This study aims at the experimental investigation of the dynamic characterization of high-speed mechanism with great flexibility. We use the specific constraction mechanism TLJ as an example and focus our research on the influence of lumped mass and inertia moment. Using the auther’s KED analysis program KEDL, many important concepts have been put forward based on the results and some new conclusions have been drawn.

With increase of machine speed, the influence of elastic components on dynamic characterises has become a very challenging problem. In our paper, we use self-made fiber-optic sensor on-line to detect the elastic locus. The sensor has highly transmitting and collecting light properties so that steady elastic locus has high precision and distinguishabilty. A theoretical analysis has been conducted using our program KEDL. The conclusions reveal more information about the dynamic characteristics of high-speed mechanisms.

A three-dimensional (3D) numerical model is developed by using control volume method to analyze the effects of the electron beam scanning speed on the temperature distribution and fluid flow of the liquid phase in the electron beam melting® (EBM) of Ti-6Al-4V powder. The numerical calculations are performed by Fluent codes, in which thermal analyses with and without considering fluid flow in the molten pool are compared. A series of experiments are performed with an Electron Beam Melting® machine to verify the numerical accuracy. Compared to thermal analysis without considering convection in the molten pool, a closer numerical prediction of geometrical size of molten pool to the experimental data can be achieved by using thermal and fluid flow modeling. The difference between the melt pool geometry in the two models is due to the consideration of the effects of the outward flow in the fluid flow model caused by surface tension.

Laser transformation hardening (LTH) based on rapid heating and cooling cycles produce hard and wear-resistant layers of the metallic component. A high intensity moving laser beam heats up the thin layer of the external surface of the component without damaging the bulk of material. The metallurgical transformations taking place in the material during the thermo-kinetic cycles could effectively improve the mechanical properties of its surface. Nowadays, a high power direct diode laser (HPDDL) has been accepted by industry as a valuable tool to carry out this process. A three-dimensional (3-D) transient thermo-kinetic model has been developed to predict the temperature profile of the hardened layers of the material surface. The temperature-dependence of the thermal properties of the material is taken into account in the model. The laser beam is considered as a moving line heat source with a uniform distribution of laser power. The numerical solution is obtained by using a transient 3-D heat conduction equation with convection boundary conditions at the surfaces of the workpiece. A number of experiments have been carried out to harden components of AISI S7 tool steel by a continuous wave (CW) HPDDL at different power levels (1200 W – 2000 W ) and different scanning speeds (5 mm/s – 20 mm/s ). The main processing parameters such as laser power and scanning speed are optimized based on the numerical analysis of the heat conduction involved in this process. The numerical simulation results are compared with results produced experimentally by a HPDDL laser operating in CW, showing good agreement.