sample block of the present invention;

[0024] Figure 5 This is a front view of the inspection sample of the present invention;

[0025] Figure 6 This is a model diagram for processing according to the present invention.

[0026] The attached figures are labeled as follows: 1. Left sample block at 75°~110°; 2. Left sample block at 45°~75°; 3. Left sample block at 15°~45°; 4. Middle sample block at -15°~15°; 5. Right sample block at -45°~-15°; 6. Right sample block at -75°~-45°; 7. Right sample block at -75°~-110°. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] As attached Figure 1-6 The machining method for the inner intersection line of the large-radius variable-corner branch pipe shown uses UG software for modeling and its machining module for CNC programming. The inner hole diameter is φ366.520 -1.5 mm. The machining method includes the following steps: mm and hole depth 420mm.

[0029] Step 1: Modeling. Based on the finished drawing of the intersection line of the inner hole of the large fillet variable radius connector, only process the variable radius fillets within the intersection range of -110° to 110° in the inner hole of the integrated connector. Finally, determine the modeling style (model for processing). The chamfer adopts the variable radius edge chamfer. Input the corresponding radius values ​​R127, R115.3, R93.2, R65, R40.9, R24.6 and R15.2 at 0°, ±15°, ±30°, ±45°, ±60°, ±75° and ±90°.

[0030] Step 2: Enter the machining module of UG, use fixed contour milling, select a boring machine with a boring spindle diameter of φ110mm and a milling cutter head with a connecting part diameter of φ130mm and a maximum cutting outer diameter of φ320mm. Select standard milling cutters of Sangao models R335.25-315, 1721XL and 60-20L-R10, directly connect them to the end of the boring spindle, set a collision protection of 10mm for the inner hole, and at the same time reserve a 10mm safety distance to prevent interference and collision. Machining off the allowance within the range of approximately 85mm for the inner fillet radius, of which 42mm of allowance at the root of the inner fillet is not machined.

[0031] Step 3: Using the outer surface of the stainless steel 3D sample block as a reference, starting from the -15° to 15° center sample block 4, fit it against the corresponding inner intersection line. Use grinding to remove any unfinished inner intersection line material. Use fine polishing to make the 3D sample block fit against the corresponding intersection line area, so that the overlap reaches more than 85%. Similarly, sequentially complete the matching of the corresponding parts of the 15° to 45° left sample block 3, -45° to -15° right sample block 5; 45° to 75° left sample block 2, -75° to -45° right sample block 6; 75° to 110° left sample block 1, -75° to -110° right sample block 7 on both sides of the starting sample block. Then, smooth the overall transition and complete the overall shaping and polishing of all inner intersection lines.

[0032] Step 4: Design an inspection template according to the drawing requirements. Accurately mark the inner intersection lines according to the angle and position of the inspection template. Use the inspection template to re-inspect each area to confirm that it meets the drawing requirements.

[0033] In a specific embodiment, the effective cutting radius of the milling cutter is calculated to be less than 95mm based on the size of the selected milling cutter head. At the same time, a safety distance of 10mm is required to prevent interference and collision. The limit for machining the inner corner radius is 85mm, and the maximum inner corner machining size is required to be 127mm. At least 42mm of the root of the inner corner is not machined.

[0034] In a specific embodiment, step three also includes collecting the linear curved surface of the intersecting line inside the finished branch pipe during modeling, using milling to process the outer surface of the blank, and processing the remaining parts according to the drawings. Considering the integrity of the line, the two outermost sample blocks are designed at a 35° angle, and the remaining parts are divided at a 30° angle. The entire sample block is divided into 7 parts using wire cutting.

[0035] In a specific embodiment, during the grinding process in step three, the sample block 4, which is divided into -15° to 15° in the rectangular coordinate system, is attached to the corresponding position to compare the linear surface that has been milled but whose surface roughness does not meet the requirements of the drawing, and the areas that have not been milled. The areas are marked, excess material is ground away, and the surface is polished until it meets the roughness requirements of the drawing.

[0036] When the fit reaches 85% or more, the grinding of the sample block area is completed. Similarly, the corresponding parts of the sample blocks adjacent to the starting sample block are ground in sequence. Finally, the entire body is polished to remove sharp corners and burrs, so that the transition between each area is smooth and the processing of the inner intersection line is completed.

[0037] In a specific embodiment, in step four, a sheet template is designed for inspection based on the dimensions of each part indicated in the drawing. The entire template includes all the arc lines at the corresponding positions. Since one side of the inner intersection line transitions to the straight inner hole, while the other side transitions to the inner wall of the main pipe, the template on the other side is a hyperbola and cannot be positioned. To ensure the template is correctly positioned, a straight edge section is left at the top of the template to fit against the inner wall of the straight inner hole. Except for the templates with arcs that are too small (90° and 105°), all the others are marked with a line at the midpoint of the arc on the template. The arc is symmetrical according to the marked line as a reference.

[0038] During the re-inspection, the entire inner intersection line is first marked with lines according to the angle position indicated on the template. The template is then correctly positioned according to the corresponding position. The dimensional qualification is verified by the conformity between the template line shape at the corresponding position and the line shape of the processed inner intersection line.

[0039] The specific technical solution for machining the intersection line inside the large-rounded corner variable-radius branch pipe is as follows:

[0040] First, considering the internal hole machining diameter of φ366.520 -1.5 mm and the hole depth of 420 mm, a boring machine with a φ110 diameter boring spindle and a milling cutter with a φ320 diameter cutter head and a φ130 mm diameter cutter head at the connection point between the cutter head and the boring spindle end are selected. Here, the standard milling cutter model R335.25-315.1721XL.60-20L-R10 from Sanga is chosen. The milling cutter structure is shown in the appendix. Figure 1 Based on its installation dimensions, it can be directly connected to the end of the boring bar. It is modeled using UG and a variable radius chamfer is applied to the intersection line of the inner hole. The machining model is attached. Figure 6 The machining module uses a fixed-axis curved surface contour milling setting to configure the milling cutter size, cutting parameters, and toolpath parameters;

[0041] Based on the size of the selected milling cutter head, the effective cutting radius of the milling cutter must be less than 95mm. At the same time, a 10mm safety distance must be reserved to prevent interference and collision. The limit for machining the inner corner radius is 85mm. The maximum inner corner machining size needs to be 127mm. At least 42mm of the inner corner root must not be machined.

[0042] Due to strict tolerances, the subsequent line shape will be achieved using a template as a reference for grinding. Since the inner intersection line of the branch pipe and the main pipe is a hyperboloid, sheet templates cannot effectively control the line shape between templates. Therefore, a 3D template will be used for contour grinding. During modeling, the line shape surface of the inner intersection line of the finished branch pipe will be collected and milled into the outer surface of the blank. The remaining parts will be machined according to the drawings. A top view of the 3D template is attached. Figure 2 The main view of the 3D sample block is attached. Figure 3 ;

[0043] To ensure the integrity of the line shape, the two outermost sample blocks are designed at a 35° angle, and the remaining parts are divided at a 30° angle. The entire sample block is divided into 7 parts using wire cutting. Considering the frequent hand-held reference 3D sample block grinding, and to reduce weight, the 3D sample block is made of aluminum alloy. During grinding, the sample block 4 in the -15° to 15° range of the rectangular coordinate system is aligned with the corresponding position to compare the line shape surface that has been milled but whose surface roughness does not meet the drawing requirements, and the areas that have not been milled. The areas are marked, excess material is ground off, and the surface is polished until it meets the roughness requirements of the drawing.

[0044] When the fit reaches 85% or more, the grinding of the sample block area is completed. Similarly, the two sample blocks adjacent to the starting sample block are ground in sequence to complete the corresponding parts. Finally, the whole body is polished to remove sharp corners and burrs, so that the transition of each area is smooth and the processing of the inner intersection line is completed.

[0045] Design sheet-like templates for inspection based on the dimensions of each part indicated on the drawings. See the attached main view of the inspection template. Figure 4 The entire template includes all the arc lines at the corresponding positions. Since one side of the inner intersection line transitions to the straight inner hole, while the other side transitions to the inner wall of the main pipe, the template cannot be positioned due to the hyperbolic shape of this side. To ensure the template is correctly positioned, a straight edge section is left at the top of the template to fit against the inner wall of the straight inner hole. Except for templates with arcs that are too small (90° and 105°), all other templates have marking lines at the midpoint of the arcs. The marking lines are used as a reference to ensure that the arcs are symmetrical according to the marking lines. During the final inspection, the entire inner intersection line is first drawn according to the angle position marked on the template. The template is then correctly positioned according to the corresponding position. The dimensional qualification is verified by the match between the template line at the corresponding position and the line of the processed inner intersection line.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for machining the intersection line inside a branch pipe with a large fillet and variable radius, using UG software for modeling and its machining module for CNC programming, characterized by: Includes the following steps: Step 1: Modeling. Based on the finished drawing of the intersection line of the inner hole of the large fillet variable radius connector, only process the variable radius fillets within the -110° to 110° range of the inner hole of the integrated connector. Finally, determine the modeling style. The chamfer adopts the variable radius edge chamfer. Input the corresponding radius values ​​R127, R115.3, R93.2, R65, R40.9, R24.6 and R15.2 at 0°, ±15°, ±30°, ±45°, ±60°, ±75° and ±90°. Step 2: Enter the machining module of UG, use fixed contour milling, select a boring machine with a boring spindle diameter of φ110mm and a milling cutter head with a connecting part diameter of φ130mm and a maximum cutting outer diameter of φ320mm. Select standard milling cutters of Sangao models R335.25-315, 1721XL and 60-20L-R10, directly connect them to the end of the boring spindle, set a collision protection of 10mm for the inner hole, and at the same time reserve a 10mm safety distance to prevent interference and collision. Machining off the allowance within the range of approximately 85mm for the inner fillet radius, of which 42mm of allowance at the root of the inner fillet is not machined. Step 3: Using the outer edge of the three-dimensional sample block as a reference, start from the -15° to 15° middle sample block (4) and fit it with the corresponding inner intersection line. Use grinding to remove the unprocessed inner intersection line material. Use grinding and polishing to fit the three-dimensional sample block with the corresponding intersection line area and grind it so that the overlap reaches more than 85%. Similarly, sequentially put the 15° to 45° left sample block (3), -45° to -15° right sample block (5), 45° to 75° left sample block (2), -75° to -45° right sample block (6), 75° to 110° left sample block (1), and -75° to -110° right sample block (7) on both sides of the starting sample block to complete the corresponding parts of the grinding and matching. Then, smooth and polish the entire inner intersection line to complete the overall shaping and grinding. Step 4: Design an inspection template according to the drawing requirements. Accurately mark the inner intersection lines according to the angle and position of the inspection template. Use the inspection template to re-inspect each area to confirm that it meets the drawing requirements.

2. The method for machining the intersecting line inside a large-rounded corner variable-radius branch pipe according to claim 1, characterized in that: In step two, based on the size of the selected milling cutter head, the effective cutting radius of the milling cutter is calculated to be less than 95mm. At the same time, a safety distance of 10mm is required to prevent interference and collision. The limit for machining the inner corner radius is 85mm, and the maximum inner corner machining size is required to be 127mm. At least 42mm of the inner corner root must not be machined.

3. The method for machining the intersecting line inside a large-rounded corner variable-radius branch pipe according to claim 1, characterized in that: Step three also includes collecting the linear curved surface of the intersecting line inside the finished branch pipe during modeling, using milling to process the outer surface of the blank, and processing the remaining parts according to the drawings. Considering the integrity of the line, the two outermost sample blocks are designed at a 35° angle, and the remaining parts are divided at a 30° angle. The entire sample block is divided into 7 parts using wire cutting.

4. The method for machining the intersecting line inside a large-rounded corner variable-radius branch pipe according to claim 1, characterized in that: The three-dimensional sample is made of stainless steel.

5. The method for machining the intersecting line inside a large-rounded corner variable-radius branch pipe according to claim 1, characterized in that: In step three, during grinding, the sample block (4) of the -15° to 15° center of the rectangular coordinate system is first attached to the corresponding position to compare the linear surface that has been milled but whose surface roughness does not meet the requirements of the drawing, and the area that has not been milled. The area is marked, excess material is ground off and polished until the surface meets the roughness requirements of the drawing.

6. The method for machining the intersecting line inside a large-radius variable-round-corner branch pipe according to claim 5, characterized in that: Based on the above, when the fit reaches 85% or more, the grinding of the sample block area is completed. Similarly, the corresponding parts of the sample blocks adjacent to the starting sample block are ground in sequence. Finally, the entire body is polished to remove sharp corners and burrs, so that the transition of each area is smooth and the processing of the inner intersection line is completed.

7. The method for machining the intersecting line inside a large-rounded corner variable-radius branch pipe according to claim 1, characterized in that: In step four, a sheet template is designed for inspection based on the dimensions of each part indicated on the drawing. The entire template includes all the arc lines of the corresponding position. Since one side of the inner intersection line transitions to the straight inner hole, while the other side transitions to the inner wall of the main pipe, the template on the hyperbola side cannot be positioned. To ensure the template is correctly positioned, a straight edge section is left at the top of the template to fit against the inner wall of the straight inner hole. Except for the templates with arcs that are too small (90° and 105°), a marking line is made at the midpoint of the arc of the template. The marking line is used as a reference to ensure that the arc is symmetrical according to the marking line.

8. The method for machining the intersecting line inside a large-rounded corner variable-radius branch pipe according to claim 1, characterized in that: In step four, during the re-inspection, the entire inner intersection line is first marked with lines according to the angle position indicated on the template. The template is then correctly positioned according to the corresponding position. The dimensional qualification is verified by the conformity between the template line shape at the corresponding position and the line shape of the processed inner intersection line.

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