Power iron accessory hole group drilling, tapping and chamfering integrated machining process
By integrating visual inspection and multi-axis machining head processing technology, high-precision and automated processing of hole positions for electric railway accessories has been achieved, solving the problems of low hole position accuracy and low production efficiency in existing technologies, and improving processing quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG HAICHUAN ELECTRIC POWER EQUIP CO LTD
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-29
AI Technical Summary
The existing hole processing technology for electric railway accessories has problems such as difficulty in ensuring the relative positional accuracy of the holes, large equipment footprint due to multiple independent processing steps, high labor costs, and low production efficiency.
The system employs a vision inspection component for 3D topographic scanning. A multi-axis machining head carries a drilling assembly, a tapping assembly, and a chamfering assembly, enabling integrated processing of the three processes of drilling, tapping, and chamfering. Combined with technologies such as load current detection, axial force sensor, and elastic polishing sleeve, it achieves automated control and high-precision machining.
It improves the positional accuracy of hole machining, eliminates positioning errors introduced by repeated clamping, ensures the high degree of coincidence between the drilling center, tapping center, and chamfering center, improves thread quality and chamfer concentricity, shortens the machining process, and increases production efficiency and yield.
Smart Images
Figure CN122099751A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power fittings processing technology, specifically to an integrated processing technology for drilling, tapping, and chamfering holes in power iron accessories. Background Technology
[0002] Power line accessories are key metal components used to connect and fix conductors, insulators and other components in transmission line towers and substation structures. They mainly include products such as crossarm angle steel, connecting plates and clamps. These components usually need to be machined with multiple connecting holes, threaded holes and chamfers in different positions to meet the requirements of on-site assembly and connection.
[0003] Current machining processes for holes in power railway accessories typically employ a step-by-step, independent machining method. This involves first drilling, then transferring the workpiece to a tapping machine for tapping, and finally transferring it to a chamfering machine for chamfering the hole opening. This step-by-step method presents the following technical problems: Transferring the workpiece between different machines requires multiple repeated clamping and positioning, each introducing positioning errors and making it difficult to guarantee the relative positional accuracy of the holes; the lack of coordinated control between the various processes during step-by-step machining makes it easy for the center position of the drilled hole to deviate from the center position of subsequent tapping and chamfering, affecting thread quality and chamfer concentricity; multi-process independent machining requires multiple machines and numerous operators, resulting in large equipment footprints, high labor costs, and low production efficiency; for large-batch production tasks of power railway accessories, the step-by-step machining method cannot meet the cycle time requirements of large-scale production. Summary of the Invention
[0004] The purpose of this invention is to provide an integrated machining process for drilling, tapping, and chamfering holes in power railway accessories, so as to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution: an integrated machining process for drilling, tapping, and chamfering holes in power railway accessories, comprising the following steps: S1. The blank of the electric iron accessory to be processed is clamped and fixed in the processing station, and the blank is initially positioned. S2. Project coded structured light onto the blank surface through the vision detection component, acquire the structured light modulation image of the blank surface, and reconstruct the three-dimensional morphology data of the blank surface based on the structured light modulation image. S3. Retrieve the standard hole position distribution model from the storage unit, and perform spatial position fitting between the physical feature points in the three-dimensional topography data and the virtual feature points in the standard hole position distribution model to determine the actual processing coordinates of each hole position to be processed. S4. Drive the multi-axis machining head to the first machining position according to the actual machining coordinates; S5. Control the feed of the multi-axis drilling assembly mounted on the multi-axis machining head to simultaneously drill multiple holes in the blank. S6. After drilling is completed, drive the multi-axis machining head to switch to the tapping assembly and move to the second machining position to simultaneously tap multiple drilled holes. S7. After tapping is completed, drive the multi-axis machining head to switch to the chamfering assembly and move to the third machining position to simultaneously chamfer the edges of each hole. S8. The dimensions of the finished holes are inspected by the detection component, and the blanks are sorted and output according to the inspection results.
[0006] As a preferred embodiment of the present invention, the specific process steps for projecting coded structured light in step S2 include: A low-density grating is used to perform a coarse scan of the overall outline of the blank, and to identify the edge outline and main feature areas of the blank. Based on the main feature regions identified by the coarse scan, the grating density and projection angle of the projection unit are adjusted to perform a high-density grating fine scan on the identified main feature regions. The overall contour data obtained by coarse scanning and the local feature data obtained by fine scanning are spatially fused to generate complete three-dimensional topographic data of the blank surface.
[0007] As a preferred embodiment of the present invention, the specific process steps for spatial position fitting in step S3 include: Extract the actual spatial locations of at least three positioning reference holes or positioning reference surfaces from the complete three-dimensional topography data; The extracted actual spatial points are rigidly registered with the corresponding theoretical reference points in the standard hole distribution model to minimize the total spatial distance deviation between the actual spatial points and the theoretical reference points. After rigid registration is completed, the starting guide points of each hole to be processed are generated by mapping the theoretical coordinates of each hole in the standard hole distribution model into the three-dimensional shape data of the blank.
[0008] As a preferred embodiment of the present invention, after generating the initial guide point, the process further includes a step of verifying the guide point point by point: The multi-axis machining head is driven to move the point laser probe to each guide point. The point laser probe emits a laser beam perpendicularly to the surface of the blank and collects the actual surface reflection intensity value and the actual surface height value at each guide point. The actual surface reflection intensity value is compared with the standard reflection intensity threshold. When the reflection intensity value is lower than the standard reflection intensity threshold, it is determined that the guide point is located in the concave or edge area of the blank surface, and automatically shifts to a preset distance away from the concave or edge area to generate a corrected processing starting point.
[0009] As a preferred embodiment of the present invention, the specific process steps of drilling in step S5 include: The control group drill assembly is idling and approaching the blank surface at a first rotation speed and a first feed speed. When the drill tip of the group drill assembly contacts the blank surface, the load current change of the spindle drive motor is detected. When the load current is detected to rise to the first current threshold, it is determined that the drill tip has cut into the surface of the blank, and then the group drill assembly is controlled to switch to the second rotation speed and the second feed speed for stable drilling. When the drilling depth reaches the preset hole depth, the control group drilling assembly automatically reduces the feed speed to the third feed speed until the preset hole depth is reached, thus completing the drilling process.
[0010] As a preferred embodiment of the present invention, the in-hole chip removal process is performed simultaneously during the drilling process: While the drilling assembly is feeding, a high-pressure pulsed airflow is intermittently injected into the axial through hole inside the drill bit through a pulsed airflow generator connected to the tail of the drilling assembly. The high-pressure pulsed airflow is ejected from the chip removal hole at the drill tip, blowing the chips generated by drilling out of the hole in the opposite direction along the spiral groove outside the drill bit. The frequency of pulsed airflow is synchronized with the rotational speed of the drill bit, with one pulsed airflow injected for each revolution of the drill bit.
[0011] As a preferred embodiment of the present invention, the specific process steps of tapping in step S6 include: Control the tapping assembly to rotate forward at the fourth rotation speed and feed rapidly to a preset distance above the hole opening; Switch to the fifth speed for slow feed, so that the tap guide enters the borehole; Once the tap is fully inserted into the hole, the tapping assembly is controlled to tap at the sixth rotation speed, while the axial force sensor installed at the tail of the tapping assembly monitors the tapping axial force in real time. When the axial force exceeds the preset force threshold, the tapping assembly is controlled to pause the feed and keep rotating until the axial force drops below the preset force threshold, then the feed is resumed to continue tapping. After tapping to the preset depth, control the tapping assembly to rotate in the opposite direction to remove the tap.
[0012] As a preferred embodiment of the present invention, a thread surface finishing process is performed simultaneously during the tapping process: During the process of the tap exiting the hole, the elastic polishing sleeve installed at the rear of the tap is controlled to expand radially, so that the abrasive particles on the outer surface of the elastic polishing sleeve fit into the machined thread surface. As the tap rotates in the opposite direction to retract, the elastic polishing sleeve rotates with the tap and grinds and polishes the thread surface, removing microscopic burrs from the thread surface.
[0013] As a preferred embodiment of the present invention, the specific process steps of the chamfering process in step S7 include: Control the chamfering assembly to rotate at the seventh rotation speed and quickly approach the orifice; When the positioning guide head of the chamfering tool extends into the hole, the axial feed resistance of the chamfering tool is detected; When the axial feed resistance is detected to rise to the second current threshold, it is determined that the cutting edge of the chamfering tool has contacted the edge of the hole. The chamfering assembly is controlled to perform chamfering cutting at the eighth rotation speed and the fourth feed speed. During the chamfering cutting process, the chamfering depth is controlled by mechanically limiting the chamfering depth through the elastic limiting sleeve installed at the rear of the chamfering cutter. When the end face of the elastic limit sleeve contacts the surface of the blank, the chamfering assembly is controlled to stop feeding and maintain rotation for a preset time to perform friction polishing on the chamfered surface.
[0014] As a preferred embodiment of the present invention, the specific process steps for detection and sorting in step S8 include: The thread gauge inspection assembly is inserted into each hole one by one. The front end of the thread gauge inspection assembly is equipped with a standard thread section and a radial floating mechanism. When the standard thread section is screwed into the hole, the yaw amplitude of the radial floating mechanism is used to detect whether the thread is qualified and the hole position number of the thread that is not qualified is recorded. The chamfer of the orifice is scanned by a laser displacement sensor. The chamfer profile curve obtained by scanning is spatially superimposed and compared with the standard chamfer profile curve in the storage unit. The radial deviation value and axial deviation value of the chamfer profile are determined by comparing the interference fringe spacing formed by the grating projection between the chamfer profile curve and the standard chamfer profile curve. Based on the thread inspection results and chamfer profile deviation values, the blanks are classified and transported to the qualified product area, rework area, or scrap area.
[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses a visual inspection component to perform three-dimensional morphological scanning on the blank, and rigidly registers the actual spatial points with the standard hole distribution model. This can accurately identify the clamping position deviation of the blank and the dimensional tolerance of the workpiece itself, so that the hole coordinates of subsequent processing can be accurately matched with the actual blank position. This avoids the hole position deviation problem caused by blank clamping offset or workpiece deformation, and improves the positional accuracy of hole group processing.
[0016] 2. This invention uses a multi-axis machining head that simultaneously carries a drilling assembly, a tapping assembly, and a chamfering assembly. The automatic tool changer enables rapid switching between the three machining components, allowing drilling, tapping, and chamfering to be completed continuously at the same machining station without the need to transfer workpieces between different devices. This eliminates positioning errors caused by repeated clamping and ensures that the drilling center, tapping center, and chamfering center are highly coincident, resulting in a significant improvement in thread quality and chamfer concentricity.
[0017] 3. During the drilling process, this invention detects changes in the load current of the spindle drive motor, automatically identifies the moment when the drill tip contacts the surface of the blank, and automatically adjusts the feed rate according to the drilling depth. This allows it to adapt to the drilling characteristics of blanks made of different materials, avoids problems such as drill bit chipping or hole deviation caused by improper manual feed control, extends the service life of the drill bit, and improves the stability of drilling quality.
[0018] 4. This invention simultaneously performs in-hole chip removal during drilling. High-pressure pulsed airflow is intermittently injected into the drill bit through a pulsed airflow generator to blow the chips generated during drilling out of the hole in a timely manner. This avoids the problems of drill bit jamming and hole wall scratches caused by chip accumulation and blockage in the hole, and ensures the surface quality of the drilled hole. At the same time, the pulsed airflow and the drill bit speed are kept synchronized, realizing the coordinated control of chip removal and drilling process.
[0019] 5. In the tapping process, the present invention monitors the tapping axial force of each tap in real time through an axial force sensor. When the detected axial force exceeds the preset threshold, the feed movement of the tap is automatically paused. The feed is resumed after the axial force returns to normal. This can effectively avoid the problem of tap overload breakage caused by local hard spots or chip accumulation. At the same time, it can independently control the abnormal resistance encountered by individual taps in multi-axis synchronous tapping without affecting the normal tapping process of other taps, thus improving the reliability and yield of the tapping process.
[0020] 6. This invention performs thread surface finishing simultaneously during the tapping process. The elastic polishing sleeve at the rear of the tap grinds and polishes the thread surface when the tap is withdrawn. This allows thread forming and surface finishing to be completed in one pass, eliminating the need for a separate thread deburring process after tapping, thus shortening the processing flow. At the same time, the radial expansion of the polishing sleeve can be precisely controlled, achieving a uniform polishing effect for threads of different specifications, thereby effectively improving the thread surface quality.
[0021] 7. During the chamfering process, this invention detects the change in the axial feed resistance of the chamfering tool, automatically identifies the moment when the cutting edge contacts the edge of the hole, and precisely controls the chamfering depth through mechanical limiting of the elastic limiting sleeve. It can adapt to the chamfering requirements of blanks with different thicknesses and different hole diameters. The chamfering depth control is not affected by the flatness of the blank surface, ensuring the consistency of the chamfering dimensions. At the same time, after the chamfering is completed, it continues to rotate for friction polishing, so that the chamfered surface forms a uniform bright band, improving the product appearance quality.
[0022] 8. In the detection and sorting step, this invention uses a combination of a thread gauge detection component and a laser displacement sensor for dimensional detection. The thread gauge detection component judges the thread quality by the deflection amplitude of the radial floating mechanism, which can intuitively reflect the machining accuracy and fit performance of the thread. The laser displacement sensor determines the chamfer profile deviation by comparing moiré interference fringes. The detection accuracy is high and the detection results are intuitive and reliable. Based on the detection results, the blanks are automatically classified and transported to different areas, realizing integrated closed-loop control of processing and detection, and providing data support for subsequent process optimization. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the overall process of the integrated machining technology for drilling, tapping, and chamfering holes in electric railway accessories according to the present invention. Detailed Implementation
[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1
[0025] A process for integrated drilling, tapping, and chamfering of holes in power railway accessories includes the following steps: S1. The blank of the electric iron accessory to be processed is clamped and fixed in the processing station, and the blank is initially positioned. S2. Project coded structured light onto the blank surface through the vision detection component, acquire the structured light modulation image of the blank surface, and reconstruct the three-dimensional morphology data of the blank surface based on the structured light modulation image. S3. Retrieve the standard hole position distribution model from the storage unit, and perform spatial position fitting between the physical feature points in the three-dimensional topography data and the virtual feature points in the standard hole position distribution model to determine the actual processing coordinates of each hole position to be processed. S4. Drive the multi-axis machining head to the first machining position according to the actual machining coordinates; S5. Control the feed of the multi-axis drilling assembly mounted on the multi-axis machining head to simultaneously drill multiple holes in the blank. S6. After drilling is completed, drive the multi-axis machining head to switch to the tapping assembly and move to the second machining position to simultaneously tap multiple drilled holes. S7. After tapping is completed, drive the multi-axis machining head to switch to the chamfering assembly and move to the third machining position to simultaneously chamfer the edges of each hole. S8. The dimensions of the finished holes are inspected by the detection component, and the blanks are sorted and output according to the inspection results.
[0026] Furthermore, the specific process steps for projecting coded structured light in step S2 include: A low-density grating is used to perform a coarse scan of the overall outline of the blank, and to identify the edge outline and main feature areas of the blank. Based on the main feature regions identified by the coarse scan, the grating density and projection angle of the projection unit are adjusted to perform a high-density grating fine scan on the identified main feature regions. The overall contour data obtained by coarse scanning and the local feature data obtained by fine scanning are spatially fused to generate complete three-dimensional topographic data of the blank surface.
[0027] Furthermore, the specific process steps for spatial position fitting in step S3 include: Extract the actual spatial locations of at least three positioning reference holes or positioning reference surfaces from the complete three-dimensional topography data; The extracted actual spatial points are rigidly registered with the corresponding theoretical reference points in the standard hole distribution model to minimize the total spatial distance deviation between the actual spatial points and the theoretical reference points. After rigid registration is completed, the starting guide points of each hole to be processed are generated by mapping the theoretical coordinates of each hole in the standard hole distribution model into the three-dimensional shape data of the blank.
[0028] Furthermore, after generating the initial guide point, the process also includes a step of verifying each guide point individually. The multi-axis machining head is driven to move the point laser probe to each guide point. The point laser probe emits a laser beam perpendicularly to the surface of the blank and collects the actual surface reflection intensity value and the actual surface height value at each guide point. The actual surface reflection intensity value is compared with the standard reflection intensity threshold. When the reflection intensity value is lower than the standard reflection intensity threshold, it is determined that the guide point is located in the concave or edge area of the blank surface, and automatically shifts to a preset distance away from the concave or edge area to generate a corrected processing starting point.
[0029] Furthermore, the specific process steps of drilling in step S5 include: The control group drill assembly is idling and approaching the blank surface at a first rotation speed and a first feed speed. When the drill tip of the group drill assembly contacts the blank surface, the load current change of the spindle drive motor is detected. When the load current is detected to rise to the first current threshold, it is determined that the drill tip has cut into the surface of the blank, and then the group drill assembly is controlled to switch to the second rotation speed and the second feed speed for stable drilling. When the drilling depth reaches the preset hole depth, the control group drilling assembly automatically reduces the feed speed to the third feed speed until the preset hole depth is reached, thus completing the drilling process.
[0030] Furthermore, an in-hole chip removal process is performed simultaneously during the drilling process: While the drilling assembly is feeding, a high-pressure pulsed airflow is intermittently injected into the axial through hole inside the drill bit through a pulsed airflow generator connected to the tail of the drilling assembly. The high-pressure pulsed airflow is ejected from the chip removal hole at the drill tip, blowing the chips generated by drilling out of the hole in the opposite direction along the spiral groove outside the drill bit. The frequency of pulsed airflow is synchronized with the rotational speed of the drill bit, with one pulsed airflow injected for each revolution of the drill bit.
[0031] Furthermore, the specific process steps for tapping in step S6 include: Control the tapping assembly to rotate forward at the fourth rotation speed and feed rapidly to a preset distance above the hole opening; Switch to the fifth speed for slow feed, so that the tap guide enters the borehole; Once the tap is fully inserted into the hole, the tapping assembly is controlled to tap at the sixth rotation speed, while the axial force sensor installed at the tail of the tapping assembly monitors the tapping axial force in real time. When the axial force exceeds the preset force threshold, the tapping assembly is controlled to pause the feed and keep rotating until the axial force drops below the preset force threshold, then the feed is resumed to continue tapping. After tapping to the preset depth, control the tapping assembly to rotate in the opposite direction to remove the tap.
[0032] Furthermore, a thread surface finishing process is performed simultaneously during the tapping process: During the process of the tap exiting the hole, the elastic polishing sleeve installed at the rear of the tap is controlled to expand radially, so that the abrasive particles on the outer surface of the elastic polishing sleeve fit into the machined thread surface. As the tap rotates in the opposite direction to retract, the elastic polishing sleeve rotates with the tap and grinds and polishes the thread surface, removing microscopic burrs from the thread surface.
[0033] Furthermore, the specific process steps for chamfering in step S7 include: Control the chamfering assembly to rotate at the seventh rotation speed and quickly approach the orifice; When the positioning guide head of the chamfering tool extends into the hole, the axial feed resistance of the chamfering tool is detected; When the axial feed resistance is detected to rise to the second current threshold, it is determined that the cutting edge of the chamfering tool has contacted the edge of the hole. The chamfering assembly is controlled to perform chamfering cutting at the eighth rotation speed and the fourth feed speed. During the chamfering cutting process, the chamfering depth is controlled by mechanically limiting the chamfering depth through the elastic limiting sleeve installed at the rear of the chamfering cutter. When the end face of the elastic limit sleeve contacts the surface of the blank, the chamfering assembly is controlled to stop feeding and maintain rotation for a preset time to perform friction polishing on the chamfered surface.
[0034] Furthermore, the specific process steps for detection and sorting in step S8 include: The thread gauge inspection assembly is inserted into each hole one by one. The front end of the thread gauge inspection assembly is equipped with a standard thread section and a radial floating mechanism. When the standard thread section is screwed into the hole, the yaw amplitude of the radial floating mechanism is used to detect whether the thread is qualified and the hole position number of the thread that is not qualified is recorded. The chamfer of the orifice is scanned by a laser displacement sensor. The chamfer profile curve obtained by scanning is spatially superimposed and compared with the standard chamfer profile curve in the storage unit. The radial deviation value and axial deviation value of the chamfer profile are determined by comparing the interference fringe spacing formed by the grating projection between the chamfer profile curve and the standard chamfer profile curve. Based on the thread inspection results and chamfer profile deviation values, the blanks are classified and transported to the qualified product area, rework area, or scrap area. Example 2
[0035] This embodiment takes the batch processing of crossarm angle steel of a power transmission line tower as an example to describe in detail the integrated processing technology of drilling, tapping and chamfering of holes in power iron accessories. The crossarm angle steel is made of Q355B hot-rolled angle steel, with specifications of L125×10 and a length of 3200mm. There are 24 holes to be processed, including end connection holes and middle web holes. The hole diameter is required to be 14mm, the thread is M16, and the chamfer depth is 1.5mm.
[0036] In step S1, the crossarm angle steel blank is hoisted to the processing station. A hydraulic self-centering clamp is used to center and clamp the outer sides of the two flange plates of the angle steel. The clamping force of the clamp is preset to 8MPa. During the clamping process, the clamping pressure is monitored by the pressure sensor built into the clamp. When the clamping pressure is stable in the range of 7.8MPa to 8.2MPa, it is determined that the blank is clamped in place. After the clamping is completed, the multi-axis machining head is driven to move to the preset initial observation position above the blank. This position is about 300mm away from the surface of the blank to ensure that the vision inspection component has a complete field of view coverage.
[0037] In step S2, the vision inspection component includes three projection units arranged in a 120-degree ring and three corresponding imaging units. First, the projection units are activated to project a low-density grating with a line density of 2 lines / mm onto the blank surface. Simultaneously, the imaging units acquire a modulated image of the overall outline of the blank. By analyzing the stripe direction of the modulated image, the flange edge, end face, and preset process reference hole area of the blank are identified. Then, based on the main feature areas identified by the coarse scan, the grating density of the projection units is adjusted to 10 lines / mm, and the projection angle is adjusted to form a 15-degree angle with the normal of the blank surface. Fine scans are performed on the end connection hole area and the middle process reference hole area. After the fine scan is completed, the overall outline point cloud obtained by the coarse scan and the local high-density point cloud obtained by the fine scan are imported into the image processor. The image processor uses the coarse scan point cloud as a spatial skeleton and embeds the fine scan point cloud into the corresponding area position in the skeleton to generate complete three-dimensional topographic data of the blank surface. This data includes the overall outline information of the blank and the fine surface features of key areas.
[0038] In step S3, four positioning reference features on the blank are extracted from the complete three-dimensional topography data, namely the center points of the two end faces and the center points of the process reference holes on the two flanges. These four actual spatial points are rigidly registered with the four theoretical reference points in the pre-stored standard hole position distribution model in the storage unit. During the rigid registration process, the spatial orientation of the blank's three-dimensional topography data is iteratively adjusted to gradually reduce the spatial distance deviation between the four actual points and the theoretical points. When the sum of the squares of the four deviation values is less than 0.05 mm², the registration is completed. After the registration is completed, the blank's three-dimensional topography data and the standard hole position distribution model are spatially aligned. Then, based on the theoretical coordinates of the 24 holes in the standard hole position distribution model, the starting guide points of the 24 holes to be processed are mapped and generated in the blank's three-dimensional topography data.
[0039] In step S4, based on the 24 generated starting guide points, the control system plans the motion path of the multi-axis machining head. The multi-axis machining head first moves to the first hole group area, which contains 8 holes distributed in a rectangular shape. The multi-axis machining head stops 50mm above the center of this area, which is the first machining position.
[0040] In step S5, the multi-axis machining head carries a group drilling assembly containing eight high-speed steel drill bits with a diameter of 14mm. The arrangement of the drill bits is completely consistent with the distribution of the eight holes in the first hole group area. The group drilling assembly is controlled to idle and move downwards towards the surface of the blank at a speed of 800rpm and a feed rate of 50mm / min. When the eight drill tips simultaneously contact the surface of the blank, the load current of the spindle drive motor rises from the no-load 3.5A to 5.8A, reaching the preset first current threshold of 5.5A. The control system determines that the drill tip has cut into the surface of the blank and then controls the group drilling assembly to switch to a speed of 1200rpm and a feed rate of 120mm / min for stable drilling. During the drilling process, the spindle feed displacement is monitored in real time by a grating ruler. When the feed displacement reaches 90% of the preset hole depth of 14mm, i.e., 12.6mm, the control system automatically reduces the feed rate to 60mm / min until the feed displacement reaches 14.2mm and then stops feeding to complete the drilling. After the drilling is completed, the group drilling assembly returns to the safe position.
[0041] During the drilling process, a chip removal process is performed simultaneously in the hole. The pulse airflow generator is connected to the tail of the group drill assembly. Through the rotary joint, a high-pressure pulse airflow of 0.6MPa is intermittently injected into the axial through holes inside the eight drill bits. The trigger signal of the pulse airflow generator is synchronized with the spindle speed signal. For each revolution of the drill bit, the pulse airflow generator injects a high-pressure pulse airflow lasting 0.1 seconds into each drill bit. The high-pressure pulse airflow is ejected from two symmetrical chip removal holes at the drill tip, blowing the chips generated during drilling out of the hole along the spiral groove on the outside of the drill bit, thus preventing the chips from accumulating and clogging the hole.
[0042] In step S6, after drilling is completed, the multi-axis machining head moves to the tool change station. The group drill assembly is unloaded via an automatic tool changer, and a tapping assembly is installed. The tapping assembly contains eight M16 spiral flute taps made of powder metallurgy high-speed steel. The multi-axis machining head, carrying the tapping assembly, moves to a position 30mm above the first hole group area, i.e., the second machining position. The tapping assembly is controlled to rotate forward at 200 rpm and move rapidly downward at a feed rate of 100 mm / min. When the tap guide is 5mm from the hole opening, the speed is switched to 80 rpm and the feed rate to 15 mm / min for slow feeding, allowing the tap guide to smoothly enter the hole opening. After all eight taps are fully inserted into the hole... The system controls the tapping assembly to tap at a speed of 150 rpm. Simultaneously, eight axial force sensors installed at the tail of the tapping assembly monitor the axial force of each tap in real time. When the axial force of the third tap reaches 850 N, exceeding the preset 800 N force threshold, the control system immediately pauses the feed motion of the drive shaft where that tap is located, but maintains its rotation. The remaining seven taps continue to tap normally. After a pause of 0.5 seconds, the axial force of the third tap drops back to 650 N, and the control system resumes its feed motion to continue tapping. When all taps have tapped to the preset depth of 16 mm, the system controls the tapping assembly to rotate in the opposite direction at a speed of 300 rpm to remove the taps.
[0043] During the tapping process, a thread surface finishing process is performed simultaneously. As the tap exits the hole, the control system sends an unfolding command to the elastic polishing sleeve installed at the rear of each tap. The elastic polishing sleeve is made of polyurethane material, with 800-mesh cubic boron nitride abrasive particles evenly distributed on its outer surface. After receiving the command, the elastic polishing sleeve expands radially by 0.2mm, so that the abrasive particles closely adhere to the machined thread surface. As the tap rotates in the opposite direction at 300rpm to exit, the elastic polishing sleeve rotates synchronously with the tap and grinds and polishes the thread surface, effectively removing micro-burrs generated at the thread tips and sides, reducing the thread surface roughness from Ra3.2μm to Ra1.6μm.
[0044] In step S7, after tapping is completed, the multi-axis machining head moves back to the tool change station. The tapping assembly is removed via the automatic tool changer, and a chamfering assembly is installed. The chamfering assembly contains eight 90-degree chamfering cutters. Each chamfering cutter has a 13.8mm diameter positioning guide head at its front end, used to extend into the hole to ensure concentricity of the chamfer. The multi-axis machining head, carrying the chamfering assembly, moves to a position 25mm above the first hole group area, i.e., the third machining position. The chamfering assembly is controlled to rotate at 600rpm and rapidly approach the hole opening at a feed rate of 80mm / min. When the positioning guide head of the chamfering cutter extends approximately 3mm into the hole, the axial feed resistance of the chamfering cutter is detected to rise to 18N, corresponding to a rise in the spindle drive motor load current to 4.2N. When the preset second current threshold of 4.0A is reached, it is determined that the cutting edge of the chamfering cutter has contacted the edge of the hole. Then, the chamfering assembly is controlled to switch to a rotation speed of 400 rpm and a feed speed of 30 mm / min for chamfering cutting. During the chamfering cutting process, the elastic limiting sleeve installed at the rear of each chamfering cutter gradually approaches the surface of the blank as the chamfering cutter feeds. When the end face of the elastic limiting sleeve contacts the surface of the blank, the compression spring inside is compressed by 2 mm, triggering the mechanical limit switch. The control system immediately stops the feed movement of the chamfering cutter. After the feed stops, the chamfering assembly remains in a rotating state for 2 seconds. The polishing belt at the rear of the chamfering cutter is used to rub and polish the chamfered surface, so that the surface finish of the chamfered surface reaches Ra1.2μm.
[0045] In step S8, after the chamfering is completed, the multi-axis machining head moves to the inspection station and performs dimensional inspection on 24 holes using an inspection assembly. The inspection assembly includes 8 thread gauge inspection assemblies and 8 laser displacement sensors. First, the 8 thread gauge inspection assemblies are driven to simultaneously extend into the 8 holes in the first hole group area. Each thread gauge inspection assembly has a standard M16 thread segment with a length of 20mm at its front end. The rear of the thread segment is connected to a radial floating mechanism, which allows the thread segment to float ±0.3mm in the radial direction. When the standard thread segment is screwed into the hole, the displacement sensor built into the radial floating mechanism detects the runout of the thread segment. If the runout is less than 0.1mm, the thread is considered qualified; if the runout is between 0.1mm and 0.3mm, the thread is considered to have a slight defect; and if the runout exceeds 0.3mm, the thread is considered unqualified. After the inspection is completed, the thread inspection results for each hole are recorded. In the first hole group area, 2 holes were found to have a thread runout of 0.15mm, which were marked as slightly defective holes.
[0046] Subsequently, eight laser displacement sensors were used to scan the contours of the eight chamfered openings in the first group of holes. The laser displacement sensors employed the point laser triangulation method, achieving a measurement accuracy of ±0.01mm. The sensors scanned the chamfered surface along a spiral path, collecting approximately 200 contour points for each chamfer. The obtained chamfer contour point cloud was imported into an image processor and spatially superimposed and compared with a standard 90-degree chamfer contour template in the storage unit. A fine grating with a spacing of 0.02mm was projected between the chamfer contour point cloud and the standard contour template. The projection of the grating between the two was observed. The variation in the spacing of the formed moiré interference fringes was used to determine the radial and axial deviations of the chamfer profile. When the interference fringe spacing was uniform and less than 0.5 mm, the chamfer profile was deemed acceptable. When the interference fringe spacing was between 0.5 mm and 1.0 mm, the chamfer was deemed to have a slight deviation. When the interference fringe spacing was greater than 1.0 mm or a break was observed, the chamfer was deemed unacceptable. The test results showed that among the eight chamfers in the first hole group area, seven had interference fringe spacing between 0.3 mm and 0.4 mm, which were deemed acceptable; one interference fringe spacing was 0.7 mm, which was deemed to have a slight deviation.
[0047] Based on the combined results of thread inspection and chamfer profile inspection, blanks with all qualified threads and chamfers out of 24 holes are transported to the qualified product area; blanks with minor defects but no more than 3 defects are transported to the rework area; blanks with unqualified holes or more than 3 defects are transported to the scrap area. In this embodiment, the crossbeam angle steel processed was inspected, and 2 out of 24 holes were all qualified, while 2 holes had minor defects. The blanks were transported to the rework area for subsequent repair processing. Example 3
[0048] This embodiment takes the processing of the connecting plate of a substation frame column as an example to verify the adaptability of the processing technology of the present invention to different materials and structural features. The connecting plate is made of Q420B high-strength steel plate with a thickness of 16mm and a plane size of 450mm×320mm. There are a total of 16 holes to be processed, including 8 bolt holes with a diameter of 18mm and 8 M20 threaded holes. All holes are required to be chamfered at 2mm×45°.
[0049] In step S1, the connecting plate blank is placed flat on the vacuum adsorption platform of the processing station. The surface of the vacuum adsorption platform is provided with crisscrossing sealing grooves, and rubber sealing strips are embedded in the grooves. The vacuum pump is started to create a negative pressure environment of -0.06MPa between the adsorption platform and the bottom surface of the blank, so that the blank is firmly adsorbed and fixed. During the adsorption process, the adsorption pressure is monitored in real time through four pressure monitoring points built into the platform. When the pressure values of the four monitoring points are all within the range of -0.058MPa to -0.062MPa, it is determined that the blank is clamped in place. After clamping is completed, the multi-axis machining head is driven to move to 250mm above the center of the blank, ready for visual inspection.
[0050] In step S2, after the vision inspection component is started, it first projects an orthogonal grating with a line density of 3 lines / mm onto the surface of the blank to perform a coarse scan of the overall outline of the blank. By analyzing the coarse scan image, the four corner areas of the blank and the two pre-processed process positioning hole areas are identified. Then, the grating density of the projection unit is adjusted to 12 lines / mm, and the projection angle is adjusted to form a 20-degree angle with the normal of the blank surface. The process positioning hole area and the hole group area to be processed are then finely scanned. During the fine scan, the projection unit projects a horizontal grating and a vertical grating in sequence, and the imaging unit acquires the grating modulation images in the two directions respectively. The overall outline point cloud obtained by the coarse scan is spatially registered and fused with the high-density point cloud obtained by the fine scan to generate complete three-dimensional topography data containing the overall outline of the blank and local fine features. In this data, the edge outline of the process positioning hole is clearly distinguishable, and the positioning accuracy of the hole center position reaches ±0.03mm.
[0051] In step S3, two process positioning holes and two corner points on the blank are extracted from the complete three-dimensional topography data as positioning reference features. These four actual spatial points are rigidly registered with the four theoretical reference points in the standard hole position distribution model. The rigid registration is carried out by three-point coarse adjustment and four-point fine adjustment. First, the two process positioning holes and one corner point are initially registered to make the average spatial deviation of the three points less than 0.1mm. Then, the fourth corner point is added for overall fine adjustment. Through multiple iterations, the maximum spatial deviation of the four points is made less than 0.06mm. After the registration is completed, the three-dimensional topography data of the blank is accurately aligned with the standard hole position distribution model. Then, based on the theoretical coordinates of the 16 holes in the standard hole position distribution model, the starting guide points of the 16 holes to be processed are mapped and generated in the three-dimensional topography data of the blank.
[0052] In step S4, based on the distribution of the 16 starting guide points, the control system divides the 16 hole positions into two hole group areas, each containing 8 hole positions. The multi-axis machining head first moves to 40mm above the center of the first hole group area, i.e., the first machining position, in preparation for drilling.
[0053] In step S5, the multi-axis machining head carries a group drill assembly containing eight drill bits. Four of these are 18mm diameter twist drills used for machining bolt through holes, and four are 17.5mm diameter twist drills used for machining threaded hole bottom holes. The drill bit arrangement is completely consistent with the distribution of the eight holes in the first hole group area. The group drill assembly is controlled to rotate at 600 rpm and feed at 40mm / min, moving downwards towards the blank surface. When the drill tip contacts the blank surface, the load current of the spindle drive motor rises from the no-load 4.2A to 6.5A, reaching the preset first current threshold of 6.0A. The control system determines that the drill tip has cut into the blank surface and then controls the group drill assembly to switch to a rotation speed of 1000 rpm and a feed rate of 100mm / min for stable drilling. When the drilling depth reaches 85% of the preset hole depth of 16mm, i.e., 13.6mm, the control system automatically reduces the feed rate to 50mm / min until the feed displacement reaches 16.2mm, at which point the feed stops, completing the drilling process.
[0054] During the drilling process, a chip removal process is performed simultaneously inside the hole. A pulse airflow generator intermittently injects high-pressure pulse airflow into the axial through holes inside the eight drill bits at a pressure of 0.5 MPa. The frequency of the pulse airflow is set to 1.2 times the drill bit speed, that is, a pulse airflow is injected once every 0.83 rotations. The frequency slightly higher than the speed ensures that the chips inside the hole are removed in time. The high-pressure pulse airflow is ejected from the chip removal hole at the drill tip, blowing the short chips generated during drilling out of the hole along the drill bit's spiral groove, avoiding the accumulation of chips at the bottom of the hole and affecting the drilling accuracy.
[0055] In step S6, after drilling is completed, the multi-axis machining head moves to the tool change station. The group drill assembly is removed via an automatic tool changer, and a tapping assembly is installed. The tapping assembly contains four M20 spiral flute taps for machining four threaded holes. The multi-axis machining head, carrying the tapping assembly, moves to a position 30mm above the first hole group area, i.e., the second machining position. The tapping assembly is controlled to rotate forward at 150 rpm and move rapidly downward at a feed rate of 80 mm / min. When the tap guide is 3mm from the hole opening, the speed is switched to 60 rpm and the feed rate to 12 mm / min for slow feed, allowing the tap guide to smoothly enter the bottom hole. Once the tap is fully inside the hole, the tapping assembly is controlled to rotate... The tapping speed is 120 rpm. At the same time, the axial force is monitored in real time by an axial force sensor installed at the tail of the tapping assembly. During the tapping process, due to the high strength of Q420B steel, the tapping axial force fluctuates greatly. When any axial force exceeds the preset 900N force threshold, the control system immediately stops the feed motion of the drive shaft where the tap is located, keeps it rotating and waits for the axial force to drop. The pause time is dynamically adjusted according to the axial force deviation. The larger the deviation, the longer the pause time, with a maximum of 1.2 seconds. When the axial force drops below 900N, the feed is resumed and tapping continues. After tapping to the preset depth of 20mm, the tapping assembly is controlled to rotate in the opposite direction to remove the tap.
[0056] During the tapping process, a thread surface finishing process is performed simultaneously. As the tap exits the hole, the elastic polishing sleeve installed at the rear of the tap receives the command and expands radially, so that the 1000-mesh silicon carbide abrasive particles evenly distributed on the outer surface adhere to the thread surface. As the tap rotates in the opposite direction at 250 rpm to exit, the elastic polishing sleeve rotates with the tap and grinds and polishes the thread surface, effectively removing the micro-cracks and burrs on the thread surface that are easily generated during the tapping of high-strength steel, and improving the thread surface quality.
[0057] In step S7, after tapping is completed, the multi-axis machining head moves to the tool change station. The tapping assembly is removed via an automatic tool changer, and a chamfering assembly is installed. The chamfering assembly contains eight 45-degree chamfering cutters for chamfering eight holes, four of which are bolt holes and four are threaded holes. The multi-axis machining head, carrying the chamfering assembly, moves to a position 20mm above the first hole group area, i.e., the third machining position. The chamfering assembly is controlled to rotate at 800 rpm and rapidly approach the hole opening at a feed rate of 60mm / min. When the chamfering cutter's positioning guide head extends approximately 2.5mm into the hole, the axial feed resistance of the chamfering cutter is detected to rise to 22N, corresponding to a rise in the spindle drive motor load current to 4.8A, reaching the preset second current threshold of 4.5A. A. Once it is determined that the cutting edge of the chamfering cutter has contacted the edge of the hole, the chamfering assembly is then switched to a rotation speed of 500 rpm and a feed speed of 25 mm / min for chamfering. During the chamfering process, the elastic limiting sleeve installed at the rear of the chamfering cutter gradually approaches the surface of the blank as it feeds. Due to the large thickness of the connecting plate in this embodiment, the limiting stroke of the elastic limiting sleeve is preset to 2.2 mm to ensure that the chamfering depth is accurately controlled within the range of 2.0 mm ± 0.1 mm. When the end face of the elastic limiting sleeve contacts the surface of the blank, the mechanical limit switch is triggered, and the control system immediately stops the feed movement of the chamfering cutter. After the feed stops, the chamfering assembly remains in a rotating state for 3 seconds to perform friction polishing on the chamfered surface, so that a uniform bright band is formed on the chamfered surface.
[0058] In step S8, after the chamfering is completed, the multi-axis machining head moves to the inspection station and performs dimensional inspection on 16 holes using an inspection assembly. The inspection assembly includes 4 thread gauge inspection assemblies and 8 laser displacement sensors. First, the 4 thread gauge inspection assemblies are driven to simultaneously extend into the 4 threaded holes for inspection. The front end of the thread gauge inspection assembly is equipped with a standard M20 thread segment with a length of 25mm. The rear end of the thread segment is connected to a radial floating mechanism. When the standard thread segment is screwed into the hole, the thread quality is detected by the deflection amplitude of the radial floating mechanism. If the deflection amplitude is less than 0.12mm, the thread is considered qualified; if the deflection amplitude is between 0.12mm and 0.35mm, the thread is considered to have a slight defect; and if the deflection amplitude exceeds 0.35mm, the thread is considered unqualified. The inspection results show that 3 of the 4 threaded holes have a deflection amplitude between 0.08mm and 0.10mm, which is considered qualified; and 1 has a deflection amplitude of 0.28mm, which is considered to have a slight defect.
[0059] Subsequently, eight laser displacement sensors were used to scan the contours of the eight chamfered openings. The laser displacement sensors scanned the chamfered surface along a circular path, collecting approximately 150 contour points for each chamfer. The obtained chamfer contour point cloud was then spatially superimposed and compared with a standard 45-degree chamfer contour template in the storage unit. During the comparison, a fine grating with a spacing of 0.03 mm was projected between the chamfer contour point cloud and the standard contour template. By observing the shape and spacing of the moiré interference fringes formed by the grating projection, the deviation of the chamfer contour was determined. When the interference fringes were straight and the spacing was uniform, the chamfer contour was deemed acceptable; when the interference fringes were bent or the spacing was uneven, the chamfer was deemed to have a deviation; when the interference fringes were broken or blurred, the chamfer was deemed unacceptable. The test results showed that among the eight chamfers, seven had straight and uniform interference fringes, which were deemed acceptable; the interference fringes of one chamfer showed slight bending, which was deemed to have a slight deviation.
[0060] Based on the combined results of thread inspection and chamfer profile inspection, blanks with all 16 holes passing inspection are transported to the qualified product area; blanks with minor defects but no more than 2 defective holes are transported to the rework area; and blanks with unqualified holes or more than 2 defective holes are transported to the scrap area. In this embodiment, the connecting plate processed was inspected, and 14 out of 16 holes were all qualified, while 2 holes had minor defects. The blanks were transported to the rework area. During rework, one threaded hole and one chamfer with minor defects were partially repaired. After repair, the plate passed the re-inspection and can finally be used as a qualified product.
[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.
Claims
1. A process for integrated drilling, tapping, and chamfering of holes in power railway accessories, characterized in that, Includes the following steps: S1. The blank of the electric iron accessory to be processed is clamped and fixed in the processing station, and the blank is initially positioned. S2. Project coded structured light onto the surface of the blank through the vision detection component, acquire the structured light modulation image of the blank surface, and reconstruct the three-dimensional morphology data of the blank surface based on the structured light modulation image. S3. Retrieve the standard hole position distribution model from the storage unit, and perform spatial position fitting between the physical feature points in the three-dimensional topography data and the virtual feature points in the standard hole position distribution model to determine the actual processing coordinates of each hole position to be processed. S4. Drive the multi-axis machining head to the first machining position according to the actual machining coordinates; S5. Control the feed of the multi-axis drilling assembly mounted on the multi-axis machining head to simultaneously drill multiple holes in the blank. S6. After drilling is completed, drive the multi-axis machining head to switch to the tapping assembly and move to the second machining position to simultaneously tap multiple drilled holes. S7. After tapping is completed, drive the multi-axis machining head to switch to the chamfering assembly and move to the third machining position to simultaneously chamfer the edges of each hole. S8. The dimensions of the finished holes are inspected by the detection component, and the blanks are sorted and output according to the inspection results.
2. The processing technology according to claim 1, characterized in that, The specific process steps for projecting encoded structured light in step S2 include: A low-density grating is used to perform a coarse scan of the overall outline of the blank, and to identify the edge outline and main feature areas of the blank. Based on the main feature regions identified by the coarse scan, the grating density and projection angle of the projection unit are adjusted to perform a high-density grating fine scan on the identified main feature regions. The overall contour data obtained by coarse scanning and the local feature data obtained by fine scanning are spatially fused to generate complete three-dimensional topographic data of the blank surface.
3. The processing technology according to claim 2, characterized in that, The specific process steps for spatial position fitting in step S3 include: Extract the actual spatial locations of at least three positioning reference holes or positioning reference surfaces from the complete three-dimensional topography data; The extracted actual spatial points are rigidly registered with the corresponding theoretical reference points in the standard hole distribution model to minimize the total spatial distance deviation between the actual spatial points and the theoretical reference points. After rigid registration is completed, the starting guide points of each hole to be processed are generated by mapping the theoretical coordinates of each hole in the standard hole distribution model into the three-dimensional shape data of the blank.
4. The processing technology according to claim 3, characterized in that, After generating the initial guide point, the process also includes a step of verifying the guide point point by point: The multi-axis machining head is driven to move the point laser probe to each guide point. The point laser probe emits a laser beam perpendicularly to the surface of the blank and collects the actual surface reflection intensity value and the actual surface height value at each guide point. The actual surface reflection intensity value is compared with the standard reflection intensity threshold. When the reflection intensity value is lower than the standard reflection intensity threshold, it is determined that the guide point is located in the concave or edge area of the blank surface, and automatically shifts to a preset distance away from the concave or edge area to generate a corrected processing starting point.
5. The processing technology according to claim 1, characterized in that, The specific process steps of drilling in step S5 include: The control group drill assembly is idling and approaching the blank surface at a first rotation speed and a first feed speed. When the drill tip of the group drill assembly contacts the blank surface, the load current change of the spindle drive motor is detected. When the load current is detected to rise to the first current threshold, it is determined that the drill tip has cut into the surface of the blank, and then the group drill assembly is controlled to switch to the second rotation speed and the second feed speed for stable drilling. When the drilling depth reaches the preset hole depth, the control group drilling assembly automatically reduces the feed speed to the third feed speed until the preset hole depth is reached, thus completing the drilling process.
6. The processing technology according to claim 5, characterized in that, The in-hole chip removal process is performed simultaneously during the drilling process: While the drilling assembly is feeding, a high-pressure pulsed airflow is intermittently injected into the axial through hole inside the drill bit through a pulsed airflow generator connected to the tail of the drilling assembly. The high-pressure pulsed airflow is ejected from the chip removal hole at the drill tip, blowing the chips generated by drilling out of the hole in the opposite direction along the spiral groove outside the drill bit. The frequency of pulsed airflow is synchronized with the rotational speed of the drill bit, with one pulsed airflow injected for each revolution of the drill bit.
7. The processing technology according to claim 1, characterized in that, The specific process steps for tapping in step S6 include: Control the tapping assembly to rotate forward at the fourth rotation speed and feed rapidly to a preset distance above the hole opening; Switch to the fifth speed for slow feed, so that the tap guide enters the borehole; Once the tap is fully inserted into the hole, the tapping assembly is controlled to tap at the sixth rotation speed, while the axial force sensor installed at the tail of the tapping assembly monitors the tapping axial force in real time. When the axial force exceeds the preset force threshold, the tapping assembly is controlled to pause the feed and keep rotating until the axial force drops below the preset force threshold, then the feed is resumed to continue tapping. After tapping to the preset depth, control the tapping assembly to rotate in the opposite direction to remove the tap.
8. The processing technology according to claim 7, characterized in that, The thread surface finishing process is performed simultaneously during the tapping process. During the process of the tap exiting the hole, the elastic polishing sleeve installed at the rear of the tap is controlled to expand radially, so that the abrasive particles on the outer surface of the elastic polishing sleeve fit into the machined thread surface. As the tap rotates in the opposite direction to retract, the elastic polishing sleeve rotates with the tap and grinds and polishes the thread surface, removing microscopic burrs from the thread surface.
9. The processing technology according to claim 1, characterized in that, The specific process steps for chamfering in step S7 include: Control the chamfering assembly to rotate at the seventh rotation speed and quickly approach the orifice; When the positioning guide head of the chamfering tool extends into the hole, the axial feed resistance of the chamfering tool is detected; When the axial feed resistance is detected to rise to the second current threshold, it is determined that the cutting edge of the chamfering tool has contacted the edge of the hole. The chamfering assembly is controlled to perform chamfering cutting at the eighth rotation speed and the fourth feed speed. During the chamfering cutting process, the chamfering depth is controlled by mechanically limiting the chamfering depth through the elastic limiting sleeve installed at the rear of the chamfering cutter. When the end face of the elastic limit sleeve contacts the surface of the blank, the chamfering assembly is controlled to stop feeding and maintain rotation for a preset time to perform friction polishing on the chamfered surface.
10. The processing technology according to claim 1, characterized in that, The specific process steps for detection and sorting in step S8 include: The thread gauge inspection assembly is inserted into each hole one by one. The front end of the thread gauge inspection assembly is equipped with a standard thread section and a radial floating mechanism. When the standard thread section is screwed into the hole, the yaw amplitude of the radial floating mechanism is used to detect whether the thread is qualified and the hole position number of the thread that is not qualified is recorded. The chamfer of the orifice is scanned by a laser displacement sensor. The chamfer profile curve obtained by scanning is spatially superimposed and compared with the standard chamfer profile curve in the storage unit. The radial deviation value and axial deviation value of the chamfer profile are determined by comparing the interference fringe spacing formed by the grating projection between the chamfer profile curve and the standard chamfer profile curve. Based on the thread inspection results and chamfer profile deviation values, the blanks are classified and transported to the qualified product area, rework area, or scrap area.