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Analysis of Influencing Factors for the Machining Accuracy of CNC Lathes and Countermeasures

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With the rapid development of social economy and the improvement of science and technology, customers’ requirements for lathe processing accuracy have also increased. As an advanced mechanical processing technology, the application of CNC lathe has promoted the effective improvement of mechanical processing production quality and efficiency.

However, since CNC lathes are often affected by various internal and external factors during operation, the processing accuracy of CNC lathes cannot meet the design requirements. Therefore, when mechanical processing enterprises use CNC lathes to process mechanical parts, operators should adopt targeted prevention strategies based on in-depth analysis of the factors affecting the processing accuracy of parts to ensure that the processing accuracy of CNC lathes meets the design standards and requirements of mechanical processing.

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Composition and working principle of CNC lathes

 

During operation, CNC lathes mainly use advanced CNC programs to achieve the purpose of stable processing of rotating workpieces and shaft workpieces, and promote the effective improvement of workpiece processing quality and efficiency. Since the requirements for processing precision of parts produced in batches are relatively higher, therefore, the CNC lathe operators of mechanical processing enterprises should reasonably use information technology means such as numbers, letters, and symbols to complete the design of automatic control programs before the start of part processing, and then input the pre-compiled programs into the automatic control system of the CNC lathe to ensure the smooth progress of part processing.

After the start of part processing, the CNC lathe operator collects and analyzes the data of the CNC lathe operation, and converts it into digital, coded and other forms, and then the computer in the main control system of the CNC lathe performs corresponding processing, and issues execution instructions for part processing to the actuator of the CNC lathe to drive the normal and orderly operation of the CNC lathe.

After the part processing process is completed, the main control system of the CNC lathe issues instructions to ensure that each actuator of the CNC lathe returns to the initial processing position, thereby effectively improving the processing precision of the parts.Since the processing precision of the CNC lathe has a decisive influence on the quality and efficiency of mechanical manufacturing, the operator must have professional technicians write the CNC processing program before the start of CNC processing to ensure the smooth completion of the automatic processing process of the workpiece.

With the continuous development and application of information technology, people’s requirements for the production quality and precision of mechanical manufacturing products are becoming higher and higher. Since traditional mechanical processing technology can no longer meet the current customer requirements for the processing accuracy of mechanical parts, mechanical processing companies should actively explore and research the application strategies of CNC processing technology in the field of mechanical processing, improve the accuracy of mechanical processing, and produce mechanical products with higher precision.

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Quality factors affecting the machining accuracy of CNC lathes

 

CNC lathe machining is a machining method that uses high-precision and high-efficiency automated lathes to control the movement of parts and machining tools through digital information. The machining accuracy of CNC lathes refers to the degree to which the actual geometric parameters of the machined parts are consistent with the ideal geometric parameters specified in the drawings. The higher the degree of consistency between the actual geometric parameters of the machined parts and the ideal geometric parameters specified in the drawings, the higher the machining accuracy of the CNC lathes. There are many factors that affect the machining accuracy of CNC lathes, mainly the following points.

1. Lathe quality factors

 

During the operation of CNC lathes, the factors that affect the machining accuracy of parts mainly come from human, equipment, accidents and other aspects. Among them, the problems of the CNC lathe itself are one of the most critical factors affecting the machining accuracy of the workpiece. During the operation of the CNC lathe, once there is a problem with the configuration of the CNC lathe system, the workpiece will not meet the accuracy standards. Therefore, when operating a CNC lathe, the operator must take active and effective measures to control the stability and rigidity of the CNC lathe itself, so as to avoid operational abnormalities and errors in mechanical operation due to insufficient rigidity or stability of the CNC lathe, which will affect the quality and accuracy of workpiece processing.

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2. Raw materials and error factors

 

During the operation of CNC lathes, tool setting angles and measurement errors are also common important factors affecting the machining accuracy of machine tools. Since the tools used in CNC lathes have clear requirements for size, angle, etc., operators choose and use different tools for different types of materials of parts to be processed. In addition, during the operation of CNC lathes, the size and angle of the tool itself will change. Therefore, once the size and tool setting angle of the CNC lathe tool deviate, it will inevitably affect the machining accuracy of the workpiece.

According to relevant survey data, most of the CNC machine tools used in most mechanical processing companies in China currently use motors to drive ball screw transmissions to achieve feed. During the workpiece processing of CNC lathes, it is inevitable that there will be large gaps between the bearings under the influence of external forces, resulting in comprehensive errors on the front and back sides of the workpiece, affecting the machining accuracy of the workpiece and reducing the efficiency of CNC machining.

3. Cutting amount factor

 

Before a machining enterprise uses a CNC lathe to process a workpiece, the CNC lathe operator must reasonably select the processing tools according to the characteristics and srequirements of the parts to be processed, so as to promote the accuracy of CNC processing while ensuring the quality of the workpiece. For example: when selecting a tool, the operator must fully consider the impact of cutting factors such as back cutting amount, feed rate, spindle speed, etc, on the processing accuracy of the parts, and adopt different response strategies based on this to ensure that the accuracy of the CNC processed workpiece meets the design standards and requirements.

In addition, if the parts to be processed have clear requirements for processing accuracy, the CNC lathe operator should choose a processing method that meets the requirements according to the accuracy standard of the workpiece to be processed, so as to avoid affecting the accuracy of the parts processing due to unreasonable workpiece processing methods.

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Measures to improve the processing accuracy of CNC lathes

 

1. Strengthen lathe maintenance management

 

In order to ensure the efficient operation of CNC lathes, operators must implement the window inspection and maintenance system in all aspects of CNC processing during the CNC processing process. Use the built-in program of the CNC lathe to analyze and process the CNC processing data information, and then replace the props required by the CNC processing by detecting the spindle to ensure that the accuracy of CNC processing meets the design standards and requirements of the workpiece accuracy.

When implementing the regular inspection and maintenance work system of CNC lathes, operators should strictly follow the requirements to do a good job in real-time monitoring and lubrication of the oil level and sliding parts of the CNC lathe, so as to effectively improve the operation efficiency of the CNC lathe.

During the operation of the CNC lathe, the operator should regularly check the possible heating of the CNC lathe and clean the debris left in the filter. Once the CNC lathe rotating device fails, the lathe should be stopped immediately, and then the residue should be cleaned in time, and the filter should be replaced to improve the processing accuracy of the CNC lathe. In addition, due to the inseparable connection between the external motor system and the CNC lathe system, the operator must regularly check the operating status of electrical plugs and sockets during the operation of the CNC lathe to avoid failures in the electrical equipment of the CNC lathe and affect the accuracy of CNC machining.

2. Strengthen the overall design of CNC lathes

 

In the process of development and progress of CNC mechanical technology, CNC lathes should also speed up the pace of optimization work in overall design. Through the innovation of CNC structure, the optimization and upgrading of CNC lathe configuration can be completed, the stability and reliability of CNC lathe operation can be improved, the production cost of mechanical processing enterprises can be reduced, and the precision of CNC processing can be ensured to meet the design standards and requirements.

When optimizing the overall configuration of CNC lathes, operators should pay full attention to the importance of deformation stress detection, strictly follow the stress generated when different accessories are used, formulate scientific and reasonable optimization strategies, and improve the precision of CNC lathe processing by thoroughly improving the deformation problem of lathes.

In order to improve the efficiency of swing frequency monitoring during CNC processing, operators should reasonably adjust and optimize the structure of CNC machine tools on the basis of ensuring that the objective situation inspection and monitoring system is implemented in all aspects of CNC processing, which not only ensures the rigidity of CNC machine tool operation and reduces the consumption of CNC processing materials, but also achieves the purpose of stabilizing the center of gravity of CNC lathes and improving the precision of CNC processing.

During operation, since the CNC lathe lacks an ideal heat dissipation device, once the various components of the spindle are running, the interrelated bearings rub against each other, which will not only generate a large amount of heat, but also merge with the heat generated by the equipment during the CNC lathe cutting process, causing the CNC lathe spindle to experience a rapid increase in temperature, increasing the incidence of thermal deformation problems in the CNC lathe spindle, and affecting the accuracy of CNC processing.

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The thermal deformation problem that occurs during the operation of the CNC lathe is characterized by instability and irregularity. If the CNC lathe has a thermal deformation problem, it will inevitably cause the CNC lathe spindle to have an elongated and skewed axis, which will cause the CNC lathe spindle to have a disordered operation, seriously affecting the accuracy of CNC lathe processing.

To address this problem, mechanical processing companies should set up a heat dissipation device at the spindle position of the CNC lathe to increase the spindle heat dissipation area and improve the heat dissipation performance of the spindle, so as to achieve the purpose of reducing the spindle operating temperature and the incidence of thermal deformation problems, and reduce the adverse effects of processing errors on the processing accuracy of workpieces.

3. Perform error compensation to achieve precision control

 

The semi-closed-loop servo system is the core of driving the operation of CNC lathes. Due to the reverse deviation phenomenon during the operation of CNC lathes, this has a decisive impact on the positioning accuracy of CNC lathes and the subsequent part processing quality. In this regard, operators should adopt error compensation methods during the operation of CNC lathes to compensate for the impact of such problems on the processing accuracy of parts.

Through the analysis of the accuracy of CNC lathes currently used in China’s machinery manufacturing field, it is found that mechanical processing companies should adopt programming methods according to the design standards and requirements of CNC processing accuracy to improve mechanical processing accuracy, give full play to the advantages of directional operations, and improve the accuracy of CNC processing.

In view of the phenomenon of running trajectory changes after a certain axis receives a control command during the operation of CNC lathes, operators should use CNC equipment reasonably, read the reverse clearance value during the operation of CNC lathes from time to time, adjust the coordinate displacement instructions and data, and then transmit the positioning data that meets the processing accuracy requirements to the control center of the CNC lathe, which can effectively reduce the impact of reverse deviation on part processing accuracy.

4. Apply programming to improve geometric accuracy

 

During the operation of the CNC lathe, if the equipment reaches the position of the interpolation starting point, the pre-edited program can be applied to complete the processing of the parts. Interpolation in CNC machining is actually a method of correcting the position by reverse interpolation for the positive deviation generated during the operation of the CNC lathe, so as to improve the stability and reliability of the operation of the CNC lathe. Usually, during the operation of the CNC lathe, the operator should complete the interpolation of each bearing gap by setting up different storage addresses to minimize the impact of bearing deviation on CNC machining accuracy.

If the equipment operation instructions change during the operation of the CNC lathe, the interpolation between each bearing will inevitably change. Therefore, in order to improve the accuracy of system data reading, the operator must implement the programming correction strategy to achieve the purpose of effectively reducing CNC machining deviations and promoting the effective improvement of CNC lathe machining accuracy.

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Conclusion

 

In short, with the rapid popularization and application of CNC lathe processing technology, the quality and efficiency of CNC processing is also increasingly high. CNC lathe operators, should be reasonable use of advanced technical means, optimize and improve the CNC lathe processing system to ensure that the CNC lathe always maintains a highly efficient operation of the state, in order to effectively promote the accuracy of CNC lathe processing.

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