At present, numerical control machining can not get rid of the fate of the industry in the modern era, and there will be some errors in the process of machining
- Wrong processing principle
The main error of CNC machining is caused by approximate machining motion or approximate tool profile. Because of the error of machining principle, it is called machining principle error. As long as the main error is within the allowable range, this type of processing is still feasible.
- Geometric error of machine tool
Machining error, installation error and wear during use directly affect the machining accuracy of the workpiece. It includes the rotation of the spindle, the linear motion of the guide rail and the error of the transmission chain.
- Manufacturing error and wear of tools
The manufacturing error, installation error and wear of CNC machining tools in the process of machining will affect the machining accuracy of the workpiece. In the cutting process, the cutting edge, cutting surface, workpiece and chip produce strong friction, which leads to tool wear. When the tool wear reaches a certain value, the surface roughness of the workpiece increases, and the color and shape of the chip change. With the vibration, the tool wear will directly affect the cutting productivity, processing quality and cost.
- Fixture error
CNC machining fixture error includes positioning error, clamping error, fixture installation error and tool setting error. These errors are mainly related to the manufacturing and assembly accuracy of the fixture. CNC machining accuracy is not perfect, as long as the error is controlled in a certain range, it will not have any significance. Tool manufacturing error and wear.
- Positioning error
Positioning error mainly includes reference misalignment error and locator manufacturing error. When machining the workpiece on the machine tool, several geometric elements on the workpiece must be selected as the positioning reference. If the selected positioning reference and design basis are used (reference is used to determine the table on the part drawing)
Face size and location). If misalignment occurs, a reference misalignment error will occur. The positioning surface of the workpiece and the positioning part of the fixture form a positioning pair. Large displacement of workpiece caused by inaccurate positioning position and matching gap between positioning pairs is called positioning. Sub manufacturing inaccuracy
Wrong. The inaccuracy in positioning and manufacturing only occurs when the adjustment method is used, and will not occur in the trial cutting process.
- Adjustment error
In each process, the process system is always adjusted in some way. Because the adjustment is impossible to be accurate, there is an adjustment error. In process
In the system, by adjusting the machine tool, cutter, fixture or workpiece, the mutual position accuracy of workpiece and cutter on the machine tool is ensured. When the original accuracy of machine tool, tool, fixture and workpiece blank meets the process requirements without considering the dynamic factors, the adjustment error plays a decisive role in the machining error.
- Measurement error
When measuring parts during or after machining, the measurement accuracy is directly affected by the measurement method, measuring tool accuracy, workpiece and subjective and objective factors. To a certain extent, the above seven machining errors can be avoided, so the operators who need to process can test the six machining processes that may cause machining errors more carefully. After machining operation, the influence of machining error can be reduced better.
The above is for you to share the “CNC processing to pay special attention to a few places.”.
ken. tang@chengcg.com
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