High-efficiency mirror image milling method for integral box bottom with super-multiple closed grids

Abstract

The invention provides an efficient mirror image milling method for an integral box bottom with multiple closed grids. The efficient mirror image milling method is suitable for continuous machining of the integral box bottom with the multiple closed grids. The method comprises the following steps: firstly, moving a milling side and a measuring side to a safety position, and quickly moving the milling side to a cutter feeding position; then, measuring side compensation feed is started to the initial cutting point, and then milling side compensation feed is started to the cutting point; and after the cutting of the area is completed, the milling side is closed to compensate the cutter lifting. And the measuring side moves to the initial point of the next area with compensation, and the milling side moves to the feed point without compensation. And milling side compensation feed cutting is started, and the process is repeated until all the areas are completed. And finally, compensation is closed, the milling side and the measuring side are lifted and retracted to the safety positions respectively, and then the milling side and the measuring side are moved to the initial position to finish machining. By finely regulating and controlling the movement of the two sides, the cutter feeding and retracting actions are greatly reduced, and the mirror image milling machining efficiency of the super-multi-closed-grid integral box bottom is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of numerical control machining, and in particular to a highly efficient mirror image milling method for an overall box bottom with a large number of closed grids. Background Art

[0002] Mirror milling technology has been widely used in the processing of integral tank bottom products. Because it has the function of online measurement and compensation of wall thickness, it can control the wall thickness within an ideal range. It has now become an important technology in the processing of the bottom products of my country's new generation of launch vehicle tanks. The traditional mirror milling method performs well when processing the bottom of the tank containing a small amount of closed areas, but its limitations are gradually emerging when facing the integral bottom of the new launch vehicle fuel tank.

[0003] With the launch of the development of new models such as reusable rockets, the design requirements for the overall bottom of the box have become increasingly complex. In order to strengthen the overall bottom of the box, multiple reinforcing ribs were added to the outer surface of the overall bottom of the box, resulting in the formation of numerous (nearly a thousand) closed lightening grids on the outer surface of the overall bottom of the box. These closed grids cannot be connected to each other through the cutting tool path, which brings unprecedented challenges to the mirror milling process.

[0004] A patent document with publication number CN115647744A discloses a method for precision machining of wall thickness of an integral box bottom with an ultra-large diameter-to-thickness ratio, which relates to the field of storage tank machining, including: clamping the box bottom, taking the horizontal reference line of the box bottom blank as a reference, turning the inner surface of the box bottom according to the theoretical machining amount of the inner surface of the box bottom to obtain the inner surface after machining; clamping the box bottom, taking the inner surface after machining as a reference, rough turning the outer surface of the box bottom, and stopping the rough turning of the outer surface after reaching the turning allowance; heat aging the box bottom after rough turning; and milling the thin area and thick area of ​​the outer surface of the box bottom after heat aging by five-axis mirror milling.

[0005] According to the conventional mirror milling method, at least one machining program needs to be generated for each closed area. For an integral box bottom containing a large number of closed areas, the number of machining programs will be very large, which not only increases the complexity of programming, but also brings many inconveniences to production and processing. In addition, the feed and retract speed of each machining program is relatively slow, usually less than one-tenth of the normal cutting speed, to ensure the safety of feed and retract. Therefore, when machining an integral box bottom containing a large number of closed areas, the feed and retract time occupies a large part of the total machining time, seriously affecting the machining efficiency.

[0006] In summary, it is urgent to propose a new processing method for the mirror milling of the overall box bottom with a large number of closed grids, so as to greatly reduce the number of programs, reduce the feed and retract time, and improve the processing efficiency. Summary of the invention

[0007] In view of the defects in the prior art, the object of the present invention is to provide a highly efficient mirror image milling method for an integral box bottom with a large number of closed grids.

[0008] According to the present invention, a method for efficient mirror milling of a multi-closed grid integral box bottom is provided, the method comprising the following steps:

[0009] Initial tool moving steps: the milling side and the measuring side are moved to the safe position respectively, and the milling side is moved to the feed position;

[0010] Initial feed steps: After turning on the measuring side compensation function, feed to the initial cutting point position of the inner surface, then turn on the milling side compensation function, and feed the milling side to the cutting point position in oblique lines and straight lines;

[0011] Cutting process steps: Use mirror milling motion to complete area processing;

[0012] Steps for lifting the tool between areas: After turning off the milling side compensation function, lift the tool along the axial direction on the milling side to set the height;

[0013] Steps for tool movement between areas: The measuring side moves along the inner surface to the initial milling point of the next closed area with compensation function, and the milling side moves to the feed point of the next area according to the set tool lift height without compensation mode;

[0014] Inter-area feed step: After the milling side compensation function is turned on, the milling side feeds to the cutting point, and then the cutting movement is performed. If there are multiple closed areas, the cutting process steps are repeated until the inter-area feed step;

[0015] Final tool retraction step: After processing the last area, turn off the milling side compensation function, lift the tool axially on the milling side to the set height, then turn off the measuring side compensation function, and retract the tool axially on the measuring side to a safe height;

[0016] Final tool moving step: lift the tool to a safe height on the milling side, move the measuring side to the initial position, and then move the milling side to the initial position, and the processing is completed.

[0017] Preferably, in the initial tool moving step, after the milling side and the measuring side are respectively moved from the initial positions defined by the equipment to the safe positions of the first area, the milling side alone moves to the tool feed position of the first area.

[0018] Preferably, in the initial feed step, the measuring side compensation function is first turned on, the feed speed is less than 100 mm / min, and the measuring side slowly feeds from the safe position of the first area to the measuring position of the first area. The measuring side compensation function enables the measuring side to maintain a fixed distance from the inner surface; after obtaining stable measured wall thickness data, the milling side compensation function is turned on, and the milling side slowly feeds from the feed position of the first area to the initial cutting position of the first area. The feed speed is less than 100 mm / min. During the process, the milling side compensation algorithm monitors the wall thickness in real time until the wall thickness reaches the set value.

[0019] Preferably, in the cutting process step, according to the set wall thickness compensation algorithm, the milling side and the measuring side are driven by the mirror milling process trajectory to synchronously complete the milling process of the first area, and the milling speed is not less than 5000 mm / min.

[0020] Preferably, in the step of lifting the tool between areas, the milling side compensation function is first turned off, and then the milling side is lifted axially to the set height of the first area, and the tool lifting speed is 5000mm / min.

[0021] Preferably, in the step of moving the tool between areas, the measuring side moves along the inner surface to the initial measuring point of the second area at the cutting speed with the compensation function, and the compensation function controls the measurement side to maintain a fixed distance from the inner surface during the movement; the milling side moves to the feed point of the second area at the cutting speed according to the set tool lift height with the compensation function turned off.

[0022] Preferably, in the inter-area feed step, after the milling side compensation function is turned on, the milling side feeds from the feed point of the second area to the initial cutting point of the second area, and the feed speed is less than 100 mm / min. After completing the feed movement, the cutting movement is performed.

[0023] Preferably, in the final retraction step, after processing the last area, first turn off the milling side compensation function, retract the milling side axially to the set height, and use the cutting speed for the retraction speed; then turn off the measuring side compensation function, retract the measuring side normally to a safe height, and use the cutting speed for the retraction speed.

[0024] Preferably, in the final tool moving step, the milling side uses a rapid moving speed to lift the tool to a safe height, and after the measuring side moves to the initial position, the milling side uses a rapid moving speed to move to the initial position, and the processing is completed.

[0025] Preferably, the integral box bottom is an integral box bottom of a launch vehicle fuel tank with a smooth and featureless inner surface and a closed cavity on the outer surface, and the processing trajectory is a path including multiple closed areas.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention significantly reduces the number of programs required for the mirror milling of the entire bottom of a box with multiple closed grids by merging the processing programs of multiple closed areas into one processing program; it not only simplifies the processing flow, but also improves the processing efficiency and reduces the complexity of program management and execution;

[0028] 2. The present invention eliminates the advance and retreat action on the measuring side between closed areas and reduces the advance and retreat height on the milling side, thereby achieving a safe and efficient transition between areas; effectively reducing the extra processing time caused by the advance and retreat action, further improving the overall processing efficiency;

[0029] 3. The efficient mirror image milling processing method for the overall box bottom with multiple closed grids provided by the present invention provides a solid process foundation for the subsequent optimization of the overall box bottom structure; by achieving efficient and precise processing, it provides strong support for the manufacture of key components such as launch vehicle fuel tanks, and helps to promote the sustainable development and progress of aerospace technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0031] Figure 1 It is a schematic flow chart of the highly efficient mirror image milling processing method for the overall box bottom with multiple closed grids of the present invention;

[0032] Figure 2 This is a schematic diagram of the overall box bottom structure of a multi-closed grid according to the present invention;

[0033] Figure 3 It is a schematic diagram of the positions of the milling side and the compensation side of the efficient mirror milling processing of the ultra-multiple closed grid integral box bottom of the present invention.

[0034] in:

[0035] Overall box bottom section 1 First area milling side cutting position 14

[0036] Overall box bottom inner profile 2 First area measurement side end position 15

[0037] Overall box bottom thickening area 3 First area milling side cutting end position 16

[0038] The first thinning area of ​​the overall box bottom 4 The first area milling side is set to the raised position 17

[0039] The second thinning area of ​​the overall box bottom 5 The starting position of the second area measurement side 18

[0040] Mirror milling device measuring side 6 Second area milling side setting raised position 19

[0041] Measuring side initial position 7 Second area milling side infeed position 20

[0042] Mirror milling machine milling side 8 Second area milling side cutting position 21

[0043] Milling side initial position 9 Second area measuring side end position 22

[0044] Measuring side safety position 10 Second area cutting side end position 23

[0045] First area measuring side starting position 11 Second area cutting side end setting raising position 24

[0046] Milling side safety position 12 Machining end measuring side safety position 25

[0047] Milling side feed position 13 Machining end milling side safety position 26 DETAILED DESCRIPTION

[0048] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0049] Embodiment 1:

[0050] According to the present invention, a method for efficient mirror milling of a multi-closed grid integral box bottom is provided, the method comprising the following steps:

[0051] Initial tool moving steps: the milling side and the measuring side are moved to the safe position respectively, and the milling side is moved to the feed position;

[0052] Initial feed steps: After turning on the measuring side compensation function, feed to the initial cutting point position of the inner surface, then turn on the milling side compensation function, and feed the milling side to the cutting point position in oblique lines and straight lines;

[0053] Cutting process steps: Use mirror milling motion to complete area processing;

[0054] Steps for lifting the tool between areas: After turning off the milling side compensation function, lift the tool along the axial direction on the milling side to set the height;

[0055] Steps for tool movement between areas: The measuring side moves along the inner surface to the initial milling point of the next closed area with compensation function, and the milling side moves to the feed point of the next area according to the set tool lift height without compensation mode;

[0056] Inter-area feed step: After the milling side compensation function is turned on, the milling side feeds to the cutting point, and then the cutting movement is performed. If there are multiple closed areas, the cutting process steps are repeated until the inter-area feed step;

[0057] Final tool retraction step: After processing the last area, turn off the milling side compensation function, lift the tool axially on the milling side to the set height, then turn off the measuring side compensation function, and retract the tool axially on the measuring side to a safe height;

[0058] Final tool moving step: lift the tool to a safe height on the milling side, move the measuring side to the initial position, and then move the milling side to the initial position, and the processing is completed.

[0059] In the initial tool moving step, the milling side and the measuring side are moved from the initial position defined by the machine to the safe position of the first area, and then the milling side moves alone to the feed position of the first area.

[0060] In the initial feed step, the measuring side compensation function is first turned on, the feed speed is less than 100mm / min, and the measuring side slowly feeds from the safe position of the first area to the measuring position of the first area. The measuring side compensation function enables the measuring side to maintain a fixed distance from the inner surface; after obtaining stable measured wall thickness data, the milling side compensation function is turned on, and the milling side slowly feeds from the feed position of the first area to the initial cutting position of the first area. The feed speed is less than 100mm / min. During the process, the milling side compensation algorithm monitors the wall thickness in real time until the wall thickness reaches the set value.

[0061] In the cutting process step, according to the set wall thickness compensation algorithm, the mirror milling trajectory drives the milling side and the measuring side to synchronously complete the milling of the first area, and the milling speed is not less than 5000mm / min.

[0062] In the step of lifting the tool between areas, first turn off the milling side compensation function, then lift the tool axially on the milling side to the set height of the first area, and the tool lifting speed is 5000mm / min.

[0063] In the step of moving the tool between areas, the measuring side moves along the inner surface to the initial measuring point of the second area at the cutting speed with the compensation function. During the movement, the compensation function controls the fixed distance from the inner surface. When the compensation function is turned off, the milling side moves to the feed point of the second area at the cutting speed according to the set tool lift height.

[0064] In the inter-area feed step, after the milling side compensation function is turned on, the milling side feeds from the feed point of the second area to the initial cutting point of the second area, and the feed speed is less than 100 mm / min. After completing the feed movement, the cutting movement is performed.

[0065] In the final retraction step, after machining the last area, first turn off the milling side compensation function, and retract the milling side axially to the set height, using the cutting speed for the retraction speed; then turn off the measuring side compensation function, and retract the measuring side normally to the safe height, using the cutting speed for the retraction speed.

[0066] In the final tool moving step, the milling side uses a rapid moving speed to lift the tool to a safe height. After the measuring side moves to the initial position, the milling side uses a rapid moving speed to move to the initial position, and the processing is completed.

[0067] The integral bottom of the fuel tank of a launch vehicle has a smooth and featureless inner surface and a closed cavity on the outer surface. The processing trajectory is a path containing multiple closed areas.

[0068] Embodiment 2:

[0069] The present invention provides a highly efficient mirror image milling processing method for an overall box bottom with multiple closed grids, which is characterized in that when a plurality of closed areas of the overall box bottom are continuously processed, the following steps are included: Step 1, initial tool shifting: the milling side and the measuring side are respectively moved to a safe position, and the milling side is quickly moved to a feed position; Step 2, initial feed: after the measuring side compensation function is turned on, the tool is fed to the initial cutting point position of the inner surface, and then the milling side compensation function is turned on, and the milling side is divided into oblique lines and straight lines to feed to the cutting point position; Step 3, cutting processing: completing the mirror image milling processing of the area; Step 4, tool lifting between areas: after the milling side compensation function is turned off, the milling side is lifted axially to set a height; Step 5, tool shifting between areas: the measuring side is moved with the compensation function If possible, move along the inner surface to the initial milling point of the next closed area. The milling side moves to the feed point of the next area according to the set tool lifting height in the mode without compensation; Step 6, inter-area feed: After turning on the milling side compensation function, the milling side feeds to the cutting point, and then performs cutting movement. If there are multiple closed areas, repeat steps 3 to 6; Step 7, final tool withdrawal: After processing the last area, turn off the milling side compensation function, axially lift the milling side to the set height, and then turn off the measuring side compensation function, and axially withdraw the measuring side to a safe height; Step 8, final tool movement: The milling side lifts the tool to a safe height, and after the measuring side moves to the initial position, the milling side moves to the initial position, and the processing ends. The high-efficiency mirror image milling processing method of the overall box bottom with multiple closed grids of the present invention significantly reduces the feed and retract movement of the measuring side and reduces the feed and retract movement distance of the milling side by reasonably controlling the movement of the milling side and the measuring side at different stages, thereby greatly improving the mirror image milling processing efficiency of the overall box bottom with multiple closed grids.

[0070] The present invention provides a highly efficient mirror milling method for an overall box bottom with multiple closed grids, comprising the following steps:

[0071] Step 1: Initial tool movement: The milling side and the measuring side are moved to safe positions respectively, and the milling side is quickly moved to the feed position;

[0072] Step 2, initial feed: After turning on the measuring side compensation function, feed to the initial cutting point position of the inner surface, then turn on the milling side compensation function, and feed the milling side to the cutting point position in oblique lines and straight lines;

[0073] Step 3: Cutting: Use mirror milling motion to complete the area processing;

[0074] Step 4: Lift the tool between areas: After turning off the milling side compensation function, lift the tool along the axial direction of the milling side to set the height;

[0075] Step 5: Tool movement between areas: The measuring side moves along the inner surface to the initial milling point of the next closed area with compensation function, and the milling side moves to the feed point of the next area according to the set tool lift height without compensation mode;

[0076] Step 6, inter-area feed: After the milling side compensation function is turned on, the milling side feeds to the cutting point, and then the cutting movement is performed. If there are multiple closed areas, repeat steps 3 to 6;

[0077] Step 7, final tool retraction: After processing the last area, turn off the milling side compensation function, lift the tool axially on the milling side to the set height, then turn off the measuring side compensation function, and retract the tool axially on the measuring side to a safe height;

[0078] Step 8: Final tool movement: The milling side lifts the tool to a safe height, the measuring side moves to the initial position, and the milling side moves to the initial position, and the processing is completed.

[0079] The integral bottom of a launch vehicle fuel tank has a smooth and featureless inner surface and a large number of closed cavities on the outer surface. The machining trajectory is a path containing multiple (not less than 2) closed areas.

[0080] In step 1, the milling side and the measuring side move from the initial position defined by the device to the safe position of the first area respectively, and then the milling side moves rapidly to the infeed position of the first area alone.

[0081] In step 2, the measuring side compensation function is first turned on, the feed speed is less than 100 mm / min, and the measuring side slowly feeds from the safe position of the first area to the measuring position of the first area. The measuring side compensation function enables the measuring side to maintain a fixed distance from the inner surface to avoid the inability to stably measure the wall thickness due to too large a distance, or the measuring side colliding with the inner surface due to too small a distance. After obtaining stable measured wall thickness data, the milling side compensation function is turned on. The milling side slowly feeds from the feed position of the first area to the initial cutting position of the first area, and the feed speed is less than 100 mm / min. During the process, the milling side compensation algorithm monitors the wall thickness in real time until the wall thickness reaches the set value.

[0082] In step 3, according to the set wall thickness compensation algorithm, the milling side and the measuring side are driven by the mirror milling trajectory to synchronously complete the milling of the first area. The milling speed is generally not less than 5000mm / min.

[0083] In step 4, first turn off the milling side compensation function, and then lift the tool axially on the milling side to the set height of the first area. The tool lifting speed is generally 5000mm / min.

[0084] In step 5, the measuring side moves along the inner surface to the initial measuring point of the second area at the cutting speed with the compensation function. During the movement, the compensation function controls the measurement side to maintain a fixed distance from the inner surface. The milling side moves to the feed point of the second area at the cutting speed according to the set tool lift height with the compensation function turned off.

[0085] In step 6, after the milling side compensation function is turned on, the milling side feeds from the feed point of the second area to the initial cutting point of the second area, and the feed speed is less than 100mm / min. After the feed movement is completed, the cutting movement is performed. If there are multiple closed areas, repeat steps 3 to 6 until all areas are cut.

[0086] In step 7, after processing the last area, first turn off the milling side compensation function, and retract the tool axially on the milling side to the set height, using the cutting speed for the retraction speed; then turn off the measuring side compensation function, and retract the tool normally on the measuring side to a safe height, using the cutting speed for the retraction speed.

[0087] In step 8, the milling side uses a rapid moving speed to lift the tool to a safe height. After the measuring side moves to the initial position, the milling side uses a rapid moving speed to move to the initial position. The processing is now completed.

[0088] The present invention combines multiple closed area processing programs and outputs them into one processing program, thereby greatly reducing the number of programs for the mirror milling processing of the overall box bottom with a large number of closed areas; by canceling the measurement side feed and retract between closed areas and lowering the feed and retract height on the milling side, and realizing a safe transition between areas, the increase in processing time caused by the feed and retract is reduced; through this method, efficient mirror milling processing of the overall box bottom with a large number of closed areas can be realized, providing a process basis for subsequent optimization of the overall box bottom structure.

[0089] Figure 1 It is a schematic flow chart of the highly efficient mirror image milling processing method for the overall box bottom with multiple closed grids of the present invention. Figure 2 It is the main applicable object of the present invention, a schematic diagram of the overall box bottom with a large number of closed grids, whose inner surface is smooth and featureless, and the outer surface has many closed features. Figure 3 It is a schematic diagram of the positions of the milling side and the compensation side of the efficient mirror milling processing of the ultra-multiple closed grid integral box bottom of the present invention.

[0090] A partial schematic diagram of the overall box bottom 1 with many closed grids is shown in Figure 3 As shown in , the inner surface 2 is smooth and featureless, and the outer surface 3 has a large number of closed areas, including the first closed area 4 and the second closed area 5.

[0091] The present invention provides a method for efficiently mirroring a multi-closed grid integral box bottom, such as Figure 1 As shown in , it includes the following steps:

[0092] Step 1, initial tool shifting: The measuring side 6 and the milling side 7 of the mirror milling device are located at the measuring side initial position 8 and the milling side initial position 9 defined by the device respectively. During the initial tool shifting, the measuring side quickly moves to the measuring side safety position 10, the milling side quickly moves to the milling side safety position 11, and then the milling side quickly moves to the first area milling side feed position 12.

[0093] Step 2, initial feed: After turning on the measuring side compensation function, the measuring side feeds slowly (feed speed ≤ 100 mm / min) to the initial cutting point position 13 of the inner surface, and then turns on the milling side compensation function, and the milling side feeds to the first area milling side cutting position 14;

[0094] Step 3, cutting processing: Use mirror milling motion to complete the processing of the first area. At this time, the measuring side moves to the measurement end position 15 of the first area according to the trajectory, and the milling side moves synchronously to the milling end position 16 of the first area according to the trajectory;

[0095] Step 4, lifting the tool between areas: After turning off the milling side compensation function, the milling side lifts the tool along the axial direction to set the height, and reaches the first area milling side to set the lifting position 17;

[0096] Step 5, tool movement between areas: the measuring side moves along the inner surface to the starting position 18 of the measuring side of the second area with the compensation function, and the milling side moves to the set lifting position 19 of the milling side of the second area according to the set tool lifting height in the mode without compensation;

[0097] Step 6, inter-area feed: After the milling side compensation function is turned on, the milling side feeds to the second area milling side feed position 20, and then feeds slowly to the second area milling side cutting position 21, and then performs cutting motion. After the second area is processed, the measuring side reaches the second area measuring side end position 22, and the milling side reaches the second area cutting side end position 23;

[0098] Step 7, final tool retraction: After processing the second area, turn off the milling side compensation function, lift the tool axially on the milling side to the second area cutting side end set lifting position 24, then turn off the measuring side compensation function, and retract the tool axially on the measuring side to the measuring side safety position 25 after processing;

[0099] Step 8, final tool movement: lift the tool on the milling side to the safe position 26 on the milling side at the end of processing. After the measuring side moves to the initial position, the milling side moves to the initial position, and the processing is completed.

[0100] The method for efficiently mirror-image milling of the overall box bottom with multiple closed grids of the present invention combines multiple closed area processing programs and outputs them into one stage of processing, thereby greatly reducing the number of programs for the mirror-image milling of the overall box bottom with multiple closed areas. By canceling the measuring side feed and retract between closed areas and lowering the feed and retract height on the milling side, and realizing a safe transition between areas, efficient mirror-image milling of the overall box bottom with multiple closed areas is realized, providing a process basis for subsequent optimization of the overall box bottom structure.

[0101] Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0102] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0103] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A highly efficient mirror milling method for a multi-closed grid overall box bottom, characterized in that: The method comprises the following steps: Initial tool moving steps: the milling side and the measuring side are moved to the safe position respectively, and the milling side is moved to the feed position; Initial feed steps: After turning on the measuring side compensation function, feed to the initial cutting point position of the inner surface, then turn on the milling side compensation function, and feed the milling side to the cutting point position in oblique lines and straight lines; Cutting process steps: Use mirror milling motion to complete area processing; Steps for lifting the tool between areas: After turning off the milling side compensation function, lift the tool along the axial direction on the milling side to set the height; Steps for tool movement between areas: The measuring side moves along the inner surface to the initial milling point of the next closed area with compensation function, and the milling side moves to the feed point of the next area according to the set tool lift height without compensation mode; Inter-area feed step: After the milling side compensation function is turned on, the milling side feeds to the cutting point, and then the cutting movement is performed. If there are multiple closed areas, the cutting process steps are repeated until the inter-area feed step; Final tool retraction step: After processing the last area, turn off the milling side compensation function, lift the tool axially on the milling side to the set height, then turn off the measuring side compensation function, and retract the tool axially on the measuring side to a safe height; Final tool moving step: lift the tool to a safe height on the milling side, move the measuring side to the initial position, and then move the milling side to the initial position, and the processing is completed.

2. The method for high-efficiency mirror milling of a multi-closed grid integral box bottom according to claim 1 is characterized in that: In the initial tool moving step, the milling side and the measuring side are moved from the initial position defined by the machine to the safe position of the first area, and then the milling side moves alone to the feed position of the first area.

3. The high-efficiency mirror milling method for the overall box bottom with multiple closed grids according to claim 1 is characterized in that: In the initial feed step, the measuring side compensation function is first turned on, the feed speed is less than 100 mm / min, and the measuring side slowly feeds from the safe position of the first area to the measuring position of the first area. The measuring side compensation function keeps the measuring side at a fixed distance from the inner surface. After obtaining stable measured wall thickness data, the milling side compensation function is turned on. The milling side slowly feeds from the feed position of the first area to the initial cutting position of the first area. The feed speed is less than 100 mm / min. During the process, the milling side compensation algorithm monitors the wall thickness in real time until the wall thickness reaches the set value.

4. The method for high-efficiency mirror milling of a multi-closed grid integral box bottom according to claim 1, characterized in that: In the cutting process step, according to the set wall thickness compensation algorithm, the mirror milling trajectory drives the milling side and the measuring side to synchronously complete the milling of the first area, and the milling speed is not less than 5000mm / min.

5. The high-efficiency mirror milling method for the overall box bottom with multiple closed grids according to claim 1 is characterized in that: In the step of lifting the tool between areas, first turn off the milling side compensation function, then lift the tool axially on the milling side to the set height of the first area, and the tool lifting speed is 5000mm / min.

6. The high-efficiency mirror milling method for the overall box bottom with multiple closed grids according to claim 1 is characterized in that: In the step of moving the tool between areas, the measuring side moves along the inner surface to the initial measuring point of the second area at the cutting speed with the compensation function. During the movement, the compensation function controls the fixed distance from the inner surface. When the compensation function is turned off, the milling side moves to the feed point of the second area at the cutting speed according to the set tool lift height.

7. The method for high-efficiency mirror milling of a multi-closed grid integral box bottom according to claim 1, characterized in that: In the inter-area feed step, after the milling side compensation function is turned on, the milling side feeds from the feed point of the second area to the initial cutting point of the second area, and the feed speed is less than 100 mm / min. After completing the feed movement, the cutting movement is performed.

8. The method for high-efficiency mirror milling of a multi-closed grid integral box bottom according to claim 1, characterized in that: In the final retraction step, after machining the last area, first turn off the milling side compensation function, and retract the milling side axially to the set height, using the cutting speed for the retraction speed; then turn off the measuring side compensation function, and retract the measuring side normally to the safe height, using the cutting speed for the retraction speed.

9. The method for high-efficiency mirror milling of a multi-closed grid integral box bottom according to claim 1, characterized in that: In the final tool moving step, the milling side uses a rapid moving speed to lift the tool to a safe height. After the measuring side moves to the initial position, the milling side uses a rapid moving speed to move to the initial position, and the processing is completed.

10. The method for high-efficiency mirror milling of a multi-closed grid integral box bottom according to claim 1, characterized in that: The integral box bottom is an integral box bottom of a carrier rocket fuel tank with a smooth and featureless inner surface and a closed cavity on the outer surface, and the processing trajectory is a path including multiple closed areas.

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