Parallel machining method of turning-milling combined machine tool and double-station turning-milling combined machine tool

Abstract

The present application relates to turning and milling combined machining technical field, especially to a kind of parallel processing method of turning and milling combined machine tool and double-station turning and milling combined machine tool.Parallel processing method includes: turning machining, two power heads are installed cutter, at this time workbench rotates, two cutters are set different cutting depth and simultaneously turn workpiece machining;Milling machining, two power heads are installed milling cutter, at this time workbench is stationary, two milling cutters simultaneously mill the structure on different positions of workpiece.Processing efficiency is low, milling precision is poor, energy consumption is high and the problem that processing scene is limited is solved by the present application, and the parallel processing effect of high efficiency, high precision, low energy consumption and wide applicability is realized.

Description

Technical Field

[0001] This invention relates to the field of mill-turn machining technology, and more particularly to a parallel machining method for a mill-turn machine tool and a dual-station mill-turn machine tool. Background Technology

[0002] A milling-turning machine tool is a common metal cutting equipment, mainly used for turning and milling rotary parts. In fields such as wind power and construction machinery, large gear rings, slewing bearings, and other parts typically require turning the outer diameter and end face first, followed by milling the slots or grooves. Traditional milling-turning machines generally add a milling power head to a vertical lathe, forming two fixed spindles for turning and milling. During machining, when turning, the turning power head feeds, and the worktable rotates the workpiece; when milling, the worktable still needs to rotate at a set angle, serving as a feed axis for milling, coordinating with the rotation of the milling cutter and the movement of the power head to machine slots or holes.

[0003] In the above processing methods, only one power head is engaged in each processing step, while the other remains idle, resulting in low equipment utilization and limited processing efficiency. During milling, the worktable needs to rotate to cooperate with the milling cutter for feed. For large rotary worktables with diameters of several meters or even more than ten meters, the rotational accuracy is difficult to achieve the level of a precision spindle, affecting processing accuracy. Simultaneously, driving the high-precision rotation of the large-mass worktable consumes a significant amount of energy. Moreover, when the workpiece has multiple slots arranged in a circular or mirror pattern, it is difficult to achieve simultaneous and efficient processing by two milling heads because only the single-axis rotation of the worktable can be used to process them one by one. Furthermore, for structures with different shapes, it is impossible to simultaneously meet the processing needs of two milling heads through the rotation of the same worktable. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a parallel machining method for a mill-turning composite machine tool and a dual-station mill-turning composite machine tool that can improve machining efficiency, machining accuracy, and expand machining range.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: In a first aspect, embodiments of the present invention provide a parallel machining method for a milling-turning composite machine tool, the milling-turning composite machine tool including a horizontal worktable and two vertical power heads, the parallel machining method including: during turning, both power heads are equipped with turning tools, the worktable rotates, and the two turning tools are set with different cutting depths to simultaneously turn the workpiece; during milling, both power heads are equipped with milling cutters, the worktable is stationary, and the two milling cutters simultaneously mill structures at different positions on the workpiece.

[0006] As a further technical solution, when multiple positions need to be milled, the structure at two positions is milled simultaneously while the worktable is stationary. After the structure at the two positions is machined, the worktable rotates and / or the power head moves to the next working position, and the two power heads continue to mill simultaneously.

[0007] As a further technical solution, when a set of circumferential array features needs to be processed, the processing positions of the two power heads are always 180 degrees apart, with one power head milling in a clockwise direction and the other power head milling in a counterclockwise direction.

[0008] As a further technical solution, when the quantity, type, or location of the structures to be processed is unevenly distributed, a task allocation step is also included: The workpiece machining program is decomposed into multiple machining elements, each corresponding to a continuous cutting process; Extract the processing location, processing type, and estimated processing time for each processing element; Arrange all processing elements in descending order of estimated processing time, and assign each processing element to the power head with the shorter current cumulative estimated processing time. If the cumulative estimated processing time of the first power head is less than or equal to the cumulative estimated processing time of the second power head, assign the processing element to the first power head; otherwise, assign it to the second power head. Check whether the processing element in the task list of each power head after assignment is within the reach range of that power head. If it is outside the reach range, force the processing element to be assigned to another power head.

[0009] As a further technical solution, the estimated machining time is calculated based on the cutting depth, feed rate, spindle speed, and machining path length corresponding to the machining element.

[0010] As a further technical solution, dynamic adjustment steps are also included: The actual processing time of each processing element is recorded in real time during the processing process; Once one power head has completed all the processing elements in its task list, it checks whether there are any unfinished processing elements in the task list of another power head. If so, and the unfinished processing element is within the reach of the power head that has completed the task, the unfinished processing element is transferred to the power head that has completed the task for execution.

[0011] As a further technical solution, when transferring unfinished processing elements to power heads that have completed their tasks, the remaining processing time of the two power heads after the transfer is made to be approximately equal.

[0012] Secondly, embodiments of the present invention also provide a dual-station milling and turning composite machine tool for the parallel machining method of the milling and turning composite machine tool as described above, including a turntable base, a worktable, two columns, a crossbeam, a transmission mechanism, and two milling and turning power heads; Two columns are fixed to the turntable base, and a crossbeam is fixed to the upper end of the two columns. The worktable is installed on the turntable base and can rotate around the vertical axis. Each milling head is mounted on a crossbeam and can move laterally along the crossbeam. The milling head includes a vertical ram, a horizontal ram, a headstock, and a milling spindle. The vertical ram is mounted on the crossbeam and can move vertically. The horizontal ram is mounted at the lower end of the vertical ram and can move horizontally back and forth. The headstock is fixed at the front end of the horizontal ram, and the milling spindle is installed inside the headstock. The transmission mechanism includes a Y-axis transmission mechanism, a Z-axis transmission mechanism, and an X-axis transmission mechanism. The Y-axis transmission mechanism is used to drive the milling head to move laterally along the crossbeam, the Z-axis transmission mechanism is used to drive the vertical slide to move vertically, and the X-axis transmission mechanism is used to drive the horizontal slide to move horizontally forward and backward.

[0013] As a further technical solution, each milling head also includes a transverse slide, a slide plate, a horizontal slide, and a slide plate; The transverse slide is set on the crossbeam, and the slide pressure plate and the transverse slide form a guide space. The vertical slide is installed in the guide space and can slide in the vertical direction. The horizontal slide block is fixed to the lower end face of the vertical slide block. The slide block pressure plate and the horizontal slide block together form a guide space. The horizontal slide block is installed in this guide space and can slide in the horizontal back-and-forth direction.

[0014] As a further technical solution, it also includes a first cylindrical pin and a second cylindrical pin. The first cylindrical pin is disposed between the vertical slide block and the horizontal slide block for positioning connection, and the second cylindrical pin is disposed between the horizontal slide block and the spindle box for positioning connection.

[0015] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: In the turning process, this invention uses two power heads simultaneously equipped with cutting tools and performing turning at different depths of cut, nearly doubling the cutting efficiency compared to traditional single-tool machining. In the milling process, two power heads simultaneously equipped with milling cutters while the worktable remains stationary, avoiding the problems of low rotational accuracy and high energy consumption associated with large rotary worktables. Furthermore, because the worktable is stationary, the two milling cutters can move via their independent linear axes, enabling the simultaneous machining of circular arrays, mirror arrays, or structures with completely different shapes. This overcomes the limitations of traditional methods that rely on worktable rotation in conjunction with a single milling cutter, greatly expanding the machining scenarios. Therefore, this invention solves the problems of low machining efficiency, poor milling accuracy, high energy consumption, and limited machining scenarios, achieving high-efficiency, high-precision, low-energy-consumption, and widely applicable parallel machining effects.

[0016] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0018] Figure 1 This is a schematic diagram of the processing method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the overall machine tool provided in an embodiment of the present invention; Figure 3 This is a cross-sectional view of the milling head provided in an embodiment of the present invention; In the diagram: 1. Turntable base; 2. Worktable; 3. Workpiece; 4. Milling / turning power head; 5. Y-axis transmission mechanism; 6. Crossbeam; 7. Column; 8. Vertical slide; 9. Z-axis transmission mechanism; 10. Transverse slide; 11. Slide plate; 12. First cylindrical pin; 13. Horizontal slide; 14. Milling / turning electric spindle; 15. Spindle box; 16. Second cylindrical pin; 17. Slide plate; 18. Horizontal slide; 19. X-axis transmission mechanism; Detailed Implementation To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0019] Generally speaking, the terms "comprising" and "including" only indicate that the steps and elements are explicitly identified, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

[0020] Example 1 In one typical embodiment of this disclosure, a parallel machining method for a milling-turning machine tool is provided.

[0021] The milling-turning machine tool includes a horizontal worktable 2 and two vertical power heads. In the specific example disclosed, the milling-turning machine tool uses a horizontally arranged worktable 2, which can rotate around a vertical axis. Two vertical power heads are arranged above the worktable 2, each of which is a spindle unit capable of mounting a turning tool or a milling cutter. This transforms the traditional fixed-function mode of the two power heads in milling-turning machine tools into a flexible mode where both power heads can perform turning or milling. This machine tool structure is mainly used for the efficient machining of large rotating parts in fields such as wind power and engineering machinery. For example, parts such as gear rings and slewing bearings require first turning the outer diameter and end face, and then milling slots or grooves.

[0022] The parallel processing method is as follows: Figure 1 As shown, it includes: During S100 turning, both power heads are equipped with cutting tools. At this time, the worktable 2 rotates, and the two cutting tools are set with different cutting depths to simultaneously turn the workpiece 3. During S200 milling, both power heads are equipped with milling cutters. At this time, the worktable 2 is stationary, and the two milling cutters simultaneously mill the structure at different positions on the workpiece 3.

[0023] Specifically, during turning, the operator or an automatic tool changer mounts cutting tools on both power heads. The worktable 2 then rotates, causing the workpiece 3 to rotate. Both cutting tools simultaneously contact the surface of the workpiece 3, but are set with different depths of cut. By allocating different depths of cut, machining efficiency is improved.

[0024] During milling, both power heads are replaced with milling cutters. The worktable 2 remains stationary during milling, no longer rotating. The two milling cutters independently perform milling operations at different positions on the workpiece 3. Each power head can achieve three-axis linkage, thus enabling the machining of various structures such as slots, holes, and planes. Traditional milling requires the worktable 2 to rotate as one of the feed axes, but in this method, the worktable 2 is only used for positioning and indexing, and it is locked during the milling process.

[0025] In turning and milling operations, the two power heads work simultaneously, shortening machining time and improving machining efficiency. During turning, the different cutting depths of the two cutting tools, combined with the rotation of the worktable 2, result in a more rational distribution of the total cutting force, avoiding heat accumulation and concentrated tool wear seen with single-tool cutting. Furthermore, during milling, the worktable 2 remains stationary, eliminating reliance on the high-precision rotation of the large rotary worktable 2. Instead, it relies on the high-precision positioning and movement of the linear axis and electric spindle, improving machining accuracy. Simultaneously, the energy consumed to drive the smaller power head is significantly reduced compared to driving the larger worktable 2. In addition, because the worktable 2 is stationary and the two power heads operate independently in three-axis linkage, each milling cutter can move according to its own machining trajectory. Therefore, it is possible to simultaneously machine two symmetrically positioned slots in a circular array, simultaneously machine mirror-distributed structures, and even simultaneously machine two structures with completely different shapes, such as one power head milling a square slot while the other machines a round hole.

[0026] In other specific examples of this disclosure, when multiple positions need to be milled, the worktable 2 is stationary while the structure at two positions is milled simultaneously. After the structure at the two positions is machined, the worktable 2 rotates and / or the power head moves to the next working position, and the two power heads continue to mill simultaneously.

[0027] In practice, the various positions on workpiece 3 that need to be milled are considered as multiple machining stations. First, the worktable 2 rotates to the first machining angle and locks. At this time, the two power heads are aligned with the two positions to be machined and mill simultaneously. After the machining of these two positions is completed, the system controls the worktable 2 to rotate to the next machining angle, or controls the power heads to move laterally or longitudinally to a new machining position, and then the two power heads mill simultaneously again. This process is repeated until all positions are machined.

[0028] It should be noted that the rotation of the worktable 2 and the movement of the power head can be used individually or in combination. For example, for multiple grooves evenly distributed around the circumference, usually only the worktable 2 needs to rotate by the same angle, and the power head does not need to move laterally. However, for structures distributed at different radii or different axial heights on the workpiece 3, the power head needs to move laterally for alignment.

[0029] By rotating the worktable 2 in sections and / or moving the power head, the advantages of dual-station parallel machining can be extended to any number of machining positions, rather than being limited to a single machining operation. When the worktable 2 rotates in sections and the power head moves simultaneously, the worktable 2 provides a wide range of angular indexing, while the power head provides a small range of linear compensation. Together, they can cover the entire area to be machined on the workpiece 3.

[0030] For large, thin-walled parts, such as large gear rings, the radial stiffness is often limited. When two power heads mill workpiece 3 simultaneously in opposite directions or at a certain angle along its diameter, the direction and magnitude of the resultant force of the two milling forces will change dynamically, causing instantaneous elastic deformation of workpiece 3 in the horizontal plane, affecting the dimensional accuracy and relative positional accuracy of the two machining positions.

[0031] Therefore, when machining a set of circumferential array features, the machining positions of the two power heads are always 180 degrees apart, with one power head milling in a clockwise direction and the other power head milling in a counterclockwise direction.

[0032] The two power heads are always positioned 180 degrees apart, meaning they are always at opposite ends of the workpiece 3's diameter. Simultaneously, one power head mills clockwise, and the other mills counter-clockwise. Here, "clockwise" and "counter-clockwise" refer to the feed direction of the milling cutter relative to the workpiece 3. By setting opposite feed directions, a pair of mutually canceling force couples or opposing forces are formed. Specifically, assuming workpiece 3 is a ring, when milling clockwise at the 0-degree position, the radial component of the cutting force points towards the center; when milling counter-clockwise at the 180-degree position, the radial component of the cutting force also points towards the center. The two forces are similar in magnitude and opposite in direction, significantly reducing the actual resultant force acting on workpiece 3. If the two milling directions are the same, the radial forces both point towards the center, resulting in a resultant force that is twice as strong, easily causing the ring to shrink and deform inward. This method converts the harmful radial resultant force into an internal force, ensuring the workpiece 3 maintains shape stability during machining.

[0033] In another scenario, when the quantity, type, and location of the structures to be processed are unevenly distributed, in dual-station parallel processing, simply dividing the tasks according to left and right areas can lead to one power head not completing its processing while the other becomes idle prematurely. For example, workpiece 3 has 10 deep holes on the left side and only 2 shallow grooves on the right side. The left power head takes longer to process, while the right power head finishes early and waits, so the overall efficiency is not doubled.

[0034] Based on this, when the number, type, or location of the structures to be processed is unevenly distributed, a task allocation step is also included: decompose the workpiece 3 processing program into multiple processing elements, each processing element corresponding to one continuous cutting process; extract the processing position, processing type, and estimated processing time of each processing element; arrange all processing elements in descending order of estimated processing time, and sequentially allocate each processing element to the one with the shorter current cumulative estimated processing time among the two power heads. If the cumulative estimated processing time of the first power head is less than or equal to the cumulative estimated processing time of the second power head, the processing element is allocated to the first power head; otherwise, it is allocated to the second power head; check whether the processing elements in the task list of each power head after allocation are within the reachable range of that power head. If they are outside the reachable range, the processing element is forcibly allocated to another power head.

[0035] A machining element is the smallest indivisible machining action in a machining program, such as drilling a hole, milling a groove, or turning an outer diameter. Decomposing a complete workpiece machining program into machining elements is equivalent to breaking down a large task into many smaller tasks. Machining position refers to the X, Y, and Z coordinate values ​​in the workpiece's coordinate system. Machining types include drilling, milling, and turning outer diameters. The estimated machining time is calculated based on the machining parameters using the formula: machining path length divided by feed rate, plus the auxiliary time required for tool changes or positioning.

[0036] Since large processing elements have a significant impact on the total time, early allocation can prevent severe imbalances at the end. Therefore, all processing elements are sorted from largest to smallest according to their estimated processing time, and the processing element with the largest current processing time is selected and allocated to the power head with the shortest current cumulative time. The specific comparison logic is as follows: the cumulative times of the two power heads are set as TA and TB, initially 0. For each processing element, if TA ≤ TB, it is allocated to power head A, and TA is updated to TA + the estimated time of the processing element; otherwise, it is allocated to power head B, and TB is updated to TB + the estimated time of the processing element.

[0037] After allocation, accessibility constraints need to be checked. Each power head has its own X, Y, and Z axis travel limits. If the position coordinates of a machining element exceed the travel range of the corresponding power head, that machining element cannot be processed by that power head. In this case, the system forcibly allocates the machining element to another power head.

[0038] By using time-based balanced allocation, the total processing time of the two power heads is made essentially the same, reducing waiting time and improving equipment utilization. Accessibility checks ensure the physical feasibility of the allocation scheme, avoiding situations where theoretical balance is achieved but actual processing is impossible.

[0039] The estimated machining time is calculated based on the cutting depth, feed rate, spindle speed, and machining path length corresponding to the machining element.

[0040] In a CNC system, each machining element has corresponding machining parameters, which are typically specified in the machining program using G-codes. For example, G01 X100 Y50 F200 indicates linear feed at a feed rate of 200 mm / min. The depth of cut in layered machining is determined by the Z-axis feed rate. The spindle speed is specified by S-codes. The machining path length can be calculated by parsing the interpolation instructions in the machining program.

[0041] In specific calculations, for linear interpolation, the machining time equals the path length divided by the feed rate. For circular interpolation, the arc length is divided by the tangential feed rate. Additionally, auxiliary times need to be considered, such as rapid positioning time, tool change time, and coolant switching time. These auxiliary times can be obtained empirically from machine tool parameters. When machining involves multiple repetitions of the same action, the time for a single hole can be estimated by multiplying the time for the hole by the number of holes.

[0042] Accurate time estimation is fundamental to achieving balanced task allocation. If the estimated time deviates too much, the actual effectiveness of the allocation will be significantly reduced. Through calculations based on processing parameters, the error between the estimated time and the actual processing time can be controlled within a reasonable range, providing a good initial condition for subsequent dynamic adjustments.

[0043] In other specific examples of this disclosure, a dynamic adjustment step is also included: recording the actual processing time of each processing element in real time during the processing; when one power head completes all processing elements in its task list, checking whether there are any unfinished processing elements in the task list of another power head; if there are, and the unfinished processing element is within the reach of the power head that has completed the task, transferring the unfinished processing element to the power head that has completed the task for execution.

[0044] In actual machining, even with initial allocation, discrepancies may still occur between estimated and actual machining times. Several factors can cause this deviation: tool wear during cutting may lead operators to reduce feed rate to protect the tool; uneven hardness within the workpiece material increases cutting resistance in certain areas; and coolant pressure fluctuations affect chip removal efficiency. These factors cannot be fully predicted during the programming phase, thus the initial allocation scheme may become unbalanced during execution, with one power head completing its task ahead of schedule while the other continues working, resulting in idle equipment.

[0045] In practice, the CNC system starts a timer for each machining element to record the actual time taken from the start to the end of cutting. After a machining element completes its work, the system compares the actual time with the estimated time and stores the data. The trigger condition is that the task list of one power head is completely cleared, at which point that power head becomes idle. The system immediately scans the task list of the other power head to see if there are any unfinished machining elements. If so, the system further determines whether the machining position coordinates of these unfinished machining elements are within the X, Y, and Z axis travel range of the idle power head. Since the two power heads are symmetrically arranged on the gantry, their travel ranges usually overlap, and the middle area of ​​workpiece 3 may be machined by both power heads. As long as the position of an unfinished machining element is within the reachable area of ​​the idle power head, the system can delete it from the task list of the unfinished machining power head and add it to the task list of the idle power head. Subsequently, the idle power head begins machining according to the newly assigned task, and the two power heads re-enter a parallel working state. This method compensates for the load imbalance caused by estimation errors and improves the overall utilization rate of the two power heads through dynamic adjustment.

[0046] The aforementioned provisions only specify that unfinished processing units can be transferred, but do not specify which processing units to transfer. If they are transferred arbitrarily, such as transferring only a very small processing unit, the idle power head will soon become idle again, while the busy power head will still take a long time, and the overall completion time will not be significantly shortened.

[0047] Therefore, in a further specific example of this disclosure, when transferring an unfinished processing element to a power head that has completed its task, the remaining processing time of the two power heads tends to be equal after the transfer.

[0048] For idle power heads, the remaining processing time is zero before the transfer; after the transfer, its remaining time equals the sum of the estimated times of the transferred processing elements. For busy power heads, the remaining time before the transfer is the sum of the estimated times of all unfinished processing elements; after the transfer, its remaining time is reduced by the time of the transferred processing elements. The goal is to minimize the difference between the two remaining times after the transfer. Before processing begins, all processing elements are globally sorted and allocated, and during processing, the remaining tasks are locally redistributed. This combination ensures that the load on the two power heads remains balanced throughout the entire processing cycle.

[0049] It is important to note that tool consistency must be considered during the transfer process. If a machining element in the optimal subset requires a different tool than the one currently in use on the idle power head, the system may need to perform an additional tool change. In this case, the tool change time should be deducted before evaluating the benefits. In practice, it is usually required that the tool magazines of both power heads be configured identically, or that commonly used tools be pre-prepared on the idle power head to reduce tool change time.

[0050] Example 2 This embodiment provides a dual-station milling-turning composite machine tool for the parallel machining method of the milling-turning composite machine tool as described in Embodiment 1. Figure 2 , Figure 3 As shown, the system includes a turntable base 1, a worktable 2, two columns 7, a crossbeam 6, a transmission mechanism, and two milling heads 4. The two columns 7 are fixed to the turntable base 1, and the crossbeam 6 is fixed to the upper ends of the two columns 7. The worktable 2 is mounted on the turntable base 1 and can rotate around a vertical axis. Each milling head 4 is mounted on the crossbeam 6 and can move laterally along the crossbeam 6. The milling head 4 includes a vertical ram 8, a horizontal ram 18, a spindle box 15, and a milling electric spindle 14. The vertical ram 8 is movably mounted on the crossbeam 6 in the vertical direction. The horizontal slide 18 is movably mounted at the lower end of the vertical slide 8 in the horizontal front-back direction. The spindle box 15 is fixed at the front end of the horizontal slide 18, and the milling and turning electric spindle 14 is mounted inside the spindle box 15. The transmission mechanism includes a Y-axis transmission mechanism 5, a Z-axis transmission mechanism 9, and an X-axis transmission mechanism 19. The Y-axis transmission mechanism 5 is used to drive the milling and turning power head 4 to move laterally along the crossbeam 6. The Z-axis transmission mechanism 9 is used to drive the vertical slide 8 to move in the vertical direction. The X-axis transmission mechanism 19 is used to drive the horizontal slide 18 to move in the horizontal front-back direction.

[0051] The rotary table base 1 is the foundation of the entire machine tool, typically constructed of cast iron, providing sufficient rigidity and vibration damping, and is directly fixed to the foundation. Two columns 7 are rigidly connected to the left and right sides of the rotary table base 1 via bolts and locating keys. The crossbeam 6 is then bolted to the upper ends of the two columns 7, forming a closed gantry frame. The worktable 2 is installed at the center of the rotary table base 1 and can rotate continuously around a vertical axis. Driven by a servo motor and equipped with an angle encoder, it can achieve positioning at any angle. The upper surface of the worktable 2 is equipped with T-slots or hydraulic clamps for clamping workpieces 3.

[0052] Two milling heads 4 are independently mounted on the front side of the crossbeam 6. Each head is connected to the crossbeam 6 via a guide rail pair and can move along the longitudinal direction (Y-axis, left-right direction) of the crossbeam 6. The Y-axis transmission mechanism 5 includes a servo motor, a coupling, and a ball screw pair, which drives the head to move laterally. Each head has its own Y-axis transmission mechanism 5, so the lateral movement of the two heads is independent.

[0053] The vertical ram 8 is a cuboid component mounted on the transverse slide 10 on the crossbeam 6 via guide rails, and can move up and down in the vertical direction (Z-axis). The Z-axis transmission mechanism 9 drives the vertical ram 8 to rise and fall. At the lower end of the vertical ram 8, a horizontal ram 18 is installed, which can move in the horizontal forward-backward direction (X-axis), perpendicular to the longitudinal direction of the crossbeam 6, i.e., perpendicular to the gantry, commonly referred to as the forward-backward direction. The X-axis transmission mechanism 19 drives the horizontal ram 18 to move forward and backward. The spindle box 15 is fixed to the front end face of the horizontal ram 18, and the milling / turning electric spindle 14 is installed inside the spindle box 15, with its axis vertically downward. The milling / turning electric spindle 14 is an AC servo spindle capable of both low-speed, high-torque turning and high-speed milling. When a turning tool is installed, the spindle is de-energized and locked by a hydraulic mechanism to prevent accidental spindle rotation during turning; when a milling cutter is installed, the spindle rotates, and the speed can be controlled by a program.

[0054] Traditional machine tools typically only have Y and Z axes, with the X axis replaced by the rotation of the worktable 2. This machine tool has three independent linear axes 4 for each milling head 4, enabling three-axis linkage. This allows each head to move independently during milling, while the worktable 2 only rotates during indexing and remains stationary during the milling process.

[0055] Both power heads of this machine tool can perform turning and milling, achieving true dual-station parallel machining and improving efficiency. During milling, the worktable 2 is stationary, and feed is completed by high-precision linear axes (X, Y, Z), avoiding the low-precision problem of the large rotary worktable 2; at the same time, driving the small-mass ram saves a lot of energy compared to driving the large-mass worktable 2. In addition, since each power head can perform three-axis linkage, it can independently process structures with different trajectories, thus enabling the simultaneous processing of circular arrays, mirror arrays, and even features with completely different shapes.

[0056] In this embodiment, the transmission mechanism typically employs a ball screw combined with a servo motor, with precision bearings supporting both ends of the screw. The guide rails utilize heavy-duty roller linear guides or sliding guides to meet the cutting force requirements of large parts. The vertical slide 8 and horizontal slide 18 are made of high-strength cast iron or steel, and are internally reinforced.

[0057] In some other specific examples of this disclosure, each milling head 4 further includes a transverse slide 10, a slide plate 11, a horizontal slide 13, and a slide plate 17; the transverse slide 10 is disposed on the crossbeam 6, the slide plate 11 and the transverse slide 10 form a guide space, the vertical slide 8 is installed in the guide space and can slide in the vertical direction; the horizontal slide 13 is fixed to the lower end face of the vertical slide 8, the slide plate 17 and the horizontal slide 13 together form a guide space, the horizontal slide 18 is installed in the guide space and can slide in the horizontal front-back direction.

[0058] To enable the vertical movement of the vertical slide block 8, a transverse slide table 10 is provided at the corresponding position of each power head on the crossbeam 6. The transverse slide table 10 cooperates with the guide rail on the crossbeam 6 and can move left and right. The transverse slide table 10 serves as the mounting base for the vertical slide block 8, and the slide table pressure plate 11 is fixed to the transverse slide table 10 by bolts, together with the transverse slide table 10 forming a rectangular or dovetail-shaped guide space. The vertical slide block 8 is installed in this guide space and can slide up and down along the direction defined by the slide table pressure plate 11.

[0059] For horizontal movement, a horizontal slide block 13 is bolted to the lower end of the vertical slide block 8. The slide block pressure plate 17 and the horizontal slide block 13 also form a guide space, in which the horizontal slide block 18 is installed and can slide in the horizontal back-and-forth direction. One end of the horizontal slide block 18 protrudes, and the spindle box 15 is installed at the front end.

[0060] In a specific example disclosed herein, a first cylindrical pin 12 and a second cylindrical pin 16 are also included. The first cylindrical pin 12 is disposed between the vertical slide block 8 and the horizontal slide block 13 for positioning connection, and the second cylindrical pin 16 is disposed between the horizontal slide block 18 and the spindle box 15 for positioning connection.

[0061] During machine tool assembly, it is necessary to ensure the relative positional accuracy between multiple components. For example, the moving direction (X-axis) of the horizontal slide 13 should maintain a high-precision perpendicular relationship with the moving direction (Y-axis) of the crossbeam 6, while the spindle axis should be perpendicular to both the X and Y axes.

[0062] Cylindrical pin positioning results in higher geometric accuracy of the assembled machine tool, which can be maintained over a long period. Relying solely on bolt connections makes precise positioning difficult due to bolt hole clearance and bolt elastic deformation; furthermore, bolts may loosen under heavy cutting, leading to loss of accuracy. The addition of cylindrical pins provides an extra locating surface, distributing shear force, requiring only the bolts to provide preload.

[0063] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A parallel machining method for a milling-turning machine tool, characterized in that, The milling and turning machine tool includes a horizontal worktable and two vertical power heads, and the parallel machining method includes: During turning, both power heads are equipped with cutting tools. At this time, the worktable rotates, and the two cutting tools are set with different cutting depths to simultaneously turn the workpiece. During milling, both power heads are equipped with milling cutters. At this time, the worktable is stationary, and the two power heads are independently linked in three axes. Each milling cutter can move according to its own machining trajectory. The two milling cutters simultaneously mill the structure at different positions on the workpiece. The worktable is only used for positioning and indexing. The worktable is locked during the milling process. When the number, type, or location of the structures to be processed are unevenly distributed, a task allocation step is also included: The workpiece machining program is decomposed into multiple machining elements, each corresponding to a continuous cutting process; the machining position, machining type, and estimated machining time of each machining element are extracted. Arrange all processing elements in descending order of estimated processing time. Assign each processing element to the power head with the shorter current cumulative estimated processing time. If the cumulative estimated processing time of the first power head is less than or equal to the cumulative estimated processing time of the second power head, assign the processing element to the first power head; otherwise, assign it to the second power head. Check whether the processing elements in the task list of each power head after assignment are within the reachable range of that power head. If they are outside the reachable range, forcibly assign the processing element to the other power head.

2. The parallel machining method of the milling-turning composite machine tool as described in claim 1, characterized in that, When multiple positions need to be milled, the structure at two positions is milled simultaneously while the worktable is stationary. After the structure at these two positions is completed, the worktable rotates and / or the power head moves to the next working position, and the two power heads continue to mill simultaneously.

3. The parallel machining method of the milling-turning composite machine tool as described in claim 1, characterized in that, When machining a set of circular array features, the machining positions of the two power heads are always 180 degrees apart, with one power head milling in a clockwise direction and the other power head milling in a counterclockwise direction.

4. The parallel machining method of the milling-turning composite machine tool as described in claim 1, characterized in that, The estimated machining time is calculated based on the cutting depth, feed rate, spindle speed, and machining path length corresponding to the machining element.

5. The parallel machining method of the milling-turning composite machine tool as described in claim 1, characterized in that, It also includes dynamic adjustment steps: The actual processing time of each processing element is recorded in real time during the processing process; Once one power head has completed all the processing elements in its task list, it checks whether there are any unfinished processing elements in the task list of another power head. If so, and the unfinished processing element is within the reach of the power head that has completed the task, the unfinished processing element is transferred to the power head that has completed the task for execution.

6. The parallel machining method of the milling-turning composite machine tool as described in claim 5, characterized in that, When transferring unfinished processing elements to power heads that have completed their tasks, the remaining processing time of the two power heads should be made to be equal after the transfer.

7. A dual-station milling-turning machine tool for a parallel machining method of a milling-turning machine tool as described in any one of claims 1-6, characterized in that, It includes a turntable base, a worktable, two columns, a crossbeam, a transmission mechanism, and two milling heads; Two columns are fixed to the turntable base, and a crossbeam is fixed to the upper end of the two columns. The worktable is installed on the turntable base and can rotate around the vertical axis. Each milling head is mounted on a crossbeam and can move laterally along the crossbeam. The milling head includes a vertical ram, a horizontal ram, a headstock, and a milling spindle. The vertical ram is mounted on the crossbeam and can move vertically. The horizontal ram is mounted at the lower end of the vertical ram and can move horizontally back and forth. The headstock is fixed at the front end of the horizontal ram, and the milling spindle is installed inside the headstock. The transmission mechanism includes a Y-axis transmission mechanism, a Z-axis transmission mechanism, and an X-axis transmission mechanism. The Y-axis transmission mechanism is used to drive the milling head to move laterally along the crossbeam, the Z-axis transmission mechanism is used to drive the vertical slide to move vertically, and the X-axis transmission mechanism is used to drive the horizontal slide to move horizontally forward and backward.

8. The dual-station milling and turning composite machine tool as described in claim 7, characterized in that, Each milling head also includes a transverse slide, a slide plate, a horizontal slide, and a slide plate; The transverse slide is set on the crossbeam, and the slide pressure plate and the transverse slide form a guide space. The vertical slide is installed in the guide space and can slide in the vertical direction. The horizontal slide block is fixed to the lower end face of the vertical slide block. The slide block pressure plate and the horizontal slide block together form a guide space. The horizontal slide block is installed in this guide space and can slide in the horizontal back-and-forth direction.

9. The dual-station milling and turning composite machine tool as described in claim 8, characterized in that, It also includes a first cylindrical pin and a second cylindrical pin. The first cylindrical pin is set between the vertical slide block and the horizontal slide block for positioning and connection, and the second cylindrical pin is set between the horizontal slide block and the spindle box for positioning and connection.

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