Study On Nc Milling Under Impulse Force Based On CNC System

In the metal cutting, milling is wildly used in the processing methods. Milling is in intermittent in the cutting process, which is affected by the external vibration and inherent vibration easily. The process of normal milling will be unstable because of stiffess of process. The machining accuracy and surface quality will be affected by the small displacement of tool and workpiece. This paper studies the mechanism of vibration cutting under the logic feed of workbench, which can strengthen the cutting process.In this paper, vibration milling of hardened 45 steel is studied. Machinability is poor when the hardness of this material exceeds HRC40, and this moment its characteristic is high hardness and intensity, prodigious brittleness, poor thermal conductivity prodigious cutting force, high cutting temperature, lower tool life, caused easily vibration so that the machining accuracy of workpiece is low and the surface quality is poor. By exerting certain regular and controlled vibration on relative cutting tool, cutting force and heat would be decreased and processing quality and efficiency would be improved. In this paper, the CNC machining methods of realizing the effect of pulse force is studied by the use of logic feed, which is engendered by using the CNC workbench. By programming instructions, that is to say, workpiece can realize the pulse of the force under vibration cutting mechanism according to required logic feed by the using the digital control system of numerical control processing equipment. The mathematical model of the milling established, and the differential equation is established and solved theoretically. the dynamic relationship between the tool and the workpiece is studied theoretically.the stiffness of the process system is measured. The law of stiffness and the affect of pocess is analysised .the relation of cutting perameter and logic feed and the speed of workbench with cutting force and surface roughness are studied. And the influence of vibration cutting frequency for cutting force and surface roughness are discussed in this paper. The dynamic displacement between tool and workpiece is analyzed though Matlab.Tests show that when the vibration frequency to meet the zero-vibration cutting conditions, cutting forces and cutting temperature significantly reduced, the surface roughness accuracy has improved significantly, hardened materials can be machined by the ordinary cutting tool.