3D additive round-to-square structure machining tool and machining method thereof

Abstract

The invention discloses a 3D additive round-to-square structure machining tool and a machining method thereof, and relates to the technical field of 3D additive thin-wall part machining, in particular to the 3D additive round-to-square structure machining tool and the machining method thereof, which have the advantages that in the aspect of the tool, an adjusting seat can flexibly adapt to structures with different specifications and deformation, and stable and accurate clamping is ensured; the smooth clamping seat protects the surface of the structure and enables the clamping force to be uniform; the internal support prevents deformation, and the machining quality is improved; and the fixed clamping groove is matched with the rod, and the length adjusting mechanism realizes quick mounting and flexible supporting. According to the machining method, errors can be eliminated, stress can be released, precise machining can be achieved, the product size and shape precision can be guaranteed, the product reliability, universality and machining efficiency can be improved, and the product quality and performance can be comprehensively improved through the links of filling, scanning comparison, multiple times of calibration detection, heat treatment, retesting and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D additive thin-walled parts processing, and in particular to a 3D additive round-to-square structure processing tool and a processing method thereof. Background Art

[0002] As the demand for lightweight structures in the aerospace field surges, 3D additively manufactured titanium alloy round-to-square structures (such as engine transition sections and fuel pipeline adapters) have become key load-bearing components due to their complex inner cavities, thin walls (wall thickness ≤ 2mm), and large aspect ratios (≥10:1). However, existing processing technologies have three major bottlenecks: Failure of tooling support: Traditional rigid supports have only single-point contact, and local stress concentration is prone to occur in thin-walled areas (measured stress ≥ 80MPa), resulting in processing chatter (amplitude > 0.05mm) and dimensional deviation (roundness error > 0.15mm); Lack of deformation control: The original residual stress of 3D printing (peak value up to 250MPa) is superimposed on the machining stress, and the springback after heat treatment reaches 0.3-0.5mm, far exceeding the aviation standard (≤0.1mm); Low calibration efficiency: relying on manual leveling, single-piece leveling takes more than 2 hours, and thin-walled structures are prone to plastic deformation (deformation > 0.08mm) due to multiple clamping. Summary of the invention

[0003] The present invention aims to overcome the above-mentioned disadvantages of the prior art and provide a complete set of long fine hole machining machine tools and a machining method thereof.

[0004] The technical solution adopted by the present invention is as follows: A 3D additive round-to-square structure processing tool, comprising: a clamping base for clamping and fixing the round-to-square structure, the clamping base comprising an adjustment seat and a clamping seat, the adjustment seat comprising a plurality of seats, and the height of the seats can be adjusted; the clamping seat is arranged on the adjustment seat, and the side on which the round-to-square structure is placed is a smooth plane; It also includes an internal support for supporting the inside of the round-to-square structure when the outside of the round-to-square structure is processed, and the support surface of the internal support matches the inside of the round-to-square structure.

[0005] Furthermore, the adjustment seats include four, which are arranged opposite to each other in pairs, and are used to adjust the height of the four directions of the round-to-square structure.

[0006] Furthermore, the internal supports include multiple ones, which are evenly arranged in an array on the inner wall of the round-to-square structure.

[0007] Furthermore, a fixing slot is provided on a side of the internal support opposite to the supporting surface, and also includes a fixing rod, the end of the fixing rod matches the size of the fixing slot.

[0008] Furthermore, the fixing rod is provided with a length adjustment mechanism.

[0009] Furthermore, a 3D additive round-to-square structure processing tool comprises the following steps: S1: Place the printed bottom surface of the 3D additively printed round-to-square structure on the clamping seat, and add fillers to fill the gap between the placement surface of the round-to-square structure and the clamping seat; S2: Blue light scanning: Scan the blank as a whole to form actual blank data and establish a three-dimensional model; S3: Use the adjustment seat to initially level the top opening; S4: Compare the round-to-square structure blank model with the standard model, obtain the 3D printing deformation after comparison, and find the first cutting top surface reference; S5: Press the parts, re-measure the points and then mill the top surface of the parts flat; S6: Turn over and clamp, use a feeler gauge to check whether the gap between the bottom surface and the tooling fitting surface meets the standard in a free state, and check whether the point position obtained in step S2 is consistent with the table re-inspection; S7: Roughen the whole part, remove the printed oxide layer, polish the surface of the part, and leave allowance for subsequent processing; S8: Vacuum heat treatment is used to release the internal stress caused by rough machining and the stress of the original blank; S9: Perform ultrasonic flaw detection on the parts, and then perform a second blue light scan to obtain a rough-processed data model; S10: According to the comparison model obtained in step S9, the interior of the part is finely processed; S11: Use internal supports to support the inside of the part, and fix the internal supports with fixing rods, and then finish machining the outer surface of the part; S12: Remeasure the part size and adjust the error size until the size meets the standard requirements.

[0010] Furthermore, the filler selected in step S1 is a mixture of rubber particles and glue, the rubber particles have a particle size of 0.5-1 mm, the glue is epoxy resin glue, and the mixture is carried out at a volume ratio of rubber particles: glue = 3:1. The filling is carried out in layers and compacted, and the thickness of each layer does not exceed 5 mm.

[0011] Furthermore, when the adjustment seat is used to initially level the top opening in step S3, a laser level is used to assist in the adjustment. The accuracy of the laser level is ±0.005 mm. During the adjustment process, the levelness of each point of the top opening is monitored in real time to ensure that the adjustment accuracy is controlled within ±0.02 mm.

[0012] Furthermore, the specific process of vacuum heat treatment in step S8 is: put the parts into a vacuum heat treatment furnace, first evacuate the furnace to below 1×10⁻³Pa, then heat it to 600-650℃, keep it warm for 2-3 hours, and then cool it down to below 100℃ at a cooling rate of 3-5℃ / min before taking it out of the furnace. During the whole heat treatment process, the temperature fluctuation range in the furnace is controlled within ±5℃.

[0013] Furthermore, in step S12, CNC measurement re-measurement is adopted: a three-coordinate measuring machine is used to measure the parts, and the flatness, hole position and shape profile are all qualified and meet the requirements.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: The design of multiple adjustable height adjustment seats enables the tooling to adapt to various specifications and shapes of 3D additive round-to-square structures. By adjusting the seat to accurately adjust the height of the round-to-square structure in four directions, the horizontality and stability of the structure can be effectively guaranteed during clamping. This height-adjustable design can avoid processing errors caused by improper clamping, making the subsequent processing benchmark more accurate, laying a solid foundation for improving processing accuracy.

[0015] The support surface of the internal support matches the inside of the round-to-square structure, and can provide reliable support for the inside when processing the outside of the round-to-square structure. For thin-walled round-to-square structures, they are easily deformed by cutting forces during external processing. The internal support can effectively resist this deformation force, ensure the shape accuracy of the structure during processing, and improve the product qualification rate.

[0016] During the processing, calibration and testing are carried out many times, such as using the adjustment seat to level the top opening, re-testing the points, ultrasonic flaw detection, and the second blue light scan, etc., so that errors that occur during the processing can be discovered and corrected in time. Each calibration and test is a guarantee of processing accuracy. Through continuous adjustment and optimization, it is ensured that the size accuracy and shape accuracy of the final processed round-to-square structure meet the design requirements.

[0017] Multiple calibrations and tests can comprehensively monitor and evaluate product quality, and timely discover potential quality problems, such as internal defects, stress concentration, etc. Problems found can be dealt with in a timely manner to prevent unqualified products from flowing into the next process, thereby improving product reliability and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the clamping structure of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention after flipping and clamping; Figure 3It is a schematic diagram of the structure of the external processing of the present invention; Figure 4 It is a structural schematic diagram of the clamping base of the present invention; Figure 5 It is a schematic diagram of the structure of the internal support of the present invention; Figure 6 It is a structural schematic diagram of the fixing rod of the present invention.

[0019] Markings in the figure: 1- clamping base, 2- clamping seat, 3- adjustment seat, 4- internal support, 5- fixing slot, 6- fixing rod. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] Embodiment 1 In this embodiment, if Figure 1 , 2 As shown, a 3D additive round-to-square structure processing tool comprises: a clamping base for clamping and fixing the round-to-square structure, the clamping base comprises an adjustment seat and a clamping seat, the adjustment seat comprises a plurality of seats, and the height of the adjustment seat can be adjusted; the clamping seat is arranged on the adjustment seat, and the side on which the round-to-square structure is placed is a smooth plane; It also includes an internal support for supporting the inside of the round-to-square structure when the outside of the round-to-square structure is processed, and the support surface of the internal support matches the inside of the round-to-square structure.

[0023] Adjustment seat: The screw nut pair is used as the height adjustment mechanism, and the screw accuracy reaches ±0.01mm. This high-precision adjustment mechanism can ensure the precise adjustment of the height of the round-to-square structure, providing an accurate benchmark for subsequent processing. For example, when processing a round-to-square transition section for a large aircraft engine, the height error of the structure during the processing is controlled within a very small range through the precise adjustment of the adjustment seat, which effectively improves the accuracy of subsequent processing.

[0024] Clamping seat: 45# steel is selected and tempered before grinding, and the flatness is controlled at ±0.005mm. This smooth and high-precision plane can fit well with the bottom surface of the round-to-square structure, reducing the gap and error during the clamping process and ensuring the stability of the clamping. For example, when processing some thin-walled round-to-square structures, a good fitting surface can effectively prevent the structure from shaking and deforming during the processing.

[0025] Internal support: The support surface of the internal support is customized according to the internal shape of the round-to-square structure, manufactured using 3D printing technology, and the material is selected from high-strength, low-elastic modulus aluminum alloy to ensure that it can provide sufficient support while avoiding damage to the interior of the structure. In practical applications, for some round-to-square structures with complex internal shapes, customized internal supports can fit well to their inner walls and provide reliable support for external processing.

[0026] Further, such as Figure 4 As shown, the adjustment seats include four, which are arranged opposite to each other in pairs and are used to adjust the height of the four directions of the round-to-square structure.

[0027] Arrangement: There are 4 adjustment seats, arranged opposite to each other. Each adjustment seat is independently controlled and can accurately adjust the height of the four positions of the round-to-square structure.

[0028] Actual effect: When processing a large round-to-square structure with a length of 1000mm and a width of 800mm, the top opening of the structure tilted due to the unevenness that may exist in the 3D printing process. By independently adjusting the height of the four adjustment seats and using a laser level (accuracy of ±0.005mm) for real-time monitoring, the level of the top opening can be quickly and accurately adjusted to within ±0.02mm, providing an accurate benchmark for subsequent milling processing and greatly improving processing accuracy.

[0029] Further, such as Figure 3 As shown, the internal supports include multiple ones, which are evenly arranged in an array on the inner wall of the round-to-square structure.

[0030] The internal supports are arranged on the inner wall of the round-to-square structure in a uniform array. For example, for a round-to-square structure with an inner diameter of 500 mm, an internal support is arranged every 60° in the circumferential direction.

[0031] Actual effect: When the structure is subjected to external finishing, the uniform array of internal supports can evenly disperse the stress generated during the machining process, effectively preventing the structure from deforming and greatly improving the machining quality.

[0032] Further, such as Figure 5 , 6 As shown, a fixing slot is provided on the side of the internal support opposite to the support surface, and also includes a fixing rod, the end of the fixing rod matches the size of the fixing slot.

[0033] A T-shaped fixing slot is set on the side of the internal support opposite to the support surface, and the end of the fixing rod is designed as a matching T-shaped structure with a dimensional tolerance of ±0.01mm. This precise fit ensures a tight and reliable connection between the fixing rod and the internal support.

[0034] Practical application: When processing a round-to-square structure with high precision requirements, the internal support can be quickly fixed to the inner wall of the round-to-square structure by inserting the fixing rod into the fixing slot of the internal support. In the subsequent processing, even if it is subjected to a large cutting force, the internal support will not loosen or move, ensuring the stability and precision of the processing.

[0035] Furthermore, the fixing rod is provided with a length adjustment mechanism.

[0036] The fixed rod adopts an electric telescopic rod as a length adjustment mechanism, and the motor drives the screw nut pair to achieve precise length adjustment.

[0037] Actual effect: When processing round-to-square structures of different specifications, the length of the fixing rod can be quickly adjusted according to the actual size of the structure. For example, when processing a round-to-square structure with a large range of inner diameter changes, by adjusting the length of the fixing rod, the internal support can always fit closely to the inner wall of the structure, providing reliable support for processing. At the same time, the precise length adjustment function also ensures that the support force of the internal support is evenly distributed during the processing, further improving the processing accuracy.

[0038] Embodiment 2 A 3D additive round-to-square structure processing tool comprises the following steps: S1: Place the printed bottom surface of the 3D additively printed round-to-square structure on the clamping seat, and add fillers to fill the gap between the placement surface of the round-to-square structure and the clamping seat. The filler is a material mixed with rubber particles and epoxy resin glue in a volume ratio of 3:1. The filling is layered and compacted, and the thickness of each layer does not exceed 5mm. This filling method can ensure a close fit between the structure and the clamping seat and reduce clamping errors.

[0039] S2: Use a high-precision blue light scanner to scan the blank as a whole, with a scanning accuracy of ±0.01mm, to form actual blank data and build a three-dimensional model. The model can accurately reflect the actual shape and size of the blank, providing an accurate reference for subsequent processing.

[0040] S3: Use the adjustment seat to initially level the top opening, and use a laser level (accuracy of ±0.005mm) to assist in the adjustment. During the adjustment process, monitor the levelness of each point of the top opening in real time to ensure that the adjustment accuracy is controlled within ±0.02mm.

[0041] S4: Compare the round-to-square structure blank model with the standard model with high precision, obtain the 3D printing deformation after comparison, and find the first cutting top surface reference.

[0042] S5: Use hydraulic clamping device to clamp the parts, control the clamping force within the appropriate range, and mill the top surface reference of the parts after re-measuring the points.

[0043] S6: Turn over and clamp, use a feeler gauge to check the gap between the bottom surface and the tooling fitting surface in a free state, the gap is controlled within ±0.02mm and meets the standard, and the consistency between the point position obtained in step S2 reaches ±0.01mm.

[0044] S7: The whole part is roughed, and a carbide end mill is used. The tool diameter is reasonably selected according to the size of the round-to-square structure. Coolant is used for cooling and lubrication during the roughing process. The coolant is a water-soluble cutting fluid. Remove the printed oxide layer and polish the surface of the part, leaving a 3mm allowance for subsequent processing.

[0045] S8: Vacuum heat treatment is used to release the machined internal stress generated by rough machining and the stress of the original blank. The parts are placed in a vacuum heat treatment furnace. The furnace is first evacuated to below 1×10⁻³Pa, then the temperature is raised to 600-650℃, kept at this temperature for 2-3 hours, and then cooled to below 100℃ at a cooling rate of 3-5℃ / min. During the entire heat treatment process, the temperature fluctuation range in the furnace is controlled within ±5℃.

[0046] S9: Perform ultrasonic flaw detection on the parts, and the flaw detection sensitivity reaches the specified standard. After the flaw detection, a second blue light scan is performed to obtain the data model after rough processing.

[0047] S10: According to the comparison model obtained in step S9, the interior of the part is finely processed, and the processing accuracy reaches ±0.005mm.

[0048] S11: Use internal supports to support the inside of the part, and fix the internal supports with fixing rods. After fixing, fine-machine the outer surface of the part with a machining accuracy of ±0.005mm.

[0049] S12: Use a three-coordinate measuring machine to measure parts, remeasure part dimensions, and adjust error dimensions until the flatness, hole position, and shape profile meet the requirements, and the dimensional error is controlled within ±0.002mm.

[0050] Furthermore, the filler selected in step S1 is a mixture of rubber particles with certain elasticity and strength and glue, the rubber particles have a particle size of 0.5-1mm, the glue is epoxy resin glue, and the mixture is carried out at a volume ratio of rubber particles: glue = 3:1. The filling is carried out in layers and compacted, and the thickness of each layer does not exceed 5mm.

[0051] Rubber particles with a particle size of 0.5-1mm are selected and mixed with epoxy resin glue at a volume ratio of 3:1. Rubber particles have a certain elasticity and can buffer the vibration and impact during processing; epoxy resin glue has good adhesion and strength, and can firmly bond the rubber particles together to form an integral filling layer.

[0052] Filling method: Layered filling and compaction are adopted, and the thickness of each layer does not exceed 5mm. This filling method can ensure that the filler fully fills the gap and has a higher density and strength after compaction. For example, when processing a thin-walled round-to-square structure, after adopting this filling method, the structure is more stable during clamping and processing, and the possibility of deformation is reduced.

[0053] Furthermore, when the adjustment seat is used to initially level the top opening in step S3, a laser level is used to assist in the adjustment. The accuracy of the laser level is ±0.005 mm. During the adjustment process, the levelness of each point of the top opening is monitored in real time to ensure that the adjustment accuracy is controlled within ±0.02 mm.

[0054] When using the adjustment seat to initially level the top opening, place the laser level in a suitable position so that it can illuminate the key points of the top opening. During the adjustment process, read the level data displayed by the laser level in real time and adjust the height of the adjustment seat according to the data. For example, when the laser level shows that the level deviation of a certain point is 0.03mm, adjust the corresponding height of the adjustment seat to gradually make the level of the point approach zero deviation.

[0055] Actual effect: By using a laser level to assist in adjustment, the adjustment accuracy can be controlled within ±0.02mm, greatly improving the accuracy and efficiency of adjustment. Compared with the traditional manual visual observation and adjustment method, it not only reduces the adjustment time, but also improves the adjustment accuracy, providing a better benchmark for subsequent processing.

[0056] Furthermore, the specific process of vacuum heat treatment in step S8 is: put the parts into a vacuum heat treatment furnace, first evacuate the furnace to below 1×10⁻³Pa, then heat it to 600-650℃, keep it warm for 2-3 hours, and then cool it down to below 100℃ at a cooling rate of 3-5℃ / min before taking it out of the furnace. During the whole heat treatment process, the temperature fluctuation range in the furnace is controlled within ±5℃.

[0057] After vacuum heat treatment, residual stress detection was performed on the parts, and it was found that the internal stress caused by rough machining and the stress of the original blank were effectively released, and the residual stress was reduced by more than 80%. In the subsequent finishing process, the deformation of the parts was significantly reduced and the processing accuracy was significantly improved.

[0058] Furthermore, in step S12, CNC measurement re-measurement is adopted: a three-coordinate measuring machine is used to measure the parts, and the flatness, hole position and shape profile are all qualified and meet the requirements.

[0059] The machined parts are placed on the workbench of the three-dimensional coordinate measuring machine, and the measuring software controls the measuring probe to measure the key dimensions of the parts, such as flatness, hole position, and contour. During the measurement process, the measuring probe automatically moves along the preset path to collect a large amount of measurement data.

[0060] Practical significance: Through the high-precision measurement of the three-dimensional coordinate measuring machine, the dimensional error of the parts can be accurately detected. According to the measurement results, the error size is adjusted until the flatness, hole position and shape profile meet the requirements and the dimensional error is controlled within ±0.002mm. This precise measurement and adjustment process can ensure that the final quality of the parts meets the design requirements and improve the product qualification rate and reliability.

[0061] The above description is only a preferred embodiment of the invention and is not intended to limit the invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the invention should be included in the protection scope of the invention.

Claims

1. A 3D additive round-to-square structure processing tool, characterized by: include: A clamping base for clamping and fixing the round-to-square structure, the clamping base includes an adjustment seat and a clamping seat, the adjustment seat includes a plurality of seats, and the height of the seats can be adjusted; the clamping seat is arranged on the upper part of the adjustment seat, and the side on which the round-to-square structure is placed is a smooth plane; It also includes an internal support for supporting the inside of the round-to-square structure when the outside of the round-to-square structure is processed, and the support surface of the internal support matches the inside of the round-to-square structure.

2. A 3D additive manufacturing tool for turning a round into a square structure according to claim 1, characterized in that: The adjustment seats include four, which are arranged opposite to each other in pairs and are used to adjust the height of the four positions of the round-to-square structure.

3. A 3D additive round-to-square structure processing tool according to claim 1, characterized in that: The internal supports include a plurality of supports which are evenly arranged in an array on the inner wall of the round-to-square structure.

4. A 3D additive manufacturing tool for turning a round into a square structure according to claim 3, characterized in that: The inner support is provided with a fixing slot on one side opposite to the supporting surface, and also comprises a fixing rod, the end of the fixing rod matches the size of the fixing slot.

5. A 3D additive manufacturing tool for turning a round into a square structure according to claim 4, characterized in that: The fixing rod is provided with a length adjustment mechanism.

6. A 3D additive round-to-square structure processing method, applied to a 3D additive round-to-square structure processing tool as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Place the printed bottom surface of the 3D additively printed round-to-square structure on the clamping seat, and add fillers to fill the gap between the placement surface of the round-to-square structure and the clamping seat; S2: Blue light scanning: Scan the blank as a whole to form actual blank data and establish a three-dimensional model; S3: Use the adjustment seat to initially level the top opening; S4: Compare the round-to-square structure blank model with the standard model, obtain the 3D printing deformation after comparison, and find the first cutting top surface reference; S5: Press the parts, re-measure the points and then mill the top surface of the parts flat; S6: Turn over and clamp, use a feeler gauge to check whether the gap between the bottom surface and the tooling fitting surface meets the standard in a free state, and check whether the point position obtained in step S2 is consistent with the table re-inspection; S7: Roughen the whole part, remove the printed oxide layer, polish the surface of the part, and leave allowance for subsequent processing; S8: Vacuum heat treatment is used to release the internal stress caused by rough machining and the stress of the original blank; S9: Perform ultrasonic flaw detection on the parts, and then perform a second blue light scan to obtain a rough-processed data model; S10: According to the comparison model obtained in step S9, the interior of the part is finely processed; S11: Use internal supports to support the inside of the part, and fix the internal supports with fixing rods, and then finish machining the outer surface of the part; S12: Remeasure the part size and adjust the error size until the size meets the standard requirements.

7. A 3D additive manufacturing method for a round-to-square structure according to claim 6, characterized in that: The filler selected in step S1 is a mixture of rubber particles and glue, the rubber particles have a particle size of 0.5-1 mm, and the glue is epoxy resin glue, which are mixed at a volume ratio of rubber particles: glue = 3:

1. The filling is carried out in layers and compacted, and the thickness of each layer does not exceed 5 mm.

8. A 3D additive manufacturing method for a round-to-square structure according to claim 6, characterized in that: When the adjustment seat is used to initially level the top opening in step S3, a laser level is used to assist in the adjustment. The accuracy of the laser level is ±0.005 mm. During the adjustment process, the levelness of each point of the top opening is monitored in real time to ensure that the adjustment accuracy is controlled within ±0.02 mm.

9. A 3D additive manufacturing method for a round-to-square structure according to claim 6, characterized in that: The specific process of vacuum heat treatment in step S8 is: put the parts into a vacuum heat treatment furnace, first evacuate the furnace to below 1×10⁻³Pa, then heat it to 600-650℃, keep it warm for 2-3 hours, and then cool it down to below 100℃ at a cooling rate of 3-5℃ / min before taking it out of the furnace. During the whole heat treatment process, the temperature fluctuation range in the furnace is controlled within ±5℃.

10. A method for processing a 3D additively manufactured round-to-square structure according to claim 6, characterized in that: In step S12, CNC measurement re-measurement is adopted: a three-coordinate measuring machine is used to measure the parts, and the flatness, hole position and shape profile are all qualified and meet the requirements.

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