A topology-optimized CNC boring and milling machine right-angle milling head housing and method

Abstract

This invention belongs to the field of CNC machine tool technology, specifically providing a topology-optimized right-angle milling head housing for a CNC boring and milling machine and a method thereof. The housing includes a ram connecting part, a right-angle rotating milling head connecting part, and a transition part connecting the ram connecting part and the right-angle rotating milling head connecting part. The ram connecting part includes a tapered cylinder with end plates at both ends. A plurality of connecting posts are provided between the two sets of end plates, and threaded holes are provided through the connecting posts. The optimized milling head housing exhibits reduced weight and significantly improved static and dynamic characteristics.

Description

Technical Field

[0001] This invention belongs to the field of CNC machine tool technology, and specifically relates to a topology-optimized CNC boring and milling machine right-angle milling head housing and method. Background Technology

[0002] Heavy-duty CNC boring and milling machines or gantry milling machines are typically equipped with right-angle milling heads and universal milling heads to expand their machining capabilities and achieve five-sided machining. The milling head housing is the basic load-bearing component of the right-angle milling head. Its large end is connected to the machine tool's square slide ram, while the rotating housing portion of the right-angle milling head is fixed to its small end. Other components such as the indexing rotation device, spindle zero-positioning device, cooling device, and lubrication device are all mounted on the milling head housing. The cutting forces generated during machining are ultimately transmitted to and borne by the milling head housing; therefore, the static and dynamic characteristics of the milling head housing directly determine the machining performance of the milling head.

[0003] Milling head housings are usually composed of simple geometric shapes. They are simple in appearance, easy to process, and easy to manufacture. However, they are bulky and heavy, lack dynamic characteristics, and are prone to vibration during high-speed machining, which cannot meet the requirements for improving machining efficiency and quality. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a topology-optimized CNC boring and milling machine right-angle milling head housing and method, which reduces the weight of the housing and significantly improves its static and dynamic characteristics.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a topology-optimized CNC boring and milling machine right-angle milling head housing, including a ram connecting part and a milling head right-angle rotating body connecting part, and a transition part connecting the ram connecting part and the milling head right-angle rotating body connecting part. The ram connecting part includes a tapered cylinder, with end plates at both ends of the tapered cylinder, and a plurality of connecting posts between the two sets of end plates, with threaded holes through the connecting posts.

[0006] In a preferred embodiment, one side of the connecting column is connected to the outer wall of the cone, and the cross-section of the connecting column is a "U" shaped structure.

[0007] In a preferred embodiment, several reinforcing ribs are provided between the two sets of end plates.

[0008] In a preferred embodiment, the reinforcing ribs include end reinforcing ribs and intermediate reinforcing ribs. The end reinforcing ribs are located at the corners of the end plates, and the intermediate reinforcing ribs are located between the two sets of end reinforcing ribs.

[0009] In a preferred embodiment, the connecting post is located at the end reinforcing rib and is connected to the end reinforcing rib.

[0010] In a preferred embodiment, the rectangular opening formed by the end reinforcing rib and the end plate is closed by a cover plate. The end reinforcing rib and the end plate are provided with mounting grooves. The cover plate is placed in the mounting grooves and fixed to one side of the end plate by screws. There is a cavity between the cover plate and the cone.

[0011] In a preferred embodiment, the transition section is a conical structure, with one end closer to the ram connection being larger than the other end. The cross-section of the transition section is an irregular curved surface formed by two ellipses intersecting in a cross shape, and the interior of the transition section is an inner conical cylinder that communicates with the conical cylinder.

[0012] In a preferred embodiment, the taper of the transition section is 6°.

[0013] In a preferred embodiment, the right-angle rotating part of the milling head includes a connecting ring connected to the transition part, and the end of the connecting ring is provided with an annular T-groove.

[0014] This invention also provides a topology optimization method for the housing of a right-angle milling head on a CNC boring and milling machine, comprising the following steps:

[0015] Step 1: Optimize the finite element analysis of the front milling head housing, including the following steps:

[0016] S101. Set the load according to actual needs;

[0017] S102. Set the basic material parameters, including elastic modulus, Poisson's ratio, and density;

[0018] S103. Model preprocessing: Remove screw holes, fillets, and chamfers that do not affect the analysis, then perform mesh generation, apply loads in the simulation environment of the finite element analysis software, and solve to obtain deformation cloud map;

[0019] Step 2, Topology Optimization: Set the position of the milling head shell that cannot be changed as a restricted area and freeze it. Set the design response for volume, strain energy and absolute value respectively. Set the minimum value of stress or strain as the optimization target and perform optimization solution to obtain the topology-optimized variable density cloud map and obtain the area to be removed.

[0020] Step 3: Shape Optimization: Set the cross-sectional shape of the transition section to an irregular curved surface formed by the intersection of two ellipses. Optimize the dimensions of the major and minor axes of the ellipses and the taper of the transition section. Set the goal of maximizing the first-order frequency without increasing the mass, and solve to obtain the final shape and size.

[0021] This invention provides a topology-optimized right-angle milling head housing for CNC boring and milling machines, along with a method thereof. The milling head housing, after topology and shape optimization, is lighter and possesses superior static and dynamic characteristics. In practice, it can increase tool speed, increase feed rate, improve machining efficiency, and enhance machining quality. The milling head housing has a simple shape, good manufacturability, and the saved space can be used to install various pipelines. It can be widely applied to right-angle milling heads for CNC boring and milling machines and gantry milling attachments. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0023] Figure 1 This is a schematic diagram of the existing milling head housing;

[0024] Figure 2 This is a cross-sectional view of an existing shampoo box.

[0025] Figure 3 This is a schematic diagram of the overall structure of the present invention;

[0026] Figure 4 This is a schematic diagram of the overall structure of the right-angle milling head housing after the cover plate of the present invention is installed;

[0027] Figure 5 This is a front view of the right-angle milling head housing of the present invention;

[0028] Figure 6 This is a side view of the right-angle milling head housing of the present invention;

[0029] Figure 7 for Figure 5 A cross-sectional view along plane AA;

[0030] Figure 8 for Figure 5 A cross-sectional view along plane BB;

[0031] Figure 9 for Figure 7 A sectional view along the CC plane;

[0032] Figure 10 for Figure 9 A cross-sectional view along plane DD;

[0033] Figure 11 Optimize the deformation cloud map of the front milling head housing;

[0034] Figure 12 Stress-deformation contour plot of VON mises before optimization;

[0035] Figure 13 To optimize the first-order mode shape of the front milling head housing;

[0036] Figure 14To optimize the second-order mode shape of the front milling head housing;

[0037] Figure 15 To optimize the third-order vibration mode diagram of the front milling head housing;

[0038] Figure 16 Variable density cloud map of the milling head housing after topology optimization;

[0039] Figure 17 To optimize the deformation cloud map of the milling head housing;

[0040] Figure 18 VON mises stress contour plot of the optimized milling head housing

[0041] Figure 19 The optimized first-order vibration mode diagram of the milling head housing;

[0042] Figure 20 The optimized second-order vibration mode diagram of the milling head housing;

[0043] Figure 21 The optimized third-order vibration mode diagram of the milling head housing

[0044] In the figure: ram connecting part 100, cone cylinder 110, end plate 120, connecting column 130, screw hole 131, reinforcing rib 140, end reinforcing rib 141, intermediate reinforcing rib 142, cover plate 150, mounting groove 160;

[0045] Milling head right-angle rotating connecting part 200, connecting ring 210, annular T-slot 220;

[0046] Transition section 300, irregular curved surface 310, inner cone 320. Detailed Implementation

[0047] Example 1:

[0048] See the milling head housing before optimization. Figures 1-2 As shown, its shape is divided into three parts. The square body is connected to the square slide of the CNC boring and milling machine, and there are bolt holes at the four corners for fastening. The head, which is connected to the right-angle rotating part of the milling head, is round, with an annular T-slot, and a conical transition part in the middle.

[0049] like Figures 3-10 As shown, a topology-optimized right-angle milling head housing for a CNC boring and milling machine includes a ram connecting portion 100, a right-angle rotating milling head connecting portion 200, and a transition portion 300 connecting the ram connecting portion 100 and the right-angle rotating milling head connecting portion 200, as shown. Figure 1 and 10As shown, the ram connection part 100 includes a cone cylinder 110, and end plates 120 are provided at both ends of the cone cylinder 110. The end plates 120 are rectangular structures. In this embodiment, the thickness of the end plates 120 is 20mm. Several connecting posts 130 are provided between the two sets of end plates 120, and screw holes 131 are provided through the connecting posts 130.

[0050] After topology optimization, the original square section is transformed into a structure with a tapered cylinder 110 and an end plate 120. By setting the end plate 120, the contact area with the CNC boring ram is ensured while the weight of the milling head housing is reduced.

[0051] like Figure 9 As shown, one side of the connecting column 130 is connected to the outer wall of the cone 110. The cross-section of the connecting column 130 is a "U" shaped structure, that is, the connecting column 130 is located at the four corners of the end plate 120 and is set as an integral structure with the cone 110.

[0052] To ensure the overall strength of the shell, several reinforcing ribs 140 are provided between the two sets of end plates 120, such as... Figure 9 As shown, the reinforcing rib 140 includes end reinforcing ribs 141 and intermediate reinforcing ribs 142. The end reinforcing ribs 141 are located at the corner of the end plate 120, and the intermediate reinforcing ribs 142 are located between the two sets of end reinforcing ribs 141. The number of reinforcing ribs 140 is 8, and the thickness of the reinforcing ribs 140 is 20mm.

[0053] The connecting post 130 is located at the end reinforcing rib 141 and is connected to the end reinforcing rib 141. The rectangular opening formed by the end reinforcing rib 141 and the end of the end plate 120 is closed by the cover plate 150. The end of the end reinforcing rib 141 and the end plate 120 are provided with mounting grooves 160. The cover plate 150 is disposed in the mounting grooves 160 and is fixed to one side of the end plate 120 by screws. There is a cavity between the cover plate 150 and the cone 110.

[0054] The cavity between the cover plate 150 and the cone 110 can be used to arrange various pipelines and install accessories.

[0055] Preferably, the transition portion 300 has a tapered structure, with one end near the ram connection portion 100 being larger than the other end, such as... Figure 6 and 8 As shown, the cross-section of the transition section 300 is an irregular curved surface 310 formed by two ellipses intersecting in a cross shape, and the interior of the transition section 300 is an inner cone 320 that communicates with the cone 110.

[0056] In this embodiment, the taper of the transition portion 300 is 6°.

[0057] The milling head right-angle rotating connecting part 200 includes a connecting ring 210 connected to the transition part 300, and the end of the connecting ring 210 is provided with an annular T-groove 220.

[0058] Example 2:

[0059] A topology optimization method for the housing of a right-angle milling head on a CNC boring and milling machine includes the following steps:

[0060] Step 1: Optimize the finite element analysis of the front milling head housing, including the following steps:

[0061] S101. Set the load according to actual needs.

[0062] In this embodiment, the feed force is 2454 N; the main cutting force is 7362 N; the radial force is 4070 N; the bending moment is 1160 Nm; and the torque is 1627 Nm.

[0063] S102. Set the basic parameters of the material, including elastic modulus, Poisson's ratio, and density.

[0064] In this embodiment, HT300 material was selected, with an elastic modulus of 143 GPa, a Poisson's ratio of 0.27, and a density of 7300 kg / m³. 3 .

[0065] S103. Model preprocessing: Remove screw holes, fillets, and chamfers that do not affect the analysis, then use CTETRA4 elements to generate the mesh, and perform mesh element quality checks.

[0066] Entering the simulation environment, the ram connection 100 is fixed. After applying the load in the NX Nastran software simulation environment, the deformation cloud map is obtained.

[0067] Figure 11 To optimize the deformation contour plot of the front milling head housing, Figure 12 The image shows the stress-deformation contour plot of VON mises before optimization. Figure 11 The maximum element node deformation is shown to be 9.6 μm, from Figure 12 The von Mises stress of the largest element node is 4.5 MPa, which is far below the allowable stress of HT300 material, indicating that there is considerable room for optimization of the milling head shell.

[0068] Modal analysis of the shell before optimization: Figure 13-15 To optimize the first three vibration modes of the front milling head housing, deformation mainly occurs in the middle and head of the housing. The first vibration mode is horizontal oscillation, the second vibration mode is vertical oscillation, and the third vibration mode is torsional vibration.

[0069] Step 2, Topology Optimization: The unchangeable position of the milling head housing is set as a restricted region and frozen. Design responses are set for volume, strain energy, and absolute value, with stress or strain as the minimum value as the optimization objective. Volume constraint ≤ 0.4 (relative), displacement constraint ≤ 0.02 mm. The optimization solution yields a topology-optimized variable density contour map, as shown below. Figure 16 As shown, the regions that need to be removed are obtained; the red "1" regions are the regions to be retained, and the blue "0" regions are the regions to be removed.

[0070] Further cross-sectional analysis of the STL model generated by topology optimization yielded the cross-section and dimensions of the cone 110 shown in Example 1.

[0071] Step 3, Shape Optimization: Since an ellipse has a higher moment of inertia than a circle, and its bending stiffness is higher along its major axis, and considering that the first and second vibration modes occur in both the horizontal and vertical directions, the major axes of the two ellipses are arranged in a cross shape to correspond to them.

[0072] The cross-sectional shape of the transition section 300 is set as an irregular curved surface 310 formed by the intersection of two ellipses. The dimensions of the major and minor axes of the ellipse and the taper of the transition section 300 are optimized. The goal is to maximize the first-order frequency without increasing the mass. The solution is then performed, taking into account the casting process, to obtain the final shape and size.

[0073] To verify the performance of the milling head housing provided by this invention, a finite element analysis was performed on the optimized milling head housing:

[0074] 1) Static analysis. The specific settings are the same as in step one. See the results below. Figures 17-18 .

[0075] 2) Modal analysis. The optimized first three mode shapes are shown below. Figures 19-21 .

[0076] 3) Comparison of static and dynamic characteristics of the milling head housing before and after optimization, see Table 1.

[0077]

[0078] After optimization, the mass of the milling head housing decreased by 6.8%, the deformation under extreme working conditions decreased by 42.2%, the VON MISES stress decreased by 50.2%, and the static characteristics were significantly improved. The first three mode shapes were the same, the frequencies all increased by more than 15%, and the frequency vibration displacements all decreased by more than 11%, resulting in a significant improvement in dynamic characteristics.

[0079] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The embodiments and features described in this application can be arbitrarily combined with each other without conflict. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A topology optimization method for the housing of a right-angle milling head on a CNC boring and milling machine, characterized in that, The topology-optimized CNC boring and milling machine right-angle milling head housing is used to design a CNC boring and milling machine right-angle milling head housing. The topology-optimized CNC boring and milling machine right-angle milling head housing includes a ram connecting part (100) and a milling head right-angle rotating body connecting part (200) and a transition part (300) connecting the ram connecting part (100) and the milling head right-angle rotating body connecting part (200). The ram connecting part (100) includes a cone (110). The cone (110) has end plates (120) at both ends. A plurality of connecting posts (130) are provided between the two sets of end plates (120). The connecting posts (130) are provided with through screw holes (131). The method includes the following steps: Step 1: Optimize the finite element analysis of the front milling head housing, including the following steps: S101. Set the load according to actual needs; S102. Set the basic material parameters, including elastic modulus, Poisson's ratio, and density; S103. Model preprocessing: Remove screw holes, fillets, and chamfers that do not affect the analysis, then perform mesh generation, apply loads in the simulation environment of the finite element analysis software, and solve to obtain deformation cloud map; Step 2, Topology Optimization: Set the position of the milling head shell that cannot be changed as a restricted area and freeze it. Set the design response for volume, strain energy and absolute value respectively. Set the minimum value of stress or strain as the optimization target and perform optimization solution to obtain the topology-optimized variable density cloud map and obtain the area to be removed. Step 3, Shape Optimization: Set the cross-sectional shape of the transition part (300) to an irregular curved surface (310) formed by the intersection of two ellipses. Optimize the dimensions of the major and minor axes of the ellipse and the taper of the transition part (300). Set the goal to maximize the first-order frequency without increasing the mass, and solve to obtain the final shape and size.

2. The topology optimization method for the right-angle milling head housing of a CNC boring and milling machine according to claim 1, characterized in that, The connecting column (130) is connected to the outer wall of the cone (110) on one side, and the cross-section of the connecting column (130) is a "U" shaped structure.

3. The topology optimization method for the right-angle milling head housing of a CNC boring and milling machine according to claim 1, characterized in that, Several reinforcing ribs (140) are provided between the two sets of end plates (120).

4. The topology optimization method for the right-angle milling head housing of a CNC boring and milling machine according to claim 3, characterized in that, The reinforcing ribs (140) are provided in eight parts, including end reinforcing ribs (141) and intermediate reinforcing ribs (142). The end reinforcing ribs (141) are provided at the corner of the end plate (120), and the intermediate reinforcing ribs (142) are provided between the two sets of end reinforcing ribs (141).

5. The topology optimization method for the right-angle milling head housing of a CNC boring and milling machine according to claim 4, characterized in that, The connecting column (130) is located at the end reinforcing rib (141) and is connected to the end reinforcing rib (141).

6. The topology optimization method for the right-angle milling head housing of a CNC boring and milling machine according to claim 4, characterized in that, The rectangular opening formed by the end reinforcing rib (141) and the end plate (120) is closed by the cover plate (150). The end reinforcing rib (141) and the end plate (120) are provided with mounting grooves (160). The cover plate (150) is set in the mounting groove (160) and fixed to one side of the end plate (120) by screws. There is a cavity between the cover plate (150) and the cone (110).

7. The topology optimization method for the right-angle milling head housing of a CNC boring and milling machine according to claim 1, characterized in that, The transition section (300) is a conical structure, with one end near the ram connection section (100) being larger than the other end. The cross-section of the transition section (300) is an irregular curved surface (310) formed by two ellipses intersecting in a cross shape. The interior of the transition section (300) is an inner conical cylinder (320) that communicates with the conical cylinder (110).

8. The topology optimization method for the right-angle milling head housing of a CNC boring and milling machine according to claim 1, characterized in that, The transition section (300) has a taper of 6°.

9. The topology optimization method for the right-angle milling head housing of a CNC boring and milling machine according to claim 1, characterized in that, The milling head right-angle rotating connection part (200) includes a connecting ring (210) connected to the transition part (300), and the end of the connecting ring (210) is provided with an annular T-slot (220).

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