| With the growing interest in energy efficient and environmentally friendly manufacturing,reducing energy consumption and improving energy efficiency have become one of the hot topics in the field of manufacturing research.More and more attention has been paid to green manufacturing engineering,especially after the proposition of Made in China 2025.Meanwhile,the huge energy consumption and low energy efficiency in the manufacturing process has been an urgent problem to be solved in the field of industry and energy efficiency researching.It is of vital importance to research on the energy efficiency of emerging manufacturing process,especially to carry out green evaluations on the new intelligent manufacturing method with high energy consumption and low energy efficiency features,which is formed by the laser metal direct deposition.In this thesis,through analyzing the energy flow of manufacturing process and the energy required to melt the deposition perform based on the energy used effectively in the deposition,the evaluation index of energy efficiency in laser direct deposition process has been established.And based on thermodynamics and the melting enthalpy required of the deposition volume,the energy efficiency model of laser direct deposition process under different process types including single-channel single-layer forming,single-channel multi-layer stacking,multi-channel single-layer lap and multi-channel multi-layer lap stacking have been established.Meanwhile,the method has been innovatively proposed by adding the WC powder during the experiment is aimed to change the grain size and show the deposition interface between layers obviously.A mathematical model of manufacturing energy efficiency correlated with the deposition process parameters only has been established after analyzing the results of experimental tests and measurements and making the regression identification on the key parameters in the manufacturing energy efficiency model such as the average temperature of the molten pool,the cross-sectional area of the sedimentary layer,the melting area of the substrate,the single-channel multi-layer energy coefficient and the multi-channel single-layer energy coefficient.The effect rules of technological parameters on process energy efficiency in the laser direct deposition process have been in-depth studied according to the mathematical model of the manufacturing energy efficiency.On the premise of ensuring the deposition manufacturing performance,a lower laser power,a larger powder delivery rate,a lower scanning speed and the lap rate of 0.5 should be selected to reduce the specific energy and improve the effective energy utilization.At the same time,the larger the deposition layers and the deposition streaks are,the more effective the energy utilization will become.A collaborative research approach between manufacturing energy efficiency and property in the laser metal direct deposition,which provides feasible basis for the synergy mechanism to explore manufacturing efficiency and property,has been proposed as a bridges including the range of common manufacturing parameter under the optimal manufacturing energy efficiency and property. |
