How can CNC machining improve the machining accuracy and efficiency of the workpiece?
Release time:
2019-08-23
Under the condition that the rigidity allows, the rough machining takes a larger cutting depth to reduce the number of passes and improve the productivity of the workpiece; the finishing generally takes a smaller cutting depth to obtain a higher surface quality. Affect the final machining accuracy and processing efficiency of the workpiece, in addition to the CNC machine tool itself, but also from the reasonable processing route settings, tool selection and correct installation, cutting amount of reasonable choice, programming skills and dimensional accuracy of rapid control and other aspects of comprehensive consideration.
1. programming skills
Numerical control programming is the most basic work of numerical control processing, and the advantages and disadvantages of the workpiece processing program directly affect the final machining accuracy and processing efficiency of the machine tool. From the clever use of inherent procedures, reduce the cumulative error of the numerical control system, flexible use of the main program and subroutine and other aspects.
1, flexible use of the main program and subroutine.
In the complex mold processing, the general use of a mold in the form of multiple parts for processing. If there are several identical shapes on the mold, the relationship between the main program and the subroutine should be used flexibly, and the subroutine should be called repeatedly in the main program until the processing is completed. It can not only ensure the consistency of the processing size, but also improve the processing efficiency.
2, reduce the cumulative error of the numerical control system.
Generally, the workpiece is programmed in an incremental manner, which is processed based on the previous point. Such continuous execution of multi-segment programs will inevitably produce certain cumulative errors. Therefore, absolute programming is used as far as possible during programming, so that each program segment is based on the origin of the workpiece, thus reducing the cumulative errors of the numerical control system and ensuring the machining accuracy.
Machining accuracy is mainly used to produce products, and machining accuracy and machining error are terms for evaluating the geometric parameters of the machined surface. However, the actual parameters obtained by any processing method will not be absolutely accurate. From the function of the part, as long as the processing error is within the tolerance range required by the part drawing, it is considered that the processing accuracy is guaranteed.
Machining accuracy refers to the degree to which the actual geometric parameters (size, shape and position) of the parts after processing can help you conform to the ideal geometric parameters if you want to learn UG programming and receive learning materials in group 496610960. The difference between them is called machining error. The size of the machining error reflects the level of machining accuracy. The greater the error, the lower the machining accuracy, and the smaller the error, the higher the machining accuracy. The following is a brief introduction to improve the accuracy of the workpiece processing methods:
1. adjustments to the process system
(1) The trial cutting method is adjusted by trial cutting-measuring the size-adjusting the amount of cutting tools-cutting by cutting-trying to cut again, and so on until the required size is reached. This method has low production efficiency and is mainly used for single-piece small batch production.
(2) The adjustment method obtains the required size by adjusting the relative positions of the machine tool, fixture, workpiece and tool in advance. This method has high productivity and is mainly used for mass production.
2. reduce machine tool error
(1) The rotation accuracy of the bearing should be improved:
① Selection of high-precision rolling bearings;
The use of high-precision multi-oil wedge dynamic pressure bearings;
The use of high-precision hydrostatic bearings
(2) Improve the accuracy of the parts with the bearing:
① Improve the machining accuracy of the box support hole and the spindle journal;
Improve the machining accuracy of the surface matching with the bearing;
③ Measure and adjust the radial runout range of the corresponding parts to compensate or offset the error.
(3) Appropriate pre-tightening of rolling bearings:
① Clearance can be eliminated;
② Increase bearing stiffness;
③ Average rolling element error.
(4) the spindle rotation accuracy is not reflected on the workpiece
3. Reduction of Transmission Error of Transmission Chain
(1) The number of transmission parts is small, the transmission chain is short, and the transmission accuracy is high;
(2) The use of reduced speed transmission is an important principle to ensure transmission accuracy, and the closer to the end of the transmission pair, the smaller the transmission ratio should be;
(3) The accuracy of the end piece should be higher than that of other transmission parts.
4. reduce tool wear
(1) The tool must be re-sharpening before the tool size wear reaches the sharp wear stage.
(2) Selection of special cutting oil for full lubrication
(3) the tool material should meet the process requirements
5. reduce the force deformation of the process system
(1) Improve the rigidity of the system, especially the rigidity of the weak links in the process system;
(2) Reduce the load and its changes
6. Reduction of Thermal Deformation of Process System
(1) Reduce the heat source and isolate the heat source
(2) Equilibrium temperature field
(3) Adopt reasonable machine tool component structure and assembly benchmark
(4) Accelerate to achieve heat transfer balance
(5) Control the ambient temperature
7. reduction of residual stress
(1) Increase the heat treatment process to eliminate internal stress;
(2) Reasonably arrange the process.
The above is the method to reduce the error of the workpiece, and the reasonable arrangement of the process can effectively improve the accuracy of the workpiece.
2. reasonable setting processing route
Reasonable setting of processing route and processing sequence is an important basis for optimizing the programming of workpiece processing. It can be considered in terms of the machining path and the feed method.
In CNC milling of workpieces, if you want to learn UG programming to receive learning materials in group 496610960, it can help you to choose the appropriate feeding method according to the technological requirements of workpieces, so as to ensure the cutting accuracy and processing efficiency of workpieces. When milling the outer contour of the plane workpiece, the cutting tool should be arranged to cut in and out of the route. Try to cut in and out along the extension line of the contour curve to avoid knife marks at the junction. At the same time in the milling process should be selected according to the workpiece milling or reverse milling.
Selection and correct installation of 3. tools
Whether it is CNC machining or ordinary machining, the tool is directly acting on the workpiece, so its selection and installation of the workpiece machining accuracy and surface quality of the most important factors. In particular, the workpiece is processed on the CNC machining center, and the tools are stored in the tool magazine in advance. Once the processing is started, it must not be replaced at will. Therefore, the general principle of tool selection is: easy installation and adjustment, good rigidity, durability and high precision.
Reasonable Selection of 4. Cutting Amount
The determination of cutting amount is an important part of CNC machining process, and its size is an important parameter of the main motion and feed motion of the machine tool, which has an important influence on the machining accuracy, machining efficiency and tool wear of the workpiece. The selection of cutting parameters includes cutting speed, back cutting amount and feed rate. The basic selection principle is: under the condition of stiffness, roughing to take a larger cutting depth to reduce the number of passes and improve the productivity of the workpiece; finishing generally take a smaller cutting depth to obtain a higher surface quality.
Previous Page
Next Page
Previous Page
Next Page
Mobile Website
WeChat Applet
CopyRight © 2024 Dongguan Yongfei Hardware Products Co., Ltd. All rights reserved