Papers by Keyword: Up Milling

Abstract: This paper deals with the up milling technology. It describes the coherencies of temperature and surface roughness achieved by this up milling process and explains the principle of up milling, briefly describes the heat generated too and shapes of chip. A main part of this paper is realization of the experiment, description of the experiment and evaluation of results shown as the resulting values of temperature and subsequent surface roughness and category of made chips. The milling is the most used technology in engineering and shape of chip is important for its transport and for economical aspect of this technology.

Abstract: The purpose of this research is to discuss the machining stability in of the up and down milling of three milling systems: 1) the feed-direction one-dimension, 2) the normal-to-feed-direction one-dimension and 3) the symmetric two-dimension milling systems. A simplified model with time-invariant parameters is adopted to simulate the milling process. In this model, the elementary cutting function, which represents the trajectory of cutting force for a certain local cutting edge, plays an important role in affecting machining stability of the different cutting configurations. This paper presents an in-depth discussion on the effects of cutting configurations and radial depth of cut on the elementary cutting function, and also on the stability lobes. It is found that the elementary cutting function of one-dimension milling system is a real number, as well as its positive and negative values will lead to totally different chatter features. Most technical literatures focus on the chatter features of positive elementary cutting function, while this research discuss that of both positive and negative ones. On the other hand, for the two-dimension milling system, its machining stability found to be dominated by the eigenvalues of the elementary cutting function matrix. The comparison of machining stability in up and down milling is then analyzed and three conclusions are drawn in this research. Firstly, the feed-direction one-dimension milling system has better machining stability in up milling. Secondly, the normal-to-feed-direction one-dimension milling system has better machining stability in down milling. Thirdly, up and down milling both show the same machining stability in the symmetric two-dimension milling system.

Abstract: In practical industrial processing, in order to make the tiny functional devices assembly accuracy as high as possible, which raises an very high requirement for surface quality of micro workpiece. Some of the important factors in controlling the surface quality with the level of the trajectories and forces of the blade across on the workpiece have a great relationship. This paper presents generalized mathematical models of the trochoid and forces combined with the helix cutter geometry used in the industry. And then from both of these aspects analytical laws in-depth of the trochoidal curves and micro-cutting forces variation. It will be of great reference value for the study of micro-milling mechanism.

Abstract: Significant research has been made regarding chatter stability of milling operations. This paper presents a 2 degree of freedom stability analysis model (2 DOF model) for interrupted cutting. The cutting process is divided into two parts namely “free vibration” and “forced vibration” considering the flexibility in x and y directions. Calculating the solutions of the two parts, a four-dimensional-single-variation discretization map is established and the eigenvalues of the Jacques Matrix are checked at the fixed point on the Floquet unit circle. The two Neimark-Sacker and flip bifurcations are evaluated. The research work shows that the up milling is more stable than the down milling under the same operating parameters. The comprison of the proposed 2 DOF model with Davies one degree of dimensional model (1 DOF Davieas model) has been made in the paper which shows that the area of stable region in the proposed model is greater than the stable region in the 1 DOF Davies model. In the last the results of the experiments support the proposed model has been verified by experimentation.