Papers by Author: Hui Ding

Abstract: In this paper, finite element thermal analysis and experimental study were performed to verify the design concept and thermal management of a smart cutting tool with internal cooling. The main idea is to build micro cooling channel within the tool and located close to the cutting tip, forming a closed-loop of the internal cooling circuitry. The cooling lubricant contamination will be avoided and the cutting temperature be reduced when cooling fluid flows through the closed channel. The cutting temperature at the tool tip can be estimated by measuring the cooling fluids temperature at the inlet and outlet of the cooling structure. Thermal modeling based on FEA-CFD is carried out by using ANSYS and FLUENT. The simulation results demonstrate that the innovative tooling design concept can effectively reduce tool temperature away from the extremely high temperature and sensing the cutting temperature at tool tip. Preliminary experiments have further proved the concept of the tool system.

Abstract: This paper presents the development and performance assessment of a novel 5-axis ultra-precision micro-milling machine (UltraMill) which enables ultra-precision micromachining of high precision 3D miniature components and micro features. An integrated design approach with motion accuracy, dynamic stiffness and thermal stability prioritized has been proposed and applied to analyze and optimize key machine components and their integration. Direct drives and aerostatic bearings with the squeeze oil-film damper are employed in the micro-milling machine throughout, which offers higher motion accuracy, improved dynamics and loading capacity. Micro-milling trials were performed on OFHC copper using tungsten carbide, CVD diamond and single crystal diamond micro tools. Both micro featured profiles and micro machined surfaces were measured to validate the proposed machine specifications and performance.

Abstract: In this paper, a 2-D vibrating platform is designed using dual flexure hinge structure and four significant structural parameters are optimized with the integrated model of Abaqus and Isight so as to improve the platform performance. The natural frequency is increased from 496.3 Hz to 2360 Hz after optimization while the distance of travel and the stress satisfy the constrains. The optimization results are confirmed with the test data. The optimized 2-D vibrating platform is applied into the micro milling and the machined surface quality is improved. Therefore, the optimized 2-D vibrating platform is a valid equipment to carry out 2-D vibration-assisted micro milling and study the cutting mechanism.

Abstract: Two dimensional vibration-assisted machining is applied into micro-milling to improve cutting accuracy and prolong tool life. In this paper, the tool tip path of two dimensional vibration-assisted micro-milling (2-D VAMM) with different vibrating parameters is simulated and analyzed. And the computation module of chip thickness in 2-D VAMM is proposed, based on which the chip thickness characteristics is investigated using two evaluating indicators: free time ratio (FTR) and amplitude ratio (AR). The effects of vibrating parameters on FTR and AR are studied with the help of Full Factorial Design and analysis of variance. It is found that FTR can be increased by increasing the ratio of amplitude in normal direction to the feed and the ratio of frequency in normal direction to spindle speed, while AR will be enlarged with increase of the ratio of amplitude in feed direction to the feed and the ratio of frequency in feed direction to spindle speed. The simulation studies are the foundation for calculating cutting force, tool wear and surface roughness in 2-D VAMM and can also guide the further experiment.