The 15945 machine tool vertical milling key machining center is a new product independently developed and designed by a machine tool factory based on technology imported from abroad. The column is an important part of the machine tool. It not only moves in the horizontal direction, but also supports the various components connected to the machine tool, and is subjected to various loads such as cutting forces. Therefore, the rigidity of the column has a great influence on the machining accuracy of the machine tool. The column is a thin-walled structure with open holes on the hollow surface. Under the action of external forces such as cutting force, the designer believes that it is possible to make the two walls of the column wide and widely deformed. Therefore, a plurality of reinforcing ribs are added to the inner and outer walls of the original designed column to ensure the rigidity of the column. However, 圮6 requires reinforcement. It is unclear how much the column is deformed by the external load as a result of no experimental research and analytical calculations. The work of this paper is the static stiffness of the 15945 machine column and the finite element analysis. The analysis is done with structural analysis software, version 97 on the 586 microcomputer.
1Structural structure and force of the column 945 machine column structure 1. The length and width of the column are 2, the thickness of the rib is the sweat hole on the side wall of the 20 column, the village material is 300. The column is placed on the bottom of the rolling wire The slider of the bar moves back and forth in the horizontal direction of the paper under the action of the other roller screw, thereby realizing different parts of the processed part. The column is connected to the base with 16 bolts.
In addition to its own weight, the column is also subjected to other loads. The load in the vertical direction comes from the pressure of other parts acting on the column with a weight of 14 70N, 3; part of the machine when the slider is out of the M distal end, the machine tool seems to have a large cutting force acting on the front and rear sidewalls through the sliding seat. Farm noodles. The two screws are divided into two levels, and the horizontal column is applied with two levels; the load is 8000.
2 Calculation Model and Calculation Results Determining the calculation model is an important step in finite element analysis. The finite element calculation model of the machine column is established with a 3å©0 pre-processing program. For dimensional models, finite element models can be generated automatically or semi-automatically, no matter how complex the structure is. The simpler dimensional object can be used to recapture the rotation in the program based on the dimensional model. Functions such as mapping and bonding generate dimensional finite element networks. However, if the complex structure is such as a column, the above method cannot be used, and another way must be found.
The 310 melon program can be passed. 0, format file and person plus, tax software for data exchange. Therefore, the surface geometry model of the column is established by using the addition and tax software, and then the finite element calculation model is generated. The steps are as follows: 1. Add the software, and the command in the software to establish the geometric cast of the traitor. 2 is divided into face meshes by using 3å©6 type blocks. 3 Then use this program to create a dimension finite element mesh of the column.
In the modeling process, under the premise of faithfully reflecting the main mechanical characteristics of the machine column structure, in order to simplify and facilitate the modeling, to appropriately reduce the model law, some individual local areas of the column structure are simplified. There are many small diameter holes on the upper and lower platforms of the column. There are also two slots for the sliding guide rails on the upper and lower stages. These have little stiffness to the entire column, so it is neglected. The Getai at the edge of the table is small in size compared to the platform, and they are removed when the mold is reached.
In addition, the rounded corners at the front and rear side wall openings are replaced by right angles, although stress concentration may occur at right angles, but the columns are small.
Since the shape of the column structure is complicated, it is necessary to divide the column into several blocks, and then respectively generate a mesh model for each block, and then connect the blocks with a 1 ping command. From the beginning, there is a Yangsuo raft in the last stalk. Shuttle, considering that most of the pillars are symmetric about the center plane, separate the asymmetrical part, symmetrical half, then copy the other half with the mirror, and then connect the asymmetrical part, which can greatly reduce the modeling. The amount of work. The following is an example of a non-reinforced rib column to illustrate the specific over-privateness of the model. 1. First use the human 0 command to merge the 1. peptide into the wall and merge with the base. 23. Because of the geometrical model of each part of the column It is built by the person and tax software in the overall coordinate system. When generating each part of the finite element model, the same unit size is defined. Therefore, the finite element mesh of the side wall and the base is combined to ensure the connection. The nodes at the corresponding correspond, and the overlapping redundant nodes are automatically deleted. Reuse; command to connect the top and right side walls, 2 then use the mirror command to copy the other half of the model, 2. Cambodia 1 Ke called. 1 command will not be called on the front and rear side walls, the Mo type is connected, forming the whole, the limit element calibration, such as winter 2, in the generation of the dimension finite element mesh, pay special attention to the loss of the unit. The so-called unit loss means that it looks like a unit in a 5-port 1-pass program, but in fact the decoder does not use it as a unit, and it can be recessed there with a 5å©6 boundary post-processing program. The hole. The occurrence of unit loss may be due to the fact that one or more sides are composed of multiple line segments; 2 purchases are not intersecting at the same point; 3 or more sides are longer sections of the line ç¿ 1 Weng selection, Wei 1 Plow, confuse, prepare; Fusuo sloping basin through the choice of heat-foster, plate, Sjwww! 2 The woman's strong fat column has a magnifying display command to process the program to find out the cause, and then modify it with the modify command. For example, an edge consisting of multiple line segments, you can use the delete command to remove the extra line segments; if the edges are not intersecting at the same point, use the move command to make the edges intersect.
According to the method described above, the generated finite element network model of the column 3. The model has a total of 29 899 nodes, 1709 outer units, of which 4 nodes are 22 facet units, 8 nodes are hexahedral units 16 406, 567 nodes The transition units are 57533 and 77 respectively.
The column and the base are connected by 16 bolts, and the vertical direction of the node at the position and the horizontal displacement in the paper plane are restrained, and the displacement of the contact surface between the bottom boss of the column and the rolling screw is perpendicular to the direction of the paper surface. After the column finite element model is established, the profit structure analysis software 1. From the power analysis module of 13 scores the Guangli column Chengzhi soil. The knife looks for stiffness and strength. The calculation is performed on a 32 mega 586 microcomputer with a calculation time of approximately 6.
Through calculation and analysis of the result shape, the column has the largest displacement in the vertical direction, the vertical direction is the second, and the horizontal displacement in the paper is the smallest, but the value is very small, and the maximum equivalent displacement is 1. Hey, on the top of the column, about 300 from the left end. The Misesian stress at the base of the column is 30 rivers, which is the maximum stress. The design index pursued by mechanical product design is to make the product the lightest weight under the performance constraints such as stiffness strength. From the above analysis, the deformation and stress level of the column are very low, that is, there is a very large margin in terms of stiffness and strength, indicating that too many reinforcing ribs are arranged on the column. Then, in order to ensure that the column has sufficient rigidity and strength, how to arrange the reinforcing ribs and reduce the quality of the column as much as possible, it needs to be solved by structural optimization. This is a more complicated question. This article does not provide a scientific basis for the improved design of the 祜 祜 付 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45
According to the calculation results, the static stiffness is less than the allowable static deformation of the machine column.
When the machine tool is working, the column is subjected to alternating cutting load, so the column should be subjected to dynamic analysis and fatigue calculation, so as to fully understand the stiffness characteristics of the column. Based on this, the structural optimization design is carried out to meet the design requirements of lightweight products.
1 Zhu Yiwen, Wei Qingru, Gu Boda. Microcomputer finite element before and after processing system, 0.0 and its application Beijing Science and Technology Literature Publishing House, 1993.
2 Zhu Yiwen. 10 feet of people calculate the module data file grid by software analysis. Tianjin Institute of Surveying and Design, Tianjin Hydropower, 1991.
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