Mirror image milling rapid positioning method and system for integrally-formed box bottom

Abstract

The invention provides an integrally-formed box bottom mirror image milling rapid positioning method and system, and the method comprises the steps: marking two through holes with a phase difference of 180 degrees on the skirt edge of the box bottom by using a lettering cutter when the inner molded surface of the integrally-formed box bottom is vertically lathed, aligning the two through holes with a through hole in the upper end surface of a clamping tool of integrally-formed box bottom mirror image milling equipment, and positioning the two through holes through a conical positioning pin; and then two centrosymmetric datum lines are arbitrarily engraved, and rapid clamping and positioning of the box bottom are achieved by calibrating the datum lines, calculating the angular deviation and correcting a machining coordinate system. The positioning precision of box bottom mirror image milling machining is improved, the technological process is optimized, and the purposes of improving the machining efficiency and reducing the production cost are achieved.

Description

Technical Field

[0001] The invention relates to the field of numerical control machining, and in particular to a method and system for rapid positioning of mirror milling of an integrally formed box bottom. Background Art

[0002] The tank bottom is an important component of the fuel tank of a launch vehicle. It is a typical thin-walled, large-size, complex curved surface part. The tank bottom has been formed by one-piece stamping. The integrally formed tank bottom with good strength and reliability has gradually replaced the traditional melon-shaped welded tank bottom. It has been used in the current models of launch vehicles. Mirror milling technology is a new generation of technology to solve the efficient and precise processing of large thin-walled parts, which realizes the precise, green and highly reliable manufacturing of the tank bottom.

[0003] The current processing of equal thickness of the whole bottom of the box can only be done by mirror milling. The diameter of the workpiece of the whole bottom of the box is usually more than 3 meters. If the clamping and correction are carried out according to the traditional machining method of the workpiece, the operator has to use the workshop crane to frequently fine-tune the position of the workpiece on the machine tool. The clamping time is too long, which is demanding on the operator, inefficient and unsafe. In addition, other processes must be carried out during the machining of the whole bottom of the box, so it is necessary to clamp and correct it on the mirror milling equipment many times. The deviation caused by repeated clamping may cause the position of the overall bottom surface features to be inaccurate, affecting the processing quality. Summary of the invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide a method and system for rapid positioning of the mirror milling of an integrally formed box bottom.

[0005] The mirror milling rapid positioning method for the integrally formed box bottom provided by the present invention comprises: Step 1: When lathing the inner surface of the integrally formed box bottom, use a carving knife to carve a circular ring line with a preset radius on the skirt edge of the box bottom; Step 2: Use a carving knife to carve quadrant lines at two positions with a phase difference of 180°, intersecting them with the circular lines in step 1 to obtain two intersection points; Step 3: Drill through holes with different diameters at the two intersections in step 2 for subsequent workpiece alignment; Step 4: Through holes of the same diameter are respectively machined at two locations on the upper end surface of the clamping fixture of the integrally formed box bottom mirror milling equipment, and the diameter value is the same as the minimum diameter value of the two through holes in step 3; Step 5: Align the holes on the fixture with the holes on the bottom of the box, insert the tapered locating pins, align the bottom of the box, and carve out two central symmetrical reference lines at any angle α between the center lines of the two through holes at the fixture position; Step 6: Use the device spindle probe to select a point on the reference line, record it as point A and point B, and calculate the angle θ between the line connecting point A and point B and the positive direction of the device Y axis;

[0006] Where X1 represents the coordinate value of the X axis of point A; X2 represents the coordinate value of the X axis of point B; Y1 represents the coordinate value of the Y axis of point A; Y2 represents the coordinate value of the Y axis of point B; Step 7: Set the angle between the center line of the two through holes at the tooling position and the positive direction of the Y axis of the equipment to β. When the bottom of the box is clamped later, the processing program is corrected by the angle deviation σ to achieve rapid clamping and positioning of the bottom of the box.

[0007] Preferably, in step 1, when the inner profile of the integrally formed box bottom is vertically turned, a circular line is engraved on the skirt edge of the box bottom with a lettering knife, the circular line is located in the plane area of ​​the skirt edge and close to the outer edge, and the engraved line depth is 0.3 mm; In step 2, at two positions with a phase difference of 180°, use a carving knife to carve quadrant lines with a length of 50 mm and a depth of 0.3 mm, which intersect with the circular line in step 1 to obtain two intersection points; In step 3, through holes with diameters of d1 and d2 are drilled at the two intersections, respectively, d1-d2=2mm, as a subsequent positioning reference.

[0008] Preferably, in step 4, the diameter value of the ring in step 1 is set to D, and through holes with a diameter equal to d2 are respectively machined at two positions with coordinate points (0, +D / 2) and (0, -D / 2) on the upper end surface of the clamping fixture of the integral forming box bottom mirror milling device; In step 5, align the holes on the fixture with the holes on the bottom of the box, insert conical locating pins with a diameter equal to d2 into the two through-hole positions, and the reference line position is the center line of the two through-holes at the fixture position rotated clockwise by a preset amplitude.

[0009] Preferably, in step 6, when taking points using the probe, the absolute values ​​of the two points in the X-axis or Y-axis direction are kept unchanged, that is, point A and point B always have the same absolute value of the X-axis coordinate or the same absolute value of the Y-axis coordinate.

[0010] Preferably, in step 7, the σ calculation expression is: After calculating the deviation σ, the machining coordinate system in the programming model is corrected in angle, a new machining program is generated, the position accuracy of the machining features is maintained, and rapid clamping and positioning of the box bottom is achieved.

[0011] The mirror milling rapid positioning system for the integrally formed box bottom provided by the present invention comprises: Module M1: When the inner surface of the integrally formed box bottom is vertically turned, a circular ring line with a preset radius is carved on the skirt edge of the box bottom with a lettering knife; Module M2: Use a carving knife to carve quadrant lines at two positions with a phase difference of 180°, which intersect with the circular lines in module M1 to obtain two intersection points; Module M3: Drill through holes with different diameters at two intersections in module M2 for subsequent workpiece alignment; Module M4: Through holes of the same diameter are machined at two locations on the upper end surface of the clamping fixture of the integrally formed box bottom mirror milling equipment. The diameter value is the same as the minimum diameter value of the two through holes in module M3; Module M5: Align the holes on the fixture with the holes on the bottom of the box, insert the tapered locating pins, align the bottom of the box, and carve two central symmetric reference lines at any angle α between the center lines of the two through holes at the fixture position; Module M6: Use the spindle probe of the equipment to select a point on the reference line, record it as point A and point B, and calculate the angle θ between the line connecting point A and point B and the positive direction of the Y axis of the equipment;

[0012] Where X1 represents the coordinate value of the X axis of point A; X2 represents the coordinate value of the X axis of point B; Y1 represents the coordinate value of the Y axis of point A; Y2 represents the coordinate value of the Y axis of point B; Module M7: Set the angle between the center line of the two through holes at the tooling position and the positive direction of the Y axis of the equipment to β. When the bottom of the box is clamped later, the processing program is corrected by the angle deviation σ to achieve rapid clamping and positioning of the bottom of the box.

[0013] Preferably, in module M1, when the inner profile of the integrally formed box bottom is vertically turned, a circular line is engraved on the skirt edge of the box bottom with a lettering knife. The circular line is located in the plane area of ​​the skirt edge and close to the outer edge, and the engraved line depth is 0.3 mm; In module M2, at two positions with a phase difference of 180°, a quadrant line with a length of 50 mm and a depth of 0.3 mm was carved with a lettering knife, intersecting with the circular line in module M1 to obtain two intersection points; In module M3, through holes with diameters of d1 and d2 are drilled at two intersections, d1-d2=2mm, as a subsequent positioning reference.

[0014] Preferably, in module M4, the diameter of the ring in module M1 is set to D, and through holes with a diameter equal to d2 are respectively machined at two positions with coordinate points (0, +D / 2) and (0, -D / 2) on the upper end surface of the clamping fixture of the integral forming box bottom mirror milling device; In module M5, align the holes on the fixture with the holes on the bottom of the box, insert conical locating pins with a diameter equal to d2 into the two through-hole positions, and the reference line position is the center line of the two through-holes at the fixture position rotated clockwise by a preset amplitude.

[0015] Preferably, in module M6, when taking points using a probe, the absolute values ​​of the two points in the X-axis or Y-axis direction are kept unchanged, that is, point A and point B always have the same absolute value of the X-axis coordinate or the same absolute value of the Y-axis coordinate.

[0016] Preferably, in module M7, the σ calculation expression is: After calculating the deviation σ, the machining coordinate system in the programming model is corrected in angle, a new machining program is generated, the position accuracy of the machining features is maintained, and rapid clamping and positioning of the box bottom is achieved.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention combines actual production needs, processes positioning process holes, and uses tapered pins to connect the box bottom with the mirror milling equipment, so that the workpiece reference can easily coincide with the clamping tooling reference, the clamping correction time is short, the cost is low, and the production capacity and quality of parts are improved; (2) The present invention performs angle correction on the machining coordinate system in the NC programming body according to the numerical value of the offset, so that the XOY plane of the NC programming body is consistent with the actual machine tool, so that the machining datum of rough and fine machining remains consistent, the position accuracy of the machining features is guaranteed, and the rapid clamping and positioning of the box bottom is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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: Figure 1 The process flow of the integrally formed box bottom processing of the present invention; Figure 2 It is a schematic diagram of the engraved lines of the vertical lathe process of the integrally formed box bottom of the present invention; Figure 3 This is a schematic diagram of the mirror-image milling and clamping of the integrally formed box bottom of the present invention; Figure 4 This is a schematic diagram of the mirror-milling alignment of the integrally formed box bottom of the present invention; Figure 5 It is a schematic diagram of the rapid positioning of the mirror milling of the integrally formed box bottom of the present invention. DETAILED DESCRIPTION

[0019] 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.

[0020] Example 1 Figure 1 In the process flow of the integrally formed box bottom of the present invention, the box bottom will be clamped twice on the mirror milling equipment, and other processing steps will be performed during the two clamping processes. The box bottom part is a 3350-grade integrally formed box bottom, and the maximum diameter of the blank is 3700mm.

[0021] Step 1. When lathing the inner surface of the integrally formed box bottom, use a lettering knife to carve a circular line with a radius of 1820mm on the skirt edge of the box bottom. The lettering marks should follow the principle of clear visibility and easy operation. Use a conventional lettering knife to carve on the skirt edge of the box bottom to ensure that the lettering marks are clearly visible and can be felt by touching with the hand. The recommended lettering depth of the mark is 0.3mm, which can be quickly and conveniently obtained by the lettering knife without damaging the lettering knife.

[0022] Figure 2 It is a schematic diagram of the engraved lines of the vertical lathe process of integrally forming the bottom of the box according to the present invention.

[0023] Step 2: At two positions with a phase difference of 180°, use a carving knife to carve out quadrant lines with a length of 50mm and a depth of 0.3mm, which intersect with the circular line in step 1 to obtain two intersection points, such as Figure 2 As shown; Step 3: Drill through holes with diameters of 14 mm and 12 mm at the two intersections. Figure 2 As shown, it serves as the subsequent positioning reference; Step 4: On the upper end surface of the clamping fixture of the integrally formed box bottom mirror milling equipment, two through holes with a diameter of 12 mm are respectively processed at the coordinate points (0, +1820) and (0, -1820); Figure 3 It is a schematic diagram of the mirror-image milling and clamping of the integrally formed box bottom of the present invention.

[0024] Figure 4 It is a schematic diagram of the rapid positioning of the mirror milling of the integrally formed box bottom of the present invention.

[0025] Step 5: Place the bottom of the box on the fixture of the mirror milling equipment. Figure 3 As shown, the hole on the fixture is aligned with the hole on the bottom of the box. The 14mm hole on the bottom of the box can envelop the 12mm hole. Insert a 12mm diameter tapered locating pin to align the bottom of the box. Figure 4As shown in the figure, by compiling a CNC program for engraving the reference line, the machine tool spindle uses an engraving tool to engrave two centrally symmetrical reference lines with a depth of 1mm and a width of 0.5mm after rotating 10° clockwise along the center line of the 12mm through hole on the tooling, ensuring clear visibility and facilitating the spindle probe to accurately pick points on the reference line, reducing measurement deviation, as shown in the figure. Figure 5 As shown, mirror milling roughing is then started; Figure 5 It is a schematic diagram of the rapid positioning of the mirror milling of the integrally formed box bottom of the present invention.

[0026] Step 6, such as Figure 1 As shown in the figure, after the rough processing of the bottom mirror milling is completed, other processes will be carried out. When the bottom mirror milling is carried out again, the bottom of the box will be deformed. After the bottom of the box is re-aligned with the positioning pin, use the equipment spindle probe to select a point A at any position on a reference line, record the X-axis value X1=305.78 and the Y-axis coordinate value Y1=1836.35 of point A, and select a point B at any position on another reference line, record the X-axis value X2=-303.07 and the Y-axis coordinate value Y2=-1836.35 of point B, and use formula (1) to calculate the angle θ=9.41°.

[0027] Step 7: Formula (2) can be used to calculate the offset σ=0.59° of the actual position of the box bottom relative to the theoretical position. The process personnel make an angle correction to the machining coordinate system in the NC programming body according to the value of the offset σ. The machining coordinate system rotates 0.59° along the positive Z axis to make the XOY plane of the NC programming body consistent with the actual machine tool, so that the machining datum of rough and fine machining remains consistent, ensuring the position accuracy of the machining features and realizing rapid clamping and positioning of the box bottom.

[0028] Example 2 The present invention also provides a rapid positioning system for mirror milling of an integrally formed box bottom. The rapid positioning system for mirror milling of an integrally formed box bottom can be realized by executing the process steps of the rapid positioning method for mirror milling of an integrally formed box bottom. That is, a person skilled in the art can understand the rapid positioning method for mirror milling of an integrally formed box bottom as a preferred implementation of the rapid positioning system for mirror milling of an integrally formed box bottom.

[0029] The invention provides an integrally formed box bottom mirror milling rapid positioning system, comprising: Module M1: When the inner surface of the integrally formed box bottom is vertically turned, a circular ring line with a preset radius is carved on the skirt edge of the box bottom with a lettering knife; Module M2: Use a carving knife to carve quadrant lines at two positions with a phase difference of 180°, which intersect with the circular lines in module M1 to obtain two intersection points; Module M3: Drill through holes with different diameters at two intersections in module M2 for subsequent workpiece alignment; Module M4: Through holes of the same diameter are machined at two locations on the upper end surface of the clamping fixture of the integrally formed box bottom mirror milling equipment. The diameter value is the same as the minimum diameter value of the two through holes in module M3; Module M5: Align the holes on the fixture with the holes on the bottom of the box, insert the tapered locating pins, align the bottom of the box, and carve two central symmetric reference lines at any angle α between the center lines of the two through holes at the fixture position; Module M6: Use the spindle probe of the equipment to select a point on the reference line, record it as point A and point B, and calculate the angle θ between the line connecting point A and point B and the positive direction of the Y axis of the equipment;

[0030] Where X1 represents the coordinate value of the X axis of point A; X2 represents the coordinate value of the X axis of point B; Y1 represents the coordinate value of the Y axis of point A; Y2 represents the coordinate value of the Y axis of point B; Module M7: Set the angle between the center line of the two through holes at the tooling position and the positive direction of the Y axis of the equipment to β. When the bottom of the box is clamped later, the processing program is corrected by the angle deviation σ to achieve rapid clamping and positioning of the bottom of the box.

[0031] Preferably, in module M1, when the inner profile of the integrally formed box bottom is vertically turned, a circular line is engraved on the skirt edge of the box bottom with a lettering knife. The circular line is located in the plane area of ​​the skirt edge and close to the outer edge, and the engraved line depth is 0.3 mm; In module M2, at two positions with a phase difference of 180°, a quadrant line with a length of 50 mm and a depth of 0.3 mm was carved with a lettering knife, intersecting with the circular line in module M1 to obtain two intersection points; In module M3, through holes with diameters of d1 and d2 are drilled at two intersections, d1-d2=2mm, as a subsequent positioning reference.

[0032] In module M4, the diameter of the ring in module M1 is set to D, and through holes with a diameter equal to d2 are respectively machined at two positions with coordinate points (0, +D / 2) and (0, -D / 2) on the upper end surface of the clamping fixture of the integral forming box bottom mirror milling equipment; In module M5, align the holes on the fixture with the holes on the bottom of the box, insert conical locating pins with a diameter equal to d2 into the two through-hole positions, and the reference line position is the center line of the two through-holes at the fixture position rotated clockwise by a preset amplitude.

[0033] In module M6, when the probe is used to take points, the absolute values ​​of the X-axis or Y-axis directions of the two points are kept unchanged, that is, the absolute values ​​of the X-axis coordinates of point A and point B are always equal or the absolute values ​​of the Y-axis coordinates are always equal.

[0034] In module M7, the calculation expression of σ is: After calculating the deviation σ, the machining coordinate system in the programming model is corrected in angle, a new machining program is generated, the position accuracy of the machining features is maintained, and rapid clamping and positioning of the box bottom is achieved.

[0035] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0036] Those skilled in the art know that, in addition to implementing the system, device and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program 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, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0037] 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 method for rapid positioning of an integrally formed box bottom by mirror milling, characterized in that: include: Step 1: When lathing the inner surface of the integrally formed box bottom, use a carving knife to carve a circular ring line with a preset radius on the skirt edge of the box bottom; Step 2: Use a carving knife to carve quadrant lines at two positions with a phase difference of 180°, intersecting them with the circular lines in step 1 to obtain two intersection points; Step 3: Drill through holes with different diameters at the two intersections in step 2 for subsequent workpiece alignment; Step 4: Through holes of the same diameter are respectively machined at two locations on the upper end surface of the clamping fixture of the integrally formed box bottom mirror milling equipment, and the diameter value is the same as the minimum diameter value of the two through holes in step 3; Step 5: Align the holes on the fixture with the holes on the bottom of the box, insert the tapered locating pins, align the bottom of the box, and carve out two central symmetrical reference lines at any angle α between the center lines of the two through holes at the fixture position; Step 6: Use the device spindle probe to select a point on the reference line, record it as point A and point B, and calculate the angle θ between the line connecting point A and point B and the positive direction of the device Y axis; Where X1 represents the coordinate value of the X axis of point A; X2 represents the coordinate value of the X axis of point B; Y1 represents the coordinate value of the Y axis of point A; Y2 represents the coordinate value of the Y axis of point B; Step 7: Set the angle between the center line of the two through holes at the tooling position and the positive direction of the Y axis of the equipment to β. When the bottom of the box is clamped later, the processing program is corrected by the angle deviation σ to achieve rapid clamping and positioning of the bottom of the box.

2. The mirror milling rapid positioning method for the integrally formed box bottom according to claim 1 is characterized in that: In step 1, when the inner surface of the integrally formed box bottom is vertically turned, a circular ring line is engraved on the skirt edge of the box bottom with a lettering knife. The circular ring line is located in the plane area of ​​the skirt edge and close to the outer edge. The engraved line depth is 0.3mm; In step 2, at two positions with a phase difference of 180°, use a carving knife to carve quadrant lines with a length of 50 mm and a depth of 0.3 mm, which intersect with the circular line in step 1 to obtain two intersection points; In step 3, through holes with diameters of d1 and d2 are drilled at the two intersections, respectively, d1-d2=2mm, as a subsequent positioning reference.

3. The method for rapid positioning of the integrally formed box bottom by mirror milling according to claim 2 is characterized in that: In step 4, the diameter value of the ring in step 1 is set to D, and through holes with a diameter equal to d2 are respectively machined at two positions with coordinate points (0, +D / 2) and (0, -D / 2) on the upper end surface of the clamping fixture of the integral forming box bottom mirror milling equipment; In step 5, align the holes on the fixture with the holes on the bottom of the box, insert conical locating pins with a diameter equal to d2 into the two through-hole positions, and the reference line position is the center line of the two through-holes at the fixture position rotated clockwise by a preset amplitude.

4. The method for rapid positioning of the integrally formed box bottom by mirror milling according to claim 1 is characterized in that: In step 6, when using the probe to pick points, the absolute values ​​of the X-axis or Y-axis directions of the two points are kept unchanged, that is, the absolute values ​​of the X-axis coordinates of point A and point B are always equal or the absolute values ​​of the Y-axis coordinates are always equal.

5. The method for rapid positioning of the integrally formed box bottom by mirror milling according to claim 1 is characterized in that: In step 7, the expression for calculating σ is: After calculating the deviation σ, the machining coordinate system in the programming model is corrected in angle, a new machining program is generated, the position accuracy of the machining features is maintained, and rapid clamping and positioning of the box bottom is achieved.

6. An integrally formed box bottom mirror milling rapid positioning system, characterized in that: include: Module M1: When the inner surface of the integrally formed box bottom is vertically turned, a circular ring line with a preset radius is carved on the skirt edge of the box bottom with a lettering knife; Module M2: Use a carving knife to carve quadrant lines at two positions with a phase difference of 180°, which intersect with the circular lines in module M1 to obtain two intersection points; Module M3: Drill through holes with different diameters at two intersections in module M2 for subsequent workpiece alignment; Module M4: Through holes of the same diameter are machined at two locations on the upper end surface of the clamping fixture of the integrally formed box bottom mirror milling equipment. The diameter value is the same as the minimum diameter value of the two through holes in module M3; Module M5: Align the holes on the fixture with the holes on the bottom of the box, insert the tapered locating pins, align the bottom of the box, and carve two central symmetric reference lines at any angle α between the center lines of the two through holes at the fixture position; Module M6: Use the spindle probe of the equipment to select a point on the reference line, record it as point A and point B, and calculate the angle θ between the line connecting point A and point B and the positive direction of the Y axis of the equipment; Where X1 represents the coordinate value of the X axis of point A; X2 represents the coordinate value of the X axis of point B; Y1 represents the coordinate value of the Y axis of point A; Y2 represents the coordinate value of the Y axis of point B; Module M7: Set the angle between the center line of the two through holes at the tooling position and the positive direction of the Y axis of the equipment to β. When the bottom of the box is clamped later, the processing program is corrected by the angle deviation σ to achieve rapid clamping and positioning of the bottom of the box.

7. The mirror milling rapid positioning system for integrally formed box bottom according to claim 6 is characterized in that: In module M1, when the inner profile of the integrally formed box bottom is vertically turned, a circular ring line is engraved on the skirt edge of the box bottom with a lettering knife. The circular ring line is located in the plane area of ​​the skirt edge and close to the outer edge. The engraved line depth is 0.3mm. In module M2, at two positions with a phase difference of 180°, a quadrant line with a length of 50 mm and a depth of 0.3 mm was carved with a lettering knife, intersecting with the circular line in module M1 to obtain two intersection points; In module M3, through holes with diameters of d1 and d2 are drilled at two intersections, d1-d2=2mm, as a subsequent positioning reference.

8. The mirror image milling rapid positioning system for integrally formed box bottom according to claim 7 is characterized in that: In module M4, the diameter of the ring in module M1 is set to D, and through holes with a diameter equal to d2 are respectively machined at two positions with coordinate points (0, +D / 2) and (0, -D / 2) on the upper end surface of the clamping fixture of the integral forming box bottom mirror milling equipment; In module M5, align the holes on the fixture with the holes on the bottom of the box, insert conical locating pins with a diameter equal to d2 into the two through-hole positions, and the reference line position is the center line of the two through-holes at the fixture position rotated clockwise by a preset amplitude.

9. The mirror image milling rapid positioning system for integrally formed box bottom according to claim 6, characterized in that: In module M6, when the probe is used to take points, the absolute values ​​of the X-axis or Y-axis directions of the two points are kept unchanged, that is, the absolute values ​​of the X-axis coordinates of point A and point B are always equal or the absolute values ​​of the Y-axis coordinates are always equal.

10. The mirror image milling rapid positioning system for integrally formed box bottom according to claim 6, characterized in that: In module M7, the calculation expression of σ is: After calculating the deviation σ, the machining coordinate system in the programming model is corrected in angle, a new machining program is generated, the position accuracy of the machining features is maintained, and rapid clamping and positioning of the box bottom is achieved.

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