Papers by Author: Ai Dong He

Abstract: Cryogenic MQL is a kind of green machining technology of the combination of cryogenic air and minimal quantity lubrication (MQL). The aim of this research is to determine if the cryogenic MQL technique in turning with Cutting tool with internal cooling structure gives some advantages in terms of tool life, surface roughness and cutting chip breaking. This paper reports the results obtained from turning tests, at one feed rates (0.12mm/r) and one depth of cut (0.4mm) and different cutting speeds (43m/min, 108m/min, 217m/min), and the results obtained show that using cryogenic MQL had some advantages in terms of tool wear, surface roughness and cutting chip breaking compared to using dry cutting and cryogenic air cutting. And the results obtained show that when cryogenic MQL and cryogenic air cutting were applied to high speed cutting, they had more advantages.

Abstract: Pre-stress Hard Cutting, known as a new machining technology, is the combination of hard cutting and pre-stress cutting. Some reports show pre-stress machining can improve residual stress state of machined surface and prolong fatigue life of mechanical part, such as drive shaft, bearing and engine vane etc. Based on the principle of this technology, this paper take aero-screw shaft machining as object, investigated the pre-stress loading method, experimental device and implementation process of pre-stress hard cutting. Experiment is carried out for aero-screw shaft with PCBN tool, cutting force, machined surface residual stress state and distribution are measured. The experimental results show that by using this method, residual compressive stress is got on machined surface and good surface finish is gained, hence it can control machined surface residual stress state actively and improve the fatigue life of aero-screw shaft..

Abstract: Machined residual stress is an important index in machining quality, and pre-stress cutting is a process which can increase the residual compressive stress on machined surfaces. This paper investigated the effect of machining parameters and pre-stress on residual stress of 40Cr steel by orthogonal experiment. The experiment results also showed that pre-stress could increase the residual compressive stress effectively, and it had obvious significance for residual stress than those significances of machining parameters; ap had more obvious affect on the residual stress than vc and f have, and residual compressive stress decreased with the increase of ap, vc and f. A prediction formula for residual stress of pre-stress hard turning was obtained from the experiment results and it was verified reliable by other experiment.

Abstract: This article proposes a method of three-dimensional modeling based on voxel code, which can build three-dimensional model by means of cubic voxels and Voxel code. Voxel code is the one that records the formation of physical location of the voxels piled up in turn order in the body. The different Three-dimensional shape can be constructed according to different codes. In order to reduce the storage overhead of the code, the linear octree coding and decoding are given in recording voxel code. Combined with VTK (Visualization Toolkit) programming, some voxel models have been visualization. The modeling idea and method proposed in this paper have a positive significance for the promotion of the research and development of related science fields and have their theoretical and practical value.