Methods for improving the surface quality of CNC turning precision turning
The improvement of the surface quality of CNC turning precision turning requires comprehensive measures from multiple aspects such as process parameter optimization, tool selection and maintenance, machine tool status adjustment, cutting fluid application and operation norms. The following are the specific methods:
First, optimization of process parameters
Cutting speed: Increasing the cutting speed helps reduce the formation of built-up edge and scale burrs, thereby improving surface quality. However, it should be noted that excessively high cutting speeds may lead to accelerated tool wear or overheating of the workpiece surface. Therefore, a reasonable selection should be made based on the material properties and tool performance.
Feed rate: Reducing the feed rate can lower the height of the residual area and improve the surface finish. However, a feed rate that is too small will reduce processing efficiency. Under the premise of ensuring surface quality, a larger feed rate should be selected as much as possible.
Cutting depth: During finish turning, the cutting depth should be relatively small to reduce cutting force and vibration and prevent damage to the workpiece surface.
Second, tool selection and maintenance
Tool material: Select the appropriate tool material based on the hardness, toughness and other characteristics of the processing material. For example, when processing hard materials, hard alloy or ceramic tools can be selected; When processing tough materials, high-speed steel cutting tools can be selected.
Tool geometric parameters: Reasonably select the main deflection Angle, secondary deflection Angle, tool tip arc radius and other geometric parameters of the tool to reduce cutting force and vibration and improve surface quality. For example, increasing the radius of the tool tip arc can disperse the cutting force and reduce the surface roughness.
Tool wear and replacement: Regularly inspect the wear of tools and replace severely worn ones in a timely manner. Blunt cutting tools can cause bright spots or scratches on the surface of the workpiece, seriously affecting the surface quality.
Third, adjustment of machine tools and fixtures
Machine tool rigidity: Ensure that the machine tool has sufficient rigidity to reduce vibration during the cutting process. The overall rigidity of the machine tool can be enhanced by adjusting the tightness of components such as the machine bed and guide rails.
Fixture stability: Select the appropriate fixture to ensure the stability and reliability of the workpiece during the processing. The clamping force of the fixture should be moderate to avoid deformation or loosening of the workpiece due to being too large or too small.
Spindle and guide rail accuracy: Regularly inspect and adjust the accuracy of the spindle and guide rail to ensure that the motion accuracy of the machine tool meets the requirements. The radial runout and axial movement of the spindle will directly affect the machining accuracy and surface quality of the workpiece.
Fourth, application of cutting fluid
Selection of cutting fluid: Choose the appropriate cutting fluid based on the processing material and cutting conditions. Cutting fluid should have excellent cooling, lubricating and cleaning properties to reduce cutting heat and friction and improve surface quality.
Cutting fluid supply method: A high-pressure and high-flow cutting fluid supply method is adopted to ensure that the cutting fluid can fully penetrate the cutting area, effectively cooling and lubricating the tool and workpiece.
Fifth, operation norms and skills
Clamping method: Minimize the number of clamping operations. Use one clamping to complete the processing of multiple surfaces to reduce the impact of clamping errors on surface quality.
Cutting sequence: Arrange the cutting sequence reasonably. Process the surfaces with higher precision requirements first, and then the surfaces with lower precision requirements. At the same time, pay attention to chip removal and cooling during the cutting process to avoid chips scratching the machined surface.
Operating skills: Operators should be proficient in the operation skills of CNC lathes, such as reasonably selecting cutting parameters, timely adjusting tool positions, and paying attention to observing abnormal situations during the cutting process, etc.
