Papers by Author: Long Sheng Lu

Abstract: Ploughing technology has been applied in manufacturing micro grooves on the outer surface of copper tube. In order to study the formation of spiral grooves on the inner surface of tube, a FEM model operated on DEFORM is established. Two ploughing processes are simulated. At first, an initial groove is manufactured on the workpiece, and then a nearby groove, which will influence the initial groove's geometry, is manufactured with twelve feeds separately. The groove's geometries, including groove width, inclined angle and fin height, are detected. Geometry comparison between the two grooves show that different feed results in different groove shape. According to the geometry change tendency of grooves, the feed can be divided into three different intervals.

Abstract: 2D finite element model with the same material for backup to minimize the burr size was developed to investigate mechanism of burr formation and burr minimization. The flowstress of the workpiece and backup material are taken as a function of strain, strain-rate and temperature. Temperature-dependent material properties are also considered. The Cockroft-Latham damage criterion has been adopted to simulate ductile fracture. The crack initiation and propagation is simulated by deleting the mesh element. The result shows putting a backup material behind the edge of the workpiece is an effective way to minimize the burr size. The effects of cutting condition, temperature and different backup material properties on the burr formation and burr size can be investigated using the developed finite element model. This model could be useful in the search for optimal tool geometry and cutting condition for burr minimization and for the modeling of a burr formation mechanism.

Abstract: A passive microstructured mixer based on micro-ploughing technology with a multi-tooth tool is proposed. The mixer uses multiple three-dimensional nozzles to split one of the liquids into several micro-plumes. The fins on the surface of the nozzles induce a second liquid to generate turbulence around the local surface of the fins. The machining mechanism for fabricating 3D nozzles on a stainless steel sheet by micro-ploughing technology with a multi-tooth tool was studied. The machining process mainly involves four stages: tool-feeding, fin-forming, micro-hole-forming and tool-retracting. Simulation and flow visualization were used to evaluate its performance. The simulation results show the fin structure can induce local surface turbulence. The flow visualization indicates that when the flux is between 0.5ml/s and 3ml/s, the two liquids are fully mixed in 1second.