Factors Affecting the Machining Precision of CNC Lathes
Position error refers to the amount of variation or deviation of the mutual position between the actual surface, axis, or plane of symmetry of the part relative to its ideal position after machining, such as perpendicularity, position, and symmetry.
The position error in CNC machine tool machining usually refers to the dead zone error. The main reason for the position error is the machining error caused by the gap and elastic deformation during transmission when the machine tool parts are machining.
And in machining, the cutter head of the machine tool needs to overcome friction and other factors to cause position errors. In the open-loop system, the position accuracy is greatly affected. In the closed-loop servo system,
It mainly depends on the accuracy of the displacement detection device and the speed amplification factor of the system, and generally has a small impact.
Machining accuracy errors due to geometric errors in CNC lathe machining:
In the machining of CNC lathes, the geometric accuracy of the lathes is affected due to the influence of external factors such as external forces and heat generated during machining.
The parts machining on the lathe are geometrically deformed, which leads to geometric errors.
According to research, the main reasons for geometric errors of CNC lathes are the following two: internal factors and external factors.
The internal factor of the geometric error of the lathe refers to the geometric error caused by the factors of the machine tool itself.
Such as the level of the working surface of the lathe, the level and straightness of the guide rail of the lathe, the geometric accuracy of the lathe tool and fixture.
External factors mainly refer to geometric errors caused by factors such as the external environment and thermal deformation during machining. For example, during the cutting process of a tool or component,
Due to thermal expansion and deformation, geometric errors occur, which affects the machining accuracy of the lathe and the machining accuracy of parts and components.
Machining accuracy error due to lathe positioning in CNC lathe machining:
According to long-term data analysis and practical operation of parts machining, it can be seen that the positioning of the lathe has a greater impact on the machining accuracy of the CNC lathe.
From the structural point of view, the machining errors of CNC lathes are mostly caused by positioning accuracy, and the feed system of the lathe is the main link that affects the positioning accuracy.
The feed system of CNC lathes usually consists of two parts: mechanical drive system and electrical control system. The positioning accuracy is related to the mechanical drive system in the structural design.
In closed-loop systems, CNC lathes can usually prevent positional deviations of main components in the feed system, such as ball screws, through positioning detection devices.
For the open-loop system, due to the many influencing factors and the complicated situation, positioning monitoring cannot be performed, so the machining accuracy of the CNC lathe has a greater impact.
Countermeasures to improve the machining accuracy of CNC lathes:
Improve machining accuracy by controlling the raw error of CNC machine tools
Reasonably design the core components of the machine tool to avoid positioning errors
Improving the machining accuracy of CNC machine tools through real-time monitoring technology
With the continuous improvement of numerical control technology, the real-time monitoring of the whole process of the CNC lathe is monitored, and the error link in the machining process is adjusted in time.
The error data of each link in the machining process is collected and fed back to the control terminal, and the corresponding error compensation mechanism is adopted through the error data.
The timely error compensation can effectively improve the machining accuracy of parts.
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