In mechanical processing, surface finish is one of the important indicators for measuring part quality, especially having a decisive impact on precision manufacturing and high-precision equipment. Turning, as one of the most common metal cutting processes, directly affects the performance, service life, and assembly accuracy of the workpiece. Therefore, how to effectively improve surface finish during the turning process is a focus of attention for every process engineer and technician.



I. Reasonably selecting tool material and geometric parameters



The tool is one of the most critical factors in turning processing. Different tool materials have a direct impact on surface finish. For example, high-speed steel (HSS), carbide, ceramic tools, and cubic boron nitride (CBN) materials each have their characteristics. Carbide is widely used in precision turning with high surface finish requirements due to its good wear resistance and high temperature hardness. In addition, the geometric parameters of the tool such as the rake angle, clearance angle, main cutting edge angle, minor cutting edge angle, and tip radius should also be reasonably selected. Increasing the tip radius helps to reduce cutting force and surface roughness, improving the finish.



II. Optimizing cutting parameters

　　Cutting speed, feed rate, and depth of cut are the three basic parameters that affect surface finish. Generally, increasing the cutting speed can reduce the generation of built-up edge, thereby improving surface quality. However, an increase in feed rate will directly lead to an increase in surface roughness, so a smaller feed rate should be used during the precision processing stage. At the same time, the depth of cut should also be controlled within a reasonable range to avoid vibration caused by excessive cutting force, which in turn affects the surface quality.



III. Using cooling and lubricating fluids



Cooling and lubricating fluids not only effectively reduce the temperature of the cutting area but also reduce friction and improve the chip removal effect, thereby significantly improving surface finish. The selection of appropriate cutting fluid types (such as emulsion, cutting oil, or synthetic fluid) and reasonable supply methods (such as high-pressure jetting) has a positive effect on improving the quality of the processed surface.



IV. Ensuring the stability of the machine tool and fixture



The rigidity of the machine tool, the accuracy of the guideways, the rotational accuracy of the spindle, and the clamping stability of the fixture all affect the surface quality. During the turning process, if the machine tool has vibration or clearance, it is easy to cause surface waves or marks. Therefore, it is necessary to maintain the equipment regularly to ensure its good condition, and vibration reduction devices or improved fixture design can be used to enhance the system rigidity if necessary.



V. Adopting advanced processing technology and processes



With the development of numerical control technology, the use of CNC lathes for precision processing has become an important means to improve surface finish. By programming control of feed and speed, high-precision and high-stability continuous cutting can be achieved. In addition, the application of advanced processes such as ultra-precision turning, mirror turning, and micro-lubrication (MQL) also provides more possibilities for improving surface finish.



Conclusion:

　　Improving the surface finish of turning processing is a systematic project, involving tools, parameters, cooling, equipment, and processes, among many other aspects. By scientifically and reasonably selecting tools and parameters, optimizing the processing environment and process flow, the quality of the processed surface can be significantly improved, meeting the increasing demand of modern manufacturing for high-precision and high-performance parts.