CNC milling machines are common machining equipment. In the process of CNC milling, the accuracy of the processed parts is affected by many factors. If corresponding methods are not taken to solve it, the size and shape of the processed parts may not meet the design requirements of the drawings, thereby affecting the quality of the final product.
In order to address these influencing factors, CNC milling machine operators need to have a comprehensive understanding of the factors that affect the machining accuracy of CNC milling machines, and analyze the relevant factors after a large number of actual machining operations. By using reasonable solutions to reduce or even eliminate the impact of these factors, the accuracy of CNC milling machine parts can be ultimately improved.
1、 Factors affecting the machining accuracy of CNC milling machines
The factors that affect the machining accuracy of CNC milling machines can be roughly analyzed from the following three aspects: the accuracy of the CNC milling machine equipment body, the use of blanks for machining parts, and the numerical values of various milling parameters used in the milling process.
1. Accuracy of CNC milling machine equipment body
CNC milling machines are common machining equipment, and the machining accuracy of their parts is affected by multiple factors, such as the accuracy of CNC systems and bed guide rails. Nowadays, many domestic factories produce CNC machine tools by introducing foreign CNC systems and using their own production bed and assembly methods, which undoubtedly increases assembly errors.
Whether the performance of CNC machine tools is stable, whether their rigidity meets the standard, and whether they can withstand mechanical vibrations during the processing will all affect product quality. Therefore, in order to improve the machining accuracy of parts, the accuracy of the CNC milling machine body must be guaranteed.
2. Blank and error impact of parts
The measurement errors generated by the milling cutter during milling processing can also affect the machining accuracy of CNC milling machines. The tools used in CNC milling machines involve various factors, including tool material, tool size, and tool alignment angle. If the tool parameters used cannot match the material being milled, errors will occur during the machining process, making it impossible to ensure the accuracy or surface roughness of the processed parts.
The forces that CNC milling machines bear when processing different parts are also different. This results in varying sizes of gaps between bearings, which affects the accuracy of the parts and reduces the accuracy of CNC milling machines.
3. Impact of cutting amount
In the process of milling parts, the rotation speed, cutting depth, feed rate, milling speed and other factors of the tool are important parameters. The actual application methods of cutting parameters selected for different parts also vary, reflecting differences in precision, size, roughness, and other aspects in part quality.
Before using a CNC milling machine for part processing, it is necessary to combine the equipment, tools, and drawings marked with part dimensions to scientifically and reasonably select the necessary conditions for processing parts.
2、 A Solution to the Precision Problem of CNC Milling Machine Processing Parts
The operating experience of CNC milling machines requires a long period of actual processing operations to gradually accumulate. Operators need to summarize their own methods to address the accuracy error problem of processing different types, materials, and sizes of parts, mainly adopting the following methods.
1. Reference plane positioning for blank clamping
Due to the fact that CNC milling machines often process various shapes of parts during the machining process, and are made of rough rough surface materials such as cylinders, squares, spheres, etc.
This material itself has significant errors, which can reduce processing accuracy during the processing process. In this case, the problem of machining accuracy can be solved by determining the positioning of the reference plane, and it can also facilitate the operator to measure the size of the parts and improve the machining accuracy of the parts.
2. Take measures to control the temperature of the equipment
During the process of machining parts on a CNC milling machine, the associated bearing parts on the milling machine will rub against each other, generating considerable heat. The heat generated by the mechanical equipment itself is combined with the heat generated by the friction between the cutting tool and the workpiece during the milling process. This accelerates the temperature rise of the processed parts, and in this state, if the milling machine equipment cannot dissipate heat in a timely manner, the processed parts will undergo deformation.
For this reason, CNC milling machines need to install suitable heat dissipation devices to increase the heat dissipation area of the equipment, so that during the operation of the CNC milling machine, it can self dissipate heat, reduce the operating temperature of the equipment and the possible deformation problems of the processed parts. This can also play a crucial role in reducing processing errors and further improving the accuracy of the processed parts.
3. Perform error compensation during part processing
During the milling process using a CNC milling machine, there may be some accuracy issues with the parts, which affect the machining quality. In this case, error compensation methods can be used. When using relevant error compensation, the following two methods can be considered.
Method ①: If the operating system of a CNC milling machine has reverse deviation issues, error compensation is required. Machine tool operators can apply CNC programming to locate certain units at the beginning of processing, thereby achieving error compensation, eliminating reverse deviations, and ensuring the machining accuracy of CNC milling machines.
Method 2: Through CNC programming, accurate positioning during milling can be achieved, and CNC milling machine interpolation can be achieved without changing the body of the CNC milling machine. Interpolating the gaps between the bearings of the CNC milling machine body when it leaves the factory, and timely replenishing the gaps caused by vibration or force during the operation of the CNC milling machine, plays a crucial role in reducing machining errors and improving the machining accuracy of the parts.
4. Supervision during the operation of CNC milling machines
The guarantee of machining accuracy of CNC milling machines also relies on the supervision and management of equipment usage sites. Effective supervision and management can reduce many problems during the machining process. Monitoring the actual operators on site can timely detect improper operations, help operators correct them in a timely manner, ensure their error free use, and thus improve the processing quality of parts.
Improving machining accuracy is a long-term exploration process that requires continuous exploration and analysis of the factors that affect machining accuracy, adopting reasonable methods to improve machining accuracy, and ultimately ensuring that the dimensions of the parts meet the design requirements of the drawings, satisfying customers with the quality of the parts.
