Research on thermal deformation control methods and technologies in auto parts processing
Release Time : 2024-12-19
In the auto parts processing process, thermal deformation is one of the key factors affecting processing accuracy. Due to the generation and accumulation of cutting heat, friction heat and other heat, parts will undergo dimensional changes and shape distortion, reducing product quality. Therefore, it is of extremely important significance to conduct in-depth research on thermal deformation control methods and technologies.
Reasonable selection of cutting parameters such as cutting speed, feed rate and cutting depth can effectively reduce heat generation. Lower cutting speed can reduce the cutting heat generation rate, but may affect production efficiency, which needs to be weighed comprehensively. Appropriate reduction of feed rate and depth of cut can also help control cutting forces and heat. For example, when processing high-precision automobile engine blocks, the best combination of cutting parameters can be determined through experiments, which can significantly reduce the impact of thermal deformation on the cylindricity of the cylinder bore.
It is crucial to adopt efficient cooling and lubrication methods. The traditional pouring cooling effect is limited, and new spray cooling, minimum quantity lubrication cooling and other technologies have emerged as the times require. Spray cooling can spray coolant into the processing area in the form of mist to enhance the heat exchange effect. Minimum quantity lubrication cooling uses a small amount of lubricating oil and high-pressure gas to mix and spray, which can reduce heat and improve the surface quality of the machine. In the processing of automobile transmission gears, the application of minimum quantity lubrication cooling technology not only reduces thermal deformation, but also reduces tool wear.
Choosing tool materials with high thermal conductivity and good heat resistance, such as ceramic tools, cubic boron nitride tools, etc., can speed up the conduction of heat away from the cutting area. At the same time, optimizing the geometry of the tool, such as increasing the rake angle, can reduce cutting force and heat generation, and rationally designing the cutting edge radius and relief angle of the tool can reduce the friction heat between the tool and the workpiece. For example, in the processing of automobile brake discs, new ceramic tools are used and their geometric parameters are optimized to effectively control thermal deformation and improve the flatness of the brake disc.
Reasonably arrange the processing sequence and separate roughing and finishing. The large amount of heat generated during roughing has time to dissipate, reducing the impact on finishing. For example, rough turning and rough grinding of an automobile crankshaft are performed first, and then fine turning and fine grinding are performed after the workpiece has cooled. This can effectively improve the machining accuracy of the crankshaft and reduce the journal cylindricity error caused by thermal deformation.
By installing temperature sensors on machine tools or processing equipment, the temperature changes of key parts are monitored in real time, and the thermal deformation is calculated using the established thermal error model. The control system then compensates for the position of the tool or workpiece. In CNC machining of automotive parts, thermal error compensation technology can significantly improve machining accuracy, and the compensated machining dimensional deviation can be controlled within a very small range.
Thermal deformation control during auto parts processing requires the comprehensive use of multiple methods and technologies. From cutting parameter optimization to cooling and lubrication improvement, from tool optimization to process adjustment and thermal error compensation, good results can only be achieved by the cooperation of all links. In the future, with the continuous development of material science, sensing technology and control technology, thermal deformation control technology will be more accurate and efficient, further promoting the improvement of auto parts processing quality and production efficiency.