Research On The Chip Forces Modeling And FEM Simulation In Drilling Process

The chip shape is an important factor deciding the quality of drilling machining, in order to obtain good surface of hole machining, one of the keys is to choose the appropriate processing parameters to control chips shape. In this dissertation, the research object is the chips formation in drilling machining process, establishing mechanical model of drilling chip forces in the discharge process, and through the DEFORM finite element software and drilling process simulation conducted to analyze the factors in drilling process. Combined with the drilling experiments analyzed the chip shape’s influence on quality of hole processing. The main contents are as follows.(1) Mathematical model of chip forces during the drilling process. Mathematical model of cutting edge forcing on chip is based on the theory of oblique cutting. Combined with the reason of the drilling bit axial force established the mathematical model for the force spiral to chips. By using the computing methods of spiral curve, we can estimate the length of chips, combined with chips’ centrifugal force in rotational movement regarded as the positive pressure generating sliding frictional force, and established the mathematical model of hole wall’s friction on chips. Through the Matlab analyzed the influence of process parameters on chip forces.(2) Finite element simulative analysis in drilling process. We can establish finite element model of twist drill and three edges drill, use finite element software DEFORM respectively form two drill chips during the drilling simulation demonstration. Then, we need to comparatively analyze the drilling process of axial force, temperature distribution, the force of the workpiece and the simulation results of chips morphology, and coincide the prediction with drilling results by morphological simulation prediction of two drills’ chips process.(3) Analyzing the results of drilling experiment. Through the drilling 45# experiment, the surface roughness should be measured respectively under the processing condition of different cutting parameter and different blade number of drilling bit. Based on the multiple linear regression methods, the prediction model of surface roughness can be built, and then we can analyze the influence rule of different parameter on surface roughness. Using the dimensional visual image collector to shoot the chips produced inn the drilling experiment, we can analyze the cutting pattern’s influence on the surface roughness of hole processing.With the above methods, this dissertation completes the mechanics modeling of drilling processing chips and analyzed the main factors on the influence of the chip forces. The results of simulation predicted the drilling chip shapes really. Analyzed the drilling experimental results, the dissertation draws the conclusion that the chips pattern has influences on the surface roughness of hole processing, and it finds out the rule about how the main spindle speed, feed speed and the blade number of drilling bit influence the surface roughness of hole processing. The content of this research is mainly to reveal the essence of drilling process, improve the drill structure,and formulate the reasonable cutting technology. This has great importance in the aspects of enhancing surface quality of hole processing, reducing wear or breakage of the drill bit and improving the service life of drill bit.