Efficient over-constrained parallel mechanism equipment for heavy-load milling

Abstract

The invention relates to mechanical manufacturing equipment. The invention aims to provide efficient over-constrained parallel mechanism equipment for heavy-load milling so as to solve the problems of high quality of machining equipment and insufficient precision of traditional machining equipment in an actual machining scene. According to the technical scheme, the invention discloses efficient over-constrained parallel mechanism equipment for heavy-load milling. The equipment is characterized by further comprising a door-frame-shaped support, a fixed platform, a movable platform and three branch chains, wherein the door-frame-shaped support is vertically fixed, a distance is kept between the door-frame-shaped support and the workpiece sliding table, the fixed platform can be vertically and movably positioned on the support, the movable platform is located between the workpiece sliding table and the support and provided with a spindle head, and the three branch chains are arranged between the fixed platform and the movable platform in parallel. In the three branch chains, the first branch chain and the second branch chain respectively comprise a rotating pair, a first moving pair and a hooke joint which are sequentially connected between the movable platform and the fixed platform, and the first moving pair is provided with a motor; the third branch chain comprises a ball pair, a second moving pair and a third moving pair which are sequentially connected between the movable platform and the fixed platform, wherein the second moving pair is provided with a motor.

Description

Technical Field

[0001] This invention relates to a mechanical manufacturing equipment, specifically a parallel mechanism equipment for heavy-duty milling. Background Technology

[0002] In high-end fields such as aerospace, defense, and automotive manufacturing, the demand for large, complex, and irregularly shaped structural components is increasing. These parts require high-precision machining through heavy-duty milling. Due to the hardness of the materials and the large size of the parts, stringent requirements are placed on the load capacity, rigidity, and machining accuracy of the machining equipment.

[0003] Traditional heavy-duty milling operations primarily rely on gantry CNC machine tools with a tandem structure. These machine tools achieve multi-axis motion through the tandem superposition of components such as the bed, column, slide, and spindle box. However, with the ever-increasing demands for machining efficiency, precision, and dynamic performance, the inherent drawbacks of the tandem structure are becoming increasingly apparent.

[0004] Compared to traditional serial mechanisms, parallel mechanisms have advantages such as greater rigidity, stronger flexibility, compact structure, large load-bearing capacity, high positioning accuracy, and superior attitude adjustment capability. They are conducive to more diversified processing and production at present, proving the practical value of parallel mechanisms in milling.

[0005] Therefore, how to provide a high-efficiency over-constraint parallel mechanism for heavy-duty milling is an urgent issue for industry professionals to address. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings in the above-mentioned background technology and provide a high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling, so as to solve the problems of high quality of machining equipment and insufficient precision of traditional machining equipment in actual machining scenarios.

[0007] The technical solution of this invention is: A high-efficiency over-constraint parallel mechanism for heavy-duty milling includes a horizontally movable workpiece slide with a clamp installed. The mechanism further includes a vertically fixed, portal-frame-shaped support maintained at a distance from the workpiece slide; a fixed platform vertically movable and positioned on the support; a moving platform located between the workpiece slide and the support and equipped with a spindle head; and three branches connected in parallel between the fixed platform and the moving platform. The first and second branches each include a revolute joint sequentially connected between the moving platform and the fixed platform, a first prismatic joint equipped with a motor, and a Hooke's joint. The third branch includes a ball joint sequentially connected between the moving platform and the fixed platform, a second prismatic joint equipped with a motor, and a third prismatic joint.

[0008] The fixed platform is vertically arranged and flat, with three openings arranged in a triangular pattern on its surface. The left and right sides of the fixed platform are respectively positioned on the support by vertically movable platforms. The first and second branches are respectively positioned in the two openings on the lower side by Hooke joints, and the third branch is positioned in the opening on the upper side by a third movable joint.

[0009] The three branches are all positioned in three openings of the fixed platform by a rectangular connector. The first connectors of the first and second branches are fixed in the two lower openings, while the second connector of the third branch is slidably positioned in the upper opening to form the third sliding pair. The upper opening is a vertically arranged rectangle, and the outer walls of the connectors are respectively provided with vertically arranged slides to slide with the two sides of the opening, thereby enabling vertical movement within the opening.

[0010] The first connector is a rectangular frame with a shaft hole on the top and bottom sides respectively. One rotating shaft of the Hooke hinge is arranged vertically and fixed on the first slider. The two ends of the rotating shaft are engaged with the two shaft holes on the rectangular frame. The other rotating shaft of the Hooke hinge is arranged horizontally and is divided into two coaxial sections. The two sections of the rotating shaft are respectively fixed on the left and right frame bars of the rectangular frame and extend outward to engage with the two shaft holes on the left and right side walls of the opening. The second connector is a vertically arranged rectangular frame, and the second slider in the second sliding pair is fixed in the second connector.

[0011] The third moving pair is driven by two linear drive components; each linear drive component includes a third ball screw that is vertically positioned on the opening wall by bearing seats at both ends, a second connector that engages with a nut on the third ball screw, and a third servo motor that is mounted on the top of the opening wall and coaxially connected to the third ball screw by a coupling.

[0012] The first sliding pair includes two first slide rails disposed on the first base and parallel to the length direction of the first base, and a first slider disposed on the first slide rails; a first ball screw is disposed between the two first slide rails and is provided with a first nut connecting the first slider, and a first servo motor drives the first ball screw.

[0013] The second sliding pair includes two second slide rails disposed on the second base and parallel to the length direction of the second base, and a second slider disposed on each of the second slide rails; a second ball screw is disposed between the two second slide rails and is provided with a second nut for connecting the second slider; a second servo motor is fixed to the second base and drives the second ball screw.

[0014] The first prismatic joints in the first and second branches move in directions parallel to the length of their respective branches; the second prismatic joints in the third branch move in directions parallel to the length of the third branch.

[0015] In the first and second branches, the axes of the two revolute joints are parallel and vertically arranged, and the two horizontal rotating shafts of the fixed platform connected by the two Hooke hinges are horizontally arranged and their axes coincide.

[0016] The mobile platform includes two mobile platform bases vertically fixed on the left and right sides of the opening, two mobile platform ball screws vertically and rotatably positioned on the two mobile platform bases and each having a nut seat, two mobile platform slide rails arranged parallel to each mobile platform ball screw and placed on both sides of the mobile platform ball screws, two mobile platform sliders disposed on each mobile platform slide rail and connected to the nut seat, and a mobile platform servo motor fixed on the mobile platform base and driving the ball screws.

[0017] The beneficial effects of this invention are as follows: This invention proposes a highly efficient over-constraint parallel mechanism for heavy-duty milling. Compared with traditional serial machining equipment, the moving platform has three degrees of freedom. Combined with the moving platform and workpiece slide, it can achieve five-axis linkage machining, realizing two rotational and three translational degrees of freedom, offering advantages such as good dynamic characteristics, high stiffness-to-weight ratio, and high machining accuracy. It can achieve better machining accuracy and higher machining efficiency for structural parts with relatively large mass, complex structure, and high machining accuracy requirements. Furthermore, the moving platform of this equipment can achieve relatively complex movements, avoiding defects such as milling damage to the surface of parts caused by interference between equipment. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural schematic diagram of Embodiment 1 of the present invention.

[0019] Figure 2 yes Figure 1 A schematic diagram of the front structure of the three central branches and the fixed platform.

[0020] Figure 3 yes Figure 1 A front structural diagram of the central support and the fixed platform.

[0021] Figure 4 yes Figure 1 A schematic diagram of the front structure of the China Mobile platform.

[0022] Figure 5 yes Figure 1 A side view of the China Mobile platform.

[0023] Figure 6 yes Figure 1 A three-dimensional structural diagram of the first branch in the middle.

[0024] Figure 7 yes Figure 1 A three-dimensional structural diagram of the third branch in the middle.

[0025] Figure 8 yes Figure 1 A schematic diagram of the front structure of the workpiece slide.

[0026] Figure 9 yes Figure 1 A top view of the working slide.

[0027] Figure 10 This is a three-dimensional structural schematic diagram of Embodiment 2 of the present invention.

[0028] Figure 11 yes Figure 10 A schematic diagram showing the connection relationship between the three branches and the fixed platform.

[0029] Figure 12 yes Figure 10 A schematic diagram showing the connection between the third branch and the fixed platform.

[0030] In the diagram, the labels are as follows: 1-Bracket; 2-Moving platform; 3-Fixed platform; 4-First branch; 5-Second branch; 6-Third branch; 7-Moving platform; 8-Spindle head; 9-Workpiece slide; 21-Moving platform base; 22-Moving platform slider; 23-Moving platform connector; 24-Nut seat; 25-Moving platform servo motor; 26-Fixed seat; 28-Moving platform slide rail; 29-Moving platform ball screw; 41-Revolute pair; 42-First base; 43-First ball screw; 44-First slide rail; 45-First slider; 46-First servo motor; 47-First connector; 48-First bearing seat. 60-Sphere; 61-Second base; 62-Second ball screw; 63-Second connector; 64-Second slider; 65-Second slide rail; 66-Second bearing seat; 67-Second servo motor; 68-Vertical slide rail; 69-Third servo motor; 610-Third ball screw; 91-Workpiece slide baffle; 92-Workpiece slide screw; 93-Workpiece slide rail; 94-Workpiece slide base; 96-Clamp; 98-Workpiece slide servo motor. Detailed Implementation

[0031] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0032] The orientation in the diagram is agreed upon as follows: Figure 3 For reference: the horizontal direction pointing left and right is the X-axis, the vertical direction is the Y-axis, and the front and back direction (perpendicular to the drawing surface) is the Z-axis.

[0033] Example 1 Figure 1 , Figure 2 The efficient over-constraint parallel mechanism equipment for heavy-duty milling, as shown, includes a support 1, a moving platform 2, a fixed platform 3, a first branch 4, a second branch 5, a third branch 6, a moving platform 7, a spindle head 8, and a workpiece slide 9. The workpiece slide 9 is vertically arranged and horizontally movable on the foundation. The portal frame-shaped support 1 is also vertically fixed on the foundation and maintains a distance from the workpiece slide; the plane of the portal frame is parallel to the moving axis of the workpiece slide 9. The moving platform 2 is installed on the left and right sides of the portal frame of the support and is vertically arranged. The fixed platform 3 is vertically arranged and vertically movable within the portal frame of the support via the moving platform. Three branches are arranged on the fixed platform, and one end of each branch extends from one side of the fixed platform (along...). Figure 3 The spindle head 8 extends outward from the plane of the moving platform 7 (i.e., in the Z-axis direction) and is connected to the moving platform; the spindle head 8 is fixed on the moving platform 7, and the axis of the spindle head 8 is perpendicular to the plane of the moving platform 7.

[0034] like Figure 2 As shown, the fixed platform 3 is flat and has three through-holes, arranged in a triangular pattern with two at the bottom and one at the top. The two lower branches are positioned within the two lower holes via Hooke's joints, while the upper branch is positioned within the upper hole via a third sliding joint. The ends of each branch extend outwards from the front and rear sides of the fixed platform. Specifically: the first branch 4 and the second branch 5 are inserted into the two lower holes, with one end extending forward and connecting to the moving platform via a rotating joint, and the other end extending backward and connecting to the fixed platform via a Hooke's joint; the third branch 6 is inserted into the upper hole, with one forward end connecting to the moving platform 7 via a ball joint, and the other rearward end connecting to the fixed platform via a third sliding joint.

[0035] Both the first and second branches include a revolute joint 41 connected sequentially between the moving platform and the fixed platform, a first prismatic joint equipped with a motor, and a Hooke hinge; in the first branch 4 and the second branch 5, the axes of the two revolute joints are parallel to each other and arranged vertically, and the two Hooke hinges connecting the two rotating shafts of the fixed platform 3 are arranged horizontally and their axes coincide.

[0036] The third branch 6 consists of a ball joint, a second sliding joint equipped with a motor, and a third sliding joint connected sequentially between the moving platform and the fixed platform.

[0037] like Figure 3 , Figure 4 and Figure 5As shown, the mobile platform 2 is mounted vertically on the bracket 1. The mobile platform 2 includes two platform sliding pairs fixed inside the bracket on the left and right sides and capable of moving along the Y-axis. Each platform sliding pair includes a mobile platform base 21, a mobile platform slider 22, a mobile platform connector 23, a nut seat 24, a mobile platform servo motor 25, a fixed seat 26, a mobile platform coupling 27, two mobile platform slide rails 28, and a mobile platform ball screw 29. Two mobile platform bases 21 are vertically fixed inside the left and right side frames of the bracket. Two mobile platform slide rails 28 are vertically fixed on each mobile platform base. The two ends of the mobile platform ball screw are rotatably and vertically positioned on the mobile platform base 21 via support seats and located between the two slide rails. Each slide rail is equipped with two mobile platform sliders 22, which are connected to a mobile platform connector 23. The two connectors are vertically fixed on the left and right sides of the fixed platform. The mobile platform servo motor 25 is fixed to the mobile platform base 21, and a nut seat 24 that mates with the mobile platform ball screw 29 is connected to the mobile platform connector 23. The output shaft of the mobile platform servo motor 25 is coaxially connected to the mobile platform ball screw 29 via a mobile platform coupling 27, thereby driving the mobile platform ball screw 29 to rotate. This, in turn, drives the fixed platform 3 to translate along the mobile platform slide rails 28 via the mobile platform connector 23, enabling the fixed platform to move along the Y-axis.

[0038] like Figure 6As shown, the first branch 4 and the second branch 5 have the same structure, both consisting of a revolute joint, a first prismatic joint equipped with a motor, and a Hooke's joint connected sequentially between the moving platform and the fixed platform. The axes of the revolute joints of both branches are arranged vertically. The first prismatic joint includes a first slide rail 44 and a first slider 45. The two first slide rails 44 are set on the first base and are parallel to the length direction of the first base. The first ball screw 43, supported by the first bearing seats 48 at both ends, is set in the middle of the two first slide rails and is parallel to the two first slide rails. Each first slide rail is equipped with a first slider 45. The first servo motor 410 is fixed on the first base 42. The output shaft of the first servo motor is coaxially connected to the first ball screw through a coupling. The first nut that cooperates with the first ball screw 43 is connected to the slider 45, and the first slider is then connected to the Hooke's joint. The first connector 47 is positioned in the two openings below the fixed platform. The connector is a rectangular frame formed by four frame bars. A shaft hole is opened on the top and bottom frame bars respectively. One rotating shaft of the Hooke hinge is arranged vertically and fixed on the first slider. The two ends of the rotating shaft are respectively engaged with the two shaft holes. The other rotating shaft of the Hooke hinge is arranged horizontally and divided into two coaxial sections. The two sections of the rotating shaft are respectively fixed on the left and right frame bars of the rectangular frame and extend outward to engage with the two shaft holes on the left and right side walls of the opening, thereby positioning the first branch or the second branch in the opening of the fixed platform.

[0039] In the first branch 4 and the second branch 5, one end of the first base is connected to the moving platform 7 via a revolute joint, and the other end is respectively equipped with a first servo motor 410; both the first branch 4 and the second branch 5 are connected to the fixed platform via their respective Hooke joints. When the first servo motor is started, it can drive the first ball screw 43 to rotate, thereby driving the first base 42 to move along the first slider, so that the first branch 4 or the second branch 5 moves relative to the fixed platform.

[0040] The third branch 6 consists of a ball joint (including a ball 60 and a ball shell that mates with the ball), a second sliding joint equipped with a motor, and a third sliding joint, which are sequentially connected between the moving platform and the fixed platform.

[0041] The second sliding pair includes a second slider 64 and a second slide rail 65; one end of the second base is connected to the moving platform 7 via a ball joint, and the other end is equipped with a second servo motor 67; two second slide rails 65 are arranged on the second base 61 and parallel to the length direction of the second base; a second ball screw 62, supported by second bearing seats 66 at both ends, is arranged in the middle of the two second slide rails and parallel to the two second slide rails; a second slider 64 is arranged on each second slide rail; the second servo motor 67 is fixed on the second base, and the output shaft of the second servo motor is coaxially connected to the second ball screw 62 via a coupling; a second nut fitted on the second ball screw is connected to the second slider 64; the second slider driven by the second ball screw is then fixed in the second connecting member. When the second servo motor is started, it can drive the second ball screw 62 to rotate, thereby driving the second base 61 to move along the second slider, so that the third branch moves perpendicular to the plane of the fixed platform.

[0042] The opening above the fixed platform is a vertically arranged rectangle. A second connector 63 is slidably installed in the opening. The connector is a rectangular frame with vertically arranged slide rails on both outer walls. The two slide rails slide and engage with the two edges of the opening to form a third sliding pair. This allows the third branch to move vertically in the opening above through the third sliding pair. Obviously, the third sliding pair can only move passively because it is not equipped with a power source.

[0043] When the servo motors in the three branches are running, they can simultaneously drive the base to move (forward or backward), enabling the moving platform 7 and the spindle head 8 to move horizontally along the Z-axis. When the second servo motor 67 in the third branch 6 is not running, the first servo motors in the first branch 4 and the second branch 5 are running simultaneously, which can drive the first base to move forward or backward, enabling the moving platform 7 and the spindle head 8 to rotate along the Y-axis. When the first servo motors in the first branch 4 and the second branch 5 are not running simultaneously, and the second servo motor in the third branch 6 is running, it can drive the second base in the third branch to move, enabling the spindle head 8 to rotate along the X-axis.

[0044] like Figure 8 , Figure 9As shown, the workpiece slide 9 (existing technology) has a sliding pair at its bottom end that moves along the length of the workpiece slide. The sliding pair includes a workpiece slide 92, two workpiece slide rails 93, a workpiece slide base 94, and a workpiece slide servo motor 98. The two workpiece slide rails 93 are arranged parallel to each other and fixed to the workpiece slide base 94, and are horizontally positioned in front of the fixed platform 3. A lead screw 92 is mounted on the workpiece slide base at the middle position of the two workpiece slide rails via a bearing seat and is parallel to the two workpiece slide rails. The nut on the lead screw is connected to the sliders on the two workpiece slide rails. The servo motor 98 is also mounted on the workpiece slide base and is coaxially connected to the lead screw 92 via a coupling. The two workpiece slides 9 are vertically arranged and equipped with clamps. The bottom ends of the workpiece slides are fixed to the sliders of the two workpiece slide rails 93, thus enabling movement along the X-axis direction (parallel to the X-axis). Figure 3 (The image shows horizontal movement); two workpiece slides are respectively equipped with a clamp 96 on one side facing each other, for jointly clamping the workpiece to be processed. The workpiece slide servo motor 98 drives the workpiece slide lead screw 92 to rotate, which in turn drives the clamp 96 to translate along the workpiece slide rail 93, so that the workpiece slide moves in the X-axis direction; thereby adjusting the processing position of the workpiece to be processed.

[0045] Example 2 The structure of this embodiment is basically the same as that of embodiment 1, the only difference being that the second connecting member 63 of the third branch 6 is an active moving component; Figure 10 , Figure 11 , Figure 12 As shown, two linear drive components are installed in the opening positioned by the third branch. The two linear drive components are vertically installed on the left and right side walls of the opening, respectively. In each linear drive component, the two ends of the third ball screw 610 are vertically positioned on the vertical slide rail 68 through the bearing seat. The third nut is fixedly connected to the connecting part that serves as the slider. The third servo motor 69 is installed at the top of the vertical slide rail and is coaxially connected to the screw through the coupling.

[0046] Clearly, with the addition of a linear drive component, the third prismatic joint can move up and down actively, increasing the range of motion of the third branch.

[0047] The first branch 4, the second branch 5, and the third branch 6 of this invention contain moving pairs that move along the branch direction, which are active pairs. In addition, the workpiece slide 9 can translate along the X direction, and the fixed platform 3 can translate along the Y direction through the moving platform 2. Therefore, there are two rotational and three translational degrees of freedom between the fixed platform 3, the moving platform 8, and the workpiece slide 9, which enables five-axis linkage machining of the parts.

[0048] This invention is not limited to the specific embodiments described above. Anyone inspired by this invention can derive other forms of efficient over-constraint parallel mechanism equipment for heavy-duty milling and their usage methods. All equivalent variations and modifications made within the scope of the claims of this invention should be considered within the scope of this invention.

Claims

1. A high-efficiency over-constraint parallel mechanism for heavy-duty milling, comprising a horizontally movable workpiece slide (9) equipped with a fixture (96), characterized in that: The equipment also includes a door frame-shaped support (1) that is vertically fixed and keeps a distance from the workpiece slide, a fixed platform (3) that is vertically movable and positioned on the support, a moving platform (7) located between the workpiece slide and the support and equipped with a spindle head (8), and three branches arranged in parallel between the fixed platform and the moving platform; of the three branches, the first branch (4) and the second branch (5) each include a rotating joint (41) connected in sequence between the moving platform and the fixed platform, a first locating joint equipped with a motor and a Hooke joint; the third branch (6) includes a ball joint connected in sequence between the moving platform and the fixed platform, a second locating joint equipped with a motor and a third locating joint.

2. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 1, characterized in that: The fixed platform (3) is vertically arranged and flat, with three openings arranged in a triangular pattern on its surface. The left and right sides of the fixed platform are respectively positioned on the support by a vertically movable platform (2). The first branch (4) and the second branch (5) are respectively positioned in the two openings on the lower side by a Hooke joint, and the third branch (6) is positioned in the opening on the upper side by a third movable joint.

3. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 2, characterized in that: The three branches are all positioned in the three openings of the fixed platform by a rectangular connector. The first connector (47) provided in the first branch and the second branch is fixed in the two openings on the lower side, and the second connector (63) provided in the third branch is slidably positioned in the opening on the upper side to form the third moving pair. The opening on the upper side is a vertically arranged rectangle. The outer walls on both sides of the connector are respectively made with vertically arranged slides to slide with the two sides of the opening, so that it can move vertically in the opening.

4. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 3, characterized in that: The first connector (47) is a rectangular frame with a shaft hole on the top and bottom sides respectively. One rotating shaft of the Hooke hinge is arranged vertically and fixed on the first slider. The two ends of the rotating shaft are respectively engaged with the two shaft holes on the rectangular frame. The other rotating shaft of the Hooke hinge is arranged horizontally and divided into two coaxial sections. The two rotating shaft sections are respectively fixed on the left and right frame bars of the rectangular frame and extend outward to engage with the two shaft holes on the left and right side walls of the opening. The second connector (63) is a vertically arranged rectangular frame, and the second slider in the second sliding pair is fixed in the second connector.

5. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 4, characterized in that: The third moving pair is driven by two linear drive components; each linear drive component includes a third ball screw (610) vertically positioned on the opening wall by bearing seats at both ends, a second connector (63) cooperating with a nut on the third ball screw, and a third servo motor (69) mounted on the top of the opening wall and coaxially connected to the third ball screw by a coupling.

6. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 5, characterized in that: The first sliding pair includes two first slide rails (44) disposed on the first base and parallel to the length direction of the first parallel base, and a first slider (45) disposed on the first slide rails; a first ball screw (43) is disposed between the two first slide rails and is provided with a first nut for connecting the first slider; a first servo motor (410) is fixed to the first base and drives the first ball screw.

7. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 6, characterized in that: The second sliding pair includes two second slide rails (65) disposed on the second base 61 and parallel to the length direction of the second base, and a second slider (64) disposed on each second slide rail; a second ball screw (62) is disposed between the two second slide rails and is equipped with a second nut connecting the second slider (64); a second servo motor (67) is fixed to the second base and drives the second ball screw.

8. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 7, characterized in that: The first moving joints in the first and second branches move in directions parallel to the length direction of their respective branches; the axis of the second moving joint in the third branch is parallel to the length direction of the third branch.

9. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 8, characterized in that: In the first branch (4) and the second branch (5), the axes of the two revolute joints are parallel to each other and vertical. The two horizontal rotating shafts of the fixed platform (3) are arranged in a straight line and connected by two Hooke hinges, with their axes coinciding.

10. The high-efficiency over-constraint parallel mechanism equipment for heavy-duty milling according to claim 9, characterized in that: The mobile platform includes two mobile platform bases (21) vertically fixed on the left and right sides of the opening, two mobile platform ball screws (29) vertically and rotatably positioned on the two mobile platform bases and equipped with nut seats, two mobile platform slide rails (28) arranged parallel to each mobile platform ball screw and placed on both sides of the mobile platform ball screw, two mobile platform sliders (22) disposed on each mobile platform slide rail and connected to the nut seats, and a mobile platform servo motor (25) fixed on the mobile platform base and driving the ball screws.

Images