薄壁件等离子弧熔覆快速成形的温度控制研究

Study on the Temperature Control Methods of the Thin-wall Parts Using Plasma Arc Deposition Based on Rapid Prototyping

介绍一种基于等离子弧熔覆的薄壁件快速成形工艺,通过数值模拟与实验相结合的方法研究不同的热输入与散热条件下,薄壁件成形中的温度分布规律及控制方法。研究结果表明:在成形中,当等离子弧功率不变时,薄壁件的温度会越来越高,导致因过度熔化而坍塌;随着层高的增加,逐步减小等离子弧功率,可以明显减少热输入,改善过度流淌等缺陷,但等离子弧功率过低时会导致无法将填充金属丝熔化而产生夹丝。提出一种减小等离子弧功率与跟随式直接水冷相结合的成形温度控制方式,有效控制了成形过程中薄壁件的整体温升,避免了薄壁件的坍塌、夹丝等缺陷,保证了成形质量。

A thin-wall parts rapid prototyping process based on plasma arc deposition was presented. Experimental and numerical simulation methods were used to investigate the temperature distribution and control method of thin-wall parts under different heat input and heat dissipation conditions. The results show that the temperature of the thin-wall part will be higher and higher while the power of the plasma arc is invariant during the building process, and it will result in excessive melt and collapse of thin-wall part. If decreasing the power of plasma arc gradually with the increase of the thin-wall part＇s height, the heat input will be reduced prominently, in the meantime, the excessive melt and collapse of the thin-wall part will be improved. But if the power of plasma arc is too low, the filler wire may be unable to be melted timely. A new temperature controlling mode by the combination of decreasing plasma arc power and follow-up water-cooled method was proposed. The whole temperature of the part can be availably controlled and the defects of the thin~ wall parts, such as excessive melt and collapse, can be effectively avoided.